We observe an absorption line of Oxygen at 504 nm in Star A and at 508 nm in Star B. We know in the lab
this line has a wavelength of 500 nm. Which statement correctly describes the motions of Star A and B?
Group of answer choices
Star B is moving towards us half as fast as Star A
Star B is moving away from us half as fast as Star A
Star B shares the same motion as Star A
Star B is moving towards us twice as fast as Star A
Star B is moving away from us twice as fast as Star A
1 answer
Based on the observed wavelengths of the absorption line, we can conclude that Star B is moving away from us twice as fast as Star A.