Astronomy Picture of the Day

Explanation: Yesterday's image highlighted reflective rings of light emitted by a supernova explosion. Today's pictures, taken over a year apart, highlight how these echoes are seen to move over time. Visible on the left of each picture is part of a reflective ring, an existing dust cloud momentarily illuminated by the light of Supernova 1987A. Note how the nebulosity reflecting the most light occurs further to the left in the lower photograph. If you look closely, you can see the actual location of SN 1987A itself on the right of each photograph: it appears in the centre of a small yellowish ring. The apparent motion and brightness of these echoes help astronomers understand the abundance and distribution of interstellar nebulae in the LMC galaxy, where the stellar explosion occurred.