How did the Moon end up with an orbit the perfect distance to cause total eclipses?
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The moon is very gradually drifting away from the earth. In the distant future it will be too far to completely cover the sun. In the distant past, meanwhile, it was closer, and the moon was always larger than the sun in our sky.
In other words, it’s the perfect distance *now,* and we only care because our civilization arose during that window. If this weren’t the case, then we wouldn’t have even realized that we were missing out; no one would be sitting around going “boy I wish the moon and the sun were the same size so one could *just* cover the other when they line up.”
It’s also *not* perfect; the moon’s orbit is elliptical, as is the earth’s orbit around the sun, and the moon’s orbit also doesn’t line up with the ecliptic. New moon only aligns with the ecliptic a couple of times each year (from our perspective), and for a total eclipse you still need the orbits to be at the right distance. If they’re not, you only get an annular eclipse (which is what we got last weekend), or a total eclipse that just grazes one side of the earth and no one really gets to see it. Total eclipses affect a relatively tiny part of the earth’s surface and if you live your entire life in one spot then chances are you will never see one. My idea of a “perfect” system would be one where the entire surface of the earth gets to see a total solar eclipse at regular intervals, perhaps once a decade or so, common enough that no one misses out but rare enough that they’re still appreciated.
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