So I've had a question about stellar mass black holes that I can't seem to be able to get answered (the question was deleted for /r/askscience). How does a stellar mass black hole actually form a singularity given the fact that there's gravitational time dilation? Wouldn't the heart of a black hole slow down relative to an outside observer as mass is added to it so that you never actually reach infinite density? It s…
I reached the same conclusion years ago, and the answer is very simple (and controversial): Black holes do not exist. If they existed they could exist, but it's impossible for them to form. I've asked many many physicists this very same question, and none could answer me (or I've gotten hand-wavy non answers). It's like no one wants to be the first to declare this well accepted thing as non-existing. The black holes…
The strange fate of a person falling into a black hole
121–130 of 164 posts
Re: The strange fate of a person falling into a black hole
#122Earlier quoted context omitted.
I reached the same conclusion years ago, and the answer is very simple (and controversial): Black holes do not exist. If they existed they could exist, but it's impossible for them to form. I've asked many many physicists this very same question, and none could answer me (or I've gotten hand-wavy non answers). It's like no one wants to be the first to declare this well accepted thing as non-existing. The black holes…
Not true: http://motls.blogspot.co.at/2008/11/why-can-anything-ever-fa...
That explained nothing whatsoever.
I'll even quote:
"At some moment, the radius of the star drops below the Schwarzschild radius - that's where the yellow and orange lines intersect. At this moment, the star is pretty much doomed. Right now I am not sure whether one can generally prove that the event horizon becomes inevitable at this point but I am sure that it is going to be there in a moment according to the picture above which is surely realistic."
He simply skips right past the impossible point: "the radius of the star drops below the Schwarzschild radius". It will take that Sun an infinite amount of time to do that. Any conclusions you draw after that point are unscientific.
He draws all sort of conclusions from the diagram, without ever showing that his diagram is actually true.
There was some talk of how to be a stationary observer near the black hole you must keep accelerating, but a: I fail to see how that explains the infinite time, and b: who said I have to be near the black hole to look at it?
Re: The strange fate of a person falling into a black hole
#123Earlier quoted context omitted.
I reached the same conclusion years ago, and the answer is very simple (and controversial): Black holes do not exist. If they existed they could exist, but it's impossible for them to form. I've asked many many physicists this very same question, and none could answer me (or I've gotten hand-wavy non answers). It's like no one wants to be the first to declare this well accepted thing as non-existing. The black holes…
Astrophysicists aren't insisting that black holes have singularities on the insides (just speculating that there are objects that are well described as a gravity well with an event horizon).
Astrophysicists do not see an event horizon. All they see is massive gravity.
Re: The strange fate of a person falling into a black hole
#124So I've had a question about stellar mass black holes that I can't seem to be able to get answered (the question was deleted for /r/askscience). How does a stellar mass black hole actually form a singularity given the fact that there's gravitational time dilation? Wouldn't the heart of a black hole slow down relative to an outside observer as mass is added to it so that you never actually reach infinite density? It s…
Matter gets added to the hole even though an outsider never sees it fall in. This should lead to the increase of the schwarzchild radius . It has been proved by Penrose that once the mass falls inside its horizon, the singularity is inevitably formed in its center: http://www.quantum-gravitation.de/media/2d2cde3ec9c38fffffff...
Re: The strange fate of a person falling into a black hole
#125Earlier quoted context omitted.
Astrophysicists aren't insisting that black holes have singularities on the insides (just speculating that there are objects that are well described as a gravity well with an event horizon).
Astrophysicists do not see an event horizon. All they see is massive gravity.
Yeah, that's why I said "speculating", and they will also say that they are speculating, if you ask them to be careful.
(edited for clarity)
Re: The strange fate of a person falling into a black hole
#126Earlier quoted context omitted.
> There might even be a sort of Zeno's Paradox inside, where once you cross the event horizon, there's another event horizon beyond that, such that anything that much closer to the singularity than you are can never communicate with you, in the same way that you can never communicate with the universe outside the first event horizon. Isn't every step in from the event horizon effectively an event horizon? If all the…
I don't think that's quite what they meant by that. In silly "outside universe coordinates", inside the black hole you can define a "minimum inwards speed" as a function of distance from the singularity. This is how fast a photon will go towards the singularity if fired directly away from it. It's zero at the event horizon, and it increases as you go in. Now, what (I think) logfromblammo was saying was, "If I'm at th…
The distance between fallers determines the energy requirements for communication. The lower person will also experience slower time than the higher.
The analogy is as follows:
Two BASE jumpers leap from the top of an infinitely tall radio mast in a vacuum, one after the other. They are in free-fall, so do not directly experience the effects of gravity, but the increase in the gravitational field as the distance to the singularity decreases will be detectable as a pseudoforce in that reference frame.
The first jumper writes a note on a baseball and throws it at the second. The second also writes a note on a baseball and throws it at the first.
The concern for the first jumper is not whether the baseball can be thrown back to the top of the radio mast, but whether it can be thrown hard enough and accurately enough for the second to ever reach it. The concern for the second is whether the first can catch his ball without exploding like a paper sack full of wet spaghetti.
The other thing to consider is that both fallers will "see" multiple images of the other, and of themselves, because there is a direct light path, the light path that twists around once, the light path that twists around twice, and so on. Images further away will be lower, slower, and older. If you aimed correctly, you could send messages to your older self, but I'm not entirely certain if your older self could reply.
Re: The strange fate of a person falling into a black hole
#127Earlier quoted context omitted.
Indeed you won't ever be able to ever see something fall into it, but when you get down to it that's just because the light will take an infinitely long time to reach you. There are coordinate systems that are able to describe stuff falling past the event horizon in finite time, you just won't be able to see this happening until you fall into it yourself.
My question isn't along the lines of how visible it is to an outside observer, it's more of how can a singularity itself form? It seems like you can't reach infinite density in finite time given gravitational time dilation.
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Re: The strange fate of a person falling into a black hole
#128I guess I've always misunderstood blackholes. I was under the impression that they were simply a vacuum created as a by product of the every expanding "space". Sure they are sucking things up and growing, but space is always expanding.
Re: The strange fate of a person falling into a black hole
#129Earlier quoted context omitted.
Indeed you won't ever be able to ever see something fall into it, but when you get down to it that's just because the light will take an infinitely long time to reach you. There are coordinate systems that are able to describe stuff falling past the event horizon in finite time, you just won't be able to see this happening until you fall into it yourself.
My question isn't along the lines of how visible it is to an outside observer, it's more of how can a singularity itself form? It seems like you can't reach infinite density in finite time given gravitational time dilation.
It takes a finite amount of proper time (time experienced by the particle) to reach the singularity.
Re: The strange fate of a person falling into a black hole
#130So I've had a question about stellar mass black holes that I can't seem to be able to get answered (the question was deleted for /r/askscience). How does a stellar mass black hole actually form a singularity given the fact that there's gravitational time dilation? Wouldn't the heart of a black hole slow down relative to an outside observer as mass is added to it so that you never actually reach infinite density? It s…
I reached the same conclusion years ago, and the answer is very simple (and controversial): Black holes do not exist. If they existed they could exist, but it's impossible for them to form. I've asked many many physicists this very same question, and none could answer me (or I've gotten hand-wavy non answers). It's like no one wants to be the first to declare this well accepted thing as non-existing. The black holes…
In your model you get a skin forming around the event horizon. However, stuff would still be attracted to that object. This increased mass would increases the size of the event horizon. So, your hypothetical border would need to expand as matter accumulates. One of the odd things about black holes is there density decreases as their size increases. At really large scales even the 'vacuum' between galaxies is dense enough to form a black hole in a static universe.
PS: In reality black holes are molded by the full general relativity equation which most physicists don't actually understand. Much like how most programmers don't understand how GPU drivers work in detail.