Wednesday 4 July 2012

String Theory simplified

The “theory of everything,” includes such unusual concepts as superstrings, branes, and extra dimensions. Scientists are hopeful that string theory will unlock one of the biggest mysteries of the universe, namely how gravity and quantum physics fit together.

String theory is a work in progress, so trying to pin down exactly what the science is, or what its fundamental elements are, can be kind of tricky.

The basic are

•All objects in our universe are composed of vibrating filaments (strings) and membranes (branes) of energy.

•String theory attempts to reconcile general relativity (gravity) with quantum physics.

•A new connection (called supersymmetry) exists between two fundamentally different types of particles, bosons and fermions.

•Several extra (usually unobservable) dimensions to the universe must exist.

There are also other possible string theory features, depending on what theories prove to have merit in the future. Possibilities include:

•A landscape of string theory solutions, allowing for possible parallel universes.

•The holographic principle, which states how information in a space can relate to information on the surface of that space.

•The anthropic principle, which states that scientists can use the fact that humanity exists as an explanation for certain physical properties of our universe.

•Our universe could be “stuck” on a brane, allowing for new interpretations of string theory.

Key Events in String Theory History
Although string theory is a young science, it has had many notable achievements. What follows are some landmark events in the history of string theory:

1968: Gabriele Veneziano originally proposes the dual resonance model.

1970: String theory is created when physicists interpret Veneziano’s model as describing a universe of vibrating strings.

1971: Supersymmetry is incorporated, creating superstring theory.

1974: String theories are shown to require extra dimensions. An object similar to the graviton is found in superstring theories.

1984: The first superstring revolution begins when it’s shown that anomalies are absent in superstring theory.

1985: Heterotic string theory is developed. Calabi-Yau manifolds are shown to compactify the extra dimensions.

1995: Edward Witten proposes M-theory as unification of superstring theories, starting the second superstring revolution. Joe Polchinski shows branes are necessarily included in string theory.

1996: String theory is used to analyze black hole thermodynamics, matching earlier predictions from other methods.

2012: a glimmer of the Higg Boson. Keep your fingers crossed guy.

Steven Hawkin bet $100 bucks against it…

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