Radialhastighetsmålingar

Radialhastighetsmålingar, often translated as radial velocity measurements, is a technique used primarily in astronomy to determine the velocity of celestial objects along the line of sight from the observer. This velocity is known as radial velocity. The principle behind radial velocity measurements relies on the Doppler effect. When a light source moves towards an observer, the emitted light waves are compressed, causing their wavelengths to shift towards the blue end of the spectrum (blueshift). Conversely, if the light source moves away from the observer, the light waves are stretched, shifting their wavelengths towards the red end of the spectrum (redshift).

Astronomers measure these shifts in the spectral lines of a star or galaxy. Each element has a unique spectral fingerprint, meaning it absorbs or emits light at specific, well-defined wavelengths. By observing how these characteristic lines are shifted in the spectrum of an object compared to their known laboratory wavelengths, the radial velocity can be calculated. The magnitude of the shift is directly proportional to the velocity. Instruments called spectrographs are used to disperse the light from celestial objects into its constituent wavelengths, allowing for precise measurement of these spectral shifts. Radial velocity measurements are crucial for various astronomical studies, including detecting exoplanets, determining the mass and motion of stars within galaxies, and understanding the expansion of the universe.