NASA / SCIENCE PHOTO LIBRARY NASA / SCIENCE PHOTO LIBRARY
Supernova remnant. Coloured Chandra X-ray image of the supernova remnant G21.5-0.9. This remnant is thought to be 40,000 years old, and the central region is about 5 light years wide. Supernovae occur when a star's nuclear reactions can no longer support it against gravity and it collapses in on itself. Collapsing material rebounds off a newly-formed neutron star at the supernova's heart to form the expanding shells of gas. X-rays are produced by high-energy electrons moving in the neutron star's magnetic field lines. G21.5-0.9 lies 16,000 light years from Earth in the constellation Scutum. This image was made by the Advanced CCD Imaging Spectrometer (ACIS) in 1999.
Model release not required. Property release not required.