Hubble uncovers truth about distant galaxy

Oct. 16, 2007 at 3:19 PM
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WASHINGTON, Oct. 16 (UPI) -- The U.S. space agency's Hubble Space Telescope proved a long-held theory concerning the nature of a dwarf galaxy is incorrect.

Astronomers had identified I Zwicky 18 as one of the youngest galaxies in the universe. But Hubble astronomers have discovered it is, in fact, much older and farther away from Earth than thought.

Observations 40 years ago suggested the galaxy had erupted with star formation billions of years after its galactic neighbors, such as did the Milky Way. But the new Hubble data have quashed that possibility.

Hubble has found fainter older red stars contained within the galaxy, suggesting its star formation started at least 1 billion years ago and possibly as much as 10 billion years ago. The galaxy, therefore, might have formed at the same time as most other galaxies.

Hubble -- a joint National Aeronautics and Space Administration and European Space Agency project --also suggests I Zwicky 18 is 59 million light-years from Earth, nearly 10 million light-years more distant than believed.

The research, led by Alessandra Aloisi from the ESA's Space Telescope Science Institute, appears in the Oct. 1 issue of the Astrophysical Journal Letters.

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