Figure is a graph of intensity versus wavelength for light reaching Earth from galaxy NGC 7319, which is about 3 × 10⁸ light-years away. The most intense light is emitted by the oxygen in NGC 7319. In a laboratory that emission is at wavelength λ = 513 nm, but in the light from NGC 7319 it has been shifted to 525 nm due to the Doppler effect (all the emissions from NGC 7319 have been shifted).

(a) What is the radial speed of NGC 7319 relative to Earth?

(b) Is the relative motion toward or away from our planet?

Transcribed Image Text:

800 -1 △ +12 nm | NGC7319 Laboratory wavelength 400 200 400 450 500 550 600 650 700 750 Wavelength (nm)