Question: how big is the black hole

Emilia Arguello answered on 4 Nov 2024:

Black holes vary widely in size, depending on the amount of material they contain. All black holes have a feature called an “event horizon”, which is the part of the black hole with such strong gravitational pull that not even light can escape. The “sizes” of black holes can be described by the diameter of this event horizon.

Stellar-mass black holes form from the collapse of massive stars and typically have masses ranging from about 5 to 30 times that of our Sun (which is approximately 333,000 times the mass of our Earth!!). Their event horizons measure about 10 to 90 kilometers (6 to 55 miles) in diameter. Intermediate-mass black holes are still quite mysterious but are theorized to have masses between 100 and 100,000 Suns, with event horizons from hundreds to thousands of kilometers across. Supermassive black holes, like the one found in the center of our galaxy, can have masses of millions to billions of Suns and event horizon of millions of kilometers. Ultramassive black holes are found in some galaxy centers and can reach tens of billions of solar masses. These would have event horizons comparable in size to our entire Solar System.