FRW Derivation History: Acker's Questions Answered

[Acker]

Hello All,

I wondered if anyone could fill in some details about the timeframe of FRW derivation.
Was it derived to purposefully address the expansion of a universe? and if so, how did
anyone know about this prior to Hubble's observations?
Or was it derived for some other purpose and then applied after Hubble?
I am keenly interested in this and would love to hear any information in this forum
regarding the reasons for deriving this cosmological equation.

Regards
Acker

edit. And was it derived using Newton before Einstein's gr or between gr and Hubble's observations?

 

[phinds]

Are you not familiar with Wikipedia?

http://en.wikipedia.org/wiki/Friedmann–Lemaître–Robertson–Walker_metric

 

[Acker]

Thank you Phinds, for your thoughts on the matter.

When I am asked something, I tend to refrain from handing someone an encyclopedia
and quipping 'go look it up'.

It is such a relief that we can always turn to wikipedia for definitive discourse.


Best regards
Acker

 

[phinds]

Folks who come here with questions are expected to have made at least some minimal attempt to do their own homework first, and it sounded as though had not done so.

I refer you to:

https://www.physicsforums.com/blog.php?b=3588

 

[sardar]

Hello Acker,

The Friedmann–Lemaître–Robertson–Walker (FRW) cosmological model was first derived by Alexander Friedmann in 1922 and independently by Georges Lemaître in 1927. This model describes the expanding universe and is based on Einstein's theory of general relativity.

At the time of its derivation, the concept of an expanding universe was not widely accepted or understood. However, Friedmann and Lemaître were able to derive this model by using Einstein's equations and applying them to the entire universe, rather than just the local region as was previously done.

It is important to note that Hubble's observations of the redshift of galaxies in 1929 provided strong evidence for an expanding universe, providing support for the FRW model. However, the model was not derived specifically to address the expansion of the universe. It was more of a natural consequence of applying general relativity to the entire universe.

Furthermore, the FRW model was derived using general relativity, not Newtonian mechanics. Einstein's theory of general relativity was published in 1915, before Hubble's observations in 1929. So the FRW model was derived using general relativity before Hubble's observations.

I hope this helps to answer your questions about the history and derivation of the FRW cosmological model. If you have any further questions, please don't hesitate to ask.

Best regards,