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Galactic Odyssey Movie: text

Force Separation

In the so-called "Standard Model" of matter, physicists postulate that just four fundamental forces govern the behavior the cosmos. The most familar to us is, gravity, the long-range force that dominates the interactions of matter across astronomic al distances. Then there's the electromagnetic force, also long-range, but it manifests in the inner realm of the atom, keeping electrons inside their nuclear orbits. The other two forces, the strong nuclear force that binds the particles th at make up the nuclei of atoms, and the weak nuclear force underlying some types of radioactive decay -- both these forces operate only over very short, subatomic distances.

Physicists also theorize that all four forces are carried by particles named bosons which interact at sufficient energies. At high enough temperatures, these particles become indistinguishable, as do the forces they carry.

In the Grand Unification Theory (GUT) proposed in the 1970's, the strong, weak and electromagnetic forces merge at the mind-boggling temperatures that existed 10^-35 seconds after the Big Bang. Yet gravity remains separate. Looking still further ba ckwards in time, at 10^-43 seconds, gravity too merges with the other forces into one force. Scientists are still struggling to work out the underlying physics of such a Theory of Everything (TOE).

The diagram depicts the separation forces as a function of energy measured billions of electron volts (Gev).

An electron volt is a unit of energy that is related to the wavelength of radiation, which can range from light to X-rays or even a beam of electrons, as employed by an electron microscope. The higher the temperature, the shorter the wavelength of the rad iation, and the larger the number of electron volts of energy carried by a single particle or photon of that radiation.

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NCSA. Last modified, 9/30/95