Astrophysics (index)

Doppler Shift

(Doppler Effect)
(wave frequency difference due to relative velocity difference with source)

A Doppler Shift (or Doppler Effect), in astronomy, is typically a change in Electromagnetic Radiation Frequency and Wavelength due to a Radial Velocity between the observer and the observed. It is a general property of waves, and is popularly known as the reason the sound of a passing vehicle has a higher tone as the vehicle approaches and lower when it has passed.

For EMR, the relationship between wavelength and relative velocity is:

δf = ——
  • δf - change in frequency.
  • δv - relative velocity.
  • c - speed of the waves, e.g., speed of light.

Doppler shifts can also be caused by Gravity, due to General Relativity, offering another method of observation and analysis.


Referenced by:
Binary Star
Dark Matter
Velocity Dispersion (σ)
Double-Line Spectroscopic Binary
Extra Solar Planet
Galactic All-Sky Survey (GASS)
Kepler Radius
Kinematic Distance
Line Shape Function
Position-Position-Velocity Space (PPV)
Quenched Galaxy
Radial Velocity
Spectroscopic Binary
Stellar Mass Determination
Stellar Radius Determination
Stellar Rotation
Tully-Fisher Relation (TFR)
21cm Line