The Self-Similarity Of Land Or Pareidolia?

If you’re British, have good eyesight and are more than about fifty, the chances are you will remember this station ident. Back then of course, nobody knew the words “station ident” even though there were about eighteen of them, mainly for ITV companies, in this country. They’re an interesting topic in themselves, but not one I want to cover today.

What I want to illustrate probably works best with a short video clip:

As humans, we have a predeliction for discerning patterns everywhere, even where those patterns are not significant. This clip used to trigger that in me, but what I’m not clear about is whether they’re important. The black and white image emphasised the contrast for me, with black oceans clearly outlining the white continents, and it seemed to me that the Atlantic Ocean looked like a kind of triangular face looking west, which was also quite similar to how the Indian Ocean west of the Indian subcontinent looked. But of course, this could just be nothing. Maybe younger children are more likely to pick up on patterns compared to adults, but it’s still with me whenever I look at a map or globe of the world.

There are other examples. For instance, Afrika and Madagascar and the Indian subcontinent and Sri Lanka are both roughly triangular landmasses tapering towards the south with a somewhat rhomboid island to their southeast. Corsica and Sardinia are also somewhat similar islands. South America and Afrika, as well as fitting together due to having both been part of Gondwana in prehistoric times, are again both roughly triangular landmasses tapering towards the south. The same patterns repeat over and over again on the map. Another one I noticed recently which probably is spurious is the apparent similarity between the coastline of Europe and that of southwestern Great Britain. In this case, South Wales corresponds to Scandinavia, Land’s End to Iberia, the Lizard to Italy and the Isle of Wight to Crete. I’m pretty sure this one is nothing though, particularly when one considers the proportions.

All that said, one of the sources of fractal mathematics was the “Coastline Problem”. This was based on the realisation that measuring a coastline would vary according to the length of the ruler you were using. Great Britain on the crudest scale is roughly triangular, with a very approximate perimeter of 2 800 kilometres. A “ruler” able to produce a very crude but recognisable map of this island, with a length of about a hundred kilometres, yields a coastline of about 3 500 kilometres. According to the ‘CIA Factbook’, the perimeter is around 12 429 kilometres. At this point, one might find that if a ruler a mile, nautical mile or kilometre in length were to be used, different figures would be arrived at, so whereas it says 12 429 kilometres or 7 723 miles, which is correct as far as converting units is concerned, if the coastline had actually been measured twice, once in miles and the other time in kilometres, the results would not be convertible and the length in kilometres would’ve been greater. The same applies to millimetres, only much more so. One of the results of this is that it’s entirely possible to come up with similar figures for the length of the coastline from Aberystwyth to Hayling Island and Vingsand in Norway to Θεσσαλονικη by judicious choice of the right measuring sticks. Alternatively, even with the same yardstick the lengths could in theory be the same, and this is particularly plausible when comparing a fjord-rich coastline with a particularly smooth one. Also, if one considers the Mandelbrot Set, mini-versions of itself are found all over which are somewhat “morphed”, with larger regions minimised and smaller ones maximised, and this could happen to a coastline, but if that kind of thing’s allowed, it appears that anything could be made to fit.

The processes leading to the formation of the islands of Sri Lanka and Madagascar are entirely different. Madagascar is the result of rifting in the Afrikan continental plate causing it to calve off to the side like an iceberg, though one attached to the ocean bed of course. Sri Lanka has existed since Precambrian times in that position relative to the subcontinent and was joined to the land by an isthmus until recently, and is also in the centre of its plate. Nonetheless they both look superficially similar. Is it possible that there is another factor involved which leads to this kind of similarity?

As far as I can tell, although there are other continental archipelagos such as Indonesia and Japan, none are very similar to the islands I’m currently sitting in. That said, comparisons have been made between Japan and Great Britain in other ways, comparing Hokkaido and Scotland on the one hand and Wales and Shikoku on the other. Kyushu is also compared to the Six Counties on this map, but there isn’t an extra bit of Kyushu to be taken into consideration, and Scotland is no longer a different island to the one with England on it, although it was in the geologically distant past. Moreover, Sakhalin could be thought of as part of Japan geologically although there is no similar large landscape north of Great Britain which fills that rôle. That said, there are many similarities between Japan and Britain. Both have languages which are written non-phonetically under the influence of a powerful continental neighbour, both have a sense of reserve as part of their national character and both have an official state religion. To what extent, though, is this cherry-picking? This is what I’d like to get to the bottom of in all of these.

Probably the largest example of this in Earth’s geography is the fairly minor similarity between Afrika and South America. This is of course helped by the fact that they both used to be joined along an entire coastline before the breakup of Gondwana, but there are other factors. Both are roughly triangular continents straddling the Equator with a bulge in the north and a consequential human-impenetrable region in that bulge. This last point is stretching it a bit because hot deserts and tropical rain forest are opposite ends of the spectrum regarding rainfall, and the picture is complicated by the presence of rain forest in the Congo. There’s a possibly rather fruitless question regarding which bits of Afrika and South America correspond. The Amazon is in a sense the Congo of South America and there is no corresponding huge desert, although there are deserts in southern South America, none of them are that similar to the Kalahari. The Atacama is much drier and Cabo Polonio is a cold desert. The Andes are also very important for South America and there is no corresponding range in Afrika. One thing they do have in common is a thin piece of land linking them to a larger continent to the north. One might expect all of these similarities would have led to similar histories and ecologies, but it isn’t clear that this has happened. For instance, the Sahara Pump, if it happened, led to a distribution of the Afro-Asiatic language family across the Sahara and to the south about to the level of the Horn of Afrika and also into Asia in the form of Arabic, but nothing similar happened in South America. There are anteater-like animals on both continents in the form of anteaters themselves in South America and aardvarks in Afrika, and pangolins and armadillos are somewhat similar, but I don’t think there are any Afrikan “sloths”. Both of them, though, have been subjected to colonialism, although only Afrika lost people to slavery abroad due to imperial powers. Both have Hispanophone, Lusophone, Francophone and Anglophone nations, but South America is dominated by Portuguese and Spanish to a much greater extent. A lot of the differences are to do with South America being situated further to the south than Afrika, although there is of course a big overlap.

It’s conceivably instructive to look at Venus and Mars with flooded lower altitudes to see if the same kind of land forms can be identified. This is Venus:

and this is Mars:

(c) Aaditya Raj Bhattarai

There is a fairly clear problem with comparing either of these with Earth. In fact there are several. Both of these maps are based on the idea that 71% of the surface is covered in water as it is on Earth at the moment. However, this doesn’t mean they’re proportionately similar. That is, given that Mars is half Earth’s diameter, a proportionate amount of water would be about an eighth of ours, but that wouldn’t provide 71% cover, and on Venus, which is slightly smaller than Earth, the cover is provided by far less water because there’s less variation in altitude, possibly due to melting mountains (that’s me, not science). Taking the Martian map first, the planet is fairly neatly divided into highland and lowland regions in the south and north respectively, and again this is not a scientific judgement but I think of Mars as consisting of a single continent plus a single ocean due to its size not allowing for anything more complex. Also, the terrain illustrated depends on the absence of plate tectonics. Tharsis in the west of that map is a complex of huge volcanoes caused by a hot spot which doesn’t move and has caused a build up of a massive plateau heavy enough to have cracked the land to its east, which is the blue channel referred to as Noctis Labyrinthis followed by the great canyon, here below sea level, called Velles Marineris or Mariner Valley. Also clear is the large depression Hellas, visible on the eastern side and possibly the antipodes of Tharsis. Having a thin atmosphere, Mars shows obvious craters in the highland “continent” which wouldn’t be there if it genuinely had large bodies of water and rain eroding its surface. Therefore there isn’t really anything similar to the kind of land shapes found here.

Turning to Venus, at first glance the planet looks much more like Earth. The eastern side of the northern continent even looks rather like Siberia. However, there are many more approximately circular “islands” than there are here and the oceans are very different, being much shallower and lacking the oceanic ridges characteristic of Earth with its tectonic plates and continental drift. There are also a lot of archipelagos including relatively large islands and intermediately-sized masses of land between large islands and small continents.

Both these maps show no sign of water erosion, and there having been no continental drift the land is not like it is on this planet. Water also propels plate tectonics. It might be more informative to turn to Titan, since that alone in the solar system has both land and bodies of liquid on its surface like Earth, and it looks like this:

Like Mars, Titan’s size must be borne in mind. It’s a little smaller than Mars but its composition is very different, having substantial quantities of water ice in its make up. It’s difficult to work the consequences of this out because we’re used to water ice near its melting point, whereas Titanian water ice would be mixed with rock and therefore kind of “muddy”, and also much harder due to being well below the temperature of our South Pole in midwinter. Nonetheless, the solid surface material on Titan is eroded in a similar manner to how water erodes our rocks:

Those are pebbles, possibly of water ice (frozen water) which have been rubbed smooth by liquid ethane and methane. Titan always faces Saturn and takes just over a fortnight to orbit the planet. It’s also a lot colder than Earth and its atmosphere is thicker and therefore carries heat around the moon more effectively. Therefore, even though the surface temperature of Titan is below -180°C, it behaves as if its climate is tropical, bearing in mind also that the boiling point of methane on Titan, with its higher atmospheric pressure, is -155°C. Moreover, although we tend to think of temperature as a linear scale, it often makes more sense to see it as exponentially colder and to scale it relative to the temperatures we’re used to, because absolute zero, -273.15°C, is actually infinitely cold as it can never be reached and it always takes the same amount of energy to halve the temperature. Titan is only 5°C warmer than the melting point of methane but since its surface temperature is around a third of Earth’s, that’s equivalent to our whole planet being at 15°C. However, water is also a highly unusual substance because it expands when it freezes, which is not unique as bismuth and gallium, for example, also do it, but there are unlikely to be any celestial bodies with oceans of bismuth or gallium. Water also turns white when it freezes, which reflects heat and therefore tends to produce a feedback effect, cooling it further. Erosion and weathering from ice are therefore different from erosion would be from frozen methane. For instance, water can seep into rocks, expand on freezing and force rocks apart, and naturally glaciers can carve out U-shaped valleys and fjords. Titan would not have fjords or that kind of erosion. Nor does it have continental drift because that too requires water, meaning that there is more opportunity for erosion to smooth the surface without it being replaced by volcanism, which is also stimulated by continental drift. There are faults on Titan, but they don’t follow continental plates and there may also be volcanoes, but nothing like the “Ring Of Fire” around the Pacific Basin on Earth. Consequently something like the island of Madagascar cleaving away from Afrika won’t happen, although that doesn’t mean there wouldn’t be islands off larger landmasses on such a world.

I don’t know about you, but I find that map of Titan difficult to read. I presume that the darker patches are exposed liquid and the lighter patches land, but I’m not sure. This set of pictures, however, may make things clearer:

Despite what I said, that looks quite fjordy to me. There are also rivers running into it. This is Ligeia, a lake about a third the size of the Caspian and is the second largest body of liquid on the moon. This should be put in perspective in that in terms of proportion of coverage it’s more than four times larger and therefore bigger than the Caspian by scale. The largest body is Kraken Mare:

Kraken Mare has an approximate area of half a million square kilometres, making it almost twice the size of the Caspian in absolute terms but still only a small fraction of the size of the smallest ocean, the Arctic, even in proportion to the size of the moon. The essential difference between Titan and Earth is therefore that whereas Earth has land surrounded by continuous liquid, Titan has liquid surrounded by continuous land, meaning that comparisons of land forms are only meaningful for islands in its lakes and seas, although the shapes of the lakes and rivers are more meaningfully compared between the two worlds. The rivers of Titan seem to be much more subject to tributaries than those of Earth, which may be what gives the moon’s lakes and islands their fjordier appearance. The peninsula jutting out into the lake near the bottom left does have a larger headland to it rather than just being a finger of land, which is superficially like Iberia except that in that case the land used to be an island that collided with the rest of Europe. On the whole, it doesn’t look that familiar though. It also occurs to me that the density and viscosity of a mixture of liquid methane and ethane could be somewhat different, although the molecular weight of methane is very close to that of water. Gravity must also be a factor.

Without another Earth-like world to compare it to, it’s difficult to say what’s happening and what forms are likely or unlikely, but the considerations I’ve had to make here might narrow down the conditions somewhat. They seem to include the following:

• Relative quantity and depth of liquid.
• Coverage of surface. I’m guessing that more than fifty percent of the surface must be covered for there to be reliable continents and extensive islands.
• Plate tectonics. A lot of what’s visible on the surface of this planet is a manifestation of continental drift, which allows land to be rebuilt via volcanism and islands to surface, submerge and so forth.
• Density of liquid.
• Weight of liquid. This is not the same as density because it’s related to gravity.
• Coefficient of expansion. There may or may not be any fjords on worlds whose oceans are not made of water.
• Difference in density of liquid and solid components of the surface.
• Hardness of solid components.
• Thickness of the atmosphere – a thinner atmosphere would lead to more craters which would probably flood, although they would also be eroded quite quickly.

I haven’t been able to come to any conclusions yet about this. I can see that a supercontinent might fracture into roughly triangular continents, that island chains form from both continental drift and volcanic hot spots moving around relative to plates and various other things, but to be honest I’m no closer to being able to decide whether the apparently similar land I saw on the BBC globe in the early 1970s was mere pareidolia or a pattern which exists independently from human perception.

The Ringed Earth

View of Earth’s rings from California. Image created by Kevin Gill

Unlike the Planet Zanussi, we have no rings circling our home planet. Glancing at the rest of our Solar System, we appear to be able to discern a pattern. The inner planets Mercury, Venus, Earth and Mars have no rings. The outer gas and ice giants Jupiter, Saturn, Uranus and Neptune do have rings. From this it would be easy to conclude that rings are the exclusive preserve of either the outer Solar System or large planets. This is, however, probably not so, and will certainly not be so a few million years from now.

Until the late 1970s the only known ringed planet was Saturn, whose rings are particularly bold and striking. In 1977, a star was observed to blink on and off a number of times before Uranus passed in front of it, and again the same number of times on the other side at the same intervals. Later, one of the Voyager probes managed to get a good photo around the time it was leaving the orbit of Saturn, of the whole ring system. By that point, the same spacecraft had discovered that Jupiter too had rings, although much less substantial ones than Saturn. Then there seemed to be a long period, relative to my life anyway, when it was just those three, and it seemed odd that Neptune wouldn’t have them but there was not yet any evidence. After the detection of rings around Uranus, astronomers started to look for Neptunian ones but were unlucky with the placement of the planet during the 1980s because it was in a particularly blank part of the sky, and since it takes around a hundred and sixty-five of our years for it to get round the Sun the opportunities to observe occultations of stars are rare compared to Uranus, which moves against the dark background more than twice as fast. That said, there was an occultation, but it was a freak event caused by a tiny moon called Larissa which wasn’t discovered until Voyager got there. It’s under a hundred kilometres across, so the chances were minute.

It has also emerged in the meantime that some asteroids have rings. This seems to be because they tend to be “rubble piles” – bodies consisting of lumps of solid matter held together by a weak gravitational field but not compacted into a single solid body. Amalthea is probably like this too. Consequently, particles can get kicked up from their surfaces by various gravitational events or collisions which then orbit and end up forming rings due to collisions among themselves or momentum from the spin of the asteroid. That’s my guess incidentally. I have no idea if it’s actually true. For the same reason, the anomaly of Earth having an unusually large moon for its size may remain anomalous, because although there are many smaller bodies with relatively large satellites, notably Pluto, this may reflect the fact that their gravity is lower. Again, that’s me guessing. Pluto’s moon Charon is, though, 12% of Pluto’s mass, which means that if the situation were replicated here our moon would be larger than Mars.

I mentioned previously that there will one day be a ringed planet in the inner Solar System. That planet is Mars. Mars is the only planet other than Earth inside the asteroid belt with its own satellites, in the form of Phobos and Deimos. I’ve long thought of them as captured asteroids, and I’m sure they are, but the reality seems a bit more complicated. Mars may have had rings in the past and may have them again in the future. I need to explain the Roche Limit.

We’re accustomed to thinking of objects orbiting, say, Earth as having no gravity. We think of them as being in free fall. On the scale of something like the ISS, this is so close to being true it’s probably not worth considering that it isn’t. In fact, if a rigid body is orbiting a planet, only its centre of gravity is likely to be at zero G because the rest of it isn’t following the exact orbit. The further from the centre of gravity you get, the stronger the gravity becomes. This would be noticeable on a human scale if an astronaut was orbiting a neutron star, for example, because in that case the effect is so extreme that the gradient of increasing gravity is too, and a person in that situation would be quickly torn to pieces. This effect is also true of Earth in both the lunar and solar gravity fields. The core of the planet, more or less, is orbiting the Sun, but the surface is always slightly deviant. This puts minor strains on the crustal rocks, which move up and down by a few metres twice a day, but since they’re solid the effect is quite small. The same does not apply to liquids, notably the ocean, and consequently the level of the sea goes up and down twice a day, somewhat influenced by the Sun’s gravity but much more by lunar gravity. These are of course tides, and this kind of gravitational influence is called “tidal”.

If a body, such as a moon, has a sufficiently large orbit it can be large and hold together under the tidal forces applied to it by the planet, but if it’s within about 2.44 times the planet’s radius, known as the Roche Limit, it will be pulled apart by the tides. Amalthea is somewhat affected by this. The ends of the moon in the orbit have such a low gravity that rubble and dust from the surface is constantly leaving and entering into orbit around Jupiter, forming a ring. Clearly if Cynthia (“the Moon”) were sitting on the surface of this planet, assuming it wouldn’t crash through the crust, which is what would actually happen, it’s easy to see that it would break up and turn into a pile of rocks, which would still be too high and therefore collapse under its own weight until it covered Earth’s surface in tiny moon fragments.

Something similar to this seems to have happened on one moon in our Solar System. Iapetus, also distinctive in being almost black on one side and abruptly changing to almost white on the other, has a huge ridge running round its equator which is thought to be a collapsed ring.

The Martian moons are in highly unstable orbits. Over a period of many millions of years, the orbits of all planets, dwarf planets, asteroids and moons in the Solar System are unstable, but this is particularly true of Phobos and Deimos. Phobos is covered in streaks where Martian gravity tears at it. It will be torn apart and form a ring in something like fifty million years. This is actually something like the sixth or seventh time this has happened, because it appears that this is a regular process, and each time Phobos moves outwards, having lost most of its mass to form an increasingly tenuous ring.

This is crucial because it shows that small planets in the inner Solar System could in fact have rings like their big sisters. Mars is in a sense a special case because it’s next to the asteroid belt and can more easily capture asteroids which then get smashed up by tidal forces, but it’s also the second smallest planet and this is significant. It’s also significant that ring systems are generally temporary. We happen to be living at a time when Mars lacks rings and Saturn has particularly visible ones. The lower reaches of the rings are braked by the planet’s upper atmosphere and constantly rain down onto the clouds at a rate of about 2 500 tonnes a minute. This could explain the Crêpe Ring, which is a fainter inner ring closest to the atmosphere, clearly losing particles. They’re due to be gone completely by 300 million years from now, which is around seven percent of the age of the Solar System, suggesting that they haven’t always been there. On the other hand, Mars does intermittently have rings but they regularly appear and disappear. It’s more or less mere chance that we happen to be around at a time when Saturn has prominent rings and Mars has none. That said, Saturn does have unusually bright and extensive rings, which is because they’re made of ice and reflect sunlight well. Incidentally, I’m going to mention this here although it really belongs on homeedandherbs, my home education and herbalism blog: herbs are traditionally categorised into different planetary governances and zodiacal signs according to their features, so for example plants who vigorously defend themselves with spines or stings are governed by Mars. Plants with prominent rings are governed by Saturn, which seems to make sense until you realise that they were in fact already considered Saturn’s before Galileo discovered them in 1610.

Two rival theories about ring formation have been offered in the past. On the one hand, they could result from bodies which are torn apart because they entered the Roche Limit of the planet concerned, which at the time was Saturn because no other planetary rings were known to exist at the time. On the other, it could simply be that planets gather planetesimals (small chunks of potential future planets and moons) around themselves early in the history of star systems which fail to coalesce because of these tidal forces. This second theory probably isn’t correct as an explanation of the rings which currently exist, but it may nonetheless have been true in the early Solar System. Perhaps all the planets originally had rings, including Earth.

The transient nature of ring systems has another consequence: Jupiter may have had more obvious rings in the past or acquire them in the future. Moreover, these rings could be made of ice and brighter than Saturn’s because they would both be closer and reflect more powerful sunlight. A substantial Jovian ring system would have a diameter of 341 160 kilometres, considerably larger than Saturn’s 270 000 kilometre system, and at closest approach would be about half the distance to Saturn, making them reflect 60% more sunlight, be twice as large and therefore four times as bright anyway, which is over six times brighter. However, unlike Saturn, Jupiter’s axis is almost perpendicular to its orbit and we would only see them side-on. They would be detectable but not spectacular from Earth, although they would be large enough to be visible to the naked eye as a separate structure from the disc of the planet. Moreover, this may well have been the case in the past because Jupiter is close to the asteroid belt and many of its moons do in fact appear to be captured asteroids, and since it’s the largest known solar planet it stands the best chance of developing a substantial ring system, and in fact has done so. In a way, we are living at a slightly anomalous time in Solar System history because only the second largest planet has the most vivid rings.

The development of rings at this stage in the history of the system is most likely to be caused by planets capturing substantial bodies within their Roche Limits which do not immediately impact on their surfaces. The probability of this happening, assuming an even distribution of asteroids and the like, which is of course not so, increases with the size of the planet. Saturn has relatively weak gravity due to its low density, which is less than that of water, but the radius of its Roche Limit is large, so it’s relatively likely to acquire rings even though it doesn’t have much oompf. The Roche Limit is also a volume – effectively a hollow sphere with a planet at the centre – so the relative probability of rings can be calculated as the cube of the radius of the Roche Limit relative to another planet. This means that Saturn is about 760 times more likely to get rings over the same period of time than Earth, but also that Jupiter is 73% more likely to get them even if it occupied Saturn’s orbit rather than sitting next to the asteroids. It’s actually a bit of a freak occurrence that Jupiter’s rings are so much fainter than Saturn’s.

Our home world is the largest planet in the inner Solar System and all other things being equal is therefore the most likely planet of the four to develop rings. Venus is also quite likely, which would lead to a fairly spectacular view even from here, mainly in the form of a brighter Venus. All ring systems are likely to be similar in several ways. They will be the same relative width compared to the disc of the body at their centre, they will have gaps in them corresponding to the distances of large satellites, they will be circular and they will encircle the equator. They would, however, differ in other ways. The four gas giants are cold and therefore likely to have icy rings. Inner planets could also have this for a short period of time if they capture an icy body descending from the outer system, but this will be very temporary, only lasting a few decades at most in Earth’s case. They are more likely to have fairly dark rings made primarily of rock, carbon or iron, or a mixture. However, this doesn’t mean that the picture at the top of this post is unrealistic because although Cynthia is fairly dark, the surface still reflects enough sunlight to be clearly visible during the day and very bright at night. The rings would also be much closer and larger than our satellite, and therefore much brighter.

Earth’s rings could be seen as a kind of compensation for not having auroræ. The view near the Equator would be magnificent, and they would continue to be visible as one moved towards the poles, then as they disappear below the horizon, the auroræ hove into view. A ringed Earth would have a beautiful sky from everywhere.

Before considering the possibilities of how it might happen, it’s worth taking a break to smell the flowers at this point and have a go at imagining the situation of our own planet having rings in detail. From the equator, the rings would be invisible. Planetary rings are extremely thin. For example, Saturn’s are only ten metres thick. In order to get a good view, we would have to be away from the Equator, and with increased latitude two things would happen. The full width of the rings would become more evident and the rings would approach the horizon. The best view would be in places like Aotearoa/New Zealand, Argentina, Chile, the Mediterranean and the northern states of the US and southern Canada, which are all around halfway between the Equator and the poles. It would be a bit like having a permanent rainbow in the sky, although a less colourful one oriented east-west rather than somewhere near north-south, and quite a bit larger. Near the poles they would be very close to or below the horizon. There might also be a division in them, like the Encke and Cassini Divisions of Saturn’s. These are caused when particles orbit in resonance with a large moon. There would be a radius within the rings which would orbit ten times a month, and it’s possible that this would at least be sparser than the rest, but the resonance is quite far from the simpler, larger fractions involved which lead to Jupiter causing the Kirkwood Gaps in the asteroid belt or Mimas, the Death Star moon, causing the Cassini Division. Even these are less visible close up, so we would probably end up with a single solid-looking ring in our sky, although since it was so close we’d probably see something like the “record grooves” appearance Saturn’s have when seen from nearby, and there might also be “spokes” moving through them as they do with those. These spokes might be caused by lightning storms in Saturn’s atmosphere or meteorite impacts on the rings, causing static charge to repel some of the particles and make them slightly wider at those locations.

It would have various consequences. They would cast very large shadows corresponding to the seasons. There would be none at the equinoctes and they would be biggest near the winter solstice in the appropriate hemisphere. These would also be colder than the surroundings and there would therefore be winds blowing into them, and in certain places the shadows would be present intermittently for months at a time, notably in the mid-latitudes where the climate would usually be warmer. This would reduce photosynthesis, although since they would also be very bright there would be some compensation and this could also ameliorate the cooling effect. They would also occupy the position used on the equator by communications satellites. However, they wouldn’t impede space travel since this can occur away from the Equator.

That, then, is Earth with rings. It seems to be compatible with life but it would have significant effects on our climate, and there could also be a steady rain of meteors into the atmosphere at the equator, though these would mainly vaporise. This in itself might lead to more metal ions in the upper atmosphere, and I’m wondering if this would influence the auroræ and attract them towards the poles, making them brighter and more colourful.

Now the question is, has this or will this ever happen without human intervention?

When Earth first formed, it very probably did have rings like all the other planets, as the planetesimals orbited prior to colliding with the gradually accreting protoplanet. Slightly later on, the Mars-sized planet Theia collided with us, breaking off the outer layers of the planet and forming Cynthia. This too would have shown up as a ring, a very substantial one in fact. Saturn’s rings has a mass of less than half that of Mimas. Earth’s at this point would have had more than one percent of our own mass, which is many thousands of times greater on a planet whose mass is only one percent of Saturn’s. This is another illustration of how out of proportion our satellite is.

There is no evidence in favour of this next bit, but also nothing to rule it out and it’s entirely compatible with established facts about the history of this planet and the Solar System.

A large asteroid collides with this planet every few million years, including, of course, the Chicxulub Impactor which wiped out the non-avian dinosaurs. The Śiva Hypothesis holds that this planet moves through a galactic arm every 27 million years, causing an increase in impact events, although there isn’t a huge amount of supporting evidence for this. There was a period during which the Chicxulub Impact worked so well as an explanation for the extinction of the dinosaurs that cosmic impacts were evoked to explain all six prehistoric mass extinctions, the current one being excluded for obvious reasons, but there are various other events which could also explain them quite well. There are therefore sometimes direct hits by large bodies on this planet. How often does this planet encounter another body without an immediate collision? How often does it get within the Roche Limit, almost striking a glancing blow, and instead of hitting us is ripped apart by tidal forces and forms a ring? I don’t think anything at all rules this out, and in fact I think it must have happened a number of times in our history.

Looking specifically at the Chicxulub Impact, a ten kilometre wide object clearly did hit the future Gulf of Mexico 66 million years ago. However, how do we know that wasn’t simply the biggest or most unfortunate remnant of a larger body which had been orbiting the planet for some time previously? It may have broken up within the Roche Limit and given the planet rings, and also, less controversially, some of the rocks smashed up into space by the impact would have created rings. Maybe Palæocene Earth did have rings after all, and maybe they took millions of years to break up.

I can’t prove any of this of course, and in fact I can’t even think of how someone would go about testing this hypothesis. Even so, I would say that the balance of probabilities strongly supports the idea that this planet does sometimes acquire rings. It’s the largest inner planet, it has associated asteroids and for every impact there are countless near-misses. I think we used to have rings, have probably had them several times, and will one day acquire them again. As to when, who knows?

Bolivia

I have technically owned land in Bolivia. I don’t know if I still do because of the changes the country has undergone since I bought it. It was part of a scheme to prevent the building of a bridge which has now been built, but endangered the way of life of a particular indigenous people and the ecology of a rainforest area. The total amount of land was bought by a pressure group and divided up into small parcels which were bought by people all over the world to make it harder for the development company to trace the ownership. It’s very small, at about 13.4 ares.

Bolivia itself is an interesting country. It has the world’s highest capital, includes some of the world’s driest desert and the largest salt flat, and is the only majority Native American country, the rest of the population being White or Mestizo (mixed-race). It’s also landlocked since it lost its Litoral province. The above flag is called the Wiphala, and mainly represents the non-European contingent of the country’s population, i.e. most of them. The native groups include the Guaraní, Aymara and Quechua, with 6.5 million, 1.7 million and ten million respectively, though not all in Bolivia, which has a total population of eleven and a half million. It’s also the second poorest country in Latin America (insofar as it is Latin America that is) in spite of being unusually rich in mineral resources. My main association with Bolivia is miners dying young from lung diseases. Of course, Bolivia is not unusual in being a poor country with good mineral resources. The Congo comes to mind here in particular.

Probably the thing people most think about Bolivia is that it has the world’s highest capital. This is in fact not strictly true, for two reasons. Firstly, it actually has two capitals. The highest is La Paz, also known as Chuqi Yapu Marka, four kilometres above sea level. However, there’s also the constitutional capital Sucre or Suqri, where the judiciary as opposed to the seat of government is based. Secondly, Lhasa is also very high, but since Tibet is disputed and occupied by China, it may not count, although that’s a political decision. La Paz is so high that the boiling point of water there is 88°C and plasma televisions don’t work. The latter is because there is an argon gas filled gap in plasma TVs which expands at higher altitudes, making it harder for the signal to get across, although I understand that it just makes a buzzing noise. To be honest I think plasma TVs are a huge waste of money anyway and don’t live up to their reputation, but this post is not about display technology. The low oxygen in the atmosphere means that people living in La Paz have more red blood corpuscles per unit volume than most other people, which enables them to survive healthily most of the time but also increases the viscosity of their blood and therefore also the risk of heart and lung disease.

One of the distinctive things about Bolivia is the rural women’s national dress, which involves bowler hats and multiple skirts. Some women actually wrestle while wearing these, and their opponents may even include men. The bowler hats are worn by the Aymara and indicate that the women wearing them are married. They have a strong work ethic which includes the women and they tend to keep businesses within the family, so they have large families. The bowler hat tradition dates to the mid-nineteenth century, when Mancunian bowler hats were exported to South America for British men to wear, but they turned out to be too small so they were marketed to women instead. They’re also alleged to boost fertility and tend to be very expensive – hundreds of pounds. The skirts are partly that way because the climate is cold, so they need to be multiple and ankle-length, and they can be up to eight metres long. Culturally, calves are also considered sexually attractive so they tend to be hidden. The Aymara are notable for sticking with traditional dress rather than becoming Europeanised, unless you count the hats.

The Aymara and Quechua (Runa Simi being the official name) languages are similar but may not be closely related. There is a hypothesis that the thinness of the atmosphere leads to there being only three vowels, /a/, /I/ and /u/, because they sound more distinctive, although their pronunciation varies according to where they are in the word. Both changed their spelling conventions in 1975 and 1985, and I’m used to the older orthography, which was based on Spanish, so I find them a little hard to read at times. There also used to be a Tiwanaku Empire before the arrival of the Europeans, where both Aymara and Runa Simi were spoken, so they may have extensively borrowed vocabulary from a third source. They both have aspirated and ejective consonants, which combined with the three-vowel system makes them a little like Semitic languages in sound, but grammatically they are similar to Turkish, with separate suffixes for each grammatical idea, an inflectional case system, lack of gender, evidentiality and SOV word order. I mention this because there are so many unrelated languages which have these features, which suggests to me that there is some kind of human, or perhaps logical, default grammar which our spoken languages are likely to have. This also lends weight to the idea that the two languages are not closely related but are partly coincidentally similar, simply because they both represent a common type of language. Both languages share official status with Spanish in Bolivia.

Lake Titicaca is the world’s highest navigable lake at 3.8 kilometres above sea level and shared with Peru. Since Bolivia is landlocked, its navy is also found on this lake along with some of the rivers in the country. There are forty-one islands on the lake, some of which are inhabited. There are also large rafts, populated by native Americans who escaped from the Incas by moving onto the lake, which have schools, post offices and churchs on them. The total area is over 8 000 kilometres. It’s the remnant of a larger prehistoric inland sea although it’s now freshwater. There are aquatic species unique to the lake including the Titicaca water frog, who is up to sixty centimetres in length and a kilo in mass, and a flightless species of grebe. Titicaca is in an endorheic basin – no water flows out of the basin. Elsewhere, there are also pink river dolphins, also known as boto, living in the Amazon, who are the largest of all freshwater dolphins at over two metres long, and like many freshwater dolphins has poor eyesight due to the murky water selecting echolocation over that sense, and also has the most varies diet of all whales, comprising over fifty species of fish and freshwater crabs.

14 December 2007
Source
Own work
Author
Martin St-Amant

Salar de Uyumi is the world’s largest salt flat with an area of over ten thousand square kilometres. This is of course only a tiny fraction of the 2.5 million square kilometres of what is currently the Med, but was once and one day will again be a giant salt flat. As for Uyumi itself, one of its distinctive features is that it has a hotel built entirely out of blocks of salt, including the furniture, which because of the rainy season and the salt corroding the wiring, has to be almost completely rebuilt every year. Uyumi also turns into a mirror surface under the right rainfall conditions because it’s so flat, and it’s difficult to judge distances for the same reason – no visual cues. There’s also a train graveyard there and the surface is used to calibrate satellites in orbit because it’s so flat.

And it probably goes without saying that the Atacama Desert is partly in Bolivia, in the southwest of the country, although it’s mainly in Chile and Peru, Bolivia only including its eastern edge. This is the driest area on the planet, even drier than the Antarctic, which is mainly desert. Rainfall can be as low as one millimetre a year in some parts. It’s also considered to be one of the areas on this planet most like Mars, and attempts to replicate the Viking lander experiments there came up negative for life, by contrast with the real Martian experiments, one of which was positive. It’s also used as a filming location for programmes and films set on Mars. It used to be used for mining saltpetre and nitrate and was populated back into soon after the last ice age, by the Chinchorro Culture. It also contains the largest drawing of a human in the world, the Atacama Giant, which is in the same style as the Nazca carvings and was used to point to the position of our moonrise at a particular time of year. Besides humans, the desert is by no means lifeless, but the plants subsist on fog rather than rain. The desert is so dry because of a permanent temperature inversion created by a long-lived anticyclone over the Pacific and the Humboldt Current. If that sounds vague, it’s because I don’t understand it either.

Bolivia is of course named after Simón Bolívar, a Venezuelan general who led Bolivia and five other countries to independence from Spain in the early nineteenth century. The republic of Bolivia was created on 6th August 1825, and is one of the few countries named after a person, although there’s quite a glut of these in Central and Southern America such as Nicaragua and Colombia. Before the Spanish arrived, Bolivia was the location of Tiwanaku, a settlement which existed well before the Common Era and has a famous Gate of the Sun:

This civilisation was mysterious for a very long time, but apparently it became something like an empire and collapsed about a millennium ago. They had ceramics, sculpture, architecture and farming, but don’t seem to be as well-known as the Incas.

In the southwest of Bolivia and across the continent into Paraguay live the Guaraní, whose language is with Spanish official in that country. The Bolivian representatives are somewhat different from those elsewhere, partly because their history involved resisting the Inca Empire. I don’t know much about them except that they have nasal harmony in their language, which means that if a nasal consonant or vowel occurs in a word, it nasalises the entire word. Also, like German, Danish, Hebrew and Arabic, every word which might be considered as beginning with a vowel actually begins with a glottal stop. Unlike German, glottal stops are also fully-fledged speech sounds which can occur in other parts of words.

You might have noticed that I haven’t talked much about the politics of Bolivia here. This is because not only do I not know much about it, although their alliance with Cuba and Venezuela suggests they have socialist tendencies, but also I go on about politics a lot on here and thought you might need a break.

I haven’t mentioned Coca yet. Only two percent of Bolivian land is under cultivation yet it provides a quarter of the income for the country. It’s high in cash crops, but most notably coca is grown here, i.e. the source of cocaine. I have chewed coca leaves but not taken cocaine. It has a certain appeal, but it was a very long time ago. It’s used in highland areas such as La Paz to cope with the lack of oxygen. There is a related plant in Central Afrika which as far as I know has no psychoactive action, but the family is quite small. A coca leaf looks almost like what you’d draw if someone asked you what a leaf looked like. Because it’s used as a cash crop even where it’s illegal, it has major consequences for the situations in such countries as Bolivia and Colombia. Oddly, cocaine has been found in the hair of Egyptian mummies even though there is no other source than coca and its relatives. So has nicotine, but that’s more widespread. This fact has been used to suggest a connection between Egypt and the New World. However, it’s also possible that there were cocaine-rich plants native to Afrika which have since become extinct, and cocaine has also been found in the hair of ancient non-Egyptian mummies further south in Afrika.

There are a couple of opportunities for “compare and contrast” here. One is the difference between South and North America in colonial and post-colonial terms. South American countries fought for independence a few decades after the North American colonies and at no point did they unify in the way Canada and the US have, although Brazil is of course one of the largest countries. The Native American population in South America is proportionately higher than in North America, and they have a more prominent position in the national lives of their countries. The other is to compare South America and Afrika. When I was training, I think I perceived a significant difference between Afrikan and South American parasites which might in fact be quite dubious. It seemed to me that Afrikan parasites, while not exactly being a wonderful addition to one’s body, had co-evolved with humans, whereas South American parasites were still taking advantage of a relatively new species on the continent and had therefore not yet adjusted to not killing the host as often. That said, I can’t now remember how I got that impression. South America is more linguistically homogenous in terms of imperialist languages, which consist of Spanish, Portuguese, French, English and Dutch. There is a theory that Afrikan geography prevented the formation of large empires because it didn’t have large strips of similar biomes, unlike Asia, but it isn’t clear whether this is an imperialist excuse. The Inca empire did spread in a mainly linear way though. Afrika also has the Sahara.

I get the impression that Bolivia is essentially remote. It is partly an Andean republic and in a sense consists of the parts of South America which were relatively inaccessible from without. As such it has something of the character of other mountainous territories such as Wales, Tibet and Switzerland. However, in spite of the fact that I’ve owned land over there, I’m afraid that I’m most unlikely ever to visit this fascinating country, and all of this description has been from an utterly foreign person living in Northwest Europe who has never left that region.