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  2. Doppler effect - Wikipedia

    en.wikipedia.org/wiki/Doppler_effect

    [1] [2] [3] The Doppler effect is named after the physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach ...

  3. Relativistic Doppler effect - Wikipedia

    en.wikipedia.org/wiki/Relativistic_Doppler_effect

    The relativistic Doppler effect is the change in frequency, wavelength and amplitude [1] of light, caused by the relative motion of the source and the observer (as in the classical Doppler effect, first proposed by Christian Doppler in 1842 [2]), when taking into account effects described by the special theory of relativity.

  4. Relativistic beaming - Wikipedia

    en.wikipedia.org/wiki/Relativistic_beaming

    Only a single jet is visible in M87. Two jets are visible in 3C 31.. In physics, relativistic beaming (also known as Doppler beaming, Doppler boosting, or the headlight effect) is the process by which relativistic effects modify the apparent luminosity of emitting matter that is moving at speeds close to the speed of light.

  5. Wave - Wikipedia

    en.wikipedia.org/wiki/Wave

    The Doppler effect or Doppler shift is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. [18] It is named after the Austrian physicist Christian Doppler , who described the phenomenon in 1842.

  6. Doppler tracking - Wikipedia

    en.wikipedia.org/wiki/Doppler_tracking

    Doppler tracking.The Doppler effect allows the measurement of the distance between a transmitter from space and a receiver on the ground by observing how the frequency received from the transmitter changes as it approaches the transmitter, is overhead, and moves away.

  7. Doppler broadening - Wikipedia

    en.wikipedia.org/wiki/Doppler_broadening

    A particular case is the thermal Doppler broadening due to the thermal motion of the particles. Then, the broadening depends only on the frequency of the spectral line, the mass of the emitting particles, and their temperature , and therefore can be used for inferring the temperature of an emitting (or absorbing) body being spectroscopically ...

  8. Doppler cooling - Wikipedia

    en.wikipedia.org/wiki/Doppler_cooling

    The Doppler temperature is the minimum temperature achievable with Doppler cooling. When a photon is absorbed by an atom counter-propagating to the light source, its velocity is decreased by momentum conservation. When the absorbed photon is spontaneously emitted by the excited atom, the atom receives a momentum kick in a random direction.

  9. Galilean invariance - Wikipedia

    en.wikipedia.org/wiki/Galilean_invariance

    Galilean invariance or Galilean relativity states that the laws of motion are the same in all inertial frames of reference. Galileo Galilei first described this principle in 1632 in his Dialogue Concerning the Two Chief World Systems using the example of a ship travelling at constant velocity, without rocking, on a smooth sea; any observer below the deck would not be able to tell whether the ...