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Could white holes actually exist? (www.space.com)

submitted 2 years ago by readbeanicecream@kbin.social to c/space@kbin.social

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White holes are mathematically possible, according to general relativity. But does that mean they're actually out there?

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[–] sparseMatrix@kbin.social 1 points 2 years ago* (last edited 2 years ago) (1 children)

@readbeanicecream

I'm no authority, but I love this stuff. I read Dr. Hawking's book "A Brief History of Time", and it was not problematic for me.

My takeaway is that a black hole is a sort of manifold. It would follow that if there is a way into it, and stuff going into it, the stuff must be coming out somewhere.

The question is where that stuff comes out, and in what form, and when, in it's local time frame.

I had always envisioned this hypothetical 'other side' as a white hole. It seems like, since we haven't observed any white holes, that the exits must be elsewhere.

[–] exscape@kbin.social 0 points 2 years ago (1 children)

I'm also no authority, but I strongly disagree that "it follows" that the stuff must be coming out.
We know that stuff enters black holes, and we know that they gain mass when it does. We think they shrink in mass over extreme periods of time, but other than that, I'm fairly sure we've never seen a black hole lose mass.

So if the mass comes out in a white hole, why does the black hole retain its mass?
I haven't read the book but I can't imagine he says, without strongly stating that it's very speculative, that such a thing could happen.

[–] sparseMatrix@kbin.social 0 points 2 years ago (1 children)

@exscape

@readbeanicecream

By definition, a manifold has a place where things go in, and other things come out. So yes, it does in fact logically follow. If its a manifold, then it logically follows that what goes in comes out.

You're saying we know a bunch of stuff I'm not certain we know.

My understanding is that by definition, the singularity has infinite mass and infinite gravity, so there is no way it can gain mass; because infinity + 1 = infinity. It's the very nature of infinities. You can have a number of infinities, but manipulating them arithmetically always yields infinity. 2 x infinity = infinity. 3 / infinity = infinity.

Like zero, it is more identity than number. 0 = nothing, infinity = everything.

So if you hope to have me follow your narrative, you're going to address this assertion concerning increasing the mass of black holes first.

[–] Sodis@feddit.de 0 points 2 years ago (1 children)

Black Holes do not have infinite mass. We pretty much know how heavy the are, because we can measure their gravitational influence on surrounding matter. They just have enough gravity, that light can't escape their gravitational pull. Infinite mass would also break a lot of fundamental physic laws, like conversation of energy.

3/infinity is 0. You probably meant infinity/3 is infinity.

[–] sparseMatrix@kbin.social 1 points 2 years ago* (last edited 2 years ago)

@Sodis

@readbeanicecream @exscape

According to my understanding, beyond the event horizon, gravity is infinite.

I am not a physicist - I'm a guy who read Prof. Hawking. Given the nature of llight vis a vis observation, inside the singularity, mass and gravity approach infinity.

Mass bends spacetime into gravity. Gravity bends light. Infinite mass > infinite gravity > stops light == singularity.

Note that things happening near the singularity are not the same as things that happen beyond the event horizon.