Wednesday, February 20, 2008
Learning something new!
Current mood: tested
Well, I feel a little dumb!
I fancy myself as being pretty informed. I've been reading nearly non-stop since I was a kid, and a lot of that is factual stuff from a wide range of interests. I've picked up a pretty good store of random, (nearly) useless knowledge. It usually serves me well as I try to answer Littleman's endless stream of questions.
Tonight, there was a total lunar eclipse. After getting the boys ready for bed, I took everyone outside to admire it- by that time, the Earth's shadow was covering about half the moon. I explained to Littleman and Sweetcheeks that the moon was getting covered up by the Earth's shadow, and we talked about how we see shadows when an object (ie; the Earth) gets in-between the light source (sun) and the surface we are looking at (moon). We made our own shadows on the living room wall before heading up to bed.
A little while ago, I was thinking about my explanation, and I realized that if I was correct (which I was), then I must have the moon's phases all wrong! All this time, I've had a vague notion that we see the phases of the moon because of the shadow that the Earth casts. But of course, that can't be right! Feeling like a ninny for not ever thinking of this before, I went googling for an answer. And of course, I found one:
Check it out- it's a very clear explanation with a great visual!
So it turns out that the moon is always half illuminated and half in darkness (except during a lunar eclipse). We see phases of the moon because we are usually looking at the moon from the side, seeing only part of the illuminated side and part of the darkened side. The phases change in a cycle as the moon orbits around the Earth, changing the angle from which we view it. Which makes sense, because the line between light and shadow is crisp for a moon's phase, but all soft and fuzzy in an eclipse. Ah ha!
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Thumbs-up for that site on moon phases for remedying my ignorance!
2 days ago