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This is the Big Bang theory, which first took shape back in the 1920s, though it didn’t achieve widespread acceptance right away. For several decades during the mid-twentieth century, it faced a serious challenge from a theory called the steady-state model. This alternative cosmology, proposed in the late 1940s, made the case for a radically different creation scenario in which the universe had no beginning and the Big Bang never happened. In fact, steady-state advocates argued that a fundamental principle of science prohibited the Big Bang from ever having happened.
They didn’t propose, however, that this lack of a beginning meant that creation itself had never occurred. Just the opposite. They maintained – and this was the oddest part of the theory – that creation was going on all the time. They envisioned bits of matter continuously materializing out of the void in the far reaches of space. Exactly what form this new matter took wasn’t clear. The authors of the theory speculated that it was probably stray hydrogen atoms that popped into existence, though one of them whimsically suggested it might even be spontaneously emerging cakes of soap, but they contended that, whatever form the new matter took, the universe endlessly renewed itself by means of this process – a bit like, if it were possible, a person achieving immortality through a perpetual infusion of young, healthy cells.
Crack open any science textbook and it’s not going to say anything about stray atoms or cakes of soap popping into existence out of nothing. Modern science absolutely doesn’t believe such a phenomenon is possible. It would be more like magic. So, how did the authors of the steady-state theory convince themselves that this idea of continuous creation might be a reality? To understand this, let’s back up a bit and first examine the genesis of the Big Bang theory, because the one led to the other.
It was observational evidence that provided the inspiration for the Big Bang theory. During the 1920s, the astronomer Edwin Hubble, using the large new telescope that had recently been installed at the Mount Wilson Observatory in California, discovered that almost all the galaxies in the visible universe were rapidly receding from one another, as if fleeing outwards. This led him to conclude that the universe must be expanding.
This discovery, in turn, quickly led the Belgian physicist (and Roman Catholic priest) Georges Lemaître to reason that, if the universe is getting bigger, it must have been smaller in the past. Much smaller. If one were to reverse time back far enough, he surmised, one would eventually arrive at an initial moment when all the material in the universe was compressed together into a single small mass, which he called the ‘primeval atom’. Everything in existence, he argued, must have come from this one source. This logic was compelling enough to rapidly establish the Big Bang as the leading scientific theory about the origin of the cosmos.
The steady-state theory developed subsequently, but its inspiration came from more abstract, philosophical concerns. It was the brainchild of three Cambridge researchers: Hermann Bondi, Thomas Gold and Fred Hoyle. Bondi and Gold were both Austrian émigrés who had fled Nazi Germany, while Hoyle was a native of Yorkshire, in England. They met when the British army put their scientific talents to work researching radar during World War II, and they continued their friendship as young professors following the war.
All three agreed that Hubble’s discovery of the expansion of the universe was important, but they felt that Lemaître’s conclusion had to be incorrect because, they believed, it contradicted a fundamental principle of science – this being that the laws of nature are universal and apply uniformly everywhere and at all times. They insisted that this was an absolute concept which couldn’t be compromised. They warned that, if you started messing with it – if, for instance, you decided that the law of gravity worked on Tuesdays, but maybe not on Wednesdays – then the entire structure of science would collapse. Knowledge would become impossible.
This principle, as such, wasn’t controversial. They were right that it was a fundamental part of scientific belief. But, when they rigidly applied it to the question of the origin of the universe, it led them to the startling conclusion that the creation of matter and energy couldn’t have been a one-time event, as Lemaître assumed, because, if creation had been possible once (which it evidently had been, because we exist), then it must always be possible and always will be. Creation had to be an ongoing process. If the laws of nature are constant throughout time, how could it be otherwise?
They criticized Lemaître’s theory as being profoundly unscientific because it violated this principle, leaving creation unexplained as a mysterious, one-time event at the beginning of time. Bondi scolded, ‘To push the entire question of creation into the past is to restrict science to a discussion of what happened after creation while forbidding it to examine creation itself.’
This, in a nutshell, was the dispute between the two cosmological models. Big Bang advocates appealed to observational evidence that suggested a one-time creation event, whereas steady-state proponents, in response, invoked a philosophical principle to insist that creation had to be ongoing and continuous.
Bondi, Gold and Hoyle conceded that the idea of matter being continuously created would strike many as strange. After all, there were other scientific principles that needed to be considered, such as the law of conservation of energy. This states that energy can neither be created nor destroyed; it can only change form. Therefore, matter, being a form of energy, shouldn’t ever pop into existence out of nothing.
Just as importantly, there wasn’t a shred of observational evidence to support the claim of continuous creation. Scientists had never witnessed anything like such a phenomenon. The physicist Herbert Dingle angrily compared the concept to the alchemical belief that lead can be changed into gold by means of occult magic.
Nevertheless, the Cambridge trio still insisted that it was more reasonable to assume creation was an ongoing process rather than a one-time event. To support this contention, they carefully worked out the details of a cosmological model based upon never-ending creation to demonstrate how it could plausibly work. This led to their steady-state model.
The story goes that the three researchers initially came up with the grand vision of their alternative cosmology after watching a 1945 horror movie, titled Dead of Night, about a man trapped in a recurring nightmare. The movie ended with the man waking up once again at the beginning of his dream, and this looping narrative structure made the researchers think of a universe with no beginning or end. That connection probably wouldn’t seem obvious to most people, but the bottle of rum the three were sharing after the movie, as they sat in Bondi’s apartment, evidently helped the analogy make sense to them.
Whereas the Big Bang universe began with a violent, explosive event and then underwent dramatic change over time, their steady-state universe was all calmness and serenity. It offered the reassuring vision that, on a sufficiently large scale, the cosmos always has and always will appear the same.
In his 1950 textbook on cosmology, Bondi explained that the term ‘steady state’ was meant to evoke this idea of a universe that always maintains the same large-scale appearance. He compared it to a river. The water in a river constantly changes as it flows downstream, but the overall aspect of the river remains the same from one day to the next. The river maintains a steady rate of flow. Likewise, the steady-state universe would change on a small scale all the time, but its overall aspect remained forever the same.
Continuous creation was the key to maintaining this stability. If whatever existed was all that ever would, and no new matter ever came into being, then the universe would eventually fade into a cold death as stars burned through all the available fuel and went dark. But continuous creation provided a never-ending supply of fuel, allowing new stars to form even as old ones burned out.
By their calculations, it didn’t even require a lot of matter-creation to keep the universe running. The amount was so small that a person would never be able to see it happening, nor could any known experiment detect it. As Hoyle, who was known for his ho
mespun explanations, put it: ‘In a volume equal to a one-pint milk bottle about one atom is created in a thousand million years.’ It was also Hoyle who suggested, somewhat tongue-in-cheek, that the matter-creation might take the form of cakes of soap.
As for the law of conservation of energy that forbids the creation of new matter, Hoyle argued that it was actually possible for continuous creation to happen without violating this law. The trick that allowed it was negative energy. Hoyle hypothesized the existence of a universe-wide field of negative energy, which he called a ‘creation field’ or C-field. Any disturbance of this creation field, he said, would cause it to increase in size, which then triggered the creation of an equivalent amount of positive energy (aka matter). The simultaneous creation of positive and negative energy cancelled each other out, leaving the total sum of energy in the universe constant.
Critics dismissed this as a mathematical trick, but Hoyle responded that it nevertheless worked, because the law of conservation of energy only required that the total amount of energy remained the same. It didn’t matter how much positive and negative energy came into existence. As long as the sum total balanced out, the conservation law wasn’t violated.
The creation of matter also served a second purpose. As it formed, the creation field grew, and, because its energy was negative, it had an antigravity effect, causing the universe to expand. This fitted in with Hubble’s earlier observations. The expansion itself then acted as a kind of cosmic trash sweep. Old stars and galaxies were pushed outwards, past the edge of the observable universe, allowing new ones to take their place. In this way, all parts of the steady-state system worked together like a smoothly running piece of machinery, on and on for eternity, with no beginning and no end.
The Cambridge trio published the details of their new cosmology in 1948. It appeared as two articles: one authored by Bondi and Gold, and the second by Hoyle alone. They then set about promoting the theory. It’s one of the small quirks of history that, in the course of doing so, Hoyle accidentally gave the Big Bang its name. Until that time, Lemaître’s theory had usually been referred to as the ‘evolutionary cosmology’ model, but during a BBC radio lecture in 1949, Hoyle described it, somewhat dismissively, as the idea of matter being created ‘in one Big Bang at a particular time in the remote past’, and the phrase stuck.
For a while, the steady-state theory gained a modestly large following, especially among British researchers. Historians of science have noted that the theory, by keeping the entire cosmos nicely calm, steady and unchanging, seemed to appeal to the British love of stability and tradition. Hoyle was also a powerful and influential champion. In the mid-1950s, he led a team that worked out the physics of stellar nucleosynthesis – how elements such as carbon and iron are forged out of hydrogen and helium inside suns. This discovery is considered to be one of the greatest achievements in astrophysics of the twentieth century.
What eventually did the theory in, however, was observational evidence, which had always been the stronger suit of the Big Bang theory. As astronomers continued to explore the universe, they found that it simply didn’t look the way the steady-state model predicted it should.
During the 1950s, astronomers had begun using the new technology of radio telescopes to peer deep into the most distant, and therefore oldest, parts of the cosmos. What they found was that the galaxies in those regions were more densely packed together than they were in younger parts of the cosmos. This directly contradicted the steady-state prediction that the universe should always have had the same appearance (and therefore density) as it does now.
The real knockout blow, however, came in 1965 with the discovery of the cosmic microwave background. This is a faint whisper of electromagnetic radiation filling every corner of the universe. Big Bang theorists had predicted that exactly such a phenomenon should exist, left behind as a radiant afterglow of the extremely hot initial conditions of the early universe. Steady-state advocates, on the other hand, were caught flat-footed. They didn’t have a ready explanation for why this cosmic background radiation was there.
In the opinion of most scientists, these pieces of observational evidence, taken together, tipped the balance decisively in favour of the Big Bang theory. They clearly indicated that the universe must have had a beginning. As a result, the steady-state theory rapidly lost support and, by the 1970s, the Big Bang had gained acceptance as the standard model of cosmology.
Not to be beaten, in the 1990s Hoyle tried to cobble together a comeback for the steady-state theory. He partnered with the astrophysicists Jayant Narlikar and Geoffrey Burbidge, and together they devised what they called the quasi-steady-state cosmology.
In this new version, they conceded that observational evidence did indicate some kind of big, cosmic-scale event had occurred approximately fourteen billion years ago, but they argued that this event didn’t necessarily need to be the origin of the universe. They proposed, instead, that the universe went through endless fifty-billion-year cycles of contraction and expansion. They didn’t imagine that it contracted all the way down to the size of Lemaître’s primeval atom. During its most recent contraction, they said, it had remained large enough for entire galaxies to remain intact. This differentiated their idea from some models of the Big Bang that envision the universe going through cycles of collapse and rebirth. But it shrank enough, they claimed, that what appeared to be the Big Bang was actually the last contraction phase ending and the present expansion phase beginning. This allowed all the observations cited as evidence for the Big Bang to be reinterpreted within the framework of continuous creation.
To most astronomers, this new model seemed little more than a desperate attempt to save a failed theory, and they basically ignored it. It certainly did nothing to put a dent in the popularity of the Big Bang theory. Sadly, Hoyle died in 2001, and with his death the steady-state model lost its most vocal and prominent advocate.
Given this history, it would seem easy to dismiss the steady-state theory as an ambitious but misguided attempt to found a cosmological model upon a philosophical principle rather than observational evidence. Certainly, it must have been doomed to failure! But the thing is, the theory actually raised a legitimate question: how did the creation of matter and energy occur? How did something emerge out of nothing? If bits of matter randomly popping into existence throughout deep space is the wrong answer, then what is the right answer? What is the Big Bang explanation for the phenomenon?
Up until the 1970s, the prevailing school of thought among Big Bang advocates was simply to treat creation as an off-limits subject. The evidence strongly indicated that a single creation event had occurred, but there was no clue as to why it had happened or what caused it, so it seemed pointless to speculate about it. But when the Big Bang became enshrined as orthodoxy, ignoring the question of creation began to feel unsatisfactory. As the historian of science John Hands has said, it became like the elephant in the room of modern cosmology. A lot of scientists felt that some kind of explanation was necessary.
Of course, there was always the God solution. Perhaps a divine being had caused creation with a snap of its fingers. It didn’t escape the notice of opponents of the Big Bang that the theory seemed peculiarly compatible with this explanation. Nor did it escape the notice of Pope Pius XII, who, in 1951, praised the theory for offering scientific proof that the universe had a creator. Over the years, many of the staunchest Big Bang critics have been atheists who have accused it of being little more than a device to surreptitiously sneak theology into science. Lemaître, they point out, was both a physicist and a priest.
Big Bang advocates vehemently denied this charge, noting that many of them were atheists too! Anyway, they didn’t want a religious solution to the mystery of creation; they wanted a proper scientific one. But the problem they encountered, as they pondered how to explain creation within the context of the Big Bang, was that the critique by steady-state proponents was actually right. It was very odd that creation would only have happen
ed once. The fundamental forces of nature, such as gravity and electromagnetism, are all ongoing. They don’t turn on and off. So, why would some force have allowed creation to happen once, but then forbidden it from ever occurring again?
This was the puzzle, and logic led inescapably to one possible, though paradoxical, answer: if creation can’t occur in our universe, then it must have happened elsewhere. As bizarre as it might sound, there must be more to the cosmos than our universe, and creation must somehow have occurred (and possibly still is occurring) out of sight, in that other region.
This explanation required a redefinition of the term ‘universe’. Traditionally, the word had referred to absolutely everything in existence, but now it was given a more limited meaning. The term ‘cosmos’ continued to refer to everything there was – the whole shebang. The universe, however, was redefined to mean everything created by the Big Bang. This implied that vast regions that lay outside the creation event that formed our particular universe might exist. There might, in fact, be many more universes than just the one we inhabit.
Since the 1970s, some variety of this answer has been adopted by most mainstream cosmologists. This represents a significant modification of Lemaître’s original Big Bang model, which claimed to describe the creation of absolutely everything. The new Big Bang only describes the creation of our particular universe out of a pre-existing something. There’s no consensus, however, about what this something might have been. Perhaps it was a quantum vacuum in which random fluctuations of energy occasionally produced new universes. Perhaps it was a five-dimensional hyperspace inhabited by floating membranes of energy that spawned new universes every time they collided. Or perhaps (and this is currently the most popular belief) it was a ‘multiverse’ filled by a rapidly inflating field of negative energy out of which new universes constantly formed, like drops of water condensing out of steam.