Redshift Explained: How Galaxies Reveal Their Motion

Redshift happens when light stretches to longer, redder wavelengths as objects move away.
It’s the cosmic equivalent of a Doppler effect, but with light instead of sound.
Edwin Hubble used redshift to show galaxies are receding, proving universal expansion.
The greater the redshift, the faster and farther away a galaxy is.
Redshift is measured by comparing known atomic lines to their shifted positions in starlight.
Cosmological redshift arises from space itself expanding, not galaxies moving through space.
Astronomers classify redshift into three types: Doppler, gravitational, and cosmological.
Quasars, some of the brightest objects in the universe, display extreme redshifts.
Redshift surveys help map the large-scale structure of the cosmos.
Without redshift, we wouldn’t know the universe is growing, evolving, and billions of years old.