The M87 black hole image showed the best way to measure black hole masses
Its diameter suggests the black hole is 6.5 billion times the mass of the sun
![galaxy M87](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2019/04/041719_lg_bhmasses_feat.jpg?fit=860%2C460&ssl=1)
SUPERMASSIVE SOURCE The gases and stars in galaxy M87, shown in this composite image from the Chandra X-ray telescope and the Very Large Array, gave different numbers for the mass of the galaxy’s supermassive black hole.
N. Werner, E. Million et al/KIPAC/CXC/NASA, F. Owen/NSF/AUI/NRAO