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According to Big Bang theory and The Red shift theory "space" is "expanding". Keeping this notion of "space" as physically something in and of itself(space -time did not exist before The Big Bang); what are the supposed theoretical answers for the omnidirectional expansion of this "fabric"--noting that no matter where you are in the universe "space" is expanding away from you??

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marked as duplicate by Brandon Enright, John Rennie, Kyle Kanos, Jim, Qmechanic Mar 31 '14 at 13:47

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Space itself was once concentrated in an infinitesimally small point. During the Bang of the Big Bang all distances between points got bigger. If you try to measure the expansion of the universe from any point you will draw the conclusion that the expansion started from that point. It seems that the expansion happened everywhere, and nowhere at the same time.

Think of it like this, if space itself was a tiny dot, then the bang happened in all space, its just that that tiny space is now a lot bigger.

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  • $\begingroup$ Is space expanding at the speed of light? $\endgroup$ – Jiminion Apr 1 '15 at 13:13
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    $\begingroup$ @Jiminion It can expand at any speed, depending on the point you are interested. If you look at sufficiently big distances, space seems to expand faster than the speed of light. $\endgroup$ – Constandinos Damalas Apr 1 '15 at 13:16
  • $\begingroup$ Seems is different that actually expanding FTL. $\endgroup$ – Jiminion Apr 1 '15 at 13:18
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Other than noting that galaxies are moving away from us, we have no frame of reference in order to state how the universe is expanding. We would need to be out side the universe in order to get a description.

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  • $\begingroup$ Actually, I'm trying to get a handle on what "space" is. Einstein: "On the basis of the general theory of relativity...space...has no separate existence" and "there is no such thing as empty space, i., e., a space without field. Space-time does not claim existence on its own, but only as a structural quality of the field."(From Relativity, A Einstien, 1961 Crown Pub. pp 154-155) This means we do not yet fully understand what space is. $\endgroup$ – user43558 Mar 31 '14 at 3:51
  • $\begingroup$ We have the CMB. That is quite important. You can define a frame in the Universe which is at rest relative to CMB. The CMB is redshifted, implying the Universe has expanded by roughly a factor of 1100 since the CMB was decoupled. $\endgroup$ – Thriveth Mar 31 '14 at 12:53
  • $\begingroup$ How do you set a reference in the CMB? Also, doesn't the CMB still change with the expanding universe? $\endgroup$ – LDC3 Mar 31 '14 at 13:33
  • $\begingroup$ I don't think this is completely true. I understand space expansion is greater between galaxies than within galaxies. $\endgroup$ – Jiminion Apr 1 '15 at 13:14
  • $\begingroup$ @user43558 That is my understanding as well. Einstein believed space was 'derived' from nearby mass. However, I don't know if this notion is widely believed by present day physicists. I'm starting to think no one really knows what space is... $\endgroup$ – Jiminion Apr 1 '15 at 13:16

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