Doppler shift
Motion alters frequency
Doppler shift is the change in frequency of a wave when the source and observer are moving relative to each other.
An ambulance siren sounds higher-pitched as it approaches and lower as it recedes—the sound waves compress ahead and stretch behind.
The same principle applies to light: astronomers measure the redshift of distant galaxies to determine they're moving away from us.
The Doppler shift indicated the star was approaching at high velocity.
- bluePrimary color; also sad
- frequencyRate of recurrence
- police radarTraffic enforcement sensor
- spectral linesDiscrete wavelength emission patterns
- wavelengthSpatial repetition interval
binary stars · red · spectrum · train · radar gun · ambulance siren · light · light waves · sound waves · wave · siren · signal · horn · whistle · spectroscopy · universe · compression · astronomy
- GPSsatellite, GPS navigation, GPS tracking, latitude, GPS receivers
- Doppler effect
- stellar motionorbit, trajectory, orbital velocity, angular momentum, orbital mechanics
- stellar spectroscopyspectral lines, spectroscopy, spectrograph, spectrometer, spectroscope
- weather radarweather radar, radar beam, radar sweep, reflectivity, radar imagery
- soundsound, sound waves, echoes, acoustics, vibrations