Timz

Hi Timz--- I am sorry for the arrogance you perceived, but it is not arrogance, this is a new site, and we are trying to work out dynamically what the scope of the discussion should be. Your question can be understood relatively simply by those that know relativity, but the historical aspects require some digging into the original literature (but this digging is already done in many places), so it is not clear whether your question was appropriate. This is not snobbery, but an attempt to keep the site from being filled up with stuff that would distract a professional, stuff which can be best answered elsewhere.

In this case, I gave you an answer which should be satisfying, and I hope you can chip in and say whether the setup of the site is problematic for a student, whether it is too 'arrogant'. Really, it is not a judgement on you, your question is excellent, it is just that the answer is very well known.