By Ron Cowen
Astronomers have confirmed one of the weirdest properties of the universe: Some mysterious force is pushing galaxies apart at a faster and faster rate.
Researchers base their new evidence on the intensity of light from the most distant exploding star ever observed. The intrinsic brightness of this supernova, as well as those of a slew of others closer to Earth, suggests that gravity on the cosmic scale has reversed its familiar role. Instead of pulling objects together, it now pushes them apart. Cosmologists attribute this flip side of gravity to a substance that would pervade the universe and that they call dark energy.