The Big Bang theory says that the entire universe was created in a tremendous
explosion about 15 billion years ago. The enormity of this event is hard to
grasp and it seems natural to ask ourselves 'What was it like then?' and 'What
happened before the Big Bang?'. To try to answer these queries, lets take a
brief journey backwards in time.

By 700.000 years, the universe is awash with the fireball radiation that keeps
all matter at a temperature of 4.000 degrees. Because of this, darkness is
completely absent since every point in the sky glows with the brilliance of the
sun. No stars, planets or even dust grains exist, just a hot dense plasma of
electrons, protons and helium nuclei. By 3 minutes, we see helium form from the
fusion of hydrogen atoms while the universe seeths at a temperature of nearly
1 billion degrees. The average density of matter is that of lead. By 1 second,
the Lepton Era ends and the ratio of neutrons to protons has become fixed at 1
neutron for every 5 protons. The temperature is now 5 billion degrees
everywhere. At about .0001 second, we watch as the Quark Era ends and the
temperature of the fireball radiation rises to an incredable 1 trillion
degrees. Quarks, for the first time, can combine in groups of two and three to
become neutrons, protons and other types of heavy particles. The universe is
now packed with matter as densly as the nucleus of an atom. A mountain like Mt.
Everest could be squeezed into a volume no greater than the size of a golf
ball!

By 1 billionth of a second, the temperature is 1 thousand trillion degrees and
we see the electromagnetic and weak forces merge into one force. The density
of the universe has increased to the point where the entire earth could be
contained in a thimble. Quarks and anti-quarks are no longer confined inside
of particles like neutrons and protons but are now part of a superheated plasma
of unbound particles. As the remaining history of the universe unfolds, a long
period seems to pass when nothing really new happens. Then, at a time 10(-35)
second after the Big Bang, a spectac ular change in the size of the universe
occurs. This is the GUT Era when the strong nuclear force becomes
distinguishable from the weak and electromagnetic forces. The temperature is an
incredable 10 thousand trillion trillion degrees and the density of matter has
sored to nearly 10(75) gm/cm3. This number is so enormous that even our
analogies are almost beyond comprehension. At these densities, the entire Milky
Way galaxy could easily be stuffed into a volume no larger than a single
hydrogen atom! Electrons and quarks together with their anti-particles, were
the major constituents of matter and very massive particles called Leptoquark
Bosons caused the quarks to decay into electrons and vice versa. If we now move
forward in time we would witness the vacuum of space undergoing a 'phase
transition' from a higher energy state to a lower energy state. This is
analogous to a ball rolling down the side of a mountain and coming to rest in
the lowest valley. As the universe 'rolls down hill' it begins a brief but
stupendous period of expansion. The universe swells to billions of times its
former size in almost no time at all.

In addition to this, a slight excess of matter over anti-matter appears becaus
of the decay of massive particles called X Higgs Bosons. As we continue to
watch the universe age, the remaining pairs of particles and anti-particles
find themselves and vanish in a tremendous burst of annihilation. From this
paroxysm, the bulk of the fireball radiation that we now observe is born.

The GUT Era is the last stop in our fanciful journey through time. If we had
asked what it was like before the GUT Era, we would immediately have entered a
vast no mans land where few indisputable facts would serve to gui de us. What
does seem clear is that gravity is destined to grow in importance, eventually
becoming the dominant force acting between parti cles, even at the microscopic
level.

G R A V I T Y

According to theories developed since the 1930's, what we call a 'force' is
actually a collective phenomenon caused by the exchange of innumerable,
force-carrying particles called gauge bosons. The electromagnetic force, which
causes like charges to attract and dissimilar ones to repel, is transmitted by
gauge bosons called photons, the strong force that binds nucleii together is
transmitted by gluons and the weak force which causes particles to decay is
transmitted by the, recently discovered, W and Z Intermediate Vector Bosons. In
an analogous way, physicists believe that gravity is transmitted by particles
called Gravitons. If gravity really does have such a quantum property, its
effects should appear once quarks and electrons can be forced to within 10(-33)
centimeter of one another, a distance called the Planck length. To acheive
these conditions, quarks and electrons will have to be collided at energies of
10(19) GeV. An accelerator patterned after the 2-mile, Stanford Linear
Accelerator would have to be 1 light-year in length to push particles to these
incredable energies! Fortunatly, what humans find impossible to do, Nature with
its infinite resources finds less difficult. Before the universe was 10(-43)
second old, matter routinely experienced collisions at these energies. This
period is what we call the Planck Era.

THROUGH A LOOKING GLASS, DARKLEY

Since our technology will not allow us to physically reproduce the conditions
during these ancient times, we must use our mathematical theories of how matter
behaves to mentally explore what the universe was like then. We know that the
appearence of the universe before 10(-43) second can only be adequatly
described by modifying the Big Bang theory because this theory is, in turn,
based on the General Theory of Relativity. General Relativity tells us how
gravity operates on the macroscopic scale of planets, stars and galaxies. At
the Planck scale, we need to extend General Relativity so that it includes not
only the macroscopic properties of gravity but also is microscopic
characteristics as well. The theory of 'Quantum Gravity' is still far from
completion but physicists tend to agree that, at the very least, Quantum
Gravity must combine the conceptual elements of the two great theories of
modern physics: General Relativity and Quantum Mechanics.

In the language of General Relativity, gravity is a consequence of the
deformati on of space caused by the presence of matter and energy. Gravity is
just another name for the amount of curvature in the geometry of 3-dimensional
space. In Quantum Gravity theory, gravity is produced by massless gravitons so
that gravitons now represent individual packages of curved space that travel
through space at the speed of light.

The appearence and dissappearence of innumerable gravitons gives the geometry
of space a very lumpy and dynamic appearance. John Wheeler at Princeton
University thinks of this as a foamy, sub-structure to space where the geometry
of space twists and contorts so that far flung regions of space may suddenly
find themselves connected by 'wormholes' which constantly appear and dissappear
within 10(-43) seconds. Even as you are reading this article, this frenetic
activity is occurring in the hyper-microscopic domain, 100 billion billion
times smaller than the nucleus of an atom. For a comparison, the size of the
sun and the size of a single atom stand in about this same proportion. Although
Quantum Gravity effects are completely undetectable today at the atomic and
nuclear scale, during the Planck Era, macroscopic and microscopic worlds merged
and the Quantum Gravity of the microcosm suddenly became the Quantum Cosmology
of the macrocosm!

QUANTUM COSMOLOGY

As we approach the end of the Planck Era, the random appearance and
dissappearance of innumerable gravitons will eventually force us to give up the
concept of a specific geometry to 3-dimensional space. Instead, the geometry at
a given moment will have to be thought of as an average over all 3-dimensional
space geometries that are possible. Once again, the reason for this is that
particles are squeezed so closely together that we can now see individual
gravitons moving around in the space between them causing space to become
curved. We can no longer get away with saying that the space between two
quarks, for example, is flat. This is what we mean when we say that the
gravitational force between them is insignificant when compared to the other
three forces of Nature.

To make matters much worse, not only will Quantum Gravity not allow us to
calculate the exact 3-dimensional geometry to space but, at the Planck scale,
it will not allow us to simultaneously determine its exact geometry and precise
rate of change in time. What this means is that we may never be able to
calculate with any certainty exactly what the history of the universe was like
before 10-43 second. Today, the large-scale geometry of space is one of three
possible types: flat and infinite, negatively curved and infinite or positively
curved and finite. During the Planck Era, the 'large-scale' geometry was
contorted by wormholes and and infinite number of possibilities were possible.
To probe the history of the universe then would be like trying to trace your
ancestral roots if every human being on earth had a possibility of being one of
your parents. Now try to trace your family tree back a few generations! The
farther back in time you go, the greater are the number of possible ancestors
you could have had. An entirely new conception of what we mea n by 'a history
for the universe' will have to be developed. Even the concepts of space and
time will have to be completely re-evaluated in the face of the qua ntum
fluctuations of spacetime at the Planck Era!

THE BIRTH OF THE UNIVERSE

The picture that seems to emerge from using our sketchy outline of what Quantum
Gravity theory might look like is that as we approach the Planck Era, gravitons
are exchanged between quarks and electrons with increasingly higher energy and
in greater number. By the time we reach the end of the Planck Era at 10(-43)
second, gravitons will begin to carry as much energy as the other force
carriers (Gluons, IVBs and Photons). At still earlier times, a period of
complet e symmetry and unification between all the natural forces will ensue.
Only one super-unified force exists here (gravity) and only one kind of
particle dominates the activity of this age (Gravitons).

During the early 70's, the Russian physicists Ya. Zel'dovitch and A.
Starobinski of the USSR Academy of Science proposed that the rapidly changing
geometry of space during the Planck Era may actually have created all the
matter, anti-matter and radiation that existed soon after Creation. In their
picture of Creation, the rapidly changing geometry of space created particles
and anti-particles with masses of 10(19) GeV. This production of matter and
anti-matter removed energy from the enormous fluctuations occuring in the
geometry of space and eventually succeeded in damping them out altogether by
the end of the Planck Era. They also found that the rate of particle creation
increased as more and more particles were created.

Several recent studies by Physicists Edward Tryon of Hunter College, R. Brout,
F. Englert and E. Gunzig of the University of Brussels and david Atkatz and
Heinz Pagels of the Rockefeller University have shed additional light on what
Creation may have been like. Imagine if you can, nothing at all! This is the
primordial vacuum of space. There is complete darkness here, no light yet
exists. The number of dimensions to space was probably not the normal 3 that we
are so accustomed to but may have been as high as 11 according to Supergravity
theory! In this infinite emptiness, random fluctuations occurred that ever so
slightly changed the energy of the vacuum at various points in space.
Eventually, one of these fluctuations attained a critical energy and began to
grow. As it grew, very massive particles called leptoquarks and
anti-leptoquarks were created, causing the expansion to accelerate. This is
much like a ball rolling down a hill that moves slowly at first and then gains
momentum. The expansion of the proto-universe, in turn, caused still more
leptoquarks to be created. This furious cycle continued until, at long last,
the leptoquarks decayed into quarks, leptons (electrons, muons etc) and their
anti-particles and the universe emerged from the Planck Era. Particle creation
stopped once the fluctuations in the geometry of space subsided.

So, we are left with the remarkable possibility that, in the beginning, there
ex isted quite literally, nothing at all and from it emerged nearly all of the
matter and radiation that we now see. This process has been described by the
physicist Frank Wilczyk at the University of California, Santa Barbara by
saying, " The reason that there is something instead of nothing is that
nothing is unstable". A ball sitting on the summit of a steep hill needs but
the slightest tap to set it in motion. A random fluctuation in space was
apparently all that was required to unleash the incredable latent energy of
the vacuum, thus creating matter and energy and an expanding universe from
'nothing at all'.

The universe did not spring into being instantaneously but was created a little
bit at a time in a 'bootstrap' process. Once a few particles were created by
quantum fluctuations of the empty vacuum, it became easier for a few more to
appear and so, in a rapidly escalating process, the universe gushed forth from
nothingness.

How long did this take? The primordial vacuum could have existed for an
eternity before the particular fluctuation that gave rise to our universe
happened. Physicist Edward Tryon expresses this best by saying that " Our
universe is simply one of those things that happens from time to time".

The principles of Quantum Gravity may ultimatly force us to reconsider
questions like 'What happened before the Big Bang?' because they imply the
existence of something (time) that may not have any meaning at all. These
questions may be as empty of meaning as an explorer on the north pole asking,
'Which way is North?'. Only the complete theory of Quantum Gravity may tell us
how to ask the right questions!