Long streamers of gas glow in the Large Magellanic cloud, remnants of a supernova blast that destroyed a white dwarf in a Type 1a supernova. Its remnants are known as SNR 0454-67.2. Such explosions occur when a white dwarf sucks in enough material from a companion star to reach a critical mass, triggering a catastrophic core collapse, rebound and shock wave that blows the star apart. Its remnants are blasted into the surrounding space, including heavy elements that were cooked up in the detonation. Because Type 1a supernovas all occur in the same fashion, they shine with a known brightness, or luminosity, that can be used to determine their distance. Such supernovae are known as “standard candles” and they are critical to modern cosmology, helping astronomers measure changes in the acceleration of the universe’s expansion due to dark energy.
