Quantum Gravity & Black Holes

IIRichard · 26th April 2006, 01:01 PM

Theory: Nothing can escape from a black hole 'cause the gravity is so strong the escape velocity is higher than the speed of light. Not even massless particles like photons can escape. And I'm ignoring zero point vacuum energy particle pairs at the event horizon.

So, IF gravity is mediated/carried by/caused by some sort of particle, how does it get out of a black hole?

IIRichard

Yllanes · 26th April 2006, 01:55 PM

A good question. Check the Usenet Physics FAQ (short and to the point). I can elaborate if you still have doubts.

IIRichard · 26th April 2006, 02:02 PM

Thank you. That was it. And also thanks for pointing out the physics FAQ, which I have bookmarked.

Yllanes · 26th April 2006, 02:54 PM

Originally Posted by IIRichard

Thank you. That was it. And also thanks for pointing out the physics FAQ, which I have bookmarked.

You are welcome. The FAQ is a very good resource and usually one of the first steps if you have a doubt and want to research it a bit.

Art Vandelay · 28th April 2006, 02:52 PM

So I guess the answer is because from the view outside the black hole, the black hole never actually forms (it takes an infinite amount of time for the star to collapse into a black hole)? I take issue with that FAQ, though. Its statement that energy must be quantized is rather misleading. Given a particular frequency of light, energy is quantized. But a photon can have any amount of energy.

IIRichard · 29th April 2006, 04:14 PM

Another question. If virtual particles (theoreticaly) can escape a black hole, then, according to theory, information can escape the Hole. Yes/No?

JohnF_73 · 29th April 2006, 07:10 PM

Well, kind of... one way to look at it is that a virtual particle pair (an anti particle and a particle) form near the event horizon and the anti particle gets caught but the particle does not.

The anti particle goes into the black hole, and reacts to reduce the black holes mass. The particle from the virtual pair no longer has an anti particle with which to cancel. The net effect is that it looks as though a particle appears to be moving away from the black hole, and the BH's mass reduces by the amount in the particle.

That's one way a particle can appear to escape from a black hole, without violating the gravitational constraints.

26th April 2006, 01:01 PM	#1
IIRichard Critical Thinker Join Date: Feb 2005 Location: CT/NJ Posts: 290	Quantum Gravity & Black Holes Theory: Nothing can escape from a black hole 'cause the gravity is so strong the escape velocity is higher than the speed of light. Not even massless particles like photons can escape. And I'm ignoring zero point vacuum energy particle pairs at the event horizon. So, IF gravity is mediated/carried by/caused by some sort of particle, how does it get out of a black hole? IIRichard
	__________________ People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." - George Orwell

26th April 2006, 02:02 PM	#3
IIRichard Critical Thinker Join Date: Feb 2005 Location: CT/NJ Posts: 290	Thank you. That was it. And also thanks for pointing out the physics FAQ, which I have bookmarked.
	__________________ People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." - George Orwell

29th April 2006, 04:14 PM	#6
IIRichard Critical Thinker Join Date: Feb 2005 Location: CT/NJ Posts: 290	Another question. If virtual particles (theoreticaly) can escape a black hole, then, according to theory, information can escape the Hole. Yes/No?
	__________________ People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." - George Orwell

29th April 2006, 07:10 PM	#7
JohnF_73 Thinker Join Date: Sep 2004 Posts: 151	Well, kind of... one way to look at it is that a virtual particle pair (an anti particle and a particle) form near the event horizon and the anti particle gets caught but the particle does not. The anti particle goes into the black hole, and reacts to reduce the black holes mass. The particle from the virtual pair no longer has an anti particle with which to cancel. The net effect is that it looks as though a particle appears to be moving away from the black hole, and the BH's mass reduces by the amount in the particle. That's one way a particle can appear to escape from a black hole, without violating the gravitational constraints.
JohnF_73 Thinker Join Date: Sep 2004 Posts: 151

26th April 2006, 01:55 PM	#2
Yllanes Muse Join Date: Sep 2005 Location: Madrid Posts: 826	A good question. Check the Usenet Physics FAQ (short and to the point). I can elaborate if you still have doubts.

26th April 2006, 02:54 PM	#4
Yllanes Muse Join Date: Sep 2005 Location: Madrid Posts: 826	Originally Posted by IIRichard Thank you. That was it. And also thanks for pointing out the physics FAQ, which I have bookmarked. You are welcome. The FAQ is a very good resource and usually one of the first steps if you have a doubt and want to research it a bit.

28th April 2006, 02:52 PM	#5
Art Vandelay Illuminator Join Date: May 2004 Posts: 4,790	So I guess the answer is because from the view outside the black hole, the black hole never actually forms (it takes an infinite amount of time for the star to collapse into a black hole)? I take issue with that FAQ, though. Its statement that energy must be quantized is rather misleading. Given a particular frequency of light, energy is quantized. But a photon can have any amount of energy.