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Cherenkov radiation ( / tʃəˈrɛŋkɒf / [1]) (also known as Čerenkov or Cerenkov radiation [2]) is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium (such as distilled water) at a speed greater than the phase velocity (speed of propagation of a wavefront in a medium) of light ...
No-communication theorem. In physics, the no-communication theorem or no-signaling principle is a no-go theorem from quantum information theory which states that, during measurement of an entangled quantum state, it is not possible for one observer, by making a measurement of a subsystem of the total state, to communicate information to another ...
Air is thin enough that in the Earth's atmosphere radio waves travel very close to the speed of light. The wavelength is the distance from one peak (crest) of the wave's electric field to the next, and is inversely proportional to the frequency of the wave. The relation of frequency and wavelength in a radio wave traveling in vacuum or air is.
Superluminal communication is a hypothetical process in which information is conveyed at faster-than-light speeds. The current scientific consensus is that faster-than-light communication is not possible, and to date it has not been achieved in any experiment. Superluminal communication other than possibly through wormholes is likely impossible ...
In the context of this article, "faster-than-light" means the transmission of information or matter faster than c, a constant equal to the speed of light in vacuum, which is 299,792,458 m/s (by definition of the metre) [3] or about 186,282.397 miles per second. This is not quite the same as traveling faster than light, since:
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1] : 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and ...
Theorized. 1967. A tachyon ( / ˈtækiɒn /) or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are inconsistent with the known laws of physics. [ 1][ 2] If such particles did exist they could be used to send signals faster than light.
Radio frequency. Radio frequency ( RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency [1] range from around 20 kHz to around 300 GHz. This is roughly between the upper limit of audio frequencies and the lower limit of infrared ...