Calculating the event horizon of black holes.

In summary, the conversation discusses the possibility of calculating the event horizon of a non-rotating black hole and the equations involved in the calculation. The speaker suggests using the Schwarzschild equation to determine the radius of the horizon, which is also referred to as the radius of the black hole. The conversation ends with a clarification that the radius being calculated is not the actual radius of the black hole, but rather the radius of its horizon.
  • #1
William Henley
Hello, I remember hearing somewhere that it is possible to calculate the event horizon, I was just wondering if this is possible and what equations are used to calculate it.
 
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  • #2
"hearing somewhere" is not a very solid reference, although it happens to be correct in this case. It is rather trivial for a non-rotating black hole. Have you done any research at all?
 
  • #3
William Henley said:
Hello, I remember hearing somewhere that it is possible to calculate the event horizon, I was just wondering if this is possible and what equations are used to calculate it.

I would give you a suggestion, as it very simple to do and quite satisfying... Think of a satellite around the Earth and find its escape velocity, you should get something very simple, function of the mass of the Earth and the distance to the satellite. Then equalize that velocity with the velocity of light, solve for the distance and voila, you get the radius of the horizon (or the Schwarzschild radius, as it is called)
Virgil.
 
  • #4
phinds said:
"hearing somewhere" is not a very solid reference, although it happens to be correct in this case. It is rather trivial for a non-rotating black hole. Have you done any research at all?
Yeah I have, and I found that the Schwarzschild equation can be used to calculate the radius of the black hole. But I was wondering if someone could explain how to use the equation.
 
  • #5
William Henley said:
Yeah I have, and I found that the Schwarzschild equation can be used to calculate the radius of the black hole. But I was wondering if someone could explain how to use the equation.

Just an observation, it is not the radius of the black hole, but the radius of the horizon of the black hole.
 
  • #6
virgil1612 said:
Just an observation, it is not the radius of the black hole, but the radius of the horizon of the black hole.
Which is usually called "the radius of the black hole" since a black hole does not have any other radius.
 

1. What is the event horizon of a black hole?

The event horizon of a black hole is a boundary in space around the black hole from which nothing, including light, can escape. It marks the point of no return for anything that gets too close to the black hole.

2. How is the event horizon of a black hole calculated?

The event horizon of a black hole is calculated using the Schwarzschild radius, which is determined by the mass of the black hole. The formula for calculating the Schwarzschild radius is 2GM/c^2, where G is the gravitational constant, M is the mass of the black hole, and c is the speed of light.

3. Can the event horizon of a black hole change?

Yes, the event horizon of a black hole can change over time. As matter and energy fall into the black hole, the mass of the black hole increases, and thus the event horizon also expands. However, once something crosses the event horizon, it is impossible for it to escape.

4. What happens at the event horizon of a black hole?

At the event horizon of a black hole, the gravitational pull is so strong that even light cannot escape. This causes time and space to become distorted, and the laws of physics as we know them break down. Anything that crosses the event horizon is pulled into the black hole and is subjected to extreme gravitational forces.

5. Is there a way to observe the event horizon of a black hole?

Currently, there is no way to directly observe the event horizon of a black hole since nothing can escape from it. However, scientists can indirectly observe the effects of the event horizon, such as the bending of light and the emission of radiation from the accretion disk around the black hole.

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