On 1/25/2012 11:04 PM, Stephen P. King wrote:
Hi John,
On 1/25/2012 11:57 PM, John Clark wrote:
On Tue, Jan 24, 2012 at 11:27 PM, Stephen P. King <stephe...@charter.net
<mailto:stephe...@charter.net>> wrote:
Stephen P. King <stephe...@charter.net <mailto:stephe...@charter.net>> Wrote:
> A "constant" that Einstein himself called the "greatest mistake of
his life". The problem is that one can add an arbitrary number of such
scalar field terms to one's field equations. Frankly IMHO, it is more
"something from nothing" nonsense.
Yes, it amounted to a repulsive effect that came from space itself, and
you can set that constant to anything and mathematically the field
equations of General Relativity would still work. Originally Einstein
saw no physical reason for that additional complication so he set it to
zero. But then he noticed that if it was zero the universe could not be
stable, it must be expanding or contracting; at the time everybody
including Einstein thought the universe was stable so he set it to a non
zero value and the cosmological constant was born. However just a few
years later Hubble found that the universe was expanding, so Einstein
thought the cosmological constant no longer had a purpose and said that
changing it from zero was the greatest mistake of his life.
Interesting. That is not quite the the story that I recall from Abraham Pais'
biography of Einstein, but I might be misremembering.
You probably remember correctly. Einstein originally set the CC non-zero in order that
the universe could be in static equilibrium because that was the empirical conclusion at
the time. Shortly after he published, De Sitter pointed out that the universe would be in
unstable equilibrium. It is true that the discovery of the Hubble expansion caused the CC
to be otiose. Einstein then called it his greatest blunder because if he had realized he
couldn't use it to make a static universe he might have predicted the Hubble expansion.
Brent
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To post to this group, send email to everything-list@googlegroups.com.
To unsubscribe from this group, send email to
everything-list+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/everything-list?hl=en.
