[extropy-chat] WMAP Results - Cosmology Makes Sense
russell.wallace at gmail.com
Sun Mar 19 20:38:20 UTC 2006
On 3/19/06, Lee Corbin <lcorbin at tsoft.com> wrote:
> His other big cow was the use of the term "dark energy", with
> which I totally agree with him. He complained: "I knew what the
> cosmological constant was *long* before the nineties, when this
> awful term was coined. And that's all it is!"
I disagree. "Cosmological constant" is a term for the effect (without
comment on the cause); "dark energy"/"vacuum energy" is a postulated cause
of that effect.
Susskind in "The Cosmic Landscape" explains that the following
> three items are just different terms for exactly the same thing:
> vacuum energy = cosmological constant = dark energy
> (Of course, the lambda cosmological constant is just the constant
> added to the right part of Einstein's equation, but it serves
> exactly the same function. The nice term "vacuum energy" on the
> other hand, is very appropriate for depicting the concept of
> the on-going virtual particle creation/destruction within each
> cubic meter of space.)
Er, "dark energy" and "vacuum energy" mean basically the same thing, if you
think "vacuum energy" is a nice term, what have you got against "dark
Though I'm still curious about that business of gravity becoming repulsive
when the relative speed gets to 0.57c (quoting the figure from memory,
mightn't be exact), I'm curious as to whether that might explain at least
some of the accelerating expansion.
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