The Philadelphia Experiment

The Philadelphia Experiment is a Science Fiction film published in 1984 about Time Travel.

Two sailors from 1943, David Herdeg and Jim Parker, become Fish Out of Temporal Water when the US Navy destroyer they are stationed on vanishes as an unforeseen side-effect of an experiment in creating an electromagnetic Invisibility Cloak, and they find themselves in 1984. While they deal with the culture shock, Parker gets sick and vanishes, apparently sucked back in time. Herdeg, searching for an explanation for what happened to him, winds up at a military installation where it is revealed that a second cloaking experiment is underway, this time involving an entire city. It, too, vanished, and now there's a huge vortex in the sky that is sucking everything into it and growing larger.

It turns out that the interaction of the two experiments, one in 1943, the other in 1984, has created a time warp that captured both the destroyer and the city and threatens The End of the World As We Know It. Herdeg is given an experimental suit to protect himself from the effects of the vortex, and allows himself to be sucked back in in an attempt to shut down the destroyer's cloaking field.

The movie is Inspired By, and takes its name from, a supposed real invisibility experiment conducted during WWII which resulted in the same "side effects" as depicted in the movie. Today it's regarded as being little more than the stuff of overactive, discredited conspiracy theories.

A sequel, The Philadephia Experiment II, was released in 1993. Herdeg wakes up one morning to discover that Germany has retroactively conquered the United States, apparently having won World War Two using a mysterious super-bomber. It turns out that yet another teleportation experiment resulted in the transportation of a nuclear-armed F-117 Nighthawk stealth fighter to 1943, and he must return to the past to stop it from being used by the Nazis. It features none of the original cast.

Tropes present in The Philadelphia Experiment:

 * Did Not Get the Girl: Subverted. Herdeg is forced to leave his Love Interest, Allison, behind when he enters the time vortex. It's strongly hinted that he'd eventually have been sucked back just like Parker anyway.
 * Disney Death
 * Fish Out of Temporal Water
 * Foreshadowing: Parker's wife in 1984 tells Herdeg that, "You never came back."
 * Gone Horribly Wrong
 * Invisibility Cloak: For a navy destroyer and an entire midwestern town. It's actually intended just to hide them from radar, but clearly doesn't work exactly as intended.
 * Mass Teleportation
 * Our Time Travel Is Different: The wormhole version.
 * The Slow Path: Poor Parker has to live out 41 years of ridicule while his buddy Herzeg gets to gallivant around in 1984. No wonder he's bitter.
 * Temporal Paradox: If the time vortex is stopped back in 1943, then how does it start in 1984 and cause the events of the movie? This is, perhaps mercifully, left unanswered.
 * Time Crash
 * Time Travel
 * Walking Techbane: Of the accidental type; absorbing the electrical shock from the destroyer's generator causes Parker (and later Herdeg) to occasionally short out nearby electronics and attract thunderstorms.
 * What Year Is This: Parker and Herdeg figure out that they're in the future from copious clues, but have to ask for the precise date.
 * You Have to Believe Me: Parker's "insane" story of traveling in time got him put in a mental institution after he was sucked back. When Herdeg looks him up in 1984, he's a bitter old man.

Tropes present in The Philadelphia Experiment II:

 * For Want of a Nail: A rather big nail, but still.
 * Giving Radio to The Romans: Albeit by accident -- a stealth aircraft armed with nuclear bombs is transported back in time to Nazi Germany, where it's used to attack several cities in the eastern United States.
 * Godwins Law of Time Travel: The point of the film.
 * Gone Horribly Wrong: You'd think that scientists in this world would have figured out by now not to try to teleport things or make them invisible.
 * The Other Darrin: None of the original cast returned for this film, so different actors played the two continuity characters.
 * Ripple Effect Proof Memory: Somehow the altered modern timeline knows about what went wrong in the unaltered one.
 * Set Right What Once Went Wrong: A variation in that Herdeg has to fix the past to stop the future from screwing with the past.
 * Stable Time Loop: Inverted; see below.
 * Stupid Jetpack Hitler: Thanks to Time Travel.
 * Temporal Paradox: In this case, setting right what once went wrong destabilizes the Stable Time Loop and erases the entire incident from ever having happened.
 * Time Travel