Shocked by Supernova 1987a . ... Credit Copyright: P. Garnavich ( Harvard CfA), WFPC2 , HST , NASA Explanation: Eleven years ago the brightest supernova of modern times was recorded. ... The onset of this collision is shown by the arrow in the above picture as the yellow spot on the interior of the ring. ... As the supernova blast wave moves out, it shock-heats any gas it encounters, causing it to glow. ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...