Miércoles 18 de Julio de 2007, Ip nº 199

Astronomers spot most distant galaxies ever seen
Por Michael Kahn

Astronomers using a giant telescope say they have found glimpses of the most distant -- and oldest -- galaxies ever seen, a finding that will help provide clues to the origins of the universe.

The light the researchers viewed originated when the universe was only 500 million years old and has been traveling through distant space for billions of years, said Richard Ellis, an astronomer at the California Institute of Technology.

This means the team found galaxies further back in time than anyone has ever seen as scientists try to better understand how the universe was born some 13.5 billion years ago, he said in a telephone interview.

"These objects we have found are the earliest we believe that have ever been detected," said Ellis was due to present his findings of work he did with graduate student Dan Stark at a meeting of the Royal Astronomical Society later on Wednesday.

"The implication is these are the early generation of stars switched on when the universe was in its infancy."

The team used the giant Keck telescope in Hawaii, which boasts a light-gathering mirror measuring 10 meters in diameter and allows astronomers to look deep into space.

But Ellis and his team were able to look even farther by pointing the telescope though a natural magnifying glass in space made up of much closer clusters of galaxies which deflected light and made it easier to see more distant bodies.

This effect of light from distant bodies bending as it passes through the gravitational field of closer objects is known as "gravitational lensing" and is based on one of Einstein's early theories.

"We found areas of space which act as powerful magnifying glasses," he said. "Some of these places magnify the sky as much as 20 times."

The findings offer important clues into the origins of the universe, which scientists believe was created with an explosion of energetic radiation -- the Big Bang.

Ellis explained that during its first 300,000 years the universe was extremely hot before entering a dark period when stars had not yet formed.

The objects the researchers identified could provide a better understanding of the following period when stars started to shine after hydrogen clumped together and collapsed, he said.

"We are really witnessing our origins," he said. "It is exciting we can use this technique to get a glimpse of the universe when it was so young."


  11/07/2007. Reuters.