- A U S T I N, Texas - Looking back
in time at a tiny section of sky, the Hubble Space Telescope found there
may be 125 billion galaxies in the universe, about 45 billion more than
the last best estimate, astronomers reported today.
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- The new number was based on observations
by the orbiting telescope's Deep Field camera last October, when it looked
at a speck-sized area of the southern sky, taking what amounts to a visual
core sample of the heavens.
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- The Hubble telescope took a similar view
of the northern sky in 1995, and then estimated that there might be 80
billion galaxies in existence.
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- Harry Ferguson of the Space Telescope
Science Institute, which studies Hubble findings, said the southern observations
looked a bit further into the past than the northern ones, and managed
to detect dimmer objects in space, which accounts for the higher galactic
count.
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- 12 Billion Light Years Away
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- The Deep Field-South project looked 12
billion light years away in distance, back in time to a period perhaps
one billion years after the theoretical big bang that astronomers believe
created the universe. Hubble's glimpse of the southern sky took in an area
that would appear to be "about the size of a grain of sand held at
arm's length," Ferguson told reporters at the American Astronomical
Society meeting in Austin. But in that small segment of the sky, the telescope
spied 620 galaxies. Scientists extrapolated from that sample to theorize
that there might be 125 billion galaxies over the whole sky. "Anybody
could have predicted it," Ferguson said, stressing that by looking
further back in time, it was expected that more galaxies would turn up.
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- Weird-Shaped Galaxies
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- Ferguson and other astronomers at a news
conference acknowledged that some of the newly detected galaxies were oddly
shaped, unlike the symmetrical Milky Way that contains Earth and other
more familiar galaxies that are shaped like spirals and ellipses. These
newly-spied galaxies appeared to be a disorganized collection of loosely-bound
lumps. One astronomer likened their shape to a Danish pastry with raisins
and another called one group of these galaxies "a pastry shop."
The notion that there might be more galaxies than originally thought is
grist for astronomers trying to figure out how the universe developed,
especially in its earliest stages, Ferguson said.
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- Perhaps Ghost Galaxies, Too
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- Because these observations by Hubble
could see very faint objects whose light made its journey toward Earth
billions of years ago, it probably counted so-called ghost galaxies in
its estimate. Ghost galaxies are tiny, and consist of large amounts of
mysterious dark matter. Since astronomers believe that 90 percent of the
universe may be made up of dark matter, that makes the ghosts worth studying
and new astronomical instruments make this possible. A light year is the
distance light travels in a year, about 6 trillion miles.
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