|
|
|
|
|
| Rate of Acceleration & Relativity ala Black Hole
Posted: 8/18/2009 9:28:53 AM | The rod thing doesn't work. A disturbance in the rod can't move faster than the speed of sound in the rod, which cannot be faster than the speed of light, even if for no other reason than that the disturbance propagates by electromagnetic interactions that are mediated by photons, which go at the speed of light. Nice try, though.
Also, you can't have a rod of some magic substance that doesn't have this property. That's excluded by QM. This is one of the nice ways in which relativity and QM seem to complement each other. The more weird things are discovered, the more it looks like the weirdnesses have to be there. For example, in a completely classical universe with purely Newtonian gravity and unlimited speed, it would be theoretically possible to arrange some masses in a gravitational system such that one of them can go to infinity in a finite time. Assuming that is absurd, we can show using just mathematics that the assumptions are wrong.
By the "surface," maybe the OP means the event horizon. The area of that is a measure of the entropy of the black hole and inversely related to the temperature. (I'm not going to say "propotional" because people put logs and stuff in measures of entropies depending on how they want them to work.) | |
|
| Rate of Acceleration & Relativity ala Black Hole
Posted: 8/18/2009 10:33:19 AM |
The rod thing doesn't work. A disturbance in the rod can't move faster than the speed of sound in the rod, which cannot be faster than the speed of light, even if for no other reason than that the disturbance propagates by electromagnetic interactions that are mediated by photons, which go at the speed of light. Nice try, though.
Thanks for that, I knew a 300,000km rod was a bit farfetched, but it just seems an intuitive thing. Like, if one pushes on one side of a solid object then the side furthest away starts moving at the same time.
As in, if one were to give the toaster on the bench a bit of a nudge, there's no observable delay before the other side of it starts moving. I guess it would be clearer though if it was a million slice toaster, and the kitchen bench was really long... | |
|
| Rate of Acceleration & Relativity ala Black Hole
Posted: 11/6/2009 5:00:13 AM | Abelian my mathmatics is not up to the level you use.
Can I ask this question.
Assuming a non spinning black hole exists.
Its "gravity" attracts mass from the surrounding sphere of influence.
The mass continuously accelerates towards the black hole to collosal velocities.
Is it possible the mass approaches the velocity of light ?
I have read that photons can not return from the black hole or a sphere surrounding it.
Photons are Electro magnetic energy so presumably alll EME would be similarly influenced.
If EMG also applies to Gravity then how can it influence the mass outside the sphere surrounding the blackhole.
Would this not suggest that gravity is not a wave? | |
|
| Rate of Acceleration & Relativity ala Black Hole
Posted: 11/6/2009 7:13:43 AM | There are lots of questions I have about black holes as my knowledge is very limited.
Can anyone explain to me in fairly simple language why it is that quantum physics and the theory of relativity, apparently do not equate when it comes to black holes and that strange event called singularity?.....which I still do not understand.
The other question I have is what the hell is quantum gravity? | |
|
| Rate of Acceleration & Relativity ala Black Hole
Posted: 11/6/2009 8:12:32 AM |
There are lots of questions I have about black holes as my knowledge is very limited. That's understandable. A lot of top physicists who devoted themselves to black holes say that they don't understand black holes either.
Can anyone explain to me in fairly simple language why it is that quantum physics and the theory of relativity, apparently do not equate when it comes to black holes and that strange event called singularity?.....which I still do not understand. Black holes appear to have such a strong force of gravity, that each black hold pulls its mass into an infinitesimally small point, called a singularity. However, the theory of relativity concludes that the force of gravity of a singularity will be infinite. Such an infinite force would pull the entire universe into it, in a single moment. That clearly doesn't happen.
I'm not an expert, but that's basically what some top black hole physicists said in interviews shown on Tuesday.
The other question I have is what the hell is quantum gravity? It's a theory which tries to unify quantum mechanics with relativity, by attempting to describe how gravity would work on the quantum level. | |
|
| |
| Rate of Acceleration & Relativity ala Black Hole
Posted: 11/8/2009 6:29:24 AM |
Can anyone explain to me in fairly simple language why it is that quantum physics and the theory of relativity, apparently do not equate when it comes to black holes and that strange event called singularity?.....which I still do not understand.
Actually, it's a question of scale.
Relativity occurs at the macro scale...things like stars, planets and people. However, QT applies to the sub-atomic and below. Now gravity has its greatest influence at the macro scale. The more mass a body has, the greater its gravity. However, at the subatomic scale, forces like the strong and weak nuclear forces, as well as electromagnetism are orders of magnitude stronger than gravity.
The problem is the singularity. It has the mass of a star, but is condensed into an infinitely small point. Gravity becomes the dominant force, approaching infinity. And, according to theorists, infinities are a problem in the mathematics because it doesn't really answer any questions, amongst others.
Enrique mentioned gravity waves. Yes, gravity waves are a prediction of Relativity and result from mass moving through the spacetime continuum. Indeed, gravity waves are basically "information" about the mass that existed. Since nothing can travel faster than the speed of light in Relativistic space, then any information about something like a star would be limited to that speed.
If the sun were to suddenly disappear, for instance, Earth would continue in its orbital path for an additional 8 minutes (the Sun - Earth light travel time) before it would go careening off into space. | |
|
|
|
Home
login 
