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What is the Equation for the Mass of a Black Hole?

-- Ava | May 22, 2024

Question:

Hello, my name is Ava Yarbrough. I’m 13 years old and was wondering what the specific equation of a black hole is and how would you solve it? Another question of mine is: why was the black hole theory rejected by Albert Einstein? I was just wondering if you had any guesses as to why.
Thank you

-- Ava

Answer:

If you can measure the velocity of an object that is orbiting around a black hole, you can use a measurement of the object’s orbital velocity (v) and the radius of its orbit (r) to calculate the mass of the central object (M) about which it is orbiting: M = r*v^2/G, where G is the gravitational constant. Regarding Einstein’s reservations about the existence of black holes, it is true that he initially found the concept so extreme that he questioned their very existence. Eventually, though, it was Einstein’s theory of relativity that provided the physical and mathematical support for their existence.

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