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Because of their dual nature as particles and waves, photons are often depicted as squiggly lines.
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Windows to the Universe original artwork by Randy Russell.

Photon

Light is very strange. Sometimes it is best to think of light as a series of waves. At other times, it is useful to think of light as a swarm of particles. When we think of light as particles, we call those particles of light "photons".

Photons are the carriers of all forms of electromagnetic (EM) radiation, not just light. The different types of EM radiation correspond to different amounts of energy per photon. Gamma ray and X-ray photons have the most energy, radio frequency photons have the least energy, while ultraviolet, infrared, and visible light photons have intermediate energies.

Photons travel at the speed of light, which is 299,792.458 kilometers per second (about 186,282.4 miles per second)! Photons don't have any mass, nor do they carry an electrical charge.

Last modified June 23, 2005 by Randy Russell.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF