Fundamental interaction
A fundamental interaction, or fundamental force, is one of the basic forces that act in the universe. Physicists recognise four: the strong force, the weak force, the electromagnetic force and the gravitational force. They act over different ranges and have different strengths.[1]
Strength and range
Gravity is the weakest of the four, but its range has no limit. The electromagnetic force also has an unlimited range and is many times stronger than gravity.[2] The weak and strong forces work only over very short distances and are important only at the level of subatomic particles.[3] Despite its name, the weak force is much stronger than gravity, though it is the weakest of the other three. The strong force is the strongest of all four.[4]
Force-carrier particles
Three of the four forces come from particles exchanging "force-carrier" particles, which belong to a wider group called bosons.[5] The strong force is carried by the gluon, the electromagnetic force by the photon, and the weak force by the W and Z bosons. A particle called the graviton is expected to carry gravity, but it has not been found.[6]
The Standard Model and gravity
The Standard Model of particle physics includes the electromagnetic, strong and weak forces and their carrier particles.[7] Gravity is not part of the Standard Model, because fitting it into the same framework has proved very difficult.[8] At the tiny scale of particles, however, the effect of gravity is so weak that it can be ignored.[9]
See also
References
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
There are four fundamental forces at work in the universe: the strong force, the weak force, the electromagnetic force, and the gravitational force. They work over different ranges and have different strengths.
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
Gravity is the weakest but it has an infinite range. The electromagnetic force also has infinite range but it is many times stronger than gravity.
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
The weak and strong forces are effective only over a very short range and dominate only at the level of subatomic particles.
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
Despite its name, the weak force is much stronger than gravity but it is indeed the weakest of the other three. The strong force, as the name suggests, is the strongest of all four fundamental interactions.
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
Three of the fundamental forces result from the exchange of force-carrier particles, which belong to a broader group called "bosons".
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
the strong force is carried by the "gluon", the electromagnetic force is carried by the "photon", and the "W and Z bosons" are responsible for the weak force. Although not yet found, the "graviton" should be the corresponding force-carrying particle of gravity.
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
The Standard Model includes the electromagnetic, strong and weak forces and all their carrier particles
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
gravity, is not part of the Standard Model, as fitting gravity comfortably into this framework has proved to be a difficult challenge.
- ↑ "The Standard Model". CERN. Retrieved 20 October 2026.
when it comes to the minuscule scale of particles, the effect of gravity is so weak as to be negligible.