Galaxies farthest, and earliest known found

[Owlscrying]

July 10

Astronomers have found evidence for the most distant galaxies ever detected.

The galaxies are seen as they existed just 500 million years after the birth of the universe.

Their light, traversing the cosmos for more than 13 billion years, was seen only because it was distorted in a natural gravitational lens created by the gravity-bending mass of a nearer cluster of galaxies

"Gravitational lensing is the magnification of distant sources by foreground structures," explained Caltech astronomer Richard Ellis, who led the international team. "By looking through carefully selected clusters, we have located six star-forming galaxies seen at unprecedented distances, corresponding to a time when the universe was only 500 million years old, or less than 4 percent of its present age."

The universe is estimated to be 13.7 billion years old, so that puts the newfound galaxies at 13.2 billion light-years away. A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers).

The team found the galaxies using the 10-meter Keck II telescope atop Mauna Kea on the Big Island of Hawaii.

The galaxies offer a glimpse of an era shortly after the first stars formed.

After the theoretical Big Bang, there were no stars. Eventually, a thick "fog" was effectively burned off by hot, young stars, ending what's called the cosmic Dark Ages.

That we should find so many distant galaxies in our small survey area suggests they are very numerous indeed. The estimate of the combined radiation output of this population could be sufficient to break apart (ionize) the hydrogen atoms in space at that time, thereby ending the Dark Ages.

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