Why does redshift indicate that space-time is expanding

[LSulayman]

Since nobody answered my last question I''l try it this way:

Why does redshift indicate that space-time is expanding and not that galaxy's are just flying away from each other?

 

[Kracatoan]

Its the fact that the further away it is, the faster a galaxy appears to be travelling, and this points towards space-time itself expanding, rather than the galaxies moving away and nothing else.

 

[russ_watters]

Since nobody answered my last question I''l try it this way:

Why does redshift indicate that space-time is expanding and not that galaxy's are just flying away from each other?

What you suggest requires that the universe have an edge and a non uniform distribution of galaxies and neither are observed.

 

[LSulayman]

What you suggest requires that the universe have an edge and no such edge is observed.

How come? Maybe this is something we know now but when Hubble presented his observations of redshift people did not know. (I think)

 

[russ_watters]

What does that have to do with anything? (...and see my late edit...)

 

[LSulayman]

What you suggest requires that the universe have an edge and a non uniform distribution of galaxies and neither are observed.

Why do you have to observe these things in order to explain that redshift is not from expanding space-time but from galaxy's flying away from each other?
Or do I need heavy phisics to understand (I'm not a physisist or stronomer so)?

I'm trying to understand what made people (Hubble) back then think that the redshift was because of expanding space-time, that's why I asked.

 

[russ_watters]

Btw, you'll need to be more patient - this place isn't continuously staffed and activity can be highly variable.

 

[Calimero]

Why do you have to observe these things in order to explain that redshift is not from expanding space-time but from galaxy's flying away from each other?
Or do I need heavy phisics to understand (I'm not a physisist or stronomer so)?

I'm trying to understand what made people (Hubble) back then think that the redshift was because of expanding space-time, that's why I asked.

LS, you should search this site for threads adressing cosmological redshift vs doppler redshift. On small enough scales they can both give same results, on large scales doppler redhift gives wrong numbers, although there are ways of treating cosmological as doppler, it only unnecessary complicates things.