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Detailed analysis of a star’s orbit near supermassive black hole

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Re: Detailed analysis of a star’s orbit near supermassive black hole

#21

This is a weird title given the content of the article, which is that researchers observing a supermassive black hole got a result completely consistent with general relativity.

The title was the best clickbait that they could get, based on an offhand comment that the theory has to break down inside the black hole.

But if the title was, "General Relativity succeeds again", who would have read the article?

Re: Detailed analysis of a star’s orbit near supermassive black hole

#22
post #7

Earlier quoted context omitted.

No the finding is that they tested GR near a boundary, where you might expect find issues, and found that it held up. The title and the comment Ghez makes about the interior of a black hole are a bit misleading. As far as interiors of black holes, I can only guess that she's pointing out (a) that we can't directly observe anything past the event horizon and (b) GR doesn't really make claims about what's going on in t…

In the classical black hole model anything that crosses the event horizon only has a limited time before they hit the singularity. Even for particularly big black holes this wouldn't take all that long. I find it a bit tricky to say if you wouldn't encounter all the stuff that fell in before you though. I've always had trouble reconciling the fact that you won't see stuff enter the event horizon until you're close to…

It gets crazier still.

Nothing ever gets into a black hole! If something is falling into a black hole, you can wait a million years and then rescue it. Or a billion. You see, time slows in a gravitational well. The bigger the gravitational well, the more it slows. From our point of view outside, time literally stops at the event horizon.

Re: Detailed analysis of a star’s orbit near supermassive black hole

#23
That's science. Hate this headline. Basically, every theory is "standing for now."

We get understanding, that leads to questions, which leads to greater understanding...

A predictive theory, finally found to not be predictive, is still valid for all it can predict. Our understanding improves in some way, or technology does, and we advance all of those things, being able to predict to greater detail and depth.

Re: Detailed analysis of a star’s orbit near supermassive black hole

#24
post #21

This is a weird title given the content of the article, which is that researchers observing a supermassive black hole got a result completely consistent with general relativity.

The title was the best clickbait that they could get, based on an offhand comment that the theory has to break down inside the black hole. But if the title was, "General Relativity succeeds again", who would have read the article?

It's unfortunate some people think having their article read is a priority. Perhaps we need a browser plugin where people can rank the accuracy of titles from various outlets so the user can decide if an article is likely to waste their time.

Re: Detailed analysis of a star’s orbit near supermassive black hole

#25

Does this mean it's at least possible that space and time aren't linked in the way we think? That General Relativity only makes it appear so?

Does this mean it's at least possible that space and time aren't linked in the way we think?

Technically, we (loaded term) don't really think of anything as per se. General Relativity and the standard model - or Quantum Field Theory more specifically - are just that: Models. They are very good models, but not complete ones (Or unified, assuming they will be at some point)

Re: Detailed analysis of a star’s orbit near supermassive black hole

#27
post #24
post #21

Earlier quoted context omitted.

The title was the best clickbait that they could get, based on an offhand comment that the theory has to break down inside the black hole. But if the title was, "General Relativity succeeds again", who would have read the article?

It's unfortunate some people think having their article read is a priority. Perhaps we need a browser plugin where people can rank the accuracy of titles from various outlets so the user can decide if an article is likely to waste their time.

I would gladly install a Chrome plugin that would report a ‘clickbaity-ness’ value for articles/URLs.

Re: Detailed analysis of a star’s orbit near supermassive black hole

#28
post #24
post #21

Earlier quoted context omitted.

The title was the best clickbait that they could get, based on an offhand comment that the theory has to break down inside the black hole. But if the title was, "General Relativity succeeds again", who would have read the article?

It's unfortunate some people think having their article read is a priority. Perhaps we need a browser plugin where people can rank the accuracy of titles from various outlets so the user can decide if an article is likely to waste their time.

That's a good idea, it's basically why everyone checks the comment section first.

Re: Detailed analysis of a star’s orbit near supermassive black hole

#29
post #22

Earlier quoted context omitted.

In the classical black hole model anything that crosses the event horizon only has a limited time before they hit the singularity. Even for particularly big black holes this wouldn't take all that long. I find it a bit tricky to say if you wouldn't encounter all the stuff that fell in before you though. I've always had trouble reconciling the fact that you won't see stuff enter the event horizon until you're close to…

It gets crazier still. Nothing ever gets into a black hole! If something is falling into a black hole, you can wait a million years and then rescue it. Or a billion. You see, time slows in a gravitational well. The bigger the gravitational well, the more it slows. From our point of view outside, time literally stops at the event horizon.

Consider a simple linear function f(x)=ax. It maps the whole real axis bijectively to itself so long as “a” is not 0. However if a=0 everything collapses into the origin.

The math that wraps some infinite process inside can be counterintuitive even as it makes things easier to compute. However it is not clear if the physical picture that involves singularity is real or just idealized approximation.

Re: Detailed analysis of a star’s orbit near supermassive black hole

#30
post #7

Does this mean it's at least possible that space and time aren't linked in the way we think? That General Relativity only makes it appear so?

No the finding is that they tested GR near a boundary, where you might expect find issues, and found that it held up. The title and the comment Ghez makes about the interior of a black hole are a bit misleading. As far as interiors of black holes, I can only guess that she's pointing out (a) that we can't directly observe anything past the event horizon and (b) GR doesn't really make claims about what's going on in t…

> From what I've read, it's thought that inside the event horizon, black holes are almost totally empty until you get to the singularity (or torus if it's spinning) at the center.

I can see how this could maybe be true for a black hole that never has anything fall into it after yourself, but for regular black holes that have things falling in regularly I think the situation would be pretty different. As you get closer to the event horizon, the rest of the universe appears to speed up. This means that as you get closer, the rate of objects / energy coming into the black hole past you and sometimes colliding into you will increase. You can imagine that at some point near the event horizon, every second, 100 years will pass for the rest of the universe, and 100 years worth of debris and light will enter into the black hole, some of it colliding with you. As soon as you reach the event horizon, an infinite amount of time's worth of debris and light will enter into the black hole, some of it colliding with you. From inside the black hole, it must look like everything that has ever fallen into the black hole in the history of the universe has fallen into it at the same instant. (And then I'm not entirely sure how black hole evaporation fits into this. I'd expect the perspective of someone going into a black hole must look like you immediately collide with everything that ever has and ever will fall into the black hole, and then instantly everything is obliterated into Hawking radiation.)

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