The nebulous dream world of cosmology
Physics in a fog
The branches of physical science known as astronomy and cosmology may be approaching another embarrassing Copernican moment, when everything gets turned upside down. Their beliefs are partly based on guesswork and mathematical exotica with little physical meaning, and no one dares say that the king (or the resulting theory) has no clothes.
A science in the fog
Cosmology the study of the development of the universe is intrinsically fascinating. Modern cosmologists use data and theory from astronomy, general relativity, mathematics, string theory and particle physics to attempt to explain the origin of our universe, and thereby of us. They are thus historians of a sort, and like historians they search for clues from the past that have survived to the present. For historians these clues are often documents and physical remnants; for cosmologists the clues are electromagnetic radiation in all its forms, including the states of matter, supplemented by experiments in particle physics.
While cosmologists are constantly getting more hard data, their science is still a theory-driven affair, where results from mathematical manipulations are judged by their fit to a generally accepted model of the universe's origin and development, optimistically named the "standard model". Central to this model is the idea that our universe is the only universe (in our four-dimensional space-time), and that its space is all the space there is (again, in our four-dimensional space-time). Which begs for a definition of "space". Conventional astronomers had been relatively happy with "space" being the apparently unending nothingness through which galaxies and other celestial objects travel. But with the discovery, nearly a hundred years ago, that what we can see of our universe appears to be expanding from a distant center, the conclusion was inescapable that the expansion originated at some time and place. And the hypotheses (cosmologists often call their hypotheses "theories") brought forth to explain this expansion did not jell with observed times and velocities until the idea was launched that the expansion was not merely of matter into space, but rather an expansion of space itself.
What does the cosmologist mean by "space", and by the idea that space is expanding? He may not be able to explain it without recourse to something as esoteric as many-dimensional mathematical manifolds. But put simply, the idea is that a mathematical coordinate grid (like a Cartesian grid) overlain on space has gridlines of changeable values. Thus, points on the grid that may not look farther apart a second later are in fact farther apart because the scale has changed in that second, i.e., space has expanded. (An equivalent and perhaps more intuitive interpretation would be that the gridlines are flying apart, so that distance has been created between objects on the grid without the objects actually moving in the grid. These two interpretations amount to the same thing, because we don't have any absolute measures of distance - or of time or speed, so we can't know whether space is expanding or the scale is changing.) So "space" is to the cosmologist a mathematical concept, without any necessary connection with what the layman calls space. Whether the cosmologist's space actually has a physical meaning is not clear, since it amounts to a theoretical result of abstract mathematics, not arrived at until the 1980s. But the cosmologist is fond of the idea, because without it Einstein's result of the absolute speed of light could not survive. The cosmologist would rather operate with weird space than give up on Einstein. But in the end, the concept of expanding space (whatever that is) is a convenient, if fantastic, explanation without strong proof, though there are a number of observations that have been interpreted as consistent with this theory.
The cosmologists' insistence on only a single universe (in our dimension) similarly lacks proof, and has required continual tweaking with new "fudge factors" to keep it afloat. (The idea of space being created in the Big bang seems to preclude other universes.) Their current faith recalls previous folly in the astronomical sciences: Thousands of years ago astronomers/astrologers believed that Earth the only terrestrial body they knew was the only such, but then they discovered that some of the slowly moving points of light in the sky (the Greeks named them "planets" = wanderers) were also terrestrial bodies, some a lot like ours. Then for a long time astronomers believed there was only one sun and solar system because that's all they could see, but then they found that the twinkling points of light in the sky were also suns like ours. And it's not so long ago that astronomers believed the Milky Way contained all the stars in the universe, because they couldn't see any outside the Milky Way. Then, in the 20th century, it was found that some of the fuzzy blobs in the telescopes were galaxies, organized systems of hundreds of billions of stars, and that the Milky Way was just an average galaxy. Time and again, astronomers have firmly believed that the extent of the cosmos was limited to what they could see.
So the current limitation on astronomical thought is again that what they can see one universe is all there is. There is nothing outside our universe, because we can't see anything there. Haven't we heard this before? And on that firm ground the cosmologists have built their "standard model" of the "big bang" that started everything about 13½ billion years ago. There's no room in their model for other universes, at least not in our everyday four-dimensional world. Other universes will only be permitted in other dimensions.
A touch of reality
Here's a reliable principle of the natural sciences: Nature never makes just one of anything. Events happen when the conditions required for their happening exist. That is, when the causes of the event are present, and the environment that permits the event is in place. The fact that a natural event has occurred is proof that it can occur; that is, that the natural cause required for its happening, as well as the needed conditions, can occur and have occurred. And this knowledge suggests that whatever has happened once can happen again, and the vastness of time and space makes it likely that what has happened once has happened more than once. We do not know of a case of a unique type of natural event or object. And since we know conditions that have brought about the formation of a universe have occurred at least once, it is not farfetched to think that it has occurred more than once.
Someone who has never seen sand or water, if shown such natural miracles as a grain of sand and a drop of water, could reasonably conclude that there must be a mechanism that has made them, and therefore it's likely that there are more grains of sand and drops of water; these didn't just happen once. And that would be correct. Similarly, the Earth is not the only planet because during the immensity of time and space the mechanism and conditions that created the Earth must statistically have occurred many times. The Sun is not the only sun (i.e. star) and the Milky Way is not the only galaxy, for the same reason. And the universe? Just like ancient astronomers, modern cosmologists have assumed that the limit to their physical perception equals the limit of reality, and have built their entire cosmological theory on that flimsy assumption. And as back then, they're likely to have guessed wrong.
The mental gymnastics that cosmologists have exercised in order to make the data fit their "standard model" remind us of the pre-Copernican period when astronomers resorted to fantastic creativity in order to make their theory of an Earth-centered universe fit with the increasingly bothersome observational data. They constructed complex astrolabes that showed Mercury and Mars moving along impossible paths - stopping and reversing direction at times, or suddenly doing a tight loop before resuming their normal course. By use of these ever more complex devices, astronomers up to the 17th century were actually able to simulate the movements of the planets as they appeared from Earth. But as we know, these fantasies had little to do with the actual movements of the planets, and little to do with physical reality. After Copernicus, the astronomers' more and more fantastic explanations to avoid facing the truth eventually popped like soap bubbles and were shown to have no substance. ( I'm reminded of Prospero's words in "The Tempest"; they were "melted into air, into thin air ... baseless visions...such stuff as dreams are made on ...") Current astronomers and cosmologists, with their invented "inflation", "dark matter" and "dark energy" among other unverified theoretical constructs, may be on the same shaky and nebulous ground as the pre-Copernican "Ptolemaic" astronomers.
My beef is not with the fact that cosmologists have hypotheses and theories. Bless them for it; those are necessary for the advancement of science. My complaint is that scientists have fallen in love with their hypotheses, have become blinded by their current star status in the vanguard of science, and have promoted their hypotheses as fact to a scientifically naïve world hungry for truth about the universe. They have perhaps themselves lost sight of the vast uncertainties in cosmological theory.
Modern cosmologists (e.g., Hawking) have proclaimed that there existed, before the Big Bang, a "singularity" of infinite density. This is on the face of it ludicrous, and was based on Hawking's assumption that relativistic physics operates conventionally at all densities. But matter can't have infinite density. If it did, it would retain infinite density no matter how much it expanded or was diluted, since you cannot divide infinity and arrive at a finite result. Infinite density also implies infinite mass, an equally silly concept. The irrationality of these ideas have not prevented them from being frequently put in print. No, if there was a big bang, the precursor was very likely quite dense, but only finitely dense. This means that we could place a number on its mass/energy, and if Einstein was right (mass/energy cannot be destroyed) this should be equal to the total mass/energy still present in our universe. All we have to do is to measure that (wink, wink).
But in recent years, some cosmologists have recognized Hawking's folly of an infinitely dense singularity, and have come up with the more attractive hypothesis nicknamed the "Big bounce," which proposes that the current expansion of the universe started as a result of contraction of the previous phase of the universe. The contraction would have proceeded to a given density (determined by restrictions of quanturm effects) before again exploding. This avoids the problem of infinite mass, though like other cosmological hypotheses it leaves the problem of ultimate origins untouched. In this respect it just kicks the can down the road. Both the Bang and the Bounce hypotheses bring the universe to an unpleasant demise: if there's enough matter in the universe to gravitationally halt the expansion, the universe will collapse and extinguish itself (or re-expand). If there's not, the universe will expand forever into the dark and cold void, eventually to disappear as faint traces. Indeed, recent disturbing calculations have suggested the latter fate.
In just the past fifteen years, some unexpected values of red-shifts among the galaxies in our local area of the universe have been interpreted as gravitational anomalies, suggesting that some unaccounted-for gravitational attractor is at work. The currently popular hypothesis is that an undiscovered but assumed form of energy "dark energy" is responsible for the anomalies and for the puzzling finding that, based on red-shift values, the expansion of the universe appears to be accelerating (requiring a "pushing" force if within the universe), rather than slowing as expected. No plausible physical force has yet been proposed to account for these findings, and "dark energy" remains a myth, but one that cosmologists have put their faith in, as it is needed to rescue the standard model. (It will occur to the reader that a cosmos of many universes could provide the mass outside our universe to accelerate its expansion through normal attractive gravitation, rather than the mythical repulsive force required within our universe to do that job.)
Astronomers and cosmologists are also busy looking for light from the first stars, formed in the first billion years after the big bang. There have been published claims that stars 12-13 billion light years distant have been found in other words, their light has been traveling for 12-13 billion years before reaching us. This raises a problem for those who are geometrically inclined: If the Big Bang (or the Big Bounce) hypothesis is correct, and using ordinary four-dimensional geometry, there is simply no way that a light source existing in the first "billennium" post-Big Bang could be located at a place where its light would take 12-13 billion years to reach our current position at our current time. Light emitted from any source in the universe that existed 12-13 billion years ago would have passed our current position many billions of years ago, unless the average rate of the universe's expansion has been greater than about half the speed of light, which, of course, it has not been. (Based on current red-shift values, our estimate of the current rate of expansion is a small fraction of this.) When a cosmologist is asked about this problem of geometry, the answer is typically that four-dimensional geometry doesn't apply, since the universe's expansion is not of the normal explosive variety, but space itself has expanded, and therefore light has not traveled as expected. The universe has apparently expanded faster than the speed of light over a long period, so that light from the early universe has lagged behind has in fact appeared to move in reverse in relation to its local expanding space. Odd though, that the galaxies and their stars got expanded along with the space, while light's photons didn't get to go along but got left behind a desperate hypothesis difficult to explain. Another problem with this explanation is that the astronomers who measure these enormous distances use the same techniques they use on closer stars: straight-ahead linear geometric positioning, and the assumption of perpendicular light transmission to assess the red-shift. Thus the problem of the anomalous distance-calculation for stars proposed to be 12-13 billion light years distant remain; there's an unresolved conflict and we may eventually find that the assumptions behind the red-shift method of calculating distances to light sources have been too simplistic.
A happier cosmos
There are indeed many "issues" with current cosmological beliefs, and interestingly, a cosmos of many universes may provide plausible answers to many of the logical conflicts in the standard model. It could provide gravitational attractors outside our universe that would obviate the need for fudge factors like inflation, dark energy and dark matter. It might provide a clue to the evolution of universes, as some of these might expand into others, with the added gravitational mass bringing about a collapse to a dense state from which it might explode again. It may even provide a clue to the quasars are some of these actual exterior universes, seen as a point source because of their extreme distance? A cosmos of many universes might even bring us back to four-dimensional space-time geometry, consigning the strange idea of expansion of "space itself" to the philosophical scrapheap. Sadly though, discovery of a multi-universe cosmos would not get us much closer to the origin or the driving force of the cosmos. We'd just be kicking the can again.
I'm not campaigning for a multi-universe model (I can't even say I believe in it), but only for considering that possibility. Despite the cosmologists' argument that there's no proof of more than one universe - and that it would therefore be unscientific to speculate about it - there's no proof that only one universe exists, either. We know one universe has formed, so ... why only one? Denial of the possibility of multiple universes is required in order to maintain the cosmologists' standard model, but it makes a darned poor basis for proclaiming the current model to be fact.
H. Paul Lillebo