Noun
a quantum of electromagnetic radiation; an elementary particle that is its own antiparticle
Source: WordNetLight is something like raindrops - each little lump of light is called a photon - and if the light is all one color, all the "raindrops" are the same. Richard Feynman
When a photon comes down, it interacts with electrons throughout the glass, not just on the surface. The photon and electrons do some kind of dance, the net result of which is the same as if the photon hit only on the surface. Richard Feynman
If a little kid ever asks you just why the sky is blue, you look him or her right in the eye and say, "It's because of quantum effects involving Rayleigh scattering combined with a lack of violet photon receptors in our retinae." Phil Plait
Life invented it first, Zoe thought, like so many other things. Like eyes: Turning photon impacts into neurochemical events with such subtlety that a frog can target a fly and a man can admire a rose. Robert Charles Wilson
Each cell sends electrical pulses to other cells, up to hundreds of times per second. If you represented each of these trillions and trillions of pulses in your brain by a single photon of light, the combined output would be blinding. David Eagleman
The question of how the eye works - that is, what happens when a photon of light first impinges on the retina - simply could not be answered at that time. Michael Behe