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Friday, July 15, 2011

Magneto Gets an F

Last night I watched X-Men: First Class, and enjoyed it very much; it was far better than I remember the earlier movies being.  However, there's something that has always bothered me about the X-Men franchise: it seems Magneto, the mutant who can create powerful magnetic fields at will, never took physics.  There's much more he could be doing with his power, aside from tossing metal things around.

Before I get into that, I'd like to figure out exactly how powerful his magnetic fields are.  During one scene, he lifts a submarine out of the water and into the air:
A little research suggests that, although this is not a real submarine model, the Type XXI is a good approximation.  Using the length of the sub as a scale, we can estimate that the center of the sub (where we'll assume its center of mass is) is about 21 meters above the bottom of the picture.  The energy required to lift something to a specific height is given by
where m is the mass of the object, g is the acceleration due to gravity, and h is the height to which it is raised.  We can get an underestimate of this energy by assuming the submarine was on the surface of the water when Magneto started lifting it.  Plugging in the values we have, it would take 3.3 x 10^8 Joules.  I estimate it takes him about 20 seconds to get it there, giving a power output of 1.7 x 10^7 Watts.  [Update: I realized that, if that energy is coming from Magneto himself, he must be eating at least 80,000 Calories per day.]

With that in hand, we can turn to other uses of Magneto's power.  Maxwell's Equations tell us that changing magnetic fields induce electric fields, the simplest application of that being to create currents in conductors.  However, if he can create 'accelerating' magnetic fields (ones with non-zero second derivative), he can shoot lasers.  Light is made up of oscillating electric and magnetic fields, and since each induces the other, you only need one to get things started.  If he could manage to produce gamma rays (a dangerously high-energy variety of photons), according to our power output calculated above, he'd be putting out 8.6 x 10^20 photons/second.  That's about on the order of how many photons a lightbulb produces, but we're talking about a lightbulb putting out lethal radiation.

I suppose it wouldn't make for a very interesting story if Magneto simply gave everyone on Earth radiation poisoning, so maybe the writers are justified in ignoring this possibility.  It still would have been better than this possibility.

4 comments:

  1. Next, use your physics powers to explain how Archangel (the guy whose mutant power is "having wings") is even *less* useful than he appears.

    Seriously, though, can you give a more detailed explanation of magnetic fields with a non-zero second derivative? Can we generate them in a lab? Do they occur naturally? If I have an electromagnet and I vary the input power, would that produce photons? And are the photons being produced, or just redirected?

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  2. http://www.youtube.com/watch?feature=player_embedded&v=PCnDsR5kLOQ

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  3. Orion this is brilliantly entertaining and informative. You should add Like, +1, and Tweet buttons to your site so I can share this with others who will appreciate it as much as I do!

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  4. Thanks, Steve. I considered adding that sort of thing, but I'm reluctant to clutter the page with little badges for every site.

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