Monday, July 31, 2017

Looking For Bowhead Whales One Glass of Ocean at a Time

In a recent SETI Talk celebrating the publication of Sarah Scoles' biography of Jill Tarter, Seth Shostak reminded me of a puzzling analogy that Tarter likes to use to explain why we haven't found a signal from an alien civilization yet.

Jill likes to say that [if] you go to the ocean and take out a glass of water and you don't find any bowhead whales or something [you wouldn't] conclude that there aren't any whales in ocean. She's emphasizing the fact that the sample size has been very small. (29:51, lightly edited.)

In this analogy, however, it's not so much the sample size as the sampling rate or resolution of the search that is the problem. You can't catch a bowhead whale with a highball glass; so you're looking for something in a way that precludes you from finding it. I think other SETI researchers sometimes jokingly use the parable of the drunk who's looking for his keys under the street light. When asked where he lost them, he points down the street a ways. "Why are you looking here then?" we ask. "Because the light is better," he replies. This is not a joke SETI researchers should be telling. It's literally on them.

Since Tarter is a woman, the same SETI talk begins with an obligatory discussion of gender discrimination in science. I hope women in science will soon band together against this theme—the obligation in particular. Let them talk about their struggle to discover the truth, not their struggle as women. But I digress. Tarter addresses this topic by talking about what happened at Starmus this year, when she was, shockingly, exposed to gendered humor. I ended my post about that incident with a jab at Tarter's demonstrated inability to sort signal from noise. In my view, gender activists are not looking for bowhead whales one glass of water at a time—though I think SETI is looking for aliens that way, I'm afraid. Rather, their null hypothesis seems to be finding pure H20 in a glass of raw sea water. In their surveys, of course, they're constantly finding it full of salt and life. Shocking!

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