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How to construct a light saber?

Sascha Vogel unmasks Hollywood movie physics



In his talk at the GSI lecture series "Wissenschaft für Alle" on 19 September Dr. Sascha Vogel takes a look at Hollywood movies. With simple calculations he shows why physicists shake their heads when watching Armaggedon, James Bond and others. 

In the Star Wars-movie Darth Vader destroys the planet Alderaan. "We can deduct from the shock wave how much force the explosion had", says Vogel. "To destroy the whole planet you would need the amount of energy emitted by the sun in two years."

Don't be afraid of scientific terms

Sascha Vogel is a theoretician. On several science slams he already proved that physics can be very entertaining. But he doesn't only show amusing clips. Recurringly he blends in scientific terms as conservation of momentum, law of inertia or quantum chromo dynamics – including the formulas.

Rank 1: The Core

Vogel also presents his top three Hollywood movies with bad physics. Rank 3: Armageddon. The two halfs of the exploded comets passing earth would cause terrible tsunamis because of their gravity. Rank 2: James Bond. And Rank 1: action movie The Core. "The worst two hours of my life as a physicist", he claims. Highlights of physics mistakes are a wrong prime number and Earth rotating in the wrong direction during the credits.

Light saber – an energy problem

The construction of a light saber is a bit more complicated. For them to intersect like real swords you'd need an extreme light intensitiy. Otherwise they would just pass through each other like the beams of two flashlights. "Only with very high energies one could produce light sources that interact with each other", Vogel explains. "It requires intensities of 1033 Watt per square centimeter. This excites the vacuum and matter-antimatter-pairs would be created facilitating the possibility for an interaction. As a comparison: The sunshine only has an intensity of 8000 Watt per square centimeter."

Spiderman not just sci-fi

A surprise waits at the end of Vogels talk. Not all seemingly absurd science fiction scenes are physically impossible. Spiderman's silk could hold a fall from 100 meter height. "Spider silk is one of the toughest materials on Earth."

Spiderman - The silk withstands!
Foto: Huhu at de.wikipedia