query: Speed of light in vacuum - is it really a constant and what is the accurate value?
positive_passages.docid: 91265
positive_passages.text: Has the speed of light changed over time?
negative_passages.docid: 17152
negative_passages.text: Do all massless particles (e.g. photon, graviton, gluon) necessarily have the same speed $c$?
negative_passages.docid: 67127
negative_passages.text: Does the speed of light vary in non-inertial frames?
negative_passages.docid: 106021
negative_passages.text: How wrong are the classical Maxwell's equations (as compared to QED)?
negative_passages.docid: 81880
negative_passages.text: How can a photon have no mass and still travel at the speed of light?
negative_passages.docid: 8367
negative_passages.text: What do physicists mean when they say "speed of light"?
negative_passages.docid: 974
negative_passages.text: Speed of light in a gravitational field?
negative_passages.docid: 45953
negative_passages.text: How can I explain the scientific basis of the constant speed of light to a $c$-decay proponent?
negative_passages.docid: 120621
negative_passages.text: Speed of Dark experiment, does it *really* travel faster than light?
negative_passages.docid: 57961
negative_passages.text: Some doubts about photons
negative_passages.docid: 8077
negative_passages.text: Photons in expanding space: how is energy conserved?
negative_passages.docid: 132106
negative_passages.text: Why does the speed of light $c$ have the value it does?
negative_passages.docid: 89837
negative_passages.text: Speed of light when accelerating
negative_passages.docid: 12597
negative_passages.text: Does the speed of medium affect the path of light?
negative_passages.docid: 10781
negative_passages.text: Accelerating particles to speeds infinitesimally close to the speed of light?
negative_passages.docid: 141791
negative_passages.text: What would be the associated wavelength of the particle if its velocity is zero?
negative_passages.docid: 111469
negative_passages.text: De Broglie wavelength, frequency and velocity - interpretation