The Globe Theatre In Space

Yes, I know I’m supposed to be alternating.

I’m not sure how much to make of the idiosyncratic naming scheme for the moons of the seventh planet from the Sun. As a fan of language and word play, they appeal more to me than they perhaps should if I’m just going to be talking about them in a scientific way, but the fact is, there’s the Universe and there’s the person observing the Universe, and you can’t entirely step outside yourself. The rest of the Universe is, in a sense, your mind reaching out to it and placing it within your own private world. It’s part of you. That said, science tries hard to be objective. However, it’s significant to many of us that twelve Americans walked on Cynthia and that people do romantic things “by the light of the silvery Moon”. Cynthia is culturally significant to us.

With regard to the twenty-seven known moons of the planet I’ve been calling Hamlet, it might be a little hard to imagine how such a small system so far away from us could have any consequences for us Earthians. They don’t figure prominently even in the realms of science fiction and astronomy. If we had sent more than one probe to the system, maybe it would be more significant to us all. If it turned out to be the only other abode of life in the system, it would be considered hugely important. There is in fact at least one aspect to the planet which makes it relevant to life here. There is only a weak internal heat source and the Sun makes little contribution to its temperature, leading to computer models of the atmosphere being dominated by the Coriolis Effect. Due to the abstraction of the model from observed conditions, which of course confirm its accuracy, this constitutes yet another refutation of the hypothesis that Earth is flat, because of how the effect operates in our own atmosphere and attempts by flat Earthers to explain this in terms of solar heating (and perhaps lunar cooling!). Even this, though, is something of a niche explanation.

The moons concerned, taken together, don’t add up to much, which is why I’m dealing with them all in one go. Their total mass is less than half that of Titan, and also of Neptune’s giant moon Triton, but this isn’t the same as saying they’re small for two reasons. Firstly, Titan itself is 96% of the mass of everything orbiting Saturn including the rings, so the seventh planet’s moons are actually bigger en masse than all of Saturn’s except for Titan. Secondly, volume, surface area and diameter are counter-intuitive. Our own moon has only 1/81 Earth’s mass but has a diameter a quarter of our planet’s. By the time you get this far out from the Sun, even many compounds gaseous on Earth are frozen solid. Umbriel is probably the warmest moon, because it’s dark and absorbs more light, and has a maximum temperature of -188°C, barely warmer than the boiling point of air. One consequence of this is that the densities of the moons are very low, which means they’re larger than their masses suggest. It’s also interesting to compare the situation here with that in Neptune’s vicinity.

I’m going to reiterate this yet again in case you’re coming across this post without having read any of the others: the moons of the seventh planet don’t take their names from any mythological tradition, but from works of literature, mainly Shakespeare’s plays. I find this refreshing but there is an element of cultural imperialism to this. Then again, the same is true of the dominant Greco-Roman tradition for the other planets, moons and asteroids in the system, but what’s done is done I suppose. There were two widely separated phases of discovery, which is also true to an extent of the other gas giants but in the cases of Jupiter and Saturn the rate of discovery is rather different. Jupiter’s Galilean moons were all discovered in 1610 CE, then nine moons were found between 1892 and 1975, followed by three via the Voyager probes and a spate of discoveries from 2000 on. Saturn’s show a more regular distribution between the seventeenth and nineteenth centuries, a rush associated with the Voyager missions and a further sequence of discoveries from 2000s on as with Jupiter’s. My experience of Hamlet’s moons is that five were known when I was a child, and because one’s childhood experience is just how things are, and one hasn’t yet gotten used to change, that was just how things were. I wasn’t aware of the peculiar naming scheme because at the time they seemed just to be kind of Latinate, for instance Ariel and Miranda, although one is much more likely to come across a human Miranda in everyday life than, say, a Phœbe, and way more likely than meeting someone called Ganymede. The first four were discovered in pairs in the eighteenth and nineteenth centuries, then Miranda in 1948, then we had to wait until Voyager for any more discoveries. After that, Caliban and Sycorax were found in the ’90s, Perdita was discovered using old Voyager data and the rest come from between 1999 and 2003. Since then, no more discoveries have been made but this might be because Hamlet is a neglected planet compared to the others, so maybe nobody’s looking. It is also very dim and distant, so it might be that.

Titania is the largest. This is quite possibly the poorest decision ever in naming a moon. Titan was already known by the time it was discovered and there are different ways of pronouncing it. And how do you refer to something to do with Titania without people thinking you’re talking about Titan? However, we can talk about the place. It’s the largest and most massive of the moons in a system which isn’t particularly large or massive. Here it is:

That slight blurring is probable due to the impossibility of correcting entirely for Voyager 2’s motion blur. About forty percent of its surface has been seen. Like the other moons, Titania doesn’t orbit near the plane of the Solar System due to its planet rotating on its side, meaning that that illuminated surface in the picture remains in daylight for decades at a time, just as the other side stays in night. This means that one pole is somewhere near the middle of the lit portion of that image, in this case the south, because like all such images of the moons, this was captured in 1986. All the large moons are about half rock and half ice, so they’re actually denser than many of Saturn’s, and Titania is both the largest and densest of all of them. All the moons also have largely grey surfaces, Umbriel being darker than the others, hence its name. Titania is half Cynthia’s width and has icy and dry ice patches on its surface. It’s considered likely that it’s differentiated into distinct layers with a rocky core and icy outer layers. There may be a little liquid water inside at some level. There could also be a very thin non-collisional atmosphere of carbon dioxide.

Oberon was discovered with Titania and is slightly smaller, orbiting outside Titania’s path. It’s more heavily cratered. Both are at comparable distances from their planet as Cynthia from Earth. For some time after the pair was discovered, it was thought that there were six moons overall but after many years the others came to be considered spurious, although of course there are other moons. A significant difference between it and Titania is that the latter orbits entirely within the magnetosphere whereas Oberon passes in and out of it. Again, only forty percent of the surface has been mapped. It’s also the outermost large moon. Oberon’s features are named as follows:

The surface has a sheen to it and is slightly red except where newer craters have yet to acquire that: those are slightly blue. This reddening is due to space weathering, where electrically charged particles hit the surface. Unlike all the other large moons, the trailing hemisphere has more water ice than the trailing one. It’s almost exactly the same size as Rhea, which makes me wonder if there’s a peak in moon sizes at about this diameter across the Universe as it’s also quite close to Titania in size. There are apparent rift valleys, such as Mommur Chasma. In the distant past, when the moon was young, processes within it had an influence, namely its slight expansion by about half a percent of its diameter. Mommur Chasma is apparently named after the original French version of the tale of Oberon’s home, «Huon de Bordeaux».

Miranda and Umbriel are probably the most distinctive of the large moons. “Miranda” the word is a gerund meaning “worth seeing”, hence the “-anda” names Amanda – “worthy of love” and Miranda. Samuel Johnson once said of the Giant’s Causeway that it was “worth seeing, but not worth going to see”. Well, Miranda seems to fall into the same category. It is indeed worth seeing but given that only one spacecraft has ever been there, possibly not worth going to see. However, it’s still remarkable. Here it is:

As you can see, it looks rather rough. It has a diameter of 370 kilometres and is therefore on the lower edge of worlds whose gravity is able to smooth them into an approximate sphere. At some point in the past, it was hit by something and shattered into small pieces which then all fell back together haphazardly. There are enormous cliffs all over the moon, including the highest cliff in the System, Verona. Twenty kilometres high, if an object falls off Verona cliff it would take ten minutes to fall to its foot. Although it’s tempting to believe that these cliffs are the result of the shattering, they’re more likely to be due to the same kind of expansion as Oberon’s chasms. The number of craters suggests Miranda was only formed during the Mesozoic, or at least that whatever happened to it took place then.

Umbriel is the only major moon not at least ambiguously named after a Shakespeare character. Instead, the name is taken from Alexander Pope’s ‘The Rape Of The Lock’, where it refers to a “dusky melancholy Spright”, also referred to as a gnome. Clearly the name is related to the Italian and Latin “umbra” – shadow. As well as being particularly dark, Umbriel has a crater outlined in bright white material where a pole would’ve been if it orbited normally, but it so happens not to be situated there because of its primary’s odd axial tilt:

The mere fact that the light ring is at the top of this picture shouldn’t be taken to indicate that it’s at any kind of pole, because the moon rolls round as it orbits in a manner typical of such bodies, but its orientation here makes it look like a polar feature. Its name is Wunda and the feature is ten kilometres wide. Its origin is unknown. The surface is generally dark bluish, although that’s a relative way of describing it along the lines of “black” often being tinged with a cast of a particular hue rather than it being pure black. However, it also seems odd to me because most dark objects in the outer system are red-tinged rather than blue, suggesting that it isn’t the usual tholins that are coating the surface. Nothing other than craters are known on the surface unless you count the ring.

Ariel is the other major moon with an ambiguous name, as it could be named after either Ariel from Shakespeare or Ariel from Pope. Its mass is about the same as all the water on Earth’s surface. It’s somewhat bigger than Miranda and slightly larger than Ceres. It’s half ice and half rock, and despite its name has no washing powder on its surface. That comment isn’t quite as flippant as it sounds because other bodies in the Solar System do have washing soda in and on them, including Ceres.

Not the same thing

What the heck is it about this planet and its system which leads to it having such peculiar names‽

Right, so Ariel is the second closest major moon to its planet. It’s also the brightest per area at around four times as bright as Cynthia, although being twenty times as far from the Sun it only has a four hundredth of the sunlight falling on each square metre in the first place and is well under half the size. Its surface is more varied than the likes of Umbriel, as far as has been seen anyway, with canyons, ridges, craters and plains all present. The chasms are often bowed in the middle rather than flat or tapering, and seem to result from freezing water and ammonia altering the dimensions of the moon. Chasms often become ridges, suggesting that they are a similar response to the freezing of liquids, so the moon’s surface could be seen as a mixture of the wrinkly deflating balloon and the cracks of an expanding soufflé (but without the bubbles). The plains are probably similar to lunar maria, in this case involving the eruption of a thick liquid, possibly a mixture of ammonia and water. There are no large craters, suggesting that the surface is younger than the Late Heavy Bombardment period early in the system’s history. The largest crater is the 78 kilometre-wide Yangoor. Ariel has similarities with Saturn’s Dione.

Those, then, are all the large moons. To summarise that bit of the system, they are in order Miranda, Ariel, Umbriel, Titania and Oberon. Their spacing corresponds to a law similar to the Titius-Bode Series relating to the spacing of the planets, if that is indeed valid. Mary Blagg’s 1913 generalisation of Bode’s Law yielded the formula A(1.7275)ⁿ(B+f(α+nβ)), where A for this system was 2.98 and B 0.0805. Hence there seems to be something orbital resonance-related going on here. Some of them were probably warmer in the past due to having less circular orbits and so more vigorous tides.

I want to mention a slight personal peculiarity at this point. As a small child I used to delight in memorising the names of the moons of the outer planets. This led to the oddness of Jupiter’s moons having their names changed to my considerable confusion in the late ’70s. In the case of “Hamlet”, the seventh planet, the planet whose name one dare not speak, the list was rather short and didn’t really stick in my memory, but oddly it had an extra member according to my unreliable recollection: Belinda. I didn’t think much of this because the subject of those moons rarely or never arose until 1986, and even then it wasn’t all that, partly due to the Challenger disaster. Belinda is a small moon orbiting below Miranda which wasn’t discovered until 1986. I had no knowledge of ‘The Rape Of The Lock’ at this time, so I can’t account for the fact that for well over a decade I thought there was a moon called Belinda when it didn’t even get named until after the Voyager 2 mission. This seems to be rather akin to a Mandela Effect, such as the placement of single releases in my memory being several years different than in reality. For what it’s worth, Belinda is an elongated moon 128 kilometres long by sixty-four kilometres wide and extremely dark, and it may collide with other moons in a hundred million years or so, so it could be a future ring. There are thirteen known moons within Miranda’s orbit and many of them are elongated, although I personally wonder if that’s the reality or whether it’s motion blur. Presumably that’s been taken into account though. These cis Mirandan moons are known as the “Portia Group” and are named Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, (the second largest, at 156 kilometres maximum diameter), Rosalind, Cupid, Belinda, Perdita, Puck and Mab. Puck is the largest, with a diameter of 162 kilometres and was the first discovery after the larger moons, in 1985, by Voyager 2 shortly before it began the main part of its mission. It’s heavily cratered, dark and has water ice on its surface. Because it was the first moon to be discovered, there was time to program the probe to get more information on it than the other small moons. Three of its craters are named: Butz, Lob and Bogle, named after impish spirits in European mythologies.

Then there are the nine known outer moons, which are trans Oberonian: Francisco, Caliban, Stephano, Trinculo, Sycorax, Margaret, Prospero, Setebos and Ferdinand. Sycorax is the largest of these at 157 kilometres diameter. It’s more than twenty times further out than Oberon and is light red in colour. It has its own rotation period of seven hours, not locked to the planet and takes three and a half years to orbit. It averages twelve million kilometres from Hamlet. All of the outer moons orbit backwards with respect to the planet, which itself technically rotates in the opposite direction to all other official planets except Venus. The orbits are not in the equatorial plane. The outermost moon is Ferdinand, orbiting on average twenty million kilometres from the planet and taking almost eight years to do so. Margaret is unique among this group in orbiting in the same direction as the large moons.

When the large moons were first discovered they were numbered in order of their discovery. This was then changed to the order of their distance from the primary because of course they’d change the system because it’s “Hamlet” isn’t it? Hence there are two different numbering systems.

It isn’t that the moons are less distinctive or interesting than those of Jupiter and Saturn, although they may in fact be, so much that little is known about them. The larger ones certainly seem to be more similar to each other than those of the two largest gas giants and there isn’t as much interaction between them. They are also rather unlike the moons of Neptune, which include a major anomalous member. The general impression they give is of a system of remarkably unremarkable moons of average dimensions, although in a way this is surprising considering that they all effectively have days lasting seven dozen years.

I’m not sure what to do next. I will probably more on to the rather similar Neptune, but there might be something interesting going on between the orbits of the seventh and eighth planets so I might also consider that.

Planet Hamlet

Look here for an explanation of the post title. At least for this post I shall be calling this planet Hamlet rather than the silly name. So far as I know, nobody has ever called it that before and it may not function well as a viable official name, although I think it would. Although there may be issues of cultural imperialism, the character as portrayed in the play in question is in a sense global property. On a different note, it has an even lower population than a hamlet.

Hamlet used to fascinate me inordinately as a child, probably for two reasons. One is that it’s blue. In fact, Neptune is if anything bluer, the image above being false colour, but James Muirden the astronomer commented in his book that he definitely saw it as having a blue tinge even though everyone else seemed to see it as green. The border between green and blue seems to be more disputed than most colour differences, and it’s worth remembering that colour terms in other languages often vary, and also tend to occur in a particular order. I presume that Japanese calls the colour in question “青”, as does Mandarin (kind of). The other reason is that for whatever reason, Hamlet is the most obscure planet, being mainly used as the butt of jokes because of its name, which makes it intriguing and a target for the imagination. Hamlet is also only a little denser than water, and at the time of the 1930s (CE) encyclopædia I was getting my info from, its density seems to have been estimated as the same as water, suggesting to astronomers at the time that the planet was a globe of liquid. In 1977, I wrote a story called ‘A Holiday On Uranus’ about exactly that, set in 2177. I remember it fairly vaguely, but in it Hamlet was inhabited by intelligent fish-like beings living in its vast ocean and there was a security scanner used at the spaceport which used terahertz radiation to reveal the surface of the body in clothed people, which was eventually invented for real. Travel to the planet was at near the speed of light. I also imagined slavery in the Saturnian system and cruel and oppressive measures being taken to modify the bodies of Saturnians to make it impossible for them to rebel in an analogy to the Atlantic slave trade. I still have it somewhere I think.

At that time it was still possible to project one’s imagination onto the outer Solar System in such a way, although my view was clearly influenced by the fact that most of what I’d read about Hamlet had been written in the ’30s. Also, in one of those odd random associations one gets as a child, Bing Crosby’s ‘Little Sir Echo’, about a personified echo who was “ever so far away”, always used to make me think of someone living there, and I even went so far as to calculate how long it would take sound to travel the distance from Earth to the planet and back, which is around five and a half centuries. I also imagined a steam locomotive travelling there, which would probably take about a millennium, though that’s a guess. It strikes me that all my imaginings about Hamlet were extremely outdated even for the time I was making them.

Back in Stapledon’s day, and he was chiefly active in the 1930s as far as popular fiction was concerned, the giant planets weren’t considered to be gas giants, but extremely large rocky planets with thick and deep atmospheres. Consequently he was able to imagine Neptune in particular, and also to a limited degree Hamlet, as planets inhabited both by native life and the descendants of life from Earth, and given the increased radiation from the Sun æons in our future, Hamlet has agriculture at its poles, the equator being too hot, suggesting that at that point its peculiar rotation had yet to be discovered.

This brings me to the first real point about the planet: it “rolls around” on its side. Hamlet does not rotate “upright” like most other planets. It doesn’t even rotate at a somewhat tilted angle. Instead, each pole spends a season of the seven dozen-year long orbit pointing towards and at another time away from the Sun, as its axial tilt is 98°. This means that for most of the surface, with the exception of the equatorial region, there are forty-two years of daylight followed by another forty-two years of night. Hamlet does, however, rotate properly every seventeen hours, so at the equator it would have a normalish day with sunrise and sunset. This zone is about fourteen thousand kilometres wide. If it was much closer to the Sun, this peculiar arrangement would lead to very extreme seasons, but Hamlet is actually colder than the next planet out, Neptune, at -224°C. It has the coldest average temperature of any of the planets in the system. This anomalous situation is thought to be caused by the same incident which tilted it so extremely. It’s believed that a major impact or close encounter between a massive object and Hamlet knocked it onto its side and stirred up its atmosphere to the extent that the warmer layers nearer the centre of the planet, where the temperature is about 5000°C, ended up circulating towards the cloud tops and radiating the heat which in other gas giants is insulated from space by thousands of kilometres of not very conductive fluid. It might be thought that the reason is that half the planet is in darkness for forty-two years at a time, but this is not in fact the reason. Hamlet is so far out that it doesn’t really make as much difference to the temperature, and like many outer worlds the internal heat is a major contributor to the climate and weather. However, Hamlet is smaller than the two inner gas giants and has no significant tidal forces to generate heat, so it would in any case have a much cooler interior even without the incident which stirred it up.

When he discovered the planet, William Herschel thought it was probably a comet. It’s remarkable in being the first planet to be consciously discovered in historical times. There is a sense in which Venus was discovered when it was realised that the Morning and Evening Star were identical in the thirteenth century, which also led to it being given that name because the Morning Star was dedicated to the goddess, but an entirely new planet had never been discovered before. Remarkably, Herschel lived to the age of eighty-four, which is the same length as Hamlet’s year. Asteroids began to be discovered about twenty years later. The planet often seems to be passed over. For instance, there are relatively few works of SF which feature it. One exception is Fritz Leiber’s ‘Snowbank Orbit’, a 1962 short story in which the spaceship Prospero ejected from the inner system by an explosion in a battle attempts a slingshot orbit around Hamlet to bring it back inward. This was before such a manœuvre had been attempted for real as far as I know, but is now common, though not round the planet in question. Leiber tends to focus on Shakespeare, so his inclusion of Hamlet in that tale is probably due to its own naming theme. I haven’t read it all, but suspect that the planet only really participates in the plot as a distant “roundabout” rather than a planet in its own right. To be fair, so little was known about the place back then that it might not have had much opportunity to be anything else, although it’s all about imagination and Leiber was substantially a sword and sorcery author as much as an SF one. Cecelia Holland’s ‘Floating Worlds’ novel does have it as a proper location though. I actually owned that book for decades but never got around to reading it before I ended up giving it away, so I can’t enlighten you on its content.

The key concept here, then, seems to be that Hamlet tends to be ignored to a much greater extent than other planets, except for the obvious occasional puerile comment. Is this fair? Is it just that the silly name puts people off taking it seriously, or is there something about it, or perhaps all the other planets, which lends itself to being ignored? Is it the Basingstoke of the Solar System? Come to think of it, is Basingstoke really that boring? Am I being unfair? All that said, Hamlet as a planet, as opposed to our relationship with it, is indeed unusual because of the fact that it orbits on its side, if for no other reason. It’s also the first planet to be found with rings after Saturn, within my lifetime in fact, and its rings are notably different to Saturn’s, being darker, thinner and more widely spaced. Its moons are, uniquely in the Solar System, not marked by any outstanding features. Neptune has the kudos of being the outermost planet if Pluto isn’t counted as one, and for twenty years at a time Neptune really is the outermost due to Pluto’s peculiar orbit. Neptune also has unusual moons and the fastest winds in the system, but I’ll deal with all that when I come to it.

It is, however, worth comparing the two worlds, as they’re probably the two most similar planets in the Solar System. I’ve kind of been here before. Both are roughly the same size, very cold, the same density and have similar day lengths. They also have similar colours and compositions, and their size and density dictate that their cloud top gravity is similar. Although Hamlet is the colder, the difference is only about ten degrees, bearing in mind, however, that ten degrees is a bigger difference at such a low temperature than it is at room temperature and more like a difference of thirty degrees for us.

Here’s the picture I posted last time:

This is Hamlet as it looked to Voyager when it got there in ’86. The equinox occurred in 2007 so this is something like twenty years off from that, a quarter of a “year” or so away from that point. It’s exceedingly featureless and fuzzy looking, unlike the much clearer and more vivid Neptune:

It’s possible that the haze in the atmosphere of the closer planet is seasonal, but this rather uninspiring view is enough to make one understand why it tends to be ignored. After all, just imagine if a space probe costing millions had been dispatched all the way to the place and it had come up with nothing but for the greenish cueball image shown above. Fortunately, Voyager visited all four gas giants and is to date the only spacecraft ever to have visited either Hamlet or Neptune. It took four and a half years to travel the distance from Saturn to Hamlet and at the time it got there, January 1986, the planet was invisible to the naked eye. Hamlet dips in and out of visibility because of its distance and orientation, but is bright enough to be visible as a faint “star” some of the time to people with good eyesight who know where to look. In order to get a good look at Titan, Voyager 1 had manœuvred itself out of the plane of the Solar System and visited no planets after Saturn in late 1980, but Voyager 2 went on to cover Hamlet and Neptune. This means, of course, that the planet didn’t get as much attention as the previous two in any case. There were also imaging challenges. The rings are as dark as coal and the moons are not only dark but also dimly-lit compared to Jupiter’s and Saturn’s. Moreover, the velocity with which Voyager 2 moved through the system marred many of the images with motion blur. This brings up an important issue often raised by conspiracy theorists about NASA. Images taken by space probes are, as far as I know, always processed from the raw form in which they’re received, for this kind of reason. There may be too much or too little contrast, and in this case the problem was that the blur had to be filtered out. I have little idea regarding how this was done, as I would’ve thought that blurring would mean that some features would have obliterated others completely owing to brightness, but maybe not. I do know it seems impossible to get rid of a different kind of blur with processing in that way, namely when things are out of focus, because otherwise an out of focus image could be drawn which would appear to be in focus to someone with myopia, and that doesn’t happen, I’m guessing because of entropy. However, motion blur is not the same thing. Techniques of processing the blur have also improved since 1986, so it’s been possible to extract new information from the data received at the time. In the case of Hamlet I’m tempted to say that it hardly matters because so little detail is apparent, due not to motion blur but the basic appearance of the planet itself.

Another aspect of Hamlet’s appearance is that for human eyes the green-blue colour tends to dominate and make details hard to see. This is similar to the way a clear daytime sky on Earth, so to speak, looks bluer than it really is to many people. This sounds like nonsense, but I have to interject a personal note here that I don’t actually see the sky just as blue, and this is an issue which has come up repeatedly and I haven’t been able to resolve satisfactorily. When I look at a cloudless blue sky in broad daylight, I see large purple “splotches” all over it. These are not directly linked to my vision because they stay in the same parts of the sky when I look around, so it isn’t a question of glare creating an optical illusion due to the blood in my retinæ. It may be connected that in fact the Rayleigh scattering responsible for the bluish colour of the sky isn’t confined to blue wavelengths but actually affects indigo and violet light even more, and I suspect that what I’m seeing is uneven scattering of these higher frequencies. I don’t know why I would notice this more than other people. I wouldn’t go so far as to say that I see the sky as purple or indigo, but it definitely doesn’t look merely blue to me, and for some reason nobody else has ever mentioned this, so I presume they don’t or can’t see it. Nonetheless, if the human eye were equally sensitive to all wavelengths of visible light, the sunlit sky wouldn’t look blue to anyone but more indigo.

I’ve never seen Hamlet with a telescope or anything else, but only via images processed imperfectly for human colour vision. Through violet, orange and red filters, the globe is banded in the same way as Jupiter and Saturn are, though more subtly. The green and blue colour of the atmosphere, however, drowns this out to the unaided human eye. I’ve previously mentioned conspiracy theorists in connection with the question of NASA image processing. Flat Earthers would have the same problem explaining models of Hamlet’s atmosphere as Titan’s, because of the dominance of the Coriolis Effect. Hamlet is very cold indeed, unlike Jupiter and Saturn has only a weak internal heat source, and unlike all other planets in this system orbits on its side. This means that models of its atmosphere correctly show the movements of clouds in a counterclockwise direction dominated by the Coriolis Effect. Note also that these models do not depend on the actual existence of the planet itself, since they’re merely an extrapolation of what happens in a fluid body of Hamlet’s character. The movements are dominated by the movements of the planet itself and not by heat from inside or outside, in spite of the fact that entire hemispheres are daylit for forty-two years at once while their antipodes are nocturnal for the same period, and it might be thought there would be a big temperature difference driving the winds, but there isn’t. This is difficult for flat Earthers to explain because of the rotation of weather systems in our own atmosphere being clockwise on one side of the Equator and counterclockwise on the other.

Hamlet has a number of unusual features which are difficult to explain simply. It rotates on its side, the magnetic field is neither oriented towards the poles or particularly away from them and originates from a location about a third out from the planet’s centre. It’s also colder than expected, and the moons are unusual as well. The most popular explanation is that a roughly Earth-sized body collided with the planet and still has much of its material within it, knocking Hamlet off its axis, changing its composition and causing the formation of carbon monoxide from some of the methane, in other words burning the atmosphere via incomplete combustion due to low oxygen level. Although this is also used to explain the strange magnetic field, I don’t know the connection. Maybe no-one does. This peculiarity also means that unlike any other known planet, Hamlet’s auroræ are equatorial rather than polar, although they do occur around two localised areas on opposite sides of the equator.

One thing I seem to have been right about is that Hamlet contains a vast water ocean, although it is mixed with ammonia, altering its freezing point. Of Neptune, a rather similar planet in many ways, Olaf Stapledon once said, “. . . the great planet bore a gaseous envelope thousands of miles deep. The solid globe was scarcely more than the yolk of a huge egg”. Hamlet and Neptune are by far the two most similar planets in the System, and this is equally true of both. A major fact about both which is almost completely ignored is that it rains diamonds. What happens is that methane is compressed, squeezing out the hydrogen and causing the carbon left behind to form into diamonds under the extreme pressures. These then fall through ever-hotter layers towards the core, where they vapourise, bubble up through the ocean and recrystallise at the top. This also means there may be “diamond-bergs” floating on the ocean. I used the tendency for gas giants to form diamonds in this way in my novel ‘Replicas’, where diamonds have become a monetarily worthless byproduct of the deuterium and helium-3 mining industry on those planets. ROT13’d text spoiler: Zryvffn raqf hc bjavat n qvnzbaq znqr sebz ure cneragf’ erznvaf, fuvccrq onpx ng terng rkcrafr sebz Nycun Pragnhev gb Rnegu, juvpu vf cevpryrff gb ure ohg nf n cenpgvpny bowrpg vf cenpgvpnyyl jbeguyrff. https://rot13.com/. The diamonds may also be floating in a sea of liquid carbon. If this is so, or if there’s a whole geological layer of diamond, it could explain why the magnetic field is so different.

It takes over two and a half hours for a radio signal to pass between Hamlet and Earth, and the round trip is of course twice as long. Voyager 2’s transmitter is about as powerful as the light bulb in a fridge at 23 watts. This is stronger than a mobile ‘phone signal but way weaker than most radio stations. It works over such a long distance because the dishes used are aimed directly at each other, the frequency is free of interference by other human-made signals and the antennæ are very large. This could’ve been mentioned at any point in a number of my recent posts, but it may as well be here. In the case of Hamlet, this single spacecraft is responsible for practically everything the human race knows about the planet, and it relies on that tiny gossamer thread of a radio signal sent in the mid-’80s from two light hours away by a transmitter as weak as a dim filament light bulb. The initial baud rate was about 21 kilobaud, reduced in the end to a mere one hundred and sixty bits per second. They’re pretty amazing ships.

The Voyager mission to Hamlet was overshadowed by tragedy. Its closest approach took place on 24th January 1986, when I was at the height of my arguments with the fundamentalist Christians I met at university (that is relevant, as you’ll see). The Challenger disaster occurred on 28th, and was reported some time in the afternoon. I first heard of it as I was queuing for dinner at my hall of residence, and the kind of “head honcho” Christian student responded that it was “good” because it would persuade people to focus on and spend money on more pressing things. Whereas that’s a common and valid opinion I happen not to share, there’s a time and a place, and I get the impression he was saying that for shock value, which doesn’t seem very Christian by any internal standard. That, then, is my abiding memory of the Challenger disaster, and regardless of the value or priorities of NASA’s Space Shuttle program, the fact remains that seven people lost their lives that day, and of course anyone’s death diminishes us all.

A tangential result of Challenger was that it eclipsed the news from Voyager 2. It was also intimately connected with it in that NASA was inundated with letters requesting that the newly discovered moons be named in memory of the Challenger astronauts. This didn’t happen, even through coincidental Shakespearian characters having the same names. It was a factor in this naming proposal that there was a teacher on board, as many people who were children at the time were watching the launch live on TV due to this connection. It’s also a little-known fact that NASA almost sent Big Bird of Sesame Street, in character, on this flight. In 1988, the IAU, an organisation I currently like less and less the more I hear about it but maybe I’m being unfair, and it is after all an organisation and those are usually bad in some way, voted not to adopt the names of the astronauts for moons because they weren’t international enough. This might seem to make some sense until you consider that they’re actually named after Shakespearean (sp?) characters, which are of course associated with England, so their decision didn’t actually make much sense. However, at least some craters on the far side of Cynthia got named after them.

Hamlet has rings. Although they seem quite different to Saturn’s from a distance, close up pictures are hard even for experts to distinguish between at first glance once the image’s dynamic range has been boosted, because they show the same ringlet structure and there are also at least two shepherd moons, Ophelia and Cordelia. The rings are labelled using Greek letters and numbers, apparently without particular regard to their order. From inner to outer they’re referred to as ζ, 6, 5, 4, α, β, γ, δ, λ, ε, μ and ν. I presume this anomalous order is connected to their order of discovery because the way I remember them from the early ’80s they were named from α to ε. This also seems to continue the tendency to call things to do with the planet odd names, as it seems more logical either to number them or give them letters but not mix the two. The outermost two are red and blue respectively and the rest are dark. The first five, α to ε, were discovered on 10th March 1977 when the planet crossed in front of the star SAO 158687 and it blinked on and off regularly on either side of the planetary disc. However, a ring had been reported much earlier, by William Herschel, although this may have been imaginary because they’re very dark. The ν (Nu, not “Vee”) ring is between the moons Rosalind and Portia, so they also count as shepherds. The fact that most of the rings remain very narrow but don’t have shepherds is unexplained. Before their discovery, only Saturn was thought to have rings. After Jupiter was also discovered to have a ring in 1979, the question was whether Neptune would be the odd one out in lacking them. From that point onward, I assumed Neptune had them. Nobody knows what they’re made of, except that they can’t be ice, because their colours are unusual and don’t yield definite spectra to go on. Their darkness suggests they’re carbon-rich, and in conjunction with the probable diamond-bergs and liquid carbon ocean show that Hamlet is well on its way to being a carbon planet.

Most of the light is reflected by the ε Ring, which is also the most elliptical and the one closest to the equatorial plane. It’s brighter in some areas than others due to that eccentricity and varies in width. It’s possible that this variation translates into arcs – curves – rather than rings for other planets, perhaps orbiting other stars, or maybe Neptune. I can assure you that by the time I come to Neptune I will know if this is so. This is the ring with the first discovered pair of shepherds. The next brightest rings are α and β, which also vary in width, being widest 30° from their furthest points from Hamlet and narrowest 30° from their nearest. It’s probably coincidence that these angles correspond to those of the planetary magnetic field, or if not, something to do with a similar but separate dynamic process. Both these rings are somewhat tilted and are ten kilometres wide in some places, which raises the issue that they were detectable from three milliard kilometres away even though they were smaller than the Isle of Wight. The γ Ring (I’m just going to deal with these in alphabetical order, which means mentioning the 1977 ones first) is narrow, almost opaque and thin enough to make no difference to stars crossing when it’s edge on. This also means it isn’t dusty. The inner edge particles orbit six times for five of Ophelia’s orbits, so there seems to be a relationship there. As for δ, it’s circular, slightly tilted and may contain a moonlet because it seems to have waves in it. It has a more opaque and narrower outer part and a wider and more transparent inner side, which seems to be dustier.

Before Voyager 2 got there, the team who discovered these first five rings found a further three rings by the same method. For some reason these are known as 4, 5 and 6 even though five were already known by that point and there was a Greek letter naming scheme going on from the same team. I don’t understand this, but there it is. Voyager 2 found another two, fainter, rings, the naming scheme going back to Greek letters, and in this century the Hubble Space Telescope found two more. Rings 4, 5 and 6 are up to dozens of kilometres away from the equatorial plane and are inner and fainter to the ones discovered in ’77. They’re also narrower and don’t occult starlight edge-on. The μ Ring is blue and contains the moon Mab, around which it’s also brightest so the chances are it’s made of bits of that moon. These rings are dusty. Finally there’s 1986U2R, because of course it would be called that wouldn’t it?

The rings don’t form a stable system and given what’s known about them should disperse within a million years. However the fact that all the other gas giants have rings suggests either that having rings is normal for such planets or that they’re temporary but very common. Hamlet’s system generally, including the moons, is not so dominated by ring-related factors as Saturn’s although there are several harmonies, operating between small inner moons and the rings rather than the larger classic moons observable from Earth. A moon the size of Puck would be enough to provide the material for the rings, and Mab is actually currently breaking up and forming another ring, so it isn’t that peculiar. There are probably moonlets up to ten kilometres across within each of the rings. I presume the dimness of the sunlight out there combined with the darkness of the satellites and other material makes them harder to detect optically than small moons of Jupiter and Saturn.

Getting back to Hamlet itself, it’s methane which gives it that colour, but the atmosphere is in fact mainly hydrogen and helium like the other gas giants. It’s the second least dense planet and has a cloud top gravitational pull of only 89% of our sea level gravity. There are four layers of cloud corresponding to increasing temperature and atmospheric pressure. At slightly above sea level pressure, there are methane clouds. Considerably further down are the deepest clouds which have been actually observed, where the pressure is equivalent to the Earth’s ocean’s sunlit layers’, and are made of hydrogen sulphide. Appropriately for the planet’s official name, these would stink of rotten eggs. These share the layer with clouds of ammonia, which has an acrid, stinging odour. Below that is ammonium hydrosulphide, and finally, at a level where the pressure is equivalent to about four dozen times our sea level pressure, there are clouds of water vapour. The atmosphere is probably the most featureless of any solar planet’s, but does show the occasional white cloud, as can be seen in the photo at the top of this post. It’s also quite clear compared to all the other gas giants’, Titan’s and Venus’s, though not ours or the Martian one. I would expect there to be a level where one would find oneself completely surrounded by blue-green with various species of cloud. There are also traces of complex hydrocarbons as would be found in mineral oil and natural gas on Earth. Unlike other collisional atmospheres, Hamlet lacks a mesosphere, which is normally found between the stratosphere and thermosphere. There is a hydrocarbon haze in the stratosphere.

The chief distinguishing feature of Hamlet’s atmosphere is its featurelessness. Voyager 2 only detected ten clouds over the entire planet as it flew past. All the other gas giants have more stuff going on in theirs, and this is probably why it took so long to work out its rotational period of seventeen hours. There is a whiter polar cap from around half way between the equator and the poles, which swaps over between north and south as the orbit wears on. Voyager 2 was unable to observe the northern hemisphere because it was night there when it passed, so not only has Hamlet only been visited once but also half of it hasn’t been observed close up at all. In the decade or so after Voyager left, things started happening in its atmosphere but of course they couldn’t be seen as well as they would’ve if they’d taken place when it was there. I feel like there’s a kind of theme emerging here. Also, astronomy has only been advanced enough to make much meaningful sense of what’s going on since the 1950s, which is less than an entire orbit ago, so a whole cycle of seasons has yet to be observed. There has been a dark spot like the one on Neptune, and there are thunderstorms. It’s also possible that there’s a convection layer blocking the internal heat from the outer reaches of the planet.

So that’s Hamlet, such as it is. Next time I’ll be talking about its moons. I have two questions for you though. Did you feel that avoiding the name “Uranus” made you feel differently about this planet? I’m not sure about calling it “Hamlet” either, but that does at least circumvent the issue. Could you think of a better name or is it a bad idea to fixate on it so much?

By Any Other Name

What’s in a name? If you’ve been following this series, you probably have a good idea which planet comes next. I’ve done Saturn, its moons and the centaurs between Saturn and the next planet, so you will be aware that this leaves me with little choice but to post on the seventh planet of the Solar System, and the first one to be discovered since the invention of the telescope. We all know what its official name is, and how annoying that is.

I’ve already insisted on calling the large satellite which orbits Earth on which astronauts landed at the end of the 1960s CE and into the ’70s, which tends to light up our nights and occasionally covers the Sun almost perfectly, Cynthia. There were other choices, some of which may even have been better. I personally like Selene for example. In fact in that case there were so many choices that it was hard to make a decision. This is unsurprising, since any sighted person would be familiar with the body in question. Not so with this other planet, although intriguingly it is visible to the naked eye on occasion and in days of yore, perhaps even in the Palæozoic, it would’ve been clearly visible to many animals, so the usual statement that it was first discovered on 13th March 1781 is quite anthropocentric in a way. This opens up another much more remote possibility: were humans the first culturally-oriented entities to notice it, or did some starship come by back in the Proterozoic or something, and note its presence? The reason I mention this is that this planet is unusually afflicted by its current official name, and for us this is very significant.

The initial choice wasn’t much better. William Herschel chose to call it Georgium Sidus – “George’s Star” – after King George III. Today this seems like a weird thing to do and it took almost six dozen years for today’s name to be accepted. Garbled internet lore has it that it was called “George”, but this isn’t actually so. There were also a number of other names, but Herschel naming it after his patron seems divisive and not conducive to international coöperation in science. Then again, Virginia was named after Queen Elizabeth and so forth, so it was common practice during that long period of history, and there are also the Sidera Lodoicea.

There were other suggestions. One was actually “Neptune”! This was surreptitiously to celebrate British sea power, so maybe it is just as well that didn’t happen. Another possibility considered was “Oceanus”. Both of these refer to its green-blue colour as well as other things. Being the first historical instance of a planet being discovered, there seems to be an element of what TV tropes calls “Early Installment Weirdness” about the naming. People didn’t have a proper precedent as to what to do about a novel astronomical discovery of this kind. It was initially supposed to be a comet, since these had been encountered before. The moons of Jupiter and Saturn had established a precedent for naming after Greek mythical figures, and this was eventually followed. The planet was dubbed “Uranus”.

There seems to have been a long period in history during which names which are regarded as embarrassing and silly nowadays just weren’t. This applies in particular to surnames and this doesn’t even seem to depend on semantic drift. Whereas I can easily believe that a surname such as Pratt has only become potentially embarrassing recently, there are other names whose pedigree of ridiculousness must be much longer. I should point out here that my own surname is annoying and ridiculous in an English-speaking context, so maybe this has led to me focussing a lot more on this planet’s name than usual. It does seem to suggest that people’s senses of humour, if this can be regarded as more than puerile, change as time goes by. Just to state very clearly what the issue is, there are two ways of pronouncing “Uranus” in English. One is the older pronunciation of “your anus”, which I probably used up until about 1980, and the other, which initially seemed better, has turned out to be heard as “urine-us”. So you can’t win. One way or the other it’s gonna sound stoopid.

It might be thought that this doesn’t really matter. However, imagine you’re a NASA employee or an astronomer going up before some kind of board or committee holding the purse-strings and asking non-specialists, or just non-astronomers, for funding into a mission or research into this planet. One might hope that this would have no bearing on the success of such a bid, but it’s alleged that in fact there is less funding and focus on the planet than might be expected, and if that’s so, the name may not be free of consequences. Or, it could be that the planet and its moons are just harder to reach or less interesting than the other planets and moons. Jupiter and Saturn may be grabbing attention though, and this in itself could be connected to naming.

This planet is the first to be given a Greek rather than a Latin name in international nomenclature. In languages which use Chinese characters it’s known as 天王星, “sky king star”. This actually has the word “wang” in it in Mandarin, but unsurprisingly this is not a double entendre in that language, at least for what it is in English.

It doesn’t end there, although the next bit is a little less well-known. On the whole, moons, planets and asteroids within the system had been named from Greco-Roman mythology. This is quite questionable in some ways but typical of Eurocentric culture, and it extends to much international technical vocabulary, in the sciences and elsewhere. Steps have now been taken to name more recently-discovered objects in other ways, for instance from Inuit, Shinto and Norse traditions among others. Hence, for instance, ʻOumuamua and Sedna. Oddly, the moons of the seventh planet were an early example of a break with tradition which occurred nowhere else for quite some time although it was still Eurocentric. None of the moons have names primarily from European classical mythology, and they never have had, although many are Latinate in form. Instead, they’re mainly named after characters from the works of Shakespeare and Alexander Pope. The first two discoveries, by Herschel himself, are Titania and Oberon. Of these, the first is, I think, a poor choice, partly because it’s too similar to Titan and the associated adjective is Titanian, which many might confuse with the one for Titan, and partly because it tends to be pronounced in all sorts of weird ways such as “tittan-EYE-a”. Once that precedent had been set, two more moons were discovered in 1851 by Lassell – Ariel and Umbriel. Umbriel is, so far as I can tell, the odd one out name-wise, since it’s named after the “dusky sprite” in Pope’s ‘The Rape Of The Lock’. Kuiper continued the tradition in 1948 with Miranda. These are all the relatively large spheroidal moons. Voyager 2 then discovered ten more in 1985-6 when it visited the planet. By that time, Voyager 1 had manœuvred itself around Titan to get a better look and had left the ecliptic, so it would have no more planetary encounters, so it was entirely down to Voyager 2. These moons are named Puck (the sole moon discovered in ’85), Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind and Belinda. These were followed by Caliban and Sycorax in ’97, then one more moon from Voyager data two years later known as Perdita. The remaining moons are called Setebos, Stephano, Prospero, Trinculo, Cupid, Mab, Margaret, Francisco and Ferdinand. Not being an Eng Lit bod, I only recognise some of these names from Shakespeare but Sarada assures me that all of them but Umbriel are Shakespearean.

This, then, provokes a further couple of suggestions regarding the name of this planet. It still draws from European culture, but it also circumvents the “urine/anus” problem. It seems to me there are two possibly appropriate choices for Uranus here. One is to call it Shakespeare. This is problematic in that it’s then an entire planet named after a real person. The other, also a real person but fictionalised by Shakespeare, is to call it Hamlet, in which case it would go back to being named after a royal, based on the Scandinavian legend of Amlóði. This figure may or may not be historical. Hence this is my proposal, and by the way I probably won’t even follow it myself: change the name of Uranus to Hamlet. This would, so far as I can tell, completely solve the silly name problem, and I can well imagine someone sitting down in front of a board of some description and proposing a mission to Hamlet without a single snigger in the house.

Next time I will actually talk about Hamlet the planet itself.