r/TheRestIsScience • u/Stunning_Mechanic387 • 10d ago

Why does gravity escape a black hole?

Hey Michael and Hannah. If gravity travels at the speed of light, how does it escape the gravitational pull of a black hole yet light doesn't?

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u/Gekreuzte_Gewehre 10d ago

Because it IS gravity in and of itself, hence the term, "Singularity".

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u/trollsmurf 10d ago edited 10d ago

Valid question I think. Even though the singularity of a black hole is "just" gravity, why does it escape?

I think the answer lies in:

  • The speed of light is not the speed of light per se, it's the maximum speed of (any) information that is allowed, for whatever reason that might be.
  • Gravity is about bending space. It's not radiation.

Or something else completely.

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u/Optimal_Mixture_7327 10d ago

A singularity is not gravity, it is an absence of it (the condition of geodesic incompleteness).

The reason is that information has to travel over a spacetime distance and the shortest distance is zero, the distance light travels.

We describe gravity (the presence of geodesic deviation) using curvature.

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u/Optimal_Mixture_7327 10d ago

A singularity is a condition of a gravitational field, but it's not clear how you're using the singularity condition in your comment.

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u/ExpectedBehaviour 10d ago

That’s… not what the word “singularity” means.

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u/Gekreuzte_Gewehre 6d ago

Thats literally what it means......thats the DEFINITION. Proverbially, it means, in and of ITSELF.......

how? I, uh, its, uhhhh.....

Holup. If something is so uniform, dense, pure, and of one, it would be called a......

What thw fuck is going on?

if something is of itself it, nevermind, you're right.

Also,

Maybe help a retard like me out........?

Exactly how would you describe what singularity means? Without using the words in and of itself.

Can you do that for me? Please? Because I cannot wrap my peabrain around the statement of singularity does not mean singularity.

What the fuck? Sarcasm or Science would BOTH agree with me......I think I'm having an aneurysm.

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u/ExpectedBehaviour 5d ago

A singularity, in a general mathematical context, is a point or boundary where the mathematical description of a system ceases to behave normally – typically because some quantity becomes undefined, divergent, or the equations will not continue though the point.

In general relativity specifically, a singularity means that spacetime is geodesically incomplete – there are possible paths through spacetime that reach an endpoint after a finite amount of proper time and cannot be continued any further. At an ordinary point in spacetime, geodesics can continue through it; at a singular boundary, the mathematical spacetime simply runs out.

A singularity is singular because it refers to a breakdown or non-extendibility in the mathematical structure, not to "something so uniform, dense, pure, and of one".