Mondo Knows Facts
Light particles possess energy but no rest mass
Photons travel at the speed of light because they carry momentum without rest mass
In quantum electrodynamics, photons are elementary particles that mediate the electromagnetic force. Although a photon has zero rest mass, it carries relativistic momentum proportional to its frequency. This momentum allows light rays to exert microscopic radiation pressure on solar sails and atomic targets.
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Tags: physics, photons, quantum
Light particles possess energy but no rest mass: the short answers
- Where does this come from, and can I check it?
- Photons travel at the speed of light because they carry momentum without rest mass. The figure is taken from NIST, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
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