Redshift and blueshift are used by astronomers to work out how far an object is from Earth. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

A Doppler shift is defined as a change of frequency of light or sound when an object is moving toward or away from an observer. Edwin Hubble observed in 1929 that galaxies appear on average to be ...

When astronomers stare into the deep universe or at the spectra of a distant star subtly hiding an exoplanet, they need to account for its movement. That relies on two phenomena — redshift and ...