The discussion centers on the fate of matter and debris once it crosses the event horizon of a black hole. Participants agree that once matter is swallowed, it is crushed into the singularity, contributing to the black hole's mass. The only known mechanism for a black hole to lose mass is through Hawking radiation, which is an extremely slow process. Additionally, concepts such as mass inflation and the Cauchy horizon are introduced, suggesting complex interactions within rotating and charged black holes.
PREREQUISITESAstronomers, astrophysicists, and students of theoretical physics interested in black hole mechanics and the fate of matter within extreme gravitational fields.
fair enough.Drakkith said:I'm not reading it that way.
nitsuj said:Is the distinction between "rest mass" and energy with respect to gravity relevant for a black hole? When I read a black hole is 20 million time more massive than our sun, does that exclude kinetic energy, pressure ect? I'd guess that value is derived from the observed gravitational effect of the black hole. I can't imagine the calculation includes an estimate of the radiation absorbed because "Oh that's just momentum, not mass. We want to know how massive it is."
nitsuj said:What's more, I'm sure if I read about hawking radiation...it will be about radiation...not ejection of matter (rest mass) from the within the black hole. And again it just seems pointless making a mass/energy distinction in this context of changes in gravity of a black hole...why not just call all of it energy?
AgentSmith said:We cannot know for sure, but presumably it is crushed into the singularity. Some do not think an actual singularity can exist, based on quantum mechanics, so the center of the black whole is the smallest meaningful volume, the Planck volume. Either way, the spacecraft is crunched out of existence.
Joseph Austin said:Yes, I understand that the spacecraft will be crunched , let's say it will disintegrate into its smallest parts ( Into atoms perhaps? ) But my questions means where do they go? If they were sucked in, it would be impossible for it to go back to event horizon right?
nitsuj said:The things go "elsewhere".
In the same sense of the "elsewhere" region of a light cone...simply a cheeky comment referring to the physical elusiveness...or physical insignificance to an observer (distant)Drakkith said:What do you mean? As far as I understand, matter does not go anywhere. It stays in the black hole, probably in an unknown form or state due to the extreme pressure.
Well, "hole" is not all THAT bad a description, since they take stuff out of normal spacetime like putting it into a deep holeSun E Man said:It's too bad that black holes got named as such. They are not holes at all, but the most condensed masses we know about as far from being a hole as anything can get. (That we know of so far.) Food for thought.
Nonsense. Where did you ever get that idea?If two of these masses got close enough to each other their gravitational pull would bring them together at some speed faster than light.
No, they would just merge. Possible there would be debris from one or both accretion disks but nothing from the BH's themselves.That would be a collision of such magnitude that you would think that they would break up and send debris and energy in many different directions. That would be a small bang comparable to "The Big Bang". Or would they just combine and have a new gravitational pull of x + y?
true that it is said and true that it is true.It is said that nothing can go faster than light.
No, I think perhaps YOU should think about it. Perhaps you are getting confused because of gravitational time dilation but I don't see how even that could lead you to the conclusion that anything travels faster than light.This is an untrue statement because light goes faster than it's own speed when it enters a (I don't like to use the term) black hole. Think about it.
Sean Carroll said:We will now use these ideas to verify that, although you can use the Penrose process to extract energy from the black hole (thereby decreasing M), you cannot violate the area theorem:The area of the event horizon is nondecreasing.
Sun E Man said:This is an untrue statement because light goes faster than it's own speed when it enters a (I don't like to use the term) black hole. Think about it.
Shyan said:People here said that the Penrose process can't decrease the mass of the BH. I don't want to argue but here is a quote from page 269 of Sean Carroll's SpaceTime and geometry:
Carroll(like some other sources) defines an irreducible mass by ##M_{irr}^2= \frac 1 2 (M^2+\sqrt{M^4-(\frac J G)^2}) ## ans says that it can not decrease, hence the name. But he doesn't state clearly whether M can decrease or not. But he says after you extract all the rotational energy of the BH, you'll have a Schwarzschild BH with mass ##M_{irr}##.Chronos said:Can anyone cite a rerference claiming the Penrose procees decreases the mass of a black hole.
there is a theory that they come out of a white hole.Joseph Austin said:I'm just wondering if a spacecraft or any kind of matter was swallowed by a black hole , where does the debris go? I know that it will disintegrate, but even the gravity in there is very strong will there be debris left? If there is, Will it go to other dimension or what?
Thanks,
Austin
No there isn't. Black holes that form from collapsing matter, can't have a white hole.Akhand said:there is a theory that they come out of a white hole.
Black holes are formed due the reason that they are acting as a hole in the universe and every hole has it's end that is white hole.Shyan said:No there isn't. Black holes that form from collapsing matter, can't have a white hole.
White holes arise when people maximally expand the manifold with the Schwarzschild metric. Then you see extra regions which one of those regions is called a white hole because of its properties. But the point is, in the case of a black hole formed from collapsing matter, that part of the manifold which we called white hole, doesn't correspond to any point of the spacetime any more because it resides in the part of spacetime containing star's materials which means we should use a different metric there.Akhand said:Black holes are formed due the reason that they are acting as a hole in the universe and every hole has it's end that is white hole.
Chronos said:Can anyone cite a rerference claiming the Penrose procees decreases the mass of a black hole.
No, it is not. Why do you think it is?Sun E Man said:The speed of gravity is faster than the speed of light or it is a constant force that seems like it is faster than the speed of light.
Can't understand your grammar. If the sun magically vanished, the Earth would continue on in its orbit for 8 more minutes and then start going in a straight line in whatever direction in was moving when the gravity stopped. Light and CHANGES in gravity, which both travel at the speed of light, take 8 minutes to get here from the sunEinstein hypothetically did an experiment in which if the Sun were to loose it's gravity in an instant, the planets would instantly swing out of there orbits. The Earth would already be out of it's orbit for 8.3 minutes + by the time the the sun light reached it that started when the sun lost it's gravity.
But it is NOTWith this thought in mind is what made me think that the two Black Holes whose gravitational pull is is faster than the speed of light
would combine accelerating them to something more than the speed of light. There would be nothing to slow them down as they would have already pulled any thing that was in there way on to them selves now just pulling on each other. I believe this would be especially true once that they came close enough so that their event horizons combined. phinds thank you for your reply and please reply again.
Chronos said:All observational evidence to date suggests the 'speed of gravity' is c. Please city any credible examples to the contrary.
Yes, it is called the "Big Bang"H G Kellogg said:Is it possible for a 'Black Hole' to reach a critical mass- such as in an exploding star?
This is nonsense. Was it meant as a joke?Ron Hessinger said:Yes, it is called the "Big Bang"