Tag: reappearing

A cosmic camera hog is helping astronomers figure out the rate of the universe’s expansion.

Images of the supernova Refsdal have popped up multiple times in the constellation Leo, thanks to light from the stellar explosion wending its way through the gravitational field of a cluster of galaxies. Analyzing delays between Refsdal’s appearances provides a new measurement of the Hubble constant, researchers report online May 11 in Science. That constant describes how quickly galaxies are flying away from each