Unveiling the Universe's Largest Black Hole.

TON 618, a supermassive black hole, is the largest directly observed black hole with a confirmed mass, weighing roughly 40 billion solar masses and having a radius of over 1,000 astronomical units. It powers a quasar, one of the brightest objects in the universe, with the illuminating power of 140 trillion suns. The feeding rate of black holes sets the limit on their size, and there may be other ways to create even more massive black holes, such as from the direct collapse of large clumps of dark matter in the early universe.