Universe’s Big Bang may end with a Big Rip

Guardian : Most scientists agree that the universe began with a Big Bang, but how it will end continues to be a matter of discussion. Various scenarios have been proposed, among them the Big Crunch, in which the universe’s expansion slows and gravity causes the universe to collapse in on itself, and the Big Freeze, in which the universe continues to expand to the point where matter becomes so spread out and cold that all movement ceases. The latest theory is the Big Rip, in which the universe’s ever-accelerating expansion results in the explosive tearing apart of all matter. In their paper in Physical Review D, Marcelo Disconzi of Vanderbilt University in Tennessee and colleagues reexamine the concept of cosmological bulk viscosity, or the ability of a fluid-like universe to expand or contract. They put forth the idea that the expansion of the universe could continue to accelerate until it reaches some critical point—the Big Rip—at which everything, even the constituents of matter, will be annihilated. Fortunately, that won’t happen for at least another 22 billion years.