News Astronomy

Variable quasar may help measure the cosmos

By Ron Cowen

- More than 2 years ago

A flickering cosmic mirage, recorded for the first time in X rays, promises to provide a new estimate of how rapidly the universe is expanding.

The gravity of a foreground galaxy splits X rays from the quasar RXJ011.4+551 into four images. Chartas, et al./NASA

A flare that lasted for some 2,000 seconds caused the intensity of light in image A2 to fluctuate.