Einstein's theories of relativity entail a wide range of possibilities on how the universe began – if indeed 'began' is an appropriate characterization. For the most part the special and general theories of relativity are typically discussed in purely physical terms, that is, with regard to an essentially mechanical view of the universe governed by objects (mass) and concrete interactions (forces) (1920). Yet it is possible to discuss these theories in philosophical and logical terms because certain conclusions can be drawn from Einstein's discoveries that makes the questions of the universe's origin and ostensible decline seem rather perplexing.
The Movement Machine …
The logic of relativity is such that one can assume there are interactive relationships among mass, energy, time lapse and light speed. (Adams 1997). More specifically, as the speed of an object increases, its mass tends to increase as well. During that acceleration, time tends to slow down. Since mass increases and mass essentially equates with energy, the potential of the latter increases as well. In simple terms, the template is as follows. An acceleration in movement enhances everything we attribute to existence. Slowing down time allows for more intervals within time frames so that, for example, what we now define as a year would be of longer duration than in "slower" circumstances. By the same token, acceleration makes objects more massive, which means they have greater potential gravitational influence on each other as well as more potential energy to release. This kind of pan-embellishment makes it clear that our universe is kinetically driven – that speed of movement is, in a sense, the independent variable leading to existence.
In that context it is interesting (although hardly scientifically verifiable) to consider the opposite scenario – that of a slow-motion (decelerating) universe and its implications for existence, ie the physical sense of being.
First of all, starting with the premise that light speed causes a stoppage in time lapse, moving back from that point to slower rates of acceleration would by definition speed time passage. In other words, if one does not age at all at light speed, then reducing the speed toward a more normal rate would, by definition increase the rate of time lapse so that one would gradually begin to age faster. Therefore just as acceleration of movement slows time down, slowing the rate of acceleration causes time lapses to speed up – which means not only that we would age more rapidly, but that all developmental, entropic and evolutionary sequential phenomena in nature would proceed more quickly toward decay (which equates with entropy or "equilibrium)."
Since time and space are co-dependent, deceleration leading to compressed time scales would also compress spatial dimensions. By the same token, just as acceleration increases mass so would deceleration lead to a decrease in mass. Also, since mass equates with energy, slowing down acceleration would lead to a decline in energy as well.
Because, in that context, the speed at which the universe and its components travel would seem to be a central determinant of our universe's development and evolution it might be appropriate to refer to the cosmos as being kinetically driven, shaped and determined.
The scenario would obviously not come into play except at extreme levels of deceleration but the results of both extreme acceleration and deceleration are fascinating to consider. This is particularly true with regard to the possible final state of our universe.
Einstein's reversal …
According to principles of relativity theory, one would expect universal expansion to slow down at some point. The usual assumption is that by reversing gradually the fly-apart nature of an expanding universe gravitational influence would increase, leading to universal compression. Over time, one might expect the contraction the rate of contraction to accelerate exponentially until such time as the universe collapsed; conceivably reverting back to its original plasmic, "cosmic egg" status.
That scenario is disputed by some, such as Hawking (2005) and Guth (1997) but the expansion-contraction concept has a certain logical appeal – depending on how much matter (dark and otherwise) actually exists in the universe. Scientists have not yet detected sufficient amounts of dark matter to support the expansion-contraction theory. If the amount is insufficient, the universe will probably continue to spread out until material and force relationships are cancelled out by distance. At that point the universe will, like all things in nature, proceed toward a state of entropy. In that case no renewal being possible and our universe will have been a one hit wonder.
Suppose, however, that there was sufficient matter to cause eventual contraction. What would be the logical endpoint? Would it really be a expand / contract, oscillating universe that periodically dies (reaches a state of entropy), then is subsequently reborn through some baroque set of physical laws that would seem to repeal Newton's third law of thermodynamics, specifically the idea that once an object reaches entropy it's run is "over." Those questions are not easily answered, for a number of reasons.
First, if the original cosmic egg was in a state of entropy to begin with, it should not have re-generated – in other words it is hard to understand how the Big Bang could have emerged Lazarus-like from a prior state of entropy – that sort of thing does not happen in nature. This argument would also pertain to the notion of an alternating creation-destruction sequence. This raises the question of how the universe arose in the first place.
Stephen Hawking found this question both interesting and confusing and dealt with this conundrum by suggesting the idea of a universal "beginning and end" is a man-made conception, ultimately contraindicated by the laws of physics (2005).
There are a few ways to address the questions of origin and decay. One is to say the universe is inherently sequential, ie shifts back and forth (not inevitably but probabilistically) between states; ie. from an entropic, timeless, black hole with mass but no matter or capacity for three dimensional movement, and with implicit but not manifest energy – to a material, energized, expanding, time-governed entity as seen in our current universe. That model requires acceptance of the fact that "decay, equilibrium and entropy can be overcome (ostensibly in defiance of physical laws).
Another possibility (perhaps easier to conceptualize) is that the universe obeys the laws of physics, always has, always will and, never reaches a state of entropy due to an inherent a regulatory process that keeps it within the parameters of being,
The Regulatory Thesis …
The argument for a regulated universe-ie one that oscillates across a continuum but ever reaches a state of equilibrium, is as follows:
First, the assumption that universal contraction would inevitably increase gravitational influence might not be accurate, because as the universe contracted the capacity of objects to travel faster would decline – due in part to increasing limitations on space. Furthermore, as its speed decreased, so would its mass – just as the opposite occurs with acceleration (eg the mass of an object increases as it approaches light speed). Since movement dictates mass and since mass equates with energy, there would be a decline in both as contraction continued. Moreover, since gravity is dependent on mass and since mass declines with extreme deceleration, the influence of gravity would tend to decline as well. Finally, with less space in which to enact the laws of motion, the speed of contractual acceleration would itself decline, which would cause time to speed up – just as it slows down as it approaches light speed. With narrowed time spans, events would have briefer intervals to register interactions among matter and force.
In simpler terms, and in accord with Relativity Theory, just as acceleration enhances mass, energy, and by extrapolation gravitational influence, as well as prolonging time intervals (the slower time moves, the more opportunities events have to unfold) so would the opposite appear to be true. As time speeds up – in contrast to a decline in universal acceleration, the rate of entropy among existing objects and forces in the contracting universe might unfold more rapidly. As a result, for a given period of time, nothing would last for very long, which means interactive influence of force and matter would be ameliorated in the extreme. In other words, very little would happen as the contraction continued.
While Relativity Theory does not specifically address the opposite of time dilation, and focuses on the position of one observer relative to another in perceiving the rate of acceleration, there is evidence that clocks in some settings run slower as per slower rates of movement than others ( Ashby 2003). Moreover the relativity factor in
Einstein's theory is, while brilliant, somewhat understated. Speed is not simply a function of relative perceptions. For example if one ages slower at light speed than in more normal temporal circumstances there are concrete physiological, biological effects involved that are in fact absolute, rather than relative. In other words, if one ages slower it is not by comparison to other people. The concrete biological phenomena: still youthful skin, the superbly functional organs, the lack of age-induced limitations on hormonal and muscular formidability would be tangible. Thus, speed of movement has direct impact on nature even in absolute circumstances.
With regard to the re-expansion of the universe – a necessary reversal if one is to believe in a kinetically driven, self-regulating cosmos – the movement factor would once again be critical. As the universe slowed down during contraction, time would speed up. At some critical point in contraction, interactions would begin to once again accelerate because the time lapses between interactions would speed up. In other words, with smaller time intervals the interaction of mass and force would occur more rapidly. Once that process began, the universe would once again begin to re-accelerate and swing back until such time as it re-attained something like its current state.
In any case, the result of exponential deceleration would resemble a cybernetic-feedback process, analogous to the homeostatic mechanisms of organisms. In that context, speed, presumed here to be the prime, and independent ("kinetic") variable in universal operations, would provide a kind of checks and balances mechanism, keeping the universe on a continuum, always, and for all time operating within the parameters of physical laws; always extant, never quite reaching the point of equilibrium due to the cancellation / re-enhancement effect of deceleration and re-acceleration. In that case there would be no need to ponder the possibilities of extreme expansion or complete annihilation.
All of this is speculative of course, but perhaps the fact that light speed is a constant and anchor point feature of the cosmos might lead one to believe it serves as a gauge mechanism, and as a corollary, that motion and acceleration provide the lifeblood for a perpetual universe that is most fundamentally kinetic.
Adams, S. (1997) Relativity: An Introduction to Space-Time Physics, CRC Press
Ashby, N. (2003) Relativity in the Global Positioning System. Living Reviews in Relativity 6:16
Einstein, A. (1920) On the Idea of Time in Physics and Relativity; The Special and General Theories. Henri Holt
Guth, A (1997) The Inflationary Universe: The Quest for a New Theory of Cosmic Origin. Reading, Mass. Perseus Books
Hawking, S. (2005) The Origin of the Universe, Public Lectures.