Last week, I was checking my feed reader, catching up on all my favorite web comics. One of them is sci-ence, a comic you really should be reading. It's drawn (in part) by artist and science afficianado Maki Naro, and (like xkcd and Saturday Morning Breakfast Cereal) it's both funny and scilicious. I got a snicker out of the comic he had just posted, dealing with my pal Neil Tyson and the Moon. Go read it! Back yet? OK. Now, I know that just last night I was praising Neil, and today I have no cause to bury him. But I will nitpick a wee bit... First, of course, who hasn't wanted to chase Neil Tyson down the street while yelling incoherently at him? But that aside, I must point out that this explanation of the Moon Illusion, while very common, is not actually correct. The Moon Illusion is when the rising (or setting) Moon looks huge and fat, squatting on the horizon, but appears far smaller when up high in the sky. But it's not because you're comparing it with foreground objects! I've seen this illusion when out in the open plain, with nothing between me and the horizon but Kansas farmland, which is like a geometric plane, except flatter.
The real cause is actually a bit more subtle, and the combination of two different illusions. I wrote a pretty thorough explanation a while back... and I figured, why not let Maki know? So I sent him a note. He promptly replied, saying he'd update the comic. And when he did, I got quite the surprise... click the panel to see the whole thing. I'm honored to be included in the comic, which is almost entirely accurate. The science explanation is correct, and once I was lost in a park; ironically Central Park, not far from the American Museum of Natural History where Neil works... shortly before I was scheduled to give a talk there! I'll note that although it's not exactly my style to jump out of a bush at people -- scaring folks and potentially getting shot are things I generally try to avoid -- I am enough of a dork to interrupt a conversation about astronomy if it's going astray. Come to think of it, it's kind of amazing I never have been shot at.