Vela Supernova Remnant in Optical Credit: Photograph made from plates taken with the UK Schmidt Telescope [ http://www.roe.ac.u ]. Color photography by David Malin. Copyright: Anglo-Australian Telescope Board [ http://www.aao.gov. ]
Vela Supernova Remnant in Optical Credit: Photograph made from plates taken with the UK Schmidt Telescope [ http://www.roe.ac.uk/ukstu/ukst.html ]. Color photography by David Malin. Copyright: Anglo-Australian Telescope Board [ http://www.aao.gov.au/images.html ]
About 11,000 years ago a star in the constellation of Vela [ http://galileo.gmu.edu/constellation/VEL.html ] exploded. This bright supernova [ http://antwrp.gsfc.nasa.gov/apod/lib/supernova.html ] may have been visible to the first human farmers. Today the Vela supernova remnant [ http://www.seds.org/billa/twn/velax.html ] marks the position of a relatively close and recent explosion in our Galaxy [ http://antwrp.gsfc.nasa.gov/apod/lib/milky_way.html ]. A roughly spherical, expanding shock wave is visible in X-rays [ http://antwrp.gsfc.nasa.gov/apod/ap960611.html ]. In the above optical photograph, the upper left corner of the spherical blast wave is shown in detail. As gas flies away from the detonated star [ http://lheawww.gsfc.nasa.gov/users/jonathan/outreach_pages/supernova.html ], it reacts with the interstellar medium [ http://www-dapnia.cea.fr/Phys/Sap/Report/interstellar_medium.html ], knocking away closely held electrons from even heavy elements [ http://pdg.lbl.gov/cpep/adventure.html ]. When the electrons recombine with these atoms [ http://adsabs.harvard.edu/cgi-bin/nph-article_query?bibcode=1995ApJ%2E%2E%2E440%2E%2E227J&page=1&plate_select=NO&type=GIF ], light in many different colors and energy bands [ http://heasarc.gsfc.nasa.gov/docs/learning_center/basic/emspectrum.html ] is produced.