Paul Steinhardt and Neil Turok think they can explain why the cosmological constant is so teensy.
Ever since the 1960s, people assumed that the big bang was the beginning of time, because the laws of physics seem to break down there," says Turok. But the equations of string theory tell a different story, allowing time to exist before the big bang, he says.Lest the thought of an endless cosmic cycle make you ontologically nervous, don't worry; the mystery isn't solved just yet.
According to Steinhardt and Turok, today's universe is part of an endless cycle of big bangs and big crunches, with each cycle lasting about a trillion years. At every big bang, the amount of matter and radiation in the universe is reset, but the cosmological constant is not. Instead, the cosmological constant gradually diminishes over many cycles to the small value observed today
Perhaps a passing physicist could explain the shrinking constant's significance for the next cosmos--the one that will inherit an infinite national debt.
1 comment:
Having a cosmological constant tends to prevent your universe from re-crunching--our wimpy one certainly seems to be doing that to ours. So how do we cycle back to another bang? Something's missing from this story. I guess if you have a wimpy bang the universe wouldn't get stretched enough for the CC expansionary force to overcome the gravitational crunching force. So the current universe goes on forever, but we got here through a succession of wimpy-bang-crunches? Weirder things have happened, I guess.
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