Students calculate how to build Star Trek photon torpedoes

Physics students at the University of Leicester have boldly gone where no student has gone before – by calculating one way to potentially build photon torpedoes seen in the Star Trek universe.

Announced to coincide with the release of Star Trek: Beyond, which opens in UK and US cinemas on 22 July, the students’ findings suggest that in order to function correctly, a photon torpedo could be made out of heavy metals such as lead or uranium, as metals with fewer protons would not have the necessary cascade length.

The students presented their findings in a short article for the Journal of Physics Special Topics, a peer-reviewed student journal run by the University’s Department of Physics and Astronomy. The student-run journal is designed to give students practical experience of writing, editing, publishing and reviewing scientific papers.

In the hit 60s television show photon torpedoes are stockpiled on the Starship Enterprise and were used to fight off enemies such as the Klingons and the Borg.

They also featured prominently as the resting place of Benedict Cumberbatch’s Khan in the 2013 film Star Trek: Into Darkness. Khan had been cryogenically frozen within the torpedo, before waking to assume the role of the film’s antagonist.

Merging their passion for physics and Star Trek, the students examined the materials which could plausibly be used to build one of the deadly weapons.

Through detailed analysis of the show, they found that one plausible way for the torpedoes to work is by enacting an ‘Annihilation reaction’ in its core. This reaction involves anti-matter and matter colliding with one another to cause a chain reaction, resulting in an explosion.

In the study, they predicted that if the torpedo initiator is energetic enough, it would generate an electromagnetic cascade - where incoming highly energetic particles start to produce matter and anti-matter pairs (electrons and positrons) which are used to fuel the photon torpedoes when interacting with a metal such as iron, uranium or lead.

The generated pairs are highly energetic and produce another anti-matter/matter pair while traveling through the medium. This process goes on until the number of electrons and positrons reaches 10 to the power 30, which constitutes the total rest mass of 3 kilograms of positron and electron pairs.

When the pairs reach this number they tend to collide - or 'annihilate' - into each other to produce photons which result in the explosions seen in Star Trek.

By examining the cascade lengths of various metals, they concluded that, if someone wished to build a photon torpedo at home, one way could be to make it out of a metal with a greater proton number than iron, as any metal that contains fewer protons would not have the subsequent cascade length for a reaction to take place.

Such metals, they suggest, are lead and uranium with proton numbers of 82 and 92 respectively, therefore beating the required threshold of iron’s 26 protons.

The physics students suggested that, in the future, extreme high energy free electron lasers, or controlled Gamma ray bursts could be used as a highly energetic initiator to trigger the cascade.

These findings come in the wake of the third instalment in the rebooted Star Trek film franchise, Star Trek: Beyond. The film is to be headed by Fast and Furious director Justin Lin, who stepped into the shoes of director J.J. Abrams after he left the franchise to helm last year’s critically acclaimed Star Wars: The Force Awakens.

Star Trek: Beyond is released in theatres in the UK and US on 22 July.     

  • Read a feature about how 'zany' science projects help students learn how to communicate research findings here:
  • The student paper ‘Electromagnetically Cascading Photon Torpedoes’ is available here:

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