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Embargoed until 7 A.M. EDT
NSF PR 98-88 - December 18, 1998
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NSF Telescope Sheds Light On Fate Of Universe
Researchers from Carnegie Mellon University, using
a National Science Foundation (NSF) microwave telescope
in Antarctica, have made a crucial measurement of
cosmic background radiation that may help science
to settle a fundamental question of whether the universe
will expand forever or collapse back upon itself.
Scientists measured the dimensions of extremely distant
gas clouds with the Viper Telescope, operated by the
Center for Astrophysical Research (CARA) in Antarctica
at NSF's Amundsen-Scott South Pole Station. Jeffrey
Peterson, a Carnegie Mellon astrophysicist and the
lead scientist on the Viper project, announced the
findings on Dec. 18 in Paris, France at the Symposium
on Relativistic Astrophysics. The biennial meeting
attracts the world's foremost astronomers and astrophysicists.
"These findings indicate that the material of the
universe was given just the right kick by the Big
Bang to expand forever, never collapsing, but also
never becoming so dilute that gravity can be ignored,"
according to Peterson. "This delicate balance is hard
to understand unless inflation theory, or something
akin to it, is correct."
Viper is used to make images of the faint structure,
an anisotropy, seen in the sky. Astrophysicists widely
accept that if the expansion of the universe were
slowing, the glowing clouds of gas observed with Viper
would be, in astronomical terms, relatively close
by and would measure as much as one-half degree of
arc across the sky. The discovery announced this week—that
the size of extremely distant gas clouds is, indeed,
one-half degree on the sky indicates that the expansion
of the universe is slowing at just the rate predicted
by inflation theory.
Inflation theory holds that just after the Big Bang,
as the universe expanded and cooled, it passed through
a critical temperature, currently thought to be 100
billion degrees—which changed the character of the
laws of physics. As the proto-universe passed through
this critical temperature threshold, there was an
enormous release of energy, which caused the universe
to "inflate,' or to dramatically increase in size.
This inflation process would have caused the universe
to expand with a precise "escape velocity," which
would provide an explanation for the Viper findings.
The newly released easurements indicate that the universe
has just such an escape velocity, Peterson stressed.
The anisotropy measurement is just a small part of
the data collected from the telescope, which provides
a snapshot of the universe as it was 300,000 years
after the Big Bang, the cataclysmic event that set
in motion the forces that created today's universe.
Previous cosmic background telescopes have been smaller
than Viper and have not been able to focus in fine
enough detail to measure the clouds as viper can.
However, the CARA group's work with these earlier
prototypes was critical to the new discovery. Karl
Erb, the director of NSF's Office of Polar Programs,
said "This advance is a fitting testament to the vision
and dedication of the CARA scientists whose pioneering
work proved that the South Pole is an ideal site for
these delicate measurements." The two-meter Viper
telescope began operation only last February.
Further observations by Viper and other telescopes
under development by CARA's member institutions are
planned to verify the newly released result.
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