redshift

Redshift is the phenomenon where light from an object moving away from us stretches out, shifting toward the red end of the visible spectrum. In astronomy, this indicates that galaxies are receding due to the universe's expansion. Think of it like a siren's pitch dropping as it moves away; similarly, light waves extend, making distant objects appear redder. Redshift helps scientists measure how fast celestial objects are moving away and provides evidence for the universe's expansion, aiding in our understanding of cosmic history and structure.