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earlier, i read something about a lunar eclipse in the paper. earlier. that made me track down my old astronomy notes from freshman year. they were on my shelf with all my other notebooks and sketchbooks, and mixed in with the stuff from my german and english classes i was taking at the same time, but i was able to find my notes on the moon easily enough since i had highlighted a bunch of them for a test or something. it's crazy what you'll learn and just forget about even if it's really amazing stuff. i love this kind of stuff. things like the reason eclipses don't happen more often is because the moon orbits the earth at a five degree tilt. i think it's in relation to the earth's orbit or something but i don't think i really wrote that part out too clearly. i don't know. i had a small diagram that seemed to show how it worked. anyway, things like that, and that there's a name for a lunar month like syn-odic, a synodic month! it's only twenty-nine point five days long. which compared to a normal month -- and did you know that light traveling from the moon to earth takes one and a third seconds to, you know, travel that distance. also, lunar eclipses last between one and two hours, so they average about an hour and a half, but that solar eclipses last an average of three minutes with the longest possible one lasting about seven and a half because of how the earth's rotation and the moon's orbit, um, effect each other, or, that that's as long as it's physically possible. there are names for things like umbra and penumbra that describe which part of the shadow is, whether or not an eclipse can occur. the moon must pass through the umbra for an eclipse to occur and only a partial eclipse will happen if it only goes through the penumbra because that's the part that's like half shadow or, it's caused, it's a dimness of the sun's light caused by the refraction of light around the earth or how light bends around objects. the whole einsteinian bit about light having mass or volume or, the thing they actually proved with a solar eclipse in south america some time in like the 1950s or so. anyway, a partial eclipse happens when the moon only skims the umbra and a portion is blocked out, if it only enters the penumbra, the other part, it just gets dimmer i think, but not like a shadow or anything. that's it! less light reaches the surface or is reflected back. that's what the penumbra does. there's less light reaching the surface of the moon because it's being refracted away by the earth and so the moon appears dimmer to us. that's like sometimes, when sunlight is refracted through the atmosphere it causes the moon to look like a reddish coppery moon instead of white. it's why the sky is blue, i guess. the red light escapes but the blue light keeps bouncing about trapped in the atmostphere. the red light is all that reaches the moon sometimes and makes it a red moon, or a blood moon. i'm not sure if that's what a blood moon is, though, that could be something else, like a harvest moon or once in a blue moon. mike told me that a blue moon isn't actually a blue moon, that the moon isn't actually blue. it's when there are two full moons in the same month or something. well, anyway, i ended up copying the notes on the solar eclipses too and it's really crazy to think that the only reason that a full solar eclipse can occur is that the sun is four hundred times the size of the moon but also it's four hundred times as far away from us as the moon. so because of the coincidence of space and the creation of our solar system and stuff, the moon appears to be the same size as the sun when it's viewed from earth, which allows the moon to block out the sun during an eclipse because it's about the same size. but that doesn't always happen. well, the way things orbit and all. the moon or maybe the earth are at different positions or distances from one another at times and when the exlipse occurs, the moon isn't large enough to block out the sun completely. that's called something like an annular eclipse, or an-nuval, or an-nulal, well something like annular. it's caused by the umbra of the moon not reaching the earth or something... |
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