Second-biggest black hole in the Milky Way found

Enlarge / The star's orbit, shown here in light, is influenced by the far more massive black hole, indicated by the red orbit. (credit: ESO/L. Calçada)

As far as black holes go, there are two categories: supermassive ones that live at the center of the galaxies (and we're unsure about how they got there) and stellar mass ones that formed through the supernovae that end the lives of massive stars.

Prior to the advent of gravitational wave detectors, the heaviest stellar-mass...