Cosmic Blast Creates Shock Wave 85 Times Larger Than Solar System

A mysterious cosmic blast in May created a shock wave that grew 85 times larger than the solar system within a couple weeks and has at least doubled in size since, according to new observations.

The May 8 explosion happened will outside the Milky Way galaxy, about 10 billion light-year away. A light-year is the distance light travels in a year.

The explosion was notices as a 15-second burst of gamma rays. Scientists have observed powerful gamma ray bursts for decades, but they still don’t know what causes them. Only recently have they determined that at least some bursts happen outside the galaxy.

The size estimate for the shock wave was determined from radio-wave emissions given off by particles swept up in the shock wave. Dale Frail of the National Radio Astronomy Observatory in Socorro, N.M., and colleagues there and elsewhere report their observations in the Sept. 18 issue of the journal Nature.

Just after the explosion, the shock wave was expanding at very near the speed of light, Frail said. Since then it has slowed to around 85% of the speed of light, he said.