NASA’s Hubble Revisits Crab Nebula to Track 25 Years of Expansion

In the year 1054, careful observers of the stars noted a new light in the sky, which was so bright it could be seen during the day for 23 days, and remained visible in the night sky for more than a year afterward. It was a supernova, a massive star exploding 6,500 light-years away. The remnant of the supernova was first seen through telescopes in the 1700s. It was eventually, and somewhat puzzlingly, nicknamed the Crab Nebula, likely a result of leggy-looking filaments extending from a central mass as seen through early telescopes.

In the mid-twentieth century, Edwin Hubble was one of several astronomers who connected the Crab to Chinese astronomical records. On the cusp of a new millennium, the telescope named for Hubble captured an intricately detailed portrait of the full supernova remnant, and 25 years later it has turned again to the ancient site to track the nebula's expansion and ongoing evolution.