Wavelength physics question

Question

Imagine the hydrogen atoms in one of Hubble's distant stars emitting a photon of light at a wavelength of 410.17 nm. If that particular proton were headed directly toward Earth, how much closer to us would that photon be after one second? 

Answer 1

 

Hello Rachel

Speed = distance / time

 

3*10 ⁸ = distance /1

 

distance moved by the photon = 3*10 ⁸ m

( I am reading proton as photon in the second line of the question )

The wave length may change due to Doppler effect , depending upon the relative motion between the earth and the star