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Astronomers Discover Galaxy Believed to Be Most Distant

By Kathy Sawyer
The Washington Post

Astronomers have detected the most distant known object in all creation, a young galaxy that existed when the universe was only 6 percent of its present age.

The discovery, announced Thursday, stretches the reach of human perception 90 million light-years farther than it had extended before, to the mysterious period less than a billion years after time and space began in the Big Bang explosion, scientists said.

The finding offers tantalizing encouragement that the emerging generation of large, ground-based telescopes will unveil the elusive primeval galaxies of that epoch, when the first generations of stars formed.

"It's an extremely exciting discovery, since so little is known about this stage of the universe in terms of the objects that lived there, or how galaxies - giant collections of stars - might form," said Arjun Dey, a postdoctoral fellow at Johns Hopkins University in Baltimore, who led the team that made the discovery.

As the cosmic "egg" exploded, according to Big Bang theorists, the cosmos was a smooth soup of warring subatomic particles. As it expanded, the universe cooled and somehow transformed itself into the landscape of star-filled galaxies that we see. Just how, and when, that transformation occurred is one of cosmology's great mysteries. Astrophysicists are unable to test, refine or refute theories about how galaxies form without direct, observational evidence.

"We are trying to find baby galaxies," said Dey. His team used the largest optical and infrared telescopes in the world - the 10-meter Keck I and II complex atop the dormant volcano Mauna Kea in Hawaii. "These are galaxies that are essentially collapsing from a large gas cloud and forming their first generation of stars."

Because of its great distance, and the constant speed of light, the researchers said, they see the early galaxy (known as 0140+326RD1, or "RD1" for short), a relatively short 820 million years after the universe sprang into being as a uniform, expanding fireball of particles. (This assumes the universe is about 13 billion years old, a figure that is debated.) This means the light has traveled a distance of about 12.22 billion light years.

The discovery "significantly expands our reach into the known universe," said astronomer Steven Maran of the American Astronomical Society.

Frederic H. Chaffee of the Keck Observatory joined this search to help confirm the discovery. The team also included astronomers Hyron Spinrad, Daniel Stern and James R. Graham, of the University of California at Berkeley.

The finding gives astronomers hope that the embryonic stages of galaxies similar to today's large spiral and elliptical galaxies might be bright enough to be seen by the Kecks and other large instruments.