# Thread: Do you think maybe the gravity of a black hole oscillates?

1. Maybe it sort of pulses, or increases and diminishes in some kind of pattern?

I'm just suggesting this possibility because it seems like it would be a way for matter to escape into the surrounding universe, or rather for energy to escape, which is basically the same thing.

If gravity is increasing and diminishing, that makes it possible for energy to be transfered just one way. If the timing of highs and lows are set right, an object orbiting the black hole could actually experience a net acceleration away from it in the course of a few trips around its orbit.

Of course, I can't really come up with any reason why the gravitational field would do this. I'm just suggesting that, if it did, that would be a way for it to overcome a lot of the black hole paradoxes.

2.

3. Originally Posted by kojax
Maybe it sort of pulses, or increases and diminishes in some kind of pattern?

I'm just suggesting this possibility because it seems like it would be a way for matter to escape into the surrounding universe, or rather for energy to escape, which is basically the same thing.

If gravity is increasing and diminishing, that makes it possible for energy to be transfered just one way. If the timing of highs and lows are set right, an object orbiting the black hole could actually experience a net acceleration away from it in the course of a few trips around its orbit.

Of course, I can't really come up with any reason why the gravitational field would do this. I'm just suggesting that, if it did, that would be a way for it to overcome a lot of the black hole paradoxes.
So gravity is directly related to the mass M of an object. For the gravitational pull of an object the mass would have to change also and allthough I hate repeating it (actually i don't hate it, I really love it ) there is something as conservation of mass and conservation of energy so how do you decrease the mass of a black hole?

4. I would think it's being pretty stable.

5. If the gravitational pull of a blackhole did increase and then decrease, wouldn't it allow some light to occasionally escape it's pull and appear to us to be some sort of intergalactic light house ?

6. I have seen a BBC program where it had a huge light beam in the very middle pointing to both sides of it. Then, the whole
image started shaking and I thought the TV set would slump each second, but didn't. Huha... me lucky one.

7. Originally Posted by Twaaannnggg
Originally Posted by kojax
Maybe it sort of pulses, or increases and diminishes in some kind of pattern?

I'm just suggesting this possibility because it seems like it would be a way for matter to escape into the surrounding universe, or rather for energy to escape, which is basically the same thing.

If gravity is increasing and diminishing, that makes it possible for energy to be transfered just one way. If the timing of highs and lows are set right, an object orbiting the black hole could actually experience a net acceleration away from it in the course of a few trips around its orbit.

Of course, I can't really come up with any reason why the gravitational field would do this. I'm just suggesting that, if it did, that would be a way for it to overcome a lot of the black hole paradoxes.
So gravity is directly related to the mass M of an object. For the gravitational pull of an object the mass would have to change also and allthough I hate repeating it (actually i don't hate it, I really love it ) there is something as conservation of mass and conservation of energy so how do you decrease the mass of a black hole?
I'm just saying maybe a black hole is different from the rest of observable matter. Gallilean rules of velocity and momentum broke up a bit at extreme velocities. Maybe the currently accepted gravitational model breaks up at extreme densities.

In fact, I'm kind of suggesting that the two models would break up in the same way.

Originally Posted by Cat1981
If the gravitational pull of a blackhole did increase and then decrease, wouldn't it allow some light to occasionally escape it's pull and appear to us to be some sort of intergalactic light house ?
Well, I'm not really suggesting that it drops to a low enough level to allow light to escape. Even a variance between 100 billion and 90 billion can create a one way transfer of energy.

8. Just a reminder that a black hole is just the remnants of a massive star thats gone supernova, then collapse in on itself. Is it really so mysterious?

9. I think i said this before, but if very massive objects orbit a black hole, its axis might wobble causing it to eat the surrounding matter faster than usual, but the net gravitational field would only get bigger in the direction of its center. But, maybe a stupid question, but how does the gravitational field exit the black hole if the escape velocity is more than C?

10. I do disbelive a black hole was to become unstable in some way. It should fit to it's galaxy.

11. Originally Posted by KALSTER
I think i said this before, but if very massive objects orbit a black hole, its axis might wobble causing it to eat the surrounding matter faster than usual, but the net gravitational field would only get bigger in the direction of its center. But, maybe a stupid question, but how does the gravitational field exit the black hole if the escape velocity is more than C?
Quite simply: Gravity is a distortion of space-time, light trying to escape would be bent by the mass of the blackhole greater than its velocity can overcome.

12. Originally Posted by Kalster
I think i said this before, but if very massive objects orbit a black hole, its axis might wobble causing it to eat the surrounding matter faster than usual, but the net gravitational field would only get bigger in the direction of its center. But, maybe a stupid question, but how does the gravitational field exit the black hole if the escape velocity is more than C?
I wonder if the fact that a lot of the matter is continually hitting the light speed limit as it gets accelerated around might actually cause what I think you're suggesting.

Usually the center of mass is fixed in smaller bodies like Earth, but then Earth's gravity isn't strong enough to accelerate things close to C.

If one part of the mass cannot be accelerated further, but the rest can be accelerated further, it's at least possible to imagine the center of gravity moving around from time to time.

If the actual center of gravity moves, that would affect objects in orbit around it by pulling or slackening its pull on them slightly as it moves closer or further away from them.

13. Originally Posted by kojax
Originally Posted by Kalster
I think i said this before, but if very massive objects orbit a black hole, its axis might wobble causing it to eat the surrounding matter faster than usual, but the net gravitational field would only get bigger in the direction of its center. But, maybe a stupid question, but how does the gravitational field exit the black hole if the escape velocity is more than C?
I wonder if the fact that a lot of the matter is continually hitting the light speed limit as it gets accelerated around might actually cause what I think you're suggesting.

Usually the center of mass is fixed in smaller bodies like Earth, but then Earth's gravity isn't strong enough to accelerate things close to C.

If one part of the mass cannot be accelerated further, but the rest can be accelerated further, it's at least possible to imagine the center of gravity moving around from time to time.

If the actual center of gravity moves, that would affect objects in orbit around it by pulling or slackening its pull on them slightly as it moves closer or further away from them.
There was an other thought I had. Was gravity of a black hole same as earths gravitation? Caused
by the same effect? Or, do we just observe a same attraction of masses?

14. how big would a neutron star have to be for the escape velocity to exceed C? someone said that a star goes supernova and then collapses to form a black hole (singularity) if big enough, but is that the only way? lets say for example a neutron star gains enough mass to have an event horizon bigger than the radius. if something then crashes in to it at great speed what would happen if the body of the stellar object got broken up by the impact? would the black hole be destroyed? i'm actualy wondering about another mechanism for them to form that would not require a singularity and so there need not be any distinction between the gravitational fileds of black hole vs normal bodies like earth

15. Originally Posted by KALSTER
how big would a neutron star have to be for the escape velocity to exceed C? someone said that a star goes supernova and then collapses to form a black hole (singularity) if big enough, but is that the only way? lets say for example a neutron star gains enough mass to have an event horizon bigger than the radius. if something then crashes in to it at great speed what would happen if the body of the stellar object got broken up by the impact? would the black hole be destroyed? i'm actualy wondering about another mechanism for them to form that would not require a singularity and so there need not be any distinction between the gravitational fileds of black hole vs normal bodies like earth
What mechanism are you thinking about?

16. I wonder if the fact that a lot of the matter is continually hitting the light speed limit as it gets accelerated around
Nope, none of that matter comes close (95% or more of c) because when a body with a mass at rest >0 is accelerated to c than his mass reaches infinity and so a SuperBlack Hole would be created and this really would mean the end as the universe as we know it. But then again, the energy needed to accelerate something except Photons to c also reaches infinity.

lets say for example a neutron star gains enough mass to have an event horizon bigger than the radius
You have something mixed up there. The event horizon is a function of the mass of the BH and not something that can be put in relation to the physical dimensions of e.g. a neutron star. Space time fabric in a BH is bent is such a way that nothing escapes (and that concept was actually first though of in the 18th century). It does not make sense to put diameter of event horizon = diameter of black hole

But the mechanism of a neutron star aquiring enough mass from another nearby star bekomming a black hole actually really happens, but the energy that' generated during this process does not get transferred to the black hole. Most of it is converted to gamma- x- and UV-rays in this process and so is lost into the surrounding space. And if something big enough collides with a BH at relativistiv speeds does not mean a head-on collision. Both objects will rotated around each other until they finally merge and that's all that happens. This and a lot of gravity waves will be generated, thats why astronomers are actually looking for events like this to be able to prove the existence of gravity waves with LIGO

17. i always thought of the event horizon as the border between escapevelocity > C and escape veloticy < C. the closer to the mass the higher escape velocity and the farther, the lower. so is it not possible then for something to have enough mass for the escape velocity to be >= C on its surface or close to it without it collapsing into a singularity?

18. I think yes. If the escape velocity was > c light could escape (let us assume light was faster than itself in this case ).

19. well if it is indeed possible, then how could one tell the difference between a black hole with a singularity at it's centre and a body with enough mass for an event horizon to form?

20. Was the body with the event horizon to form the singularity in the black holes center? If not,
it's no possible at all.

21. Originally Posted by Twaaannnggg
I wonder if the fact that a lot of the matter is continually hitting the light speed limit as it gets accelerated around
Nope, none of that matter comes close (95% or more of c) because when a body with a mass at rest >0 is accelerated to c than his mass reaches infinity and so a SuperBlack Hole would be created and this really would mean the end as the universe as we know it. But then again, the energy needed to accelerate something except Photons to c also reaches infinity.
Yes, but that is more or less the same thing. Coming close to C is just an imperfect version of the same effect.

The amount of force per gram needed to accelerate one part of the mass further is greater than the amount of force per gram needed to accelerate the other further.

You're right though, that this has to be taken into account. It never becomes infinity hard to accelerate one side further. You just get ever diminishing returns on the force you apply to it until the returns begin to get very close to zero.

lets say for example a neutron star gains enough mass to have an event horizon bigger than the radius
You have something mixed up there. The event horizon is a function of the mass of the BH and not something that can be put in relation to the physical dimensions of e.g. a neutron star. Space time fabric in a BH is bent is such a way that nothing escapes (and that concept was actually first though of in the 18th century). It does not make sense to put diameter of event horizon = diameter of black hole

But the mechanism of a neutron star aquiring enough mass from another nearby star bekomming a black hole actually really happens, but the energy that' generated during this process does not get transferred to the black hole. Most of it is converted to gamma- x- and UV-rays in this process and so is lost into the surrounding space. And if something big enough collides with a BH at relativistiv speeds does not mean a head-on collision. Both objects will rotated around each other until they finally merge and that's all that happens. This and a lot of gravity waves will be generated, thats why astronomers are actually looking for events like this to be able to prove the existence of gravity waves with LIGO
It's all driven by density. Usually an object dense enough to have an even horizon begins crushing in on its own self and increasing its own density. It seems that nobody even knows if there's a limit on how dense it gets.

22. It's all driven by density. Usually an object dense enough to have an even horizon begins crushing in on its own self and increasing its own density. It seems that nobody even knows if there's a limit on how dense it gets.
that's what i was getting at. if nothing denser than a neutron star can exit, would it be able to have enough mass for an event horizon above its surface before it collapses into a singularity? i have read about people speculating about quark stars, and i've been wondering if singularities need to exist at all? is there nothing that can counterbalance the effects of gravity to prevent a singularity?

23. Well, I guess it's not just density. It's a combination of density and total mass. It's a question of whether a beam of light can reach the event horizon before it gets slowed all the way down to zero and pulled back in.

That makes it a combination of how much force is pulling on it, and how far it has to go to reach that event horizon. That second part depends more on the total mass.

24. kojax,

KALSTER meant if there wasn't something that would prevent a star from becoming a singularity, I think.

25. yes, thanks steve

26. What I think an other good question was, what criteria let a dying star become a singularity? Not each one will become one, right? Any thought's
anyone? (But, therefore there was a balance yet. Sorry, if this was your initial question/thought. )

27. yes, it is supposed to have more than a certain amount of mass to become a black hole. if not it would become a white dwarf. some stars become red giants, other go supernova. i'm not sure if a star would have enough mass left over to become a black hole after having gone supernova, but maybe someone knows.

28. Im pretty sure a star has to go supernova before it becomes a black hole (I could reference it but cant be bothered). I believe the energy from secondary nuclear interaction becomes too little to resist gravity. Hence you get a black hole or neutron star.

29. If the star is able to throw enough mass out into space during its supernova stages, then it won't have enough left to become a black hole.

I think the real question is, how does matter behave when you super, super, super compact it. We know what happens when you fuse atoms together, but we don't seem to know what would happen if you squished them so tight that even fusing wouldn't make more room.

30. Its only able to throw out certain elements. I believe most(if not all) of the transitioned hydrogen.helium nuclei remains to be condensed down. A star meeting the threshold size to become a black hole will always become one. The death of a star is very deterministic, thats why type II supernovae make good standard candles.

31. http://en.wikipedia.org/wiki/Degener...ark_degeneracy

here are the answers, or lack of answers. most phycisists believe that past neutron degenerate pressure, nothing would stop the collapse to a black hole. but they don't really know, since it is very diificult to do the equations of state for the degenerate matter. so a neutron star might collapse to a quark star and then further to a preon star and etc etc. so maybe ultimately infinite pressure is needed for something to have infinite density. as far as we are concerned, a black hole would behave the same whether it has a singularity at it's core or degenerate matter of some sort.

32. So then, do stars have a minimum amount of mass even left to become a black hole? I think all the statements that were made
need to consider several black wholes defining several galaxies in several shapes.

An other thought. Galaxies might be of the same shape, but of other stages, and do black holes changes as they, and their
galaxies, become older? Still an other idea, do they have, as they might have had a minimum amount of a stars mass, at the
end, however, a minimum of time to grow or can they also be shorta living singularity?

33. i think only super massive black holes in galactic centres are directly linked to the age of the galaxy. these black holes would have the best chance of having a singularity at its centre. as far as evolution of a black hole goes, that would happen if the black hole's core changed from, say, a quark star to a preon star

34. So the idea of ever being same to some extend and repeating observed being in several stages was wrong? Generally to expel?

35. So the idea of ever being same to some extend and repeating observed being in several stages was wrong? Generally to expel?
not sure what you mean. observable differences might be the amount of matter around the black hole changing or suddenly disappearing or something happening to it. i don't think, if the different cores theory is true, that we would be able to tell the difference. tha matter would still be swallowed the same way i think

36. but just to be sure, i don't have any qualifications so all this might be worthless horse semen

37. Originally Posted by KALSTER
So the idea of ever being same to some extend and repeating observed being in several stages was wrong? Generally to expel?
not sure what you mean. observable differences might be the amount of matter around the black hole changing or suddenly disappearing or something happening to it. i don't think, if the different cores theory is true, that we would be able to tell the difference. tha matter would still be swallowed the same way i think
What should the singularities being good for? There should be a 'cause' for them being as
well as an effect they should have.

38. the cause is what most astrophysicists believe, that beyond neutron degenerate force, it would continue to collapse into a singularity. quark stars and peon stars are just possible alternatives.

39. I think i know now what you meant. Took me a while you know. I think it's unusual and no recorded data shows such a singularity as for my knowledge. What came up to my mind first, how could such a singularity survive the birth of the black hole and further live of it (let's name it that way for the moment). It couldn't get there afterwards I guess.

40. No! dont quote wiki! learn what you are talking about!

41. i am trying to do that here. anything to ad ghost?

42. quack

43. :?

44. Well, you left me speechless. Sort of. I thought you guys are serious.

45. Well, you left me speechless. Sort of. I thought you guys are serious.
i am. i was trying to figure out what happens when a star collapses. seems according to GhostofMaxwell, we can only talk about this if we studied it? and what is wrong with quoting wiki, since it is there that i had just "learned" the answers that i was looking for?

46. I dont consider wiki reliable, NASA may be a better source.

47.

48. Originally Posted by KALSTER
Well, you left me speechless. Sort of. I thought you guys are serious.
i am. i was trying to figure out what happens when a star collapses. seems according to GhostofMaxwell, we can only talk about this if we studied it? and what is wrong with quoting wiki, since it is there that i had just "learned" the answers that i was looking for?
A dying star will not be of much magic. It's, more or less, like an oven or fire that was not being
fed no longer. All resources are burned and the fire goes off. That are my thoughts about a dying
star.

Not much miraculous going on there I think.

49. Originally Posted by GhostofMaxwell
I dont consider wiki reliable, NASA may be a better source.
If you're after reliable information....... maybe astronomy isn't the best topic for discussion. Even the most reliable sources have to make a lot of guesses. The better half of everything we think we know is speculation, or at least a quarter of it. (I'd have to speculate as to how much of it, exactly, is observation and how much is speculative)

One consequence of an oscillating gravitational field might be that stars orbiting it would orbit at different than expected speeds. Nearer stars might vary by a different amount than stars orbiting further out.

50. Originally Posted by kojax
Originally Posted by GhostofMaxwell
I dont consider wiki reliable, NASA may be a better source.
If you're after reliable information....... maybe astronomy isn't the best topic for discussion. Even the most reliable sources have to make a lot of guesses. The better half of everything we think we know is speculation, or at least a quarter of it. (I'd have to speculate as to how much of it, exactly, is observation and how much is speculative)

One consequence of an oscillating gravitational field might be that stars orbiting it would orbit at different than expected speeds. Nearer stars might vary by a different amount than stars orbiting further out.
What ever!

For the people who are willing to learn rather than fantasize they are the next Steven Hawkin, though......NASA is thought reliable by education establishments, while wiki is thought to be a jolly jaunt on the information super highway, rather than a reliable science source.

51. Originally Posted by Steve Miller
A dying star will not be of much magic. It's, more or less, like an oven or fire that was not being
fed no longer. All resources are burned and the fire goes off. That are my thoughts about a dying
star.

Not much miraculous going on there I think.
I wouldn't call that boring............. Depending on the size of the star the cycles he's going through are quite interesting. For example, after H-H or He-He fusion what comes next? C-C or O-O fusion is (at least in my eyes) tremendously interesting. How does it work in the first place (we just have sufficient models for H-H and He-He fusion but not for al the other steps further down the road). I mean, the heavier elements are created in a Nova/Supernova and we all depend on that (carbon based life forms that is)
And what about the seismic processes hapening in/on/aroud a star during it collapses? Or how the heck does matter get so compressed to form exotic matter like Neutronstar/Quark Star matter? Or what happens to a massive object like a Neutron Star revolving at several thousand Htz? Are there planets around Neutron Stars etc.

52. Very true!

53. Originally Posted by GhostofMaxwell
Originally Posted by kojax
Originally Posted by GhostofMaxwell
I dont consider wiki reliable, NASA may be a better source.
If you're after reliable information....... maybe astronomy isn't the best topic for discussion. Even the most reliable sources have to make a lot of guesses. The better half of everything we think we know is speculation, or at least a quarter of it. (I'd have to speculate as to how much of it, exactly, is observation and how much is speculative)

One consequence of an oscillating gravitational field might be that stars orbiting it would orbit at different than expected speeds. Nearer stars might vary by a different amount than stars orbiting further out.
What ever!

For the people who are willing to learn rather than fantasize they are the next Steven Hawkin, though......NASA is thought reliable by education establishments, while wiki is thought to be a jolly jaunt on the information super highway, rather than a reliable science source.
Nasa is probably as reliable as it gets. It just worries me to hear people talk about reliability in a field that is largely speculative. The myth of reliable information has always been a stumbling block to scientific progress.

Galileo dared to say that even one Catholic held belief was incorrect and they threatened to burn him at the stake. They preferred to believe that their speculations were facts, and not to be questioned, when in fact the people of the time had no reliable way to conclude anything with certainty.

That's the problem. Until you have a way to know things for sure, you have to keep aware of your margins of error.

As far as astronomy is concerned, we don't have the technological means to know a lot of things for sure. There are some things we can be sure of, and others we have to just be content to speculate about.

54. But then how exactly do gravitational pulsars work? Aren't those "oscillations" in the gravity?

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