Is expansion of space relative?

In summary, the conversation discusses the possibility of some spaces expanding or contracting more than others, and if general relativity can support the idea of space shrinking faster where there is a higher density of matter. It is argued that on the scale of the universe, any variation would be negligible and that the expansion of space is influenced by the density of matter. There is a contradiction between the idea of spacetime being defined by matter and the universe as a whole expanding, raising the question of what is causing this expansion.
  • #1
kmarinas86
979
1
Could it be that some spaces are expanding more than others?

What about the reverse? Could it be that some parts of space are contracting more than others? Is it relative?

Could GR support the notion that space where matter exists is shrinking faster than space far away from matter?

Would this still conserve the cosmic background radiation? Would it still lead to its redshift?
 
Physics news on Phys.org
  • #2
kmarinas86 said:
Could it be that some spaces are expanding more than others?

What about the reverse? Could it be that some parts of space are contracting more than others? Is it relative?

Could GR support the notion that space where matter exists is shrinking faster than space far away from matter?

Would this still conserve the cosmic background radiation? Would it still lead to its redshift?

On the scale that needs to be considered the universe, to use a non-technical term, is so samey that you'd expect any variation will be negligible.
 
  • #3
kmarinas86 said:
Could it be that some spaces are expanding more than others?

What about the reverse? Could it be that some parts of space are contracting more than others? Is it relative?

Could GR support the notion that space where matter exists is shrinking faster than space far away from matter?

Would this still conserve the cosmic background radiation? Would it still lead to its redshift?

I carn't see why not - area's of space with a high density of matter would be highly curved and so 'resist' spacetime expansion. Space is defined by the distance between objects, its not an independent entity, so the relative space between two exploding stars is expanding, whereas the space around a collapsing neutron star is collapsing. I'm not sure if this applies for the Universe as a whole, since its expansion derives from the energy of the big-bang.
There does seem to be a contradiction though, because spacetime is not a permanent background, it is defined by the properties of matter - at the same time the Universe is expanding. What is doing the expanding?
 

1. What is the expansion of space?

The expansion of space refers to the phenomenon where the distance between galaxies and other astronomical objects is increasing over time. This expansion is thought to be caused by dark energy, a mysterious force that is counteracting the force of gravity.

2. Is the expansion of space relative?

Yes, the expansion of space is relative. This means that the rate of expansion can vary depending on the observer's reference frame. For example, an observer in a galaxy far away would see a different rate of expansion compared to an observer in our Milky Way galaxy.

3. How do scientists measure the expansion of space?

Scientists use a variety of methods to measure the expansion of space. One common method is using the redshift of light from distant galaxies. This occurs because the stretching of space causes the wavelength of light to increase, making it appear more red. By measuring the amount of redshift, scientists can determine the rate of expansion.

4. Is the expansion of space constant?

No, the expansion of space is not constant. In fact, scientists have observed that the rate of expansion is increasing over time. This means that the distance between galaxies is increasing at a faster rate now compared to billions of years ago.

5. How does the expansion of space affect the universe?

The expansion of space has a significant impact on the universe. As the distance between galaxies increases, it also affects the growth and evolution of structures within the universe. It also has implications for the ultimate fate of the universe, with some theories suggesting that the expansion will continue to accelerate until all matter is torn apart.

Similar threads

  • Special and General Relativity
2
Replies
48
Views
1K
  • Special and General Relativity
Replies
2
Views
875
  • Special and General Relativity
Replies
7
Views
1K
  • Special and General Relativity
Replies
5
Views
736
  • Special and General Relativity
Replies
4
Views
1K
  • Special and General Relativity
Replies
32
Views
724
  • Special and General Relativity
Replies
7
Views
2K
  • Special and General Relativity
Replies
17
Views
1K
Replies
6
Views
1K
  • Special and General Relativity
Replies
3
Views
770
Back
Top