The Four Fundamental Forces of the Universe
The Four Fundamental Forces
The familiar force of gravity pulls you down into your seat, toward the Earth’s center. You feel it as your weight. Why don’t you fall through your seat? Another force, electromagnetism, holds the atoms of your seat together, preventing your atoms from intruding on those of your seat.
The remaining two forces work at the atomic level, which we never directly feel, despite our being made of atoms. The strong force holds the nucleus together. The weak force is responsible for radioactive decay, specifically, β-decay, in which a neutron within the nucleus changes into a proton and an electron, and the electron is then ejected from the nucleus.