On 1/25/2014 5:19 AM, Edgar L. Owen wrote:
Brent,
Obviously the space outside a black hole event horizon is warped. That's experimentally
confirmed. My question is HOW does it become warped from the mass inside the black hole
which you now claim doesn't even exist? There must be some cause.
Sure. In the case of a star that collapses to a BH the cause is the matter which became
so compressed that a singularity formed - and then the matter disappeared into it. That's
why the Schwarzschild metrice is a vacuum solution, no matter.
It's much more reasonable to assume the mass that enters a black hole does exist inside
the black hole as it does produce a gravitational effect.
I don't trust your intuition as to what's "reasonable" - and you shouldn't
either.
My question is how that gravitational effect, which must travel at the speed of light,
propagate from the interior of the black hole when nothing else can because it would
have to travel at FASTER than the speed of light to do so?
It doesn't have to propagate. Each bit of matter falling in already had warped the space
around it and as it crosses the event horizon it leaves this bit of warpage outside
contributing to the total of the BH. You've got and 17th century view of gravity as
something that "reaches out and pulls on stuff".
Re your implication of gravitation perhaps not being mediated by force carrying
particles. I think there are a number of reasons to doubt the existence of gravitons.
1. For a flow of gravitons to explain gravity they would all continuously have to flow
in the same direction since gravity acts only in one direction (between masses at
least). That means there would have to be an inexhaustible source of gravitons flowing
from ONLY OUT from every mass. What's the source of that inexhaustible flow?
See above comment.
2. Gravity is the only force that cannot be shielded. Thus if gravitons existed they
would have to flow effortlessly THROUGH everything that exists (NON-interaction) at the
same time they cause gravitational effects (INTERACTION). An apparent contradiction....
3. There is no empirical evidence whatsoever that gravitons actually exist.
That's not quite true. The prediction of slowing of rapidly orbiting double stars due to
energy loss to gravitational radiation has been confirmed by observation. If that
radiation is quantized, which it must be to be consistent with QM, then it consists of
spin-2 bosons, aka gravitons.
4. Gravitons are not part of the Standard Model.
So all and all I think there is plenty of reason to doubt the existence of
gravitons...
Since the theory is non-linear, gravitons are probably just a weak field approximation.
There is also Sakaharov's gravity theory and the entropic gravity theory. Unfortunately
gravity is so weak it's hard to get any experimental evidence for or against these theories.
Brent
Edgar
On Friday, January 24, 2014 10:31:41 PM UTC-5, Brent wrote:
On 1/24/2014 4:41 PM, Edgar L. Owen wrote:
> Brent,
>
> No, my proposed dark matter effect has nothing to do with black holes.
Black holes
are
> caused by accumulations of actual visible matter, not by the Hubble
expansion of
space...
>
> However I do have a question for you. Since gravitational changes
propagate at the
speed
> of light how does the mass inside a black hole produce gravitational
effects
outside the
> black hole? If light can't come out how can gravitational effects come
out?
You are thinking of gravity as mediated by force particles, like photons
mediate the EM
forces. But (at least classically) gravity isn't a force, it's just a
shape of
space and
as I responded to Liz, there's not mass in a black hole, no T_u_v term in
the Einstein
equation. It's a vacuum solution. That's why it doesn't make any
different what
falls in
to create the black hole. The effects outside the event horizon are just
that the
space
is warped there just *as if* the black hole were a massive object.
Brent
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