I remember now, I remember now, why they call it Freebird

The WSJ and Photodude discuss the tradition of yelling "Play Freebird!" Growing up, I always sort of assumed this was a south-of-the-Mason-Dixon-Line thing. Mike Doughty of Soul Coughing makes the drastic suggestion that musicians kill the joke by actually playing Freebird.

Photodude's commenter "emcee fleshy" mentions that "I also thought, in third grade, that the F-word had just been invented." Me too.

Hyperion again

The best Cassini picture yet of Hyperion:



This is finally good enough, and from such an angle, that I can compare it to Voyager images and identify one surface feature, the cliff that appears as a dark streak about a third of the way from the left end: that's Bond-Lassell Dorsum.

Irregularly shaped objects are not so unusual in the solar system; they are probably more the rule than the exception. What's unusual about Hyperion is that it is so large for such an object: more than 400 kilometers along its longest axis. Mimas and Enceladus are only slightly bigger. It suggests that Hyperion is a chunk of some larger object chipped off in a cataclysm. Neptune has an irregular moon called Proteus that is slightly bigger, but even that is much closer to being a sphere.

The other thing that is unusual about Hyperion is that its rotation is chaotic. It has no fixed rotational axis, and its orientation cannot even be predicted over any extended length of time. Camping on Hyperion would be a bizarre experience, with the horizon bearing no particular relationship to the local vertical and the day/night cycle changing radically every once in a while.

I remember somebody on sci.physics years ago posing it as a riddle in the interpretation of quantum mechanics: the dynamic chaos of Hyperion blows up even quantum uncertainty in its orientation in short order, yet, like Schrödinger's cat, we see it in a definite orientation. What gives? (I have my own thoughts on the matter and do not think it is a real paradox at all, but I'll let you ponder it.)

I was going to say that it's unique in this regard, but the Nine Planets site says that the asteroid 4179 Toutatis also rotates chaotically. I suppose it shouldn't be a surprise. Like Hyperion, Toutatis is a highly irregular object whose orbit is near, and in resonance with, that of a much larger body that can perturb its orderly rotation through tidal effects. In the case of Hyperion it's Titan; Toutatis is in resonance with Earth.

Correction: Toutatis is actually in resonance with Jupiter, but it does make frequent close approaches to Earth.