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starship-design: Other Universes I



I  just know I am going to regret forwarding this one, but, it was getting 
kind
of slow...

________________________________________________________________________  
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Other Universes I


by John G. Cramer

Alternate View Column AV-02
Keywords: cosmology, bubble, universe, inflation
Published in the September-1984 issue of Analog Science Fiction & Fact 
Magazine;
This column was written and submitted 2/10/84 and is copyrighted 1984, 
John G. Cramer. All rights reserved.
No part may be reproduced in any form without the explicit permission of 
the author.


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In the fullness of Creation do other universes, other Worlds, exist? Are 
there Worlds where history is different? Where triumphant Nazis rule an 
aryan-ized planet? Where Napoleon defeated Wellington and went on to 
conquer England? Where the Persians beat the Greeks at Marathon, and 
Western Civilization never happened? Where Homo-Sap never made it, and 
dinosaur decendants, un-extinguished and evolved over 65 million years, are 
the dominant life form?

Are there Worlds where the laws of physics are not quite the same? Where 
light travels faster? Where gravity is stronger? Where the nuclear binding 
force is weaker? Where electrons have a smaller charge? Where the 
Uncertainty Principle is less uncertain?

Are there Worlds which are radically different from ours? Where there are 
no chemical elements except hydrogen and helium? Where stars never formed? 
Where every atom has a nucleus of anti-protons and anti-neutrons orbited by 
positrons? Where time runs backwards? Where the Big Bang never Banged at 
all, and space is still crunched up into a single geometrical point? Where 
the strong, weak, electromagnetic, and gravitational forces are all the 
same force?

These are intrinsically fascinating questions. And a few of them have 
provided backdrops for some of the best science fiction written. In this 
Alternate View column I want to examine an area of contemporary physics, 
the "new inflationary scenario" of cosmology, which has something to tell 
us about these questions. And in my next (October) Alternate View column, 
we will look at the same questions using the "Other Worlds" interpretation 
of quantum mechanics, a very different area of physics which also has much 
to say about alternate universes.

GUTs cosmology is a recent development which has come from a joining of the 
ideas of Big Bang cosmology (the way the universe evolved from the initial 
Big Bang) with GUTS or Grand Unification Theories (see The Alternate View, 
Analog, July, 1984). In the 1950's, George Gamow and his students developed 
the Big Bang model for describing the initial stages and evolution of our 
universe. The theory was neglected (and even ridiculed) by the physics 
"mainstream" until 1965, when Penzias and Wilson announced the detection of 
cosmic 2.7deg. K microwave radiation produced in an early phase of the Big 
Bang. Suddenly, the Big Bang model was an experimentally verified fact. It 
became the "standard" cosmological model and revolutionized astrophysics. 
But soon physicists began to realize that it did not explain everything 
about the evolution of the universe. It became obvious that there were 
problems built into the description.

These problems have become known as:

(1) The Problem of Matter: Why is there more matter than antimatter in the 
universe?

(2) The Problem of Uniformity: Why is the universe so homogeneous, when its 
parts went out of speed-of-light contact very early in the Big Bang and are 
only "recently" rejoined?

(3) The Problem of Flatness: Why does the universe have just the right 
density of matter in its volume to be precisely on the borderline between 
re-collapse and continuous expansion?

(4) The Problem of Monopoles: Why aren't there more magnetic monopoles 
around, when the standard model predicts that there should be an enormous 
number of them?

A few decades ago these would all have been considered metaphysical 
questions, not proper subjects for physical investigations. But 
contemporary physicists, emboldened by the recent successes in particle 
physics, have found ways of approaching them. And they have made impressive 
progress toward answering them through some new ideas arising from the 
Grand Unification Theories mentioned above.

The Big Bang + GUTs scenario goes something like this: there are two kinds 
of space, which we might call H-space and N-space. Here N stands for 
"normal" and H refers to Higgs, the Scottish physicist who first suggested 
the possibility that H-space, also called "the false vacuum" might exist. 
We live in N-space. We have never experienced H-space directly, but recent 
work in particle physics suggests that N-space could be converted to 
H-space by pumping enough energy into a small enough region. And perhaps 
there is also a tiny region of H-space at the core of each magnetic 
monopole, if such particles exist in our universe.

In N-space the three strongest fundamental forces of the universe (the 
strong, weak, and electromagnetic interactions) can easily be 
distinguished. They have very different strengths, and their change with 
distance is very different. But in H-space these forces are all the same 
and cannot not be distinguished from one another. In H-space quarks, 
electrons, neutrinos, and photons are all the same particles with nothing 
to distinguish them.

Immediately after the Big Bang there was so much energy in such a small 
volume that all space was H-space. During this period, the universe 
expanded far faster than its present expansion rate. But as the universe 
expanded and more volume became available for the same amount of energy, 
the energy/volume ratio of space fell. About one millionth of a second 
after the start of the Big Bang, when the universe had expanded to about 
the size of a grapefruit, the energy/volume ratio had fallen to a low 
enough value that N-space became possible and H-space became 
"supersaturated". Regions of N-space begin to "precipitate out". As such 
regions of N-space appeared, the three forces within these regions "split" 
from one another, becoming different forces rather than the same force and 
the corresponding particles (hadrons, leptons, photons) also became 
distinguishable.

This "splitting" is like the change from one state of matter to another, 
for example, boiling water changing from liquid to steam. But in this case 
it is space itself which "boiled". And, as you might expect of a boiling 
medium, "bubbles" formed. But the bubbles which form when space itself 
boils are not our ordinary bubbles with gas inside and liquid outside. 
These bubbles have N-space inside and H-space outside. Our universe just is 
one of these bubbles. We have experienced only N-space because we are stuck 
inside it. And there should be very many N-space bubbles in the H-space 
"sea".

The boiling of space, the conversion of H-space to N-space, frees a truly 
enormous amount of energy. This energy ends up in the walls of each bubble, 
causing the walls to move outward from the central region at nearly the 
speed of light. So each bubble-universe expands, as ours seems to still be 
doing some 4 billion years after the Big Bang.

This revised version of the Big Bang model is called "the New Inflationary 
Scenario". It seems to provides solutions to all of the problems mentioned 
above of the "standard" Big Bang model. There is an excess of matter over 
antimatter in our universe because a "CP violation" occurred during the 
boiling phase, producing about .00000002% more protons than antiprotons 
(and .00000002% more electrons than positrons). The vast majority of the 
matter and antimatter particles from the Big Bang paired off and 
annihilated, but this small residue remained to become the protons and 
electrons of which our world is made. Uniformity is accounted for because 
the chunk of the Big Bang forming our universe was small enough and 
expanded fast enough. Flatness comes directly from the way in which the 
bubble expands, keeping the balance of matter and expansion speed of the 
universe precisely at the balance point between infinite expansion and 
eventual recontraction. The monopole number is reduced because the 
monopoles from the Big Bang have a large number of bubble-universes in 
which to end up, not just one. There is even some reason to suspect that 
each bubble-universe contains exactly one magnetic monopole, which is the 
"nucleating agent" that caused it to "precipitate" from H-space, like the 
dust particle at the heart of every raindrop.



So there are other Worlds! In the new inflationary scenario there are a 
very very many other Worlds. But these Worlds are not easy to reach from 
here. In the first place, there is just enough mass in our universe to 
cause our local space to exactly close on itself. In effect we are barely 
trapped in a rapidly expanding black hole. And there seems no way of 
leaving our local space to enter the sea of H-space "outside". Perhaps that 
is just as well, because the surrounding H-space is probably not compatible 
with body chemistry (or with life). On inaccessible other shores of the 
H-space sea will be other Worlds, islands of N-space that came from the 
same Big Bang which produced ours. They should be similar to our World, but 
perhaps they are also different.

But in what way can these other bubble-universes be different from ours? In 
N-space the laws of physics (as we know them) should apply. How then, 
without changing the laws of physics, might these other Worlds be 
different? First, there is no particular reason why the CP violation 
mentioned above should always lead to an excess of matter over antimatter. 
So perhaps some of the other Worlds are all antimatter. Second, no one 
really understands why time in our World runs in the direction it does. So 
perhaps some of the other Worlds would have time running in the opposite 
direction. Third, when the bubbles formed, they would probably have many 
different sizes, each with a different amount of mass-energy trapped 
inside. What would that do?

A relatively untested physical idea called Mach's Principle, first proposed 
by Ernst Mach (known for the Mach Number of supersonic flight) gives us a 
way of answering this question. It asserts that the force of inertia, which 
we experience as resistance to acceleration, is the result of the 
gravitational pulls of all the other masses in the universe (the Sun, other 
stars, and even distant galaxies). If Mach's Principle can be applied to an 
individual bubble-universe, then the inertia which an object has (which we 
call its inertial mass) should depend directly on how much mass-energy is 
contained in that bubble-universe. The gravitational mass (how much pull 
due to gravity a massive object experiences) should not depend on this. The 
net result is that an object in another bubble-universe would, have a 
different ratio of gravitational to inertial mass.

This would change the masses of protons, electrons, etc. in all of the laws 
of physics in which the mass in the formula means reaction to inertia (as 
it usually does in atomic and nuclear physics). Sizes of atoms, positions 
of orbiting electron shells, chemical bonds linking one atom to another, 
nuclear structure, and synthesis in supernovae of heavier nuclei from 
lighter nuclei would all be altered.

Suppose that we could build a machine, a "Universe-swapper" by which could 
transport a Voyager safely across the H-space sea from our World to one of 
its bubble-universe siblings. What would we find? If the universe visited 
was filled with antimatter the Voyager would probably have an unpleasant 
time. All of the matter sent across would be annihilated on contact with 
with antimatter on the other side. Our Voyager would have to remain in the 
hardest vacuum to avoid a lethal dose of radiation from the random anti-gas 
molecules of deep space annihilating on contact with his vehicle or space 
suit.

To natives of the time-reversed universes, their universe would appear to 
be contracting to a Big Crunch rather than expanding from a Big Bang. The 
light from distant stars (if any) would be blue shifted rather than red 
shifted, making the sky very bright and perhaps intolerably hot. Our 
Voyager, if he retained his own time direction, would perceive the sibling 
universe as running backwards. He would watch the Second Law of 
Thermodynamics operating in reverse: water would run uphill, the dead would 
come to life, food would be produced by un-eating it so that it could be 
converted into plants and animals. Or perhaps our Voyager would be swept 
along with the time direction of the sibling universe. In that case, he 
would find on his return to our universe that he had returned before the 
time of his departure. This, as most SF readers already know, can produce 
some interesting and paradoxical situations.

But what about the Worlds containing normal matter and having time 
proceeding in the proper direction? If Mach's principle works the inertial 
masses of objects will be altered, effectively changing the laws of physics 
in these Worlds. In a broad class of such universes, no stars or galaxies 
would have formed; in another group there would be stars and galaxies, but 
no synthesis of elements heavier than helium; in another group there would 
be stars, galaxies, and the usual chemical elements, but no planets; and in 
a another group there would be planets, but none that would support life. 
In only an extremely small fraction of the universes would life be 
possible. And it is difficult to say how much variation in the laws of 
chemistry would be permitted after the physics worked out to produce 
life-supporting planets. Clearly the carbon chemical bond is a subtle 
prerequisite to life-as-we-know-it which would not tolerate much tinkering. 

So our Voyager, upon entering a sibling bubble-universe, might find that 
his body chemistry had gone bonkers, perhaps fatally. And we must also 
remember that the operation of solid-state electronics depends on the 
accidental placement of a "gap" between the atomic states of semiconductor 
materials like silicon and germanium. Our universe-swapper device and its 
recording equipment should probably be built with old-fashioned tubes 
rather than solid-state electronics in order to be "universe-tolerant" and 
behave itself after reaching its destination.



My friend Gene Wolfe has suggested that if our own universe is not all of 
Creation but only one bubble out of many in the stream of Time, then 
calling it "The Universe" is no longer sufficient. We need a Name for it. 
He suggested "Malkuth", which is the Kabbalist name for "world". But I find 
Malkuth rather unappealing; it sounds too much like "uncouth" and would 
give completely the wrong impression of our Universe to an outsider.

So, in order to correct this Name deficiency, I hereby announce the 1984 
ANALOG Name-the-Universe Competition!! The winner will receive a free one 
year subscription to this magazine and will, in addition, achieve the true 
immortality of having chosen the proper name of an important natural 
object, in this case the Universe in which we live. Send your entries (one 
per letter please) to me in care of ANALOG, 380 Lexington Avenue, New York, 
NY 10017. Include your name and address, your suggestion for the Name of 
the Universe, and a brief statement of why you feel the Name is 
appropriate. The winning Name and the name of the winner will be announced 
in a later AV column (probably in early 1985).



REFERENCES:

D. N. Schramm, Physics Today 36 #4, 27 (April, 1983).

A. H. Guth, Physical Review D 23, 347 (1981).

A. Alberecht and P. J. Steinhardt, Physical Review Letters 48, 1220 (1982).



FIGURE CAPTION:

Bubbles in the Big Bang: some "bubbles" may form antimatter universes; some 
may form universes in which time runs backwards, some may resemble our 
universe but with altered physical laws.


Lee