Archive for Monday, February 16, 2004

New galaxy discovered

Confirmed find would be most distant in universe

February 16, 2004


Tapping the powerful Hubble Space Telescope and a rare quirk of cosmic physics, astronomers have discovered the most distant galaxy in the universe, a faint, record-setting smear of light that flared 750 million years after the big bang.

If confirmed, astronomers said, the discovery could provide new clues to fundamental questions such as when stars first began to shine.

The infant galaxy, yet to be named, was found nestled among a massive galactic cluster known as Abell 2218. Richard Ellis, an astronomer at the California Institute of Technology in Pasadena and member of the discovery team, said the object is roughly 13 billion light-years away. One light-year is the distance light travels in a year, about 5.8 trillion miles.

The galaxy, said Ellis, likely was among the first formed after the mysterious period astronomers refer to as the "Dark Ages," an epoch before the lights in the universe came on. "In human terms, the universe isn't even on its feet yet. It's a toddler," he said.

A paper describing the find will be published in The Astrophysical Journal.

Ferreting out so distant and dim an object is an extraordinary technical feat, astronomers said. To do it, Ellis and his team turned to two of the world's most powerful telescopes.

But the astronomers said even the most powerful telescopes -- Hubble's Advanced Camera for Surveys and the W.M. Keck Telescope on Mauna Kea in Hawaii -- weren't powerful enough to see the infant galaxy. Ellis and his team also took advantage of a rare cosmic quirk known as a "gravitational lens" that naturally magnifies light from distant objects.

Gravitational lenses are so rare that astronomers know of fewer than 30 in the universe. They arise when light emanating from a distant star is amplified by the gravitational field of a massive object in its path -- in this case, the galactic cluster Abell 2218.

In all, the newly found galaxy is less than one-tenth the size of our own, the Milky Way. Preliminary evidence also indicated it contains huge stars many times the size of our sun.

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