On Mon, Mar 10, 2025 at 2:14 AM Alan Grayson <agrayson2...@gmail.com> wrote:
*> **Without a CC, or equivalently setting it to zero, don't we get a > universe which is in UNSTABLE equilibrium, like balancing a pencil of its > writing tip, * > *No. Einstein knew if the cosmological constant was zero then the universe would keep expanding forever and no small change, or even a supernova, could alter that situation, certainly a butterfly in Paraguay flapping its wings couldn't. So things would not be static but they would be in a state of stable equilibrium. However if the cosmological constant was not zero, as Einstein's reluctantly revised and less beautiful equations said, then the universe could be static but the equilibrium would be unstable (although that instability was not discovered until 13 years later by Arthur Eddington), if that butterfly flaps its wings too much then the universe will either start to expand or contract. * *So Einstein was trying to fix a problem that didn't exist, and even if it had existed it was a very poor way of fixing it, so it's no wonder that Einstein called it his "greatest blunder". Fortunately a**s soon as Hubble discovered that the universe was expanding Einstein immediately dropped the CC idea and he went back to his original beautiful equations. * * > so the universe expands or contracts in a very short time interval?* > *Forever is not a very short time interval. * > * > **why would he choose a positive CC? AG * > *The short answer is because Einstein was desperate. He knew that however beautiful a theory is, if it conflicts with observation then it's wrong, and in 1915 he thought General Relativity did conflict with observations, so he reluctantly tacked on another term even though he thought it made the equation less beautiful. But it turned out the 1915 observations were wrong, not the theory.* * John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* tge -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAJPayv26ATSmGKVKbtNbxR5NkPjcrEx00Jm04qYRb%3DpzaZrt8g%40mail.gmail.com.
