Astronomers may have finally seen a star become a black hole

This 1991 image shows a small portion of the Cygnus Loop supernova remnant. The formation shown here marks the outer edge of an expanding blast wave from a colossal stellar explosion that occurred about 15,000 years ago. The blast wave slams into clouds of interstellar gas, causing it to glow and revealing information about the composition of the gas.

A ring of glowing debris encircles the remains of supernova 1987A in the Large Magellanic Cloud galaxy. This cosmic pearl necklace is about 1.4 light-years in diameter and was probably shed by the star thousands of years ago as it began to collapse. The debris was heated to some 11,100 degrees Celsius by the blast wave when the star exploded. Supernova 1987A is expected to glow for decades to come.

A violent and fiery-looking mass of gas and dust glows within a supernova remnant. The object, called N 63A, is what is left of a massive star that exploded, throwing its gaseous layers out into an already turbulent region. N 63A lies within a star-forming region in the Large Magellanic Cloud, an irregular galaxy some 169,000 light-years away from the Milky Way.

This Hubble Space Telescope image offers an intimate view of supernova Cassiopeia A's frayed remains. This spherical object is the youngest supernova remnant found to date within the Milky Way. This image is a mosaic of 18 separate images taken by Hubble's Advanced Camera for Surveys (ACS).