It seems to be. If we look at the other moons in the solar system there is a whole range of apparent angular sizes for satellites as seen from the surfaces of the planets. Earth just got lucky, besides, there are probably selection effects at work. I am willing to bet that it is probably difficult for planets close to the Sun like Mercury, Venus and Earth to have satellites in orbits much larger than the Moon's, and there is probably another selection effect which caused small bodies in the inner solar system to either get ejected or absorbed during the time when the solar system was forming. This is just a hunch on my part, but the fact that the Moon is as big as it is, and just fits over the Sun's disk may not in the grand scheme of things be that big a deal. Still, you DO wonder about it don't you?
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