5
votes
2answers
144 views

What is the meaning of the “expansion of space”?

When we say that "the space between galaxies is expanding," what do we really mean? For instance, if I think of space as being a Cartesian grid, then when space expands should I think of it as adding ...
11
votes
2answers
496 views

How is it possible the universe expanded faster than the speed of light during inflation?

In a documentary written in collaboration with Stephen Hawking, the narrator (supposedly Stephen Hawkings) says that by the time the cosmos was 10 minutes old, it had already expanded thousands of ...
5
votes
3answers
287 views

What does string theory say about the metric expansion?

Specifically, what happens to those small intertwined hidden dimensions? Do those expand too?
3
votes
3answers
161 views

What would be the effect on gravity if space expanded at > $c$?

If space were to expand at > $c$ (as in inflation) would that mean gravity would no longer have any effect on the curvature of space, since gravity can only propagate at $c$?
4
votes
1answer
453 views

Additional merits to Wetterich's “Universe without expansion” compared to standard cosmological redshift interpretation?

A recent news item in Nature promotes Wetterich's preprint "A Universe without expansion". All sounds very exciting but hard to judge for non-experts. As I understand from the Nature's article, the ...
2
votes
0answers
110 views

Cosmic Inflation: Lower Expansion Rate with than without?

When I read the Cosmic Inflation diagram at https://en.wikipedia.org/wiki/File:Horizonte_inflacionario.svg which I rotated to make it readable: where the Hubbleradius, and therefore also the ...
0
votes
3answers
148 views

Acceleration in the rate of expanansion of the universe due to weakening gravity?

Could the acceleration in the rate of expansion of the universe be due to the weakening of gravitational forces, as the distance between objects continues to increase?
0
votes
1answer
782 views

How does an inflationary universe solve the Flatness Problem, Horizon Problem and Monopole Problem? [duplicate]

Possible Duplicate: What is the evidence for Inflation of the early universe? I am reading some public science books on inflationary universe, e.g. The Inflationary Universe by A. Guth. ...
2
votes
0answers
113 views

Can decompactification explain the inflation of the early universe?

I've just reread chapter 11 of this book where it is explained among other things, that our four dimensional universe could be unstable concerning a decompactification transition, since potential ...
0
votes
1answer
230 views

Is the FRW metric describing the shape of the universe or the shape of the expansion applied to the universe?

Is it (the output, i.e, spherical, flat, hyperbolic) describing the physical shape of the universe and its curvature at any given instance of time or is it describing the shape of the expansion ...
3
votes
1answer
248 views

Curvature, Omega, the Flatness problem, and the evolving shape of the universe

I'm a little confused by this: http://en.wikipedia.org/wiki/Flatness_problem Which seems to imply the universe is more curved now than it was soon after the Big Bang. Look at the graph on the right ...
2
votes
1answer
77 views

Cosmic bubble collision

I'm reading this review right now. The claim seems to be that when you have an expanding "false vacuum", finite size bubbles form due to phase transition (cause by finite action instantons) (which, in ...