Supernova Shock Wave Captivates Astronomers Fri. Combined optical and radio image of Galaxy M81.
Brightest part is the galaxy's nucleus.
Supernova SN1993J is below, detailed. A sequence of colorful images detailing a stellar explosion in another galaxy show a supernova's massive, morphing shock wave, providing scientists with a case study in the structure and evolution of the events. The images of SN1993J, discussed in the Jan. 7 issue of the journal Science , represent the first long-term supernova sequence ever obtained. Five years later the shock wave had slowed to less than half that speed as it fought increasing drag caused by particles in the interstellar medium. The last known supernovas in our own galaxy exploded in the 1700s.