query: Is the speed of photon always $c_0$?
positive_passages.docid: 23937
positive_passages.text: What is the mechanism behind the slowdown of light/photons in a transparent medium?
negative_passages.docid: 3909
negative_passages.text: Does $E = mc^2$ apply to photons?
negative_passages.docid: 37345
negative_passages.text: Why can't massless particle exceed speed of light?
negative_passages.docid: 42816
negative_passages.text: Does entanglement have a speed or is it instantaneous
negative_passages.docid: 47988
negative_passages.text: Reflection At Speed of Light
negative_passages.docid: 141546
negative_passages.text: Time and distance in a photon's frame of reference
negative_passages.docid: 114913
negative_passages.text: What exactly is meant by the wavelength of a photon?
negative_passages.docid: 116871
negative_passages.text: Do photons take all paths or not?
negative_passages.docid: 10781
negative_passages.text: Accelerating particles to speeds infinitesimally close to the speed of light?
negative_passages.docid: 77372
negative_passages.text: "Speed" of Gravity and Speed of Light
negative_passages.docid: 53455
negative_passages.text: Relativistic speed/energy relation. Is this correct?
negative_passages.docid: 8367
negative_passages.text: What do physicists mean when they say "speed of light"?
negative_passages.docid: 28971
negative_passages.text: Do Photons Move in a Wave Like Pattern?
negative_passages.docid: 56065
negative_passages.text: How can the speed of light be a dimensionless constant?
negative_passages.docid: 99735
negative_passages.text: Are there any theoretical limits on the energy of a photon?
negative_passages.docid: 149674
negative_passages.text: Kinetic energy of a photon and Schwarzschild radius
negative_passages.docid: 59176
negative_passages.text: Amplitude of an electromagnetic wave containing a single photon