The Expanding Earth Theory

Some time ago, I had a Peters Projection map of the world from ‘New Internationalist’ magazine. The idea behind the Gall-Peters Projection (it wasn’t originally Peters) is that it’s supposed to show all the land in correct proportion as to its size, which I presume it does, but the problem is that it doesn’t preserve compass direction and considerably distorts the shapes. As far as I can work out, it’s a cylindrical projection that differs from Mercator by progressively reducing the north-south lengths to zero as they approach the poles. There is a lot to be written about this map projection in particular and political correctness, but not here.

No, where I’m going with this is the reaction one of my friends had to the maps of continental drift in the book. There were a couple of pages showing the evolution of this planet’s appearance from the supercontinent Pangæa in the late Permian to its current appearance. Pangæa looked roughly like this:

There are certain issues with this map, such as the fact that Antarctica is ice-covered in it, which it wasn’t at the time, but it succeeds in roughly illustrating the supercontinent and the condition of the surrounding tectonic plates at that time. Again, Pangæa and the general idea of supercontinents is interesting but still not quite what I’m going to talk about today.

My friend made a rather disparaging comment regarding the map of Pangæa along the lines of it just being guesswork and “how the hell could they know this is what happened?” I explained to him about the continents fitting together, the presence of symmetrical bands of magnetic minerals on the floor of the Atlantic, the continuation of coal seams across continents which match the jigsaw and the presence of fossils of the same species in widely separated parts of the world. Incidentally, today I might add that Earth’s interior has now been found to be cooling faster on one side than the other, indicating that something large was blocking the heat for a long time in the distant past, and this is thought to be the above supercontinent. His response, after I’d said all this, was “yeah, but how the hell could they know this is what happened?”! It was like I hadn’t said anything!

To some extent, I think his attitude is a healthy one, and I presume it was based in distrust for authority of any kind. He’s an intelligent, well-educated guy and I’m not disparaging him for his opinion. It’s just that I feel that it illustrates something which I doubtless also do, where I reject counter-intuitive and novel ideas, sometimes just because they’re new. It’s a widespread phenomenon for people to receive a new idea, perhaps not listen very closely to the evidence cited in support of it and proceed to pick holes in it and reject it out of hand. This is all the more so when immediate observation seems to contradict it, as can be seen today with Flat Earthers. They have an approach they describe as “Zetetic Cosmology”, which is the idea that one should always depend on what can be directly observed oneself, and in many ways this is commendable, and like my friend involves distrust of authority, which is again to be encouraged. However, there comes a point when one either has to trust experts in a field other than one’s own or find an example of something which would prove one’s assumption wrong if it turned out to be true when tested. In the case of the Flat Earth, my answer is to use railway timetables in distant parts of the world and online traffic cams to observe daylight, because in both cases these being fake would involve a ridiculously vast conspiracy, lots of people missing important appointments and a whole load of RTCs. Other examples of this would include the idea that the Apollo missions were a hoax and the various Covid-19 conspiracy theories.

At the same time, it’s uncomfortable to have one’s world view challenged on the other side. I don’t know how far back my acceptance of continental drift goes, but I remember mentioning a piece of evidence for it in school in 1976, which is currently forty-five years ago when I was nine, so it’s one of those things which forms a kind of cherished part of the jigsaw I use to make sense of life, and it’s disturbing to have that questioned. Consequently, although I’m aware of lots of evidence supporting it, I probably use that evidence more as a comfort blanket to confirm that my beliefs about the world are correct rather than actually enquiring into it in any great depth. That does also mean I trust experts in this area. But there’s a psychological urge to force people into believing what I believe which is more about competition and perhaps aggression than altruism, and that’s not a good motive.

Alfred Wegener was an early proponent of the theory of continental drift. He noted that South America and Afrika seemed to fit into each other neatly, with Brazil jutting out in a shape very close to how the Gulf of Guinea “juts in”, and the Great Australian Bight matching the coastline of Victoria Land in Antarctica. He thought of this in around 1911.

Prior to this, and in fact for many decades after, the prevailing wisdom was that land bridges rose and sank between the different continents, causing flora and fauna to mix, which is for example why the continent of Lemuria in the Indian Ocean was posited. There are prosimians (non-simian primates such as tarsiers and bush babies) in Madagascar, continental Afrika and Indonesia, so how did they get to be in such widely separated places? The answer was supposed to be Lemuria, named after lemurs. Oddly, although this idea has now been discarded, there was in fact formerly a fairly large landmass in the Indian Ocean and in a few million years time there will be again, when the Afrikan Rift Valley opens up and East Afrika splits off. The descriptions of changes in geography in Olaf Stapledon’s ‘Last And First Men’ also relate land bridges rising and falling, as was generally believed in the 1930s. I even have a book from the late 1940s with a map of them as they were supposed to be in the Mesozoic, shown above.

Land bridges don’t really work though, because they violate the principle that crustal rocks generally float at the same level above the mantle depending on its depth and density. For land bridges to appear and disappear in that way, their density or thickness would have to change.

The problem with continental drift was that there didn’t seem to be a mechanism for them to move around. Wegener proposed something called Polflucht – “pole flight”. His idea was that the centrifugal effect of Earth’s rotation pulls the land masses away from the poles and causes them to break apart as they approach the equator. If this idea worked, it would make sense to a certain extent because we’re in a situation where the Tethys, an ocean which used to stretch all the way round the equator, has now closed due to the collision of Afrika and Eurasia and the formation of the Isthmus of Panama, and Australia has also moved north from its prior connection with Antarctica. The problem is, however, that the crust is far too sturdy to allow this to happen. It’s also interesting that Wegener, who was mainly an expert on polar geology, would focus on this aspect of the planet to explain.

At this time, as far as I can tell, there wasn’t any idea of a supercontinent cycle, where continents collide together and are broken up, only to join together again in a different configuration hundreds of millions of years later. The reason I say this is that the explanation which was proposed after this was rejected seems to suppose that Pangæa was the one and only original supercontinent which then broke up and the continents formed then drifted into their current positions. The idea proposed was of course the Expanding Earth Theory:

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The idea here is that all the land was joined together when Earth was first formed, and this planet was considerably smaller back then. Then Earth expanded and the single landmass cracked apart, creating today’s world map. There were various hypotheses about how this might have happened, one of which I find a lot more interesting than the others. One is that Earth started off as the rocky core of a gas giant like Jupiter and was therefore compressed and under a lot of pressure. The Sun gradually boiled off the atmosphere and as the pressure reduced, the planet “sprang out” and expanded due to its release. Another theory is based on the idea of the luminiferous æther, which in itself probably could do with an explanation. It used to be thought that just as sound or waves in water need a medium to carry them, so did light, radio waves and the like, and this was referred to as the æther. Although this idea is not completely dead for complicated reasons which slip my mind right now, the æther’s existence was refuted by the Michelson-Morley experiment, which showed that light travels at the same speed whether or not it’s moving in the direction of our planet’s orbit or at right angles to it, meaning that there was no static medium carrying it and ultimately ushering in Einsteins theory of relativity. Incidentally this experiment is also used by Flat Earthers to “prove” that Earth does not orbit the Sun or rotate. Isaac Newton believed that gravity was caused by a condensation of the æther combined with its rarefaction, which was eventually applied to the idea of the atmosphere doing the same thing, thereby providing the basic theory for powered heavier-than-air flight by explaining lift. Æther was later demonstrated to be necessarily incompressible and it was thought that matter was a sink in this æther, an idea which was clearly on its way to becoming Einsteins theory of general relativity and in fact something I used to believe myself up until I was about thirteen. This was then elaborated by Ivan Yarkovsky into the suggestion that Earth gradually accumulated matter from the transmutation of the æther into atomic matter and therfore slowly expanded.

Those are the less interesting explanations. The one which I feel drawn to, although it isn’t true, is Dirac’s. Paul Dirac was one of the most important physicists of the last century and is extremely respected. He proposed that the gravitational constant was slowly decreasing, causing the planet to expand gradually. Once again this explains continental drift, and seems to develop fairly naturally out of Newton’s and Yarkovsky’s theories of gravitation, but it also does something else which is very interesting. It amounts to an explanation for the expansion of space, and therefore is quite economical and elegant in its explanatory power. It isn’t just about Earth but the whole cosmos.

There is an odd parallel between the Expanding Earth Theory and theories of the evolution of the Universe. Over the past century there have basically been four of these. One of the best supported is now refuted, which is the Steady State Theory. This is the idea that space is infinite and constantly expanding, with matter being generated slowly within it, so that at any one time the visible part of the Universe looks roughly the same. In this view, there was no beginning to the Universe and it will always exist. The established and widely accepted theory today is more or less the Big Bang Theory, which is that the Universe expanded out from a single point around 13 800 million years ago and will continue to expand forever. I have my issues with this but I won’t mention them today. If there was only slightly more mass than there in fact seems to be in the Universe, it would also end up collapsing into a similar state to the early Universe in the distant future. Finally, there is the “oscillating Universe”. This involves an endless series of collapses and expansions, and raises the philosophical question of whether time is cyclical or each instance of the Universe is a new one. Although the Big Bang Theory is the only really acceptable one among scientists at the moment, there is also a theory that the Big Bang was preceded by a collapsing Universe made of antimatter when time was running backwards, which sounds pretty similar to the oscillating Universe to me.

Just as there was an oscillating Universe theory, later discredited, there was also an oscillating Earth theory. This involved the planet going through alternating phases of expansion and contraction which explained the phenomena on this planet which look like they’re caused by contraction. I imagine this includes mountain ranges but that’s just my guess. I find it interesting that there were two cyclical expansion-contraction theories about the world, one involving Earth and the other the Universe.

It is of course very appealing that there should be a single explanation combining continental drift and the Big Bang Theory based on weakening gravity. I don’t know if this has ever been done, but it also strikes me as a good explanation for the fact that fossils of extinct life forms tend to be much bigger than the life forms around today, such as dinosaurs and giant insects. Maybe this is because the fossils themselves have expanded over time and back in the day, the animals and plants who became them were of relatively modest size. However, this is not so because the Expanding Earth Theory is refuted, and in science you have to be brutal about your emotional attachments. Dirac’s idea is absolutely lovely, but it’s also dead wrong.

I mentioned train timetables earlier as a way to refute the Flat Earth hypothesis. This works because a sphere cannot be mapped onto a flat surface without distortion, as illustrated by Peters Projection. This means that two distant train routes of the same length would in some cases be distorted on a map. The Flat Earth is effectively a map of the real Earth, because it’s a curved surface forced into a flattened shape. This means that somewhere on this flat Earth, notably in Canada and Australia according to the main idea Flat Earthers have Earth’s shape, it ought to take a lot longer to go the distance the route is supposed to cover than it actually does. Now it could simply be that the map shown above is wrong, but there will always be routes whose length is dramatically distorted if Earth has a continuous flat surface and Euclidean geometry is roughly applicable, because every map distorts the planet’s surface. This is a particularly reliable reason for saying Earth cannot be flat.

As it happens, the same kind of idea can be applied to the Expanding Earth theory. I mentioned previously that there are stripes of magnetic minerals on the floor of the Atlantic. These are generated when the ocean floor spreads out from the central ridge, which is volcanic. As magnetic materials float in the lava, they get lined up with Earth’s magnetic field, which varies in its direction and strength. These then solidify with their alignments pointing in particular directions, and they line up symmetrically because the ocean is spreading from a ridge running roughly down the middle in both directions. If Earth was expanding, these magnetic materials would line up as if they’re on a smaller planet the older they are, meaning that it would be like attempting to project a globe onto a larger one without changing the sizes of the map. They would not line up according to longitude.

Satellites are now able to measure the size of the planet to within two hundred microns and there is no expansion faster than that. Continental drift is faster than that at about an inch a year in some places, so the idea that Earth is expanding is redundant, as it fails to explain what’s going on. The continents are also moving in different directions. For instance, the Pacific is gradually narrowing, as is the Mediterranean, so there isn’t a general trend towards expansion.

The trouble with this evidence is that it starts to become a little abstract and therefore lays itself open to being distrusted. As soon as it becomes difficult to follow a line of argument, or where it involves trusting an expert in a different discipline from one’s own experience, the possibility of error or perhaps conspiracy arises. This isn’t necessarily something to be distrusted, but at the same time questioning and distrust is important. The ultimate solution may be to become as well-informed as possible on certain matters, and perhaps to be self-aware when one is overly attached to a particular view, and maybe question one’s motives. Because whatever else is true, Dirac’s version of the expanding Earth and its link with an expanding Universe is truly appealing, but it’s still turned out to be wrong. But it’s tough to accept this.