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Physics - Formulas - Doppler Shift

A Doppler shift is a phenomenon of a change in frequency based on the observers point of view. The most common analogy of this is standing on the side of the road and listen to a passing car. As the car approaches, there is a definitive sound. As the car passes, the sound changes to a lower frequency. This is called a Doppler Shift. There are two types of Doppler shifts:
  • Red-Shift or a shift of frequency to a lower wavelength (away from the observer)
  • Blue-Shift or a shift of frequency to a higher wavelength (toward the observer)

Anything that emits wavelengths - light, radio, gamma rays, and the rest of the E-M Band - and changes frequency due to movement, a Doppler shift can be measured. This is the equation:

By measuring the Doppler shift of an object, it is possible to measure the velocity of that object:

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