So I Had A Post Here..

But it disappeared. It took me hours and hours to write: I'd been working on various versions of it basically since my last post went up. I finally got it into what I thought might be a finished form at 9 PM, last night, and saved it, thinking I'd give it a last once-over for polishing and probably a few teaks to the wording here and there before publishing it.

And it was all gone. Every last word.

I didn't know what to do. I'm already behind schedule, so I had to post something. But I really don't want to go back and rewrite all of that yet. So instead, I'm going to talk about a discovery I made in writing that last post: writing about physics is really frickin' hard! No, seriously; its probably the hardest thing I've ever tried to do in my entire life. If I try to be complete, the writer in me bemoans the excessive length. If I try to be succinct, the educator in me lectures that no one's going to understand what I'm saying. If I try to be clever, the physicist in me rants that I'm skating by essential details.

Anyway, this whole experience has been somewhat discouraging. If I had to pick what I considered my two strongest skills, they would most definitely be physics and writing. That I can't seem to find an elegant way to combine them has sharply called into question my abilities both as a writer and as a physicist. If I'm as good a writer as I think I am, why can't I find a way to cleanly and elegantly convey the physics I'm trying to discuss? And if I'm as good a physicist as I think I am, why don't I seem to understand it well enough to write about it?

Fortunately for you readers, small doses of self-doubt and frustration seem to provide fertile ground for posts. Expect to see more on this topic in the future. My friend Lisa suggested I should just bite the bullet and serialize the physics posts. Since she's usually right about, well, everything, that's what I'll probably end up doing. The essential worry is that on the one hand, I don't want to be fifteen posts to developing a single topic, while one the other hand I don't want to be opening my posts with something along the lines of  "Today, I want to talk about the polhode of a torque-free, rotating, rigid body, which, as every good physicist knows, rolls without slipping on the herpolhode lying in the invariable plane"*.

Next time, I will probably talk about Minority Report, having finally watched it for the first time.

Until then, may your moments of self-doubt and frustration also prove constructive.

*I didn't make that up, by the way. There really is a thing called the polhode: it's the path traced out by angular velocity vector of of a freely-rotating, rigid body on the body's inertia ellipsoid. A theorem of classical physics called Poinsot's Construction shows that as the inertia ellipsoid rotates with the body, the polhode rolls without slipping on a single fixed plane: the curve traced out by the point of contact between the polhode and the plane is the herpolhode. It's a piece of knowledge which holds the dubious honor of being both singularly useful and singularly useless. Useful in the sense that it shows that the range of motion of a freely-rotating body is much more severely constrained than it might appear, but useless in the sense that it is always more convenient to work from the constraints themselves to find the motion of the body, rather than trying to extract the motion from this construction.