V404 Cygni

On June 15, the Swift satellite caught the onset of a rare X-ray outburst from a stellar-mass black hole in the binary system V404 Cygni. In that system a stream of gas from a star much like the sun flows toward a 10 solar mass black hole. Instead of spiraling into the black hole, the gas accumulates in an accretion disk around it. Every couple of decades, the disk changes state, sending the gas rushing inward. The result is a new X-ray outburst.

[youtube https://www.youtube.com/watch?v=fCWteTkhd_A]

Video Credit: NASA