Question

An observer on earth observes that wave length of spectral line in spectrum of a milky way shifts towards red end of spectrum. According to the observer, the milky-way is

• A. approaching the earth
• B. receding away from the earth
• C. stationary
• D. rotating about its own axis

Answer 1

Answer: (B)

receding away from the earth

When an object moves away from us, its light waves are stretched into lower frequencies or longer wavelengths, and we say that the light is redshifted.

It also explain the expanding nature of universe. Shifting towards red end means wavelength is increasing. There, milkyway is receding away from earth.