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Tuesday, 24 November 2009 02:01 |
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In the early Universe, pressures and temperature prevented the permanent
establishment of elementary particles. Even quarks and leptons were
unable to form stable objects until the Universe had cooled beyond the
supergravity phase. If the fundamental building blocks of Nature
(elementary particles) or spacetime itself were not permanent then what
remained the same? The answer is symmetry.
Often symmetry is thought of as a relationship, but in fact it has its
own identical that is preserved during the chaos and flux of the early
Universe. Even though virtual particles are created and destroyed,
there is always a symmetry to the process. For example, for every
virtual electron that is formed a virtual positron (anti-electron) is
also formed. There is a time symmetric, mirror-like quality to every
interaction in the early Universe.
How important is symmetry? When Nobel Prize winning physicist Richard Feymann was asked to
summarize the more important aspect of modern  science in one sentence he said "The Universe is
made of atoms". When asked what he would say for a second sentence, he said "Symmetry
underlies the laws of Nature."
- symmetry provides order to the early chaos, but also provides key moments when the Universe undergoes radical
change as symmetries are broken
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Symmetry also leads to conservation laws, and conservation laws limit the
possible interactions between particles. Those imaginary processes
that violate conservation laws are forbidden. So the existence of symmetry
provides a source of order to the early Universe.
Pure symmetry is like a spinning coin. The coin has two states, but
while spinning neither state is determined, and yet both states exist.
The coin is in a state of both/or. When the coin hits the floor the
symmetry is broken (its either heads or tails) and energy is released in
the process (the noise the coin makes as it hits the ground). |
- symmetry breaking lead to phase changes, particular moments with the Universe adopts new properties
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The effect of symmetry breaking in the early Universe was a series of
phase changes, much
like when ice melts to water or water boils to stream. A phase
change is the dramatic change in the internal order of a substance.
When ice melts, the increased heat breaks the bonds in the lattice of
water molecules, and the ice no longer holds its shape. Phase change
in the early Universe occurs at the unification points of fundamental
forces. The decoupling of those forces provides the energy input for
the phase change.
With respect to the Universe, a phase change during symmetry breaking is
a point where the characteristics and the properties of the Universe
make a radical change. At the supergravity symmetry breaking, the
Universe passed from the Planck era of total chaos to the era of
spacetime foam. Spacetime was acquired during the phase transition.
During the GUT symmetry breaking, mass and spacetime separated and
particles came into existence. |
- at each symmetry break chaos increases, entropy marches forward
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Notice that as symmetry breaks, there is less order, more chaos. The
march of entropy in the Universe apples to the laws of Nature as well as
matter. The Universe at the time of the cosmic singularity was a time
of pure symmetry, all the forces had equal strength, all the matter
particles had the same mass (zero), spacetime was the same everywhere
(although all twisted and convolved). |
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