And most importantly, don’t forget to join us MARCH 13, at 1pm for the PLUTO IS A PLANET PROTEST MARCH AND RALLY. The march starts at the Greenwood Space Travel Supply store (8414 Greenwood Ave N) and will end at Neptune Coffee (8415 Greenwood Ave N).

But really, Greenwood Space Travel Supply is all kinds of awesome, even if they’re weirdly co-dependent with small rocks in the outer solar system. They’re the Seattle branch of the 826 network, which is a non-profit writing center for kids.

They also have cool t-shirts.

Monday morning I talked on the phone with Emily Lazar, a researcher for the show. I was really impressed right from the start: it was clear that she wanted to make it easy for me to get across some substantive message, within the relatively confining parameters of what is basically a comedy show. From start to finish everyone I dealt with was a consummate pro.

We got picked up at our hotel in a car that brought us to the Colbert studio, and hustled inside under relatively high security — people whispering into lapel microphones that we had arrived and were headed to the green room. Very exciting. The green room was actually green, which is apparently unusual. I got pep talks from a couple of the staff people, who encouraged me to keep things as simple as possible. They made an interesting point about scientists: they make the perfect foils for Stephen’s character, since they actually rely on facts rather than opinions.

Stephen himself dropped by to say hi, and to explain the philosophy of his character — I suppose there still are people out there who could be guests on the show who haven’t ever actually watched it. Namely, he’s a complete idiot, and it’s my job to educate him. But it’s not my job to be funny — that’s his bailiwick. The guests are encouraged to be friendly and sincere, but not pretend to be comedians.

We got to sit in the audience as the early segments were taped, which were hilarious. I feel bad that my own interview is going to be the low point of the show, laughs-wise. But I went out on cue, and fortunately I wasn’t at all jittery — too much going on to have time to get nervous, I suppose.

I had some planned responses for what I thought were the most obvious questions. Of which, he asked zero. Right off the bat Colbert managed to catch me off guard by asking a much more subtle question than I had anticipated — isn’t the early universe actually very disorderly? That would be true if you ignored gravity, but a big part of my message is that you can’t ignore gravity! The problem was, I had promised myself that I wouldn’t use the word “entropy,” resisting the temptation to lapse into jargon. But he had immediately pinpointed an example where the association of “low entropy” with “orderly” wasn’t a perfect fit. So I had to go back on my pledge and bring up entropy, although I didn’t exactly give a careful definition.

As everyone warned me, the whole interview went by in an absolute flash, although it really lasts about five minutes. There was a fun moment when we agreed that “Wrong Turn Into Yesterday” would make a great title for a progressive-rock album. Overall, I think I could have done a better job at explaining the underlying science, but at least I hope I successfully conveyed the spirit of the endeavor. We’ll have to see how it comes across on TV.

I shouldn’t end without including some good words about the bag of swag. Not only does every guest get a goodie bag that includes a bottle of excellent tequila, it also includes a $100 gift certificate for Donors Choose. How awesome is that?

And as we left the studio, there were some young audience members lurking around hoping for a glimpse of the great man himself. They had to settle for me, but they sheepishly asked if I would pose for a picture with them. Not yet having perfected my diva act, I happily complied. I hope they take away some great memories of the night.

Yesterday’s book club post referred to a somewhat-whimsical vision of Maxwell’s Demon as a paradigm for life. The Demon takes in free energy and uses it to maintain a separation between hot and cold sides of a box of gas — a sustained departure from thermal equilibrium. But what if we reversed the story? Instead of thinking that the Demon takes advantage free energy to help advance its nefarious anti-thermodynamic agenda, what if we imagine that the free energy is simply using the Demon — that is, the out-of-equilibrium configurations labeled “life” — for its own pro-thermodynamic purposes?

Energy is conserved, if we put aside some subtleties associated with general relativity. But there’s useful energy, and useless energy. When you burn gasoline in your car engine, the amount of energy doesn’t really change; some of it gets converted into the motion of your car, while some gets dissipated into useless forms such as noise, heat, and exhaust, increasing entropy along the way. That’s why it’s helpful to invent the concept of “free energy” to keep track of how much energy is actually available for doing useful work, like accelerating a car. Roughly speaking, the free energy is the total energy minus entropy times temperature, so free energy is used up as entropy increases.

Because the Second Law of Thermodynamics tells us that entropy increases, the history of the universe is the story of dissipation of free energy. Energy wants to be converted from useful forms to useless forms. But it might not happen automatically; sometimes a configuration with excess free energy can last a long time before something comes along to nudge it into a higher-entropy form. Gasoline and oxygen are a combustible mixture, but you still need a spark to set the fire.

This is where life comes in, at least according to one view. Apparently (I’m certainly not an expert in this stuff) there are two competing theories that attempt to explain the first steps taken toward life on Earth. One is a “replicator-first” picture, in which the key jump from chemistry to life was taken by a molecule such as RNA that was able to reproduce itself, passing information on to subsequent generations. The competitor is a “metabolism-first” picture, where the important step was a set of interactions that helped release free energy in the atmosphere of the young Earth. You can read some background about these two options in this profile of Mike Russell (pdf), one of the leading advocates of the metabolism-first view.

I was reading a bit about this stuff because I wanted to move beyond the fairly simplistic sketch I presented in my book about the relationship between entropy and life. So I did a little research and found some papers by Eric Smith at the Santa Fe Institute. Smith has taken quite an academic path; his Ph.D. was in string theory, working with Joe Polchinski, and now he applies ideas from complexity to questions as diverse as economics and the origin of life.

On Saturday I was on a long plane ride from LA to Bozeman, Montana, via Denver. So I had pulled out one of Smith’s papers and started to read it. A couple sat down next to me, and the husband said “Oh yes, Eric Smith. I know his work well.” This well-read person turned out to be none other than Mike Russell, featured in the profile above. Here I was trying to learn about entropy and the origin of life, and one of the world’s experts sits down right next to me. (Not completely a coincidence; Russell is at JPL, and we were both headed to give plenary talks at the annual IEEE Aerospace Conference.)

So I explained a little to Mike (now we are buddies) what I was trying to understand, and he immediately said “Ah, that’s easy. The purpose of life is to hydrogenate carbon dioxide.” (See figure above, taken from one of Eric Smith’s talks.)

That might be something of a colorful exaggeration, but there’s something fascinating and provocative behind the idea. An extremely simplified version of the story is that the Earth was quite a bit hotter in its early days than it is today, and the atmosphere was full of carbon dioxide. At high temperatures that’s a stable situation; but once the Earth cools, it would be energetically favorable for that CO₂ to react with hydrogen to make methane (and other hydrocarbons) and water. That is to say, there is a lot of free energy in that CO₂, just waiting to be released.

The problem is that there is a chemical barrier to actually releasing the energy. In physicist-speak: the Earth’s atmosphere was caught in a false vacuum. There’s no reaction that takes you directly from CO₂ and hydrogen to methane (CH₄) and water; you have to go through a series of reactions to get there. And the first steps along the way constitute a potential barrier: they consume energy rather than releasing it. Here’s a plot from one of Russell’s talks of the free energy per carbon atom of various steps along the way; it looks for all the world like a particle physicist’s plot of the potential energy of a field caught in a metastable vacuum. (Different curves represent different environments.)

Here is the bold hypothesis: life is Nature’s way of opening up a chemical channel to release all of that free energy bottled up in carbon dioxide in the atmosphere of the young Earth. My own understanding gets a little fuzzy at this point, but the basic idea seems intelligible. While there is no simple reaction that takes CO₂ directly to hydrocarbons, there are complicated series of reactions that do so. Some sort of membrane (e.g. a cell wall) helps to segregate out the relevant chemicals; various inorganic compounds act as enzymes to speed the reactions along. The reason for the complexity of life, which is low entropy considered all by itself, is that it helps the bigger picture increase in entropy.

In ordinary statistical mechanics, we say that high-entropy configurations are more likely than low-entropy ones because there are simply more of them. But that logic doesn’t quite go through if you can’t get to the high-entropy configurations in any straightforward way. Nevertheless, a sufficiently complicated system can bounce around in configuration space, trying various different possibilities, until it hits on something that looks quite complex and unlikely, but is in fact very useful in helping the system as a whole evolve to a higher-entropy state. That’s life (as it were). It’s not so different from other cases like hurricanes or turbulence where apparent complexity arises in the natural course of events; it’s all about using up that free energy.

Obviously there is a lot missing to this story, and much of it is an absence of complete understanding on my part, although some of it is that we simply don’t know everything about life as yet. For one thing, even if you are a metabolism-first sympathizer, at some point you have to explain the origin of replication and information processing, which plays a crucial role how we think about life. For another, it’s a long road from explaining the origin of life to getting to the present day. It’s true that we know of very primitive organisms whose goal in life seems to be the conversion of CO₂ into methane and acetate — methanogens and acetogens, respectively. But animals tend to produce CO₂ rather than consume it, so it’s obviously not the whole story.

No surprise, really; whatever the story of life might be, there’s no question it’s a complicated one. But it all comes down to the elementary building blocks of Nature doing their best to fulfill the Second Law.

Excerpt:

Schrödinger’s idea captures something important about what distinguishes life from non-life. In the back of his mind, he was certainly thinking of Clausius’s version of the Second Law: objects in thermal contact evolve toward a common temperature (thermal equilibrium). If we put an ice cube in a glass of warm water, the ice cube melts fairly quickly. Even if the two objects are made of very different substances—say, if we put a plastic “ice cube” in a glass of water—they will still come to the same temperature. More generally, nonliving physical objects tend to wind down and come to rest. A rock may roll down a hill during an avalanche, but before too long it will reach the bottom, dissipate energy through the creation of noise and heat, and come to a complete halt before very long.

Schrödinger’s point is simply that, for living organisms, this process of coming to rest can take much longer, or even be put off indefinitely. Imagine that, instead of an ice cube, we put a goldfish into our glass of water. Unlike the ice cube (whether water or plastic), the goldfish will not simply equilibrate with the water—at least, not within a few minutes or even hours. It will stay alive, doing something, swimming, exchanging material with its environment. If it’s put into a lake or a fish tank where food is available, it will keep going for much longer.

This chapter starts with something very important: the relationship between entropy and memory. Namely, the reason why we can “remember” the past and not the future is that the past features a low-entropy boundary condition, while the future does not. I don’t go into great detail about this, and we certainly don’t talk very specifically about how real memories are formed in the brain, or even in a computer. But when we get to the next chapter, about recurrences and Boltzmann brains, it will be crucial to understand how the assumption of a low-entropy boundary condition enables us to reconstruct the past. It’s hard for people to wrap their brains around the fact that, without such an assumption, our “memories” or records of the past will generally be unreliable — knowledge of the current macrostate wouldn’t allow us to reconstruct the past any better than it allows us to predict the future. (Which is only logical, since it’s only this hypothesis that breaks time-reversal symmetry.)

The rest of the chapter, meanwhile, is more about having fun and mentioning some ideas that are not directly related to our story, but certainly play a part in understanding the arrow of time. Information theory, life, complexity. I’m not an expert in any of these fields, but it was a lot of fun reading about them to pick out some things that fit into the broader narrative. The Maxwell’s Demon story, in particular, is one that every physicist should know (up through it’s relatively modern resolution), but relatively few do. And I think Jason Torchinsky did a great job with the illustrations of the Demon.

A lot of big ideas here, of course, and much of this stuff is still very much in the working-out stage, not the settled-understanding stage. We’re still arguing about basic things like the definition of “complexity” and “life.” It’s relatively easy to state the Second Law and explain how the arrow of time is related to the growth of entropy, but there’s a tremendous amount of work still to be done before we completely understand the way in which the universe actually evolves from low entropy to high.

Of course, I’m talking about Alice in Wonderland. What, is there some other movie you were thinking of? Spoilers follow (although it’s not the type of movie that gets spoiled), so if you’re hyper-sensitive about such things (as I am), cease reading now.

Alice and Avatar make an excellent study in contrasts. They both use the same canvas, and there are remarkable superficial similarities between the two. However, I found Alice to be much more interesting and satisfying as a film. Avatar, as the entire world seems to have noted, has a completely mundane and predictable story, with a sound-byte message. Within about ten minutes of the film, you know more-or-less the full arc. It’s a reasonable story, with lots of visual candy, and I can’t say I was bored (which is saying a lot for a three hour film). But, at least for me, it left little mark. To go to such great lengths to build up an entire world, you’d think you’d have something profoundly new and interesting to say. Sean does a nice job of summarizing some of Avatar’s failings.

I found Alice, on the other hand, to be much more entertaining. For any self-respecting science geek, having a movie which revolves around a vorpal sword has to warm the cockles of your heart. But there’s substance behind all of the talking flowers and Jabberwocks. For example, consider the good and bad queens. They had interesting, quirky personalities, and didn’t play directly to stereotype. In Avatar, these roles would have been completely one dimensional. In Alice, the Red Queen has moments of doubt, and seems genuinely surprised that she is not loved. Images of hearts proliferate, to no avail. The White Queen, meanwhile, swats at “dragonflies” while professing her love for all creatures. She seems somewhat annoyed that she’s not allowed to wreak mayhem on her rival, as if she’s struggling within the bounds of the “good queen” convention. There are subtle physical manifestations as well: her snow white hair is dark underneath, and she has slightly dark circles about her eyes. The distance between the two queens (and sisters) is not as great as it initially appears. These satisfying levels of grey give the characters more depth and nuance (something that is completely absent in Avatar). Alice demands that the viewer do some work; the movie does not present everything neatly wrapped with a bow. The moral of the film is left a bit hazy. It has something to do with letting your imagination run wild. Resisting convention. Living in the world you want, rather than the one you find. At the end of Avatar, the main character remains on Pandora. Alice, on the other hand, chooses to leave Wonderland and return to London. Which film is more courageous?

The list of blogs chosen is — okay, I guess. I have no idea how it was constructed, and the paper doesn’t seem to provide much guidance. Bora has a critique of the methodology that wonders about that, and about exactly how objective the study is. It’s very hard to assign numbers to things like “ratio of informative posts vs. rants,” or “degree to which the cause of collegial communication was harmed by use of intemperate language.” The paper reads like someone read a bunch of blogs and typed up their personal impressions.

For the most part I don’t disagree too strongly with the impressions, with the obvious caveat that it’s almost completely useless to study “science blogs” as a group. People don’t read randomly chosen collections of blogs; they read very intentionally chosen subsets that appeal to their own interests, and different reading lists will lead to wildly divergent impressions about what blogs are really like.

More significantly, though, I can’t really agree with the moral that the author draws from these experiences. Here is the telling quote from the paper:

The blogs employ a variety of writing and authoring models, and no signs of emerging or stabilizing genre conventions could be observed. Even though all blogs mentioned science or a particular scientific discipline in their descriptions, they differed in their voice representations, points of view, and content orientation.

It’s hard to disagree with that, but I think it’s a good thing, and the author clearly does not. Blogs differ in many ways, and happily avoid the encroachment of stabilizing genre conventions. That’s one of the biggest benefits of opening up communication channels to a tremendous variety of content providers, rather than restricting things to just a few mainstream outlets; writers can have their voices, and readers can choose who to read, and everyone is happy.

It’s clear that a lot of people want blogs to be just like some pre-existing communication medium, just with comments and occasional expertise. And there are blogs like that, if that’s what you’re into. And there are blogs that aren’t, likewise. I hope it stays that way.

For the uninitiated: imagine an oversized longboard (over 10 feet long), with extra width and stability. You stand up on the board, and use a long-handled paddle to propel yourself through the water. Sort of like a canoe, only standing up. It’s good exercise. It’s also really fun. You can really cruise. And you can enjoy it even if it’s totally flat (although the real fun is to take the big boards into the surf).

The rapid rise in popularity is almost certainly due to the fact that the learning curve for stand-up paddleboarding is shallow. The average person can be up and going in about 10 minutes. And it’s almost like they’re surfing. After all, they’re standing on a surfboard, moving through the water. However, this is a pale imitation. Until you actually get the board out in the surf, and feel the acceleration of a drop, and the exhilaration as you glide down a wall of water, you have no idea what it’s all about. Good paddleboarders can go out in big surf. But that part of the learning curve is Jaws steep.

I was in Maui this past January, and my favorite break (Kanaha) was overrun by paddleboards. At least half the people out there were doing stand-up. For a “conventional” surfer it’s a bummer, since the paddleboards catch waves early, and there’s no room to drop in, even if you wanted to. But if you can’t beat ‘em….

About a year ago I had my initiation, doing a down-winder from past Ho’okipa to Spreckelsville. It took a while to get the balance down, but eventually you figure out where to stand, and how to use the paddle for stability. And then you’re cruising. You can paddle into reasonable breaking surf, since the board has a tendency to keep going and remain unperturbed. You cut right through waves that would have tossed a longboard. However, I can tell you from painful experience that it really sucks to get Maytagged while doing stand-up. I have a nice fin-shaped scar to prove it.

Let’s assume that the buses are supposed to arrive every 15 minutes. If the buses adhered to their schedule, and I showed up at a random time, I should generally have to wait roughly half the mean bus arrival time: 7.5 minutes. If the buses were totally random, then I would have to wait the average time between bus arrivals: 15 minutes (if you haven’t thought about this before, this statement should sound crazy; perhaps I’ll do a future post on it). So the question is: why did I always end up waiting roughly 30 minutes or more?

I always assumed that the Universe was conspiring against me. This is a common feeling in graduate school. However….

I just stumbled across a blog post of a friend of mine from graduate school, Alex Lobkovsky. In it, he discusses precisely this problem, and presents various reasons for the bunching of buses. I have no doubt that he was inspired from similar suffering. Perhaps at the very same bus stop.

At the end of the day, there’s a fairly straightforward solution. Imagine all of the buses are roughly on time. Now imagine that one bus (call it bus S) happens to fall behind. Because S is running behind, more time has elapsed since the previous bus has passed. This means that more waiting passengers have accumulated, at more bus stops. This in turn means that bus S has to stop more often, and has to pick up more people at each stop. Hence, bus S falls even farther behind. Which means even more people accumulate at each stop. Which means the bus falls even farther behind. And so on. In short: a slow bus gets slower and slower.

Now let us consider the bus behind bus S; we’ll call it bus F. Bus F starts out roughly on schedule. But because bus S is running late, less time than average has elapsed between when bus S last passed and when bus F arrives. This means fewer people have accumulated, at fewer stops. Which means bus F makes fewer stops, and picks up fewer people. Which means that it starts to run faster than average. Which means even fewer people accumulate. Which means it runs even faster. And so on. In short: a fast bus gets faster and faster.

Putting this all together: if a random fluctuation creates a slow bus, then it will get slower and slower, and the bus behind it will get faster and faster, until the two buses meet up. At this point, the buses stick together, and are essentially incapable of separating. Thus, in general, buses will bunch up. This will usually happen in pairs, though on occasion triples and even quads may occur. This argument predicts that the arrival of buses will be random, with pairs of buses arriving more often than not, being separated by on average double the mean bus separation. And this is precisely what I discovered, the hard way, shivering at the corner of 55th St. and Hyde Park Boulevard. (N.B. I spent a year in Berlin. There, the buses are fermions, and always arrive exactly on time. It’s the stereotype, but it turns out to be true.)

After writing this post, I found that wikipedia has already figured it all out. Regardless, it’s nice to know that my suffering was due to statistics, and not because the Universe is out to get me.

Small scheduling glitches aside, the Colbert Report and the Daily Show remain two of the best places to hear interviews with interesting academics on TV, especially with scientists. In USA Today, Dan Vergano writes about this curious state of affairs. Neil deGrasse Tyson brings up a good point, that Johnny Carson’s version of the Tonight Show used to feature interviews with heavyweights such as Carl Sagan and Margaret Mead. These days, not many non-satirical network news shows bring on scientists (or anthropologists, or for that matter philosophers or English professors) as a regular event.

When Conan O’Brian took over the Tonight Show, the Science and Entertainment Exchange received a request from the producers to suggest some entertaining (and hopefully enlightening) scientists they could consider bringing on as guests. I don’t know if they ever followed up on that idea, and now I guess we’ll never know. Hopefully the success of Stewart and Colbert will convince the networks that Americans don’t necessarily turn the channel when faced with people who think carefully about the universe.

The term “hella” is one I first heard my sister-in-law utter in the context “that ski run was hella fun!”, which I immediately took as a shorthand for “a hell of a lot of”. I’ve since learned that it originated, reportedly, in San Francisco to mean just that, or “very” in general, as in “that tee shirt is hella awesome” – it’s not an uncommon utterance to hear here in northern California.

And, 10²⁷ is hella big, to be sure. A hellasecond is ten billion times the age of the universe, and the mass of the earth is about 6 hellagrams.

It seems that hella is poised to go viral…there are nearly 24,000 fans of the facebook petition, and it even made the local news last night in Sacramento.

Who decides such things? The International Bureau of Weights and Measures, that’s who. They added yotta in 1991. Sign the petition to them at the facebook site!