I thought I’d step away from talking about industry-related topics to discuss time travel. We’ve seen in the movies two kinds. In the first (I’ll call it Type A), a person exists at all times. That means if you travel to the future, you will find an older version of yourself, assuming you’re still alive.
In the other (Type B), you can only exist now. So if you travel to the future, you won’t find an older version of yourself, since you had stopped existing when you left.
The movie “Back to the Future” breaks this boundary early in the movie, when Dr. Brown’s dog Einstein is sent one minute into the future. Einstein should have arrived to see a version of himself that’s one minute older (Type A), but instead he’s the only Einstein (Type B). If you recall, when Marty goes into the future in the sequel, he sees an older version of himself (Type A). Thus, both kinds of time travel are shown in the trilogy (there’s also a major problem in “Back to the Future II,” but I won’t get into that).
Movies like “Bill and Ted’s Excellent Adventure” and “Looper” are all Type A. “Hot Tub Time Machine” is almost like Type B, since the main characters don’t see their young selves in the ’80s, since they are their young selves.
In my opinion, if time travel were possible, then we would have Type A. It’s because to travel backward or forward, you would have to hope that everything in all times exists, otherwise you would have nowhere–I mean, no time–to travel.
One thing I do believe in is time dilation, which Albert Einstein used to explain the difference in elapsed time during two events. In simplest terms, a person moving (preferably toward the speed of light) will have aged less than a person who is stationary.
Of course, there are other debate topics of time travel. One is the grandfather paradox, in which a time traveler kills his grandfather before he has kids of his own, and thus the time traveler ceases to exist. Assuming history is immutable, then it may be impossible for the time traveler to actually kill his grandfather, since the latter had lived according to history.
By the way, I didn’t see “Back to the Future” in the theaters when it first came out in 1985, but I did when it returned in October of 2010 for its 25th anniversary. Boy, that was a fun experience–just like going back in time.