Confusing Scientific Thought experiment of mine?
| black hole actually has so much rest mass that when objects are sucked into it, they are actually destroyed by the immense gravitational fields, |
Well of course objects are not destroyed, they just join the black holes mass and then are eventually re-emitted by the black hole.
| where as for the one that only appears like a black hole this will not be the case. |
I thought about this and it cannot look like a black hole. Let's say I'm standing in front of an Earth going at 0.9999999999999999999c and before it reaches me, I fire a laser at it. Some of the photons are going to reflect back to my detector. If you
Edit: It's clear where.
Last edited on
Well you would have the effect of time dilation which would slow down the process of absorption and emission such that light would take a very long time to reflect, and it would be red shifted so much you may not be able to detect it, similar to a black hole. If you were actually going the speed of light, then light would not reflect back at all because the process would be frozen in time.
| and it would be red shifted so much you may not be able to detect it, similar to a black hole |
But if your detector was sensitive enough... What I mean is, you can only mistake it for a black hole because of your own lack of ability rather than the physics of a near-c moving Earth and black hole being indistinguishable. Edit: A black hole doesn't red-shift the light, it just absorbs it.
| If you were actually going the speed of light, then light would not reflect back at all because the process would be frozen in time. |
You can't really say what would happen "if you were going at the speed of light." I mean to reach such a speed, you would have infinite mass-energy and infinite momentum. In fact, you would be infinitely larger (in mass) than the entire universe while having an infinitely small area. None of this makes any sense because it breaks many laws of physics.
Last edited on
closed account (13bSLyTq)
According to the article presented above it says that a truly fast enough object can become a Black-Hole due to relativistic compression, that being said it would become a black hole at some point or another. But will the other frame (of people on earth) become a black hole or be sucked into a blackhole by other object.
That being in mind, what would happen once we decelerate\stop will the object be turning back into original object or will it be lost forever.
Next, my question does not break any laws of physics as far as I know, as I'm not breaking any GR rules.
That being in mind, what would happen once we decelerate\stop will the object be turning back into original object or will it be lost forever.
Next, my question does not break any laws of physics as far as I know, as I'm not breaking any GR rules.
| According to the article presented above it says that a truly fast enough object can become a Black-Hole due to relativistic compression |
The article Cody posted? Because that did not...
| that being said it would become a black hole at some point or another. |
Why? You can always fire a photon and this object and get a signal back. There is no horizon.
| Next, my question does not break any laws of physics as far as I know, as I'm not breaking any GR rules. |
General relativity is an incomplete theory of gravity. There are many other laws of physics that must be obeyed, such as quantum mechanics.
Last edited on
closed account (13bSLyTq)
Well your right, but it says:
If it is behaves exactly to a that of an black hole but its not but as it acts like a blackhole its gravity would increase to the observer but NOT to the people on earth then does this mean that Gravity is relative to observer.
Next, if it does become a black-hole or at least mimic it then surely where does matter go\lead then if it fall into it.
very fast spacecraft can appear to be almost indistinguishable from a black hole – from a particular frame (or frames) of reference. |
If it is behaves exactly to a that of an black hole but its not but as it acts like a blackhole its gravity would increase to the observer but NOT to the people on earth then does this mean that Gravity is relative to observer.
Next, if it does become a black-hole or at least mimic it then surely where does matter go\lead then if it fall into it.
| very fast spacecraft can appear to be almost indistinguishable from a black hole – from a particular frame (or frames) of reference. |
This basically means if you lack the appropriate tools to make a proper judgement...
If it is behaves exactly to a that of an black hole but its not but as it acts like a black hole its gravity would increase to the observer but NOT to the people on earth then does this mean that Gravity is relative to observer. |
Firstly, it is not behaving like a black hole, because it is not a black hole. An observer in another frame of reference would not feel any more gravity from the rapidly moving (but same mass) Earth than from a stationary one. So no, gravity is not relative in the sense you mean (it is relative to distance away from the gravitational source).
| Nwhere does matter go\lead then if it fall into it |
If we extend this question to say "what happens when matter enters an actual black hole" it seems the answer is very little. If you were falling into a black hole and of a sufficiently small size (so as to avoid being torn apart by tidal forces before reaching the horizon), nothing special would happen as you crossed the horizon. Once in the black hole, it's a matter of conjecture about exactly what happens, but it seems you won't be seeing any of it anyway, since all paths for light will lead into the singularity anyway. You just get to wait in there for (probably) a very long time until you are re-emitted as Hawking radiation.
Last edited on
closed account (13bSLyTq)
Okay, then as you speed up to a high enough velocity would Lorentz–FitzGerald contraction come into play and we should in theory get denser and denser until we do become a black hole while remaining at the same rest mass but we simply get denser and denser until we actually become an blackhole.
So that being said should it not apply to this thought experiment?
As
in theory it should apply to other objects like Earth in our case and due to this taken to extreme we should in theory become an blackhole.
So that being said should it not apply to this thought experiment?
As
| Heavy ions that are spherical when at rest should assume the form of "pancakes" or flat disks when traveling nearly at the speed of light. And in fact, the results obtained from particle collisions can only be explained, when the increased nucleon density due to length contraction is considered |
Last edited on
Yes gravity essentially is relative because it is a property of space-time and both space and time are relative. And energy is relative as well. For instance according to the outside observer you may have an enormous amount of momentum and energy, but to another you may have only rest mass and no kinetic-energy.
What is undisputed is that the object that "becomes black hole like from the perspective of some other frame of reference due to extreme relative velocity", is no different in it's own frame. i.e. no effects would be noticed at all in anyone's own frame.
The thing is we know very little about black holes.
I don't think this is true. You would feel the gravity from the relativistic mass that the other observer has when viewed from your frame, and the same thing the other way around.
What is undisputed is that the object that "becomes black hole like from the perspective of some other frame of reference due to extreme relative velocity", is no different in it's own frame. i.e. no effects would be noticed at all in anyone's own frame.
The thing is we know very little about black holes.
An observer in another frame of reference would not feel any more gravity from the rapidly moving (but same mass) Earth than from a stationary one. |
I don't think this is true. You would feel the gravity from the relativistic mass that the other observer has when viewed from your frame, and the same thing the other way around.
Last edited on
| I don't think this is true. You would feel the gravity from the relativistic mass that the other observer has when viewed from your frame, and the same thing the other way around. |
Yes you feel the gravity, but since the mass is radiating away mass at the same rate as the mass increase due to acceleration in this experiment, gravity remains unchanged. Otherwise, you are getting extra gravitational field strength from literally nowhere.
closed account (13bSLyTq)
But you would get gravity from the Lorentz-Fitzgerald contraction due to increase in density of the object.
| But you would get gravity from the Lorentz-Fitzgerald contraction due to increase in density of the object. |
You do not get an extra gravity. The only way to increase the gravitational field strength of an object is to increase its mass. Since your own experimental conditions keep overall mass constant, the gravity produced by the system will also be constant. For an observer outside of the reference frame of the fast moving Earth, no change in the gravitational field will be made.
closed account (13bSLyTq)
Are you sure, even you can become an blackhole. Look here: http://www.universetoday.com/33454/how-do-black-holes-form/
its ays:
or Wikipedia says:
That being said, due to Lorentz-Fitzgerald contraction the object (earth) will get sufficiently compact at some point in the frame of reference thus increasing in gravity and finally becoming an black hole.
its ays:
| Take the mass of an entire star. Compress it down into an object so compact that the force of gravity defies comprehension. |
or Wikipedia says:
| general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. |
That being said, due to Lorentz-Fitzgerald contraction the object (earth) will get sufficiently compact at some point in the frame of reference thus increasing in gravity and finally becoming an black hole.
| That being said, due to Lorentz-Fitzgerald contraction the object (earth) will get sufficiently compact at some point in the frame of reference thus increasing in gravity and finally becoming an black hole. |
How would you accelerate an object to such a speed without using a black hole to accelerate it (where I suspect the velocity required to reach black hole status lies within the horizon anyway)?
Edit:
| For an observer outside of the reference frame of the fast moving Earth, no change in the gravitational field will be made. |
100% sure of this. You can't increase gravitational field strength without adding mass. This violates the law that energy cannot be created or destroyed (you would be making more gravitational energy from nothing).
Last edited on
closed account (13bSLyTq)
You don't need that to accelerate using a blackhole for this to happen look, look at Lorentz-Fitzgerald contraction, if you accelerate to a extremely fast velocities (near Light Speed, in fact at speeds of 10x of Gamma Ray burst particle speeds) you will reduce in size and compress it down to amazingly small percentage like 0.000000000000000000009% to its original length therefore you make it a super-dense object and finally a black hole.
As for your edit:
Due to energy being inputted into the initial body in our case (Earth) the speed would increase in form of Kinetic Energy therefore Lorentz-Fitzgerald contraction takes place and essentially we are squashing it rather than adding mass and creating gravity.
As for your edit:
Due to energy being inputted into the initial body in our case (Earth) the speed would increase in form of Kinetic Energy therefore Lorentz-Fitzgerald contraction takes place and essentially we are squashing it rather than adding mass and creating gravity.
| in fact at speeds of 10x of Gamma Ray burst particle speeds |
Okay and how you gonna do that? I mean, without using a black hole...
| we are squashing it rather than adding mass and creating gravity. |
Are we now at least in agreement on this point (that gravitational measurements outside of Earth's reference frame remain the same)?
| 100% sure of this. You can't increase gravitational field strength without adding mass. This violates the law that energy cannot be created or destroyed (you would be making more gravitational energy from nothing). |
How much energy and mass something has depends on where you look at it from.
Last edited on
Here is a paper which discusses the issue.
http://arxiv.org/PS_cache/gr-qc/pdf/9909/9909014v1.pdf
| According to the general theory of relativity, kinetic energy contributes to gravitational mass. Surprisingly, the observational evidence for this prediction does not seem to be discussed in the literature. I reanalyze existing experimental data to test the equivalence principle for the kinetic energy of atomic electrons, and show that fairly strong limits on possible violations can be obtained. I discuss the relation ship of this result to the occasional claim that “light falls with twice the acceleration of ordinary matter.” |
http://arxiv.org/PS_cache/gr-qc/pdf/9909/9909014v1.pdf
Last edited on
| Are we now at least in agreement on this point (that gravitational measurements outside of Earth's reference frame remain the same)? |
I still think this is incorrect. Well maybe it's possible it's correct, but it is in opposition to the Theory of General Relativity.
| we are squashing it rather than adding mass and creating gravity. |
At relativistic velocity you get all of the effects that come with it, including added mass, length contraction and time dilation.
Last edited on
| if you accelerate to a extremely fast velocities (near Light Speed, in fact at speeds of 10x of Gamma Ray burst particle speeds |
Why not just make it easy. Pick a neutron star that is already at the exact threshold of becoming a black hole, its velocity relative to you 0. Now start moving.
But just because it is more massive and dense when viewed from your frame doesn't mean it is more massive and dense in it's own reference frame.
Last edited on