Astronomers discover heaviest black hole to date.
The black hole in the nearby galaxy M87 weighs in at 6.6 billion suns, making it the local universe’s heavyweight champ.
The behemoth’s bulk, plus the fact that it lives just 50 million light-years away, makes M87 the best candidate for future efforts to take a direct image of a black hole’s event horizon for the first time.
At nearly 6 trillion times the mass of the sun, M87 is the most massive galaxy in the Milky Way’s cosmic neighborhood. Astronomers expected it to host a correspondingly huge black hole, but the most commonly accepted estimates — based on measurements from the Hubble Space Telescope — found the black hole weighed just 3 billion solar masses, give or take a billion.
To pin down the monstrous black hole’s mass, Gebhardt and his colleagues used the Gemini North telescope atop Mauna Kea in Hawaii to measure the speeds of stars zipping past the galactic center.
The closer stars got to the center of the galaxy, the faster they moved, indicating that a huge hunk of mass lurks at the center to speed stars up. Gebhardt and colleagues used supercomputer models to calculate the black hole’s true heft: 6.6 billion suns, give or take 0.25 billion. For comparison, the black hole at the center of the Milky Way is a mere 4 million solar masses.
Most of that mass probably came from gas and stars the black hole has devoured over the millennia. But the trajectories of the stars orbiting the black hole suggest that the solo monster that exists today is the product of two smaller black holes merging into one.
Big black holes also have big event horizons, the point at which a black hole’s gravity is so great even light can’t escape. The black hole in M87’s event horizon is about 12 billion miles across, three times the size of Pluto’s orbit.
That extensive event horizon would cast a dark shadow on the galactic dust behind it. Future observations with a worldwide network of telescopes looking at wavelengths of light smaller than a millimeter could potentially take a picture of that shadow, proving once and for all that black holes exist.
This black hole is 6.6 billion times the mass of the sun. This solar system could swallow this solar system with no difficulty.