Ok guys, Helping my girlfriend out once again. She(if you haven't seen this before) is in Physics 101....yet, I(have taken all engineering courses) can't figure these out. Their book is absolutely terrible!! Please give an answer that I can understand(as I like to learn too).....and one also that I can explain to her, so she will understand. I appreciate the help!!!
If an astronomer examines the emission spectrum from luminous hydrogen gas that is moving away from he Earth at a high speed and compares it to a spectrum of hydrogen seen in a laboratory on Earth, what would be different about the frequencies of aspectral lines from the two sources?
I don't have any clue as to the answer. Thanks again guys!