I often do bait and switch on here and I should honour the title to some extent, so here it is. There’s much to admire about David Bowie and the world lost a genius a few years ago. I’ve blogged about him before and whereas I can’t be bothered to fish those bits out I do remember tracing his reference to superhumans in ‘Oh You Pretty Things’ back via Arthur C Clarke’s ‘Childhood’s End’ to Olaf Stapledon’s writing, particularly ‘Odd John’. But that isn’t what I’m thinking of right now. I’ll never forget the first time I heard ‘Space Oddity’. It was an oddity to hear that accent on the radio. I don’t know why exactly, because there were lots of southern English rock stars at the time, but somehow it seemed really, I don’t know, ground breaking. Of course he was groundbreaking in other ways. My ex is a big Bowie fan, and has found him a gateway into sci-fi, a genre she previously despised, but as I said to her, and for some reason I think this applies to him in particular, you can’t take things too far from his lyrics without ruining them. For instance, in the album ‘Ziggy Stardust’ and his Mott The Hoople single ‘All The Young Dudes’, we seem to be expected to believe that there will be a mains supply for electric guitars, organs and amplifiers during the apocalypse. In fact, maybe there will be and that’s a mark of his visionary nature, but it bothers me. They should’ve been acoustic.
What I have in mind today though is ‘Life On Mars’. This has now famously been used as the basis for the excellent time travel police procedural series, which to me felt like Sam Tyler travelling back to a time when things were “normal”. Unsettlingly, that series itself is now almost twenty years old and the same gap separates us from Windows 3.1 as Sam Tyler from Gene Hunt. Well, sort of – no spoilers! My take on the track itself, though, is that it’s about someone despairing of how life is here on Earth and hoping there’s life on Mars instead because at least then there’d be something better out there. I’ve said before that my greatest fear is that there is no life elsewhere in the Universe, mysterious encounters in Sussex chalkpits notwithstanding. This is also why I’m so peed off with the scarcity of phosphorus. Anyway, this is in fact a major reason why I’m so focussed on the possibility of alien life. I may have just written a nine thousand word long rambling blog post about silicon-based life, but the subtext is the same as Bowie’s song’s. As Monty Python put it, “pray to God there’s intelligent life somewhere up in space, ‘cos there’s bugger all down here on Earth”. I don’t entirely agree with that by the way. I think many of us choose not to think complexly, which is one reason we’re in this mess.
Okay, have I done enough of that now? Enough relatable stuff? Seriously though, I’ll try not to go off on one.
Because as you must know by now, it really looks like there might at some point have been life on Mars, according to recent discoveries there. I have to admit that at this point in the proceedings I have little idea what they’ve found, but I seem to remember it’s an iron compound which is found as a product of terrestrial life, possibly a sulphur one, which needs to have quite a lot of energy input to form but is then stable and has no known non-biochemical routes to its formation, that is, including the biochemical route involving the evolution of a technological species which can do sums like many of us, which I’m sure nobody sensible is suggesting. This is the latest stage in a long history of claims about Martians, and at some point it was considered so certain that there was intelligent life there that a competition for ways to communicate with aliens specifically excluded Mars because it was thought too easy. There have been claims of canals, lichens, and later on a scaled-down set of claims regarding something like bacteria. In particular there was the Labeled Release (American spelling) Experiment on the Viking lander which appeared to show positive results, i.e. the results which NASA had pre-decided would be best explained by life, but the problem was that the other two experiments were negative. It’s frustrated me until recently that they did this but right now it seems more like the way the scientific method works: come up with an idea, test it and then do everything you can possibly think of to prove a positive result wrong. On the other hand, looking at it non-scientifically at the time, it felt like they were in denial about the existence of life, possibly because it’s an audacious and potentially career-ending claim if it ends up being refuted, but also because it’s such an Earth-shattering claim. But this puzzles me a bit because in fact for a long time, since at least 1877 up until 1965, it was basically considered a dead cert that there was life there, and often also on Venus at the same time, and it didn’t seem to make much difference to the human race that we thought it was out there. Maybe this is to do with most people not being very focussed on space, but at least in the ’50s and ’60s this was definitely not so and in fact this was probably one source of inspiration for Bowie’s track. Getting back to Viking, it’s now thought that the results of the experiment were caused by perchlorate in the soil, a bleach-like substance which it’s also been claimed originated from the sterilisation process in the reaction chamber before the lander left Earth, although I think it’s now established that perchlorate is high in Martian soil. In fact I seem to remember (look at me failing to check my sources – sorry) that it makes Andy Weir’s ‘The Martian’ unfeasible, though maybe ingenuity would’ve got him out of his predicament some other way. Weir has since said that Watney could’ve washed it thoroughly first, so maybe, although wouldn’t he then have ended up with most of his water full of bleach? Maybe not. I’m not a chemist. There’s also been a view that the dendritic appearance of some terrain close to the poles is due to the action of microbes, something I went into in depth when I put the Martian calendar for 214 TE (telescopic era) together if anyone remembers that – it involved me throwing an inkjet printer into the larder with considerable force at one point.
What’s happened is that the Perseverence Rover in Jezero Crater has found what they call “leopard spots” on rock samples. Organic carbon-containing mudstones have been found to contain nodules and reaction fronts rich in ferrous iron phosphate and sulphide minerals. Vivianite is one possible candidate, which probably coincidentally is found in bivalve shells, and another is greigite, which is a ferrimagnetic mineral regarded as a biosignature, in other words a sign of life. Other processes which could have produced these minerals involve heating which doesn’t seem to have happened to the rocks in question as they would show other signs, for instance in their crystal structure. It seems that redox reactions have occurred there, that is, reactions involving the transfer of electrons between substances, one example of which is burning and another internal respiration. These rocks are around three thousand million years old, and at that time the same chemical reactions were occurring on Earth, mediated by microorganisms. So there are these two neighbouring planets on both of which chemical reactions usually associated with life are taking place. On Earth, it’s known that this is due to life, but what about Mars? The paper in question has eliminated other possibilities as likely explanations. Further investigation by NASA is of course not likely to occur due to funding cuts, but China might end up doing a sample return mission, that is, bringing samples back to Earth, in the next decade.
For me there are a couple of takeaways from this. One is that space exploration moves agonisingly slowly. This is probably an artifact of being born in the 1960s CE., but I was under the impression that there would be a human mission to the Red Planet from 1979 to 1981. This then got repeatedly postponed. The other is that science tends to do the same thing, although it’s also punctuated by revolutionary bursts of activity, according to the philosopher Thomas Kuhn anyway. It’s very cautious and tries hard to be boring. We seem to be edging very gradually into a position of accepting that there has been life elsewhere in the Universe, and that it was also found elsewhere in this solar system in a similar condition to its state on Earth at the time. Whether it exists on Mars now is another question, although of course “life finds a way”. Whereas that’s a bit of pop-culture tat, there is an element of truth in it and to be fair it’s quite a good line. You only have to look at a seedling growing between two paving stones to see that, but living on a practically airless, arid rock bathed in ultraviolet and dropping daily below the temperature of Antarctica is a considerably taller order than that. Maybe.
There are several possible worlds in this solar system other than Earth which may be hospitable to life as we know it. These include Venus, Mars, Ceres, Ganymede, Callisto, Europa, possibly Jupiter, Enceladus, Titan and maybe even Triton, Pluto and Charon. Several of these are quite a bit friendlier to it than Mars, although the question of it arising in those places in the first place also arises. Maybe it didn’t arise on those worlds though, and simply seeded them having arisen in space. If that’s so, maybe it’s the cloud that formed this solar system which gave rise to life, which then arrived on various planets, moons, asteroids, comets, wherever, and either died or, metaphorically, took root there. If that’s so, with reference to the previous post on here, it would probably show up as having the same chirality of molecules as we, i.e. left-handed proteins and right-handed carbs. It’s been suggested that life here must have pre-dated the Earth for two reasons: it seemed to arrive almost before it was possible for it to form, and looking at mutation rates in DNA takes it back to a point before the formation of this planet. To clarify, there’s a set mutation rate in DNA and RNA which enables scientists to date roughly when diverse organisms had a common ancestor, and incidentally this is usually before the first definite members of two groups turn up separately as fossils, which could mean a couple of things. The complexity of many genomes has increased over time as well, and this too can be measured from the genes which organisms still share. If you extrapolate these rates back to the point where the minimum information for an organism to function is present in the genome, you get a period of about nine or ten thousand million years ago, or roughly twice the age of the Earth. This isn’t generally regarded as solid evidence though. What it does suggest, interestingly, is that not only does life here descend from organisms present in the solar nebula, but actually it’s from a source which existed before this solar system had even begun to form.
I’m not going to base anything firmly on that possibility, but others have been suggested, one of which is that life arrived here from Mars aeons ago, which is supported by the likelihood that Mars was probably actually friendlier to life back then than Earth was. These redox reactions may be from the exact same taxon of organisms on both planets. And this is where it gets difficult.
David Bowie asked “is there life on Mars?”, but was this the right question? Many people have said that if life can be found there, or in or on any other world in this solar system, it guarantees that there’s life elsewhere in the Universe. Well, it really, really does not. Suppose we do find incontrovertible evidence that there is, just now, life on Mars, and also on several other worlds in this solar system, and moreover that it’s remarkably similar in some ways to life on Earth, for instance possibly sharing some genes with us, and has the same chiralities in proteins and carbs as us. That means that all of that life has a common ancestor. That common ancestor might have arisen in this solar system, or at least locally before this solar system formed. In terms of chirality, maybe there’s something about the processes of the Universe which lead right- and left-handed molecules of the respective types to form and persist while their mirror images don’t, or maybe there’s something about mirror life which means it won’t function, in which case all life of the kind we know in the Universe would have those chiralities for some very fundamental reason, but we’re still drawing conclusions from a very small sample. Maybe there’s either just something about this solar system which makes it more likely that life would emerge here, such as the relative abundance of phosphorus, or maybe it just did emerge here against all odds because we live in a very large Universe, many of whose planets are covered in a reddish-brown tarry goo instead of life.
For all we know, planets and moons here could be rich in life forms, and that would be a cheering thought, but that doesn’t of itself guarantee that the rest of the Cosmos is not utterly barren. For all we know, there could be endless lifeless worlds filling the Universe, which nothing whatsoever wrong with them but simply because the chances of it arising are vanishingly small. I’m sometimes haunted by the thought of some very, very Earth-like planet orbiting, I dunno, Delta Pavonis or whatever, with a perfectly comfortable surface temperature, oceans, continents, rain, thunderstorms, rainbows, mud, puddles children would love to splash in, sunsets over idyllic beaches lovers could walk along, or other phenomena alien beings could appreciate in their own way if they existed, but which will never, ever even see a single bacterium before their stars overheat and destroy them. Trillions of them, all without life. And this solar system being full of life would be of no significance, no consequence to that situation, because life just arose this one time. And this is why I say that if it could be proven that life existed nowhere in the Universe, I would stop worshipping God. It’s like a deal-breaker in a relationship for me. I would be terminally angry with such a Creator for sustaining in existence such a vast and uninhabited Cosmos. It would be really bad.
This, then, is why I say David Bowie is asking the wrong question. It’s the right one if understood in terms broader than just Mars, that is, if Mars is just a stand-in for another planet or other location where life could persist. Mars is just our next door neighbour, and we already know our bushes might end up growing over the fence or our aphids might end up infesting next door’s roses. Big deal. The Universe is so big that the size of this solar system is nothing to it.
My eyesight is terrible. When I go to the opticians for a new prescription as opposed to handing over the new one, they use a special chart with a single letter filling all of it and ask me if I can see it at all, and the answer is always no. Because of this, as a child I expected to go blind and trained myself to find my way around without looking, which annoys Sarada as it seems to mean I notice details more than I do large objects, although that’s probably partly an aspect of my neurodivergence.
Therefore, in general when I look up at the night sky without binoculars or a telescope, I see very little because the starlight is too blurry if I don’t wear glasses and if I do the lenses cut out most of the light. Most of the time, it’s hardly mattered because, for example, in Loughborough the sky was overcast at night or ruined by street lamps. However, here in southwest Scotland, the situation is different, rather like that in and around Herstmonceux, where I trained as a herbalist and where the Greenwich Observatory was moved when the skies got too bright. This region is one of the dark sky sanctuaries, although apparently it gets darker even than this a little to the west:
Compare this to South to Mid-Wales, the South of England and the English Midlands:
Much of Devon and mid-Wales are fine there, but I’ve never lived anywhere near them, and the area around Herstmonceux is now pretty much the same as the rest of the South nowadays.
Surprisingly, on looking at the sky here, as I did the night before last, through binoculars and with my eyes plus spectacles, I was able to perceive another, well, spectacle in the form of a clear sky and a vista out into the local arm of the Galaxy, as well as of our closer neighbours Mars and Jupiter. The lunar absence helped but the magnification of the binoculars decidedly didn’t, as it was impossible for me to hold them steadily enough to see either planet clearly. For some reason the binoculars I use are 16 x, which I understand are usually mounted on a tripod for this reason but they don’t have anywhere to screw them in. I’m guessing you can get a frame of some kind to address this issue but I don’t think I have one. Frustratingly, I finally found the telescope yesterday, too late to aim it at the sky on that particular occasion but tomorrow is another night.
It was helpful that Mars was so clearly visible. I understand it’s currently near opposition, i.e. about as near as it gets, because it’s quite distinctive and enabled me to find Castor and Pollux, as it’s currently in Gemini, which in turn helped me find something I’ve never managed to see before: Praesepe, also known as the Beehive Cluster. Before I dilate on this, I want to point out that turning one’s attention to the stars is a fantastic escape from the troubles of this microscopic blue dot, and perhaps also a unifying factor, but there is unfortunately nowadays a fly in the ointment because of Elon Musk’s satellites interfering with a clear view of everything. However, I don’t want to dwell on that.
I’m sure you’re familiar with the bundle of eggs a spider lays – a ball made up of the mother’s embryonic young yet to hatch. When they do emerge, they scatter themselves having eaten the mother’s body, at least according to ‘Blade Runner’ if that’s not a false memory. This brings to mind how stars form in globular clusters like this:
Sid Leach/Adam Block/Mount Lemmon SkyCenter
After a while, they fly apart and the result is an open cluster like the aforementioned Beehive. Other nearby examples are the Pleiades and Hyades, quite nearby in our sky. Cancer, the constellation where the Beehive is, is generally quite dim and I had the impression that the cluster was too but apparently its total brightness is something like 3.7. I should explain what this means. The faintest stars visible to the naked eye of someone with good eyesight are of magnitude six, and the brightest, one hundred times brighter, are around magnitude zero, an example being Vega. This makes it a logarithmic scale with each step around two and a half times that of the one above. It also illustrates that we perceive things such as brightness on a logarithmic rather than linear scale, and a similar scale for sound volume, decibels (which are not actually a unit of loudness but it’s too involved to explain here), doubles every three, so 86 decibels is twice as loud as 83. I’m just going to say one more thing about decibels which indicates their oddness: how far from the sound source are you when you judge it? A seventy decibel sound ten metres away becomes a seventy-six decibel sound five metres away because it’s four times as loud. But does it?
Praesepe, the Beehive, is a fuzzy patch in Cancer around six hundred light years away larger than the Sun looks in our sky, with a magnitude of 3.7. That means that all the stars together are that bright, and it’s the area which is that bright rather than the mean magnitude of all the stars in the cluster. There are supposed to be about two hundred stars in it altogether, although being an open cluster its edges are vague, although it’s about twenty light years in diameter. “Praesepe” means “manger” or “crib” (I’m from Kent so I say “manger” for both, which I suspect is dialect and I’ve never used it outside Kent, but I don’t honestly know), and it is in fact a nursery for stars, so it’s peculiarly appropriate. You only get one chance to use that though, so although the other open clusters are also nurseries they can’t be called that too. The Pleiades or Seven Sisters, probably the best known open cluster, consists of stars which are mainly roughly the same size and temperature as each other, being blue giants, but the Beehive is not like that. The Seven Sisters are actually younger than the extinction of the non-avian dinosaurs, but the Beehive is about six hundred million years old, so it’s considerably older than the first trilobites. It varies a lot more, containing white dwarfs, red giants and also yellow dwarfs, which are Sun-like stars. Moreover, several of these stars are known to have planets and one of them has at least two if I remember correctly (I always write this stuff off the cuff). However, as is very common, they’re all “hot Jupiters”, that is, they are red hot, partly vapourised planets which would’ve been rocky at a greater distance. Using the current popular method, hot Jupiters are easier to detect than other exoplanets because they’re large and closer to their suns, as it involves measuring fluctuations in brightness, which is likelier to be detected if the planet is relatively large compared to its primary and orbits it quickly. The planet also needs to be orbiting edge-on to our view. There are other ways of detecting planets but they haven’t been used for decades, and when they were it turned out they produced spurious results, such as simply recording when the lenses in telescopes were cleaned and put back at a different angle! Nowadays, it seems feasible that they would work, so I don’t know why they’re not using them.
There are roughly a thousand stars in an approximate sphere with a radius of ten light years, and those are just the ones detected from Earth. There are probably more because many of the known closest stars to our solar system are red dwarfs, the lightest and smallest stars, and the smaller a star type is, the more common it tends to be. A sphere with a radius of ten light years has a volume of around 4200 cubic light years, and with two hundred stars in the cluster that means a cube with a volume of 4.2 cubic light years on a side would contain on average one star and the mean distance between stars in the cluster would be only 1.6 light years. However, if they’re anywhere near randomly distributed, that distance is likely to vary quite a lot although the centre of the cluster might be denser, as can be seen from the photograph if those alignments are not optical illusions. There are many optical double stars in general which just happen to be along the same line of sight. This means that even given the known stars, which include red giants, the sky of a planet in the cluster would be a lot fuller and brighter than Earth’s, always assuming its atmosphere isn’t too dense or cloudy to see through and that it isn’t very close to its own sun. If we were that distance from α Centauri, it would be about as bright as Venus and capable of casting shadows, and if a red giant the size of Arcturus were involved it would be getting on for lunar level brightness and light up the whole sky.
Back in the 1960s or possibly the ’70s, a nuclear-powered starship called Daedalus was designed which couldn’t be built because it would violate treaties on nuclear weapons. However, if it had been, it could’ve reached the nearest star within fifty years. In a cluster such as this, it might take only twenty years to get there, which is a much more manageable interval. There are Sun-like stars in the Beehive and there’s no reason to suppose they don’t have Earth-like planets circling them, perhaps many such planets throughout the cluster. And there’s more.
One thing which really stimulates evolution here on Earth is frequent mass extinctions. For instance, something massive hit this planet sixty-six million years ago which led to the ascendance of the mammals. Various other causes led to other mass extinctions, some possibly due to other impacts. Had none of that happened, evolution might not have led to us appearing because life would’ve been too easy on this planet. Hardship and adverse circumstances lead to creativity here too. Furthermore, Earth is unusual in having a large moon, due again to a major impact, this time from an object the size of Mars, which led to the development of a strong magnetic field protecting us from ionising radiation. All of those events are more likely in the cluster due to its crowded nature, with stars interfering with each others’ comets and asteroids, but as said before, it’s only six hundred million years old and it seems unlikely that there could’ve been enough stimuli for even the simplest multicellular life forms to have evolved in that time. However, if that did happen in such a cluster, interstellar travel would be far easier to achieve than we find it, as would observation of other star systems. For instance, planets orbiting a Sun-like star would be on average sixteen times brighter when observed from adjacent star systems than they would be from α Centauri.
As I’ve said before, I try not to focus too much on life, intelligent life, life as we know it or humanoid life on this blog because that’s a bias which I think makes the Universe less interesting, and the emphasis on life is a bit anthropocentric and perhaps also rather science fictional.
Half the mass of the cluster is contained within 12.7 light years of the centre and its gravity is capable of pulling stars towards it from thirty-nine light years away. There are also stars moving through it which have no real association with it. It shares motion with the Hyades, the closest star cluster of any kind to us, and its composition is similar, so they were probably once part of the same structure. They are only 150 light years away from us.
It’s a trite cliché that artists have to draw what they see, and with twentieth and twenty-first century art it seems to be false. Perhaps with Fauvism an artist might attempt to concentrate on how she might see a particular shade or hue and paint it as that colour throughout, or at least that’s the impression (!) I got. In fact it seems to be nothing like that, but it does force the viewer to see the geometrical components of a scene while retaining one’s emotional relationship therewith, or maybe the artist’s feelings. Cubism, a couple of years later, concentrates on geometry while removing emotion.
Right now I feel that my tour of the Solar System has to some extent placed me in the second category, but only somewhat. I expect, if someone had genuinely visited other worlds, if their experience of Earth on their return would be more emotionally charged. I’m sure they’d never be the same again.
There will be something like poetry. Where it starts is another matter.
In the park near us, there’s a small fountain in a pond. Its drops describe a series of parabolas. These parabolæ radiate from the central showerhed and rise maybe fifty centimetres from the water surface. They remind me, right now, of nothing so much as a volcanic eruption on Io. With its exceedingly tenuous atmosphere and gravity less than a fifth of Earth’s, the fountain of ejecta from Io’s volcanoes resembles the fountain in the park but is cyclopean in extent, being over 150 kilometres high. However, the same laws of physics govern the movement and form of the drops. This was the first alteration in perception I became aware of.
Swerving into herbalism territory, like most Western herbalists my stock-in-trade substantially comprises a series of bottles containing what probably look like thick brown liquids to most people. These are usually ethanol and water solutions containing dissolved active ingredients of the plants in question. I could go into more depth about the more subtle distinctions herbalists perceive in the appearance of these tinctures, but for quite a number of them the residue remaining if some is spilt and the solvents evaporate becomes a tarry, often reddish-brown substance which is often a mixture of tannins and other compounds. Tannins are generally linked rings of organic molecules with hydroxyl and oxygen groups. Bakelite is another example of a substance made of these phenolic rings, and the brown or black appearance of a caster, mains plug or saucepan handle is often due to this. And out there in the depths, or maybe heights, of the outer Solar System are countless worlds covered in tholins, which are in some ways similar to this residue, though not necessarily phenolic. The sticky, reddish-black tincture residue is substantially similar to the same stuff coating the surface of many TNOs.
Another parallel with herbalism occurs when certain worlds are cold enough to have frozen nitrogen on their surfaces, such as Pluto and Triton. This brings tholins into contact with the element, leading to the formation of organic compounds containing nitrogen. These are quite similar to alkaloids. Alkaloids are a group of compounds which each have some of the following characteristics: they all contain nitrogen and have a markèd physiological action, tend to have rings including a nitrogen atom, and originate from plants. There are exceptions to the last two and the function of the alkaloid for the plant in question isn’t clear – they may act as reserves of fixed nitrogen. Alkaloids include caffeine, nicotine, atropine and cocaine. There are research programs to find novel alkaloids in rainforest plants for medical use, a race against time thanks to deforestation. Well, heinous as that may be, it so happens that many outer system worlds are coated in nitrogenous organic compounds, and this is just me but I do wonder if there are many such compounds out there. Maybe there could be heroin mines on Charon. The Universe doesn’t care about that.
The way tholins spread across the surfaces of the likes of moons and asteroids is reminiscent of how mould, lichen or plants colonise a new habitat. They are, as I’ve said before, a fork organic chemistry can take when free from technological influence instead of coming alive. It’s literally true to say that there’s an organic quality to tholins. Alternatively, maybe the way tholins went on Earth involved a freak accident with them coming to life. Consequently, when I look at a road surface, wall, pavement or other stone-like artifact, I see a parallel to the surface of a distant planet, where reddish-brown tar is gradually being deposited, just as moss and lichen gradually creep across these fresh plains. The difference is that in spite of the amazingly gradual encroachment of lichen at about a millimetre a decade, it’s still thousands of times faster than the rate of tholin deposition.
I don’t know if you’ve ever been to Dungeness. This area of Kent, held constantly in place by shingle lorries shuttling to and fro 24/7, is an example of a rare type of habitat known as a shingle bank whose largest examples on Earth are it and Cape Canaveral. The delicacy of this landscape is such that walking across it will leave footprints visible decades later due to the slow-growing foliose lichen living there. It has to be said that putting one of NASA’s main launchpads there is rather questionable, and much of what I’ve been able to write about in this series is contingent on environmentally questionable launches from that location. Dungeness at least has a lot in common with the lunar surface in that the footprints and human influence there, and doubtless in Cape Canaveral too, are extremely durable. Dungeness has been compared to “the surface of the Moon”, and this could equally well be inverted to comparing the surface of a distant planet to Dungeness. Titan in particular springs to mind.
On the whole, the view from moons, planets and asteroids on the Universe is either obscured or clear. There is a strong tendency for conditions to be close to extreme here. Either the sky is completely clear or completely cloudy. This is not universally so. For instance, on Mars clouds do occur but on the whole the sky is empty of them. Earth is cloudier than Mars but not as cloudy as Venus. This is one situation where I may not be aware of conditions outside the British Isles and over much of the planet the sky is either usually clear or mainly cloudy, but there are even so areas where there are, for example, little fluffy clouds in a blue daytime sky. The clouds on this planet are usually mainly water ice or water vapour, but the volcanoes are usually silicate rocks.
It needn’t be this way. Martian clouds are generally either water ice or dry ice, i.e. carbon dioxide. On the outer planets they’re various, sometimes evil-smelling, substances like ammonium hydrosulphide or hydrogen sulphide. On Titan they’re methane, and form a largely uninterrupted deck of obscurity. One notable thing about all these clouds is that none of them actually constitute a substantial part of the world in question’s atmosphere. Our own atmosphere, for example, is not mainly water vapour, and if it was this planet would be very like Venus and completely uninhabitable with no rivers, lakes, seas or oceans, because steam is a much stronger greenhouse gas than carbon dioxide. Likewise with the prominent clouds elsewhere in the Universe. Even so, there are circular storms, thunderstorms and plenty of cloud types approximating our own, as well as the same formations. On Mars, Earth and perhaps elsewhere, a peak can push a body of air up past the point where it starts to form clouds, and on its leeward side chains of clouds can develop in similar manners. This is of course not always so. Rain clouds of any kind whose drops actually reach the ground are only found on Titan and Earth in this star system. Something like snow is more common, but is sometimes the atmosphere itself freezing. Hence when you look at the sky, you’re seeing clouds like those on countless billions (long scale) of worlds throughout the cosmos.
These processes and structures can be composed of less expected materials in other star systems. A particularly easy kind of planet to detect by the method of looking for light being dimmed by a large body passing frequently between us and the star is the “Hot Jupiter”. These are, as the name suggests, somewhat Jupiter-like planets, but differ from our own largest planet in that they orbit their primaries in a couple of days and are far hotter at their cloudtops than any planet’s surface in our own system. Consequently, although they too have clouds “like” ours, they’re actually made of substances like droplets of molten titanium or quartz, or perhaps crystals of the same. Meanwhile, circling the Sun and doubtless innumerable other stars further out than Earth, the converse situation exists, with volcanoes made substantially of water ice and erupting water instead of silicate, while the clouds are made of ice or water vapour instead. This is as extreme compared to a world like Enceladus, Titan or Pluto as the silicate clouds are to us.
Taking the comparison a bit more deeply, the water that erupts out of volcanoes in the outer system emerges from a mantle of flowing slush analogous in the same way to our own rocky mantle, which does flow but is not really fluid as we understand the term as it’s extremely viscuous, but just as far out moons hide internal water oceans beneath a superficial veneer of ice, though sometimes a very thick crust thereof, so does our home world secrete a deep ocean of rock. It’s easy for us to imagine that somewhere like Europa or Enceladus could be concealing a vast reservoir of sea water replete with its own version of fish because we are ourselves familiar with that from our own seas. Extending that to our own mantle, who are we to say that there are no “fish”, perhaps silicon-based, hundreds of kilometres beneath our feet? After all, the ocean of rock is hundreds of times larger than the ocean of water on our home world. This can only be speculation, at least right now, and it’s hard to imagine how it could become anything else. Maybe there is an extremely hot Earth-sized planet whose lava oceans do contain life forms, or maybe not, but we’re looking for “life as we know it” when the one thing we really do know about life elsewhere is that we know nothing of it, or even of its existence.
And perhaps we will never know. Clearly nothing we’re aware of now could rule out the presence of other life off Earth, because we have an example of life here, but although there are numerous reasons we could project onto the sky that might make it implausible, it’s entirely possible that we’ll simply never know if we’re alone in the Universe, and that might apply even if we embarked on an exploration of it. Even if our entire Galaxy proved to be lifeless apart from us, there might be no particular reason for it other than luck, and another galaxy, such as Andromeda, could have life, and if not that a different galaxy so many gigaparsecs from us that we’ll never know it exists. Right now there doesn’t seem to be any kind of mathematical or scientific argument which would be able to give us an answer to this question. It’s rather like the existence of God. You can be “theist”, believing that there is life elsewhere. You can be “atheist”, observing the Universe and the physical laws which decide what can be in it and deciding that life is just a fantastically improbable freak accident, thus committing yourself to the probability that terrestrial life is all there is. Or, you can be agnostic, and simply withhold an opinion on the matter, while holding out for the possibility that there is or is not on a kind of faith-like basis. It’s even possible that we will never know if there’s life within our own planet.
Getting back to precipitation, there is a line from the TV series ‘Wonder Woman’ which seemed highly dubious when I first heard it. A man from the future visits the late 1970s and remarks to her that there are planets made of diamond where a stick of wood would be a previous commodity. At the time I suppose I assumed that other planets were more like our own than they in fact are, because remarkably for such a soft and unscientific franchise as ‘Wonder Woman’, with the likes of disappearing handbags and invisible aircraft, this is in fact so, and you don’t even need to look outside our own star system to find such planets. Both our ice giants are probably so rich in diamonds that they’re as common as icebergs in the Arctic or hailstones on a spring day, and wood would naturally be unheard of. Wood is also associated with life of course, and we have no idea how specific it is to Earth. If it is, it’s like blue john, which only occurs in one place in our Solar System and probably for many light years further than that, in the Derbyshire Peak District.
Water has influenced the appearance of the Peak District in a couple of significant ways which give the area its distinctive character. One is through the erosion of potholes and other caverns and another is the various effects of glaciers, such as causing lakes to form by blocking rivers and the presence of isolated boulders a long way from their original locations. It isn’t clear what actually happened there in that respect during recent ice ages, but it seems that ice-related erosion and weathering relatively close to melting point where ice expands as its temperature falls is likely to be characteristic of Earth as an ongoing process rather than anywhere else in the system, although during certain relatively short-lived catastrophes this does seem to become significant. The difference here is that in many places the temperature has fluctuated around the range where this takes place, making it a dynamic and repetitive process.
Looking up, we may see Cynthia. I’ve been rather startled to find recently that for some reason flat Earthers perceive her as luminous! She looks like nothing so much as a ball of grey rock to me. A varied and beautiful one to be sure, but not luminous. This impression, though, is not confined to our satellite. The other planets in the system do in fact look like bright stars to the naked eye. Even so, there are noctilucent clouds, which are so high in our atmosphere that they reflect sunlight considerably later or earlier than sunset or sunrise. It’s simply that unexpectedly daylit items in the night look so bright by contrast that they’re practically luminous, but not literally so. It illustrates how much the human eye can adjust to light and darkness that Cynthia can appear to shine. Yes, there is moonlight. Also, the light from the white door in our bedroom reflects onto the blue-painted wall, almost bringing us back to Fauvism.
When Sarada became aware that I tended to get bogged down in details, she recommended a book to me which I very much enjoyed: ‘The Mezzanine’, by Nicholson Baker. Baker’s book, which can hardly be described as a novel, focusses on the minutiæ of the quotidian in a manner possibly reminiscent of «A la recherche du temps perdu». Whereas I find the latter unhealthily self-absorbed (though I haven’t read it), the former caught my attention and was easy to relate to. It has no real plot and has been described as having a “fierce attention to detail”. As a young adult, I used to write long descriptions which I couldn’t turn into stories. Fortunately, Baker has succeeded in getting a work using a similar approach published. Most of our experience, mine at least, consists of such thoughts and unfinished mental doodles. One difference is that ‘Mezzanine’ finishes these. The approach taken is somewhat reminiscent of a minor poetic movement of the late twentieth century called “Martian Poetry”.
Martian Poetry is a small and fairly transient subgenre of poetry whose most famous piece is Craig Raine’s ‘A Martian Sends A Postcard Home’. This can be found here. It can take a while to puzzle out, but refers to such things as books, telephones and sleeping together. It’s a series of riddles, but more than that. Published in 1979, it uses unusual metaphors to make everyday objects and experiences fresh and unusual. It’s a little like the real-life ‘Man Who Mistook His Wife For A Hat’ and it raises the question in my mind of who the narrator is. When I wrote the previous post, I realised I’d created a problem. I had no idea who the aliens describing Earth were and I had to come up with a semi-feasible model of their own world, anatomy and physiology before I could begin to portray our home planet. In particular, I had the alternatives of making their comfort temperature hotter or colder than ours, and chose colder because more of our own star system, and in fact the whole Universe, is colder than Earth’s surface rather than hotter. Once I’d done that, I had something I could relate to and a perspective from which to conceive of Earth as others see it. Craig Raine, unsurprisingly, doesn’t do that. We can, however, glean something about the narrator because of the metaphors used, which can be contradictory. For instance, he uses the word “caxtons” to describe books, which he sees as avian, multiwinged creatures. This is a spiky-sounding word with its C and X, and calls to mind a rustly, fluttering thing which one might imagine capable of flight, and certainly it confers that capacity to its reader’s mind, but calling it after the fifteenth century printer anchors it in human life, and even in England. Nor does Craine play fair with the reader when he later describes mist as making the world “bookish”. The problem Craine sets himself is that of not being able to make the narrator Martian enough, because that would seem to make the poem less comprehensible.
I tried fairly hard to find another example of a Martian poet, but all I could uncover was Christopher Reid’s ‘The Song Of Lunch’, and even then I was only able to see the Emma Thompson and Alan Rickman TV movie version. It has a somewhat similar quality but as the action, such as it is, proceeds, it injects elements of plot and tension into the story and is much more conventional. It can currently be viewed here.
What makes these different from my own perspective of seeing a fountain in the park and thinking of the plume on Io’s Tvashtar Patera is specificity. I’m looking at the world in a kind of Cartesian way. I see the parabolas described by the water and consider the similarity, which does make me view them afresh, but there are only specific and sparse details and the comparison is with a specific alien environment. This cognitive estrangement can, however, be broadened and make the whole world surreal. I can remember one guy describing the experience of going swimming as stripping naked, putting on a pair of turquoise pants and immersing himself in a bluish liquid in a large blue room with various other similarly-attired people, and this is indeed surreal, and is more general than the constrained and sporadic examples I’ve mentioned above.
Neurodiversity has sometimes been described as being on the wrong planet, and there’s a website, wrongplanet.net, with this name. But which planet is wrong? Maybe it’s this one. “We” who are neurodiverse might be on a planet which, as a whole, treats us badly and makes assumptions which the rest of us will never be able to guess. This planet could be morally wrong. However, that’s unfair. In fact it isn’t the planet which treats neurodiversity so much as Homo sapiens. And the planet we come from isn’t wrong either. It’s actually the same planet: a conjoined twin Earth with as much right to life as Neurotypical Earth.
That brings us to the Véronique Sanson «chanson» quoted above. The line from Kiki Dee’s English version of the song has always puzzled me – “I feel the rain fall on another planet”. It comes across as a complete non sequitur. Sarada says I’m overthinking it. The original makes more sense: I have undergone such a life-changing experience that I am sensitive to the whole Universe. Now I have a grandchild (and a teenage grand-niece as of the other day, incidentally, which makes me feel really old), and I’m not comparing the experience of considering the Solar System’s other worlds in their own right to losing one’s virginity, but yes I am. I haven’t undertaken a project as grand as the so-called “Grand Tour” because all I’ve done is sit in the living room and typed stuff about the likes of Enceladus, but even that relatively mild enterprise has changed the way I see the world, and we all know about the Overview Effect, so who knows what would await us out there culturally or psychologically if any of our species crossed the lunar orbit?
I was going to blog about the larger asteroids at this point, but in recent days it’s been borne in upon me that there’s a current issue in astronomy, perhaps over-emphasised but definitely there, over whether Pluto was unfairly demoted. The reason I mention this now is Steve’s comment about what the difference between Phobos and Deimos and asteroids might be. It’s a very good question and I’ll address this first.
Phobos and Deimos, the moons of Mars, are a little puzzling. There are two hypotheses about where they come from. One is that they’re main-belt asteroids which were captured by Mars. At first glance this sounds very sensible and logical. After all, Mars is next to the asteroid belt, it could be expected to gather up a few stones from it from time to time and the pair seem to be only the latest representatives of a whole series which have scarred Mars with chains of craters as they broke up and impacted. However, there are problems with it. Firstly, the common type of asteroid found near the edge of the belt closest to Mars is different from the type of asteroid Phobos and Deimos would be if they are asteroids. That type is found near Jupiter. This is due to the inner belt being warmer than the outer belt, so the composition differs because temperature makes a difference to them. Secondly, both moons have almost perfectly circular orbits over the Martian equator, and if they were captured, they would usually have come in at a high angle to the equator and have markèdly elliptical orbits. This can be seen with Nereid, Neptune’s third largest moon, and Saturn’s moon Phoebe orbits backwards compared to most other bodies in the system. Therefore, if Mars’s moons are asteroidal in origin, something needs to be evoked to explain that. A simpler explanation would be that they emerged from the cloud which was forming Mars. This would be spinning in the same plane as any moons which formed from it, and if they were formed in situ they would be more likely to have almost circular orbits. However, as Steve astutely pointed out, the actual nature of the bodies themselves is very close to being asteroidal, and in fact is asteroidal, so maybe it doesn’t matter in most ways. In the sense of the physical nature of the two moons, they basically are asteroids. The way in which they aren’t is to do with their history and orbits, which may not be a sensible thing to focus on. The only thing which goes against this is that both are directly affected by orbiting Mars. Phobos has streaks because of the tidal forces of its planet, and Deimos accumulates fragments and dust from itself as it moves through its rather short orbit. If they were orbiting in the asteroid belt itself, neither of these things would be happening. All that said, I can totally see the argument that they are in fact just asteroids in an unusual place which are also moons rather than minor planets. So I agree with you Steve.
This connects to a wider issue which affects Pluto, and it also affects a number of other worlds in the system which if addressed could solve the problem of knowing what to call the big round things in our Solar System. It could also address the peculiarity of our own “moon”. The 2006 CE definition of a planet by the International Astronomical Union is:
The IAU members gathered at the 2006 General Assembly agreed that a “planet” is defined as a celestial body that
(a) is in orbit around the Sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
(c) has cleared the neighbourhood around its orbit.
This definition was motivated by the discovery of a number of relatively large trans-Neptunian objects. Eris, discovered at the start of the previous year, has now been established to have a diameter of 2326 kilometres and a mass of 1.6466 x 1022 kilogrammes. Sedna, discovered in 2003, has a diameter of around a thousand kilometres and an unknown mass because unlike Eris it seems to have no moons. Sedna is less of a threat to the status quo but Eris was initially thought to be larger than it has now turned out to be. For comparison, Pluto is 2376.6 kilometres and it has a mass of 1.303 x 1022 kilogrammes, so it’s actually slightly larger than Eris but also less massive, so the question arose of whether it would be acceptable to admit a potential host of newly discovered planets, thereby reducing the “specialness” of planets, or to invent a new category. This last idea, of “dwarf planets”, seems very odd to me because the category of “minor planet” had existed for a very long time up until that point and instead of inventing an entirely new class of object, it would’ve made more sense, if they were going to do this. Whether or not I agree with the decision, there seems to be no merit in creating a whole new category of “planet” when “minor planet” already existed. I honestly don’t know why they did this.
Many people have disagreed with the decision to demote Pluto. It did elevate Ceres, previously considered a mere asteroid, at the same time. Before that point, for most of its history since discovery Ceres was considered an asteroid, but it’s the only body in the asteroid belt which has managed to make itself round due to its own gravity (there might be other bodies which just happen to be round-ish through chance because asteroids are irregular and could hypothetically be many shapes, including spheroidal), so it probably does deserve special recognition.
In spite of this definition, which is quite unpopular, a paper has recently been published on the subject arguing that Pluto, among other worlds, does in fact merit planethood. The paper can be found here. It’s sixty-eight pages long and I haven’t read the whole thing but the general gist of it seems to be that there used to be a scientifically arrived-at understanding of what a planet was, but over a period in the early twentieth century when astronomers focussed more on what was happening outside the Solar System, the popular uneducated public understanding of what a planet was took over. I have to say this doesn’t reflect my perception of what happened based on my knowledge of astronomy. I’m aware of the controversy about the canals, the discovery of Pluto, the idea that Mercury always faced the Sun and so on, all ideas which resulted from astronomical research at around that time. I’m aware of the research that was being done at the time about stellar evolution and the realisation that there were other galaxies, but it really doesn’t seem like they were concentrating that much on that more than this Solar System, but anyway, that’s what this paper claims.
Further, it claims that because they adopted a kind of folk understanding of what a planet was, it had led to them adopting earlier, non-scientific ideas about it. So for example, the public was really into astrology and had only recently got used to the idea that the Sun was at the centre of the Solar System rather than Earth. The authors of the paper give examples of how scientific classifications differ from public ones. For instance, most people think of fruit and vegetables as two different things but when it comes to botany, vegetables include fruits, which are the reproductive organs of plants, so from a culinary viewpoint fruit and veg are separate but scientifically they aren’t. To this I would add a couple of things which are I hope relevant to astronomy. One is that I think of a lot of things as fruit, such as tomatoes, aubergines, courgettes, peppers and tomatoes, which other people seem to think of as vegetables because it makes sense to me to think of them nutritionally and in terms of flavour in that way. The other is that the culinary arts are also sciences, and it seems a bit hierarchical to see them as inferior to botany for some reason. After all, we all need to eat. Applying that to astronomy and planets, that would mean that although some things are planets and some things aren’t according to astronomers of a particular vintage, that doesn’t mean there isn’t another branch of science which would view them differently. For instance, everything is subject to the laws of physics, and geology would seem to apply pretty much equally to planets, moons and asteroids in their own way. They’re just bodies in space like everything else. Therefore, I’m not convinced about this. Also, the general public were specifically irritated at the idea of Pluto not being a planet any more, so I don’t see how exactly they were using the public view of what planets were if they managed to annoy so many non-astronomers with their assertion that Pluto wasn’t one.
What seems to have happened is that the problem crept up on astronomers and they kind of panicked and made a fairly slapdash and hasty decision. As various large bodies were discovered on the edge of the Solar System, they became uncomfortable with the idea that they were probably going to end up with a very long list of planets, which seemed unwieldy and not very “neat”, and they also perceived it as an imposition on education that people were going to have to learn about so many worlds. They seemed to feel like this would be regarded as off-putting. The paper compares the situation with how mammals are defined. The official definition of a mammal is now rather abstruse, because it actually hinges on how many bones are in the jaws and the ears, but this is partly because of the need to identify fossil mammals. The widely-used definition is “animals who suckle from their mothers as infants, maintain a different body temperature from their environment, are often covered in fur or hair and mostly give birth to live young”, and the first criterion is the most important. There are exceptions to most of these. For instance, some hibernating mammals don’t keep their body temperatures above their surroundings and humans, whales and elephants are largely hairless, but this is a fairly good definition. However, claim the authors, astronomers have taken a weird approach to planets, having concentrated on whether they dominate their local region, which is in any case vague because what’s local? They’ve also looked at how they move. If mammals had been defined in this way, as warm-blooded vertebrates who walk in herds on land for example, a lot of mammals would’ve been excluded. Bats and whales would then not be mammals and any mammal who has a largely solitary life, such as leopards or sloths, would not then count as mammals either.
Looking at the history of the idea of planets, for a long time any round object in the sky which didn’t appear to stay in the same place was a planet. This used to include Cynthia and the Sun, when people thought Earth was at the centre of the Universe, and it didn’t include Earth. Later on, the four largest moons of Jupiter were discovered and also referred to as planets, and even the thick parts of the rings on either side of Saturn due to the poor quality of telescopes at the time. Later still, Ceres was called a planet because it seemed to fit into Bode’s Law, and turned up where it was expected. By that time, however, the known satellites had been relegated to moons, and soon after Ceres was also demoted because it was realised that there were thousands of other bodies between Mars and Jupiter, some even quite large.
The 2006 definition also has a rather silly consequence which a few people have noticed: it means Earth isn’t a planet! As I’ve mentioned before, from the Sun’s perspective Cynthia doesn’t orbit Earth, but the two weave in and out of each other’s orbits. I’m not completely clear what the astrological influence is supposed to be, but I think it’s the emphasis on orbits, i.e. the kind of definition which would’ve excluded bats, whales and leopards from being mammals. Whatever the definition of a mammal is, it seems to make more sense to use their anatomy and physiology than other more dubious criteria. Both of the definitions I mentioned above do this. The first is rather abstract and strange to most people, although there are good reasons for it – mammal jaws and teeth survive better than the rest of their bodies so it’s like identifying a body by dental records – but both of them focus on what their bodies are like, which seems entirely sensible compared to that fictional other definition.
What, then, is proposed as a more sensible definition of a planet? Well, it’s closer in spirit to that way of defining a mammal. A planet is a geologically active body. I have to admit I’m not sure about this because of various things, such as “eggshell planets”, and I’d also want planets to be round and I can’t tell if they also stipulated that. What it means (I’ll get back to eggshell planets in a moment) is that Pluto’s Sputnik Planitia which is created by frozen nitrogen and is active even though the Sun isn’t strong enough at that distance to have that effect. In talking about asteroids, I’ve mentioned the fact that the larger ones tend to be layered like Earth is, but the smaller ones are either rubble piles or mixtures of different minerals and other substances which aren’t separated out in the same way. A geological process has done this sorting in the larger ones, and consequently Ceres, for example, could count as a planet: it has been geologically active.
This applies also to some moons. Io, the innermost large moon of Jupiter, is intensely active with continual volcanic eruptions, to the extent that it’s thought to “turn itself inside out” every few years – some much of its interior is spewed onto the surface that the former surface becomes the interior and proceeds to get thrown out itself a few years later. This is because of the tidal forces effectively “wringing” the moon all the time, with the other large moons in the Jovian system along with Jupiter itself wreaking havoc on the place. By this standard, Io is definitely a planet, albeit a planet which is also a moon.
I’ll now permit myself a digression into eggshell planets. An eggshell planet is a surprising kind of “planet” which kind of “does nothing”. It isn’t necessarily possible to tell from a distance which planets are like this. Earth’s crust is divided into plates, and other planets have a thick, solid layer all the way round, but there is another possibility or which at least three examples may have been found already. This is where the crust is thin and fragile, and so cannot have plates or thick layers, and also can’t even support mountains or hills, so the surface is solid and also smooth, and nothing happens there – no volcanic eruptions, continental drift or erosion, because there’s nothing to erode. The question arises of whether this even counts as a planet under this new definition, since it isn’t geologically active. However, there are no such planets in our Solar System as far as anyone knows, and they’re probably quite rare.
There are three categories of planets suggested in this new definition: terrestrial planets; giant planets; satellite and dwarf planets. The last category is the largest. It includes the large moons of Jupiter, Ceres, Titan, Pluto, Charon, Eris and Sedna, and in fact there are more than a gross of these. Far from the expected response, apparently people tend to be quite excited at the idea that there are so many planets around the Sun. The giant planets include Jupiter, Saturn, Uranus and Neptune, so no surprises there, although this clear-cut division may be an artifact of how our own Solar System is, with its complete absence of the very commonest type of planet, the mini-Neptune, intermediate between Earth and Neptune in size.
There are five planets in the terrestrial category rather than four, because once the criterion for dominating its orbit has been removed, Cynthia becomes eligible, which makes me very happy! Cynthia is not even in the same group as the satellite and dwarf planets, but a planet just like Mars and Mercury. This also means that the Apollo astronauts landed on another planet, not just our moon. As well as that, Earth now has no moon!
It seems that the process leading to the decision to redefine planets was not very scientifically grounded and was in fact rather acrimonious. The orbital dynamics people took umbrage at the geophysical definition and there were only a few days available for debate, forcing people to take sides quickly without due consideration. Planetary scientists were underrepresented because they’re apparently not officially astronomers, which is a bit astonishing. Another motivation was to keep the number of official planets low because the IAU didn’t expect the alternative to go down well with the public because previously, i.e. in Victorian times, they’d felt more comfortable with a small number of planets. They were used to seven at that point, including the Sun and Cynthia. This is probably no longer the case, so in 2006 they made a decision based on misjudging the mood of the general public.
To finish, I’m going to make a commitment. Henceforth I will be referring to every spheroidal body in the Solar System as a planet, although I will also acknowledge what kind of planet it is, such as a moon or dwarf planet. And Pluto is a planet!
There’s something very odd about our history with the moons of Mars. I also realise I’m not strictly sticking to the practice, as far as possible, of moving outward from the Sun to the edge of the system by putting this post after the one on the asteroid belt, but you kind of needed to know enough about the asteroids before I started to talk about them, plus everything’s whizzing around all the time anyway so who’s to say what order anything is in?
The weird thing about Phobos and Deimos, “fear” and “panic” as befits moons of the Red Planet, the planet of war, is that some people seemed to know about them before they were discovered. In 1752 CE, Voltaire wrote «Micromégas», a short story in which aliens say that Mars has two moons. The reasoning here is that Venus has no moon, Earth one and Jupiter four, so Mars could be expected to have two, and possibly Phæton three. It has been claimed that the largest asteroids are in fact that planet’s old moons, but I digress. It also seems to imply Saturn would have five. However, Voltaire may also have been influenced by Jonathan Swift, who made an even more remarkable claim about them in 1726’s ‘Gulliver’s Travels’. In his voyage to Laputa, the floating island sometimes interpreted as a huge flying saucer, the inhabitants are said not only to have discovered two Martian moons but well, here’s the quote:
They have likewise discovered two lesser stars, or satellites, which revolve about Mars; whereof the innermost is distant from the centre of the primary planet exactly three of his diameters, and the outermost, five; the former revolves in the space of ten hours, and the latter in twenty-one and a half; so that the squares of their periodical times are very near in the same proportion with the cubes of their distance from the centre of Mars; which evidently shows them to be governed by the same law of gravitation that influences the other heavenly bodies.
– Voyage To Laputa, Gulliver’s Travels, Jonathan Swift 1726.
In fact Phobos orbits Mars in seven hours and forty minutes whereas Deimos takes thirty hours and twenty minutes, and the distance of Phobos isn’t far off being right either. Nobody knows how he did this. The moons weren’t discovered until 1877. The fact that both Voltaire and Swift mentioned the moons has led to many of the features on their surfaces being named after them and their works, and there’s also the issue of Asaph Hall. Hall was busy trying to discover the moons of Mars once and became disheartened, so he went home and complained to his wife. She took issue with this and encouraged him to go back to the observatory and not to come back until he’d discovered them. They succeeded, and consequently Phobos’s largest crater is named Stickney, after her maiden name, whereas only its second largest is called Hall.
Although the idea is now rejected, the notion that the further out a planet is from the Sun does have its merits. The Hill Sphere of a planet of a given mass will be greater the more distant it is from the star it orbits. This is the region where the planet’s local gravitational influence exceeds the Sun’s. Hence one might indeed expect Earth to have one moon, Mars two, Phæthon three and Jupiter four, although in fact Jupiter has many more than that and only has four large moons and Phæthon disnæ exist. It isn’t entirely absurd though. A similar concept to the Hill Sphere is the Roche Limit, which is the minimum safe distance a large solid object can approach a body without tidal forces ripping it apart. This is 2.44 times the radius of the larger body, and in Mars’s case this is 8 270 kilometres from the centre or 4 880 kilometres above its surface. The actual distance of Phobos from the centre of Mars averages 9 377 kilometres and is therefore not that far off the limit. It also orbits more than once a sol (Martian day), which causes it to be pulled about by Martian tidal forces and its surface is therefore streaked where Mars has been clawing at it. It will collide with the planet in the next few dozen million years, probably around the time the shovel-horned gigantelope becomes extinct. Nor is this the first time it’s happened. There are chains of impact craters around Mars near the equator which suggest other moons have suffered the same fate. As I’ve mentioned before, Mars may have rings in the future and have had them in the past too.
I’m very inclined, unlike the moons which is an argument against what I’m about to say, to believe that both moons are captured asteroids. Against this is the fact that their orbits are close to being circular and their proximity to the plane of the Martian equator, which suggests they were formed with Mars. If this is true, there is a problem in the fact that we happen to be living at a time within one percent of the planet’s history of Phobos crashing into it, but it’s possible that there were more moons in the past and that this has happened on a regular basis. This resembles Hans Hörbinger’s belief (he’d probably like it to be called a theory but I’m not sure it is) that we’ve had a series of icy moons which crash into us periodically, causing ice ages. I’ve even wondered if the reason there isn’t more complex life on the planet is nothing to do with conditions there generally so much as the possibility that it constantly suffers major impacts with bodies several times as massive as the Chicxulub Impactor. On the other hand, and I don’t want to go on about this too much, it’s also been suggested that Mars is a better place for life to have begun than Earth, so maybe one of these impacts sent life-bearing meteors to Earth and those moons are the reason there’s life on Earth in the first place.
Just to fill in the details, both moons are somewhat irregular although Phobos is unusually close to being spherical for such a small moon. Both are probably carbonaceous chondrites, that is, stony but with a fair content of organic compounds in them. Both have almost circular orbits. Phobos is 20 x 23 x 28 kilometres in size and Deimos 10 x 12 x 16, so both are smaller than the Isle of Wight. Phobos has a mass of 9.6 x 1015 kilogrammes and Deimos 2 x 1015 kilogrammes. Both have a density around twice that of water, which makes them the least dense of all the planets and moons in the inner Solar System. From the Martian surface, Phobos crosses the Sun an average of around twice a day, because since it’s near the equator, the two’s positions coincide quite often. Its width is about a third of the Sun’s, which emphasises how close it really is as the diameter is less than a hundredth of Cynthia’s. It’s about as bright as the morning star, but is invisible from within the polar circles. Deimos stays above the horizon for a day and a half at a time and is visible closer to the poles. It’s about as bright as Vega. Both of them are dark compared to Cynthia, and in fact darker than most of the asteroids in the inner belt. Carbonaceous chondrites are more characteristic of asteroids near the orbit of Jupiter, and this suggests that that was where they originated. Their escape velocities are so low that it would be possible to run off the surface.
On Phobos the largest crater is Stickney, at ten kilometres across. This is a considerable fraction of the moon’s diameter. Due to the low escape velocity, there are no ejecta around the craters as they would just be flung deep into space without any chance of recapture. The aforementioned grooves are about half a kilometre wide each, but they may turn out not to be solid grooves in a hard surface because of the smallness of the moon. Both moons are likely to be rubble piles rather than solid objects. They’re also likely to be undifferentiated for the same reason – their gravity is too weak to pull constituents of different densities into separate layers.
I haven’t done the maths on this, but I think Mars has the smallest total mass of satellites of any planet in the system which still has moons at all. This puts the three bodies taken together at the opposite end of the scale from Earth and its companion, which is the largest total mass compared to the planet.
I haven’t said much about Deimos yet. It has two craters on it called Swift and Voltaire, which are at the corner just before the terminator near the centre of the picture. This photo shows how the craters don’t really have rims in the same way as they do on larger bodies, or central peaks. They’re just dents. The moon looks smoother than Phobos and is less subject to the tidal forces which affect the other moon, and its craters are also smaller. Although the ejecta are not recaptured by gravity immediately after impact, Deimos is moving through a ring of them and gradually accumulates them, leading to its smooth appearance. That’s the accumulation of small particles such as dust which were originally part of the moon. I’m guessing that this means the leading half of the moon is different than the “leeward” side but I don’t actually know. This is the case with some other moons, particularly Iapetus.
I also feel like whereas Phobos is temporary, Deimos is permanent. I think Mars has got through a load of other moons which have ended up breaking up into rings and strewing its surface, the next of which is Phobos, but Deimos has always just quietly got on with things over the æons. This is because Deimos orbits further out and seems to be stable, whereas Phobos, as well as everything else, is being braked by the upper atmosphere even though it’s really far out in that respect and the Martian atmosphere is very thin compared to ours. Another aspect of Phobos and other moons constantly hitting Mars is that considering it’s a carbonaceous chondrite, it will end up, as others may have done, contributing organic compounds not that far off from biochemical ones, and maybe the same has happened here, resulting in the emergence of life, maybe there, maybe here, or maybe there before spreading here.
There used to be a popular fringe idea that Phobos was a space station, possibly because it seems to be unstable over a long period of time, and it was also thought to be even less dense than it is now thought to be, suggesting it was hollow. Maybe it is kind of hollow, in the sense of being “spongy” – consisting of irregular boulders which don’t fit together neatly, making it porous and riddled with caves all the way through.
Right, that’s all I’ve got to say about Phobos and Deimos, except that my brother used to share his house with two cats of those names. Deimos was black, just like the moon is darkish. Next time: Ceres (or maybe several of the largest asteroids).
This image makes me sad. Not only have I had to shoehorn it in under a flimsy “fair use” justification but in today’s long-since won victory of raster scan over vector, it doesn’t deserve this low resolution. I shall digress immediately from the main topic!
Here’s the thing, unappreciated by the youth of today. There was a time when there were two main ways of producing a graphical display on a cathode ray tube. There was, incidentally, a third way, which was actually the first historically, where character stencil anodes provided alphanumerics which were then placed on the screen using electrical fields to deflect the beam to the appropriate location, but this seems to have gone out of fashion in the 1960s CE. This is an extension of this experiment, dating from the nineteenth century:
It may not be exactly fair to describe it as a war, but the alternatives were to transmit signals to a relentlessly horizontally scanning electron beam alternately producing odd and even numbered lines or to steer the beam using X- and Y-axis electric plates to draw images on the screen like an Etch-A-Sketch. The latter system required a high-persistence phosphor – the glow from the substance coating the screen had to fade more slowly than it would’ve done on a telly or the images wouldn’t stick around long enough to be visible. These are raster and vector scan respectively. Vector scan has two advantages. It doesn’t need fast processing power or a lot of memory to store the image, and it has effectively infinite resolution. There’s no such thing as a pixel in the vector scan universe. Raster scan usually needs constant feeding by an overworked CPU or CRTC (cathode ray tube controller), usually with a frame buffer storing the image. The only exception I know to this approach was the Atari 2600, which had the 6507 CPU directly control the electron beam frame by frame, which makes me tired just thinking about it but was a necessity for a machine with only 128 bytes of RAM.
Anyway, in 1979 Atari brought out an arcade game with a different approach from the likes of ‘Space Invaders’ because it used vector scan. Every object on the screen was redrawn something like sixty times a second, including the player’s ship, the flying saucer, the missiles, the asteroids themselves and even the broken up rocks from the zapped former asteroids. I can’t help feeling there may be a link between the unusual techniques which must’ve been used to get their home console to do anything at all and Atari’s use of a vector scan monitor for ‘Asteroids’. Just imagine, though, trying to make a word processor that way, drawing something like two thousand alphanumeric characters on the screen every twenty milliseconds. Just ain’t gonna happen, particularly if all you’ve got is a Z80. It’s still a shame though.
I presume there’s a link between the asteroid field scene in ‘The Empire Strikes Back’ and this arcade game. They would’ve been developed at practically the same time, and both portray asteroids as fairly slow-moving but still deadly giant irregular rocks which hang around in crowded groups. In reality, asteroids are nothing like this. There was some concern when the first spacecraft were sent through the asteroid belt to Jupiter and Saturn that they were going to get clobbered by the rocks, but in fact that was a pretty remote risk. The belt contains up to two million asteroids at least a cubic kilometre in size, but the belt itself is enormous in extent. If considered to stretch all the way between the orbits of Mars and Jupiter, that’s five hundred and thirty million kilometres. It’s often inappropriate to consider space two-dimensionally, but this doesn’t apply so much to the asteroid belt as most of them orbit within a flattened region like the rest of the planets in the system. This gives it an area of 76 AU2, or 1.71 x 1018 square kilometres. Scatter two million planetoids on a plane that size and each will have on average 8.55 x 1011 square kilometres to itself. This means that every asteroid can be expected to be almost a million kilometres from its next-door neighbour most of the time. The brightest asteroid is Vesta, with a magnitude from here of 5.1 at a distance of just over one astronomical unit, but this is far brighter than the majority. I haven’t done the maths but it seems reasonable to suppose from this that on the whole some asteroids would be visible to the naked eye from each other most of the time, mainly in the ecliptic (the plane of the solar system (actually Earth’s orbit but the two are close to each other)). But seeing a rock one kilometre across from a million kilometres away means they’d be unlikely to show a visible disc even through an ordinary telescope, and many asteroids are quite dark anyway. Hence most of the depiction of asteroids as occupying a hazard-strewn field with enormous irregular boulders within spitting distance of each other is confined to the realm of fiction, but there is one aspect of this image which is realistic. Asteroids are often piles of loosely-bound rubble which easily but often temporarily come apart with relatively little force.
The asteroid belt may not be neat in itself, but it does neatly divide the inner and the outer planets. Two very different ways of looking at the Solar System are that it consists of the Sun, Jupiter and assorted débris, and that it consists of the Sun, a belt of millions of rocks and a few planets and moons. This post will consider it in the latter manner. Almost every body in the system is an asteroid orbiting between Mars and Jupiter. Then there’s a smaller class of asteroids orbiting elsewhere but even these taken alone dwarf the number of moons and planets. There are also centaurs, but I’ll come to those in another post.
Are asteroids boring? Well, they’re generally small clumps of solid matter which don’t do very much most of the time. They don’t have the grandeur of the major planets and they aren’t beautiful, bright or colourful to most human eyes. A lot of them look rather like cratered potatoes. The first of them, Ceres, was discovered on the first day of the nineteenth century by Giuseppe Piazzi. It appeared to obey Bode’s Law, so he looked in the right place for it. Up until that time there had been a suspicious gap between Mars and Jupiter which “ought” to have had a planet in it. However, soon after its discovery it emerged that it was only one of many, thousands and nowadays millions of other bodies, referred to as minor planets. This is worth remarking upon because before the concept of the dwarf planet was invented, bodies orbiting the Sun were divided into comets and major and minor planets, so the category already existed and was in widespread use and it’s a bit strange that they decided to change that. Pluto could just be reclassified as a minor planet and be done with it.
Piazzi was working alone. He was not part of a group of five sponsored astronomers called the “celestial police” who were looking for the missing planet at the same time. The next three, Pallas, Juno and Vesta, were all found by 1807. Of these, Vesta is bright enough to be visible to the naked human eye on occasion. There was then a long gap before the next, Astræa, was found in 1845, by which time all the original discoverers had died. All the early asteroids have feminine names, and many were taken from mythology, but there ended up being so many of them that all the names were used up. Some of them are also doubled-up from other bodies, such as Ganymede. Many of the names are quite peculiar, such as Ekard, which was discovered by someone at Drake University, Hapag, named after a steamship company, and The NORC, which was a custom-built computer used to calculate the orbits of minor planets. Nowadays they’re often named after famous people such as Patrick Moore and Terry Pratchett.
Early on, it was conjectured that the asteroid belt was a remnant of a planet which had been broken up by a collision, named Phæthon, with which another planet sometimes called Marduk had an encounter. I was very taken by this as a child, to the extent that I imagined it was habitable but cold and settled by Homo erectus – you might remember I had an elaborate theory that humans had had a Galaxy-spanning civilisation hundreds of millennia ago. However, there is nowhere near enough mass in the belt for this to work. The total mass there is less than that of Pluto, and most of it is taken up by Ceres. What probably happened is that the asteroid belt is a relic of the early Solar System. The whole of the inner part of the system was probably initially a much more crowded disc of asteroids. Whereas in some places it was possible for the asteroids to coalesce into planets, helped by Jupiter’s gravitational shepherding, right next to the planet it was too disruptive for any other planets to form. The fact that the asteroids are much smaller than planets also means they’re likely to be a more accessible source of metals, particularly heavy metals, which tend to sink to the centre of larger bodies. This makes the asteroid belt potentially very useful. It’s almost literally a gold mine. I mention this not to emphasise the potential money which could be made, but to stress the utility of a potential resource which could be beyond the reach of capitalism. There is also the issue of whether we have the right to interfere with them at all. Maybe instead we should pursue technology which doesn’t require the use of these elements.
The belt is not entirely immune to the gravitational influence of Jupiter. Like the rest of the system, asteroids whose orbital periods are in harmony with the giant planet, such as 2/7 or 5/9, have been steadily pulled towards it at closest approach, forming what might be described as bands or clumps of rocks. The biggest of these is the Hecuba group, the penultimate one counting outward, which has a mean period of around six and a half years. The groups are named after their most prominent members and are, in order from innermost to outermost, Flora, Hestia, Minerva, Hecuba and Hilda. It’s misleading, though, to think of them as bands as such, because asteroidal orbits generally are quite elliptical and it’s entirely feasible for an asteroid belonging to one group to be in the territory of a completely different one. The mean distance from the Sun determines the period but the eccentricity and inclination can be almost anything, so whereas these groups exist, they don’t necessarily correspond to clumps which would show up if a chart of the instantaneous position of bodies in the belt at any one time were to be plotted.
It isn’t all about orbits of course, but it’s worth mentioning one final orbital peculiarity which occurs in the belt: that of Hidalgo. Like Icarus, Hidalgo’s orbit is more like that of a comet than a planet. It’s very tilted compared to planetary orbits at 42° and swings from the inner belt out to near the orbit of Saturn in a fourteen-year cycle. It has a diameter of fifty-two kilometres, and seems to be a centaur rather than an asteroid, although it “lives” in the belt for much of the time. It was discovered in 1920, which would make it the first centaur to be found, sixty years or so before Chiron.
Asteroids, particularly the smaller ones, are often not solid objects but clusters of rocks and dust held together loosely by their rather low gravity. They can sometimes be solid, such as if they’re larger as with Ceres or melted together due to close approaches to the Sun. This fragile condition has a number of consequences. It means that simply bombing a Near-Earth Object may lead to it temporarily distintegrating and then reassembling, besides the problem of a large number of smaller objects pelting the planet rather than one large one. More benignly, it means that many asteroids have their own moons, are practically double or can be dumbell-shaped, i.e. effectively two asteroids in contact with each other. Some are also ringed.
Composition-wise, there are different classes of asteroid. Some meteorites are former parts of asteroids, so in this case we have samples available right here. They can be metallic, carbonaceous, stony or icy, or mixtures of these. The most common class consists of clay and silicate minerals, making them closest to what we might think of as rocks. These are known as the C-type, for “chondrite”. S-types are stony, made of a mixture of nickel-iron and silicates. Finally, the metallic, or M-types, are mainly nickel-iron, like Earth’s core. Composition is partly dependent on distance from the Sun because of temperatures. The larger asteroids will have layers of different composition like a planet, whereas the smaller ones will be more mixed. There are also “vestoids” or V-types which are like Vesta. Vesta is somewhat unusual among the minor planets and only about six percent of the belt consists of these bodies. They’re unusually bright for their size. Some of them have orbits which suggest they’re physically associated with Vesta in some way, but not all. Diogenite meteorites are V-type, and are more like the kind of rocks found on Earth. Note that there’s a difference between “what we might think of as rocks” and the rocks we’re actually familiar with. Diogenites have undergone melting and cooling before entering our atmosphere and are also known as HED meteorites, for “howardite-eucrite-diogenite” after their main subtypes. When Vesta is hit by another body, chunks of its crust fly into space. If these reach the region of the belt where it takes about four years to orbit the Sun, which is two and a half AU from it and incidentally about the closest Ceres gets to the Sun. This is an unstable orbit due to Jupiter and over something like a hundred million years some of them become NEOs instead, and some of those actually reach Earth’s surface. In the meantime, some of them remain asteroids. Some are from deeper inside Vesta and rich in olivine, a mineral found on Cynthia.
It’s possible that rocks and the like bore most people. Eddie Izzard has a routine bemoaning how boring the exploration of the Solar System is because so much of it is basically about rocks. Since I’ve committed myself to avoiding the subject of life elsewhere, I’ve also kind of confined myself to such boring topics. A lot of planetary science is bound to be about rocks and minerals. Technically, many meteorites and therefore asteroids are not actually made of rocks at all, but for now I am, I’m afraid, going to talk about another kind of rock. I dunno, is this boring? I don’t think it is. Maybe it’s my job to excite you about these rocks.
Chondrites are stony and not modified by melting or differentiation, which is where different layers settle out, as happens on larger bodies. Something like six out of seven meteorites are chondrites, so it can be presumed that most belt asteroids are too. They formed when dust and grains of rock accreted in the early Solar System. They contain spherical objects called chondrules, which are solidified molten drops of rock. Perhaps surprisingly, some of them also contain minerals altered by water, but when you consider that water is the most abundant compound in the Universe this becomes less astonishing. There are also achondrites, which are basalt-like rocks with no chondrules. A fairly rare but significant type of chondrite is the carbonaceous variety, which contains organic compounds such as amino acids, as found in living things on this planet. Although chondrites generally are defined as low in metals, they may still have inclusions of metal within them.
Nickel-iron asteroids, also know as M-type, are presumed to exist as there are plenty of asteroids which have this kind of reflection spectrum. They include Psyche and Lutetia and can have a density as high as eight times that of water. The density of asteroids can be judged sometimes by how they influence spacecraft via their gravity or any moons they might have, or just concluded from their appearance. Psyche, with a diameter of 222 kilometres, is the largest M-type and is due to be visited by a space probe in 2026.
Around one asteroid in six is S-type: “stony”. The inner belt consists mainly of these and they become less common towards the orbit of Jupiter. Juno is an S-type, with a diameter of around two hundred and forty kilometres. They’re mainly silicates of magnesium and iron. Talc is a form of magnesium silicate, as are some forms of olivine, and iron silicate is the other extreme of olivine, which has various concentrations of magnesium and iron.
Many of Jupiter’s moons are in fact pilfered asteroids, as are the Martian Phobos and Deimos. In general, asteroids are more accessible to human inspection than most of the rest of the Solar System because many of them cross our orbit and fall on us in the form of meteorites, and space missions can also be sent to them fairly easily.
I’ve decided to leave Ceres and possibly some of the other larger asteroids in the belt until another post, because they’re large and atypical, more like planets than asteroids really. However, if Ceres is excluded, there are no asteroids both large enough and made of the right materials to be approximately round, exclusing them from the definition of planet.
I’m revisiting this. A few mirs ago (I’ll tell you about that in a bit) I made a Martian calendar for the mir 214. I used the Darian calendar with the Rotterdam month naming system. This brings up the first issue: Mars cannot have real months because its moons take around eight and thirty hours to orbit, and its day lasts less than twenty-five. Therefore the subdivision of the mir – the Martian year – is fairly arbitrary although it can be more freely divided than if it had meaningful moons.
The compilation of the Martian calendar proved to be a bit nightmarish. I bought a new printer to produce the colour illustrations of the pages, and used the trusty old monochrome laser printer to do the rest. The latter did absolutely fine. The former was an inkjet, and reports of its capacity turned out to be a big overestimate. Since I’d worked out the price point based in that capacity being true, I ended up making a loss on every copy. Because of this, I ended up flinging the printer forcefully into the pantry in a fit of rage. Something has really got to be done about the scam that is the inkjet printer, but that’s another topic.
Due to the research I’d had to do to prepare the calendar, the point came when I felt probably more familiar with Mars than I am currently with Antarctica. I began to get a real feel for the planet which I don’t even have for Cynthia, and certainly more than any other planet or moon apart from Earth. It’s kind of like a cross between Cynthia and Earth. Alternatively, it could be looked at as an extreme version of Antarctica without the ice, or a dwarf version of Earth. Its terrain is divided into highlands and lowlands, with one largely monolithic example of each, meaning that unlike Venus with its several plateaux and similar size to Earth, it or Earth with its connected but somewhat separated oceans and six continents, it can be thought of as having a single continent and a single ocean, having in toto a surface area almost exactly the same as the total land surface of our own planet. However, it has a thicker crust and no plate tectonics. This is demonstrated by the area known as Tharsis, named after Tarshish, an old name for the Iberian peninsula.
As a child, I used to think Tharsis looked like someone had stuck a fork in Mars. It’s dominated and was formed by a series of volcanoes in a line with the largest volcano in the Solar System to the northwest, the famous twenty kilometre high Olympus Mons, previously known as Nix Olympica. These have contributed an enormous shield of solidified lava to the surface which on Earth would’ve become a chain of mountains or islands, as with Hawaiʻi, but because the Martian crust is stationary the rock has simply built up, and the lower gravity has allowed it to rise higher than it could’ve done here, and weigh down the crust to the extent that it’s caused a crack to form, known as Valles Marineris, a giant canyon stretching across something like a quarter of the planet. All of these structures dwarf their counterparts on Earth, and since Mars only has about half Earth’s diameter, they dominate the surface. When it’s midday at one end of Valles Marineris, the other end is in darkness and consequently winds blow along its length.
Here’s a relief map of the planet:
The lower elevations are blue, the higher ones red. Tharsis is the red blob on the right. One feature I haven’t mentioned yet is the great basin known as Hellas, which is the deepest dent on the planet and is almost deep enough to have liquid water at its bottom because of the density of the atmosphere there, although it doesn’t quite get there. This is the purple oval in the bottom right quadrant. It can be seen that if the planet was flooded there would be an ocean in the northern hemisphere plus a large lake in the southern. Maps of planets are quite confusing as the convention seems to have changed. Whereas previously south was at the top because astronomical telescopes don’t bother to turn the image the right way up (extra lens means loss of light), it seems to have changed to putting north at the top.
The regions of Mars have names like Chryse (Gold), Argyre (Silver) and Margaritifer (Mother Of Pearl). There was also a complete revolution in nomenclature due to the discovery in the mid-1960s CE that the canals were optical illusions. Before that, Mars was considered to have canals, previously considered to be “channels” but due to translation the word “canali” became “canals” in English, and its features were named according to brightness. When Mariner 4 flew by Mars in 1965, it was a huge shock to astronomers and other space scientists because of how different, and more hostile, it turned out to be compared to Earth and the presuppositions projected onto Mars and Venus more or less demonstrate that the expected panic and other impact conjectured from First Contact are perhaps overestimated. After all, for something like a century it was popularly assumed that there was complex life on both Venus and Mars and intelligent life on Mars and it didn’t cause societal breakdown. The question arises of whether society has changed in such a way that it now would.
Interestingly, the person who “discovered” the “canals” was a draughtsperson rather than an artist, and later cartographers with an artistic background didn’t produce so many of them because they were trained to draw what they saw. Giovanni Schiaparelli was in fact related to the fashion designer, in case you’re wondering, and appropriately enough canals were all the rage for decades. For old time’s sake I’ll reproduce one of those maps:
I could’ve found a better map but preferred to furnish you with the yellowing and disintegrating ’60s paperback I learnt much of my initial astronomy from, for old time’s sake. Note south is at the top, and compare with a modern map:
This is from here. This is not a very clear image but it’s hard to find a cylindrical projection of Mars. The PDF linked is much more legible. The most prominent feature of all, Syrtis Major, the “great bog”, is visible in both. Acidalia Planitia is also named in the older map as Mare Acidalium. Conspicuous by their absence are of course almost all of the canals. The closest one gets is Valle Marineris. It’s hard to imagine how utterly different things have become since the early ’60s in this respect.
The Martian atmosphere is to ours as ours is to the Venusian one, in that it’s below a hundredth of the sea level density of ours and ours is a ninetieth of the solid surface density of that of Venus. In another way, Venus and Mars have similar atmospheres as both are mainly carbon dioxide. This makes them unlike Earth’s primordial atmosphere, which was mainly nitrogen, but before the outgassing, Venus would’ve had a mainly nitrogen atmosphere and most of Mars’s atmosphere has been lost to space. The pressure at the surface of Mars is about the same as Earth’s thirty kilometres above sea level, but because it’s much thinner and the Martian surface more variable than Earth’s, the gravity being lower, the variation in pressure is much greater, but it never reaches the point where ordinary water can be liquid at all there.
Mars is the only surface as far as I know in the Solar System which has both extensive cratering and signs of water erosion. Usually the two would tend to rule the other out. It has teardrop shaped “islands” and branching river patterns leading down from the highlands to the lowlands, but some of those islands are formed by craters:
Many of the craters on Mars are quite eroded, probably by wind:
Such images were first sent back from the 1965 mission, and have no analogues on Mercury or Cynthia. The rims can be seen to be eroded or partly erased by the movement of sand or actually rubbed out by the process of sand-blasting by the wind. Winds on Mars can reach up to half the speed of sound.
I’ve described the process as sand-blasting. Like describing the Martian regolith as “soil”, this can mislead. It looks like wet sand, but is about as fine as talcum powder, is also high in iron, hence the rusty colour, and like moondust also contains substances which on Earth would have reacted with oxygen or water, which makes the scenario in ‘The Martian’ less plausible. It effectively contains bleach. A substance called perchlorate consists of a chloride ion attached to four oxygen atoms in a tetrahedron, and is negatively charged. It’s toxic to humans, causing lung damage, aplastic anæmia (where the body permanently shuts down red blood corpuscle production) and causes underactive thyroid, for which it’s used as a drug to treat overactive thyroid. However, it can also be burnt to release oxygen and finds use as an oxidant in rocket fuel. Its presence in Martian sand makes it harder to imagine what kind of life could survive there. However, this series is not about life on Mars.
The planet is periodically enveloped in a global dust storm. This actually happened while Mariner 4 was on its way there in ’65, when only the Tharsis volcanoes were visible above the clouds. Carl Sagan was very focussed on this, leading to them being referred to as “Carl’s marks”, but it would’ve been pretty disastrous if the storm hadn’t cleared by the time the spacecraft got there because nothing else of interest would’ve been visible. Maybe the idea of the planet being Earth-like would’ve continued for longer. Again, in ‘The Martian’, the dust storm is portrayed as much more destructive than it would in fact have been because although the wind is very fast, the low pressure means it isn’t very forceful. They happen about once every three mirs, although there are more localised ones in between. Like the possible “mists” on Cynthia, Martian dust particles become statically charged in the process of being blown about and rubbed against each other, leading to them sticking to every available surface, including the likes of solar panels, potentially to space suits and moving parts on landers and rovers. This blocks sunlight from reaching solar cells and makes it difficult to design rovers, which also get covered in the stuff. What happens is that the sunlight warms the ground, leading to a temperature inversion similar to the one causing tornadoes here on Earth and this causes dust devils and ultimately dust storms. They tend to be stronger in the southern hemisphere, which brings up another issue I’ll go into in a minute. A very important consequence of the study of dust storms on Mars, which would justify the Mars missions on its own and emphasises the vital rôle of space exploration, is that a model applied to the Martian atmosphere was applied to our own if it was filled with soot after a nuclear holocaust, and predicted the nuclear winter scenario as depicted in the BBC TV drama ‘Threads’. This seems to have contributed to the end of the Cold War. Whether the prediction is valid has become a controversial issue which I don’t want to cover here.
The Martian orbit varies between 1.666 and 1.381 AU (1 AU=average distance of Earth from the Sun), making it the second most eccentric planet after Mercury. Unlike Mercury, Mars has a fair axial tilt which causes seasons. Due to this eccentricity, the seasons are more extreme south of the equator since the surface is tilted away from sunlight which is already weaker in the winter and towards stronger sunlight in the summer there, and the reverse is the case in the north. From here the most obvious effect is a larger southern ice cap in the winter, which I think I’ve managed to see through binoculars. This eccentricity also makes the seasons different lengths in the different hemispheres.
Frost and “snow” makes Mars seem more Earth-like than other planets. Mariner took photos of frost in craters, which is a rare combination over most of the planet but is found in polar craters on Mercury and Cynthia. This frost, however, doesn’t fall but freezes out of the atmosphere and is dry ice, i.e. frozen carbon dioxide. For a long time it was unclear whether there was real snowfall on Mars, in a couple of respects. It wasn’t clear whether there was water ice in the snow or whether it actually fell or just appeared like frost from the atmosphere, which is almost completely carbon dioxide. It’s now thought probable that water ice snowfalls occur every night of the northern summer. Actual flakes, from high in the atmosphere. That said, much of the ice on the surface is dry ice, and just as dry ice sublimes (turns from solid to gas without melting) on Earth, so does it on Mars. The water ice snow situation is less straightforward because it tends to become dusty, allowing it to absorb heat from the Sun. At night, water ice clouds lose heat to space, causing them to cool, thereby becoming denser and falling towards the ground as snow. The temperature difference leads to winds, which blow the snow around and there are in fact blizzards. There’s also virga – precipitation which doesn’t reach the ground.
Although the amount of water vapour in the atmosphere is tiny compared to Earth’s quotient, the thinness of the Martian atmosphere means it’s still almost saturated and there are therefore water-based clouds there. There are no cumulus clouds – “little fluffy clouds” – but other kinds are present such as cirrus, the ice clouds found high in our own atmosphere. There are also wave clouds, fog and hurricanes. Noctis Labyrintus, the network of gorges west of Valles Marineris, fills with fog every morning. There are also orographic clouds, which are clouds caused by mountains or high ground lifting saturated air past the point where it can still hold all the moisture. Entirely separate from the water ice clouds are the dry ice ones, which form when it’s cold enough to drop below -78°C, the freezing point of CO2. I find this quite odd as it’s the actual atmosphere freezing and snowing. This also happens on Triton, Neptune’s largest moon, where the nitrogen atmosphere freezes and precipitates onto the surface.
Mars has dunes. These have ice on them, but this isn’t always so. These particular ones are unlike Earth’s in that they have a kind of network pattern on them, thought to be due to thawing and subliming. There are also wind-blown streaks.
It’s difficult to know where to stop with this. I acquired a lot of information about Mars when I did the calendar and there’s so much I could mention but I feel this is getting somewhat delayed by me adding to it, so now I’m just going to publish it “as is”. So there you go. Lots more about Mars could be said but that’s it for now.
Space is in a sense mostly empty. In another sense it really isn’t because there are virtual particles everywhere, the quantum vacuum may not be at its lowest energy state and there are at least a couple of atoms per litre of space. Also, everywhere feels the pull of gravity. There is nowhere in the Universe you can go to escape any object’s gravitational pull. Actually, I question that, for this reason. Suppose you are orbiting a lorry floating in space in an otherwise entirely empty Universe a billion light years away. Someone sitting in the lorry reaches out, breaks off its driver’s side wing mirror and flings it into space. This will alter the number of objects in the Universe and the wing mirror will change the gravity acting upon you. How much difference would that make to your path? I suspect it will make so little that your accomplice may as well not have bothered, to the extent that it may actually be smaller than the grain of the Universe as expressed by Planck units, although I haven’t done the maths. If the Universe is big enough, there will definitely come a point where the influence a particular mass has on another will never add up to more than the Planck length, and this, to me, seems to mean zero influence. Then again, maybe this is the kind of quantum gravity thing which physicists have been slaving away for decades to solve and it’s more complicated than I think.
All of this notwithstanding, the Solar System is practically a point compared to the Universe, so the gravitational forces acting within it are considerable. There are of course nine major bodies the mass of Mercury or higher plus a further seven moons of planetary size, and various other smaller but still quite massive worlds such as Ceres and Vesta.
Each pair of these bodies has five points in space around it which, assuming they’re the only two bodies in the Universe, have balanced gravity. Objects placed at these points are stable. Either side, they will tend to fall towards these points. Something similar was mentioned by Jules Verne in his ‘Round The Moon’ («Autour de la Lune») whose astronauts’ weights drop to zero five-sixths of the way to their destination. Perhaps surprisingly, I haven’t read «De la Terre à la Lune», so for all I know it’s mentioned in there as well.
Given the eight planets and the Sun, there are of course five Lagrange points associated with each at any one time. This gives a total of forty. There are also five for every planet-moon pair, although not all are significant, so for example Jupiter and the Galileans have twenty as well as the five associated with Jupiter and the Sun. Some of these points are very close to each other and all are in constant motion relative to other frames of reference. There should also be similar balanced points between any two objects, such as, to be silly, Chiron and Hidalgo, or Ariel and Phobos.
All this means that in order to reach another world in the system, you don’t actually need to expend the energy necessary to get all the way from, for example, Earth to Mars because you’ll get help on the way. There will be a point following Earth in its orbit but further whither spacecraft might be aimed rather than Mars itself, and since there’s an increasing tendency for objects to fall towards these points, even the energy required to get there is less than it might be. Once in that location, it would be necessary to thrust a little further in order to approach the destination. The locations of the Lagrange points are along a line passing through the centre of gravity of the system and also forming the third point of an equilateral triangle with the two masses. Hence for the Sun and Earth, there’s a point between Earth and Venus, another between Earth and Mars, another where Antichthon would be, and one each 60° ahead and behind on our orbit. They would presumably also shift their positions slightly as Earth moves around its elliptical orbit. For immediate transport, the most useful locations for the Earth-Sun system are L1 and L2, which are both 1.5 million kilometres from Earth. Venus approaches Earth to about forty million kilometres, and of course it will have its own L2 point with the Sun at around a million kilometres closer. There will also be an equilibrium point about halfway between the two planets due to their masses being roughly equal, at twenty million kilometres, and the cis and trans lunar L1 and L2, 61 350 kilometres either side of Cynthia. Hence there’s a kind of “ladder” between Earth and Venus, with the lunar L1 and L2, the Earth-Sun L1, the midpoint between Earth and Venus and Venus’s L2. The respective distances are:
Earth to L1: 323 050 km.
L1 to Cynthia: 61 350 km.
Cynthia to L2: 61 350 km.
Translunar L2 to Earth-Sun L1: 1 054 250 km.
Earth-Sun L1 to Earth Venus equilibrium: approximately nineteen million km. This one will be slightly closer to Venus than Earth.
Venus equilibrium to Venus-Sun L2: approximately nineteen million km.
Venus-Sun L2 to Venus: approximately a million kilometres.
Hence there are seven rungs to this ladder, and yes there are issues with what happens when you get to Venus but I’ll go into those when this blog gets there! Each of these stages can be aimed at without using anywhere near as much fuel as would be required otherwise, partly because the spacecraft would be drawn towards them in any case. The difficult one is the equilibrium point, which is constantly circling the Sun and is influenced by its gravity too. A slingshot manoeuvre around Cynthia would accelerate the craft to some extent, but it’s hardly worth it as the escape velocity is lower than Earth’s so the speed would already have been moving that fast.
Mars is a more popular imaginary destination than Venus of course, and it too has a ladder of this kind. In its case, the Martian L1 is much closer to Mars but there are also the translunar and Earth-Sun L2s. The equilibrium point is also closer to Mars and since the gap between the orbits is larger, considerably further away. There would also be Lagrange points associated with the Martian moons but they wouldn’t be very useful as they’d be very close to the moons, but with the two moons rather than one, we start to get a hint of the complicated situation seen further out in the system. Venus has an almost perfectly circular orbit and Mars quite an elliptical one, to the extent that the seasons in the northern and southern hemispheres are very different and of different lengths, hence the larger southern ice cap. For the Lagrange points, this means they would move around quite a lot, and in doing so would move objects within them around too. All of these points would move by as much as 42 million kilometres over the 687-day Martian year, and that amounts to free travel, though only at 2600 kph, which isn’t significant over solar system scale distances although it is more than twice the speed of sound at sea level, and if you just care about getting there eventually rather than how long it takes you, it can help. This kind of “shuttle service” exists in equilibrium points between planets all over the Solar System, and technically there are eighty-seven of them overall, although not all are useful. They’re most concentrated in the inner system, where there are two dozen between the local planets and several more between them and the outer ones.
As well as all this, there are four planetary examples of L3 in the inner system, three of which move past Earth regularly and once again this is free travel, sometimes very fast. In Mercury’s case it can be almost 60 kps, and it would be possible to hop between them as well, carrying you closer to your destination with very little expenditure of energy. The question might arise in your mind of how this doesn’t violate the laws of thermodynamics, because it looks like a free lunch. The answer is that it isn’t because although there is a huge difference between the mass of a spacecraft and a planet, these activities do in fact ultimately add up to making minuscule differences to the planets’ orbits, but not significantly.
The equilateral points are often considered because they have features not often found elsewhere. There is a series of short stories called ‘Venus Equilateral’ written in the ’40s CE by George O. Smith about a radio relay station at the L4 point of the Venus-Sun system. Another well-known set of stories in this vein includes one by Asimov, all based on the same setting, where there are two stars of different spectral types (colours) occupying two points of the triangle and an Earth-like planet occupying the third. This gives it a day lasting two-thirds of its rotation period because it’s illuminated by both suns at a 60° angle to each other. In the real world, the most striking example of L4 and L5 are found in Jupiter’s orbit, where the Trojan asteroids are situated 60° ahead and behind Jupiter itself. This has led to the points themselves being referred to as “trojan”. For Jupiter there’s a “Greek” and a “Trojan” camp, although the actual names are mixed up between the two so that Greek characters from the Illiad are found in the Trojan camp and vice versa. The first of these to be discovered was Achilles, which is a dark red D-type asteroid, roughly spherical and around 133 kilometres in diameter. L4 is the leading point, and is referred to as the Greek camp because Achilles is there. There are more than six thousand asteroids here, the largest of which in either camp is Hektor, averaging at 225 kilometres across, which even has its own twelve kilometre wide moon called Skamandrios. Hektor is cylindrical and a lot longer than it is broad. The Trojan camp follows Jupiter at L5 and includes just over four thousand asteroids. Neptune also has Trojans, two of which are called Otrera and Clete. Twenty-two are known but of these only three are at the L5 location. They’re centaurs rather than asteroids, a category of object intermediate between asteroid and comet.
L5 was first introduced to me in 1976 when I heard about the Stanford Summer Torus Project (I may have got that name wrong). In the ’70s, a plan was devised to build a mile-wide wheel in space at the terrestrial-lunar L5 point which constituted a permanent space habitat. The July 1976 National Geographic includes a popularised version of the plan written by Asimov but the documents themselves made interesting reading. The general idea was to construct a six-spoked spinning wheel around 1 800 metres in diameter protected from radiation with a two metre layer of lunar regolith and have alternating agricultural and residential sectors with industrial processes and research carried out in the spokes, which constitute something like skyscrapers with lift shafts running along to the hub, which is a docking station and a low gravity environment. In the article this was envisaged as happening by 2026. Clearly it won’t be. Yet another space-related disappointment.
Another more serious omission is the possibility of building a solar power station at L5, which would solve all out energy and most of our climate problems at a stroke. I’ve mentioned orbital solar power elsewhere though, so I won’t be going into detail here. As it stands, these L4 and L5 locations are occupied by the Kordylewski Clouds, which are collections of dust. Their existence has been confirmed but there’s some confusion because when the Japanese lunar spacecraft Hiten flew through both as a form of gravitational assist, basically the same manoeuvre as I described for Venus, it didn’t detect an increase in dust concentration. However, it’s claimed that they can be visible to the naked eye, as they’re a dozen times the width of the Sun and slightly reddish compared to most other visible dust. There are a number of spacecraft situated at various Lagrange points.
The moons of Saturn, apparently unlike those of Jupiter, are sometimes in trojan relationships with each other. Tethys and Dione have a pair of them each: Telesto, Calypso, Helene and Polydeuces. However, Saturn is for another time on here, so for now I’ll leave it at that. However, the same kind of “rapid transit system” that I outlined in the inner Solar system would operate for the four complex satellite systems of the gas giants. Technically they would have a very large number of Lagrange points, but for most of the moons these would be unimportant because they are so small compared to their planets. For Jupiter’s four Galilean satellites, though, there are two dozen equilibrium points and twenty Lagrange points, and for Saturn’s seven roughly spherical moons, which excludes the rather large Hyperion, there would be over five thousand equilibrium points and thirty-five Lagrange points. This is more significant than it might appear, as by making the two regions around the planets more navigable, not only does it ease travel within those systems, but it also aids travel across them, particularly when one bears in mind that there will also be equilibrium points between the systems.
To conclude then, the Solar System is riven with locations which ease space travel, although sometimes they would mean that spacecraft traversing it would have to do so rather slowly. Another option is to hop onto an Earth grazer asteroid and hitch a lift to another part of the system, although again this could be rather slow. Some spacecraft have already taken advantage of the former approach, though not the latter, and it’s worth bearing in mind that when you look out into the system, there are many invisible but rather special points orbiting along with the visible planets and moons.
Alchemist Hennig Brand looks focused, if maybe a bit drained, in this 1795 painting by Joseph Wright. The painting depicts Brand’s discovery of the chemical element phosphorus.
I have repeatedly, perhaps incessantly, referred to the Fermi Paradox on here, but one thing I have never done is to do a survey of the most often given explanations, plus a few less common ones, so I’m going to do that here.
Before I start, it’s probably worth stating clearly what the paradox is. It goes like this. There are thousands of millions of stars in this galaxy, and innumerable galaxies in the Universe, and many of those stars are suitable for life-bearing planets, yet we never seem to detect or encounter any intelligent aliens. Why is this?
Before I get going, I want to mention the Drake Equation. This is a surprisingly simple equation thought up by the space scientist Frank Drake in 1961 CE. It’s simply a series of factors, all unknown at the time, multiplied together. It looks like this:
To explain the variables and the unknown constant N then, N is the number of civilisations with which communication might be possible in this galaxy. This figure is arrived at by multiplying the following factors:
R* is the rate of star formation in this galaxy.
fp is the fraction of those stars with planets.
ne is the average number of planets which can support life per planetary system.
fl is the fraction of planets on which life appears at some point.
fi is the fraction on which intelligent life develops.
fc is the fraction of intelligent life which develops technology making it detectable from elsewhere in the galaxy.
L is the length of time detectable signs are there.
There is said to be a problem with this equation first of all, which is that it’s susceptible to chaotic influence. The Club Of Rome released a report called ‘Limits To Growth’ in 1972 which predicted that various mineral resources would run out very quickly, but this didn’t come about because at the time it wasn’t appreciated that the results of a mathematical model often depend very sensitively on the exact values of the variables involved, now known as the Butterfly Effect. It’s been suggested that the same issue appies to the Drake Equation, in that most of the variables are not even approximately known, let alone exactly. And there’s another problem, which I’m going to illustrate with something personal. I used to have a list in my head of the ideal partner, and there weren’t many criteria on it. It amounted to similar values, personality traits of particular kinds and common interests. A short list. I stopped taking this approach eventually because I decided it wasn’t ideal for a number of reasons, but I also noticed something quite odd. There was one person who was absolutely ideal in these respects, and was also unavailable, so I began to look elsewhere, and was surprised to find that after many more years there wasn’t even one other person who satisfied those criteria even remotely. Don’t worry about me, by the way – I took a different approach and it worked out fine. The same phenomenon afflicted the a particular army when it attempted to produce a small range of uniforms somewhat suitable for everyone. Given criteria such as arm and leg length, chest and hip circumference and the like, all quite important for the clothes to fit, they found that nobody at all had the same such dimensions, and it was impossible. I’ve mentioned this before of course. Applied to this equation, it’s easily conceivable that working through all the variables, if they were known, could result in N equalling one, namely us humans here on Earth, and that’s it. Some of them are much better known now, or at least fp is: there are a very large number of stars with planets, probably most of them in fact, and the ones which don’t have them would be unsuitable for life anyway because they’re short-lived and life doesn’t have long to develop on them anyway. There also seem to be examples of planetary systems in which multiple worlds are suitable for life, such as TRAPPIST-1, with at least three planets orbiting within the habitable zone. The wording of the Drake Equation is also somewhat inappropriate, as it fails to take into account that moons might also be suitable for life. These increase the value of neconsiderably. fp is effectively close to one, and ne is quite possibly quite high. For instance, in this solar system it could be as high as 8 if moons are included. The presence of life on, or rather in, moons is, incidentally, one possible answer to the Fermi Paradox.
Using the information available at the time, Isaac Asimov worked his way through the equation in his 1979 book ‘Extraterrestrial Civilizations’ and concluded that there were 530 000 such civilisations in the Milky Way. His approach was quite exacting. For instance, he excluded the nine-tenths of stars which are in the galactic core and assumed that the total length of civilisations per planet averaged at ten million years, but was shared between different intelligent species evolving on the same planet. On the other hand, the book was written before it was realised that the Sun would make this planet uninhabitable æons before it would start to become a red giant. I think Asimov’s approach was a little tongue-in-cheek, but there is an issue about whether once intelligence evolves, it will ever disappear again on a planet until it becomes uninhabitable. We may also be in a position where once evolution enters a certain state, the appearance of the kind of intelligence which leads to technology may occur repeatedly. It’s been noted that there are a number of other primate species which now use stone tools, for example, and the nature of intelligence among crows, parrots, elephants and dolphins as well as primates is quite like ours. Given that Asimov’s estimate is exactly correct, which is unlikely, this makes it possible to estimate the average distance between such civilisations. The volume of the Milky Way Galaxy has been estimated at eight billion (long scale) cubic light years. The central nucleus, according to Asimov and others, is unsuitable for life, so assuming that to be spherical, which it isn’t of course, that gives the rest of the Galaxy a volume of around six billion long scale cubic light years. If there are 530 000 civilizations in that volume, that makes one per eleven million cubic light years, so that would make the average distance between them roughly 224 light years with spurious accuracy.
I’m actually going to do headings this time!
Absent Aliens
The most straightforward, and in a way even the most scientific and sceptical explanation, is that Earth is the only place in the Universe with life on it. There are various versions of this, but the simplest is just that life arose on this planet by sheer luck, and is practically impossible. Nowhere else in the Universe is there so much as a bacterium. Since we only seem to have one example of life known to human science, this is the only explanation which doesn’t rely on conjecture. At first sight, it might seem unlikely that there’s no life anywhere else although strictly speaking life would only need to be rare for this to be the explanation. There is in fact a peculiar issue with the origin of life on this planet. Although taking a few simple compounds as would’ve been found in the primitive atmosphere and oceans and exposing them to ultraviolet light and electricity does produce many of the more complex chemicals found in living things, there is an important set of compounds which are completely absent. DNA and RNA are very complex of course, but are made up of fairly simple building blocks of ringed nitrogen-containing compounds called purines and pyrimidines which comprise the rungs of the ladder and encode the genetic information. As far as I know, such compounds have never arisen in laboratory conditions. Clearly living systems can all synthesise them or they wouldn’t exist, but this happens through complex enzymes and already-organised biochemical pathways which rely on genes, made of those very same compounds. It’s a chicken and egg situation, and perhaps this means that the appearance of purines and pyrimidines is the single unlikely missing link on the way to life which has arisen just once in the entire history of the Universe, and therefore that the only place in the Universe where there is life is this planet. However, even if this is a one-off event, it doesn’t necessarily entail that life is found only here because it may still be that it arose somewhere in the Universe and spread widely. A few million years after the Big Bang, the whole Universe was much smaller, denser and warmer, to the extent that all of it was between the freezing and and boiling points of water and matter was dense enough to support life as we know it in space, and the elements from which it’s made were already available. Hence it’s possible that life has been around for almost as long as the Universe, and that it has a common origin, being able to spread as the Universe expanded.
There are even hints that life is present elsewhere in this Solar System. Some people, myself included, interpret the 1976 Viking missions’ ‘Labeled Release Experiment’ as positive in detecting life. This involved taking a sample of Martian soil (I always find it strange when extraterrestrial materials are described as soil. Martian soil is more like a mixture of rusty talcum powder and bleach), exposing it to a radioactively labelled soup of nutrients in water and measuring any carbon dioxide given off for radioactivity. It assumed that water would not be harmful to any organisms living in the soil. Anyway, the experiment was positive, but cast in doubt in view of the fact that the other two were negative. On Venus there have been three separate pieces of evidence for life in the upper atmosphere, not just the claim of phosphine. There is also something in some clouds which absorbs ultraviolet light and a compound called carbonyl sulphide is produced which is difficult to account for in the absence of life. On one of the several moons in the outer Solar System with subterranean water oceans, Saturn’s Enceladus also has geysers in which biochemical compounds have been detected. Other candidates include Titan, Europa, Ganymede and Callisto, and perhaps Jupiter. However, I don’t think this is good evidence for life elsewhere in the Universe. I think it could easily turn out that if there is life in these places, it has spread out from a common origin somewhere in this Solar System and without good data from elsewhere in the Galaxy we might still be alone apart from that.
One argument for life being common is that it began so very early on this planet, very soon after it first formed in fact, which makes it seem almost inevitable given the right conditions. Alternatively, it may have infected this planet from elsewhere, possibly Mars. However, this doesn’t follow because we only have one example of life known to us. There is also a very specific reason why life might be rare or non-existent elsewhere: phosphorus.
Back in the day, Isaac Asimov (yes, him again!) scared the living bejesus out of me in his article ‘Life’s Bottleneck’, highlighting a peculiar and largely ignored major environmental problem. There are all sorts of chemical elements needed for human life of course, but the major ones for all life make a short list: carbon, oxygen, hydrogen, nitrogen, sulphur and phosphorus. Phosphorus is far less abundant than the others and living things are distinctive in that they concentrate phosphorus way more strongly than the other elements compared to their surroundings, on the whole. The way industrial societies tend to deal with human excretion is often through sewers which expel the treated waste into the water and ultimately the sea. This waste is of course quite high in all sorts of elements, but is also sufficiently high in phosphorus that the alchemist Henning Brandt was able to discover it in the seventeenth century from performing transformations on human urine, as in the picture opening this post. The phosphorus which enters the sea only returns to the land very slowly because it’s mainly recycled by continental drift and gets washed off the land by rain anyway. Humankind began to notice in the early nineteenth century that the limiting factor in food production was phosphorus, and proceeded to mine phosphate rock for fertiliser, which has liberated a lot of phosphorus into the environment and leads to algal blooms and the like, which tends to poison the oceans and deprive aquatic environments of oxygen due to increased biochemical oxygen demand. It’s hard to know exactly what anyone can do about this which would make much difference, but a few steps which could be taken are to increase the amount of food from marine sources in one’s diet, which doesn’t mean fish, crustacea and the like because of their unsustainable “mining” but seaweed, and change the way one gets rid of urine, fæces being more a public health hazard which would probably be best dealt with by sanitation services, which does however need to happen, so that is a lobbying and pressure group-type issue. Anthropogenic climate change is of course vastly important, but it’s only one of various vastly important environmental issues, and the phosphorus one in particular is disturbingly ignored. Things are far from fine in that area.
Phosphorus limits biomasse. It’s the limiting factor in it to a greater extent than other elements because they are far more abundant. It might not be going too far to call the kind of life we are “carbon-phosphorus-based” rather than “carbon-based”, because the element has two completely separate but vital rôles in all life as we know it. One of these is that it stores energy and provides a chain for its release from glucose, even in anærobic respiration, in the form of adenosine triphosphate (ATP). This is how the Krebs cycle links with the rest of metabolism. Without ATP, there is simply no life. The other is that it forms the sides of the DNA and RNA molecules along with a sugar, in the form of phosphate. Again, without nucleic acids, there is no life, which harks back to the difficulty in finding a feasible process for purine and pyrimidine synthesis. The discovery that phosphorus was a major limiting factor in biomasse may not simply apply to life on this planet, but throughout the Universe.
Why is this an issue? Wouldn’t we find that other planets in the Universe have about the same amount of phosphorus as there is on Earth or in this Solar System? Well, no, or rather, quite possibly not. Odd-numbered elements are usually rarer than their even numbered neighbours in the periodic table, and phosphorus is element number fifteen. Of the other elements playing a major rôle in life here on Earth, only nitrogen and hydrogen have odd numbers. Hydrogen is a special case because it’s the “default” element. In parallel universes whose strong force is slightly weaker, the only element is hydrogen. Its abundance there is one hundred percent, and most atomic matter in the Universe is in fact hydrogen, because the rule doesn’t apply to it. It’s a given. Nitrogen is still the seventh most abundant element because it’s fairly light and therefore likely to form. Phosphorus is the seventeenth most common everywhere on average, and is only formed when silicon atoms capture neutrons and decay. Only 1‰ of Earth’s crust is phosphorus and 0.007‰ of the matter in this Solar System. Its main mode of formation is in Type II supernovæ.
Supernova 1987A, a Type II supernova in the Large Magellanic Cloud
Type II supernovæ result from the collapse of stars whose mass is between eight and four dozen times the Sun’s. They only “burn” silicon for a very short period of time, during which a few silicon atoms will become phosphorus. Then they explode, scattering their elements across their region of the Galaxy in a shockwave. As time goes by, these supernovæ slowly increase the abundance of various elements, including phosphorus, but the regions of the Galaxy where the element is relatively abundant may be quite small and scattered, at least for now. This means that effectively the Universe, and on a smaller scale our galaxy, may be a phosphorus desert with a few small oases where it is even remotely “abundant”. Asimov said of phosphorus that we can get along without wood by using plastic, without fossil fuels by using nuclear power and without meat by substituting yeast, but because phosphorus is such a fundamental part of our metabolism there is no such substitute.
Now the question might arise of why so much importance is placed on phosphorus here when life seems to be so very adaptable and able to find ways round problems, and this is indeed so, but there are reasons for believing that this cannot happen with this element. It’s locally more abundant in geothermal vents and carbonate-rich lakes, which have fifty thousand times as much oxygen as seawater has, and it can also become concentrated in rockpools due to capturing the runoff from water and concentrating it when it evaporates at low tide, so there are various high-phosphorus places on this planet where life could have begun, which may well not be elsewhere in the Galaxy. Now suppose there are various different processes which could lead to life beginning here which do not involve phosphorus, which seems feasible and in fact it’s considered slightly odd that all life known here seems to have a common origin. The one which needs phosphorus is at a disadvantage compared to the ones which don’t, because it relies on a scarce element and wouldn’t be able to spread so easily to environments where other life for which it was not a limiting factor would be able to thrive. Therefore it very much looks that the kind of life which exists on this planet has the only kind of biochemistry possible here.
This could have major consequences for our own space travel. It might mean, for example, that we can’t settle on planets in distant star systems and thrive without bringing our own massive supply of phosphorus, and this also makes it more difficult for other intelligent carbon-based life forms to colonise the Galaxy, because not only are there vast distances between the stars, as we already know all too well, but even those distances are small compared to the small spheres of phosphorus-rich systems scattered sparsely through the Milky Way. They could be thousands of light years apart. Moreover, although the Universe is very old, it may have taken this long to accumulate enough of the stuff for life to be possible at all, meaning that the idea of elder civilisations out there which appeared æons ago may be completely wrong. This leads to a second variant on the idea that life is rare.
We’re The First
It may be that we don’t know of any aliens because there aren’t any, but there will be one day, either because of us or because they will evolve later. The phosphorus bottleneck is one explanation for this, but it could also be that we got very lucky with evolution. Over most of the time this planet has existed, it’s had life all right, but it was single-celled and those cells weren’t even the more complex ones like amœbæ, and life chugged along just fine, though it didnæ end up producing anything very impressive-looking or even visible to the naked eye. It could very well, for all we know, have continued in that vein until the Sun roasted it out of existence, but it didn’t. In fact this is another explanation entirely which is worth exploring as such: simple life is common, complex life rare.
One way to look at evolution as it’s happened here is as a series of improbable events. Some even say that the advent of oxidative phosphorylation is improbable, and that even anærobic respiration was an improbable step, which would limit life so severely as to effectively rule it out in any meaningful sense. Beyond this, the evolution of cells with separate nuclei containing DNA surrounded by an envelope of cytoplasm with symbiotic bacteria living within it also seems quite unlikely, and we haven’t even got to the simplest animals and plants yet. Maybe on other planets these improbable events have taken longer than they have here, or don’t happen at all, and although there will be intelligent life there one day, that point is hundreds of æons in the future. There are a couple of unexpected things about the Sun. One is that it’s a yellow dwarf rather than a red dwarf, and since those are both apparently suitable for life-bearing planets and liable to last many times longer than the Sun, a random selection of intelligent life in the Universe might be expected to result in finding an organism living on a planet circling a red dwarf 200 000 000 000 years in the future. The other weird thing about the Sun is related to this. If there is something ruling out life on red dwarf planets, such as frequent flares, it’s still more likely that intelligent life would evolve on a planet slightly cooler than the Sun, that is an orange dwarf such as α Centauri B or either of the 61 Cygni binary system, because the star would both last longer as such and have a habitable zone which lasted longer in the same place. Perhaps the reason the Sun is a yellow dwarf is that we are ourselves unusual and have evolved unusually early, so the absence of aliens is in a way connected to the unusualness and apparent unsuitability of this star.
The ‘Red Dwarf’ universe has the second version of absent aliens which in fact amounts to “we’re the first”. There are other intelligences in ‘Red Dwarf’ but they’re all derived from Earth in one way or another, and this is “word of God” because Rob Grant and Doug Naylor have said so themselves. In this version of us being first, we are indeed the first but will go on to seed the Universe with our machines and organisms until it teems with intelligent life. We just happen to be living before that’s happened. I would argue against this for the same reasons as I did here: if that’s the case, aren’t we just incredibly unlucky to have been born before it happened? My answer to this is that it will never happen, but there’s a further probabilistic difficulty in the fact of our existence here and now on this planet 13.8 æons after the Big Bang: the scepticism about our future is about time, but could equally well be applied to space. If I am a random intelligent entity in the Universe and it’s normal for intelligent life forms to expand out and settle the Universe in untold high population numbers, why am I not one of their much greater number? Here’s a possible answer:
Intelligent Life Destroys Itself
This was a popular idea from 2016, when Donald Trump got elected, but has been stated many times, in connection with climate change, the Cold War and hostile nanotech. Maybe there’s something about monkeying around with the world which ends up killing species off. This could be quite low-key. For instance, it’s possible that if we had continued with a mediæval level of technology and population and it had spread around the world, although climate change might not be as severe as a result of our own activities, we might still reduce the fertility of the soil and have plagues and famines wipe us all out in the long run. However, once an industrial revolution has occurred, bigger problems start to emerge, the most prominent and obvious being anthropogenic climate change in our case, but another issue is the use of weapons of mass destruction, or AI, complexity or nanotechnology causing our extinction. The Carrington Event is a famous solar flare in the mid-nineteenth century which led to electrocutions from the only electrical telecoms which existed at the time, telegraphy. If this happened now, and it is likely to recur quite soon statistically, the internet and devices connected to it could be physically destroyed, and we are now very dependent on it. Nanotechnology is another potential threat, with the “grey goo scenario”, where tiny machines reproduce themselves and end up eating up the entire planet. This has been explored and seems to be impossible, because limiting factors like phosphorus for life also exist for such machines in the form of other elements, but one thing which could happen with nanotech which is much cruder is that it simply becomes a ubiquitous particulate hazard for everyone. Complexity probably amounts to unforeseeable apocalyptic scenarios. For instance, climate change could lead to wars over water which would restrict access to metals needed to maintain a physical infrastructure we need to provide food. In a way, as an explanation of the Fermi Paradox the absence of aliens might constitute an important lesson for us, but the details are less important than the consequences, which are that there are no spacefaring or communicating aliens because they always die out soon after becoming capable to doing anything like that.
I actually do think this explanation has some factual basis, although it isn’t quite as drastic as it seems. I think there is a brutal pruning process in technological and social progress which prevents harmful aliens from leaving their star systems, and unfortunately in that process there are myriads of innocent deaths and enormous sufferings, holocausts and the like. The way I think it works is that tool-using species may either smoothly develop in a consistently altruistic way or in a more internally aggressive manner which may or may not be resolved by the time they attain the ability to travel through space. We are now at such a crucial stage, and we may destroy ourselves, solve our social problems and opt not to go into space or solve our social problems and expand into space. There may be a law of nature which means an overtly belligerent attitude is self-defeating and such species, although they may not be essentially aggressive, always destroy themselves rather than travel to other star systems. In other words, I believe in this explanation, but it may not be an explanation of the Fermi Paradox. I think it means that any aliens we encounter who have left their own star systems will automatically be peaceful and coöperative. If this is too tall an order then nope, there are no interstellar civilisations, although there may be aliens who haven’t wiped themselves out yet, and even aliens who occupy an entire star system. This is the opposite answer to the Fermi Paradox to the next, fairly recently devised, one:
The Dark Forest
This is named after the work in which it was apparently first suggested, 黑暗森林, by the Chinese SF writer 刘慈欣, Liu Cixin, in the ‘noughties, although it’s hinted at in the preceding novel, 三体, whose English title is ‘The Three-Body Problem’. Avoiding spoilers, the basic idea is that we never hear from aliens not because there are none, but because they’re hiding from each other. I’ve mentioned this before but it bears repeating here. Aliens are assumed to see each other universally as potential threats and will therefore act to destroy each other whenever they become aware of their existence. In response to this, they all hide themselves and the reason we detect no signals from them is that they assiduously avoid making themselves detectable. Against this dark background, humans are recklessly advertising our presence to all and sundry, positively inviting ETs to come along and destroy us, even if only to avoid attention being unwantedly attracted to themselves by even more powerful minds which would swat them like flies.
It can be argued that this situation reflects the real situation we observe in ecology, where camouflage and mimicry protect organisms from each other and disguises of various kinds are adopted to prevent themselves from being sensed, killed and eaten. I think 刘慈欣 has a rational approach to the issue, and in fact quite a positive message as he believes that we’ve got the idea of humans and aliens the wrong way round. He believes that there is a prevailing view that aliens will be friendly while we are aware of the hostility prevailing between powers in the human world, but that the real situation is that human beings are potentially much more altruistic than we give ourselves credit for, and it’s likely to be the aliens who behave in a vicious manner towards us. Other believers in the Dark Forest answer say that non-believers in it are being anthropomorphic by imagining that aliens would not be hostile, because the biosphere we know of is quite savage. I’d say that this is a projection, and also that to extend the comparison, there are circumstances where organisms positively advertise their presence, for example to seek a mate or as warning colouration. The former is a little hard to fit into this scenario, but the closest analogy would probably be something like exchange of information for the benefit of both cultures, a relationship described ecologically as symbiosis. For instance, assuming the presence of multiple hostile civilisations in the Galaxy, it would seem to make sense for two less powerful cultures to tell each other about the threats. Something like warning colouration is another possibility. A species of aliens might wish to broadcast its potential hazardousness to others in order that it not be bothered, rather like the Mutually Assured Destruction (MAD) scenario, and in fact the Dark Forest is based on game theory, which is influenced by MAD.
The idea of more powerful civilisations disrupting and destroying less powerful ones has a persuasive-seeming precedent in human history, because in general European and European-derived cultures have tended to do that to a horrifying degree on our own planet to other human cultures. This,though, is based on what happens within our own species in highly specific circumstances which rely substantially on the idea of territory and land use, along with a religious and political outlook used to justify those atrocities. It’s this which seems anthropomorphic to me. The Dark Forest seems to be the same situation translated into interstellar space and assumes that the species or entities involved are similar to us in the mode we have employed during history, which is likely to be highly atypical even for us, and we may also be projecting our own assumptions onto ecology when we assert these things. There are plenty of examples of peaceful coöperation between species, such as symbiosis and the very fact that multicellular organisms are themselves alliances of unicellular ones for mutual benefit in the same way as an ant colony is. There’s also the consideration that life on this planet has been around for a very long time now and it would seem to make more sense to nip things in the bud before intelligence of our kind has even evolved, but this hasn’t happened. However, I do maintain a modicum of sympathy and interest in 刘慈欣的 argument because I suspect it’s linked to dialectical materialism, and in order to assess it properly I would have to know more about Maoism, the current status of the Chinese 共产主义, his status with respect to the Chinese government and so forth. I would maintain that China, because it has a stock market, is capitlist, but that doesn’t mean it doesn’t have valid philosophical views built upon its ideology. It’s all a bit complicated, and interestingly something he goes into himself in his novels. Although I don’t agree with the Dark Forest at all, laying it out as a Marxist-influenced argument is interesting and may suggest other solutions to the Fermi Paradox which are freer from the taint of capitalism.
Spending Too Much Time On The Internet
I have felt since the early 1980s that there may be a trade-off between Information Technology and human space exploration. I don’t want to go into too much depth here but I suspect there is an inverse relationship between the two, such that the more IT advances, the less effort is expended on sending people into space and the more human beings explore the Universe, the less happens in the sphere of computing and the like. This is a subject for at least an entire post, and I won’t do more than mention it in passing here. Suffice it to say that when the Drake Equation and Fermi Paradox were first thought of, IT was very primitive compared to how it is now, although the internet itself is quite possibly the most predictable thing which has ever happened (see for example Asimov’s ‘Anniversary’ published in 1959 or Old Burkster’s Almanac in the 1970 ‘Tomorrow’s World’ book, which actually predicted the exact year it would take off (1996), so the link could’ve been made then. In fact, Olaf Stapledon predicted something similar in ‘Star Maker’ in 1937, where he imagined a species of aliens which ended up never leaving their home planet, which is doomed due to losing its atmosphere, because they end up lying in bed all day hooked up to a global information communications system, which also tellingly begins by encouraging cosmopolitanism but soon degenerates into echo chambers.
The “spending too much time on the internet” solution to the Fermi Paradox goes like this. We went through the Space Age and appear to have come out the other side. On this other side, we have an almost universally accessible network of devices for information and communication. If we are able to develop sufficiently convincing virtual worlds, we might all end up in the Matrix and not bother going into space at all. Perhaps this is what always happens to sufficiently advanced technological civilisations. The author of the Dilbert cartoons, Scott Adams, once stated that if anyone ever managed to invent the Holodeck, it would end up being the last thing ever invented because everyone would just end up living in that virtual world and not bothering with anything else. This is different to the idea of the Universe being a simulation because in this situation everyone knows where they are is not “real”, although Gen-Z-ers might argue with a definition of reality which divides meatspace from cyberspace with considerable justification, and willingly participates anyway. If you’re doing that, why bother to explore strange new worlds or seek out new life and civilizations. In fact you could do that anyway because I’m sure a virtual Enterprise would be one of the first things to be created in this virtual world, if it hasn’t been already. It wouldn’t be “real” in the way we understand it, but who are we to say? It would, however, mean we aren’t going to meet any aliens because they’re all on Facebook or something, which we may already have noticed is so.
One problem with this answer is that it assumes aliens are all similar enough that they get to a stage when they not only start to create communal online environments but also then get addicted to them and abandon space exploration. It isn’t clear that they’re similar enough even to have the same mathematics as we have, so why assume this is what happens? It may well happen to humans, but that could have little bearing on what happens anywhere else.
This can be turned round:
The Planetarium Hypothesis
There are several different versions of this and it blends into another version. The most extreme and probably easiest to state version is that we are living in a simulation, which Elon Musk claims playfully and perhaps not very seriously to believe. The argument that this is so in his case is based on the expectation that technological intelligences would very commonly get to the point where they could simulate the Universe, and within those simulations, more technological intelligences would do the same and so on, meaning that the number of virtual worlds compared to the real one is very large and therefore that we are much more likely to be living in one of those than the unadulterated physical Universe. Hence this is not the real world, and for simplicity’s sake, or perhaps as an experiment, we’re sitting in a simulation which, unlike base reality, is devoid of aliens. The alternative, according to Musk, is that in the near future we’re likely to become extinct, because there would then be no intelligent civilisations capable of simulating the Universe and therefore that we are living in base reality, but not for very long because there is about to be a massive calamity which will wipe us all out. I don’t find this argument to be at all satisfactory. Like the previous argument, it assumes that history will proceed in the same manner for everyone and that we all end up producing simulations. It also assumes simulations are possible when there are at least two good reasons for supposing they aren’t. One of these is the three-body problem. Three bodies whose attraction to each other is significant will behave chaotically in almost all cases and there are no ways of predicting their movement with a finite number of mathematical operations. There are exceptions to this. A few entirely predictable stable situations exist, most of which are too rare to occur in the observable Universe although there is one which may well exist somewhere in a star system in a galaxy far away. However, that’s the three-body problem. The Universe we experience has many more bodies than that in it. The number octillion has been mentioned in connection with this. For the Universe as we know it to be simulated, even the bits we’ve visited with space probes, an infinitely complex computer would be needed. Another problem is that of consciousness. Simulating consciousness doesn’t seem to be the same thing as actually being conscious, yet we know ourselves to be conscious. We could be mistaken about our substrate – maybe it’s transistors or qubits rather than brain cells – but for that to be so, panpsychism also has to be true, which as far as I’m concerned is fine but most people don’t accept that view of the nature of consciousness. There may be a functionalist solution though. A further objection is based on Musk’s own thought about the multiplicity of simulations. If a powerful computer can run a simulation of the Universe in which other computers can also run simulations of the Universe and so on, the largest number of simulations running would also be the most rubbish ones, at the bottom of the pile, because that’s the point at which the “tree” has its final twigs, and that means we’re more likely to be in a rubbish simulation, but we aren’t, and that simulation would also be too simple to allow any further simulations to be run. Minecraft exists, therefore we are not living in a simulation!
One point in favour of the Planetarium Hypothesis is that it’s highly sceptical and makes very few assumptions compared to some other solutions, and in that respect it’s similar to Absent Aliens. There are also less extreme versions of this which take the word “planetarium” almost literally. We have never bodily travelled more than 234 kilometres into trans lunar space, which happened with the ill-fated command module of the Apollo XIII mission in 1970. Therefore, for all we know the rest of the Universe could be faked for our benefit, although this assumes that the likes of the Pioneer and Voyager probes are just sitting somewhere being fed loads of false data or something. There’s a decision to be made in this explanation as to where one cuts things off and decides everything else is fabricated, and it begins inside one’s own head. This thought has been used at least twice by major SF writers. In the 1950s, Asimov (again!) wrote a story where the first astronauts to go behind Cynthia (“the Moon”) found it was painted on a board and propped up by wooden struts. Later on, Larry Niven, who had written himself into a bit of a corner with his Known Space series because he had to try to maintain continuity, playfully came up with the idea that none of it had happened and it was just being simulated in VR on Cynthia.
It’s been suggested that the almost perfect match between the apparent size of Cynthia and that of the Sun is a kind of Easter Egg, that is, a clue that we’re living in a simulation. It doesn’t seem necessary for the existence of intelligent life here that that match should be so perfect, and there seems to be no explanation for it other than chance. And it is peculiar. It will only hold true for the approximate period during which oxygen-breathing terrestrial animals can thrive here because the distance between Cynthia and Earth is increasing by a few centimetres every year. It would be interesting to run the figures about this, to see for example how big and/or distant a moon would have to be if we were orbiting within the habitable zone of 61 Cygni B or something, because there might be a clue there.
I have to admit it’s tempting to believe that the empyrean, as it were, is hidden from us by some kind of holographic Dyson sphere, i.e. that the planetary Solar System and Kuiper Belt are surrounded by a fake display of the rest of the Universe, just because it’s an appealing idea, and there are even reasons for supposing this to be the case. However, that would mean that Pioneers 10 and 11 along with Voyagers 1 and 2 either hadn’t hit the solid sphere of the sky, as it were, yet, or that they had but are themselves in a simulation of interstellar space. It was recently suggested that the Solar System may be enclosed in a vast magnetic tunnel as it moves around the Galaxy, but it seems to be several hundred light years wide and a thousand light years long, so if that’s the edge of the simulation it seems a bit pointless. Another appealing idea associated with this is that all that stuff about Venus being a hot, steamy jungle planet and Mars having canals and Martians living on it could be entirely true and we’re just having all that concealed from us and, again, fake data being fed to space probes. Of course, if human astronauts actually did go out there this would be harder to maintain, unless one begins to suppose that they’re all abducted and brainwashed or something.
The answer this kind of blends into is the
Zoo Hypothesis
This used to be my favourite answer when I was younger, and I just basically assumed it was true, but it lacks the parsimony of absent aliens or the Planetarium Hypothesis. If you’re familiar with ‘Star Trek’, you’re probably aware of the Prime Directive, also known as Starfleet General Order 1:
“No starship may interfere with the normal development of any alien life or society.“
We don’t know how extensive or organised any technologically advanced species or other intelligence which might exist outside our Solar System is, or anything about their ethics or politics. However, the admittedly anthropomorphic analogy with how things are here with uncontacted people on our planet, we do have at least a rudimentary ethic to protect them. We note that they are self-sufficient, unfamiliar with how things work in global society, highly vulnerable and at risk of extinction. Often the reason their lives do end up disrupted is due to governments or multinationals wanting to get hold of resources which happen to be located where they are. This is never going to be the case for Earth in terms of mineral resources, as even phosphorus is found elsewhere in sufficient quantities, if that turns out to be important, and there isn’t going to be any kind of invasion to get hold of metals or whatever from here. What we may have is culture and biodiversity. Speaking of biodiversity, there are reserves and national parks in many countries on this planet, so maybe we’re in one of those. It isn’t clear whether to an alien we would be more like an uncontacted indigenous culture or endangered wildlife, depending on how different our intelligence and minds are, but there are measures in place here for the protection of both. Moreover, when the difference is large enough, it’s possible for human technology to maintain an environment in captivity which may create a persistent illusion of the habitat an animal is found in before human interference, and we could be in such an environment.
I’m going to present my train of thought, as was, on this issue, starting with the premises of the Fermi Paradox. The Galaxy is more than twice as old as this Solar System, so it’s fair to assume that intelligent life evolved many æons ago, even before the Sun formed. This is also more than ample time for the Milky Way to become thoroughly known to the technological cultures that exist within it, and it can also be assumed that any species able to leave its star system must have achieved some kind of utopia in order to be able to use the energy and resources efficiently enough to do so. Therefore the probable situation across the Galaxy is that a peaceful and benign community exists which will protect the less advanced civilisations found within it. This applies to Earth. We are observed by aliens and there is a non-interference ethic which prevents us from being contacted because of the disruption that has been seen or modelled to occur in the past if it happens too early in the history of a species. This policy has been in place for thousands of millions of years. When we reach a certain stage in technological and perhaps social development (I actually think these always occur hand in hand), we will be contacted and, perhaps after a probationary period, invited to join the “Galactic Club”. There is well-worn standard procedure for doing this. It can also be supposed that because this society is so ancient and long-established that it works as perfectly as any society could, so the procedures can no longer be improved upon. I should probably also mention that back then, as now, I thought in terms of technological cultures rather than species. Individual races come and go in this scenario just like individual humans in society, but the culture is permanent, or at least very durable. This is the condition of the Galaxy.
Although my use of the word “culture” calls Iain M Banks’s fiction to mind, I began to use it before they were first published. The word is just very apt to describe this kind of situation. I used to be very confident that this was how things were, and it is more or less the Zoo Hypothesis. Where it falls down, I think, is in having a quasi-religious tone to it. It could be argued that this is akin to our own ancient tendency to project our wishes and stories onto the sky, and I do think this is significant. However, there are different ways to respond to that thought. One is that we unconsciously know how things are and therefore made various attempts to express that fact given the current state of knowledge throughout our history. Alternatively, the reverse could be true: we have a tendency towards magical thinking which results in religion, and this leads us towards imagining how to have things this way in the face of what we perceive to be powerful evidence against the supernatural. Some fundamentalist Christians accept the existence of aliens but see them as demonic. It’s very difficult to examine oneself closely and neutrally enough to come to a firm conclusion as to what belief in the Zoo Hypothesis is motivated by, and therefore to assess it scientifically or rationally. There are certainly inductive inferences operating within the argument, but perhaps not deductive ones. “Accusing” it of having a religion-like flavour is not the same as refuting it, and part of the decision as to whether to accept or reject it relates to how one feels generally about religion.
That said, there are some ways of arguing rationally against it. It only takes one small group within the Galaxy, perhaps the closer star systems in this case, to behave differently for First Contact to occur. Since I’ve concluded also that mature interstellar cultures must be anarchist, there would be no law enforcers to prevent this from happening. However, anarchist societies are not necessarily chaotic and may have customs which prevent such things from happening. For instance, queues are not generally legally enforceable but people rarely jump them due to social disapproval or the simple act of people providing the service one is queueing for ignoring violators, and there are apparently places where there are no laws regarding traffic priority at junctions, but people behave harmoniously according to custom. It hasn’t escaped my attention that I’m talking about Douglas Adams’s “teasers” here. As far as we can tell, though, this hasn’t happened. Or has it?
UFOs Are Alien Spacecraft
Like most people, I reject this out of hand but there’s a point to stating in detail examples of what people who believe this generally think. There is some variation in the details, but I think it works roughly as follows.
For quite some time now, perhaps since prehistory, this planet has been regularly visited by spacecraft ultimately originating outside this Solar System, containing intelligent aliens. These aliens sometimes abduct humans and other animals to do experiments on them. The governments of the world are aware of the situation but keep it secret from the public to avoid panic or because they’ve made some kind of deal with the aliens.
This view has a number of variants and is the basis of several religions. One such view is that ancient astronauts are responsible for world religions and have interfered in our history, perhaps even interbreeding with our ancestors or genetically engineering them for the appropriate kind of intelligence. Incidentally, this is known as “uplift”. Another view, of course, is that the human world is run by alien reptilian humanoids or shapeshifters for their own nefarious purposes and not for human benefit. There are also notions such as aliens wanting to get elements or substances from this planet which are rare elsewhere in the Universe, such as human enzymes or for some reason gold.
I stopped believing that UFOs were alien spacecraft when I was about ten, I think. There are a number of very good reasons to suppose this is not the case. The initial trigger that ended my belief was that the occupants of the craft were said to be humanoid in possibly all cases, which I saw as completely incompatible with them being aliens. For a while, I believed they were time machines and the beings on board were highly evolved humans from the future. Although I no longer believe this either, I still think it’s more plausible than the alien idea. I had a bit of a blip in my disbelief when I heard about the star chart aboard the spacecraft in the Hills’ abduction, which closely maps nearby star systems from a certain angle, but now think that this could be made to conform to the pattern drawn by projecting the stars in various different ways until a rough fit was achieved, which is in fact what happened with this.
There are various problems with the flying saucer hypothesis. One is the fact that people report humanoid occupants, although there are possible explanations for this. The entities could be manufactured or genetically engineered to look like us or convergent evolution might ensure that tool-using species are humanoid. Another is more serious: UFOs are visible. People report detecting them in various ways, such as on RADAR screens or more often visually. Even with our own relatively limited technology, we are able to make things almost invisible and undetectable on RADAR, but we are expected to believe that aliens can’t do this even though they can cross interstellar distances with ease. The alternative is that they want to be seen, but this is an unsustainable intermediate position because it doesn’t make sense for just a few craft to be seen occasionally. It can be confidently asserted that if they wanted to be invisible, they would be, so it then becomes necessary to explain why they don’t want to be. It’s fine as such if they don’t, but it would also mean the idea that they only associate with the “leaders” of the human race goes by the by. Also, the very idea that they would respect governmental power structures makes no sense. There’s no reason to suppose aliens would have government or that they would pay more attention to the people who happen to think they’re at the top of the pyramid. Of course, I’m personally convinced that they’re all anarchist, but there are other circumstances in which aliens might wish to subvert the hierarchy or just end up doing it anyway. Apart from anything else, they are after all aliens. They may not have the capacity to understand the nuances of human governmental systems, or they may arrive here not having learnt how it works. Or, they may wish to disrupt human society for nefarious purposes by inducing the panic world governments are supposèdly trying to avoid by keeping them secret. The nub is that if aliens were visiting us, they’d be able to hide from everyone, and if they didn’t hide from everyone they’d hide from no-one.
I do believe in UFOs of course. There very clearly are aerial objects which remain unidentified by any human observer. These are often things like Venus, birds, drones, weather balloons and so on, but I do also think there is another, very small set of other objects. These are secret military aircraft which happen to get spotted by people from time to time but whose existence isn’t openly admitted by the authorities. The one time I saw a UFO I couldn’t explain, that’s what it turned out to be, so maybe I’m biassed because of that.
I also believe that aliens would be benevolent for the reasons I set out under the Zoo Hypothesis.
Simply not believing that UFOs are alien spacecraft is not the same as believing we aren’t being visited or observed though. Maybe they are here. Maybe we are the aliens without knowing. I’m getting ahead of myself though. Here’s another similar idea to UFOs being alien spacecraft:
They’re Here But We Haven’t Noticed
This one is something of a mental health hazard because it very much stimulates paranoia, and again there are several versions of this. The closest one to the previous explanation is that there are indeed alien spacecraft, or perhaps nanoprobes, visiting or monitoring this planet but we can’t detect them, or haven’t done so. It does make sense that if they wanted to remain hidden, they would succeed in doing so, given their level of technology. One suggested means of eploring the Galaxy is to launch swarms of minute spacecraft in order to save energy and avoid collision with dust and other bodies between the stars simply by being smaller. It would also be relatively easy to secrete a reasonably large completely visible probe somewhere in the Solar System or in orbit around Earth without attracting much attention. Another somewhat disturbing further option exists. Right now, we can do 3-D printing and have some ability at genetic engineering. We aren’t that far off inventing a replicator, should that prove possible at all, bearing in mind that things often seem easier before they’ve been done. But for a technology far in advance of our own, it should be possible not only to produce a completely convincing living human, but even one whose memories are false and doesn’t even realise they’re the product of an alien machine. In other words, we could ourselves be aliens without even knowing. This kind of prospect is very similar to the kind of beliefs many children have and also has some resemblance to Capgras Syndrome. Whereas all of these things are possible, they are almost by definition non-scientific as they have no way of being falsified. Perfect camouflage is just that. No test can be performed to verify or refute that it happens. Therefore, whereas all of these things seem entirely feasible, they aren’t actually particularly meaningful as a simpler explanation for what we observe is that there are no alien spacecraft or “pod people”.
They’re Too Alien
Many answers to the Fermi Paradox seem quite anthropomorphic in one way or another. For instance, both the Zoo Hypothesis and the Dark Forest attribute perceived human-like behaviour, in opposite directions, to these unknown and possibly non-existent beings. But what if the reality is that aliens are in some way intelligent but also truly alien? What if they’re just fields of singing potatoes? They’re very intelligent, to be sure, but all of that cleverness is channelled into art so sophisticated and arcane that it can’t be grasped by humans, and also they sit there and do nothing else. They might send up a shoot or two with eyes on the end every now and again and look at the stars and planets in their night skies, but it doesn’t grab their interest. Of course, the singing spud scenario is borrowed from Grant and Naylor, but it’s one of many possibilities, some unimaginable and all unanticipated. We are one example of a tool-using species. Another one may be dolphins, and it doesn’t look like they’re going to develop our kind of technology at any point, not only because they live in the sea and don’t have anything like hands, but also because they’re just not interested, and that’s just on this planet and quite closely related to us. Or they could be a spacefaring species like some humans aspire to be but just have no concern about meeting any aliens or getting in touch with them. We might not even recognise each other as alive. For instance, what if they were a rarefied plasma drifting between the stars?
Different Or No Maths
I went into this one the other day here. Most of us humans don’t distinguish between subitising, which is the ability to judge how many items there are at a glance and which we are usually able to do about five, and the kind of activity which counts as arithmetic and mathematics. I won’t wade in here but there doesn’t seem to be any good reason why we would have evolved an aptitude to do mathematics given our lifestyle, or for that matter for any other species to do so given its niche, but we’ve done so anyway and this has somehow proven to be useful in rocket science and the like. Maybe it’s this which is missing from other intelligent life forms’ faculties, so they do fine building some kind of civilisation where everyone isn’t just a number, but they never leave their home world because they never develop anything able to do that.
Right, so this has turned out really long, so at this point I’m going to stop and publish. Part II in a bit, possibly tomorrow.
Right now, the chances are that everyone reading this is a basic human like me, living on Earth, or at an outside chance, in low Earth orbit (who am I kidding‽). Consider that condition. What are the chances that that’s what you are if human life goes on and our descendants fan out into the Galaxy? I’ve gone into this many times of course, and the Doomsday Argument, as this is called, is flawed, but it’s worth going into it again for the purposes of applying it to the situation in which the human race finds itself today.
I’ll just recap briefly. There was a guy who visited the Berlin Wall in the 1960s and predicted that it would come down at approximately the time it did through estimating the probability of where he was in the total number of visitors to the Wall, using only probability, statistics and the time since it had been put up. His name was Brandon Carter, and he later applied a similar argument to estimating how long the human race has left based on the assumption that one is about half way through the total number of human births. When I did this calculation based on my own date of birth, the 1977 CE estimate that 75 thousand million people had been born before me, which covered the past six hundred millennia and a doubling period somewhere around three decades, as it was at the time, it gave me the result that the last human birth would take place around 2130. There are various silly aspects to this argument. For instance, if Adam existed and had made this calculation just before Eve appeared, he would conclude that the human race would be most likely to end with Eve’s death. By the way, I am not fundamentalist and therefore do not believe Eve and Adam ever existed. I just want to make that clear.
Although this is not a particularly marvellous argument, I do think a similar one works fairly well in one particular area, as I’ve mentioned before. It does in fact seem fair to assume the principle of mediocrity about one’s own existence. In that respect, it’s fair to assume I’m a typical example of a human and have been born at a time when prevailing conditions are “normal”, i.e. that the fact that I find myself living at a time when we have only ever lived on one planet and are not cyborgs to a greater extent than Donna Haraway claims. Transhumanism is not the usual human condition and there are neither orbiting space colonies nor settlements on other worlds. If we even settled ten other worlds they would only need a population over the whole period humans dwelt on them about equivalent to the current population of this planet for us to be outnumbered, and that’s a very modest estimate of how human history would unfold if we began to live elsewhere than on this planet. It would be more likely for there to be numerous settlements, either in the form of space stations or people living on other habitable planets. Say there were a million planets settled, which is still a conservative estimate for the number of suitable planets in the Milky Way, and they were settled for only a thousand years each. That’s an æon of human life on other planets. For it to be more probable for us to be here now than there then, it would need the population on each of those planets to average out at less than seven dozen. That is clearly absurd, so we have to conclude that as a species we will never settle on any other planets or build any permanent space habitats, or that our existence here and now just happens to be fantastically impossible.
For this to be the case, we have to conclude that our efforts to go into space are also only ever going to be very minor to non-existent, something which is confirmed right now by the fact that only twelve people have ever visited another celestial body. Even that was difficult because one crew didn’t make it. Now we’re supposed to try again with the Artemis Project, the current plan to go back to where Apollo went. Incidentally, I’ve long thought that one of the issues with the conspiracy theory is that getting there is only equivalent to going round the world ten times. Patrick Moore had a car which had gone further than twice that distance, and the average flight crew probably notch that up in a couple of weeks. Not that it wasn’t an amazing achievement. But humanity didn’t go on to do anything else afterwards, is the issue.
We’re confronted with a problem in the current moment then. It’s looking like there will be more people walking about up there in a couple of years, but if that happens it looks suspiciously like this version of the Doomsday Argument will have been refuted. But before I go there, I want to talk about Brooke Bond.
In 1971, Brooke Bond brought out a series of collector’s cards on the Space Race which started with Sputnik 1 (let’s Russ that up a little: Спутник-1) and proceeded through the various early satellites, planetary missions and the like up to Apollo and then past into the future. I collected the cards and got the book to stick them in. It must’ve been 1971 because it had the pound marked in both shillings and “p”, and they only did that in that year if I recall correctly. Anyway, it was from this publication that I learnt of the plan to send a human mission to Mars via Venus launching in the late ’70s. I remember looking at the years and thinking “1979” and “1980” looked really strange and futuristic, like the numbers on the public library date stamp which had yet to be used. But yes, there was a tentative plan at that point to send astronauts to Venus and Mars which everyone seems to have forgotten. There have in fact been a very large number of such proposals, but I didn’t know that at the time:
Actually, looking at this I realise I got it the wrong way round. They were going to visit Mars first and then do a Venus flyby. My confusion arises from the fact that there were so many different plans to do this. The Russians even considered a Venus mission to be launched in the early 1960s. I remember eagerly awaiting this, in full expectation that it would happen, and the dates passing with nothing to show for them, and how disillusioning it all was. This was a feature of my life at the time. When they found CFCs were destroying the ozone layer and that carbon dioxide emissions were causing climate change, I was convinced that they’d just go, “right, lets take the fluorocarbons out of aerosols and stop using fossil fuels”, and it’s the same kind of disappointment, from which you can see that I wasn’t your typical space nerd or environmental activist, because I suspect rather few people were equally enthusiastic about Green politics and astronautics, but that’s who I am. There is a seamless disappointment there. It’s all part of my same imaginary world, and it was very hard to cope with at the time. I can’t believe how slowly everything except IT progresses, and it’s also weird that IT did advance that quickly compared to everything else. I have certain theories about that, not conspiracy theories but something else, which I’ll leave for another time.
The space-based Doomsday Argument, which I’m going to call “Space Doomsday”, can easily explain why this didn’t happen, although maybe “why” is the wrong word here. The immediate reason the Mars mission didn’t happen was budgetary cuts to NASA in 1970. However, considering our lives as a relatively random sample of human history, we are aware that it’s improbable that human space exploration will ever make much progress, or we probably wouldn’t be here sitting on this single planet where we originated. It’s possible but improbable. The idea that we will in fact end up doing this isn’t ruled out by the fact. It’s similar to the idea that if you have lung cancer, you have probably been a long-term tobacco smoker. That’s something you can reasonably conclude about someone’s previous life given their current condition, although it may also be that they got it from passive smoking or asbestos exposure, for example. It isn’t a dead cert, but it’s probable. Hence it’s probable that something would happen to prevent people from landing on Mars, assuming of course that the expansion into space follows such activities, and in that sense Space Doomsday has predictive power, or perhaps forecasting power. We know we’re here on Earth, so we can reasonably believe the human race does not have a spacefaring future. A slightly less reasonable conclusion is that there will be no human missions to other celestial bodies in our future.
This could potentially lead to a weird version of “Moonlanding” denial conspiracy theory. Obviously I accept humans landed on Cynthia six times owing to not being delusional in that respect, but suppose Artemis happens. I am wedded to the idea that humans will never go there again because of Space Doomsday, so if they do go there I’m tempted to deny that due to it not fitting in with my world view, and the same applies to any planned Mars mission. Am I perhaps a tinfoil hat conspiracy theorist in the making? If someone believed in Space Doomsday in the 1960s, would they have ended up denying the Apollo missions were real? If the news that Artemis does succeed appears in the media and we see pictures from the lunar surface and the rest, it’s fair to conclude that we probably have gone there in a second batch of missions, but one’s belief in Space Doomsday could be so strong that it would lead to K-skepticism. For me, that would be motivated by depressive thinking, but others might have more positive reasons for doubt, such as the idea that it isn’t appropriate for so much money and resources to be spent on space missions when there are enough problems on this planet to be addressed.
Speaking of this planet, there could be a link between these two major sources of disappointment emanating from my childhood. Alternative futures are possible from these. In one, we simply don’t go into space much. Perhaps robotic probes become ever more sophisticated, take over from us, and colonise the Galaxy themselves, or maybe there’s just no impetus to do so and we all become more focussed on whatever’s going on down here. This is a relatively positive future compared to the other one, which is that this apparent lack of concern for environmental disaster simply wipes out the human race in a few years, before anyone gets the chance to go to Mars. This chimes with the apparent, though egocentric, forecast that the last human birth will occur around 2130.
The interesting thing about Space Doomsday is that it seems to have predictive power. For instance, it predicts that there will be a reason why nobody will go to Mars or the Artemis project won’t come to fruition. In fact, Artemis has indeed met with problems. The plan is for at least eight missions, the first two of which won’t involve a lunar landing. Artemis I is an unoccupied test of the spacecraft which will orbit Cynthia and return, splashing down on Earth, next year (2022). Artemis II happens the year after and involves a crew orbiting Cynthia, which would be the first time anyone has left cis lunar space since 1972. 2024 is expected to see humans back on the surface for the first time since Apollo, and a series of missions after that will involve building a lunar base for permanent habitation. This looks like the point of no return for human settlement in space, although it might just not happen or not go any further. But in order to be “scientific” about this, I need to define exactly what I mean by the statement that humans will never settle on other worlds or establish a permanent presence in space. That initial statement looks wrong for a start because of the International Space Station, which is a permanent presence. Otherwise, I’m moving the goalposts, and I might say after Artemis I, “well I never said the hardware wouldn’t work” or after Artemis II, “well I never said nobody would ever leave cis lunar space again” and so on. I need to be more precise, and base it on evidence.
My claim is based on the idea that the total number of human births is likely to be at most 150 thousand million. More than this and the chances of living now rather than later in history fall below fifty percent. In fact, therefore, it’s possible to forecast from this position that the total population of space will always be less than seventy five thousand million minus the population still on this planet. In fact if it were ever close to being that high, that would seem to herald the extinction of the human species for probability-related reasons, which suggests further that there will never be self-sufficient space colonies or that some perhaps solar-related disaster will befall life in this Solar System.
Artemis is supposed to lay the foundations for the eventual exploration of Mars. This in itself means it’s unlikely to succeed, not because that’s over-ambitious but because it means it does in fact appear to be a stepping stone to people living permanently off Earth, which either can’t happen or is likely to end in disaster, or at best peter out. Hence it can be expected that there will be major snags in the program. Now it’s difficult to tell whether I’m seeing patterns where there are none, as any major long-term complicated undertaking is likely to meet with the occasional problem. Thinking again of our hypothetical Space Doomsday person living in the ’60s, they might focus on the Apollo I fire and the Apollo XIII disaster as signs that it wasn’t going to work, that there would turn out, for example, to be insurmountable safety obstacles to strapping three guys into a seat on top of a hundred metre column of high explosive. I mean, who’d’ve thought it? But there were six successful missions as well as more successful translunar incursions (excursions?). It is probably true, speaking from my deeply uninformed position, that the risks taken on those missions were much higher than they would be today, and presumably are on the Artemis program, but maybe not. I confess to not paying much attention to Artemis because I don’t want to be disappointed again, so I don’t know much about it.
There are sound economic reasons for returning, including the presence of metals such as titanium more easily accessible than here and, if fusion ever happens, and that’s another thing which seems infinitely deferred, helium-3 in the soil, and water is now known to be available, in the form of ice in the parts of polar craters in permanent shadow, freeing a base from the necessity of a water supply from Earth. It was detected by the Clementine mission in March 1996, in Shackleton Crater.
The spacesuits for Artemis have been delayed, it was announced this August. This will prevent a 2024 landing, since they won’t be ready until April 2025 at the earliest. That puts it later than the next presidential election, and if for example Trump is re-elected, which unfortunately is still possible it seems, he could cancel the program before then. The current space suits are not intended to be used for extensive periods on the lunar surface, hence the need for new ones. One reason for the delay is budget cuts and another is the pandemic. But you could look at it, rather unscientifically, as a curse or fate. There is reason to deduce that something will always stop it happening because it’s possible that we can be confident nobody will ever go there again or to Mars at all. The details of the cause are apparently not available, but right now they seem to include Trump, the pandemic and budget cuts.
The Artemis program involves the building and transport of infrastructure and equipment separately from the crewed missions. This is a factor in its demise. If it was just about astronauts visiting without setting up a permanent base, it could well go ahead as that’s a less significant step in establishing a foothold elsewhere in the Solar System. Hence the crewed lunar orbital mission is more likely to happen, although this is also a step on the way. It would also be more likely to happen if it wasn’t supposed to be a preliminary to going to Mars. There was a plan, decades ago, for the first astronaut to arrive to start putting together a permanent lunar base, which it’s possible to predict wouldn’t happen for the same reason.
I’m not going to deny that a lot of this post is motivated by depressive thinking, although I’m not actually depressed just now. To counter that, I want to point out that depressive realism helps one perceive unpleasant truths, one of which appears to be that our descendants are trapped on this planet forever. And I’m not even saying that Earth is not a wonderful and beautiful place. It’s for this exact reason that humans should move many of their activities, and for that matter bodies, into space, off this planet, to preserve it and allow it to recover. Moreover, there was always going to be positive fallout from space travel, such as the Overview Effect, the Spaceship Earth concept, the discovery of the possibility of nuclear winter, the reminder Venus gives us of how easily climate change can get out of hand, not to mention the various technological benefits. Nonetheless, some people would see being stuck here as a positive thing, and it has positie aspects. It means, for example, that there is no escape from the effects of pollution, reduced biodiversity and anthropogenic climate change, except that maybe there is for the rich and powerful but not the poor and oppressed.
So wouldn’t it be nice if we had a lunar base, went to Mars and built space colonies for the people left here on Earth?
A Box Of Chocolates 