Monday, 18 April 2011

Angels and Demons

Some people get really upset when movies have bad science in them. Despite being a sciencey type myself, I feel the opposite. The more fantastic the concept, the more entertaining I find it. I suppose it's because I take it as a sort of science slapstick comedy rather than the intended movie genre.

Take the movie 2012, for example. Unfortunately it hasn't been ripped to shreds by Insultingly Stupid Movie Physics. Who doesn't want to see a giant tsunami crashing over the Himalayas?

Last night I watched Angels and Demons. It was on TV and I wanted to unwind after a busy day. I'm not a fan of Dan Brown at all. I haven't read his books, but the murder mystery style of the movies is kind of entertaining. For those who haven't seen it, the crux of the movie is that the Illuminati are threatening to destroy the Vatican with some antimatter stolen from CERN.

Now, this antimatter is in a battery powered hand held vial about the size of a water bottle. We are told that the antimatter must be held in a magnetic field or it will just annihilate matter in the container walls. It is true that matter and antimatter annihilate when they come in contact, releasing high energy photons. If you had a milligram, it would be enough for an explosion of the equivalent of 50 tons of TNT. This could potentially be done at CERN with its present capabilities, but it would take 300 billion years to accumulate that much.

There is a nice article at the CERN Courier talking about what it takes to trap antimatter. It takes some very strong magnetic fields, which requires some pretty high currents (since electromagnets are required). So clearly, the hand held antimatter container is highly improbable.

However, this is not what bothered me. What bothers me is that the physicist in the movie says that with their breakthrough in trapping antimatter on a large scale (1 mg), they hope to use it as an energy source to power cities, and not as a weapon. Hold on a second. Their container has a magnetic trap to hold the antimatter. The current for the trap is provided by a battery that lasts up to 24 hours. The magnetic field required to hold antimatter is on the order of several Tesla, generated by superconducting electromagnets. Even if the antimatter is ultracold (like a BEC), you would still need a fairly hefty field. This requires a very high current! Hundreds of amps! Generated by a battery!!

If you have a battery powered device that can trap antimatter, then you probably don't need antimatter as an energy source.

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