Posts tagged ‘mosquito’

July 8, 2010

Oscillation

by Carl Dyke

One of the basic misconceptions about ‘global warming’ is that there should be a smooth upward trend of temperatures all over. A cold winter means it can’t possibly be warming. But actually climate is made up, as I’ve recently learned, by a whole mess of coupled quasi-oscillators, systems that swing through a series of states tending toward return to origins (seasons), but with drift. In this case the drift is the warming, but the oscillation means that at moments in the linked oscillation parts of the system may well be swinging low while other parts are swinging up.

I was sitting outside just now playing a game I grimly enjoy with a simple natural quasi-oscillator, the mosquito. I have this tennis-racquet-looking device that uses batteries and a metal mesh to deliver a mild but mosquito-killing shock. In the process of getting good at killing mosquitos, first with my hands and then with this newfangled mosquitocidal contraption, I’ve noted that mosquitos’ basic move while feeding is to oscillate. They loop back and forth around a target area, drawing nearer and swinging farther until the coast clears, at which point they shorten the period of oscillation down to a landing. With feeding mosquitoes, like climate, there is no straight point-to-point flight.

Because the mosquitoes’ period and amplitude of oscillation vary their flight can look random, but it’s not – it’s non-linear but quite orderly. This makes mosquitoes almost as hard to track and swat as a purely random path, but pure randomness wouldn’t get them food. So my tender white flesh is an attractor (perhaps a strange one) around which the mosquitoes oscillate, reacting to movement and opportunity by swinging out or swinging in, with the oscillations drifting toward a meal.

Waving the killer doohickey around randomly will occasionally intersect one of these paths, but what works way better is to swing it back and forth in the same oscillating pattern as the mosquitoes, only slightly faster than them so that the linked oscillations have the chance to intersect on both the way out and the way in. If you’ve ever tried to stop someone (maybe yourself) on a swing you know how this works. You want to be pushing forward while the swing’s going back, and back when it’s going forward. Get this counter-period wrong and you just amplify the swing or knock the swinger on his ass.

Can we do something like this on a global scale with ocean currents, gas concentrations, absorbtive/ablative surfaces, butterfly wings and so on to manage the climate? Wow. Well anyway, be sure to turn off the lights when you leave.