Monday, January 3, 2011
Spring Songs Celebrate Perihelion
This morning, at a brisk 12 degrees, I heard the spring songs of our black-capped chickadees. Yes, it's sunny. I suppose you could try to fool yourself into thinking it's warm outside. Or that spring is just around the corner. But we Minnesotans know better. We have another 3 months of snowy weather ahead of us.
So, exactly what is the chickadee fee-beeing about? I learned that today we are at perihelion: the closest we'll be to the sun all year. And somehow the chickadees know it.
From today all the way until July, we'll be gradually moving farther away from the sun in our elliptical orbit. You can read more about this, and see some cool photos of the sun at both perihelion and aphelion (when we're farthest from the sun) on Phil Plait's Bad Astronomy site.