Big Bang Theory

Was the Big Bang the Beginning?

In view of the fact that a beginning in physics implies a Creator, many physicists with a naturalistic orientation would like to avoid the necessity of such a beginning. For this reason, they have proposed that the big bang was not the beginning of the universe. Before we can assess this hypothesis, we will want to get a few facts about the contemporary big bang theory.

The Big Bang Theory was proposed originally by a Belgium priest by the name of Fr. George Lemaitre who used it to resolve a problem (the radial velocities of extra galactic nebulae) connected with Einstein’s General Theory of Relativity. Though Einstein did not at first affirm the idea of an expanding universe, he later believed it because of its overwhelming verification. Indeed, it is one of the most rigorously established theories in physics today.

Essentially, the contemporary Big Bang Theory holds that the big bang occurred approximately 13.7 billion years ago (plus or minus 200 million years). It may be analogized to a balloon blowing up where the elastic on the balloon is like the space-time field (in general relativity, space-time can actually stretch, expand as a whole, warp, vibrate, and change its coordinate structure according to the density of mass-energy in it).

Now, going back to our analogy, suppose there are paint spots all over the balloon; notice that as the balloon expands (i.e. as space-time stretches and expands as a whole), all the paint dots (which may be likened to galaxies) move away from each other. Our universe has been doing something like this for 13.7 billion years.

Our observable universe seems to have a finite amount of mass-energy. It has approximately 4.6% visible matter (matter-energy that can emit light, electromagnetic fields, etc.), 23% dark matter (interacts with gravity, but does not seem to have luminescent or electromagnetic activity), and 72.4% dark energy (which seems to be like a field attached to a space-time field causing space-time to accelerate in its expansion). The visible matter in our universe seems to be approximately 1055 kilograms which is approximately 1080 baryons (protons and neutrons – particles with significant rest mass).

Since the time of Fr. Lemaitre, the Big Bang Theory has been confirmed by multiple, distinct data sets which come together around a similar set of numbers and values: Edwin Hubble’s’ Redshifts (which shows that all galaxies are moving away from each other), Arno Penzias’ and Robert Wilson’s discovery of the 2.7 degree Kelvin uniformly distributed radiation which is the remnant of the big bang, evidence from the cosmic background explorer satellite (COBE), and further evidence from the Wilkinson Microwave Anisotropy Probe (WMAP). This is why most physicists consider the big bang to be a rigorously established physical theory.

Was the big bang the beginning of the universe? Many physicists think that it was because the big bang was the moment at which space-time came into existence and because there is no physical evidence for a period prior to the big bang. However, some physicists believe that the big bang was not the beginning of our universe which opens the possibility for a pre-big-bang period of indefinite length (perhaps avoiding a beginning and all of its implications for a creation). This hypothetical pre-big-bang period is made possible through quantum cosmology (which allows the universe to operate in a space-time smaller than the minimums required by general relativity). Currently, string theory is one hypothetical candidate for quantum cosmology in which some physicists (including Stephen Hawking) have placed considerable hope. (Those of you interested in additional detail on quantum cosmology and string theory will want to read the Postscript to Part One of NPG). String Theory allows for the possibility of higher-dimensional space, which in turn, allows for two possible pre-big bang periods:

1. A multiverse (a mega universe which coughs out multiple bubble universes, one of which is our universe) and

2. An oscillating universe in higher dimensional space (e.g. two three dimensional membranes interacting and colliding through a four dimensional bulk space-time).

It is not important to know all the details of a multiverse or an oscillating universe in higher dimensional space, because there is only one relevant question. Do these speculative scenarios themselves require a beginning or can they go indefinitely back into the past? It so happens that a considerable amount of work has been done in the area of space-time geometry proofs which conclude that all inflationary model universes, multiverses (which must be inflationary in order to exist), and oscillating universes in higher dimensional space must have a beginning. These extraordinary proofs suggest the probability that our universe (or any multiverse in which it might be situated) must have a beginning, which implies a Creator. So what are these proofs?