In a message dated 2/16/01 9:21:26 AM Eastern Standard Time, DMoore@GDA.ORG
writes:
<< I believe that Einstein added the cosmological constant to his equations to
account for the fact that the universe was not collapsing upon itself
because of gravity, not because his theory predicted an expanding universe.
Am I wrong on this point?
>>
Apparently when some of the equations of GR are solved you get a constant of
integration which we know as the cosmological constant. However the effect of
this constant is to generate a gravatational repulsion at very large
distances. With this constant at zero you either end up with a contracting
universe or if it is not contracting then the attractive gravitational force
must be countered by the inertia of an expanding Universe. Therefore if CC is
zero the Universe must be expanding or contracting. Einstein though the
Universe must be static. So he used a positive cosmological constant to
balance the cumulative attractive force of gravity to get a static Universe.
Of course this whole scheme is unstable. You would only get a
static Universe at one particular scale factor. If the scale were larger than
the critical value the Universe would expand and if the scale factor was
smaller than the critical value it would contract. One wonders why someone of
Einstein's caliber didn't see this.
When Einstein finally accepted the fact that the Universe was
expanding, he set CC to zero and called it his biggest mistake.