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.
With a view 100 times bigger than that of the Hubble Space Telescope, NASA’s Wide Field Infrared Survey Telescope (WFIRST) will aid researchers in their efforts to unravel the secrets of dark energy and dark matter, and explore the evolution of the cosmos. It also will discover new worlds outside our solar system and advance the search for worlds that could be suitable for life.
Around half of the star formation in the local universe arises from minor mergers between galaxies, according to data from the Sloan Digital Sky Survey. Disruptions to the shapes of spiral galaxies, caused by interactions with their smallest neighbours, points to increased star formation. Evidence suggests that minor galactic mergers are therefore important drivers of galaxy evolution.