Friday, October 22, 2010

Alternative yardstick to measure the universe

Astronomers have long relied on stellar explosions called Type Ia supernovae to measure the scale of the cosmos. A second class of supernovae may now be put to the same use, providing an independent check on measurements that were first used more than a decade ago to discover the accelerating expansion of the Universe. A growing number of researchers are working on the idea that some Type II supernovae — which are caused by the gravitational collapse of giant stars with iron cores — may have a role as gauges of cosmic distance. "We're at the stage where it would be stupid to ignore alternative methods to Type Ia," says Dovi Poznanski of Berkeley Lab's Computational Research Division, who has re-analysed results that he says show the promise of the new cosmic measuring sticks. His most recent findings were published on 1 October in the Astrophysical Journal. More>