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Monday, 16 November 2009 08:06 |
- Matter is effected by forces or interactions (the terms are interchangeable)
- there are four fundamental forces in the Universe:
- gravitation (between particles with mass)
- electromagnetic (between particles with charge/magnetism)
- strong nuclear
 force (between quarks)
- weak nuclear force (that changes quark types)
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The first two you are familiar with, gravity is the attractive force between all matter, electromagnetic force describes the interaction of charged particles and magnetics. Light ( photons) is explained by the interaction of electric and magnetic fields.
The strong force binds quarks into protons, neutrons and mesons, and holds the nucleus of the atom together despite the repulsive electromagnetic force between protons. The weak force controls the radioactive decay of atomic nuclei and the reactions between leptons (electrons and neutrinos).
Current physics (called quantum field theory) explains the exchange of energy in interactions by the use of force carriers, called bosons. The long range forces have zero mass force carriers, the graviaton and the photon. These operate on scales larger than the solar system. Short range forces have very massive force carriers, the W+, W- and Z for the weak force, the gluon for the strong force. These operate on scales the size of atomic nuclei.
So, although the strong force has the greatest strength, it also has the shortest range.
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