-It's impossible to change the present because the past has already happened. You see, the past is written in stone because it has already happened by the time you get to the present. Like, if you travel back in time and kill the president, it won't affect the present because it's already happened. It doesn't matter if you do anything in the past, you've already traveled through time and done what you did, that's how the present works. It's like a string, you're at the 4 foot mark, even if you travel back to the 1 foot mark, you can't change the four foot part, because the 1 foot mark has already occurred.
-Shepard is 31 in ME2, Tali's 24, Miranda's in her mid-30's.
-Master Chief didn't die at the end of Halo 3, he froze himself and probably come back to fight in the future.
-The New Star Trek movie doesn't have to follow any previous cannon because it's actually set in an alternate universe, caused by Spock traveling back in time.
-I would fuck Tali, Ahsoka, and Neytiri(if she was like 5-10) at the drop of a hat.
There! Does that prove my nerdiness?