https://motherboard.vice.com/en_us/article/j5zwvk/astronomers-may-have-seen-a-star-turn-into-a-black-hole-for-the-first-time

On June 16, 2018, astronomers around the world witnessed a cosmic flash unlike anything they’d ever seen before. Now, in a forthcoming paper to be published in the Astrophysical Journal, an international team of 45 scientists argue that what they saw that day was likely the exact moment a star collapsed into a black hole. If they’re right, it would be the first time that this transition was ever witnessed by human scientists.

When a star runs out of nuclear fuel, some of its mass flows into its core, which eventually gets so dense that it collapses from its own gravitational force. This creates an explosion known as a supernova, which astronomers on Earth can detect as a bright flash of light.