# How far does space-time bend out in space?

1. Sep 9, 2011

### johann1301

When looking at earths ability to curve space-time; how far does these curves go? can they theoretically be registered at the edge of the universe?(just an infinite small amount of course).?

i suppose i could just ask if earths gravity stretches everywhere in the universe? or.. is there a place in the universe where there is no gravity?

2. Sep 9, 2011

### Fredrik

Staff Emeritus
You guessed it. The closest thing we have to a direct answer to your question is the Schwarzschild solution. It describes a universe that's completely empty except for a single non-rotating, spherically symmetric distribution of mass with zero electric charge. In that solution, no part of spacetime is exactly flat. Curvature goes to zero as the distance from this object goes to infinity, but it never actually reaches zero.

Edit: I have corrected the mistake that Passionflower quoted in #4.

Last edited: Sep 9, 2011
3. Sep 9, 2011

### johann1301

Thank you for a good answer!

I also wonder;

lets say:
1. There are two spheres that both have the same density as earth.
2. One sphere is twice the size as the other.
3. The bigger sphere would then have twice the mass.

would the effects of gravity in the big one be twice as big as the effects of the smaller one? for example; would time go half as fast in the bigger sphere?(relative to the other sphere of course) (time dilation) I guess Im asking if every effect of gravity is completely proportional?

Hope the question made some sense;)

4. Sep 9, 2011

### Passionflower

You mean as it goes to infinity?

5. Sep 9, 2011

### Fredrik

Staff Emeritus

Yes, of course.

Those are questions that would take me some time to answer, so I'll leave them for someone else. I'm sure there's someone who has worked with the Schwarzschild metric recently, who can answer in a tenth of the time it would take me.

Last edited: Sep 9, 2011