Astronomy & Space
Advanced

Redshift

Fractional wavelength shift of light.

Formula

z=λobs−λemitλemitz = \frac{\lambda_{obs} - \lambda_{emit}}{\lambda_{emit}}

Variables

\lambda_{obs}Observed
\lambda_{emit}Emitted

Example

A line shifted from 500 nm to 505 nm gives z = 5/500 = 0.01.

Did You Know?

The light of galaxies is stretched toward red as space itself expands — cosmic evidence for the Big Bang.

redshiftcosmologylight