Weighing the Black Hole in M87

Astronomers using the Gemini telescope have "weighed" the black hole at the centre of the M87 Galaxy.  They found it to be mass of 6.6 billion Suns, the largest ever measured for a black hole using a direct technique.

Using the Near-Infrared Field Spectrograph (NIFS) on Gemini, an 8-metre telescope in Hawaii, researchers measured the speed of stars orbiting the centre of the galaxy, and from this were able to calculate the mass of it's black hole...