Supermassive Monsters

Stellar black holes form from dead stars and are typically 5-50 solar masses. But at the center of nearly every galaxy lurks a supermassive black hole millions to billions of times the Sun's mass. Our own Milky Way harbors Sagittarius A*, weighing in at 4 million solar masses.

Among the largest known black holes is TON 618, often estimated at more than 60 billion solar masses. Its event horizon would be wider than our entire solar system. Rankings of the single "largest known" black hole are uncertain, because the most massive candidates are distant and their masses depend on indirect measurements.