College Physics II – Mechanics, Sound, Oscillations, and Waves
Definition
Red shift is the phenomenon where the wavelength of light or other electromagnetic radiation from an object increases as it moves away from the observer. This results in a shift toward the red end of the spectrum.
congrats on reading the definition of red shift. now let's actually learn it.
Red shift occurs due to the Doppler Effect when an object emitting light is moving away from the observer.
In sound, a similar effect occurs where lower frequencies (longer wavelengths) are heard as the source moves away.
The magnitude of red shift can be used to determine the speed at which an astronomical object, like a galaxy, is receding from Earth.
Red shift provides crucial evidence for the expansion of the universe and supports the Big Bang theory.
The formula for calculating red shift \( z \) is given by \( z = \frac{\Delta \lambda}{\lambda_0} = \frac{v}{c} \), where \( \Delta \lambda \) is the change in wavelength, \( \lambda_0 \) is the original wavelength, \( v \) is the velocity of recession, and \( c \) is the speed of light.
Review Questions
What causes red shift in terms of wave mechanics?
How does red shift support our understanding of an expanding universe?
Write down and explain the formula used to calculate red shift.
Related terms
Doppler Effect: The change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.
Blue Shift: A decrease in wavelength (increase in frequency) observed when a light-emitting object moves closer to an observer.
Wavelength: The distance between consecutive crests or troughs in a wave.