Universe(s) Origin(s) 4 of 7 - Universes
from Black Holes?
(Top Posts - Science - 072802)

Excerpts from "The Life of the Cosmos" (Lee Smolin,
ISBN 0-19-512664-5) ...
http://www.amazon.com/exec/obidos/ASIN/0195126645

... quantum effects might completely eradicate the singu-
larity. In this case there would be no moment of creation.

Time would instead stretch indefinitely far into the past.
Regardless of inflation, there would have been enough
time for all the regions of the universe to come into con-
tact. This would not mean that cosmological inflation is
wrong, for there are other reasons one might want to
consider it. But in this case we have to ask what hap-
pened before the "Big Bang".

That term would no longer refer to a moment of creation,
but only to some dramatic event that led to the expansion
of our region of the universe. In this situation it becomes
possible to ask if there were processes which acted be-
fore the "Big Bang" to choose the parameters of elemen-
tary particle physics.

... if there is not enough matter to stop the expansion, it
will never collapse -- it will keep expanding forever. Pre-
sently, the evidence is that the universe as a whole will
not recontract. ... we know for a fact that there are
many small bits of it that have collapsed under the force
of their own gravitational attraction. These are the black
holes.

It is not hard to understand what a black hole is. They
are simple and necessary consequences of two facts.
First, the existence of a force like gravitation that is uni-
versal and attractive; and second, the fact that nothing
can travel faster than the speed of light.

... A black hole is simply anything that has shrunk to a
small enough size that the velocity you need to escape
from it is larger than the speed of light. In this situation
neither light, nor anything else, can escape.

... A conservative estimate is that there is about one
black hole for every ten thousand stars. This means
each galaxy contains at least one hundred million black
holes.

What lies beyond the horizons of all of these black holes?

The story here is very much like the story of the Big Bang,
only in reverse. If we assume that Einstein's general theory
of relativity gives a correct description of what happens
to a collapsing star, then it is quite certain that what lies
inside of each black hole is a singularity.

... There is an important difference from the case of the
cosmological singularity, which is that in a black hole the
singularity lies in the future rather than in the past. Accord-
ing to general relativity every bit of the collapsed star and
every particle that falls afterwards into the black hole will
end up at a last moment of time, at which the density of
matter and strength of the gravitational field become infi-
nite.

However, do not trust general relativity to give us the
whole story about what happens inside a black hole, for
the same reason we don't trust it in the cosmological case.

As the star is squeezed towards infinite density, it must
pass a point at which it has been squeezed so small that
effects coming from quantum mechanics are at least as
important as the gravitational force squeezing the star.

Whether there is a real singularity is then a question that
only a theory of quantum gravity can answer.

... Suppose that the singularity is avoided, and time goes
on forever inside of a black hole. What then happens to
the star that collapsed to form the black hole? As it is
forever beyond the horizon, we can never see what is
going on there. But if time does not end, then there is
something there, happening. The question is, What?

This is very like the question about what happened "be-
fore the Big Bang" in the event that quantum effects allow
time to extend indefinitely into the past. There is indeed a
very appealing answer to both of these questions, which
is that each answers the other. A collapsing star forms a
black hole, within which it is compressed to a very dense
state.

The universe began in a similarly very dense state from
which it expands. Is it possible that these are one and the
same dense state? That is, is it possible that what is beyond
the horizon of the black hole is the beginning of another
universe?

This could happen if the collapsing star exploded once it
reached a very dense state, but after the black hole horizon
had formed around it. If we look from outside of the hori-
zon of the black hole we will never see the explosion, for
it lies beyond the range of what we can see.

The outside of the black hole is the same, whether or not
such an explosion happens inside of it. But suppose we
do go inside, and somehow survive the compression down
to extremely high density.

At a certain point there is an explosion, which has the effect
of reversing the collapse of matter from the star, leading to
an expansion. If we survived this also, we would seem to
be in a region of the universe in which everything was mov-
ing away from each other. It would indeed resemble the
early stages of our expanding universe.

This expanding region may then develop much like our own
universe. It may first go through a period of inflation and
become very big. If conditions develop suitably, galaxies
and stars may form, so that in time this new "universe" may
become a copy of our world.

Long after this, intelligent beings may evolve who, looking
back, might be tempted to believe that they lived in a universe
that was born in an infinitely dense singularity, before which
there was no time. But in reality they would be living in a new
region of space and time created by an explosion following
the collapse of a star to a black hole in our part of the uni-
verse.

... if we accept the hypothesis that quantum effects eliminate
the singularity at the beginning of the universe, and eliminate
as well the singularities inside of black holes, we have the
possibility that what lies beyond the boundaries is much
vaster than our own visible universe.

... if time does not end at black hole singularities it must con-
tinue, perhaps forever, in regions inaccessible to us. And
then there must be many such regions because there seems
to be no way to avoid the estimate that a large number of
stars must end their lives as black holes.

Perhaps it makes it a little easier to contemplate this possi-
bility if one recalls that by itself the simple proposal that
time never ends forces us already to conceive of an infini-
tude of events taking place that we, in our finite lifetimes,
can never know of. All this picture really does is to rear-
range all of these inaccessible moments.

There is no longer a simple linear progression. Instead time
branches like a tree so that each black hole is a bud that
leads to a new universe of moments.

(end excerpts)

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---
What Is the Future of Cosmology
by Lee Smolin
http://www.pbs.org/wnet/hawking/mysteries/html/bioUnssmolin-1.html
---

Excerpts:

Where are fundamental physics and cosmology going?

... The most important principle of 20th-century physics
is that all observable properties of things are about relation-
ships. Even space and time must be spoken about in terms
of relationships. There is no such thing as space indepen-
dent of that which exists in it and no such thing as time
apart from change.

... since Darwin, we know that structure and complexity
can be self-organized. We understand that there are natural
processes, easily comprehensible, by which organization
can arise naturally and spontaneously, without any need
for a maker outside of the system.

This requires, however, that we take a more historical
view of fundamental physics and cosmology. We must
be open to the possibility that the answers to many of
the questions we have about why the elementary particles
or the fundamental forces are as they are-and not other-
wise-may have answers that are, at least in part, historical.

... string theory seems itself to point to the need to include
an historical aspect in fundamental physics. If we want to
know all the answers to our questions about electrons and
protons, we are going to have to understand why the uni-
verse we see around us emerged from the Big Bang with
one set of laws rather than another.

... I have proposed one possible answer: something like
natural selection acts on the choice of the laws of physics.

The basic idea is that black holes give rise to new regions
of space and time, and that at these events, which resemble
our Big Bang, the laws of physics can change.

When worked out in detail, this idea leads to a scientific
theory which makes predictions which are testable.

The basic prediction is that no small change in the masses
of the elementary particles or the strengths of the forces
would lead to a world with more black holes than ours. So
far, although a number of astronomers have tried to find
counterexamples, this prediction has held up.

... What for me is most provocative is the possibility that,
for this to work, we will have to extend the Darwinian idea
that the structure of a system must be formed from within
by natural processes of self-organization-to the properties
of space and time themselves.

In fact, there are other reasons to expect that space and time
should be self-organized. Systems which are self-organized
turn out to be complex systems.

... Of course, this does not mean that these ideas are right;
only observation and experiment can, in the end, tell us that.

... We enter the 21st century with new ideas and wide hori-
zons, with much to do and everything to talk about.

(end excerpts)

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Posts in this series:

Universe(s) Origin(s) Preface
http://prohuman.net/universes_origins_preface.htm

Universe(s) Origin(s) - 1 of 7
}}} String Theory / Infinities / Singularities {{{
http://prohuman.net/universes_origins_1_of_7.htm

Universe(s) Origin(s) - 2 of 7
}}} No Origin of the Universe? {{{
http://prohuman.net/universes_origins_2_of_7.htm

Universe(s) Origin(s) - 3 of 7
}}} Multiverse? {{{
http://prohuman.net/universes_origins_3_of_7.htm

Universe(s) Origin(s) - 4 of 7
}}} Universes from Black Holes? {{{
http://prohuman.net/universes_origins_4_of_7.htm

Universe(s) Origin(s) - 5 of 7
}}} Cyclic Universe? {{{
http://prohuman.net/universes_origins_5_of_7.htm

Universe(s) Origin(s) - 6 of 7
}}} Einstein / Big Bang / Superstrings {{{
http://prohuman.net/universes_origins_6_of_7.htm

Universe(s) Origin(s) - 7 of 7
}}} Nothing / Everything {{{

http://prohuman.net/universes_origins_7_of_7.htm

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