History of the British Climate Part I

Yesterday I covered the last 400 000 years of British climatological history. Today I’m going to do something like the previous æon, and possibly all the way back to the beginning of the world. In fact, yeah I’ll do that.

4 543 million years ago, the future Solar System was a swirling disc of dust and gas orbiting a newborn Sun. Jupiter had already formed and was gradually pulling the particles whose times to orbit were in harmony with its own slightly towards itself, leading to them drifting slightly out of phase with it and clumping into fairly insubstantial rings of matter. I’m not sure how warm the belt which would become us was at the time, but it was probably well below freezing point, because if it hadn’t been, there would have been no grains of water ice. On the other hand, there were also comets, so maybe not, but the fact remains that the Sun was dimmer and weaker back then and there were no greenhouse gases in a position to warm the dust and gas which would become Earth. It took seventy to a hundred million years for it to form, and at the beginning it would’ve been slightly more massive, have no permanent moon and the atmosphere would have been briefly high in hydrogen and helium. Within ten million years of its formation, a Mars-sized body which has been christened Theia hit us and shattered the outside layers of the planet, causing them to go into orbit around us and fall together into the body I call Cynthia and most other English speakers call “the Moon”. Clearly there was no such place as Britain at this point and the entire surface of the planet was molten rock heated by the mechanical energy of compression and collision along with radioactivity. The atmosphere would have been substantially superheated steam. Shortly after being hit by a planet-sized body, the atmosphere would in fact have been vaporised rock. It’s possible to determine the climate of the entire planet at this point, as it was quite uniform, meaning that although it makes no sense to talk of Britain, it does make sense to describe how conditions were everywhere. This eon lasted about 500 million years, and during this period the vaporised rock atmosphere would have condensed and fallen onto the surface as drops of lava. Towards the end of the Hadean, life was present, which seems to imply that there was liquid water in at least some places.

The next period is referred to as the Eoarchean, when the pressure was probably dozens of times higher than it is today, more like the solid surface of Venus than today’s Earth. Temperatures were between 0 and 40°C and there may have been ice ages. To quote ELO, “the weather’s fine but there may be a meteor shower”, because this was the time of the Late Heavy Bombardment, when for 300 million years asteroid collisions and other large meteors would have rained very often from the sky, although this has recently been questioned. The atmosphere was high in methane and carbon dioxide, which being greenhouse gases may have ensured that this planet was warm enough for life to survive on it given that the sun was 30% weaker than it is now.

All of this is rather vague and applies to the whole world. The earliest known British rocks are found in Na h-Eileanan Siar, also known as the Western Isles, and have been dated at 3 000 million years old. It isn’t clear that anywhere can be meaningfully called Britain before that date, and there’s no trace of anything else. It was likely to have been a small piece of the surface of the planet with unclear neighbours. The rock concerned is gneiss, which is a common component of continental shields, which are bits of Earth’s surface that haven’t been affected much by continental drift, such as mountain formation or rifting. It would be a bit excessive to call the rocks in Na h-Eileanan “continental shield” because they’re quite small, the nearest substantial example of one being most of Finland and Sweden, but they are the original and only rocks in that small area of these isles.

Even long after this, the island of Great Britain would have been in several parts, making it difficult to describe the nature of its climate. It means imposing the current situation on the past when it’s actually quite transient on a geological time scale. Also, in some areas, including this one, Charnwood, sedimentary rocks were laid down at the bottom of the sea or ocean and the idea of this being Britain is almost meaningless. It also changes the significance of climate, and as far as being at the bottom of a really deep ocean is concerned, almost irrelevant.

In the Archean, which lasted fifteen hundred million years, the planet was shrouded in methane clouds and there was practically no free oxygen in the atmosphere. The sedimentary rocks surviving which had been exposed to the atmosphere show no glacial erosion, but they do show evidence of rivers and rain. Therefore it did rain. In fact, presumably there was an enormous rainstorm lasting thousands of years at some point in the late Hadean when the oceans were formed due to the atmosphere and surface getting cool enough for the steam to condense out and persist on the surface, but because the pressure was much higher this would have happened long before the surface temperature dropped below 100°C. It is actually possible to measure the surface temperature by looking at the proportion of oxygen-18 in the rocks. There are two stable isotopes of oxygen: 16 and 18. Because oxygen-18 is heavier, molecules containing it vaporise at a slightly higher temperature. Chert, which is a sedimentary flint-like rock, is silica, i.e. silicon dioxide, containing oxygen, and is present in some Archean deposits, making it possible to measure the temperature where it was laid down. This puts the ocean temperature at 70°C, but this is probably wrong because weathering once it was exposed to the atmosphere would influence this. The degree of weathering which occurred was unaffected by land plants, since there weren’t any – there weren’t any plants in fact – and suggests a surface temperature between 18 and 24°C, so semitropical. The fact that there was neither excessive heat nor excessive cold suggests various things about the planet such as the ratio of methane and carbon dioxide, a relatively transparent atmosphere and only limited land surface, so it seems that not only do we only have bits of Na h-Eileanan available but that may have been partly because there just wasn’t that much land.

The Archean was followed by the Proterozoic, which began around 2 500 million years ago. This was characterised by the evolution of blue-green algæ, which proceeded to release oxygen into the atmosphere and removed carbon dioxide. This may also have reduced the activity of methane-producing organisms, another greenhouse gas, and also oxidised the methane. Incidentally, this hedging language I’m using here is down to my ignorance more than scientists’. Anyway, the consequences of this were that iron began to rust in the ocean, depositing itself in bands of rust on the sea bed, and the temperature of the planet fell, triggering an ice age. It’s theorised that this planet has two relatively stable states climatically, which it switches between: icehouse and hothouse. Icehouse has generally not dominated but can do at certain times and in fact it is at the moment, anthropogenic climate change notwithstanding. The dominant state is hothouse, which is generally warmer than today for millions of years at a stretch. Even so, there does seem to have been an ice age in the early Proterozoic, and at the end of the Proterozoic there was another much more severe one. In between those times the world-wide climate would’ve been warmer than today.

The Cryogenian Period was a crucial time in our planet’s history. It appears that the land was mainly equatorial at the start of this period, which would probably have included the bits of land which were to become these isles. We were situated just south of the Equator, in Laurentia and Baltica, as part of the supercontinent Rodinia, meaning a hot, wet climate, except that we were below sea level, so a very wet climate! The oddity about this time is that glaciers are found at the Equator, i.e. the parts of the supercontinent which were equatorial at the time, and it’s thought that this means that most or all of the planet was covered in ice and as cold as Antarctica. My comment about tropical conditions applies to how things were before this arose. There are a couple of hypotheses about how this happened. One is that Earth may have had an axial tilt as high as 60°, meaning that constant night in the winter and the midnight Sun in the summer would’ve applied to everywhere further from the Equator than today’s Brazil or Israel. Very surprisingly, a snowball Earth can only happen if there’s a lot of equatorial land. Most of the Sun’s heat is absorbed near the Equator, meaning that if there’s a lot of land there the heat would not be absorbed as much, and this would cool down the whole planet.

By Ryan Somma – Life in the Ediacaran SeaUploaded by FunkMonk, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=24277381

The Ediacaran follows the Cryogenian and is for this part of Britain very significant, because it’s from this time, lasting 94 million years from 635 to 541 million years ago, that some of the most famous fossils found in this area date. These can be seen in a local museum and include the feather-like Charnia as seen above, and Bradgatia linfordensis, a lettuce-like organism obviously (to locals) named after Bradgate Park and Newtown Linford, both in Charnwood. Charnodiscus concentricus is another. These are all thought to be “quilted” animals who left no descendants, although some people class them in their own kingdom because they’re quite unlike any animals or plants we’re familiar with. They appeared 600 million years ago and all died out before the Cambrian. They may have had symbiotic algæ in their compartments, meaning that since many of them were also attached to the sea bed, the water must have been sufficiently shallow to allow light to penetrate. Hence Charnwood was still underwater, but the ice must’ve been gone and the water wasn’t particularly deep.

Rodinia was breaking up at this time, so there would’ve been a network of shallow seas, which sounds like the situation as it was here. Rodinia was an unusual supercontinent because it seems to have formed by the landmasses moving all the way round the world and colliding with each other on the opposite side to where they originated, which meant they had a long time to erode and the land surface was quite flat. The network of seas would have increased rainfall on the land, since much more of it would’ve been closer to the sea. This may in fact have been part of what triggered the earlier ice age. The temperature of the Ediacaran was still around 2°C cooler than the average for the Holocene, so it looks like the weather here would’ve been cold, wet and rainy. Plus ça change!

The Cambrian was warmer, around 8°C warmer than the Holocene average, and in fact this set a precedent for the generally warmer temperatures of the Phanerozoic, our current eon. During the next period, the Ordivician, sea levels rose by a hardly believable six hundred metres. This ended as a new supercontinent, Gondwana, reached the South Pole and a new ice age started, lasting twenty million years. A gamma ray burst may then have cause the mass extinction at the end of the period, meaning that it may have rained concentrated nitric acid.

Around 400 million years ago, three mini-continents collided to form the British Isles as we know them today, and it begins to become more meaningful to talk about British climate. These were Laurentia, which is effectively all of Scotland, Avalonia, which is England and Wales, and Armorica, which is Brittany, Devon and Cornwall plus a lot of other land such as Iberia. Glen Mòr, the fault along which Loch Ness is situated, continues into Ireland and therefore I imagine Ireland was also in two halves before this. Avalonia began as a volcanic island chain north of Gondwana. Britain was about 30° south of the Equator then. It drifted gradually north, crossing the Equator about 300 million years ago, and over this time other land collided with the forming Pangæa, meaning that it was increasingly far from the sea. This is about the time the Carboniferous started and the future Britain became covered in the rainforests which would become the coal measures, so Britain was hot and swampy, and the oxygen content of the air was so high that lightning strikes would have ignited wet vegetation, so there would be many forest fires even though conditions were damp. Around 305 million years ago, climate got cooler and drier and sea level fell, leading to retreat of coal forests from higher ground and the emergence of fragmented rain forests, which were no longer able to maintain their genetic diversity and there was a lot of inbreeding, shrinking of the size of, for example, horsetails, to cope with the conditions and a new ice age started in the Southern Hemisphere, although not severe enough to make Britain cold.

By this time, Pangæa was forming, as were the Pennines. Hot dry desert conditions took over from rainforest, with presumably an intermediate phase which today would be like the Serengeti, although with very different flora and fauna the details are not obvious. The late Permian was a peculiar time climatically, as the interior of Pangæa seemed to have extreme temperature variations so that it was both very hot and very cold at different times of year, and it’s been suggested that this was a cause of the Great Dying, where almost all life on Earth became extinct. Britain was now in the northern tropics, and as such was in the same zone as the Sahara is now. The Scottish Highlands at the time would’ve been as high as the Himalayas and formed part of a range which extended southwest into the Little Atlas and Appalachians. There might also have been a rain shadow desert to the east, making it even drier than it would’ve been without them, but the monsoon conditions which prevailed to the southeast might make it heavily forested.

In the Triassic there were salt flats in Cheshire, hence the salt mines which existed there in historical times, and red sandstone forming in what is now the Southwest, hence the very red soils in that area. Towards the end of the Triassic, the sea level began to rise again, converting much of the isles into a subtropical shallow sea and many of the hills and mountains as they existed then into islands, such as the Mendips.

The following photo is taken from this website and will be removed on request:

This is the “Barrow Kipper”, or rather a monument to where it was found in 1851. Barrow-upon-Soar is about an hour’s walk from where I’m sitting and between 200 and 150 million years ago was underwater, over the entire Jurassic Period. This particular plesiosaur was formerly classed as a Rhomaleousaurus but now as an Atychodracon, from the Early Jurassic, looking something like this but with a bigger head:

It used to be thought that plesiosaurs had to climb ashore to lay their eggs, so this suggests that there was land nearby, but fossils have since been found of pregnant ones, and their limbs were arranged in such a way that they would’ve had to have dragged themselves along the shore quite roughly. However, although it isn’t from precisely the same time, a few miles away in Rutland, the largest and most complete dinosaur fossil ever found in Britain was unearthed, a Cetiosaurus, like a mini-“Brontosaurus”, suggesting that this area was an archipelago of smaller islands or just near a beach. There is a famous traditional song called ‘Ashby De La Zouch By The Sea’, which has often made me wonder whether that particular nearby Leicestershire village ever was.

I am of course a Southerner, and as such Leicestershire will always be slightly foreign to me. My mother is from Maidstone, a place sufficiently famous for its Iguanodon finding that the animal is actually on their coat of arms:

These dinosaurs, dating from 157 million years ago, are also found, along with very many others, on the Isle Of Wight. It’s tempting to telescope all these findings into an imaginary scenario where they’re all simultaneous just because they’re all Jurassic, but in reality the Jurassic Period lasted fifty-six million years, almost as long as the time since the non-avian dinosaurs became extinct, and the Isle Of Wight dinosaurs are mainly early Cretaceous. There were, however, coral reefs in Yorkshire. In the Cretaceous, the situation was once again one of rising sea level with lagoons and streams. To the extent that these isles existed at that point, they were substantially united. That is, Ireland and Great Britain formed a single island, which was intermittently joined to the mainland and still steadily drifting north.

The Late Cretaceous climate was warmer than today’s at the same latitude, which was about the same as Madrid and Rome, although it had been cooling for millions of years. When the Chicxulub Impactor hit, the widespread fires would have raised carbon dioxide levels tenfold and caused a greenhouse effect heating the planet by 7.5°C. In the Palæocene the climate was slightly cooler and drier due to dust in the atmosphere reflecting heat into space, but tropical forests then developed all over the world, even in the Arctic, where the water was lukewarm. The Eocene would’ve involved warm swamps in many parts of Britain.

At this point I’ll repeat something I said a few days ago about Europe. Europe over the Cenozoic, that is, since the extinction of the non-avian dinosaurs, has been gradually transitioning from an archipelago to a large peninsula, and the scattered islands of the region have shown a trend of joining together to build a subcontinent, for want of a better word. Looking at Great Britain and Ireland in this way, they are late developers, or outliers which show how the rest of the region used to be. There’s a common, and correct, idea that before the end of the last Ice Age and for several thousand years after that, Ireland and Great Britain formed a peninsula, and this is true, but there has been a kind of seesawing appearance and disappearance of sea around us and the level of the land at the moment has been pushed down by the recent weight of ice and is gradually springing back up. Hence it does make sense to speak of the British Isles, or perhaps an island comprising Ireland and Great Britain plus low-lying land in between, in the earlier Cenozoic, and moreover to see them as the westernmost members of a collection of islands a bit like the Caribbean or Indonesia in arrangement, although that may be a bit of an exaggeration. The North European Plain, though, was underwater for quite some time, Iberia ceased to be an island around the start of the Cenozoic and the Italian-Illyrian region was also separate for a long interval.

In the Neogene, Britain arrived in its present position and is no longer drifting north. Hence the climate began to approach how it is today although it would’ve been somewhat warmer still. Finally, the Pliocene saw a general drying out and the Pleistocene brings me to the start of yesterday’s post.

I can’t completely guarantee that all of this is accurate as I know a little, but some of it is disputed and I’m probably in the Dunning-Kruger trough at this point where I haven’t reached the point of realising how little I really know and how wrong I’m actually being. Nonetheless, it’s nice to imagine how our climate could’ve been more Mediterranean or Caribbean in particular in the geological past, and also, wouldn’t it be nice to holiday at home but do it using a time machine so we could get to the really sunny and warm climates which this part of the world, so to speak, used to experience?

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?

Dinosaurs In The Bible

There’s more than one way to believe there are dinosaurs in the Bible: the fundamentalist way and the other way. In fact the other way is two other ways, but it’s more fun to look at the fundamentalist way first. One of the non-fundamentalist views is a bit idiosyncratic, but I’ll leave that until last. Also, I’m going to talk about archosaurs as a whole rather than just dinosaurs, although in the end it makes little practical difference.

I’ve just Googled “Jesus riding on a dinosaur”, expecting to find just a couple or even one picture repeated all over the web. In fact I found this, which leaves me with the bizarre task of sorting through their intellectual property licences. Therefore what I’m going to do is post this picture with the offer to take it down if anyone wants:

From here.

This is not yer classic dinosaur Jesus picture of course, but it’s sweeter than the other one. Also, this is a very inaccurate picture becuase neither Jesus nor dinosaurs looked like that. The more usual picture, which I won’t post here so as to avoid increasing the risk of getting into hot water, is of Jesus riding a dinosaur.

Creationists fall into at least two categories regarding dinosaurs, and when I say creationists, I’m not just talking about Christians but also a few observant Jews, quite a few Muslims, and oddly a few people whose religious beliefs are not Abrahamic. It has to be said that the stereotype of a Christian being creationist is not true. In fact the Roman Catholic Church, which is widely regarded as Christian except by some Protestants, dogmatically accepts evolution, as do almost all Jewish believers. There are a few rabbis who do reject evolution. In the ’90s, a dairy company was refused Kosher certification because it had giant Mesozoic dinosaurs on a milk carton, which a particular rabbi said contradicted the account in Genesis, and this illustrates one view: that non-avian dinosaurs never existed because the Universe is only a few thousand years old. In Judaism this is very much a minority view. Islam is another matter entirely. A number of Islamic majority countries are also majority creationist, and at least one such country has prohibited the teaching of evolution as fact in state schools. However, it’s notable that even creationist Muslims don’t always feel particularly strongly about creationism and the subject simply doesn’t come up much in school curricula. That is, it’s sometimes mentioned but isn’t necessarily considered a massive issue. Christian creationism, particularly among Protestants, is another matter entirely, and once again there is a division between Christian creationists who believe in “dinosaurs” and those who don’t.

There is a problem with not believing in fossils, particularly if, as was sometimes the case in the past, one believes Satan put them there. This is that various masses of rocks and minerals are made of fossils, such as coal, oil, natural gas, chalk and flint. If you assert that the Devil created them, you’re then stuck with the implication that he created much of this planet’s surface, unless you also believe Earth is not a planet, but it’s still a problem. This is close to the heresy of Gnosticism. Even so, there is a fundamentalist Protestant conspiracy theory based on the idea that dinosaurs are fake, which amounts to this. Dinosaurs are seen as “nature red in tooth and claw”, which emphasises the idea of life being about struggle and fighting rather than love, and are of course also charismatic, particularly for younger children. This is a kind of hook to capture children into an atheistic, anti-Christian world view which eventually leads them to deny the existence of God and the saving power of Christ. However, even among creationists this seems to be a minority view.

Within creationism, there are two subdivisions, one much odder than the other. The straightforward school is of course Young Earth Creationism, which cites various pieces of evidence to demonstrate that it must only be a few millennia since the Cosmos was created. These include the shallowness of dust found by Apollo astronauts, the presence of recently solidified lava which tests as being millions of years old even shortly after it’s formed, the number of comets, the shape of galaxies (which is an odd one because they’re millions of light years away and therefore must have existed a very long time ago), the existence of two types of Cepheid variables which can be easily mistaken and so forth. There’s also a general principle that entropy refutes evolution, which does not, however, work for reasons I can’t be bothered to go into right now but is covered here. This view does at least have the merit of linking evolution with a young Earth, which in the end is necessary because six thousand years is nowhere near long enough for many evolutionary processes to have become apparent. But the really weird one is Old Earth Creationism. This accepts that the planet is æons old but rejects the reality of evolution. It seeks to reconcile Genesis with “Day-Age Creationism”, which asserts that the six days of creation are in fact whole geological periods lasting millions of years, and in doing so creates a major problem for itself: how is it that mutations haven’t accumulated over that period and caused major changes in forms of life?

Both forms of Christian creationism emphasise the importance of Noah’s Flood. For instance, they may claim that the reason giant fossils of dinosaurs are further down in the strata than smaller fossils of other organisms is that being heavy, they sank to the bottom whereas lighter species stayed further up. As far as I can tell, creationists seem to believe that biodiversity was greater before the Flood than afterwards, and tend to believe that the Flood wiped out the dinosaurs. This is problematic from the perspective of Noah’s task to rescue all species of animal from the catastrophe. Some Christian creationists also believe that there are still Mesozoic megafauna around in tiny populations scattered around the globe (I’m assuming none of these people are flat Earthers here). Therefore, the question then arises of Scriptural evidence for the presence of dinosaurs. It would be odd, some people claim, if there were giant reptiles around at the time who were not mentioned at all in the Bible given that it does mention all sorts of other animals.

Some Christian Young Earth Creationists have attempted to resolve this issue by asserting that the Behemoth and the Leviathan are both examples of giant dinosaurs. The Behemoth seems to be a hippopotamus. Blake drew them thus:

 Behold, Behemoth, which I made as I made you; he eats grass like an ox.

Behold, his strength in his loins, and his power in the muscles of his belly.

He makes his tail stiff like a cedar; the sinews of his thighs are knit together.

His bones are tubes of bronze, his limbs like bars of iron.

He is the first of the works of God; let him who made him bring near his sword!

For the mountains yield food for him where all the wild beasts play.

Under the lotus plants he lies, in the shelter of the reeds and in the marsh.

For his shade the lotus trees cover him; the willows of the brook surround him.

Behold, if the river is turbulent he is not frightened; he is confident though Jordan rushes against his mouth.

Can one take him by his eyes, or pierce his nose with a snare?

Job 40:15-24

To me, this sounds very much like a hippo apart from the description of the tail, which is hard to account for unless it’s a composite animal of some kind like the Greek Chimæra. The Leviathan sounds more like a whale and is mentioned I think six times in the Tanakh and again in the Apocrypha. It may be a sea serpent, but it’s also been claimed to be a crocodile. A notable description is in the verses immediately following the above passage:


Can you lead Leviathan[a] about with a hook,
    or tie down his tongue with a rope?
 Can you put a ring into his nose,
    or pierce through his cheek with a gaff?
Will he then plead with you, time after time,
    or address you with tender words?

 Will he make a covenant with you
    that you may have him as a slave forever?
 Can you play with him, as with a bird?
    Can you tie him up for your little girls?
Will the traders bargain for him?
    Will the merchants[b] divide him up?
 Can you fill his hide with barbs,
    or his head with fish spears?
 Once you but lay a hand upon him,
    no need to recall any other conflict!

Unlike the Behemoth, the Leviathan is never very clearly described, and some have taken from this the idea that the animal being described is familiar. If it is actually a crocodile, this is a description of an archosaur.

Archosaurs are a clade including crocodiles, alligators, caimans and birds. In days of yore they also included non-avian dinosaurs, whom are difficult to refer, and pterosaurs (more loosely referred to as “pterodactyls”). If this is true, it is in fact quite close to being a reference to a dinosaur as we would classically understand them. Creationists sometimes make a lot of this and use Behemoth and Leviathan as proof that giant dinosaurs were around in Biblical times. Due to the depiction of all animals other than humans as herbivorous soon after creation, many YECs claim that Tyrannosaurus rex and his kin were all herbivorous. They also sometimes claim that they were on the Ark, perhaps as young adults. Since there are seven hundred known species of this kind of dinosaur, this is still quite hard to imagine.

Another animal sometimes compared to a dinosaur by modern creationists is the dragon. Chapter fourteen of the Book Of Daniel, not generally considered canonical and present only as apocrypha in the Septuagint (the Greek translation of the Tanakh) is referred to as ‘Bel And The Dragon’. Daniel undertakes to kill a dragon without using a sword and feeds the animal cakes made of tar, hair and barley which cause the dragon to burst. This is somewhat similar to the creation myth of the Babylonians, but there may be no link. In the New Testament, the Book of Revelation mentions dragons several times, although most people see the work as largely symbolic so this may not be particularly useful to creationists.

There have actually been creationist expeditions to find archosaurs considered widely to be long extinct, such as pterosaurs in Papua (it’s not technically correct but I’m just going to call them pterodactyls here). It’s also been suggested that scientists have hushed up the existence of pterodactyls, but this would be irrational because their existence doesn’t threaten the idea of an old Earth at all. There are birds, such as herons and frigate birds, who do look like pterodactyls in silhouette or at a distance. Hoax photographs are also quite easy to produce because there are pterodactyl kites and remote control planes made to look like them too. This whole subject is remarkably close to that of UFOs, and in fact there’s a sense in which apparent surviving pterodactyls are literally UFOs – Unidentified Flying Objects. There’s also the Mokele-mbembe, who is a cryptid said to live in the Congo area resembling a sauropod. The odd thing about these is that they were described as like sauropods (the long-necked herbivores such as Diplodocus) by people who knew nothing about prehistoric life. Although it’s generally believed that it isn’t a dinosaur, it may be a memory passed down of a species of amphibious rhinoceros. Amphibious rhinos and rhino-like animals did exist once, although apparently they didn’t overlap with humans. Once again, these would not be a threat to the idea of an old Earth, but there is nonetheless a major problem with the idea of what are widely considered to be Mesozoic megafauna surviving the Chicxulub Impact.

I’ve mentioned Nessie before on here. The problem with a pliosaur surviving the Maastrichtian-Danian mass extinction is that if large reptiles survived at all, they would have come to dominate the planet again and become widespread, as their niches would be vacant, so there would either be plenty of Cenozoic fossils of non-crocodilian and non-avian archosaurs and giant reptiles which went into decline or they’d still be around today in large numbers, and they clearly aren’t. The Eocene was in fact probably even more suitable for these kinds of animals than the Cretaceous had been, and in fact the idea that the Mesozoic was the Age of Dinosaurs and the Cenozoic the Age of Mammals is an over-simplification. There were fairly large mammals around in the Mesozoic and very large reptiles and, yes, dinosaurs, in the Cenozoic. And the fact that I’ve finally used the word “dinosaur” here is probably misleading, and leads me to my second, rather technical point: dinosaurs really are mentioned in the Bible!

Birds are of course dinosaurs, and birds are mentioned repeatedly in both the Tanakh and the New Testament. This sounds at first like a bit of an arsy point, but birds and “dinosaurs” have turned out to be a lot more similar to each other than previously thought, in particular because of their feathers, although not all of the large dinosaurs did have feathers. At least two dozen species of bird are mentioned, substantially in the Kosher/Treyf list. Regarding basal birds, that is, those most closely related to dinosaurs as we generally think of them, ostriches, peacocks, quail and waterfowl are all mentioned. Notably, the ostrich is mentioned in Job chapter 39, just before the Behemoth and Leviathan references:

“The wings of the ostrich flap joyfully,
    though they cannot compare
    with the wings and feathers of the stork.
She lays her eggs on the ground
    and lets them warm in the sand,
unmindful that a foot may crush them,
    that some wild animal may trample them.
She treats her young harshly, as if they were not hers;
    she cares not that her labor was in vain,
for God did not endow her with wisdom
    or give her a share of good sense.
Yet when she spreads her feathers to run,
    she laughs at horse and rider.”

Job 39:14-18

This may in fact be the closest thing to a description of a “real” dinosaur in the Tanakh or the New Testament. It brings Gigantoraptor to mind.

There’s also the question of whether ideas of dragons and other mythical beasts derive from fossil remains of dinosaurs. For instance, it may be that griffins are in fact Protoceratops fossils, with the neck shields interpreted as wings. They’re said to be referred to in Psalm 50:11 –

I know the birds of the mountains,

the creatures of the fields are subject to me.

In Hebrew, this is:

יָ֭דַעְתִּי כָּל־עֹ֣וף הָרִ֑ים וְזִ֥יז דַ֗י עִמָּדִֽי׃

The antepenultimate word in that, translated as “the creatures” could be literally translated as “and the griffins” – “wa-ziz”. Technically this could mean dinosaurs are referenced twice in that verse. A “ziz” is a giant bird whose wings can blot out the Sun. They are in a sense the aerial counterparts to Leviathan, kings of the birds in the same way as Leviathan is king of the fish. Here is a non-Biblical account of the Ziz:

As Leviathan is the king of fishes, so the Ziz is appointed to rule over the birds. His name comes from the variety of tastes his flesh has; it tastes like this, zeh, and like that, zeh. The Ziz is as monstrous of size as Leviathan himself. His ankles rest on the earth, and his head reaches to the very sky.

It once happened that travelers on a vessel noticed a bird. As he stood in the water, it merely covered his feet, and his head knocked against the sky. The onlookers thought the water could not have any depth at that point, and they prepared to take a bath there. A heavenly voice warned them: “Alight not here! Once a carpenter’s axe slipped from his hand at this spot, and it took it seven years to touch bottom.” The bird the travelers saw was none other than the Ziz. His wings are so huge that unfurled they darken the sun. They protect the earth against the storms of the south; without their aid the earth would not be able to resist the winds blowing thence. Once an egg of the Ziz fell to the ground and broke. The fluid from it flooded sixty cities, and the shock crushed three hundred cedars. Fortunately such accidents do not occur frequently. As a rule the bird lets her eggs slide gently into her nest. This one mishap was because the egg was rotten, and the bird cast it away carelessly.

The Ziz has another name, Renanin, because he is the celestial singer. On account of his relation to the heavenly regions he is also called Sekwi, the seer, and, besides, he is called “son of the nest,” because his fledgling birds break away from the shell without being hatched by the mother bird; they spring directly from the nest, as it were. Like Leviathan, so Ziz is a delicacy to be served to the pious at the end of time, to compensate them for the privations which abstaining from the unclean fowls imposed upon them. […] The creation of the fifth day, the animal world, rules over the celestial spheres. Witness the Ziz, which can darken the sun with its pinions.

This is from Midrash Aggadah, which is the non-legal elaboration of themes in the Tanakh. As usual, this could get complicated, but so far as I can tell there seems to be an association between the Ziz and the phoenix, which would of course be another mythical dinosaur.

As well as leaving their traces in the rocks to be intepreted as dragons and griffins by humans, it seems reasonable to suppose that dinosaurs may be vaguely fossilised in the human psyche itself. At the time of their demise, many dinosaurs would’ve towered over our ancestors. This animal, Purgatorius:

(c) Patrick Lynch

is close to our lineage and lived around the time of the Chicxulub Impact. They were about fifteen centimetres long and weighed less than forty grammes, and like other early primates were native to North America, which is whence we came. It’s easy to imagine those ears having to adapt to the sounds of heavy dinosaurs pushing their way through their native forests, crushing everything before them or simply predating them, and for that adaptation to induce an instinctive fear of large, rumbling, slavering monsters with big teeth such as now populate our mythology and horror fiction. And also the Bible. Therefore, maybe there is indeed a sense in which Behemoth, Leviathan and Ziz are indeed dinosaurs, remembered in our genes for survival’s sake. This is the other way dinosaurs appear in the Bible, and it raises the question of what else instinctive has led to Biblical text, and beyond that, whether that is in fact the hand of God writing it in.