View Single Post
Jan20-06, 01:31 AM
P: 167

Quote Quote by pervect
There's another way of saying something similar that is more in the spirit of true GR and perhaps simpler. The net gravitational effect of a spherically symmemtric expanding shell of matter can be shown to be zero inside the shell.

The cosmological horizon (assuming it exists, which means assuming that the universe's expansion is accelerating and will continue to accelerte) is thus not due to the effects of the matter outside - it is due to the effects of the matter (and dark energy) inside the horizon.
Aparrently you may have missed this point:

Quote Quote by ubavontuba
My concept is that to the observer, the universe having seemingly been expanding at relativistic speed from any given point, the perceived black hole "shell" should not act inside like the interior gravitational effects of a normal gravitational sphere. This is because the mass is receding at near light speed in either perceived direction (sort of like shining two flashlights in opposite directions).

That is that from the standpoint of the observer, the energy and mass at the perceived edge of the universe on his left, let's say, is in a noncontiguos reference frame from the matter and energy on his right.

So, all the matter on his right, let's say, is going to be effected more and more by the matter at the perceived edge on his right, in a relationship to distance. The closer it is to the observer, the less it is thusly affected and conversely, the farther away it is, the faster it will seem to be accelerating outward (generally speaking).

As the universe expands, this effect should be perceived by the observer as an acceleration of the expansion of the universe. Ergo, as "dark energy." This is because the receding walls allow there to be more space for this effect to take place in, and therfore everything (including perceived motion) must seemingly get bigger (faster) too.
Do you see? We're not in a normal gravitational sphere in this case. All radii are noncontiguos (increasingly so with distance). In the normal gravitational sphere to which you refer, it's all in a single/contiguous reference frame. (Of course this is assuming that gravity truly propagates at the speed of light.)