- Shattering a record established just
6 weeks ago, astronomers have discovered the most distant object ever seen,
an infant galaxy that lies some 12.3 billion light-years from Earth.
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- That immense distance means that the
light now reaching Earth left the galaxy when it was less than 800 million
years old. Details about the finding appear in Saturday's edition of Science
News.
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- Astronomers observed the object, along
with several other galaxies that are nearly as distant, with one of the
twin Keck telescopes, the world's largest visible-light telescopes.
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- To search for distant galaxies, Lennox
L. Cowie and Esther M. Hu of the University of Hawaii in Honolulu and Richard
G. McMahon of the University of Cambridge, England, resurrected an old
strategy -- detecting a particular wavelength of light emitted by hydrogen
atoms -- that had not been successful with smaller telescopes.
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- The researchers say the method promises
to reveal some of the very first galaxies in the cosmos, those that were
in existence when the universe was only about 500 million years old.
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- Astronomers often express cosmic distance
in terms of "redshift," the amount by which the expanding universe
has shifted the light emitted by a galaxy to redder, or longer, wavelengths.
The more distant the galaxy, the greater the redshift. The previous record
holder, discovered by another team in March, has a redshift of 5.34. The
newly found galaxy has a redshift of 5.64 and hails from about 60 million
years earlier in cosmic history.
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- That difference in time may not seem
like much, but a small interval may have made a substantial difference
in the properties of the universe when it was very young.
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- "As any mother could tell you, a
year's growth makes a much bigger difference in appearance and character
in a toddler than in someone age 20," Hu says.
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- The team will describe their work in
an upcoming Astrophysical Journal Letters.
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