Craig Miller -- the one they call "Junior," sometimes "the Joonz" -- committed an error this morning.
I stared at the radio, my piehole agape.
I'm not sure I can go on.
One's existence has so few certainties in this uncertain world. I thought Craig's freedom from error was among them.
In this, I was apparently also in error.
He corrected the error, more or less, in the next segment. But his correction indicated that he did not understand his error.
He was reprising the flat-earth guy from the day before. He reported that the flat-earth guy had said that the moon always shows the same side to the earth.
Craig -- excuse me, I have to go get a glass of water -- scoffed. He said that of course we see the moon rotate and show all of its surface area to the earth. It's why we can't always see the man in the moon, he said.
I'm thinking -- his phone must be melting.
And indeed, in the next segment, he issued a correction, but he didn't understand it. He had been advised in the interim that the moon in fact, always does show its same side to the earth owing to a tidal phenomenon (it's called "tidal locking"). (In fact, there's a slight rotational wobble ("libration") that lets us see a little more than half of the moon's surface from the earth because its orbit is not perfectly circular.) What froze his mind was this: The moon's rotational period around its axis (spinning) is equal to its period of revolution around the earth (orbiting). So what? he seemed to be saying; he still did not understand why we did not see the moon rotate so as to see all its surface.
It's because we view the rotation and the revolution at the same time from our vantage point here on terra firma. Instead, let's expand our frame of reference -- out to the sun, for example. (Yes, I know you can't stand on the sun. The old joke: "I want to be the first man on the sun." "It's too hot." "I'll go at night.") Imagine you're on the sun looking back at the earth and the moon. Now remove the earth from the picture to eliminate the distraction. What do you see? You see the moon rotating on its axis every 27 days and showing you all of its faces -- and it will always be full because the sun is what makes the moon shine.
Which leads us to the question of why Junior thinks that you can't always see the man in the moon. It's not because he isn't there, having rotated out of sight -- it's because the moon's rotation with respect to the sun just described causes its phases from our vantage point on earth, so some of that always-facing-the-earth-surface disappears and reappears every month. Or else it gets eaten and then spit back up by a space monster, I'm not sure.
I'll leave you with a fun moon fact. The moon is the largest planetary satellite in the solar system as a percentage of the size of its planet. It is the only natural planetary satellite in the solar system whose orbit always curves towards the sun. That is, if you were to go way, way north of the sun's north pole and look down on the solar system, and then took the earth away and looked at the path of the moon's orbit over the course of the year, you would see that the moon's orbit would look like a twelve-sided thing where the sides curved gently toward the sun, and the corners curve more sharply toward the sun. But none of that path would ever curve away from the sun. The earth and moon are, in effect, something of a double planet.
I'm going to go lie down. Feeling unwell. May be last article.
