expansion of space

[keepitmoving]

isn`t it a fact that space expands in the absence of gravity? Does that expansion result from the extra dimensions decompactifying into our 3 dimensions in places where there isn`t much gravity (in the space between galaxies)?

[Freeman Dyson]

I don't mean to hijack this thread but is space independent of mass? Is the expansion of space simply the expansion of mass? "Space" is just how we mark it?

I came across this:

If space exists, what is it?

This is the single most important question in modern physics. Einstein himself said that so far as his general relativity is concerned, space ( actually space-time) and the gravitational field are the SAME THINGS. We see it as something that is empty because, in modern language, we cannot see the quantum particles called gravitons out of which it is 'manufactured'.

[edgepflow]

isn`t it a fact that space expands in the absence of gravity? From the point of view of cosmology based on the Friedmann equation, there is a solutions for this:

(a) Universe with no matter and positive cosmological constant. Expansion is exponential and the Hubble Parameter is constant.

(b) Open universe with small or negligible amount of matter will have expansion that is linear with time.