It’s been a good week for astronomy here in Lake Wobegon, my hometown….
First of all, I got a 96 on the first astronomy exam. Our professor was LIVID with the results from the first set of papers she graded: “One A, one B, one C, the rest F” out of 21 papers. Then she came over and told me under her breath, “You are not one of the ones I am worried about.” The next day we got our results, and some of us could finally breathe. Another student did get a 100, so it was possible. Goals, it’s good to have goals.
Second of all, we’re studying the electromagnetic spectrum now. On the one hand, I kind of feel sorry for the “student” who tried to explain (in an extra credit essay, no less!) how Eratosthenes measured the circumference of Earth using the angle to the Moon and the speed of light, and wonder how he’s (or “she’s,” don’t want to be sexist here) going to comprehend this new material. On the other hand, not my problem, and personally I find this stuff fascinating.
emission spectrum for silicon
It’s super extra fascinating for me because I have actually knitted a representation of an emission spectrum, in the form of a scarf I made for a friend last year. So as she’s explaining Balmer series of hydrogen, and how light of certain wavelengths is given off when electrons jump between energy levels around the nucleus, I’m having flashbulbs and fireworks going off in my head as I think, “I GET IT NOW!” I knitted an emission spectrum for carbon. In my head I could see the inverse, an absorption spectrum for carbon. Instead of being mostly black with the occasional thin stripe of color put in, it would be a long, long rainbow with the occasional thin stripe of black representing the wavelength at which the energy is absorbed. (Then I visualized a double-knitted version with an emission spectrum on one side and an absorption spectrum on the other. But let’s not go too crazy here.) So. I knitted it before I could understand what it meant, and now I really get it. Sometimes I wish I could knit as fast as my mind can think. Then I remember that sometimes my mind goes off in the wrong direction. That would be a lot of ripping out of stitches, and a lot of psychic pain. Not the best plan.
Thirdly, I corrected Copernicus. Let me explain. Last semester I found that I could put Isaac Newton’s Principia Mathematica on my Kindle. It was free, or 99 cents, or something ridiculous like that for a core text in the history of science and math, so I clicked and Made It So. This semester I’ve been accumulating other core scientific texts that are free or cheap, and I have a folder on my Kindle for them. This includes Copernicus’s De Revolutionibus, or On the Motions of the Heavenly Bodies (since I’m reading a translation in English. I always thought I would take Latin in college, but I never did). It opens with a prose overview of the orbital motions, then launches into some geometric proofs about the various equivalencies to be found in the angles and chords of spherical triangles. Now, I haven’t done a geometric proof of anything since about 1982, and I KNOW we never dealt with volumetric solids or spheres, so I was pretty happy when Copernicus got done with that part and turned his attention to star coordinates, the ecliptic, and stuff like that which we’ve already covered in astronomy lab.
He was talking about being in a region where the stars never rose or set, but just circled in the sky. All right, fair enough, imagine standing at the North Pole and looking up. There you go, the stars rotate around the North Star but never rise or set. Done. Understood. Then he went on to state that, in this location, day would last for six months and night would last for six months.
Now, if you’ve been to Alaska, or watched a TV special about Alaska, or even watched Northern Exposure, you know that there are a couple of days in their year when the sun never really goes below the horizon enough to say that it “set.” It’s the “midnight sun.” Now, maybe people play baseball when this happens and maybe they don’t. I don’t have first-hand evidence for it. But that’s certainly a big difference from having day for SIX MONTHS and night for SIX MONTHS.
So I wondered, maybe the tilt of the earth’s axis makes a difference here. The earth isn’t straight up and down in space; its axis is tilted 23.5 degrees and wobbles as it rotates. I highlighted the text electronically, then showed it to my astronomy professor. And she said I was right!