A quantum of light, also seen as a force-carrying particle.
Photon Term Timeline in A Brief History of Time
The timeline below shows where the term Photon appears in A Brief History of Time. The colored dots and icons indicate which themes are associated with that appearance.
...small, atomic scale, electromagnetic forces dominate all activity. This force arises from the exchange of photons. Real photons are made when electrons move along the set orbits of an atom. We... (full context)
...infinitely hot. Right after the big bang the universe would have been made up of photons, electrons, and neutrinos, along with their anti-particles, and some protons and neutrons. As the universe... (full context)
...the different pressures applied to metal plates created by discrepancies of the density of virtual photons between and outside the plates. Within the plates, the photons would only occur in the... (full context)