Monday, 14 March 2011
CASE 237 - The laws of physics
Characteristics of the Laws of Physics:
Universal. The laws work in all places and all times of the universe.
Absolute. They depend on nothing else, not on the observer, not on the particular "state" of the universe.
Eternal. Their truth is timeless and eternal
Omnipotent. Nothing is immune to them; they are "all-powerful."
(loosely) Omniscient. The laws "know" the conditions of each physical system when they "command" the systems how to behave
The laws of pysics
These qualities suggest an independent, transcendent existence of these laws.
indeed, physicists speak of planets "obeying" Newton's laws, as if the laws are "out there."
The Grand Quest for a "Theory of Everything"
One of the great quests of modern physics has been to find a theory that will unify the four fundamental forces of nature:
the electromagnetic force
the weak force
the strong force
This quest is based in part on an aesthetic conviction that such an elegant symmetry and ultimate simplicity must exist in nature.
the Glashow-Weinberg-Salam Electroweak theory in the late 1960's unified the electromagnetic force and weak force.
the general shape or outline of a theory to unify the Electroweak force and the Strong Nuclear force -- a Grand Unified Theory" (GUT) -- seems clear, although the details are still not worked out.The term "Standard Model" refers to the two present theories which are the foundation of our knowledge of elementary "particles:"Electroweak Theory. Quantum Chromodynamics, the theory of the Strong Nuclear Force. The best theory of the gravitational force we have today is Einstein's General Theory of Relativity. Most of the classical work in cosmology, including the "Big Bang" and the "initial singularity" at time = 0 that we will discuss today arises from Einstein's General Theory of Relativity, the General Theory of Relativity however does not include the findings of quantum physics, and hence is still not a complete theory of the gravitational force. A theory incorporating quantum physics effects into Einstein's General Theory still eludes physics, and so far, proposed theories, such as Hawking-Hartle Theory of Quantum Gravity, are still quite speculative the shape of a theory that possesses the properties that might make it a candidate for a Quantum Theory of Gravity or as a Theory of Everything is actively being pursued. Candidates include:
supersymmetry theories supersymmetry theories with "local supersymmetry" are candidates for a quantum theory of gravity and are often called "supergravity" string theory with supersymmetry = supersymmetric string theory = superstring theory
Whatever the final theory, physicist are convinced that:
“The Theory of Everything … would be much more than just a catalogue of physical laws. It would constitute a truly unified description of the material universe, weaving an intricate web of interconnections between its component parts, each one essential to the overall consistency of the whole . . . The Theory of Everything would be utterly compelling in structure, symmetry and elegance”