The-Black-Widow-Pulsar-1-620x802

The “Black Widow” pulsar is moving through the galaxy at a speed of almost a million kilometers per hour. A bow shock wave due to this motion is visible to optical telescopes, shown in this image as the greenish crescent shape. The pressure behind the bow shock creates a second shock wave that sweeps the cloud of high-energy particles back from the pulsar to form the cocoon.

Read more: http://wordlesstech.com/2011/10/29/the-black-widow-pulsar/