SKIRMISHER

Suddenly, the possibility that space and time existed before the big bang has become more comprehensible, and perhaps even compelling as a model for our universe. After some initial years of quiet development, there is now a surge of interest in the cyclic possibility, along with new motivations for considering it.

For example, Roger Penrose has argued that a cyclic model may be necessary to explain how the universe is compatible with the second law of thermodynamics, one of the most fundamental dictums of physics. According to the second law, entropy (the amount of disorder) always increases. Since the inflationary model creates an enormous amount of entropy, the universe must have begun with very little before inflation. However, there is no explanation for why this should be so. In fact, cosmologists often describe the universe right after the bang as being chaotic and random, suggesting high entropy. Penrose argues that some event must have preceded the bang to make the entropy low and that this event is likely to repeat in the future. Coming full circle, this seems to result in a cyclic universe.

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