Excerpts from "Before the Beginning, Our Universe and
Others" (Martin Reese, ISBN 0-7382-0033-6) ...
http://www.amazon.com/exec/obidos/ASIN/0738200336
.... Colossal though they may be, stars and galaxies rank
low on the scale of complexity. That is why it isn't pre-
sumptuous to aspire to understand them. A frog poses
a more daunting scientific challenge than a star.
Planetary systems are common around other stars. Given
a propitious environment, what's then the chance of life
getting started, and of evolving to an "interesting" stage?
This biological question is still unsettled.
.... We can confidently trace cosmic history back to the
first second. The ground gets shakier when we extrapolate
still farther back, into the first millisecond.
.... The challenge facing the next Newton or Einstein is to
"unify" the forces of nature: to interpret electric, nuclear,
and gravitational forces as different manifestations of a
single primeval force.
.... As our universe cooled, its specific mix of energy and
radiation, even perhaps the number of dimensions in its
space, may have arisen as "accidentally" as the patterns
in the ice when a lake freezes. The physical laws were
themselves "laid down" in the big bang.
.... Our entire universe may be just one element -- one atom,
as it were -- in an infinite ensemble: a cosmic archipelago.
Each universe starts with its own big bang, acquires a dis-
tinctive imprint (and its individual physical laws) as it cools,
and traces out its own cosmic cycle. The big bang that trig-
gered our entire universe is, in this grander perspective, an
infinitesimal part of an elaborate structure that extends far
beyond the range of any telescopes.
---
-insert-
Sir Martin Rees, Astronomer Royal and Royal
Society Research Professor at Cambridge University
http://www.petergruberfoundation.org/rees.htm
Excerpt: ... renowned for his extraordinary intuition in
unraveling the complexities of the universe. He has been
a leader in the quest to understand the physical processes
near black holes and is responsible for major advances in
our understanding of the cosmic background radiation,
quasars, gamma-ray bursts, and galaxy formation. He has
contributed to almost every area of cosmology and astro-
physics and has been an inspiring leader, eloquent spokes-
person, and patient guide for astronomers all over the
world. ...
-end insert-
---
Some cosmologists speculate that new "embryo" universes
can form within existing ones. Implosion to a colossal den-
sity (around, for instance, a small black hole) could trigger
the expansion of a new spatial domain inaccessible to us.
Universes could even be "manufactured" -- the experimen-
tal challenge is far beyond present human resources, but
may become feasible, especially if we recall that our uni-
verse has most of its course still to run. No information
could be exchanged with a daughter universe, but it could
bear imprint of its parentage.
Our own universe might be the (planned or unplanned)
outcome of such an event in some preceding cosmos.
The traditional theological "argument from design" then
reasserts itself in novel guise.
Most naturally created universes would be stillborn in the
sense that they could not offer an environment propitious
for complex evolution: they would have too short a time
span, the wrong number of dimensions, allow no chem-
istry, or be otherwise maladjusted. But our universe may
not be the most complex: others in the ensemble may
have richer structure, beyond anything we can imagine.
.... Should We Believe In a Hot Big Bang?
.... There is firm empirical support (and a firm link with
known physics) for inferences going back to when our
universe was just a few seconds old -- the implications
from the microwave background, and from cosmic hel-
ium.
.... when ... we venture all the way back into the first mil-
lisecond, we are on shakier ground, and shouldn't disguise
this.
Cosmologists shouldn't conflate things that are quite well
established with those that are not yet in that state.
.... But some questions that were once entirely speculative
are now coming into serious scientific focus.
.... You may be thinking: Isn't it absurdly presumptuous
to claim that we can ever know anything about the begin-
nings of our entire universe? Not necessarily. It is com-
plexity, and not sheer size, that makes a system hard to
understand.
The sun is easier to understand than the earth ... in the
even more extreme environment of the primordial fireball,
everything must surely have been reduced to its most
basic components. The early universe could be easier to
understand than the smallest living organism. It's biolo-
gists and the Darwinians who face the toughest challenge.
.... Dark matter dominates galaxies. How galaxies form,
what they look like, and the way they cluster depend on
how the dark matter behaved as our universe expanded.
.... Ordinary atoms may comprise less than 10 percent
of the universe, in terms of mass; cosmic dynamics
would be only slightly changed if they weren't there at
all. But atoms are plainly a prerequisite for our existence.
.... Cosmology used to be derided as a science in which
facts were so scarce that theory was unconstrained. That
is certainly the case no longer: indeed, rather than there
being a lack of facts, it is already a challenge to recon-
cile all the data with any single scheme.
.... The Russian cosmologist Andrei Linde advocates
chaotic inflation -- a more complex scenario where the
entire universe (the "multiverse" in the terminology I'm
using) could be infinite and eternal, but continually gener-
ates inflating regions which evolve into separate universes.
What we call our universe may be one domain of an
eternally reproducing cycle of different universes. These
are now disconnected from ours, but can be traced back
to common ancestors. The big bang that led to our uni-
verse is just one event in a grander structure.
.... Separate universes, or separate domains within an infi-
nite universe, might have cooled down differently, even
ending up governed by different laws.
.... Light that reaches us in the far future, from regions far
beyond our present horizon, may reveal that we occupy
a (perhaps atypical) patch embedded in a grander structure.
We could even, for instance, inhabit a finite or "island"
universe, whose edge may sometime come into view.
Even a universe that collapses, after tracing out a vast cos-
mic cycle, need in no sense be the whole of reality: in the
grander perspective of the multiverse, it is just one "epi-
sode", or one domain.
An "eternally inflating" multiverse may sprout separate do-
mains; the laws of physics may vary between one universe
and the next. Moreover, inside every black hole that col-
lapses may lie the seeds of a new expanding universe.
This ensemble, the multiverse, could encompass universes
governed by different laws and fundamental forces, and
containing different kinds of particle. Universes would not
live equally long, nor have equally eventful histories: some,
like ours, may expand more than 10 billion years; others
may be stillborn because they recollapse after a brief exis-
tence, or because the physical laws governing them aren't
rich enough to permit complex consequences.
.... Only some universes (our own, of course, among them)
would end up as propitious locations for complexity and
evolution.
---
-insert-
Interview of Sir Martin Rees regarding his book,
"Our Cosmic Habitat"
http://www.space.com/spacelibrary/books/library_rees_020104.html
Excerpt: ... Can you define what you mean by different
universes? What are the possible types that have been
conceived?
Several theorists have speculated on different lines.
There's the concept of 'eternal inflation' due to Linde
and others, in which big bangs recur repeatedly in an
ever-expanding substratum. Some theorists have con-
jectured that new 'big bangs' could sprout inside black
holes.
And there is the idea that there could be a 4th spatial
dimension, so that other universes could exist just a few
millimeters away from us in a dimension we can't pene-
trate (since we are 'imprisoned' in three spatial dimen-
sions).
There is also the rather different idea of 'parallel worlds'
which some people believe offers the best interpretation
of quantum mechanics. Even if other universes existed,
we would still need to ask whether they are replicas of
ours, or if different laws could govern them. ...
-end insert-
---
.... Time In Other Universes
.... Near the beginning ... of the universe, everything would
be squeezed into an exotic state that mixes up the dimen-
sions of "space" and "time". ... On this tiny scale, some
theories, going back to Wheeler's pioneering ideas in the
1950s, suggest that the time dimension was intermingled
with the three spatial dimensions [left/right, forward/back-
ward, up/down] into a froth of "space-time foam."
According to currently popular superstring theories, there
may be six extra dimensions. Space is tightly "rolled up"
in these extra dimensions, so they manifest themselves
only on very tiny scales. Hartle and Hawking have devel-
oped a different approach to "quantum cosmology" and
the beginning of time. They suggest that the distinction
between time and space was initially blurred.
.... Our concepts of space and time derive from experience
and perceptions in the everyday world. We shouldn't be
surprised that our intuition fails on either the cosmic or the
submicroscopic scale.
.... Some new insight may eventually reveal that space-time
with 3 + 1 dimensions, like ours, is the only possible one.
But there currently seems nothing absurd about a universe
with extra dimensions.
According to superstring theories, the ultraearly universe
had 10 dimensions. The extra six would have rolled up and
"compactified", rather than expanding along with the others.
Theorists can't yet tell us whether this compactification
inevitably leads to our 3 + 1 dimensions.
(Whether a universe could have more than one time-dimen-
sion is less straightforward. Certainly a language with more
tenses would be needed to describe what happens in it!)
.... There may be other universes -- uncountably many of
them -- of which ours is just one. In others, the laws and
constants are different.
.... Another approach to quantum mechanics is the "many-
worlds" theory, proposed by Hugh Everett in the 1950s.
.... The "many-worlds" approach envisages our entire uni-
verse as a single quantum system. ... A newer variant due
to David Deutsch replaces the idea of branching universes
by an infinite ensemble of universes, evolving in parallel
and displaying greater variety as time goes on.
.... Smolin's Speculation
Natural selection of "favored universes seems the stuff of
science fiction. However the American cosmologist Lee
Smolin conjectures that the multiverse could display the
effects of heredity and selection. When a black hole col-
lapses, he speculates that another universe sprouts from
its interior, creating a new expanse of space and time dis-
joint from our own.
Small universes, in which there was too little space or
time to form many black holes, would not leave many
progeny. Nor, he argues, would even a large universe if
its physics prohibited stars from ever terminating as black
holes.
.... Since the number of progeny a universe has depends
on the laws prevailing within it, there is a selection pres-
sure. Many generations, or many iterations, would lead
to a "takeover" by the universes that generate the most
numerous progeny. These would be the ones governed
by laws that allowed the largest number of black holes
to form. ...
(end excerpts)
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(continued in 3b of 7)
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Posts in this series:
Universe(s) Origin(s) Preface
http://www.ghg.net/phf/universes_origins_preface.htm
Universe(s) Origin(s) - 1 of 7
}}} String Theory / Infinities / Singularities {{{
http://www.ghg.net/phf/universes_origins_1_of_7.htm
Universe(s) Origin(s) - 2 of 7
}}} No Origin of the Universe? {{{
http://www.ghg.net/phf/universes_origins_2_of_7.htm
Universe(s) Origin(s) - 3 of 7
}}} Multiverse? {{{
http://www.ghg.net/phf/universes_origins_3_of_7.htm
Universe(s) Origin(s) - 4 of 7
}}} Universes from Black Holes? {{{
http://www.ghg.net/phf/universes_origins_4_of_7.htm
Universe(s) Origin(s) - 5 of 7
}}} Cyclic Universe? {{{
http://www.ghg.net/phf/universes_origins_5_of_7.htm
Universe(s) Origin(s) - 6 of 7
}}} Einstein / Big Bang / Superstrings {{{
http://www.ghg.net/phf/universes_origins_6_of_7.htm
Universe(s) Origin(s) - 7 of 7
}}} Nothing / Everything {{{
http://www.ghg.net/phf/universes_origins_7_of_7.htm
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~~~
Pro-Humanist FREELOVER
http://www.ghg.net/phf
(Freethinking Realist Exploring
Expressive Liberty, Openness,
Verity, Enlightenment, & Rationality)
~~~
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