Redshift: Measuring the Universe’s Expansion

Redshift occurs when light from an object is stretched to longer, redder wavelengths.
It happens when galaxies move away from us as the universe expands.
The greater the redshift, the faster the object is receding.
Astronomer Vesto Melvin Slipher first measured galaxy redshifts in the early 1900s.
Edwin Hubble linked redshift to distance, leading to Hubble’s Law.
Redshift is a key tool for measuring the scale and age of the universe.
It reveals that the universe has been expanding since the Big Bang.
Extremely distant galaxies show high redshifts, letting us see them as they were billions of years ago.
There are three kinds: cosmological redshift, Doppler redshift, and gravitational redshift.
Redshift measurements underpin modern cosmology, from galaxy surveys to dark energy studies.