My question is about gravities relationship with the expansion of the universe.

The question is that could empty space be curved?

By this I mean either:
1) Can there be a gravitational field that permiates the universe as a whole. Maybe from the sum of small ( negligable effects ) multiplied over the numerous massive of the universe, dark matter, or using brane theory ... a source from outside our brane.
2) That space just has a natural 4d curve to it.


Now for number one above. If all of the matter in the universe has an effect on every single point in the universe ( even if it is negligable ) then at each point all forces would roughly even out so the direction of the gravitational pull would not exist, however the effect of the red shift would work.

Now the questions remains how much gravity would be needed to create the redshift needed for this effect. Since the curvature near a massive object greatly offsets the effects of universal expansion, I think the amount of curvature throughout space needed to produce the redshift should be within reason.

My question is how can I calculate the amount of gravity that would be needed?
How can I test this?

nobody?

Doppler shift is easy to understand.
No one seems to understand the cause of gravitational light frequency shift(red or blue).
The answer is in GR but I have never read the answer in words that I can understand.
Maybe it is lost in the incomprehensible maths that is given as an explanation by
people who cannot visualize the reason.
Soon, I think I can make someone explain it to me by asking the right questions.

Why not just say it?.
Because it will be rejected (one more nut on ATM)with little thought but is simple.
It also explains the missing mass without inventing dark matter.

Answer my questions and you will say the answer.

The way I see the gravitational red shift is because of the curvature of space-time. Space actually contracts near gravity. Or rather gravity is the contraction of space-time. So the relative path becomes farther the deeper something is in a gravitational well. Coming out provides a boost of energy. as to conserve the speed of light. The opposite is also true.