What if the big-bang theory is wrong? What if the universe never began and will never end, driven forever to expand in a series of monster explosions and contract every eon or so in a cosmic crunch?
Princeton University physicist Paul Steinhardt suggested just that in a report that even he called "mind-bending."
The big-bang theory, accepted by many scientists for decades, holds that the universe was born some 14 billion years ago when an unimaginably small, dense entity blew up, sowing the seeds of every bit of matter and energy.
Soon after that first explosion, the universe expanded rapidly, in a phenomenon astronomers call inflation, and then continued to spread out at varying speeds until the present day, according to the big-bang theory. Under this theory, time would begin but never end.
But the model of the universe envisioned by Steinhardt and Neil Turok of Cambridge in the journal Science sees the big bang as merely a turning point on an infinite road: an endless series of big bangs make the universe expand and an equally endless series of subsequent crunches make it contract.
The current estimated age of the universe according to the big-bang theory would seem like the blink of an eye under the cyclic universe theory, which assumes the universe waxes and wanes in cycles lasting as long as trillions of years.
"Time does not have to have a beginning," Steinhardt said in a telephone interview. He said that what scientists theorize as the dawn of time might, in fact, be "only a transition or a stage of evolution from a pre-existing phase to the present expanding phase." Bureau Report