Every cosmologist and astronomer agrees: our Universe is 13.7 billion years old. Using cutting-edge technology, scientists are now able to take a snapshot of the Universe a mere heartbeat after its birth. Armed with hypersensitive satellites, astronomers look back in time to the very moment of creation, when all the matter in the Universe exploded into existence. It is here that we uncover an unsolved mystery as old as time itself — if the Universe was born, where did it come from? Meet the leading scientists who have now discovered what they believe to be the origin of our Universe, and a window into the time before time.
Where did the Universe Come from?
By Heather Quinlan, HowStuffWorks.com
The big bang theory holds that the entire universe was once packed tightly into an unimaginably dense and tiny space, known as a “singularity.” That is, until roughly 13.7 billion years ago, when a colossal burst of energy and pressure started to give rise to entire worlds, galaxies and interstellar particles, forming the universe as we know it today.
But what brought about that big bang?
Physicists are left scratching their heads at that question. Since the universe began on such a tiny level, the laws of relativity don’t fully apply. Instead, quantum theory, which deals with the lawless and bizarre world of the very small, must also be summoned. Successfully answering the question of what existed before the big bang would require bridging the gap between the so-far mutually incompatible worlds of relativism and quantum mechanics. But even though that bridge has yet to be constructed, theories abound.
“Our universe could have either popped into existence or collided with another universe,” theoretical physicist Michio Kaku told scienceline.org. “Big Bangs happen all the time.”
Building off that idea, cosmologists Paul Steinhardt and Neil Turok believe they have the answer, in what they’ve termed a “cyclic universe” — that our three-dimensional universe is but a much smaller part of an even larger multi-universe, one that exists in a space of 11 dimensions and contains other universes within. The lynchpin holding this idea together is “M-theory,” or the idea that our universe, as well as other universes, is actually a membrane. The big bang is the aftermath of a collision between two of these membranes.
This means that not only was there a time before the big bang, but that the universe we live in is not the only one. In fact, it may be one of an infinite number of universes, and the big bang may simply be a chapter in an even greater cosmic story.
The Big Crunch?
So even though we’re unsure how the universe began, are we closer to determining how it will end? Well, for every big bang, there may be a big crunch — a term that sums up what may befall our universe. The big crunch theory postulates that the universe will ultimately reach a point where it will no longer be able to expand, and gravity will force it to collapse into itself, returning it to its initial singularity state — where it may one day expand again in a big bang. But this shouldn’t be the stuff of nightmares, as there are cosmologists who think the universe may be a membrane that expands forever. For now, the end, like the beginning, remains a mystery.
Video (Playlist): http://www.youtube.com/user/Moesty19#g/c/5E3CF3EA699BC9E4