Rashad wrote:
> Take a deep breath, relax and let the positive energy I'm
> sending your way seep in. Then rewrite the message you lost
> and share it with us. ...
Okay, Rashad. Here ya go. And although this may be wordy, it's a
shortened version! <grin>
Monday night's lecture was a fun one, with Dr. Alan Guth (MIT) speaking
on "Cosmic Inflation and the Accelerating Universe." For those of you
not aware of just who he is, Prof. Guth is the father of inflation
theory, which currently provides the best explanation for the
development and state of our universe. There were a number of TAC'os
attending the lecture, and I sat with a few of the PAS folk, to include
Ken Lum, Bud Wittlin and Alan Adler. The lecture was designed for the
physics layperson, i.e., no math! Well, virtually none.
To highlight the *initial* part of Monday's lecture (inflation), Prof.
Guth first described what lead to the development of his inflation
theory: Big Bang issues associated with "omega" and a "flat" universe.
The universe now appears to be extremely flat, meaning that the mass,
gravity and velocity properties of the universe are balanced between an
open and a closed universe. Omega describes the ratio between the
density of matter in the universe and the theoretical density needed to
make the universe perfectly flat. If omega is greater than 1, we end up
with a closed universe and a Big Crunch coming. If omega is less than
one, then we have an open universe that goes on expanding forever. In a
flat universe - just in case you wondered - the universe continues to
expand without limit, but with the rate of expansion getting closer and
closer to zero as time goes on. Anyway, for the universe to be as flat
as it currently is, Prof. Guth stated the value of omega just one-second
after the Big Bang would have had to be 1 ... to an accuracy of 15
decimal places, an extremely "finely tuned" number, as he described it.
Well, this is what got Prof. Guth thinking and moving ... with his
inflation theory eventually resolving the problem. With inflation, the
universe didn't need to be fine-tuned from the beginning, but would
instead "drive" omega toward 1 all by itself, resulting in a flat
universe. By the way, Prof. Guth reminded everyone that Big Bang
"theory" just describes the aftermath of the Big Bang, but not what the
Big Bang was or how it developed ... or why the universe appears to be
so "uniform." Inflation, however, addresses all of this.
To start, Prof. Guth noted that Quantum theory holds that a vacuum is
subject to quantum uncertainties, so particles materialize into and
vanish out of vacuums ... albeit very quickly. At extremely high energy
levels, theories predict that a form of matter can be created that is
gravitationally repulsive rather than attractive. This matter, which
would have erupted from the primordial vacuum, is called a false vacuum.
When an incredibly small "patch" of this matter formed, no larger than a
billionth of the size of a proton, the false vacuum's unimaginably
strong repulsive gravitational field would have expanded explosively.
The expansion would be exponential, with the region's diameter doubling
every 10^-37 seconds. After a hundred of these doublings - Prof. Guth
said there might have even been more - the "billionth-of-a-proton" sized
region would have grown to the size of a marble. For comparison
purposes, this increase is equivalent to a pea growing to the size of
the Milky Way ... in a tiny fraction of a second! As the region
expanded, its density also remained constant, no "thinning out" at all,
so the total amount of mass in the region increased by an unbelievable
amount. Although the increase in mass seems like a violation of energy
conservation, a "loophole" - the energy of a gravity field itself is
negative, which cancels the positive energy of the matter - keeps the
total energy constant. The expansion of the region also seems to
violate "Einstein's cosmic speed limit," but Prof. Guth noted that even
though the region grew at faster-than-light speed, "no particle within
the region would ever win a race with a beam of light." Inflation ends
because the false vacuum is fundamentally unstable, and decays like
radioactive material - in exponential fashion - characterized by a
half-life. The material decays into ordinary gravitational-attractive
material, where the particles scatter off each other, quickly reaching
thermal equilibrium, which creates that "primordial soup" we all
associated with the Big Bang.
So it looks like the universe was created by a random quantum
fluctuation out of nothing. The item I found most interesting was the
notion that if you add up all the matter (positive) and gravity
(negative) in the universe, they appear to precisely balance one another
... or cancel each other out, as it were. As Prof. Guth described it,
matter plus gravity equals zero. So the universe can be created from
nothing ... because the universe *IS* nothing!
Okay, so for those of you who were there, e.g., David Kingsley, Jeff
Crilly and James Turley - or those of you already in the know, e.g.,
Leonard, Da Weasel and ZZ - did I get this stuff from Prof. Guth
correct? <grin> If not, speak up!
Obviously there was a lot more to all this - the second half of the
lecture went into acceleration, which fits in perfectly with inflation -
but at least this gives you the flavor of it all. Prof. Guth was also
very approachable, and after the lecture I asked him a couple of
questions about the polarization of the cosmic microwave background,
which he answered and expanded upon. Stanford's own Andrei Linde, an
incredible cosmologist in his own right, finally came over to rescue
Prof. Guth from people like me. <grin> Linde pointed out that both he
and Prof. Guth theorized that the decay of the false vacuum did not
happen all at once either. They both believe that while some regions
decay into universes, other regions keep expanding and creating other
universes. And if that weren't enough, they also believe that
"residual" false vacuum from the creation of all these universes creates
still more of 'em. As noted by Linde - and I was writing this down as
fast as I could, so I hope I have it right - he described this as "the
eternally existing self-reproducing inflationary universe." Pretty
cool, huh!
Anyway, a great time had by all.
(If you missed the lecture, and still want to see it, have James Turley
construct a Gott Time Machine for you ... uh, one that won't collapse on
itself. <grin>)
...Bob...
Bob Czerwinski