Farewell to James Van Allen

Posted by jns on August 12, 2006

Physics^* tends to carry around all manner of homages to its creators and discoverers. Vast numbers of units of measure, constants, concepts, equations, effects, principles, and laws are named for famous scientists: Galilean Relativity, Newton’s Laws of Motion, Kepler’s Laws of Planetary Motion, Bernoulli’s Equation, Euler’s Equation, Laplace’s Equation, Boltzmann’s Constant, Planck’s Constant, Hubble’s Constant, the Compton Effect, the Zeeman Effect, Kelvins, Celsius degrees, Curies…. Obviously the list is not strictly endless, but it does go on quite a bit.

I’ve always found it a humanizing influence to acknowledge scientific pioneers this way, and a useful way for students of physics to learn some of its history as they go, which I also think is a good thing. I also find that it helps me remember which equation, constant, or effect is which — just imagine the mental chaos if all our equations and constants were simply numbered!

One thing that virtually all these nominal designations have in common is that the person after whom they are name is dead. There are a few exceptions, of course, for those that are associated with phenomena discovered more recently.

One such was the Van Allen radiation belts around the earth. They had been discovered in 1958 by James Van Allen. Van Allen and his team had built Explorer I, the first satellite launched by the US. The satellite carried only one instrument: a Geiger counter^#. The instrument’s readings led Van Allen to deduce the existence of regions of high-energy charged particles trapped by the Earth’s magnetic field. ^**

I went to college in Iowa (Cornell College, in Mt. Vernon, Iowa) in the late 70s. I knew about the Van Allen Belts, but hadn’t quite caught on to the fact that they had been discovered after I was born (albeit in my extreme youth: I was 2 years old). Thus, I thought of them as named for an historic scientist — if I thought of it at all back then.

Imagine my surprise then when I learned not only that Van Allen was a living, working physicist, but that he was also living and working at the University of Iowa, a mere 30-minute drive south through the corn fields from me! It was probably the only time I would be young enough and naive enough to react to something like that with such profound surprise — I had never imagined something like that! It seemed almost mystical at the time, since I was certainly still in awe of anyone who had something like that named for him. Since then I have met physicists with things named for them and they seemed like … people.^## It’s just as well, though, that I never met James Van Allen since, for me, he had mytical status and I’m sure I would have been embarrassingly tongue-tied.

James Van Allen died this past Thursday, news that seems surprising to me since — in my mind — he is immortal.

Here’s what Bob Park had to say in today’s “What’s New“:

JAMES VAN ALLEN: THE FIRST AMERICAN SPACE HERO, DEAD AT 91.

Almost nothing was known about conditions beyond the ionosphere when the US launched Explorer I on 31 Jan 58. The Cold War was at its peak, and the Soviets seemed to own space. Sputnik I, launched 4 Oct 57, carried no instruments. Sputnik II, a month later, could only send back Geiger counter readings taken when it was in sight of the ground station. In June, however, at a conference in the USSR, James Van Allen, a physics professor at the University of Iowa, announced that Explorer I had discovered the first of the two “Van Allen radiation belts.” Soviet space scientists were crushed; the “space age” was not a year old and already the U.S. had taken the lead in science. Two years ago I visited Prof Van Allen in his office at the U. Iowa. At 89 he was down to a 7-day work week. He showed me an op-ed he was sending to the NY Times in which he described human space flight as “obsolete” http://bobpark.physics.umd.edu/WN04/wn072304.html. I don’t believe they used it. Van Allen said using people to explore space is “a terribly old fashioned idea.”

———-
^*I’m sure this is true of many other fields, but I’m a physicist, so I’m talking about physics.

^#Named for Hans Geiger, one of its inventors in 1908.

^**Here are two pieces about the radiation belts: one more technical, one less technical; also, an article with lots of pretty pictures — be sure to scroll down past the section “Reading to be Informed Questions” to see them.

^##With maybe one exception (although we didn’t actually meet). The background is this: there was a famous textbook in quantum mechanics written by Eugen Merzbacher that was known to any physics student at the time; not surprisingly, given the familiarity of his name, Merzbacher also had a status that exceeded mere personhood. Once, when I was at a meeting of the American Physical Society, Merzbacher was there: I happened to stand in line next to him at a McDonald’s for breakfast. To this day it fascinates me to have heard someone of such exhalted status say: “I will have an Egg McMuffin, please.”

Doilies & Chaos Theory

Posted by jns on March 28, 2005

Kriston, at Grammar.police posted a fantastic picture of a crocheted sculpture in yarn: “Crocheted Model of Hyperbolic Plane” (1970s) by Daina Taimina. (He references this original article: “Crocheting the Hyperbolic Plane: An Interview with David Henderson and Daina Taimina“)
His reaction:

When I saw the images of Taimina’s crocheted hyperbolic figures, I was immediately struck by how instructive it could be as an applied tool to teach non-Euclidean geometry, because–well, I don’t know anything about crochet, but I get the sense that this is true–one could viscerally experience ultraparallel lines or even space curvature. It turns out that Taimina, in fact, invented the first workable model of Lobachevskian, i.e., hyperbolic geometry by abandoning paper and turning to crochet. Certainly makes a great deal of sense after the fact, doesn’t it?

Now, I’m quite serious in what follows, although it may not appear so.
He’s quite right about Taimina’s crocheted geometrics — they are fascinating and instructive as well. They suggest that there indeed could be more mathematical possibilities along the lines he mentions, regardless of whether one knows anything about crochet or not.

People who know me know that I know a bit about crochet, although I prefer working in thread rather than yarn. I crochet doilies. Obsessively. It serves the purpose of keeping my hands busy and productive when I’d otherwise just fidget. These days, since we watch television so rarely, I make most of my pieces in the car, when Isaac is driving. The problem is that, after doing this for some 10 years, one ends up with a lot of doilies — let’s say several hundreds — which is really more than one household can make use of. (Some of my work is displayed, for sale, at The Pansy Forest; there are still lots more for me to put up, however.)
Anyway, I’d never thought about making crocheted hyperbolic figures, although it’s a brilliant idea. I have, however, designed some of my own doily patterns, and the experience gave me the idea for a book about it. (This started several years ago now.)
The tentative title for the book is Doilies, Chaos Theory, and the Origin of the Universe. Seriously.
I don’t want to go into the entire story here, but I discovered what I felt were interesting and illuminating connections between chaos theory (concerning which I did some reasearch in my early graduate-student and post-doctoral days) and creating doily patterns.
Most doilies are chrocheted “in rounds”, worked successsively in thin rings from the center to the outside. Traditional doily patterns, particularly those that make use of a motif called a “pineapple” (sometimes “acorn”), typically develop their patterns over many rounds — that is to say, the patterns emerge one round at a time over the course of completing, say, 10 or 20 rounds.
Now, at the same time the pattern is emerging, it is necessary that the number of stitches in each round increase (relative to the previous round) in fairly strict geometric ratios. There can be a bit of fudging for a round, maybe two further from the center, but one cant’t get away with it for long.
Doily patterns, therefore, are highly constrained systems, and to set out to create a pattern over the course of many rounds requires planning, good luck, and a cooperative pattern. They don’t always go the way one wants.
Another way to put it is to say that doily patterns can show extreme sensitivity to initial conditions: what is allowed to happen on round 25 can depend critically on what happened on round 6. Sensitivity to initial conditions is a defining characteristic of some “chaotic systems” (at least it characterizes the motion of the systems through its phase space, but that’s a longer version of the story.)
Nevertheless, doilies do not look chaotic. Instead, they are amazingly developed mathematical patterns in many cases. How they can look so organized and yet share these characteristics with certain types of chaotic systems interests me. As for the origins of the universe: contemplating the constraints on how doily patterns emerge brings one pretty easily to considering the anthropic cosmological principle (which I tend to think is mostly bunk) and such topics.
I will be the first to admit that there may not be a big cross-over audience for a book that covers antimacassers and modern ideas about dynamical systems and self-organized complexity and such, but that may not stop me. If only I could figure out how to type the manuscript while I crochet the doilies.