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exploring: big bang > what powered the big bang

A new form of energy may have powered the Big Bang.

Although astronomers understand what the universe was like just a few seconds after the Big Bang, no one yet knows what happened at the instant of the Big Bang - or what came before. What powered the Big Bang? Where did all the stuff in the universe come from in the first place? What was the universe like just before the Big Bang?

Scientists have developed a number of new ideas about what might have powered the Big Bang. They are also creating bold new space missions to test these ideas.

The "inflationary universe."
The leading idea is called the "inflationary universe" model. The key assumption of this model is that just before the Big Bang, space was filled with an unstable form of energy, whose nature is not yet known. At some instant, this energy was transformed into the fundamental particles from which arose all the matter we observe today. That instant marks what we call the Big Bang.

A remarkable consequence of this model is that, if even a pinpoint of space contained this primordial form of energy, then the pinpoint of space would expand extremely rapidly and would bring into existence more of the same kind of energy. In fact, all the matter in the universe could have arisen from a bit of primordial energy weighing no more than a pea. This amazing scenario is a consequence of applying Einstein's theory of gravity to the inflationary universe model. Thus the known laws of nature can in principle explain where the matter and energy in the universe came from, provided there was at least a tiny seed of energy to begin with.

A model is useful only if it makes predictions that can be tested with evidence. The inflation model makes several testable predictions.   One of the most important is that the primordial energy would have been "lumpy" - i.e., unevenly spread out in space - due to a kind of quantum noise that arose when the universe was extremely small.   This pattern would have been transferred to the particles that burst into existence during the Big Bang. As a result, the matter that filled the universe then would not have been uniformly spread out; some regions would have slightly more matter, some slightly less. This lumpiness of the baby universe is fortunate for us: Had the universe been uniformly filled with matter, then stars and planets would never have formed. We wouldn't be here.

Evidence for the inflationary model of the universe.
If the inflationary universe model is correct, then we should see this lumpy pattern in the afterglow from the Big Bang. Astronomers have observed exactly this predicted pattern, in a spectacular picture of the Big Bang's afterglow, taken in 2003 by NASA's WMAP space probe. The picture shows us what the universe looked like about 300,000 years after the instant of the Big Bang.

The inflationary universe model is important because, for the first time, it gives us a glimpse of how nature may have arranged to create all the matter in the universe: only a tiny "seed" amount of space and energy would have sufficed.

But what was this primordial form of energy? And where did the "seed" of space and energy come from in the first place? How did the universe as a whole begin? Explore more in the next section >





















What was the Big Bang? -
What powered the Big Bang? -
Where did the universe come from? -

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