by Alex Boese
An even more radical proposal was that the force of gravity might be declining throughout the entire universe. If this were so, it would cause the Earth’s mantle to weigh progressively less, which would reduce the compressive forces on the core and thereby allow it to expand, like a spring returning to its previous size. This idea was the brainchild of the German physicist Pascual Jordan, who in turn had adapted it from the speculative musings of the British physicist Paul Dirac, who had suggested that the physical constants of the universe (all those numbers that are never observed to change, such as the speed of light, the mass of a proton and the force of gravity relative to mass and distance) might vary over time. Since physicists don’t know why any of these constants have the values they do, it seemed vaguely plausible that some of them, such as the force of gravity, might change as the cosmos aged.
But a significant faction within the expansionist movement acknowledged that there really wasn’t any obvious mechanism of growth, and they argued that this shouldn’t be held against the hypothesis. After all, in science, the observation that something is happening often precedes the knowledge of why it’s happening. Darwin described the process of evolution by natural selection long before biologists uncovered the genetic mechanism that allows it to occur. Perhaps, in the future, physicists would discover a mechanism that caused Earth expansion, but for now it was enough to note that it was happening, even if no one knew why.
This was the situation in the late 1950s. Continental drift and Earth expansion both offered rival explanations of why the continents seemed to fit together, but neither one seemed inherently more plausible than the other. Both demanded the acceptance of some highly counter-intuitive notions, and, as far as most geologists were concerned, both were equally absurd because the continents simply didn’t move at all.
Then geological dogma was entirely upended. The cause of this dramatic turn of events was the discovery of sea-floor spreading. Sonar mapping of the ocean floor during the 1950s and ’60s gradually began to reveal the existence of gigantic underwater rift valleys that ran throughout the oceans of the world. In these valleys, the sea floor was literally splitting apart and spreading outwards on either side, causing the formation of new oceanic crust where magma bubbled up in the ever-widening gap.
This was an astounding discovery. The rift valleys were massive as well as being highly dynamic geological features. It took only a few years for geologists to realize that the conventional wisdom of fixed continents had been shattered. The land masses obviously had to move. But the question was, which explanation of continental movement was most compatible with this new discovery: drift or expansion?
A number of leading scientists, such as Bruce Heezen, who had conducted much of the sea-floor mapping, thought it was expansion. After all, the expanding-Earth hypothesis had predicted the existence of tension cracks in the ocean floor where new oceanic crust would be produced. So, for a brief historical moment, it seemed as if expansionism had a real chance of achieving mainstream acceptance.
But it didn’t last for long. Geologists soon realized that, not only was new crust being created in the rift valleys, but old crust was simultaneously being destroyed at subduction zones, located along the edges of the continents where the ocean floor plunged beneath the land. By 1970, this had led to the development of plate tectonics, which envisioned the creation and destruction of the ocean floor acting as a kind of conveyor belt that moved the continents endlessly around the globe. In this model, the continents didn’t drift so much as float on top of the convection currents within the mantle.
This wasn’t exactly like continental drift, but it was close enough to essentially vindicate Wegener. It was a derivation of his theory that emerged out of the discovery of sea-floor spreading as the new geological orthodoxy. The expanding Earth, on the other hand, still had no mechanism. Nor could its advocates explain the existence of subduction. So, after its brief flirtation with mainstream acceptance, its scientific status plummeted down like a rock.
That might seem like it should have been the end of the story of the expanding-Earth hypothesis. In hindsight, its advocates had correctly identified the fit of the continents as an important phenomenon, they’d just chosen the wrong explanation for it. Wegener had won the debate, not them. So, surely, the hypothesis would quickly fade away. Geologists certainly hoped that would happen.
But it didn’t. Instead, the expanding-Earth hypothesis entered a new, altogether stranger phase of its career. Far from disappearing, it stubbornly hung around to become the great contrarian hypothesis of geology. Its advocates continued to meet up at conventions, they submitted articles to academic journals and, with the emergence of the Internet in the 1990s, they held court online to an apparently large and appreciative audience. All of which frustrated mainstream geologists no end.
It’s worth noting that its supporters weren’t an entirely homogeneous group; there was a spectrum of belief among them. On one end were the fast expansionists who argued that the Earth was growing at a rapid rate, well over five millimetres a year, and that most of this growth had occurred in the past 200 million years. The leading proponent of this view was the geologist James Maxlow, a student of S. Warren Carey, who predicted that, in another 500 million years, the Earth will have swelled into a gas giant the size of Jupiter.
At the other end of the range were the slow expansionists, who harkened back to the work of László Egyed. They argued that the Earth had been growing almost imperceptibly over its entire history, by mere fractions of a millimetre every year. The fast expansionists attracted the majority of the public attention because of their more extravagant claims, but, as far as most geologists were concerned, the whole bunch of them were equally crazy because there was simply no credible explanation for why the Earth would expand.
Given this, why did support for the hypothesis endure? One of the core issues motivating its advocates was their continuing conviction that the continents fitted better on a smaller globe. They returned to this subject obsessively, insisting that this superior fit shouldn’t be possible by mere chance.
The most rigorous advancement of this argument was made by Hugh Owen, a palaeontologist at the British Museum. In 1984, Cambridge University Press published his Atlas of Continental Displacement. This consisted of an exhaustive cartographic tracking of what he maintained was the progressively better fit of the continents on a smaller Earth. The best fit of all, he concluded, was on an Earth 80 per cent its current size. Even mainstream reviewers, such as the British geologist Anthony Hallam, grudgingly acknowledged it was a work of serious, if eccentric, scholarship.
Perhaps the primary reason for the persistence of the hypothesis, however, was because all the evidence for or against it was somewhat indirect. The debate circled endlessly around questions such as the fit of the continents or possible mechanisms of expansion. What it didn’t address was whether the Earth was actually measurably changing in size. This was because scientists couldn’t put a tape measure around the planet to find this out, and the inability to do this created just enough doubt to allow the expansionists to continue to press their case.
At least, scientists couldn’t do this until the twenty-first century, when satellite-based technology did actually make it possible. The expansion of the Earth could be put to direct empirical test, and a team of NASA researchers set out to do this.
Even with the advanced technology, it was a challenging task given that the Earth isn’t a static entity. Sea levels and land masses are constantly in motion, rising and falling due to mountain formation and other natural processes, all of which had to be taken into account. But, in 2011, after a ten-year period of observation, the team reported their results: there was no evidence that the Earth was expanding. It appeared to be fixed at its current size. NASA issued a press release to spread the news, triumphantly declaring, in so many words, that the expansionist heresy could finally be put to rest.
And that, one might think, was that. Once again, it
seemed the story of the expanding Earth had reached an end.
Or maybe not. Its supporters have proven to be quite persistent.
In 2016, expansion advocate Matthew Edwards published an article in the peer-reviewed journal History of Geo- and Space Sciences in which he acknowledged that the satellite measurements were indeed a problem for proponents of fast expansion. Rapid growth should definitely have been detected. But slow expansion of the type imagined by László Egyed, he argued, was a different story, particularly if one looked more closely at the results of the NASA study.
As it turned out, the researchers hadn’t actually found no expansion at all. They had recorded expansion of 0.1 millimetres a year, possibly as high as 0.2 millimetres due to the inherent uncertainty of the measurement techniques. They deemed this to be ‘not statistically different from zero’. But Edwards countered that it was absolutely different from zero, because even an expansion of 0.1 or 0.2 millimetres a year, over 4.5 billion years, becomes quite significant. And more recent measurements from Chinese researchers at Wuhan University had suggested that the expansion rate might be nudged up as high as 0.4 millimetres a year, which put it well within the range predicted by slow expansionists.
Had the expansionists snatched victory from the jaws of defeat? Edwards conceded that more study is required. One problem is that the vast majority of ground-based stations the satellites relied on to make measurements were located in the northern hemisphere. Perhaps future research, looking more evenly at the surface of the entire planet, will conclude definitively that no growth is occurring. But, even so, he insisted, it might be premature to close the case entirely on Earth expansion. A variety of it could yet be vindicated.
CHAPTER THREE
It’s Alive!
As we approached the solar system, we noticed that the Earth differed dramatically in appearance from its planetary neighbours, hanging in space like a brilliant blue-green marble. The liquid water that covers much of its surface is the primary cause of this distinctiveness, responsible for the blue colour, but it’s the presence of life that adds the tantalizing hint of green, and it is life which will be our focus in this section.
But what do we actually mean by ‘life’? Scientists have struggled to answer this seemingly simple question. They’ve identified various properties that living things seem to uniquely possess, such as that they’re highly organized, grow, reproduce, metabolize energy, respond to stimuli and evolve. But not everything we would identify as living possesses all these properties. Sterile animals can’t reproduce, but they’re nevertheless alive. And, more problematically, things we would assume to be non-living share many of these traits as well. Both crystals and fire, for example, can grow and reproduce. As a result of these ambiguities, researchers haven’t been able to agree on a single definition of life. Many argue that it’s a mistake to even assume there is a clear-cut division between life and non-life.
Returning to the view of our planet, other mysteries about life present themselves, such as how it began and why the Earth appears to be its only home. Trying to solve these puzzles by looking back in time to when the Earth first formed only raises more questions. Scientists date the formation of the Earth to approximately 4.54 billion years ago, and, relatively soon after that, around 3.7 billion years ago, we can see that living organisms were present in the primeval oceans. That’s the enigma. Based on the evidence left behind, it’s not at all clear how the life forms got there.
You might assume that it would primarily be biologists who ponder these issues of life’s nature and origin. But, actually, interest in them is highly interdisciplinary, attracting the attention of cosmologists, astronomers, philosophers, physicists, geologists and even sanitation engineers. And there is very little scientific consensus about the answers. Some speculations are considered to be more plausible than others, but there are many that roam much further afield.
What if everything is conscious?
How can a bunch of inanimate matter transform into a living organism? That’s the big question posed by the origin of life. Inanimate matter just sits there until external forces prompt it to move, whereas living organisms, even the simplest of them, possess agency. They do things. They metabolize nutrients, respond to stimuli, grow, reproduce and evolve. The gulf between life and non-life seems almost unbridgeable. But what if the central premise of this mystery, as framed by science, isn’t quite right, because what if matter, in its fundamental state, isn’t entirely inanimate? What if it possesses some qualities usually attributed only to living things? In particular, what if it possesses a rudimentary consciousness – an awareness of some kind that it exists?
This is the odd claim of the theory of panpsychism. Its advocates argue that absolutely everything in the universe is conscious. This includes people, dogs, plants, rocks, plastic bags, car tyres, iron nuggets, puddles of water and even electrons. To be clear, the theory doesn’t claim that everything is conscious in the same way. The ability of an electron to experience or feel would obviously be very different, and far more primitive, than that of a human. Nor does the theory claim that everything has the power to reason. It doesn’t imagine that rocks and car tyres are sitting around contemplating philosophy. Nevertheless, panpsychism does insist that all matter, at some level, has the capacity to experience its existence.
The name of the theory comes from the Greek words pan (all) and psyche (mind), and, while the concept may sound suspiciously like New Age mumbo jumbo, it’s actually been around in Western culture for millennia and has, in the past century, attracted some prestigious supporters, including the physicist Sir Arthur Eddington and the philosopher Bertrand Russell. Most recently, the philosophers David Chalmers and Philip Goff have championed it.
When people first hear or read about panpsychism, their initial reaction is typically to dismiss it as absurd. This is the hurdle the theory always has to overcome, because it just seems so blindingly obvious that everything can’t be conscious. Is anyone supposed to seriously believe that spoons and floor tiles are sentient? The possibility scarcely seems worth debating. It’s self-evidently ridiculous.
But defenders of the theory point out that, paradoxical as it might seem, for most of history, going all the way back to prehistoric times, panpsychism has been widely regarded as the common-sense point of view to take. The assumption that non-biological matter lacks consciousness actually represents a new, peculiarly modern way of looking at the world.
For example, animism is a form of panpsychism. This is the belief that every aspect of the natural world – the sun, wind, water, rocks and trees – is animated by its own spirit. Anthropologists suspect that this was a universal feature of the earliest forms of religion practised by hunter-gatherer societies.
Animist assumptions continued to appear in the thoughts of the earliest Greek philosophers, such as Thales of Miletus and Pythagoras, who all took panpsychism for granted. In the fourth century BC, these ideas became enshrined in the writings of Aristotle, whose work served as the basis for the Western understanding of the natural world for the next 2,000 years.
In his work, Aristotle explained the behaviour of non-living things by assuming that they exhibited some of the qualities of living things. Specifically, a sense of purpose and therefore a primitive form of consciousness. According to him, everything had a proper place or ‘final cause’ that it strived to achieve. For example, fire and air floated upwards, he said, because these elements naturally belonged in the sky, and so they strived to attain their correct location. An inner will propelled them. Likewise, earth and water belonged at the centre of the world, and so they strived to move downward.
Historians of science note that, in this way, Aristotle’s universe was fundamentally biological. He used the properties of life, such as purpose and will, to explain the behaviour of non-life. Everything in Aristotle’s universe, including astronomy and chemistry, ultimately reduced to biology. But, around the seventeenth century, a new philosophical world view calle
d mechanism emerged, which insisted that everything, in its fundamental state, consisted of inert matter entirely lacking a sense of inner purpose. Everything, in this way of thinking, ultimately reduced to physics. Even biological organisms were reimagined as being like complicated machines.
Why this new world view emerged at that particular time, in the particular place it did (Europe), is a matter of debate. One theory is that it might have had something to do with the invention of weight-driven mechanical clocks. By the middle of the fourteenth century, such clocks had been installed in the central squares of most major cities. On the outside they appeared animated, but everyone knew that on the inside they were just a bunch of inanimate metal cogs and gears. So, they offered a kind of ready-made metaphor for how nature might operate. They demonstrated how lifeless matter, arranged in the right way, might give the appearance of being alive. By the seventeenth century, it had become popular to compare nature to a clock and to describe God as a watchmaker.
Whatever may have been the reason for the emergence of this new mechanistic world view – and it doubtless involved more than just clocks – it turned the premise of Aristotle’s ancient science on its head. The universe was now assumed to be made up of ‘dead’ particles, entirely lacking any kind of animating spirit and set in motion by mechanical forces (like the weights that made the gears of a clock move). As the eighteenth-century philosopher Immanuel Kant put it, ‘lifelessness, inertia, constitutes the essential character of matter.’ This was the great change in perspective that ushered in the rise of modern science.