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.
The spiral galaxy NGC 5468 presents a face-on view as seen in this image from the Hubble Space Telescope, giving astronomers the opportunity to observe multiple supernova blasts. Image: ESA/Hubble & NASA, W. Li et al.