news @ nature.com – Universe bounces back from the brink – Cycling cosmos obeys thermodynamics without ripping itself apart.

It has to be the closest ever shave. Two physicists have proposed that, a fraction of a second before a cataclysm that would destroy space-time itself, the Universe may escape by abruptly collapsing to a virtually empty state that ‘resets’ it for a fresh cycle of cosmic expansion.

The theory claims to reconcile the notion of a cyclic universe, which expands and contracts for eternity, with the second law of thermodynamics, which seems to imply that the current expansion cannot reverse.

As escape clauses go, this one is jaw-droppingly extravagant. Not only does the turnaround happen less than a thousand-trillion-trillionth (10-27) of a second before a ‘Big Rip’ in which everything falls apart, but it splits our Universe into countless new and independent ones.

So, now we know that a young Alvy Singer was fretting over nothing.

Mother(to doctor): He’s been depressed. All of a sudden, he can’t do anything.
Doc: Why are you depressed, Alvy?
Mother: Tell doctor Flicker. It’s something he read.
Doc: Something you read, heah?
Alvy: The universe is expanding.
Doc: The universe is expanding?
Alvy: Well, the universe is everything, and if it’s expanding, someday it will break apart and that would be the end of everything!
Mother(shouting): What is that your business? (to doctor) He stopped doing his homework.
Alvy: What’s the point?
Mother: What has the universe got to do with it? You’re here in Brooklyn! Brooklyn is not expanding!