How do astronomers utilize spectral lines to calculate radial velocity?

Answer

By measuring how far established spectral lines have shifted from their known stationary locations.

Spectral lines have precise, known positions for stationary sources; measuring the deviation (shift) of these lines allows scientists to calculate the velocity along the line of sight.

How do astronomers utilize spectral lines to calculate radial velocity?

#Videos

Detecting Exoplanets: Radial Velocity Method - YouTube

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