[ExI] Expansion of the Universe

[spike]

-----Original Message-----
From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of BillK

>...The expansion of the universe seems to be driven by dark energy
(whatever that is!).

So there are three options.
1) Indefinite expansion. Dark energy carries on expanding as we see it
operating now.
This is the favourite option as there is no known reason for it to change
behaviour.
2) Big Crunch. Dark energy reverses and starts collapsing the universe back
to a point.
3) Big Rip. Dark energy gets stronger and keeps on increasing.
This scatters everything quicker and quicker.

BillK
_______________________________________________

BillK, this all brings back memories from Spring of 1998, when the High-Z
report came out reporting the evidence supporting the inflation model of the
universe.  I and those who follow that sort of thing agreed this isn't what
we ordered at all, and hoped the report was wrong.  As I recall, within just
a couple weeks, Saul Perlmutter's team reported similar results, which was
discouraging for those of us who thought the universe was either flat or
closed.  Most of us thought then that it was probably flat, but hoped like
hell it was closed, so that we could imagine it all coming back together
again and again, an infinite number of times.

Needless to say, it was a shock to hear that the top cosmologists were
concluding the universe is open.  Perlmutter was a highly regarded
cosmologist already by that time although he was a young guy, still in his
30s or around 40 perhaps.  One of the guys at work claimed to know Permutter
personally, and invited him to speak at a local Lockheed astronomy seminar.
He accepted, and gave us a terrific pitch.  That was in 1998 but I have
clear memories of that talk.  I couldn't find any flaws in it anywhere, even
though I didn't like the conclusion and still don't.  It would bring me
enormous joy to learn that there was some systematic error, and that the
universe is closed.

Perlmutter mentioned the Big Rip notion at that time, although he didn't
call it that.  It was the notion of accelerating inflation.  I reeeeaaalllly
hoped he was mistaken on that one, and still hope so.  Nothing against Saul
Permutter at all (he seems like such a pleasant person, and scary smart,
astronomy's version of Anders Sandberg) but I do hope he and the others
missed something that reverses their grim conclusions.  Permutter is not a
tranhumanist, so he doesn't understand why it is such a sad thing that the
Big Rip is only twenty billion years from now.

spike