Monday, May 28, 2007

No Evidence Of Big Band In 100 Billion Years?

This from the Scientific American:

Cosmologists have put themselves in the shoes of their future counterparts by pondering the consequences of dark energy, an enigmatic force discovered in 1998 that seems to be pulling galaxies apart at a steadily increasing clip. Eventually, this accelerating expansion of space will yank galaxies away from each other faster than light can travel between them, leaving our galaxy and its immediate neighbors isolated in a vast darkness.

In the process, all current evidence for the big bang would either vanish or become so diluted as to be imperceptible, says cosmologist Lawrence Krauss of Case Western Reserve University, who has studied the idea with Vanderbilt University physicist Robert Scherrer. "It will lead them to the wrong conclusion about what the universe is doing. The universe will look static, and that's vastly wrong, because the universe is expanding so fast they can't see it."

Take the expansion itself, first identified by Edwin Hubble in 1929 from the red tinge of distant supernovae. As space puffs up like a balloon, it stretches the wavelength of light from the bluer side of the spectrum toward the red. Krauss says that in 100 billion years or so the light from receding galaxies will have been stretched like taffy to a wavelength longer than our galaxy (100,000 light-years) and, therefore, be impossible for telescopes to detect.

The cosmic microwave background radiation, a residue of matter's first flash of light following the big bang, will suffer a similar fate. As its wavelength expands, Krauss says, the radiation will start to be soaked up by interstellar dust, potentially becoming indistinguishable from other light sources...

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