In article ,
Starblade Darksquall wrote:
There seems to be a very big split between those who beleive that
gravity is a force between two bodies mediated by the graviton 2-boson
and can be unified with the other forces, and those who beleive that
gravity is the bending of timespace, and that freefall can be taken to
be a proper reference frame.

It helps first to figure out what a particle is. And quantum field theory
is a theory of fields. The electromagnetic force is carried by photons.
But what are photons? They are quantizations of the electromagnetic
field. But the particles in this context are not little billiard balls.
And electrons are quantizations of the Dirac field, and other elementary
particles are quantizations of other fields. Just as phonons are normal
modes that groups of atoms can have. There's a natural particle
interpretation in friendly spacetimes like the one we live in, but not in
general. The particle behavior comes from the field by deBroglie's
relation; for a given wavelength the energy must be some E, or 2*E, or
3*E, etc., but nothing in between--photoelectric effect or, if there's
boundary conditions, quantized energy levels as the orbitals in an atom.
And all that energy is dumped somewhere as a quantum, rather than being
distributed here and there, which brings us to that "collapse of the wave
function" thing that nobody really knows how to interpret.

So there's no real dichotomy between gravitons and curved spacetime. It's
just an insistence on applying deBroglie's relation to spacetime
curvature, too.
--
"Is that plutonium on your gums?"
"Shut up and kiss me!"
-- Marge and Homer Simpson

"Gregory L. Hansen" wrote in message
...
| In article ,
| Starblade Darksquall wrote:
| There seems to be a very big split between those who beleive that
| gravity is a force between two bodies mediated by the graviton 2-boson
| and can be unified with the other forces, and those who beleive that
| gravity is the bending of timespace, and that freefall can be taken to
| be a proper reference frame.
|
| It helps first to figure out what a particle is. And quantum field theory
| is a theory of fields. The electromagnetic force is carried by photons.
| But what are photons? They are quantizations of the electromagnetic
| field. But the particles in this context are not little billiard balls.
| And electrons are quantizations of the Dirac field, and other elementary
| particles are quantizations of other fields. Just as phonons are normal
| modes that groups of atoms can have. There's a natural particle
| interpretation in friendly spacetimes like the one we live in, but not in
| general. The particle behavior comes from the field by deBroglie's
| relation; for a given wavelength the energy must be some E, or 2*E, or
| 3*E, etc., but nothing in between--photoelectric effect or, if there's
| boundary conditions, quantized energy levels as the orbitals in an atom.
| And all that energy is dumped somewhere as a quantum, rather than being
| distributed here and there, which brings us to that "collapse of the wave
| function" thing that nobody really knows how to interpret.
|
| So there's no real dichotomy between gravitons and curved spacetime. It's
| just an insistence on applying deBroglie's relation to spacetime
| curvature, too.

I kind of like Bilge's description that gravitons are carriers of spacetime
geometry.

FrediFizzx

"FrediFizzx" wrote in message ...
"Gregory L. Hansen" wrote in message
...
| In article ,
| Starblade Darksquall wrote:
| There seems to be a very big split between those who beleive that
| gravity is a force between two bodies mediated by the graviton 2-boson
| and can be unified with the other forces, and those who beleive that
| gravity is the bending of timespace, and that freefall can be taken to
| be a proper reference frame.
|
| It helps first to figure out what a particle is. And quantum field theory
| is a theory of fields. The electromagnetic force is carried by photons.
| But what are photons? They are quantizations of the electromagnetic
| field. But the particles in this context are not little billiard balls.
| And electrons are quantizations of the Dirac field, and other elementary
| particles are quantizations of other fields. Just as phonons are normal
| modes that groups of atoms can have. There's a natural particle
| interpretation in friendly spacetimes like the one we live in, but not in
| general. The particle behavior comes from the field by deBroglie's
| relation; for a given wavelength the energy must be some E, or 2*E, or
| 3*E, etc., but nothing in between--photoelectric effect or, if there's
| boundary conditions, quantized energy levels as the orbitals in an atom.
| And all that energy is dumped somewhere as a quantum, rather than being
| distributed here and there, which brings us to that "collapse of the wave
| function" thing that nobody really knows how to interpret.
|
| So there's no real dichotomy between gravitons and curved spacetime. It's
| just an insistence on applying deBroglie's relation to spacetime
| curvature, too.

I kind of like Bilge's description that gravitons are carriers of spacetime
geometry.

FrediFizzx

Okay, I understand now. So, how are relativistic effects 'carried'?
And why is force distributed across mass?

Do you think there's a relation between mass's gravitational
properties and its inertial properties?

(...Starblade Riven Darksquall...)

Starblade Darksquall:
"FrediFizzx" wrote in message
...

I kind of like Bilge's description that gravitons are carriers of
spacetime geometry.

FrediFizzx

Okay, I understand now. So, how are relativistic effects 'carried'?

Don't get too carried away with the description. It's just a way
to try and handwave the basic plot.

And why is force distributed across mass?

Gravitons are not a good way to describe macroscopic phenomena any
more than photons are a good way to describe why your hand doesn't
go through a wall and the latter case is much easier. The gravitational
interaction couples to itself, so it's not a simple picture of particle
exchange, like E&M.

Do you think there's a relation between mass's gravitational
properties and its inertial properties?

Since the equivalence principle holds to the degree of precision so far
accessible to experiments, that would have to be a yes. Don't forget,
there are weak, strong and electromagnetic interactions. The mass of a
proton is the same regardless of which of those forces one uses to measure
it (or at least it's possible to define a mass common to all of those
interactions as opposed to some bizarre alternative that I find hard to
picture). That did not have to be the case. The fact that it is, gives a
pretty good argument for special relativity being correct, at least in the
energy regime that is experimentally accessible. If gravity is just a
description of inertial motion, then gravitational mass and inertial mass
are equivalent. If instead, one considers gravity to be a force, then
there is no reason to assume that the gravitational interaction would
treat mass any differently than the the other forces, especially, since
the mass itself is the gravitational "charge".