Hi all, I'm currently working on a uni essay, the subject of which is how the properties of light are (and have been) used to discover and observe objects in astronomy. So far I'm looking into how the value of c is used, how doppler shift is used to determine velocities, how looking at the different parts of the EM spectrum can give a different view of the cosmos and something else that emcompasses spectroscopy/black body curves. If anyone can suggest additional relevant topics or websites that would be greatly appreciated or if you just want to discuss the above subjects that's also great. Also, I read that the faster a galaxy rotates the greater its apparent brightness. Can anyone confirm this, if so would you be able to explain how it works or recommend a good site? Thanks.