This stunning false-colour picture shows off the many sides of the supernova remnant Cassiopeia A. Located light-years away, Cassiopeia A is the remnant of a once massive star that died in a violent supernova explosion 325 years ago.
This image is NGC 6543 known as the Cat's Eye Nebula as it appears to the Chandra X-Ray Observatory and Hubble Telescope. A planetary nebula is a phase of stellar evolution that the sun should experience several billion years from now, when i.
In August of 2007 astronomers located a gigantic hole in the universe. This empty space, stretching nearly a billion light-years across, is devoid of any matter. A radical and controversial theory proposes that it is a "Universe-in-mass Black hole"