Tantalising evidence hints Universe is finite

WDragon

19:00 08 October 2003 by Hazel Muir

Perplexing observations beamed back by a NASA spacecraft are fuelling debates about a mystery of biblical proportions - is our Universe infinite? Scientists have announced tantalising hints that the Universe is actually relatively small, with a hall-of-mirrors illusion tricking us into thinking that space stretches on forever.

However, work by a second team seems to contradict this, and scientists are now busy trying to resolve the conundrum. "Whether space is finite is something people have been asking since ancient times, and probably before that," says mathematician Jeffrey Weeks from Canton, New York. "If we resolved this and confirmed that space is finite, this would be an enormous step forward in our understanding of nature."

At the centre of the debate are observations by NASA's Wilkinson Microwave Anisotropy Probe (WMAP), which was launched in 2001. The probe measures temperature ripples in the "cosmic microwave background", the afterglow radiation from the big bang fireball.

Astronomers are interested in how strong different sizes of ripples are, as this reveals vital information about the early Universe, and might tell us how big the Universe is today. Many astronomers suspect that the Universe is infinite.

In that case, the microwave background ripples should have an unlimited range of sizes. But while WMAP's observations of small-scale ripples have matched predictions for an infinite Universe almost perfectly, the large-scale measurements have not. On the largest scales, WMAP has shown that the ripples almost disappear (see graphic, top).
Hall of mirrors

It could just be down to chance. Computer simulations that model the birth of the microwave background create this pattern once every few hundred runs. But it could mean that space itself is not big enough to support the broadest ripples, according to Weeks.

"Just as the vibrations of a bell cannot be larger than the bell itself, any fluctuations in space cannot be larger than space itself," he says.

Weeks and his colleagues, a team of astrophysicists in France, say the WMAP results suggest that the Universe is not only small, but that space wraps back on itself in a bizarre way (Nature, vol 425, p 593).

Despite being finite, the Universe would not have any kind of edge. If a spacecraft blasted off in what we'd perceive to be a straight line - the line a beam of light would follow - it would eventually end up back where it started.

Because of this odd wraparound effect, the light from one galaxy could follow two different routes to the Earth, so the same galaxy would appear in two different parts of the sky. Effectively, the Universe would be like a hall of mirrors, with the wraparound effect producing multiple images of everything inside.




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http://www.newscientist.com/arti ... erse-is-finite.html

江左

where is de beef

WDragon

回复 2# 江左


???????????

马甲.真

finite space....恩

if i go straight to any direction, i will be back!!!!

WDragon

回复 4# 马甲.真


then ur lost!