Eclipse II

I poked my head out the patio door to see if the moon had come out from behind my building. Imagine my delight to see it was visible and the eclipse was not yet complete. Of course I couldn’t help taking a few photos, especially since I didn’t need to get bundled up or use a tripod.

IMG_4890.CR2: 30D, EF 400mm 1:5.6L @ 1/400, f/5.6, 100 ISO

IMG_4890.CR2: 30D, EF 400mm 1:5.6L @ 1/400, f/5.6, 100 ISO

What you see here is the evidence Aristotle used to prove the Earth is spherical. The shadow cast on the surface of the moon is round, and what casts a round shadow besides a sphere? A disc casts a round shadow if held perpendicular to the light rays, but a lunar eclipse near the horizon also shows a shadow that’s round, not elliptical. Therefore, the Earth must be a sphere.

Later another Greek, Aristarchus of Samos, took things a step further and not only calculated the relative sizes of the Earth, moon, and sun, but the distances between them. Granted he was wrong because he had no instruments capable of accurate angular measurement, but his logic was correct. Had he been able to accurately measure angles down to fractions of a degree, he would have calculated the correct values. Aristarchus also determined the planets revolve around the sun.

All this, seventeen centuries before Copernicus.

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One Comment

  1. Posted February 23, 2008 at 02:18 | Permalink

    I am simultaneously entranced and jealous. Entranced because the picture of the eclipse is divine, and jealous because I was unable to view it due to the miserable Houston weather. Rain, rain, and a little more rain just in case we missed it. Thanks for sharing your pics.

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