Posted on 09/10/2002 1:55:07 PM PDT by 1bigdictator
Universe might yet collapse in 'big crunch'
11:08 06 September 02
Exclusive from New Scientist Print Edition
The Universe might yet collapse in a devastating "big crunch". Physicists have shown that even though its growth is speeding up, it could still start to implode by the time it is only twice its current age.
The Universe looks as if it will last forever, but we shouldn't jump to conclusions (Photo: SPL) "A few years ago, nobody would even think seriously about the end of the world within the next 10 to 20 billion years, especially since we learned that the Universe's expansion is accelerating," says Andrei Linde of Stanford University. "Now we see it is a real possibility."
In 1998, astronomers studying distant supernovae found evidence that the expansion of the Universe is getting faster. This suggests that some kind of "dark energy" is pushing space apart.
Most theories of dark energy propose that the Universe's accelerating expansion is driven by a cosmos-wide repulsive "scalar field" that has a uniform magnitude right across space. A similar energy field is thought to have made the Universe expand incredibly quickly just after the big bang, a period known as inflation. In August, Linde won the Dirac medal for his role in developing this theory.
Scientists have assumed that the repulsion of the field will drop as the Universe grows, eventually falling to zero. Though this would slow the rate of expansion of the Universe, it would never actually stop expanding. But Linde says this assumption could be wrong.
Minus infinity
He and his colleagues have shown that according to some theories of supergravity, which try to describe gravity within the context of quantum theory, the dark energy from a scalar field will do more than simply reach zero - it will become negative and possibly even plunge as far as minus infinity.
This would slow the rate of expansion of the Universe and then put it into reverse, causing space and time to collapse to a point in a big crunch.
Linde and his colleagues calculate that the typical time for the Universe to start this collapse would be in 10 to 20 billion years from now. Its current age is about 14 billion years.
"This was the greatest surprise," says Linde. "We might be in the middle of the life cycle of the Universe, not at the beginning."
With both collapse and indefinite expansion possible, we seem to be further than ever from predicting the fate of our Universe. But Linde says observations of supernovae, the leftover radiation from the big bang and galaxy distributions should help resolve the issue by pinning down the densities of dark energy and matter at different times in the past.
"It was never easy to look into the future, but it is possible and we should not miss our chance," says Linde. "We may be unable to change our fate, but we surely want to know it."
England's Astronomer Royal, Martin Rees of Cambridge University, is keeping an open mind. He agrees that a future collapse is possible. "Since we have no idea what the dark energy is, such scenarios cannot be ruled out," he says. "But ultra-long-range forecasts are all exceedingly speculative."
Hazel Muir
The next Big Bang?
(The pulse of God?)
Yup.
If you manage to hold your portfolio for 10 to 20 billion years, you'll be giving loans to Bill Gates Jr. to the 100th power.
Ya think?
Sounds more like a "pump and dump".
On a more immediate scale, I have an optometrist appointment next week. I hope it waits a while...
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