Assertion: photon | /r/CapableOf | move at the speed of light
Facets:
value: always
type: TEMPORAL
value: exactly
type: DEGREE
Source sentences:
text: and they always move at the speed of light in vacuum, 299792458 m/s.
text: It is wave and particle at the same time and always moves with the speed of light.
text: Further, we know that photons are massless and thus travel at exactly the speed of light.
text: Because photons always move at the speed of light, the spin is best expressed in terms of the component measured along its direction of motion, its helicity, which must be ±ħ.