I probably heard of Wethersfield, Connecticut, although I forgot about it until teaching a statistics course last academic year. The town vanished from my memory shortly thereafter, because as far as I know I’ve never been there or known anyone who had. The rather exciting meteor strike in Russia last week brought it back to mind, though, because the town worked its way into a probability book I was using for reference.
Here’s the setup: the town is about 14 square miles in area, out of something like 200,000,000 square miles of land and water on the surface of the Earth. Something like three meteors of appreciable size strike the surface of the Earth, somewhere, three times a day. Suppose that every spot on the planet is equally likely to get a meteor strike. So, what’s the probability that Wethersfield should get struck in any one year?
With that worked out the follow-up question, which becomes the obvious follow-up question when you learn why I think I probably heard of Wethersfield before the statistics course I taught, is what the chance is Wethersfield should be struck by two meteorites within an eleven-year stretch. There are at least two sensible ways to do that calculation.
What makes this a question worthy of getting into a statistics textbook is that Wethersfield was after all struck by meteorites, first on April 4, 1971, and second on November 8, 1982. The first strike was a touch before my time, and not really noteworthy enough to draw attention outside Connecticut, although the second launched the town into that fascinating realm of places designed for Ripley’s Believe It Or Not and probability word problems, and I’d have been the right age to be captivated by the evening news reporting on the event.
I have found mention of Wethersfield outside the world of probability problems by investment agencies, who want to point out that it may be ridiculously improbable that something might happen, but that doesn’t mean that it won’t. I am not personally convinced that meteorites in New England offer any financial planning advice, but I’m hardly in a position to say someone else is managing his money poorly.
Curiously, the two meteorites apparently struck locations about a mile apart, which should make the event even more remarkably improbable. But perhaps stating that two meteors strike a mile apart, eleven years apart, isn’t quite as naming a town to be hit.