by CKR
I commented a while back that I’m hearing robins and towhees at night. The Summer 2006 Birdscope from the Cornell Laboratory of Ornithology told me why. Mark Miller, a biologist in Florida, noticed this behavior too, and checked it out.
He found that robins are singing more at night, in response to streetlights and other bright lights that are on all night and published his findings in The Condor. There's a bright streetlight just down the hill from me.
It’s nice to have a question answered that way. Science asks questions and comes up with provisional answers, the questions sometimes going unanswered and the answers sometimes incomplete or even wrong. That’s why I am irritated by “what we learned in school was wrong” in stories like this one about the International Astronomical Union’s current deliberations about the definition of a planet.
It was what we knew at the time. Once upon a time there were five planets, the ones we can see just by looking: Mercury, Venus, Mars, Jupiter, and Saturn. People noticed early on that these objects don’t twinkle like stars, and they move around relative to stars. Venus, for example, rises only an hour or so before the sun just now. I saw it rise this morning big and bright over the mountains, and, on checking the charts, see that I should have looked for Mercury too. In a few more weeks, Mercury will set after the sun in the evening, Venus too in a couple of months.
After we got telescopes, we found a few more planets: Neptune, Uranus, and Pluto. Now we’ve got better telescopes and computer-aided analysis to pick out more of the larger bodies in our solar system. To be clear in their discussions, astronomers have to develop a definition of a planet. The objects have been there for a long time and will continue to be there, no matter whether we’ve been seeing them or what we call them.
What will educators insist that students learn? I think it makes sense to memorize the easily visible planets and to have some idea of what they look like, so you can say, yes, that’s probably Jupiter in the evening sky, brightly white, a few of its satellites visible through binoculars.
And it would be good to know that there are other planets (by whichever definition the IAU decides on) that we can’t see just by looking and some things about the instruments and methods used to find them, along with what we know about how the planets formed. Focusing on those silly mnemonic sentences has nothing to do with science.