On Tue, Jan 24, 2012 at 11:27 PM, Stephen P. King <stephe...@charter.net>wrote:
Stephen P. King <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. In act 2 people working with quantum mechanics found that empty space should indeed have a repulsive effect, but the numbers were huge, gigantic astronomical, so large that the universe would blow itself apart in far far less than a billionth of a nanosecond. This was clearly a nonsensical result but most felt that once a quantum theory of gravity was discovered a way would be found to cancel this out and the true value of the cosmological constant would be zero. In act 3 just a few years ago it was observed that the universe is was not just expanding but accelerating, so now theoreticians must find a way to cancel out, not the entire cosmological constant, but the vastly more difficult task of canceling it all out EXCEPT for one part in 10^120. There are only about 10^90 atoms in the observable universe. John K Clark -- 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.
