Mach 1000 shock wave lights supernova remnant

When a star explodes as a supernova, the material blasted outward from the explosion still glows hundreds or thousands of years later, forming a picturesque supernova remnant. What powers such long-lived brilliance? In the case of Tycho's supernova remnant, astronomers have discovered that a reverse shock wave racing inward at Mach 1000 (1,000 times the speed of sound) is heating the remnant and causing it to emit X-ray light.

Fuente : http://www.eurekalert.org/pub_releases/2013-11/hcf...