M82: Starburst Galaxy with a Superwind . ... In fact , through ensuing supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving a prodigious outflow of material. ... Perched about 35,000 light-years above the galaxy at the upper left, the cap appears to be galactic halo material ionized by the superwind shock or intense ultraviolet radiation from the young, massive stars in the galaxy's core. ... NASA Web Site Statements, Warnings, and Disclaimers . ...