Chandra X-ray Image of SN 1970G
Chandra's image of SN 1970G shows X-rays from a supernova that was observed to occur 35 years ago. Before a massive star explodes as a supernova, it loses gas in a stellar wind that creates a circumstellar gas shell around the star. The explosion generates shock waves that rush through this gas and heat it to millions of degrees. The X-rays from SN 1970G are likely due to this process. Astronomers estimate that in another 20 to 60 years the shock waves will have traversed the shell and encountered the interstellar medium. At this time SN 1970G will make the transition to the supernova remnant phase of its evolution.
Scale: Image is 5.5 arcmin across
(Credit: NASA/CXC/GFSC/S.Immler & K.Kuntz)

NOAO Optical Image of SN 1970G
This optical image of M101 (aka the Pinwheel Galaxy, or NGC 5457) was taken by NOAO's Kitt Peak National Observatory (KPNO) 0.9-meter telescope. M101, a spiral galaxy about 22 million light years away in the constellation Ursa Major, is similar to our own Galaxy, the Milky Way.
(Credit: NOAO/AURA/NSF/G.Jacoby, B.Bohannan & M.Hanna)