Crab Nebula Still Expanding: A Millennium-Old Supernova Remnant in Motion

Hubble re-imaged the Crab Nebula to measure its ongoing expansion since SN 1054, finding filaments moving about 0.3 arcseconds per year (roughly 3.4 million mph) driven by energy from the central pulsar; the thousand-year-old remnant is not a static shell and new filament groups with similar emission were identified, linking the medieval guest star to a living, evolving nebula about 6,500 light-years away in Taurus.