Herschel telescope shows galactic star formation is slowing
New star formations in spiral galaxies such as the Milky Way have declined five-fold in the last three billion light years, the first findings of the European Space Agency's Herschel telescope revealed on Thursday.
While scientists already knew that star formation was more prolific billions of light years ago, the Herschel telescope has for the first time been able to start measuring the rate of decline, scientist Steve Eales said at the launch.
"Three billion light years ago, galaxies were forming stars at ... five times the rate we know today," he told AFP at the agency's offices in Noordwijk in the western Netherlands.
Eales said the Herschel telescope's infrared technology allowed scientists to see galaxies, mainly spiral ones, that were previously hidden from scientists' view by cosmic dust clouds.
The telescope, launched a year ago, is the biggest ever sent into space, orbiting at a distance of 1.5 million kilometres (932,000 miles) from the Earth.
"We knew that 10 billion light years ago there were these galaxies that were forming stars really fast," he said.
"But previous telescopes could not actually see that many galaxies between now and 10 billion light years ago. We haven't been able to fill that gap until today.
"What Herschel has been able to do because of the wave length it is observing at, it can suddenly see lots of galaxies in the nearby universe, up to about to the last three or four billion light years. It can fill the gap in cosmic history," Eales said.
This suggested, he said, that "at some point stars will stop forming" altogether, unless solar conditions changed.
Scientists still did not know the reasons for the decline.
© 2010 AFP