Wednesday, 8 July 2009


One of the reasons our physics is incomplete during the Planck era is a lack of understanding of the
unification of the forces of Nature during this time. At high energies and temperatures, the forces of
Nature become symmetric. This means the forces resemble each other and become similar in
strength, i.e. they unify.

An example of unification is to consider the interaction of the weak and electromagnetic forces. At
low energy, photons and W,Z particles are the force carriers for the electromagnetic and weak forces.
The W and Z particles are very massive and, thus, require alot of energy (E=mc2). At high energies,
photons take on similar energies to W and Z particles, and the forces become unified into the
electroweak force.
There is the expectation that all the nuclear forces of matter (strong, weak and electromagnetic) unify
at extremely high temperatures under a principle known as Grand Unified Theory, an extension of
quantum physics using as yet undiscovered relationships between the strong and electroweak forces.
The final unification resolves the relationship between quantum forces and gravity (supergravity).
In the early Universe, the physics to predict the behavior of matter is determined by which forces are
unified and the form that they take. The interactions just at the edge of the Planck era are ruled by
supergravity, the quantum effects of mini-black holes. After the separation of gravity and nuclear
forces, the spacetime of the Universe is distinct from matter and radiation.
Spacetime Foam :
The first moments after the Planck era are dominated by conditions were spacetime itself is twisted
and distorted by the pressures of the extremely small and dense Universe.

Most of these black holes and wormholes are leftover from the Planck era, remnants of the event
horizon that protected the cosmic singularity. These conditions are hostile to any organization or
structure not protected by an event horizon. Thus, at this early time, black holes are the only units
that can survive intact under these conditions, and serve as the first building blocks of structure in the
Universe, the first `things' that have individuality.
Based on computer simulations of these early moments of the Universe, there is the prediction that
many small, primordial black holes were created at this time with no large black holes (the Universe
was too small for them to exist). However, due to Hawking radiation, the primordial black holes from
this epoch have all decayed and disappeared by the present-day.
Matter arises at the end of the spacetime foam epoch as the result of strings, or loops in spacetime.
The transformation is from ripping spacetime foam into black holes, which then transmute into
elementary particles. Thus, there is a difference between something of matter and nothing of
spacetime, but it is purely geometrical and there is nothing behind the geometry. Matter during this
era is often called GUT matter to symbolize its difference from quarks and leptons and its existence
under GUT forces.

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