Question

Why is the Doppler effect important for astronomy?

Answer 1

Doppler effect is that the light emitted from a source is shifted in wave-length by the motion of the light source. Hubble's linear correlation is attributed to this effect., .

Explanation:

Hubble's linear correlation:
Recession velocity = `H_o` X Distance.
`H_o` = 67.8 km/sec/megaparsec, nearly.