Stephen Hawking, one of the most brilliant theoretical physicists in history, wrote " A Brief History of Time" for help in understand fundamental questions of physics. Could help you out.
I'm sure it will make your paper look "good" :-P
And you may include Pythagoras and Einstein
The theorem, which is applicable to right angled triangles in flat Cartesian (Newtonian) space
c^2 = a^2 + b^2.
Then you could jump right ahead to Einstein's theory of Relatvity which states that mass lengt and time aren't constant approachin to the speed of light L_f = (1 - v^2/c^2)^-1/2.
But first you must start with what time is, go through the History of how we developed our understandng of it and then go with what we might understand in th future. Tormod gave you a great piece of info there - " the path" for all the best site abut time travel and time machines
Time travel is not possible
here's is something from me (that I found) which could make your paper even more interesting by having two sides :-)
Don't forget to include Einstein's space-time theories.
Eva
The Oracle of the Past
P.S. Excuse my mistakes but I'm not even going to preview now ...