Thursday, August 13, 2009

The secret lives of magnetic fields

Snap, crackle, pop. The world is alive with invisible magnetic field lines. Take a length of wire with a current running through it; it generates a magnetic field that curls around the wire, but we can't see it.

Magnetic Movie from Semiconductor on Vimeo.



Video artists Ruth Jarman and Joe Gerhardt, who work under the moniker Semiconductor, shot footage of empty lab space at UC Berkeley's Space Science Laboratory. Then they brought the inanimate objects to life, painting in the vivacious spaghetti of magnetic field lines coming off the unassuming electronics. The pair, who hail from London, spent four months "researching and experimenting" at the northern California lab, which tackles a smorgasbord of space physics topics, from the search for extra terrestrial intelligence to solar flares. One might say that the scientists were "researching and experimenting," and that the artists were watching. Or one might say that Semiconductor's appropriation of raw satellite data of coronal mass ejections was a form of data processing, and that when they videotaped the lab's scientists trying to answer one very tough question, they were trying to prod the borders of science's domain.

I should warn that Semiconductor's magnetic field lines, while certainly beautiful (especially with all the added space-noises!) are not what the field lines of these objects actually look like. (The scene with the wires is the biggest give-away.) But I think the artists skillfully evoke this invisible force, even if they're not portraying it in a way true to nature. Think impressionism rather than realism.

I found the inaccuracy a little disappointing until I found SSL's website for IMPACT, a suite of instruments that collect data about solar wind electrons and the sun's fluctuating magnetic field. IMPACT is part of STEREO, two space craft, one in front of the earth and one behind, that monitor the sun's storms. If you watch the videos on the STEREO site (the introduction is a good one), it seems like Semiconductor were drawing their inspiration from the "hairball" of magnetic field lines on the sun, and the violence of coronal mass ejections, hot balls of plasma the sun fires toward earth on occasion. Another fun resource are these animated models on the IMPACT page, which raises the question again - Who are the artists here and who are the scientists?




Semiconductor's animations are inspired by some really interesting science, but wouldn't it be cool to see what magnetic field lines actually look like? Check out Falstad.com, the Disneyland of physics computer applets, which has a great little widget that allows you to see the magnetic fields and vector lines of some common configurations like a current-carrying wire, a loop of current, or an electromagnet. You can move your wire around, change the strength of the field, or sprinkle the air with tiny current carrying loops and see what happens. Just make sure to read the directions!





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