A New Theory Regarding the Origin of the Universe?
by Wayne McDonald
For over 50 years the Big Bang Theory has reigned unchallenged as
the most complete theory regarding the origin and subsequent
development of the Universe. However, its place in theoretical
physics and cosmology is being seriously challenged by a new theory
whose thesis is an event referred to as the “Big Bounce.”
In a letter to be published in the August, 2007 issue of Nature
Physics 1 Martin Bojowald of the Institute for Gravitational Physics
and Geometry at Pennsylvania State University will announce that he
has developed a new model of the early Universe that differs from
the currently accepted model in one “minor” respect: there is no Big
Bang! Instead, he proposes that there was an event which has been
dubbed the “Big Bounce” rather than the “Big Bang.”
Simplified diagram of the oscillating universe
theory showing the repeating collapse-expansion pattern. CREDIT:
University of Rochester (NY).
Bojowald’s theory is derived from the equations of Loop Quantum
Gravity (LQG), a mathematical model that attempts to reconcile both
gravity and quantum mechanics within a single theory. In this new
application of LQG the theory begins by stating that the Universe,
over tremendously long periods of time, goes through a repeating
cycle of expansion, contraction, and rebirth. In Bojowald’s model
the Universe eventually contracts to a point that is both very hot
and very dense but does not approach the infinite density and
temperature that preceded the Big Bang. Instead, the Universe
collapses to a critical point, well short of the singularity of the
Big Bang Theory. Once this critical point is reached, the “Big
Bounce” occurs and the Universe re-expands.
Although not explicitly stated in Bojowald’s paper, the Big
Bounce does away with the need for a particular bit of “fine tuning”
regarding the Big Bang Theory, a period of time called the
inflationary era.
As the Big Bang theory was being developed it became obvious that
a major problem had arisen: the Universe was too big to be explained
by the General Theory of Relativity. Rather than scrap the entire
theory its advocates hypothesized that, very shortly after instant
of the Big Bang, the Universe expanded faster than the speed of
light due to some “breakdown” in relativity brought on by the
extreme conditions present during that period.
If, however, the Big Bang is replaced by a Big Bounce, the
theory’s predictions seem to agree with the observed current
dimensions of the Universe.
The loop quantum gravity model also provides that the new
universe is not a mere “carbon copy” of its predecessor due to
quantum uncertainties that are manifest during the periods
immediately prior to and after the Big Crunch. In other words, the
previous universe may have developed with an abundance of antimatter
over matter but the Big Bounce “reset the stage” and our Universe
developed with its familiar dominance of matter over antimatter.
As with practically all scientific theories Bojowald’s Big Bounce
is built from, and supported by, the works of other theoretical
physicists; most notably the research of Baum and Frampton into
cyclic, or repeating, universes. 2 - 4 And, as with any other
theory, only time will tell if the Big Bounce will unseat the Big
Bang as the correct description of the events that unfolded in the
very young Universe.
Notes
1. Bojowald, Martin (2007): ‘What happened before the Big Bang?
“Nature Physics, Published online: 01 July 2007; | doi:
10.1038/nphys6
2. Baum, Lauris and Frampton, Paul (2006): “Deflation at
Turnaround for Oscillatory Cosmology
arXiv: astro-ph/0608138v1
3. Frampton, Paul (2007): “Cyclic Universe and Infinite Past”
arXiv: 0705.2730
4. ____________ (2006): “On Cyclic Universes”
arXiv: astro-ph/0612243
©2007 Wayne McDonald
All Rights Reserved.
Reprinted with Permission
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