Huge galaxy cluster is wrapped in a cocoon 20 million light-years wide, NASA space telescope finds

The galactic cluster PLCK G287.0+32.9 which the Chandra X-ray telescope (inset) has discovered is surrounded by a cocoon 20 million light years wide!.

Using NASA's Chandra X-ray space telescope, astronomers have discovered that a galaxy cluster is wrapped in an envelope of energized particles that's 20 million light-years wide. The discovery raises the question of how cosmic particles remain energized over a long period of time.

The largest such cloud ever seen, this cosmic envelope surrounds the massive galaxy cluster PLCK G287.0+32.9, which is located 5 billion light-years from Earth.