redshift
UK: ˈrɛdʃɪft | US: ˈrɛdʃɪft
n. (Astronomy) The displacement of spectral lines toward longer wavelengths in the light from distant galaxies, indicating the object's motion away from the observer (Doppler effect).
n. (Physics) A similar phenomenon in other wave-based observations due to relative motion or gravitational effects.
Coined in the early 20th century, "redshift" combines "red" (the longest visible wavelength) and "shift" (movement), describing how light from receding objects stretches toward the red end of the spectrum. The term reflects Edwin Hubble's discovery of the expanding universe, where galaxies' light spectra systematically shift redward as they move away. The morphemes directly map to the physical phenomenon: color change ("red") + positional change ("shift").
Astronomers measure redshift to calculate the distance of galaxies.
The quasar's high redshift suggests it is moving away at relativistic speeds.
Gravitational redshift occurs near black holes due to intense gravity.
Hubble's law correlates redshift with cosmic expansion.
Without redshift, we might not have discovered the Big Bang theory.