
The Universe's Stretch: The Redshift
Redshift is a phenomenon that occurs when light from stars and galaxies shifts to longer wavelengths, toward the red end of the spectrum or beyond. For distant galaxies, the main cause is the expansion of the universe, which stretches the light waves as they travel to us. Movement through space can also cause redshift. Using a model of cosmic expansion, scientists can use cosmological redshift to estimate distances to faraway galaxies and learn about the universe.
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