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From: weemba@brahms.BERKELEY.EDU (Matthew P. Wiener)
Newsgroups: net.astro
Subject: Re: Re: StarDate: March 14 A Toast to Einstein
Message-ID: <12467@ucbvax.BERKELEY.EDU>
Date: Mon, 17-Mar-86 21:52:51 EST
Article-I.D.: ucbvax.12467
Posted: Mon Mar 17 21:52:51 1986
Date-Received: Wed, 19-Mar-86 01:01:15 EST
References: <12382@ucbvax.BERKELEY.EDU> <158@rtech.UUCP>
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Reply-To: weemba@brahms.UUCP (Matthew P. Wiener)
Organization: University of California, Berkeley
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In article <158@rtech.UUCP> jeff@rtech.UUCP (Jeff Lichtman) writes:
>>>Today we celebrate the birthday of Albert Einstein -- the first person
>>>to suggest that space can be curved.
>> 
>>    I think this was Gauss, Debbie. Einstein suggested that space-time was
>> curved, which is not the same thing.
>
>Gauss, Lobachevsky, et al. studied curved spaces as mathematical objects, not
>as models of reality.  As far as I know, Einstein was the first to use non-
>Euclidean geometry to describe real space.

Gene's assertions are correct.  In particular, the distinction between
curved space and curved space-time is important, but usually ignored in
popular accounts.

Gauss measured the angles of a large triangle in Germany to see whether or
not the three angles added up to 180 degrees experimentally.  He concluded
that one could not yet tell.  Einstein was the first to *successfully* use
non-Euclidean geometry in describing the mathematics of space-time.  On the
way to his general theory of relativity, he had tried a theory which just
involved the curvature of space, still treating time as something separate.
This theory gave the correct prediction for the precession of Mercury's orbit,
but gave a value for the deflection of light by the sun one-half of the
correct value.

Riemann in the mid 19th century had tried using his geometry to base a theory
of gravitation on.  He missed the importance of space-time as opposed to just
space.  My memory is fuzzy on failed theories of gravitation, but I seem to
recall Ni in 1913 proposed a theory of relativity involving curved space-time.
He had the right idea but the wrong field equations.

We all hear about the success stories in the history of science, but there
are a lot of fascinating close misses.

ucbvax!brahms!weemba	Matthew P Wiener/UCB Math Dept/Berkeley CA 94720