Gravitational waves are the "smoking gun" of the Big Bang. Predicted by Albert Einstein's theory of general relativity in 1916, a massive object like Earth distorts space-time around it like a bowling ball dropped on a trampoline. The larger the object, the more space-time is distorted by it. If a marble were circling around the bowling ball on the dimpled trampoline, it would fall inward, toward the bowling ball, like a rock in space circling a planet. Gravitational waves are ripples in space-time that travel outward from a source. [VIDEO: Gravitational Waves Simply Explained With a Cube and a Marble] Scientists think that powerful gravitational waves are created when two extremely dense objects
LONDON, July 12 (UPI) -- We may be living in a second-generation universe. Scientists say the expanding cosmos may not be born of a virgin explosion. It could be the rebound from a former collapsed universe. Our existence may have a "Big Bounce" to thank, rather than a Big Bang. The Big Bounce theory isn't new -- it was first proposed in 1922 -- but cosmologists have struggled to explain how a collapsing universe would end in anything other than complete destruction. Now, a team of scientists have a working model of "bounced" universe -- and an answer for the question. Quantum mechanics saved the collapsed universe from complete destruction, researchers at Imperial College London say. The answer