Does Space Expand? What Do You Think?

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In summary: In this theory, distance is not absolute, but rather depends on the curvature of spacetime and the observer's frame of reference. The proper distance, as mentioned before, is the length between two events in a frame of reference where they occur simultaneously. However, in GR, this distance can change over time as the curvature of spacetime changes. This allows for the possibility of objects to move away from each other at a rate faster than the speed of light, as long as they are not in the same inertial frame of reference. This is why, in an expanding universe, distant galaxies can appear to be moving away from each other at speeds greater than the speed of light
  • #176
The idea of expanding space seems to me to be precicely as strange as in-falling space in the vacinity of black holes. One is simply the reverse of the other!

Since the big bang appears to be a singularity that for some reason became disrupted and exploded outwards, it would follow that space would expand in a collapsing or diminishing gravitational field. The further out the space is, the faster it expands - Just as with a black hole the further in the faster it shrinks.

This seems to me to be a better explanation than dark energy for the accelerating expansion - not least because we don't have to look for anything new!

And yes it can go faster than light because the speed of space itself is not limited in GR.
 
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  • #177

Equation of State:
[tex]P(r) = -\rho(r) c^2[/tex]

Inflationary metric:
[tex]ds^2 = - (1 - \Lambda r^2) c^2 dt^2 + \frac{1}{1 - \Lambda r^2} dr^2 + r^2 d\Omega^2[/tex]

If space is still expanding, then would this metric also still be applicable in the Universe at present time?

Reference:
Cosmic inflation - space expands - Wikipedia
 
Last edited:
<h2>1. Does space really expand?</h2><p>Yes, according to current scientific theories and observations, space does expand. This expansion is known as the expansion of the universe.</p><h2>2. How does space expand?</h2><p>Space expands through a process known as cosmic inflation, which is believed to have occurred shortly after the Big Bang. This inflationary period caused the rapid expansion of the universe and continues to this day, although at a much slower rate.</p><h2>3. What evidence supports the idea of space expanding?</h2><p>There are several pieces of evidence that support the idea of space expanding. One of the most notable is the observation of galaxies moving away from each other, which is known as the Hubble's law. Additionally, the cosmic microwave background radiation, leftover radiation from the Big Bang, also supports the idea of cosmic inflation and the expansion of space.</p><h2>4. Is there a limit to how much space can expand?</h2><p>The current understanding is that space does not have a limit to how much it can expand. However, the expansion rate may change over time, and there are theories that suggest that the expansion may eventually slow down or even reverse.</p><h2>5. How does the expansion of space affect objects within it?</h2><p>The expansion of space does not directly affect objects within it. This is because the expansion happens at a much larger scale than the objects in our everyday lives. However, the expansion does have an impact on the distance between objects, causing them to move further apart over time.</p>

1. Does space really expand?

Yes, according to current scientific theories and observations, space does expand. This expansion is known as the expansion of the universe.

2. How does space expand?

Space expands through a process known as cosmic inflation, which is believed to have occurred shortly after the Big Bang. This inflationary period caused the rapid expansion of the universe and continues to this day, although at a much slower rate.

3. What evidence supports the idea of space expanding?

There are several pieces of evidence that support the idea of space expanding. One of the most notable is the observation of galaxies moving away from each other, which is known as the Hubble's law. Additionally, the cosmic microwave background radiation, leftover radiation from the Big Bang, also supports the idea of cosmic inflation and the expansion of space.

4. Is there a limit to how much space can expand?

The current understanding is that space does not have a limit to how much it can expand. However, the expansion rate may change over time, and there are theories that suggest that the expansion may eventually slow down or even reverse.

5. How does the expansion of space affect objects within it?

The expansion of space does not directly affect objects within it. This is because the expansion happens at a much larger scale than the objects in our everyday lives. However, the expansion does have an impact on the distance between objects, causing them to move further apart over time.

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