Not a Bang, but a ratatatat!

[Botnst]

Will our universe bounce?

According to the big bounce picture formulated by theoretical physicist Abhay Ashtekar and others, the cosmos grew from the collapse of a pre-existing universe. Will the same fate await us?It depends. We used to think that the universe was dominated by the gravity of its stars and other matter: either the universe is dense enough for gravity to halt the expansion from the big bang and pull everything back, or else it isn't, in which case the expansion would carry on forever. However, observations of distant supernovae in the past 10 years have challenged that view. They show not just that the universe is expanding, but also that the expansion is speeding up due to a mysterious repulsive force that cosmologists call "dark energy". So if the universe fails to contract, has it already bounced its last bounce?Perhaps not. Cosmologists are still very much in the dark about dark energy. Some theoretical models speculate that the nature of dark energy could change over time, switching from a repulsive to an attractive force that behaves much like gravity. If that happens, the universe will stop expanding and the galaxies will begin to rush together. A question mark also hangs over the universe's matter and energy density, which we have not measured with sufficient accuracy to be sure that the universe will not eventually stop expanding. If it turns out to be a smidgen greater than current observations, then it is a recipe for cosmic collapse.According to the big bounce, in both scenarios the universe will eventually collapse until it reaches the highest density allowed by the theory. At this point, the universe will rebound and begin expanding again - the ultimate in cosmic recycling.

http://www.newscientist.com/article/mg20026861.500-did-our-cosmos-exist-before-the-big-bang.html?full=true