The enigmatic title isn’t anything I can explain right now; it is the title of the talk I’m supposed to give at the conference in Tuscon at which I just arrived. A collection of cosmologists at a golf resort in the desert; who thinks of these things? The talk is tomorrow morning, and it’s not written yet, so no substantive posting today.

Instead, read Michael Bérubé’s ideas about conferences. Spit-takes and electric shocks are involved, so you won’t be wasting your time.

Tomorrow (Weds) I’ll be a guest on Odyssey, a syndicated program from WBEZ, Chicago’s public radio station. We’re supposed to be talking about the “early universe”; of course, what’s early to one person may be pretty late to another. I think we’ll be covering a lot of ground, from 10^(-35) seconds (inflation) through one minute (nucleosynthesis) and 400,000 years (the cosmic microwave background) up to 500 million years (the earliest galaxies). The other guest will be Bob Kirshner from Harvard, a supernova expert and one of the co-discoverers of dark energy. Bob is an engaging speaker and a great scientist; I reviewed his popular-level book for Nature, and we managed to remain friends.

If your local public radio station doesn’t get Odyssey, you can easily listen on the web. (I’ve been on a few times before, the shows are available in the archive.) But even better, you should call your local station and demand they get the program. It’s an hour-long discussion, typically with two or three guests, about every sort of topic you can think of, with a decided emphasis on high-level (but accessible) intelligent discourse. The host, the glamorous and charming Gretchen Helfrich, does an amazing job of keeping the dialogue lucid and amusing no matter what the topic is.

[Update: here’s the audio. The metaphor of the moment was that of a movie in which the first reel is mostly missing except for a few frames. Personally, given that our universe is pretty clever, but prone to violence and self-indulgence, I’m thinking it’s a Tarantino film.]

Grading papers right now for our Moments in Atheism class. I figured that I would learn a lot from reading these (at least the good ones), and it’s true. One of the students (Nicholas Boterf) found a wonderful quote in Juliette, a 1797 novel by the Marquis de Sade. Juliette is somewhat scandalized by the implications of what her “tutor,” Madame Delbene, has been telling her:

“But … if there be neither God nor religion, what is it runs the universe?”

“My dear,” Madame Delbene replied, “the universe runs itself, and the eternal laws inherent in Nature suffice, without any first cause or prime mover, to produce all that is and all that we know.”

I tend not to go along with some of the Marquis’ ethical deductions from the godlessness of the world, but he got it exactly right with that quote.

For me, one of the rewards from looking at the history of these ideas was a better understanding of the change in perspective between Aristotelian mechanics and Galileo/Newton. Only now does it make sense why anyone would think the “first cause” arguments (Aristotle, Aquinas, etc.) held any weight at all. Aristotle thought that, to keep an object moving in a straight line, you had to keep pushing it. This seems silly to us post-Newtonians, but in fact it’s pretty straightforward. Take a chair sitting on the floor and give it a push — once you stop pushing, it will stop moving. “Aha,” you say, “but that’s only because of friction. If we ignore the friction, objects continue to move in straight lines unless forces act upon them.” True, but highly non-intuitive. Why should we ignore friction, when it is ubiquitous in the real world abound us? Aristotle wasn’t making a mistake, he was accurately describing the world he saw. If we take his description seriously, it’s not so crazy to argue all the way to God. Lots of things in the world are moving, and moving objects require something to keep them moving, and ultimately that thing will be God.

Galileo’s insight — that the way to describe dynamics is to ignore friction and air resistance, find a simple model for the resulting motions, and then re-introduce friction afterwards — was one of the most important moments in the history of science, and indirectly of religion as well. After he and Newton figured out conservation of momentum and the laws of motion, the Aristotle/Aquinas line of argument suddenly makes no sense. We don’t need a “cause” or “mover” to explain why things are moving; that’s the natural thing for them to do. This Newtonian revolution was, at a purely intellectual level, just as important as the Darwinian revolution for taking the philosophical wind out of religion’s sails. After Newton, the primary justification for God shifted from cosmological arguments about first causes, to design arguments. Then Darwin made those seem silly (although Hume had done a pretty convincing job years before).

Have we discovered a new planet in the outer regions of the solar system? NASA seems to think so. Two orbiting telescopes — the Hubble Space Telescope, about which we’ve been ranting previously, and the Spitzer Space Telescope, a relatively new infrared observatory named after my Ph.D. advisor’s Ph.D. advisor — have both seen evidence for a relatively large new object. It might be as big as Pluto. Deciding that the Roman pantheon has become politically incorrect, the new object has been named “Sedna,” after the Inuit goddess of the ocean.

This is fun, but not an earth-shaking (as it were) discovery, to be honest. There’s likely to be all sorts of medium-sized rocky objects lurking in the far-flung regions of the Sun’s orbit. And the debate about whether Pluto is really a planet was boring and silly. Probably there is an advanced civilization floating deep in the atmosphere of Jupiter, that spends coffee breaks arguing whether Mercury, Venus, Earth and Mars should be classified as planets. (Okay, not “probably.”) But the relentless series of new discoveries has to make the Hubble-killers uncomfortable.

NASA Administrator Sean O’Keefe’s decision to cancel future servicing missions to the Hubble Space Telescope has been met with an outcry from scientists, politicians, and ordinary people all over the world. It’s been very difficult to figure out what O’Keefe’s response really is. On the one hand, he has agreed to request a new National Academy of Sciences report that would study the pros and cons of future servicing missions. On the other, he continues to say (for example in today’s New York Times) that he won’t authorize a new Shuttle mission that is inconsistent with the guidelines set forth by the Columbia Accident Investigation Board — which an HST servicing mission would be, since there is currently no way for a Shuttle crew visiting HST to inspect the orbiter for damage.

Safety is the most common argument against future servicing missions — fortunately for those of us who favor new missions, it’s a completely ridiculous argument. True, manned missions to space are dangerous, no matter what precautions we take. But does anyone in their right mind think that a visit to HST is more dangerous than a trip to Mars? The astronauts who comprise shuttle crews understand the risks, and would be more than eager to get the chance to upgrade Hubble. The only real argument is about money.

Which is completely ludicrous, since the budget includes a hefty chunk of change for future missions and upgrades to the International Space Station. The ISS has been a sad boondoggle from start to finish, a laughingstock in the scientific community. A combination of international obligations and a politically-astute dispersion of ISS contracts throughout multiple congressional districts make this beast impossible to kill. Apparently the Administration’s plan is to spend a huge amount of money finish building it (just barely), and then declare victory (“Mission Accomplished”?) and let it rot up in orbit.

Meanwhile, clever folks at NASA are examining all sorts of imaginative proposals for servicing Hubble robotically, without a manned mission. These guys are good, and it may be possible to keep the observatory orbiting and operating for longer than its current expected lifespan of 3-4 years. But it’s nearly impossible to imagine upgrading the telescope with the new instruments that have already been built. Regardless of this effort, it’s absolutely worthwhile to keep pushing for another servicing mission to HST.

(I suppose posts like this don’t help my chances for future NASA funding very much.)

Related: Ultra Deep Field.

Donald Rumsfeld was apparently very fastidious when he first toured the Pentagon after 9/11; enough that he walked away with a piece of the crashed airplane as a souvenir. (Original link from Fark.com.) He keeps it on his desk, and shows it to visitors as a reminder of the tragedy. Which, I guess, might otherwise just slip his mind completely.

That last post I put up was in a hurry (catching a plane back to Chicago), and it didn’t quite form the crystalline structure of unassailable logic that, you know, all the other posts do. So let me elaborate a little. (I could just go back and edit the thing, nobody would know; the technology lets me, but it seems like cheating. I bet Robert Novak wishes he could do that.)

First, why the ad is bad: not because it suggests that the terrorists responsible for the 9/11 attacks were Arabs, but because it appeals to irrational fears rather than making a reasonable argument for certain policy choices. (Probably “xenophobic” would have been a better adjective to use than “racist” in the original post.) It’s an emotional cheap shot; those are trite but unobjectionable when they are sugary and uplifting (“Morning in America”), but odious and inexcusable when they appeal to our less-lofty sides.

Second, is it a good campaign strategy? I really don’t know. But it does seem to be a little early to be stooping that low. As I understand the conventional wisdom, a negative attack (such as this obviously is) may initially be effective, but over time can lead to backlash. So in the last few weeks of a campaign, they can be quite useful, but at this early stage Bush is going to take so much grief from the ad that it hardly seems worth whatever benefit he might get. Another good question I don’t know the answer to: of the people an ad like this might hope to influence (swing voters who actually haven’t made up their minds, and mildly-apathetic folks who need to be prodded to vote), how many will see the ad but not hear the accompanying media commentary, and how many will get the commentary without the ad? I’m sure the pros have calibrated this backwards and forwards. (Right?)

Ever since Homicide went off the air, my TV viewing is largely limited to NBA games, Queer Eye, and occasionally the Iron Chef. So I don’t get to see a lot of the new campaign ads. Blogosphere to the rescue, however, as we can easily dissect every new ad without ever reaching for the TV remote.

The latest Bush ad takes a step that nobody should find surprising, but some find upsetting: using an image of an olive-skinned, vaguely Arabic-looking man to symbolize the threat of terrorism. (The ad is discussed, with screenshots, by Ryan Lizza at TNR and Billmon at Whiskey Bar.)

Bush supporters can say (and already are saying, e.g. at Little Green Footballs) that this is no big deal — after all, the Sept. 11 terrorists were olive-skinned Arabs. This is a true statement, just as it is true to say that the DC snipers were African-American, or that Timothy McVeigh, the Unabomber, and Jack the Ripper were all Caucasian. Under the hypothesis that all statements of fact are equally appropriate, I suppose there’s nothing more to say. But this is a blatantly racist appeal: Bush will protect us from the scary Arabs. Not only is it repulsive, it’s also not a sensible long-term strategy for fighting terrorism (which comes in all colors, as folks in Ulster will tell you). But who knows, maybe it will work as a campaign theme.

Atrios points to this post from Poor Man, reconstructing the ad the Bush campaign would really like to have made, if the liberal media would let them get away with it.

I’m visiting the Perimeter Institute, a swanky Canadian center for theoretical physics. They’re open to speculative ideas here, so I gave a talk yesterday about the arrow of time.

The celebrated Second Law of Thermodynamics tells us that entropy, a measure of the disorder in a system, tends to increase with time (unless some outside influence acts to increase the order). The first person to understand this phenomenon was Ludwig Boltzmann (who later committed suicide). Boltzmann realized that the entropy was a measure of how many ways a system could be arranged that were basically indistinguishable. For example, if we have some gas distributed uniformly throughout a box, we can move individual atoms around in many different ways without affecting basic features like the density and pressure; so a uniform gas has a high entropy. But if all the gas is squeezed into one corner, there are fewer rearrangements that leave the system basically unchanged, so the entropy is lower. We therefore expect that gas can easily spread from a single corner to fill the box, but it’s very unlikely that uniform gas will suddenly congregate in one tiny region. Thank goodness, or breathing would be a constant adventure.

But Boltzmann also realized the major unsolved problem: entropy only increases because it was very low in the past. Why did the universe start out that way? We still don’t really know the answer. In my talk I proposed an answer, that I’ve been working out with Jennifer Chen. We make the very simple suggestion that the entropy is increasing because it can always increase — in the real universe, there is simply no state of maximum entropy. So the fact that the entropy is going up is very natural, since it can always do that. The crucial ingredient we use is the idea of eternal inflation. “Inflation” is the idea that a tiny region of space can expand at a super-accelerated rate, growing into a size much larger than our entire observable universe. Eventually this process ends in most places, and the inflating universe converts into a more conventional Big-Bang cosmology; but “eternal” implies that it never ends everywhere, there’s always some region far outside what we can observe where inflation is still going on. This process of inflation both constantly generates more and more entropy, and creates large regions that look just like our observed universe in the process.

The title of the post refers to the fact that memory relies crucially on the second law of thermodynamics. Why do we remember the past and not the future? Because, as entropy increases, we develop correlations between the external universe and our brains; if our universe was in a state of maximum entropy (thermodynamic equilibrium), we wouldn’t be able to remember the past or the future. (We wouldn’t really exist as complex organisms, for that matter; thank the universe for small favors.)

The Hubble Space Telescope, in a spiteful attempt to make NASA look silly for canceling future servicing missions, continues to crank out wonderful new results.

This is a detail from the new Ultra Deep Field. They point the telescope at one small region of the sky and just let it sit there, gradually collecting the tiny number of photons that are coming to us from these galaxies in the early universe. The objects seen here formed approximately 500 million years after the Big Bang; in a 14 billion year old universe, that’s pretty young. Besides being a pretty picture, images like this help astrophysicists to figure out the processes by which galaxies became assembled out of the nearly-uniform plasma of the earliest times.