|English: Interaction of quarks through color charge within a neutron. Svg available. Español: Interacción de los quarks de un neutrón por su carga de color. Disponible el svg. (Photo credit: Wikipedia)|
There are 4 fundamental forces that have been identified. In our present Universe they have rather different properties.
|English: Quarks in protons in RFT (Photo credit: Wikipedia)|
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.
English: The quark structure of the proton. There are two up quarks in it and one down quark. The strong force is mediated by gluons (wavey). The strong force has three types of charges, the so-called red, green and the blue. Note that the choice of green for the down quark is arbitrary; the "color charge" is thought of as circulating among the three quarks. (Photo credit: Wikipedia)