Time travel is a fascinating subject considering its impossibility due to the laws of physics (punks). While we are "all" time travelers in a sense, moving forward at a rate of 1:1 just doesn't have the same excitement as mixing it up and jumping through time like its a water park slide. I am quite a movie fanatic and a good portion of my collection deal with time travel in one way or the other. Upon gazing across the DVD's I began to notice there were patterns between these different takes on impossibility. While new methods of time travel storytelling are always popping up, the classics fall into a few categories worth discussing. Note: Much of the discussion below involves plot spoilers.

Alternate Futures - Changing Time Tracks

Back to the Future II The Back to the future Trilogy is a great Sci-Fi staple of the changing tracks view on time travel. This theory is best explained by Doctor Emmet Brown. On an old chalk board he draws out how when they took the DeLorean back to 1985, because of Biff's tampering with the timeline they were now in an alternate timeline. In this timeline Biff was powerful and wealthy and married to Marty's mother!

Star Trek This method of time travel is also used in the 2009 Star Trek film. The entire plot takes place in an alternate Star Trek universe where many historical points are different from the "Prime" universe we have grown up with on television with William Shatner.

Predestination Loop - You Just Didn't Know It

Twelve Monkeys I enjoy the recursive nature within the film Twelve Monkeys. James Cole (Bruce Willis) travels back in time to before a worldwide epidemic wipes out most of the population. He is attempting to discover what caused this massive plague. Speckled throughout the film are flashback sequences of a young James recalling a traumatic day at the airport. The man causing all of the ruckus turns out to be the elder James while his is back in time. This predestination loop theory revolves around the audience believing the story is viewed from the main characters point in time. The audience is continuously transplanted between our normal time perspective of the present to James's view from the future. This is an important concept in all time travel movies as you are not only setting up which characters perspective we are using, but what time we view the unfolding events from.

The Time Machine The 2002 remake also exists within a predestination loop. No matter how many times Alexander travels back and tries to save the life of his beloved he cannot. It is predestined. As stated by the Über-Morlock, "You built your time machine because of Emma's death. If she had lived, it would never have existed. So how could you use your machine to go back in time and save her? You are the inescapable result of your tragedy, just as I am the inescapable result of you. You have your answer. Now go."

The Terminator This is another great example of a predestination loop. Kyle Reese is predestined to conceive John Conner with Sarah Conner. Yet John Conner is the one who sends his "father" back in time. This paradox occurs due to the audience's shift of time perspective. The film begins with the "future" where the machines have taken over and the resistance is fighting it's last fight. But we inherently pull our perspective back to our own time and then view the paradox of John Conner's birth. Had we remained in the future no paradox would appear to exist.

Donnie Darko It took a couple of viewings to have this predestination paradox make sense. This is mostly due to the fact that Donnie Darko is not just a time travel movie, but deals with many other deep issues of consciousness, time, predetermination, and physics. This website helps sort through the deep plot.

Parallel Universes - Same Time, New Duds

Star Trek: The Next Generation The seventh season episode "Parallels" exhibits an interesting time travel style. Lt. Worf jumps between parallel universes, he does not move forward or backward in time. It remains Stardate 47391.2 no matter which universe he is occupying. The multiverse theory dictates that every action and choice we make results in an infinite number of universes where we make "all" choices. Worf moved between a few of these universes which were similar to his "prime" universe but different in key ways. Different species were at war, uniforms and ranks were different, and in one sliver of time the Borg had destroyed the federation.

Back and Forth - Standard Time Travel

The Time Machine In the 1960 version of The Time Machine George travels in his machine to the far flung future of the year 802,701. He is simply interested in viewing the progress of mankind, not altering the past. His time machine is more of an accelerator, propelling him into the distant future.

In Sync - Its in Real Time

Frequency Frequency is unique among time travel films in that it deals with a direct radio link between 1999 and 1969. This connection happens in "realtime", at least a sense of realtime as perceived by the audience. This creates the dramatic conclusion where the heated struggle in 1969 changes the timeline and floods new memories and altered physical appearances into 1999.

No Effect - We Don't Care

Bill and Ted's Excellent Adventure Add one part Richard Carlin, one 80's phone booth, and the greatest historical personalties from Napoleon to So-Crates! This film takes a loose look on the laws that might govern time travel. So be most excellent to each other and watch it.

Doctor Who To quote the Doctor, "People assume that time is a strict progression of cause to effect, but actually, from a non-linear, non-subjective viewpoint, it's more like a big ball of wibbly-wobbly... timey-wimey... stuff." I find it best to view Doctor Who as a fantasy. The Doctor is a wizard with his sonic screwdriver to "magically" open doors and repair things. Time is all wibbly-wobbly!

Here is an awesome infographic I found listing several time travel films.

Time for Time Travel Talk