What is the Red Shift?
Light and sound waves are described in terms of their spectra. When an ambulance approaches, the sound appears to have higher pitch (higher frequency). The pitch is lower (lower frequency) when it is moving away. This effect, which occurs for all wave motion, including sound and light waves, is called the Doppler effect. In the case of light, when a source is moving away, its light appears redder (longer wavelength, lower frequency) than it actually is. Red Shift is the observation in 1929, by Edwin Hubble, that most galaxies have Doppler shifts toward the red end of the spectrum, indicating that the galaxies are receding from the Earth. Dimmer galaxies are probably further away from brighter galaxies. Using estimated distances based on relative brightness and the observed Doppler red shifts, Hubble discovered that galaxies that exhibit the greatest red shifts are the most distant (dimmest). The observations show that all galaxies are moving away from us. An expanding universe can adeq
Light and sound waves are described in terms of their spectra. When an ambulance approaches, the sound appears to have higher pitch (higher frequency). The pitch is lower (lower frequency) when it is moving away. This effect, which occurs for all wave motion, including sound and light waves, is called the Doppler effect. In the case of light, when a source is moving away, its light appears redder (longer wavelength, lower frequency) than it actually is. Red Shift is the observation in 1929, by Edwin Hubble, that most galaxies have Doppler shifts toward the red end of the spectrum, indicating that the galaxies are receding from the Earth. Dimmer galaxies are probably further away from brighter galaxies. Using estimated distances based on relative brightness and the observed Doppler red shifts, Hubble discovered that galaxies that exhibit the greatest red shifts are the most distant (dimmest). The observations show that all galaxies are moving away from us. An expanding universe can adeq
