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Abundance estimation is a big problem in ecology (and other fields), and they’ve developed some clever ways to estimate population sizes without doing an exhaus
by mattkrause 7y ago
Abundance estimation is a big problem in ecology (and other fields), and they’ve developed some clever ways to estimate population sizes without doing an exhaustive census.
One popular approach is a capture-recapture experiment. On your first trip, you find as many of your targets as possible and mark each one. With turtles, you might paint something on the shell; here, it might be something like determining its orbit and other characteristics. You wait a bit, and search again (starting from scratch), but this time you separately record the number of “new” specimens and the number recaptured. A tiny bit of algebra from these three numbers gives you an estimate of the population size.
- joemag 7y agoIt comes with a bias though, since your searches will bias towards finding asteroids that are easiest to find using your search method.
- mnky9800n 7y agoShow me a measurement that doesn't come with bias
- Bootvis 7y agoI have one apple.
- ccapo 7y agoCorrect, and since that bias is towards larger NEOs, which are relatively easier to detect then smaller objects, they can be reasonably confident about that estimate. It is the medium to small size NEOs that are the most worrisome. They are harder to detect, and hence harder to estimate how many are out there.
- BurningFrog 7y agoSeems like a bigger problem for turtles than for asteroids. I mean, asteroids don't deliberately hide. Sure, some are darker and/or have a less visible radar profile or whatever, but the variations seem manageable.
- craftyguy 7y agoThey don't deliberately hide, but (as mentioned in the article) they can vary dramatically in how visible they are to us over time if, for example, they have a highly eccentric orbit.