Yahoo - Astronomers Debate a More Youthful Universe
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From: Peter Langston <psl>
Date: Thu, 9 May 96 20:43:09 -0700
Subject: Yahoo - Astronomers Debate a More Youthful Universe
From: Dan Tenenbaum <firstname.lastname@example.org>
This is very interesting. Let's make it even more interesting.
I'm taking wagers on the actual age of the universe.
Send me your money along with your guess for the age of the universe,
and I'll pay out the bets when scientists determine beyond a doubt
the actual age.
Thursday May 9 4:58 PM EDT
Astronomers Debate a More Youthful Universe
WASHINGTON (Reuter) - Astronomers who gazed deep into distant galaxies with
the Hubble Space Telescope said Thursday the universe might be billions of
years younger than previously thought -- and so might the oldest stars.
Two separate teams of scientists arrived at different theoretical ages for
the universe -- one team estimated it at 9-12 billion years and another at
11-14 billion years -- but both are far younger than earlier estimates of
15-20 billion years.
The new numbers cast doubt on how old the oldest stars might be, according
to a briefing at National Aeronautics and Space Administration headquarters.
Stellar evolution specialists -- the scientists who estimate the ages of
stars -- have put the oldest stars at perhaps 12-16 billion years of age.
That would plainly have to be refigured if the universe itself is younger.
``A point of great interest is whether the age of the universe arrived at
this way is really older than the independently derived ages of the oldest
stars,'' said Abhijit Saha of the Space Telescope Science Institute in
Baltimore. Saha was on both scientific teams.
The two teams are trying to find the elusive Hubble Constant, which is a
formula for telling how fast the universe is expanding following the
theoretical Big Bang that started it all.
Knowing the Hubble Constant, named for astronomer Edwin Hubble who also gave
his name to the orbiting Hubble telescope, would allow astronomers to
pinpoint the age of the universe.
To this end, the two teams of astronomers looked at two different galaxies
dozens of light-years away from Earth, focusing on bright stars known as
Cepheids, which are used as accurate mileposts to mark vast distances in
space. A light-year is about six trillion mile, the distance light travels
in a year.
Using these bright stars to guide them, the two teams measured the Hubble
Constant five different ways, said Wendy Freedman of Carnegie Observatories
in Pasadena, Calif., who led one of the two teams.
The results for the two teams, while different, were closer than they ever
have been, the astronomers said.
But the difficult question of how old the oldest stars are remains.
``The ages (of the universe) are coming out on the low end, and it's
somewhat uncomfortable,'' astronomer David Spergel of Princeton University
told reporters. He said it was time to closely examine estimates of the
oldest stars' ages.
Once that is done there could be another question to answer, Freedman said,
because the oldest stars could not form instantly after the Big Bang, and
may have been born a billion years or more afterward. That would make the
oldest stars even younger.
© 1996 Peter Langston