[ExI] dark constant
thespike at satx.rr.com
Fri Dec 19 02:59:54 UTC 2008
Dark energy expands and contracts universe
Thursday, 18 December 2008
WASHINGTON: Mysterious dark energy works simultaneously to expand the
universe and shrink objects inside it, astronomers have found.
"This result could be described as 'arrested development of the
universe'... Whatever is forcing the expansion of the universe to
speed up is also forcing its development to slow down," said Alexey
Vikhlinin of the Smithsonian Astrophysical Observatory in Massachusetts.
Vikhlinin was the lead researcher of the study, to be published next
year in the Astrophysical Journal.
By studying how gravity competes with the expansion of galaxy
clusters, using NASA's Chandra X-ray Observatory, "a crucial
independent test of dark energy" has been found, said the researchers.
After years of research, scientists now believe that dark energy
makes up about 70 per cent of the universe, and is "a form of
repulsive gravity that dominates the universe," the researchers
wrote, "although [we] have no clear picture of what it actually is."
The discovery of dark energy's dual effects of expansion and
contraction sheds light on changes in the universe to come: "What
this means for the future of this universe is that accelerated
expansion will proceed forever but will probably not result in a Big
Rip," said Vikhlinin.
"That is, nearby galaxies will eventually disappear from our sight,
but the structures already formed by clusters of galaxies and our own
galaxy will not be torn apart, not in the near future anyway."
The new research provides the "strongest evidence yet that dark
energy is the cosmological constant," Vikhlinin said, being similar
to the energy of empty space. "Or in other words, that 'nothing
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