What Is the Oscillating Model of the Universe?

DR. CRAIG: Oscillating models of the universe hold that the expansion of the universe will slow and then come to a halt and then the force of gravity will pull everything back together again, but then it will rebound to a new expansion which will go to its ultimate limit, and then gravity will again pull it all back together again, and so on and so on from eternity past. So the universe on this model is sort of like an accordion expanding and contracting, expanding and contracting from eternity past. These models were proposed during the 1970s by various Soviet scientists who were in some cases explicitly committed to dialectical materialism and therefore very uncomfortable with the absolute origin of the universe predicted by the standard Big Bang model, and they sought to avoid it through these oscillating theories. Unfortunately, these theories soon succumbed to criticism. It turned out that they were physically unrealistic, and moreover they actually implied the very beginning of the universe that they sought to avoid because what happens in such a universe is entropy is conserved from cycle to cycle to cycle. That is to say, entropy continues to grow, and the effect of this is to make each cycle (or each oscillation) longer and larger. So as you trace the expansions back in time, they get smaller and smaller and smaller until you come to the origin of the universe prior to the smallest cycle. In fact, the astronomer Joseph Silk estimates on the basis of current entropy levels that even if the universe were, per impossibile, oscillating, it could not have gone through more than 100 previous oscillations.