The Fundamental
Forces of Nature
There are 4 fundamental forces that have been identified. In our present Universe they have rather different properties.
Properties of the Fundamental Forces
- The strong interaction is very strong, but very short-ranged. It acts only over ranges of order 10-13 centimeters and is responsible for holding the nuclei of atoms together. It is basically attractive, but can be effectively repulsive in some circumstances.
- The electromagnetic force causes electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It is long-ranged, but much weaker than the strong force. It can be attractive or repulsive, and acts only between pieces of matter carrying electrical charge.
- The weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and, as its name indicates, it is very weak.
- The gravitational force is weak, but very long ranged. Furthermore, it is always attractive, and acts between any two pieces of matter in the Universe since mass is its source.
Occasionally, physicists have postulated the existence of a fifth force in addition to the four known fundamental forces.
See the full astronomy cources and other science programs on the www and TV Science channel and Discovery stations to bring you up to date on the thinking!
http://csep10.phys.utk.edu/astr162/lect/cosmology/forces.html
Posted by holybodymindandsoul
at 7:19 AM EDT
Updated: Tuesday, 16 August 2011 4:14 AM EDT
