If you use Wikipedia, try to follow the associated links to the original source material, and quote THAT. Wikipedia is valuable but it generally isn't considered a quotable original source.
Also, make sure that any useful stuff that you get here is either rewritten in your own words, or that the author here (and the site itself) is cited. You wouldn't want to get in trouble because you used text that was written by someone else.
I think Siskel and Ebert have done some retrospectives on Star Wars that could be useful, and I think they would be considered a quotable editorial source.
There is a book called "The Science of Star Wars" by Jeanne Cavelos (I didn't find it to be as interesting as it sounds), that is fairly scholarly and you might find it useful for any sections of your paper that relate to actual science.