| Research into the atom's nucleus has uncovered a variety of subatomic particles, including quarks and gluons. |
| Atoms may acquire energy that excites electrons by random thermal collisions, collisions with subatomic particles, or by absorbing a photon. |
| Cosmic neutrinos are extremely high energy subatomic particles, like protons and electrons, but neutrinos have no electrical charge. |
| To study subatomic particles, physicists build giant accelerators that smash the particles together. |
| Note that subatomic particles sometimes have antiparticles, with opposite charge and spin, that are the same ones going backwards in time. |
| The big bang theory of cosmology asserts that the universe was once a very small and very hot soup of energetic subatomic particles. |
