How Physicists Always Get it Wrong

A few months ago, Nature Physics published an article about an eventual overthrow of evolutionary theory. It's seen often enough - and in different fields. Sometimes there is legitimate grounds for strong skepticism, sometimes it's contrarianism masquerading as skepticism and often, as in the aforementioned publication, it's a case of experts speaking outside their expertise (something we do at the Bayblab quite often). In a humourous paper entitled "A Simple Model of the Evolution of Simple Models of Evolution" [free pdf] the authors explain how it can happen, using an explosion of evolutionary models made by physicists as an example:

The question presents itself: why are we being deluged with such models? In the spirit of the field, we present a simple evolutionary model of this process.

1. A physicist runs across or concocts from whole cloth a mathematical model which is simple, neat, and contains a great many variables of the same sort.
   
   
2. The physicists has heard of Darwin (1859), and may even have read Dawkins (1985) or some essays by Gould, but wouldn’t know Fisher (1958), Haldane (1932) and Wright (1986) from the Three Magi, and doesn’t dream that such a subject as mathematical evolutionary biology exists.
   
   
3. The physicist is aware that lots of other physicists are interested in annexing biology as a province of statistical physics.
   
   
4. The physicist interprets his multitude of variables as species or (if slightly more sophisticated) as genotypes, and proclaims that he has found “Darwin’s Equations” (cf. Bak et al. (1994)), or, more modestly, has made an important step towards eventually finding those equations.
   
   
5. His paper is submitted for review to other physicists, who are just as ignorant of biology as he, but see that it’s about equivalent to the other papers on evolution by physicists. They publish it.
   
   
6. The paper is read by other physicists, because at least it’s not another derivation of specific heats on some convoluted lattice under a Hamiltonian named for some Central European worthy now otherwise totally forgotten. Said physicists think this is cutting-edge evolutionary theory.
   
   
7. Some of those physicists will know or discover simple, neat models with lots of variables of the same type.

They continue:

[O]ur model predicts that simple statistical-physical models of evolution will continue to proliferate until either (a) all the available models are exhausted, or (b) they become as common and as boring as any other subject in the statistical physics literature, or (c) physicists learn some actual biology. We are not entirely confident that the third limiting factor will become operational before the others.

So there you have it: this will continue to be a problem until everybody learns more biology.

Of course, as much as we would like to think so, this isn't limited to physicists, even if they aren't as humble as us bio-types. And it's really just an extension of what we often lament in science writing (and other journalism) - poor understanding of the subject and headline grabbing, like the title of this post.

Experimental Physics a la Canadien (or Canuck Anthropology?)

OK, so we don't always get the calculations right. But you can't say we don't give it our all. This video of Kenny Powers' attempted cross-border "Superjump" over the 1 mile wide St. Laurent river is classic Canadiana all the way. As are the sweet custom mods on his pimped-out, jet-powered, Lincoln Continental. You can bet this idea was conceived after way too many cases of Labatt's 50. And it's certainly a cultural relic you won't find the likes of in post-NAFTA Canadia!

Popular Science has a breakdown of the physics:

"If, as the narrator informs us, the car achieves a takeoff speed of 280 mph, then using the equations of projectile motion, we can easily calculate that without air resistance (estimating a launch angle of about 30 degrees) the maximum distance the car could achieve is around 1500 meters, or just short of a mile. (I'll leave it to those of you with a little physics background to confirm this is true.) However, at speeds of this magnitude, air resistance will have a major effect on the flight of the car. The force of air resistance is proportional to the square of the velocity, so if you double the speed you quadruple the air resistance. Incorporating the effect of air drag into the calculations we find that Kenny won't even make it a quarter of a mile before falling ignominiously into the river."

Ooo. A little harsh. Come on guys, hind-sight's 20-20 right? Anyway, check out the video and judge Kenny's physics for yourself:



Further reading: For those unfamiliar with the psychology of the male Canadien and/or interested in further exploring Canadian anthropology through the miracle of YouTube Video, see also The Best Of Ron Hextall, Canadiens vs Nordiques 'Good Friday brawl' 1984, The Never-Ending Bench Clearing Brawl of Canada vs Russia 1987 at the World Juniors, the seminal National Film Board of Canada mockumentary "FUBAR", and Canadian television favorite "The Trailer Park Boys".

Physicists are crazy

Over the holidays I was reading about entropy and what it means to quantum mechanics. Apparently all the formulas of quantum mechanics are time-symmetric, meaning they have no time-directionality. The question was, how do we get a time arrow and things like directionality of entropy if these principles are not present in the underlying quantum physical laws. In other words, in quatum mechanics you can find the equations that govern a glass reassembling itself from fragments on the ground, and filling itself with the water spilled on the carpet and jump back on the counter next to you playing wii tennis. Entropy on the surface seems a very anthropic principle, since we are needed to judge what is disordered and what the direction of time is. Of course there are good explanations involving phase space that kind of explain entropy but it still seems odd that quantum mechanics is symmetric. On this topic, I also recently stumbled across some great lectures by non other than Hans Bethe entitled quantum physics made relatively simple, and a personal entropy calculator, perhaps armed with these you can make sense of this connundrum. It's never too late, even the reverse-sprinkler problem of Feynman was recently elucidated.... "We discuss the reverse sprinkler problem: How does a sprinkler turn when submerged and made to suck in water? We propose a solution that requires only a knowledge of mechanics and fluid dynamics at the introductory university level. We argue that as the flow of water starts, the sprinkler briefly experiences a torque that would make it turn toward the incoming water, while as the flow of water ceases it briefly experiences a torque in the opposite direction. No torque is expected when water is flowing steadily into it unless dissipative effects, such as viscosity, are considered. Dissipative effects result in a small torque that would cause the sprinkler arm to accelerate toward the steadily incoming water. Our conclusions are discussed in light of an analysis of forces, conservation of angular momentum, and the experimental results reported by others. We review the conflicting published treatments of this problem, some of which have been incorrect and many of which have introduced complications that obscure the basic physics involved."