In article <ze-dndVfFKFidSTanZ2dnUVZ_vCknZ2d@[EMAIL PROTECTED]
>,
max@[EMAIL PROTECTED]
says...
> bernardZ wrote:
>
> > General relativity was published by Albert Einstein in 1915/16. Albert
> > Einstein only adopted the big bang theory long after trying several
> > other alternatives first.
>
> This is incorrect on several levels.
>
> Hubble first discovered the red****ft of galaxies in 1918, and the Hubble
> law relating red****ft to distance in 1929.
This is a bit of a myth. Hubble already knew of the red****ft earlier. He
that announce that his results confirmed it. They did but not greatly.
> Those resulted in the
> development of the Big Bang theory, so there was no such thing at the
> time that Einstein was developing general relativity.
???
> Indeed, at the time, the conventional wisdom was that the Universe was
> finite in size and static and had been around forever. However, when
> applying general relativity to cosmology, Einstein discovered that his
> new theory predicted dynamic cosmologies: expanding or contracting
> ones, but not static ones. Instead of going with what his theory
> predicted, Einstein added a fudge factor, the cosmological constant, so
> that his theory could result in static universes. Not paying attention
> to what his theory was telling him and introducing the fudge factor was
> what he called the greatest "blunder" of his life. (Though now we think
> the cosmological constant is still relevant for other reasons, due to
> dark energy.)
>
Agree. At the beginning of GR Einstein was committed to the static
universe. He found a dubious solution in the cosmological constant. It
was after that really with Friedman that an expanding universe starts to
appear in GR.
> > Clearly Einstein never saw that concept of an expanding spacetime is
> > necessary for GR to be correct.
>
> No one said it did. But it is certainly true that general relativity
> predicts dynamic cosmologies, and Einstein tried to shoe-horn it into a
> static version, instead of being able to triumphantly declare Hubble
> expansion as the first and foremost prediction of his new theory.
>
I doubt he even knew of Hubble work then although he probably knew of
the early works on the red ****ft.
Interestingly one problem that bugged Newton was that his model of the
universe was unstable too. Under Newtonian mechanics the universe should
collapse. To overcome this problem he also theorized a cosmological
constant which he identified with God.
--
Note change of name. The former owner of my sig Bernard Z wants it back.
Reckons his posts and mine are getting mixed up.
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