The age of the universe vs. the speed of light

In summary, the conversation revolves around the concept of inflation and the expansion of space in the early universe. Dr. Hawking's statement about the rapid expansion of the universe shortly after the big bang is discussed, along with the idea that this expansion is what causes the observed redshift and increasing distance between objects. The conversation also touches on misconceptions about superluminal expansion and the role of light in measuring speed in relation to space. References to additional resources for understanding inflation and expansion are provided.
  • #36
As to whether or not galaxies are moving through space or space is expanding and carrying them apart, GR is indifferent. Keep in mind that GR solutions are 4D and multiple spatial foliations are possible. If you choose the spatial hypersfcs of homogeniety and isotropy as "space" in FRW cosmology, then the co-moving galaxies are not moving through "space" by definition. If you choose some other spatial hypersfc as "space," then the galaxies are moving through "space" by definition.

When it comes to telling dynamic stories with GR solutions, there are always many options.
 
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  • #37
Drakkith said:
To the best of our knowledge it is not expanding into anything.

I must admit I love these answers, always people hear them for the first time, it makes them (even me) look like a question mark:rolleyes:
 

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