What is the difference between a redshift and a blueshift?

Redshift and blueshift are two important concepts in physics and astronomy. They are related to the Doppler effect, which is the change in the frequency or wavelength of a wave due to the relative motion between the source of the wave and the observer.

Redshift refers to the increase in the wavelength of a wave when the source is moving away from the observer. This means that the frequency of the wave decreases as well. Redshift is commonly observed in astronomy, where it is used to measure the distance and speed of celestial objects. The greater the redshift, the farther and faster the object is moving away from us.

Blueshift, on the other hand, refers to the decrease in the wavelength of a wave when the source is moving towards the observer. This means that the frequency of the wave increases. Blueshift is also observed in astronomy, but it is less common than redshift.