The medicine worked because the photon–the quantum bundle of light and the carrier of the electromagnetic force–has no mass.
When the gamma rays enter the sleeve, they interact with that photon gas, annihilating into electron-positron pairs.
Among his pastimes was designing a solar-power car, the photon Torpedo.
Or there may be an inelastic collision, when the photon hits an atom and knocks out an electron—the old photoelectric effect.
"Well, you know what happens when a photon comes in contact with the atomic structure of matter," Kato said.
Or, the photon may be retained for a while and emitted again relatively unchanged—the effect observed in luminous paint.
There were hundreds of scintillations, each caused by a nuclear particle or photon striking the screen.
photon pho·ton (fō'tŏn')
The quantum of electromagnetic energy, generally regarded as a discrete particle having zero mass, no electric charge, and an indefinitely long lifetime.
The subatomic particle that carries the electromagnetic force and is the quantum of electromagnetic radiation. The photon has a rest mass of zero, but has measurable momentum, exhibits deflection by a gravitational field, and can exert a force. It has no electric charge, has an indefinitely long lifetime, and is its own antiparticle. See Note at electromagnetic radiation. See Table at subatomic particle.