Monday, 04 June 2007

For Shame, Science, For Shame Deep in the wee hours of this morning, I caught "Killer Waves" on the Discovery Science Channel. Despite the tired narrative arc of Discovery Channel shows—unique situation, partial explanation; complication, partial retraction; similarly unique situation, partially retracted retraction; final explanation, lingering-dread-of-the-unknown—I found "Killer Waves" oddly satisfying for the first 45 minutes. I'd learned: Unique Situation: Upwards of 10 ships per week are lost, possibly to "rogue waves" which tower 50 meters tall and punch holes through ships. Partial Explanation: Sailors tell tall-tales about tall waves. Complication: Scientists observe a rogue wave slamming into the Drauper oil platform on 1 January 1995. Partial Retraction: Sailors are not all liars. Turns out the warm Agulhas current running southwest off the South African coast mixes with cold water moving northeast creating swell conditions conducive to the production of rogue waves. Similarly Unique Situation: Happens twice in a week off the coast of Antarctica, but there are no currents like those off the South African coast. Partially Retracted Retraction: Currents alone cannot account for what happened off Antarctic coast. Final Explanation: Waves caused by math. Lingering-Dread-of-the-Unknown: The non-linear Schrödinger equation will strike again. I'm sure you can tell where dissatisfaction set in. Here is the actual explanation, from the transcript of a very similar show (presumably its narrator spoke with a British accent): The physics of the non-linear Schrödinger equation we can see in this simple example. In the beginning it doesn't seen like there's anything happening and we could all just give up and go drink a beer if we wanted. On the other hand we could keep moving forward and maybe something will happen. What we'll see is this central wave here's going to start to grow. It's growing because it's robbing energy from its two, two nearest neighbours so here it's starting to come up, you see it's growing, it's stealing energy from the nearest neighbours and these waves are starting to drop. See how this is coming down here. Look at that decrease and now in its full glory it's a very large wave, it has two smaller waves on each side and two rather deep holes in the sea around the peak. So what happens, you see, is that waves rob energy from other waves, use this stolen energy to grow, and form (in fully glory) very large waves surrounded by deep holes. And that, my friends, is how a rogue wave is formed. (By the by, here be the rest of this post. Insomnia is a brutal beast I tell you.)

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