Supernova explosions occur when massive stars run out of nuclear fuel, collapse and explode in titanic blasts visible across the cosmos. They also can be triggered when a white dwarf in a binary star system siphons off enough mass from a companion to ignite runaway nuclear fusion in its core to begin the supernova process. Both types of supernovae have been spotted in a galaxy known as NGC 5468, a spectacular face-on spiral whose orientation makes it easier to spot such exploding stars. Over the past two decades, NGC 5468, located some 130 million light years from Earth in the constellation Virgo, has hosted at least five supernovae: SN 1999cp, SN 2002cr, SN2002ed, SN2005P, and SN2018dfg.
Several thousand years ago, a star some 160,000 light-years away from us exploded, scattering stellar shrapnel across the sky. The aftermath of this Type Ia supernova is shown here in this striking image from the NASA/ESA Hubble Space Telescope. The exploding star was a white dwarf located in the Large Magellanic Cloud, a close neighbouring galaxy.