For immediate release Ref. This extraordinary finding has been named by the journal 'Science' as Breakthrough of the Year for 1998. These supernovae all have the same intrinsic brightness. This means that their apparent brightness as observed from Earth reveals their distance. By comparing the distance of these exploding stars with the redshifts of their host galaxies, researchers can calculate how fast the universe was expanding at different times in its history.
Good results depend upon observing many type Ia supernovae, both near and far.
The Supernova Cosmology Project has fully analysed the first 42 out of more than 80 supernovae it has discovered, and more analysis is in progress. Type Ia supernovae are rare. In a typical galaxy they may occur only two or three times in a thousand years. And to be useful they must be detected within a week or two of the explosion, while the supernova is still increasing in brightness. Today's award from 'Science' comes after over a decade of hard work by a large team of astronomers at Cambridge and Berkeley.