本帖最后由 q5968661 于 2008-12-17 13:26 编辑
December 16th, 2008
CMB Timeline. Credit: NASA
Physicist Sean Carroll gave a wonderful talk at the June 2008 American Astronomical Society meeting about his "speculative research" on what possibly could have existed before The Big Bang. ( Here's an article about Carroll's talk.) But now Carroll and some colleagues have done a bit more than just speculate about what might have come before the beginning of our Universe. Carroll, along with Caltech professor Marc Kamionkowski and graduate student Adrienne Erickcek have created a mathematical model to explain an anomaly in the early universe, and it also may shed light on what existed before the Big Bang. "It's no longer completely crazy to ask what happened before the Big Bang," said Kamionkowski.
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No "Big Rip" in our Future: Chandra Provides Insights Into Dark Energy
Galaxy cluster Abell 85, seen by Chandra, left, and a model of the growth of cosmic structure when the Universe was 0.9 billion, 3.2 billion and 13.7 billion years old (now). Credit: Chandra
When you throw a ball up into the air, you expect gravity will eventually slow the ball, and it will come back down again. But what if you threw a ball up into the air and instead of coming back down, it accelerated away from you? That's basically what is happening with our universe: everything is accelerating away from everything else. This acceleration was discovered in 1998, and scientists believe "dark energy" is responsible, a form of repulsive gravity, and it composes a majority of the universe, about 72%. We don't know what it is yet, but now, for the first time, astronomers have clearly seen the effects of dark energy. Using the Chandra X-ray Observatory, scientists have tracked how dark energy has stifled the growth of galaxy clusters. Combining this new data with previous studies, scientists have obtained the best clues yet about what dark energy is, confirming its existence. And there's good news, too: the expanding Universe won't rip itself apart.
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