Friar Bellows

If he's genuinely curious, send him over to:

<a href="http://www.astro.ucla.edu/~wright/cosmo_01.htm" target="_blank">Ned Wright's Cosmology Tutorial</a>

I wouldn't recommend Stephen Hawking's book. He's a great physicist, but not a great popularist. I recommend Edward R. Harrison's:

<a href="http://www.amazon.com/exec/obidos/ASIN/052166148X/qid=1016532460/sr=1-7/ref=sr_1_7/104-2590335-5653546" target="_blank">Cosmology: The Science of the Universe</a>

A bloody brilliant book if I may say so.

[ March 19, 2002: Message edited by: Friar Bellows ]</p>

Sojourner553

It seems to me there are some of you out here that need to brush up on the latest science, before putting out some of your statements:


The Big Bang

During the early 1900's, when astronomy was still in its infancy, scientists
favored a model of the universe that was eternal or static. When Albert
Einstein's equations on general relativity predicted an expanding universe in
1916, Einstein "fudged" his equations, entering a constant to force the
equations back to a static universe. Years later, after Hubble's measurements
showed the universe was indeed expanding (initially Hubble was trying to prove
the universe was static), scientists began switching over to the Big Bang theory
of the universe. Einstein later referred to the tampering with his relativity
equations as "the greatest blunder of my life."

Further scientific discoveries, such as the discovery of a constant microwave
background in the universe, further entrenched the Big Bang as the favorite
model among scientists to explain the origin of the universe. Theists were
generally delighted at the parallels between the Big Bang theory and the Genesis
description of how God ordered the universe into existence with his fiat, "Let
there be light." (Creationist Christians were an exception: for the Big Bang
theory also held that the universe developed over billions of years, instead of
being created in the biblical six days.)

Non-theists (such as Carl Sagan) speculated our universe might be undergoing
an infinite series of Big Bang expansions, followed again by contractions. This
was a testable hypothesis, however, because this meant that the universe's
expansion should be decelerating or slowing down. Measurements were taken in
1998, with results that dramatically surprised everyone! For not only was there
NO deceleration-but instead the expansion of the universe was very much
accelerating (speeding up scientists would theorize, under the influence of a
mysterious "dark energy", an antigravity embedded within space itself.) At this
measured fast rate of expansion, scientists began to theorize that galaxies and
solar systems would fly further apart, so that billions of years from now, there
would be less and less starlight until earth's night skies eventually turn
completely dark. (Star Trek wannabes were not happy with the news that space
travel just got more difficult for the distant future.)

Big Bang Creation Theories

With the oscillating universe model discredited, some theists tried to use
the Big Bang model to "prove" the existence of God. One proof (called the kaläm
cosmological argument) uses the following logic: (1) Whatever begins has a
cause; (2) The universe began to exist; (3) Therefore, the universe has a cause.
The fallacy with this argument is with premise (1) "Whatever begins has a cause"
is only an assumption that theists "believe" is true-especially since "cause"
can be understood to mean natural (as opposed to supernatural) cause. Also
premise (2) "the universe began to exist" is an assumption, because we do not
know for sure if our universe had a previous existence, or whether the Big Bang
creation is just one event within one or more larger processes.

A second popular theist proof revolving around the Big Bang goes like this:
(1) Time began when the Big Bang created the universe; (2) God, as creator of
time, is outside of time; (3) For there to be a beginning, time must exist; (4)
Therefore, God has always existed and does not require a cause, even though he
created the earth. Here, premise (2) that "God is outside of time" is an obvious
assumption inserted to make the end result work. One could just as easily assume
God is "inside" of time. Premise (1) that "time began with the Big Bang" is
also an assumption, which modern physicists debate: Examples include Stephen
Hawkings' (who argues there was no precise moment when time began) and Julian
Barbour (who claims that time "is simply an illusion created by our brains.")

Stephen Hawkings, in his bestseller book, "A Brief History of Time,"
proposed a cosmological model that infers the Big Bang does NOT require a
creator. His proof goes as follows: (1) there was no precise moment when time
began; (2)Therefore there was no precise moment when the universe began.
(3)This implies there would be no need nor role for a creator. (Hawkings' proof
does not have the logical fallacies of the other proofs above, because it does
not state that a Creator or God is impossible. Although Stephen Hawkings
generally speaks of "God" elsewhere in his writings, his meaning is more as "an
abstract principle of order and harmony" rather than a personal deity.)

In conclusion, the Big Bang model can neither prove nor disprove a God as
its "cause". Theories for God based on the Big Bang are really variations of
the Argument from Design, which was disproved by Kant and others (see the
discussion below under Argument from Utility.) Many theists have dropped the Big
Bang "proof" and moved on to more powerful arguments that could infer the
existence of a creator.

...
Infinite Inflating Universes

Alan Guth's inflationary model of the universe – which is currently
considered the best model for explaining the universe by physicists-- holds that
our universe is not unique, but arose from a quantum fluctuation in space.
Guth's theory is complex but following is a layman's explanation taken from
DISOVER Magazine:

Quantum theory holds that a vacuum, like atoms, is subject to uncertainties.
This means that, there is an infinitesimally low probability that pairs of
subatomic particles – usually one positive and one negative – can pop into
existence, lasting a split second (on the magnitude of .000000000000000000001
second) in what physicists call a vacuum fluctuation. In 1980, Guth put forth
an inflationary model that described how a "false vacuum" (ie a peculiar form of matter predicted to exist by many particle physicists) erupted to form our
universe:

…[I]ts expansion accelerat[ed] exponentially as its repulsive force
compounded,[creating] vast quantities of ever-doubling energy, which
decayed into a seething plasma of particles such as electrons, positrons,
and neutrinos. As the early universe went along doubling every
microsecond, the stuff in it doubled too – out of nowhere. The electrons,
positrons, and neutrinos became a sort of hot soup, which 300,000 years
later neutralized to form simple atoms. The simple atoms, like hydrogen,
helium, and lithium, were ripped apart and crushed together to form more
complex, heavier atoms inside stars. Exploded into space by supernovas,
they became the matter we see—and are—today." (Brad Lemley, "Guth's Grand
Guess", DISCOVER, April 2002, p 36)

Andrei Linde of Stanford has used advanced quantum physics based on Guth's
inflationary model to take this one step further. Linde has used (what he calls
the "eternally existing, self-reproducing inflationary universe"), to describe
an infinite series of universes created before and after our universe. Brad Lemley of DISCOVER magazine described Linde's model as follows:

The multiverse... is like a growing fractal, sprouting inflationary domains
that sprout more inflationary domains, with each domain spreading and
cooling into a new universe. If Linde is correct, our universe is just
one of the sprouts.

The theory neatly straddles two ancient ideas about the origin of our
universe: that it had a definite beginning, and that it has existed
forever. In Linde's view, each particular part of the multiverse,
including our part, began from a singularity somewhere in the past,
but that singularity was just one of an endless series that was spawned
before it and will continue after it. (Brad Lemley, "MULTIPLE Universes -
Is ours the only ONE with life?" DISCOVER MAGAZINE, November 2001)

Alan Guth agrees that Linde's model is not only possible, it seems like a
sure thing. Guth wrote in his 1997 book, THE INFLATIONARY UNIVERSE, how "any
cosmological theory that does not lead to the eternal reproduction of universes
will be considered as unimaginable as a species of bacteria that cannot
reproduce." (Lemley, IBID, p 38. Note: I did not quote the first sentence above as it comes from Lemley not Guth.)

The multi-universe idea is not a new concept: In the late 1700's, the
philosopher David Hume mused that other universes might have been "botched and
bungled, through eternity, ere this system." The same idea applies: that only a
tiny fraction of universes, including ours, happens to be set at the values
required for life

Martin Rees, Britain's Astronomer Royal and author of the book JUST SIX
NUMBERS (see footnote (2) below) is a proponent of Linde's model for a multi-
universe. Rees argues that if our universe was built by a divine creator,
rather than through randomness, we should see more elegance (or less "ugliness
and complexity") in other physics constants. For example, per Rees, a divine
intelligence would probably have chosen a perfect circle for Earth's orbit, as
opposed to its actual elliptical shape. Another example given by Rees is that
the antigravity constant is just a smidgen above zero.

Of course, assuming Linde's model holds up (Rees speculates there might be
ways of testing this theory within this century) then this means the universe is
about a zillion times larger, not to mention "weirder" than almost anyone had
ever conceived of.




(small excerpt -- else I would have just posted the entire link -- taken from
<a href="http://mac-2001.com/philo/crit/PHILOSOP.TXT" target="_blank">http://mac-2001.com/philo/crit/PHILOSOP.TXT</a>

Sojourner

[ March 25, 2002: Message edited by: Sojourner553 ]</p>

Jayhawker Soule

Thanks. Unfortunately, I could not seem to get the links to work, so why not just tell us what you deduce from those sources?

Francois Tremblay

Here is another simple explanation I found recently that might appeal to your interlocutor (since it purports to be a revised version of Genesis).

<a href="http://www.extropy.org/ideas/journal/current/02-04.html" target="_blank">http://www.extropy.org/ideas/journal/current/02-04.html</a>

Skydiving_Grandma

I have been aquainted with this theory! Supposedly the guy who theorized it (I cannot recall his name) ended up killing himself because he believed he was living his life over and over again due to his new concept. I doubt that is the case, IF the universe were in a loop. But I think the theory makes SOME sense. I don't see how gravity could compact matter into something the size of an atom (pardon my small human mind). But there is no drag on these celestial bodies except for the pulls caused by gravity. So I suppose I still wonder whether we'll keep going and going or if time will "reverse" itself. Humans will know at some point.

Friar Bellows

"Fudging" is too strong a word in my opinion. Recall that the general theory of relativity argues that matter causes space to curve, and space dictates the movement of matter. When Einstein derived his "field" equation (the most important equation in general relativity) he was originally led to:

G = kT

where G is a "tensor" measuring the curvature of space, and T is a tensor measuring the distribution of matter and pressure, or in other words, the source of the gravitational field. And k is just some constant.

Einstein felt that any additional terms on the left hand side detracted from the aesthetics of the equation (e.g. no longer would G be a strict measure of curvature) and any additional terms on the right hand side were not justified by the evidence. But then he realised the cosmological implications of his version of the field equation. So, given the cosmological data of the day, he felt compelled to generalise his equations by adding a constant term to the left hand side:

G + Lg = kT

L is the cosmological constant, and g is the metric tensor, which defines "lengths" in curved space. But 13 years later, the expansion of space was discovered. Einstein would later lament that the introduction of the cosmological constant was the "greatest blunder of his life". After all, without it, he would have predicted the expansion of space.

But then again, the addition of a cosmological constant does not rule out cosmological expansion. The cosmological constant would have to take on a very specific and precise value to produce a static universe. This should immediately have been a hint to Einstein that it was far more likely that space was not static at all. He could still then have kept the term, but left it for the astronomers to measure. That way, he could have had his cake and eaten it too (i.e. whether they found a static or an expanding universe, he could have claimed credit for predicting either case).

Today, motivated by theory, physicists like to add a term to the right hand side instead of the left hand side:

G = k(T + Tv)

where Tv is the vacuum stress-energy tensor. That way, G retains its original meaning, as a strict measure of curvature, but now there is an energy density (encapsulated by Tv) associated with vacuum fluctuations (see string theory).

In summary, the addition of an extra term, whether to the right hand side or the left hand side of the field equation is not really "fudging", unless you believe the whole plausability argument leading to the field equation is an exercise in "fudging".

Sojourner553

Thanks for the science lesson, Friar Bellows:

Surely you realize though that the "fudging" term comes from historical sources, not me.

Einstein himself referred to this episode where he tampered with his more pure relativity equations as "the greatest blunder of my life."

Actually this seems pretty petty!

I thought I had much deeper issues in this article than the perfect word historians use to refer to Einstein's "blunder".

Friar Bellows

No lesson intended, I assure you. Just making a point.

Yes. Sorry to give any other impression.

It depends on exactly what he thought of as a "blunder". Adding the cosmological constant term, or failing to let the astronomers decide on its value.

Depends on your perspective.

You don't own the thread. The thread has a life of its own.

eowynn

I wonder, though, if humans would ever know. To me, it would seem that, if the universe was "repeating" itself, as was theorized, how would we know? If time started over again, with the Big Bang (and I am not saying it does; just a thought), we never would really know.

Friar Bellows

The scientific content of what I wrote above is correct, but I have seriously simplified and significantly mispresented the true historical situation. History is always more complicated than what you read in the second-hand and third-hand accounts. The lesson (for me and anyone else reading) is to go to the primary sources whenever possible. Mea culpa.