The Fundamental Forces
What are the fundamental forces?
- Gravity: Holds stars together. The weakest force between fundamental entities. Example: calculate the ratio of the gravitational force to the electrical force between two electrons. Answer ~10-42 !
- Electromagnetic: Holds atoms together. Much stronger than gravity (and the weak force below) Example: atoms, molecules, solids, …..
- Strong: Holds the nucleus together. The strongest force at small distances. Example: mesons formed from quarks hold together protons in nucleus – recently “top quark” produced at Fermilab!
- Weak: Allows for transmutation of elements. Stronger than gravitational force at very short distances. Example: nuclear beta decay
What does the “Standard Model” have to say about these forces?
- It gives the form of the weak, electromagnetic and strong forces in terms of the fundamental entities (quarks & leptons) mediated by various bosons.
- So far no theory has been successful to include gravity along with the other forces!