Definition
A photon is an elementary particle that is the basic unit (quantum) of light and of all other forms of electromagnetic radiation. The photon has no rest mass and no charge and by definition travels at the speed of light. It is characterized by very few parameters: its energy and its polarization state. Its energy E is directly related to the frequency ν of the electromagnetic wave it is associated with, through the relation E = hν, where h is the Planck constant.
As regards fundamental interactions, the photon is the quantum of the electromagnetic field. This means that it mediates the interaction between charged particles, that is, the electromagnetic force.
Photons belong to the broad family of bosons, which are described as the carriers of the various fundamental interactions and are a necessary consequence of physical laws having particular symmetries at every point in space-time. Because it is made of bosons, a collection of photons can present very specific properties,...
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© 2014 Springer-Verlag Berlin Heidelberg
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Rouan, D. (2014). Photon. In: Amils, R., et al. Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-27833-4_1201-2
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DOI: https://doi.org/10.1007/978-3-642-27833-4_1201-2
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Publisher Name: Springer, Berlin, Heidelberg
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