Topic: Van Den Broek's alcubierre metric variant warp space configuration

[Stormbringer]

No i referred to Einstein because it was said at the time only 6 people in the world could understand it; that it was to complex for all but the most hyper intelligent and hyper educated elite. Now it is quite common to run into someone who not only thinks they do but in fact actually do understand it. it's not that difficult.

Since relativity is so simple, then perhaps you can help me resolve this paradox?

When a massive object undergoes gravitational collapse and is crushed into a black hole, inside the Schwarzchild radius, nothing, not even particles with zero rest energy can escape...  This means that no quanta can escape the Schwarchild Radius, including gravitons, since space time within that distance from the singularity is curved right back inwards towards the singularity... 


Since Gravitons cannot escape, why does the black hole behave as a massive object with a powerful gravity field?

Two reasons: firstly gravity can be modelled as curvature of space rather than gravitons. gravitons have not been observed. if they exist they have to have a nature related to that curve of space the very "fabric" they are made of is different than photons themselves a massless hadron exchange particle which isn't slowed so much as redirected. however the LIGO and other experiments have not verified that gravity waves and therefore gravitons even travel following the same restrictions photons do. Finally black holes can release particles via tunneling the so called Hawking radiation. they evaporate.

EDIT:  I did not resort to relativity for those explanations; sorry. i never have had to in this context. i can look it up if you want.

[E_Look]

Alternatively, gravitons could simply be viewed as just a quantization of gravitational force... rather, gravitationally related energy, much like a light wave can alternatively be viewed as a collection of photons.

And,

"modeling gravity as just the curvature of space" is just like saying there is a gravitational field in the region, and visualizing the region as rectilinear.

See, no one really understands fields, like magnetic, electric, or gravitational fields.  Einstein never liked "spooky action at a distance" explanations, and his stature no doubt colors the minds of many younger scientists coming after him, philosophically.  But something exists, be it a field, lines of force, gravitons, Maxwellian demons with nylon fishing lines yanking at things.  Because we don't have a real handle on these things, we posit differently dressed, but equivalent attempts at explanation for them.

[Stormbringer]

But while we can manipulate photons with fiber optic cables mirrors, polarized lenses shields and so forth we cannot say the same of gravitons.  we cannot count gravitons but we can count photons.

[Dracho]

Ah... gravity... now that's a heavy subject.

[Stormbringer]

*Groan*

[prometheus]

No i referred to Einstein because it was said at the time only 6 people in the world could understand it; that it was to complex for all but the most hyper intelligent and hyper educated elite. Now it is quite common to run into someone who not only thinks they do but in fact actually do understand it. it's not that difficult.

Since relativity is so simple, then perhaps you can help me resolve this paradox?

When a massive object undergoes gravitational collapse and is crushed into a black hole, inside the Schwarzchild radius, nothing, not even particles with zero rest energy can escape...  This means that no quanta can escape the Schwarchild Radius, including gravitons, since space time within that distance from the singularity is curved right back inwards towards the singularity... 


Since Gravitons cannot escape, why does the black hole behave as a massive object with a powerful gravity field?

Two reasons: firstly gravity can be modelled as curvature of space rather than gravitons. gravitons have not been observed. if they exist they have to have a nature related to that curve of space the very "fabric" they are made of is different than photons themselves a massless hadron exchange particle which isn't slowed so much as redirected. however the LIGO and other experiments have not verified that gravity waves and therefore gravitons even travel following the same restrictions photons do. Finally black holes can release particles via tunneling the so called Hawking radiation. they evaporate.

EDIT:  I did not resort to relativity for those explanations; sorry. i never have had to in this context. i can look it up if you want.

The effects of Hawking radiation are negligible, so let's forget about the second reason you've given here...

But you did resort to relativity....  Modeling gravity with Spacetime curvature is one of the prime maxims of relativity...  You can see my point I assume?  When you look at black holes thus, it becomes obvious why Quantum Theories of gravity break down with black holes...  To model gravity as space time curvature , one needs to resort to using the Thoery of Relativity.  In Quantum Thoery, with no particles escaping the black hole to create an interaction, there should be no gravity field around the black hole.  This is a schism that may never be resolved... 

[prometheus]

Alternatively, gravitons could simply be viewed as just a quantization of gravitational force... rather, gravitationally related energy, much like a light wave can alternatively be viewed as a collection of photons.

And,

"modeling gravity as just the curvature of space" is just like saying there is a gravitational field in the region, and visualizing the region as rectilinear.

See, no one really understands fields, like magnetic, electric, or gravitational fields.  Einstein never liked "spooky action at a distance" explanations, and his stature no doubt colors the minds of many younger scientists coming after him, philosophically.  But something exists, be it a field, lines of force, gravitons, Maxwellian demons with nylon fishing lines yanking at things.  Because we don't have a real handle on these things, we posit differently dressed, but equivalent attempts at explanation for them.

I concur... 

[E_Look]

But while we can manipulate photons with fiber optic cables mirrors, polarized lenses shields and so forth we cannot say the same of gravitons.  we cannot count gravitons but we can count photons.

Personally, I don't believe they (gravitons) exist; and even when on paper, it's...
                                                                                                                ... bad framing.

[prometheus]

But while we can manipulate photons with fiber optic cables mirrors, polarized lenses shields and so forth we cannot say the same of gravitons.  we cannot count gravitons but we can count photons.

Personally, I don't believe they (gravitons) exist; and even when on paper, it's...
                                                                                                                ... bad framing.

Out of curiosity E_Look, do you have any opinions on what gravity actually is if it is not a Quantum Interaction?

[E_Look]

First, that depends on what you mean by a "quantum interaction".  If you mean basic quantum mechanics, then I don't really see a connection except insofar as to use quantum mathematical techniques and physical principles to *DESCRIBE* (not explain) empirically how gravity behaves.  But I don't really see a quantization, or at least, I am not cognizant of, any quantization of energy due to gravitational interactions...

... now this won't apply to microscopic objects like atoms or subatomic particles, as any force or potential (well), as a gravity source, will cause quantization of energy levels.

So, my point is just that you might be able to call it a "quantum interaction" if there is observable quantization with respect to its energies, but this can exist really only for tiny particles, not huge things like planets, meteors, or even people or microbes.

That is, two subatomic particles, say, can approach each other and their native gravitational attractions, small as it might be as gravity's pull is based on amount of mass present, just might exhibit additional quantum effects due to yet another force acting upon them, even if from each other.

Now, if two asteroids or stars approach each other, I think the quantum effects will be lost in the wash way before people even realized these large objects might be on a collision course.

It really is a matter of scale!

But hey, Storm, don't stop, as I've said before.  Despite my sour countenance, there ARE a few GOOD ideas out there, and if nothing else, you're educating yourself (and me, too) like you might not believe!

[E_Look]

Ah!  I think I finally see what you mean!  Correct me if I'm wrong:

Yes, there will be quantum effects due to gravitational attraction, as any potential well can give rise to quantization effects on the microscopic level.  And, the summation of all those little quanta of energy DOES add up to the macroscopic (astronomical, too) gravitational effects we can more easily observe.

So, in that sense, yes, there can be the possiblility of quantum mechanical effects due to the gravitational attractions all mass has, no matter (sorry for the unintentional pun) what its size is.

Now, as to the very nature of that gravitational attraction, NO ONE but God knows... literally.

[Stormbringer]

Two types of time machine have been put forward recently both involved closed space like loops or varient space metrics. I've noticed a trend both methods ran into a similar limitation. both could allow time travel into the past *but only to the point in time where the machine was turned on.* all other methods  either shunted the traveller into an alternate timeline or to the end of the universe so they could not effect the past.

both of the two limited time travel methods are generally agreed by subject matter experts to be allowed by the known laws of physics.

Does this nexus of commonality between the two methods suggests a heretofore hidden principle of space-time?

The latest method is covered in this month's popular science magazine both on line and in the hard copy.

[prometheus]

First, that depends on what you mean by a "quantum interaction".  If you mean basic quantum mechanics, then I don't really see a connection except insofar as to use quantum mathematical techniques and physical principles to *DESCRIBE* (not explain) empirically how gravity behaves.  But I don't really see a quantization, or at least, I am not cognizant of, any quantization of energy due to gravitational interactions...

... now this won't apply to microscopic objects like atoms or subatomic particles, as any force or potential (well), as a gravity source, will cause quantization of energy levels.

So, my point is just that you might be able to call it a "quantum interaction" if there is observable quantization with respect to its energies, but this can exist really only for tiny particles, not huge things like planets, meteors, or even people or microbes.

That is, two subatomic particles, say, can approach each other and their native gravitational attractions, small as it might be as gravity's pull is based on amount of mass present, just might exhibit additional quantum effects due to yet another force acting upon them, even if from each other.

Now, if two asteroids or stars approach each other, I think the quantum effects will be lost in the wash way before people even realized these large objects might be on a collision course.

It really is a matter of scale!

But hey, Storm, don't stop, as I've said before.  Despite my sour countenance, there ARE a few GOOD ideas out there, and if nothing else, you're educating yourself (and me, too) like you might not believe!

I agree, but you must conceed that anyone who speaks of "gravitons" is postualting, whether they unserstand what they are saying or not, the existance of a quanta for gravitational interactions...

For myself, I have no opinion as yet whether gravity has a quanta or not, but with the evidence available at the moment, I would tend to be biased towards not....

[prometheus]

Two types of time machine have been put forward recently both involved closed space like loops or varient space metrics. I've noticed a trend both methods ran into a similar limitation. both could allow time travel into the past *but only to the point in time where the machine was turned on.* all other methods  either shunted the traveller into an alternate timeline or to the end of the universe so they could not effect the past.

both of the two limited time travel methods are generally agreed by subject matter experts to be allowed by the known laws of physics.

Does this nexus of commonality between the two methods suggests a heretofore hidden principle of space-time?

The latest method is covered in this month's popular science magazine both on line and in the hard copy.

It sounds more than a little far fetched to me...

[Stormbringer]

Now reading Scientific american's article; the illusion of gravity (holographic physics may explain nature's most elusive force.)

[Stormbringer]

Hmmmm. String based quantum gravity descriptions actually work in Anti-DE Sitter space metrics. [...still studying it]

[Stormbringer]

A quantum gravity theory in the interior of a anti-De-Sitter space time is compoletely equivelent to an ordinary quantum particle theory on the boudary of the ADS space. if this equivelence is true it means you can use quantum particle theory to define a quantum gravity theory. the beauty of this is that objects on the interior of an ADS experience gravity even though a distinct gravitational interaction does not exist on the surface  of the anti-de-sitter space.  thus a black hole is the equivelent of a swarm of interacting particles on the boudary surface of space time. Strings on the boundary area represent particles in the interior space. Strings are chains of gluons. {but one type of gluon chain behaves exactly like our elusive gravitons. Gravity is an emergent condition arising from particle interactions in a gravityless three dimensional world. Thus the holographic corespondence not only links string theory (quantum gravity) to  theories of quarks and gluons it also helps define what the string theory equations must look like.   

[Stormbringer]

Using this model physics does not breakdown in blackholes and statistical mechanics can be used to derive exactly by a different type of math the temperature of the hawking radiation. exactly. Going the reverse diraction the holographic model has been used to deduce the shere viscosity of a quark-gluon plasma. This prediction was confirmed by experiments using the RHIC at brookhaven national laboratory. obvioslt there is something to it when it can make predictions which turn out to be true, however anti De-sitter space is not as complex as our space time and extending the ADS to our level of complexity involves such complexity of math that it is currently impossible to accomplish.

[Stormbringer]

OK, who's the hater who downgraded my thread's rating? 

[prometheus]

OK, who's the hater who downgraded my thread's rating? 

Not me man, I've had a great time with this thread!