Noun
change in the apparent frequency of a wave as observer and source move toward or away from each other
Source: WordNetAlthough "Doppler" has become synonymous with "velocity measurement" in medical imaging, in many cases it is not the frequency shift (Doppler shift) of the received signal that is measured, but the phase shift (when the received signal arrives). Source: Internet
By 1887, the photographic technique had improved to the point that it was possible to measure a star's radial velocity from the amount of Doppler shift in the spectrum. Source: Internet
Doppler effect of water flow around a swan main The Doppler effect (or the Doppler shift) is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. Source: Internet
In 1912 Vesto Slipher measured the first Doppler shift of a " spiral nebula " (spiral nebula is the obsolete term for spiral galaxies), and soon discovered that almost all such nebulae were receding from Earth. Source: Internet
Simultaneity in the Doppler shift calculation It may be difficult to see where simultaneity came into the Doppler shift calculation, and indeed the calculation is often preferred because one does not have to worry about simultaneity. Source: Internet
During the trip, both the traveler and Earth keep sending signals to each other at a constant rate, which places Langevin's story among the Doppler shift versions of the twin paradox. Source: Internet