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    Archive for "Nov 11 2010"

    Under an Iranian sky, a Tuscan comes to mind

    Babak A. Tafreshi, Crescent Pair. Used by permission of the photographer. The very old Moon and the planet Venus, both in their crescent phase, as seen over Iran’s Alborz Mountains just before sunrise last Friday. Can you see them (the Moon and Venus, not the mountains)? Look closely. Click on the image to get a high-resolution version. And make sure to see more of Tafreshi’s terrific images here and here

    It’s a beautiful set, isn’t it? The Moon and Venus often line up nicely in the evening or morning skies, but this is truly amazing. The Moon is so close to being new that it’s barely visible at all, and the crescent phase of Venus comes through bright and clear. Mr. Tafreshi certainly knows how to use a zoom lens.

    For the most part I’d like to leave this image as it is, and not babble about it, but this time I just can’t restrain myself. The crescent Venus reminds me of something.

    Although there had been reports of naked-eye observations of the crescent Venus before and since, the planet’s full range of phases was not observed until December 1610.  This is the month that Galileo Galilei, with his newly-invented telescope, determined that Venus’s phases differed from those that would obtain within the prevailing system of the day, the geocentric model of Ptolemy. While Galileo is not best known for this today, his observations of Venus constituted the strongest evidence he ever held against that model. However, he could never prove the validity of Copernicus’s Sun-centered model — which was not Sun-centered — he so believed in, because there were other competing systems he could not rule out. He thought he could prove the truth of the Copernican system through his theory of the tides, but his theory was wrong (a fact his opponents were well aware of). But, of course, despite his ridicule of Kepler for proposing that the tides were caused by the Moon and his belief that the planets’ orbits were circular and that Ptolemy‘s epicycles and eccentrics were therefore necessary, he was right about the Earth going around the Sun. So we remember him for that.

    Hmm. It strikes me that I should not unleash my full opinion about Galileo at this point. This is supposed to be a light and friendly post. Some day when I’m feeling particularly fine and full of piss and vinegar, I’ll give Galileo — and the idea that he was a martyr for science — a thorough treatment.

    But not today. Today I will get on with my little life, which is so amazingly blessed.


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