Astrophys. J. 682, 724–736 (2008)

A survey of exploding stars shows that the farther away they are, the slower they seem to blow apart, as predicted on the basis of general relativity. The supernovae studied are known as type 1a supernovae, and are important for gauging the strength of dark energy — a mysterious force that seems to be pushing the Universe apart. These findings reassure astronomers that the far away supernovae behave like those nearby.

Stéphane Blondin at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and his colleagues studied thirteen supernovae between 3.6 and 7.5 billion light years from Earth. The group compared several spectra from the more distant supernovae with those of nearer ones and found that the more distant explosions took longer to unfold.