The Philadelphia Experiment is a 1984 American science fiction film. It is directed by Stewart Raffill, stars Michael Paré, Bobby Di Cicco, Kene Holliday and Nancy Allen and is based on the urban legend of the Philadelphia Experiment. In 1943, United States Navy sailors David Herdeg (Paré) and Jim Parker (Di Cicco) are thrown forward in time to the year 1984 when a scientific experiment being performed aboard the USS Eldridge suffers a catastrophe. The film follows the two men as they attempt to survive the future and race against time to put an end to the experiment that now threatens the fate of the entire world.

In 1943, United States Navy sailors David Herdeg and Jim Parker serve aboard destroyer escort USS Eldridge, docked in Philadelphia. Doctor James Longstreet and his team conduct an experiment to render the ship invisible to radar, but a malfunction causes the ship to disappear. David and Jim's attempts to stop the experiment fail and they jump overboard to escape.

They land during the night in a small town, which also disappears, leaving them marooned in a desert. Startled by the appearance of an unfamiliar aircraft (a helicopter), they flee and Jim is nearly electrocuted by an electric fence. Eventually, they find their way to a roadside diner. An energy discharge from Jim destroys two arcade games, forcing an altercation with the owner. Fleeing to the parking lot, they take a woman named Allison hostage and force her to drive them away. Confused by their surroundings, they are shocked when Allison tells them that the year is 1984. They are tracked and apprehended by the police. Jim, who is suffering increasingly severe seizures, is hospitalized before disappearing from his hospital bed in a flash of light. David and Allison then evade military police, who have arrived to take David into custody.

Learning that they are near Jim's birthplace, Santa Paula California, David decides to try to find his family. Jim's wife Pamela, who is now a senior citizen, immediately recognizes David from 1943. She says that the Eldridge had reappeared minutes after disappearing. Jim had also returned and had been chastised and hospitalized after telling the truth about temporarily visiting 1984. David finds that he himself never returned. David sees an elderly Jim outside a window but Jim refuses to speak with him. As David and Allison leave, they see military police approaching and a high speed chase through Jim's ranch ensues. The two manage to elude them when the pursuing vehicle crashes and burns. From the burning wreck, David salvages documents mentioning Longstreet. Recognizing that Longstreet had been involved with the Philadelphia experiment in 1943, David decides to find him. As they spend time together, David and Allison fall in love.

In 1984, Longstreet has attempted to use the same technologies that were used in the Eldridge experiment to create a shield as protection from an ICBM attack. When the equipment was tested, the shielded town disappeared into "hyperspace". The scientists are unable to shut down the experiment, which has created a vortex that is drawing matter into it and causes extremely unstable and severe weather. Longstreet predicts that the vortex will continue to expand until the entire world is consumed. The scientists send a probe into the vortex and discover the Eldridge inside. They theorize that the two experiments have linked together with the generators on the Eldridge powering the vortex.

David captures an assistant at Longstreet's home and forces the man to take them onto the base. Longstreet explains the situation to David and tells him that, according to surviving sailors from the Eldridge, the ship returned to Philadelphia in 1943 after David shut down the generator. Longstreet says that David must go through the vortex to the Eldridge and terminate the experiment or the vortex will destroy the Earth.

David is outfitted with a protective suit to allow him to shut down the experiment and catapulted into the vortex. He lands on the deck of the Eldridge, where he finds crew members badly injured. He hurries to the generator room and smashes arrays of vacuum tubes using a firefighting axe. The generator shuts down and David looks for Jim. Assured that Jim is fine, David jumps over the side of the ship and disappears. Back in 1943, Longstreet and others watch the Eldridge reappear in Philadelphia, revealing crew members with severe burns, while others have been fused alive into the ship's hull.

In 1984, the missing town reappears as Allison and David are reunited.

• Michael Paré as David Herdeg
• Nancy Allen as Allison Hayes
• Eric Christmas as Dr. Jim Longstreet
  • Miles McNamara as Young Jim Longstreet
• Bobby Di Cicco as Jim Parker
  • Ralph Manza as Older Jim Parker
• Louise Latham as Pamela
  • Debra Troyer as Young Pamela
• Stephen Tobolowsky as Barney
• Kene Holliday as Major Clark
• Joe Dorsey as Sheriff Bates
• Michael Currie as Magnussen
• Gary Brockette as Adjutant / Andrews
• James Edgcomb as Officer Boyer
• Glenn Morshower as Mechanic
• Vaughn Armstrong as Cowboy

• A sequel called Philadelphia Experiment II, featuring a different cast and crew, was released in 1993.
• A made-for-television reconception of the original film was released in 2012 on SyFy. Michael Paré also appears in this version, but in a different role.