The Large Binocular Telescope (LBT for short) in Arizona was scanning the Fireworks Galaxy 22 million light years away looking for supernova candidates. [The galaxy is known for having large numbers of supernova explosions.] They examined the star named N6946-BH1 – a star 25 times more massive than our Sun. Stars that size usually end in a supernova explosion – leaving behind a neutron star or a black hole. In 2009, the star shot up in brightness to become over 1 million times more luminous than our sun for several months. The expectation was that it was about to supernova. But it didn’t. It just seemed to vanish, as seen in this image from 2015. The star was no longer there. The researchers eventually concluded that the star must have become a black hole – without a supernova. It has been estimated that up to 30% of all massive stars that form black holes form them this way with the remaining 70% taking the supernova path.