Hola, mis amigos! Jen-Luc Piquant and I have returned from our South American sojourn, well-rested, and a bit too well-fed, thanks to great, cheap food and those tasty little alfajores -- dulce de leche sandwiched between wafer cookies -- that one can purchase on practically every street corner. (Argentines are diehard meat and potatoes and pastry people; we barely saw any fresh vegetables at all during our stay, save for some wilted iceberg lettuce and one pale excuse for a tomato, together gamely attempting to masquerade as a "salad.") Mega-kudos to guest-blogger Lee Kottner for filling in so ably and eloquently in our absence; she'll be posting at least once more in the future with an update on the space elevator story, so sci-fi fans, stay tuned.
We are, needless to say, a bit out of touch with what's been going on the last 10 days in the dear old U.S. of A. (The first thing that caught Jen-Luc's gourmand eye this morning is the news that scientists have created a hybrid form of chocolate that won't melt to a sticky goo in the heat.) Among other things, Internet access was sporadic at best: once a day we repaired to the corner locutorio to use one of the public broadband connections, and there really wasn't much time for leisurely perusal of our usual feeds.
But that's okay. Because there's something about being in a foreign country that shifts one's perspective -- in a good way. We all need to view things from a different angle now and then, intellectually, emotionally, and physically. A trip to a different hemisphere can be just the ticket. It reminds me of a scene in one of my all-time favorite films, Grosse Pointe Blank, in which John Cusack's amoral (but reforming) hitman is having drinks with the lost love of his life, former high school prom date Debi. "You know what you need?" she tells him. "Shakabuku." She describes it as "a swift, spiritual kick to the head that alters your reality forever."
I was reminded of shakabuku while perusing a tome of deep profundity on my vacation: Huw Price's Time's Arrow and Archimedes' Point. (Yes, we know it's hardly light summer reading; blame it on Jen-Luc's pernicious influence. Left to my own devices, I mostly read about pirates.) Price is a philosopher by trade, with an abiding interest in physics, and in this instance he tackles the problem of entropy and time's arrow -- why time only moves forward into the future, not backward into the past, in our everyday reality, even though mathematically, there is no such distinction between past and present -- from the perspective of philosophy. The entire book essentially deals with how scientists can be limited by their constrained perspectives, particularly when it comes to the knotty problem of time, and emphasizes how useful it can be to look at familiar subjects from a new vantage point. (For all his redundancy and tangled "academese" -- which makes for a rather labored prose style -- Price is not lacking a sense of humor; his preface opens with a quote from Groucho Marx: "Time flies like an arrow; fruit flies like a banana.")
Archimedes, you may recall, was a natural philosopher (a.k.a., early scientist) in ancient Greece who famously offered to move the Earth, provided someone would supply him not just with a big enough lever, but a broader perspective -- a vantage point outside his earth-bound reality from which he could, for instance, view both a pebble and the earth as exactly the same kind of thing, "differing only in size." Archimedes called this the "view from nowhere."
Price contends that when it comes to time's arrow, physicists need to take a "view from nowhen," being more vigilant about taking their own embedded perceptions about time into account when constructing theories about the universe. Per Price: "We are creatures in time, and this has a very great effect on how we think about time and the temporal aspects of reality.... [I]t is very difficult to distinguish what is an aspect of reality from what is a kind of appearance, or artifact, of the particular perspective from which we regard reality."
Price is the first to point out that this notion of a fresh vantage point is not a new one, in philosophy or science. In fact, that's what often leads to revolutionary breakthroughs -- the most obvious example being the heliocentric (sun-centered) cosmology of Copernicus, which eventually toppled the earth-centric view of the solar system espoused since the days of Ptolemy. Charles Darwin's theory of evolution impelled a similar perspective-shifting breakthrough in biology.
When it comes to entropy and time's arrow, the prevailing modern view dates back to an Austrian physicist named Ludwig Boltzmann. The son of a taxation official, Boltzmann earned his PhD in physics from the University of Vienna under the tutelage of Josef Stefan. He moved around a lot in his academic career, partly due to his mercurial mood swings: he joked that these were due to his being born (in 1844) during the dying hours of a Mardi Gras ball, but there is some evidence that he suffered from what we now call bipolar disorder. He also engaged in numerous intellectual feuds with his fellow scientists, most notably with Ernst Mach.
Boltzmann's doctoral thesis was on the kinetic theory of gases, and this ultimately led to his invention of statistical mechanics, which connected the properties and behavior of individual atoms and molecules with the macro-scale properties and behavior of the substances made of those atoms and molecules -- substances like, say, a gas. Boltzmann is the one who derived, statistically, the second law of thermodynamics, namely, that entropy always increases. We experience this every day: heat cannot flow from a colder to a hotter body; a cup of coffee cools at room temperature, rather than the other way around. Shatter the cup, and it won't miraculously self-assemble, either. That's entropy, the basis for the arrow of time. Entropy also has important ramifications for cosmology: entropy increases because our universe began in a state of extremely low entropy, but physicists still can't explain how that highly unlikely low-entropic state came about to begin with. (We have no deep thoughts on this particular conundrum, having not quite finished Price's rather dense tome -- besides, cosmologists themselves are still trying to puzzle it out.)
Before Boltzmann, entropy was deemed to be an absolute law of physics. But when viewed from a statistical viewpoint, an increase in entropy in any given system is merely the most likely probability. There is a tiny, infinitesimal chance that entropy could decrease in a system. The best analogy is to envision a glass container filled with a gas. Uncork the container, and the atoms and molecules that make up the gas will be released into the atmosphere at large, gradually dissipating among all the other atoms and molecules. It is highly unlikely, statistically speaking, that we could get each and every original molecule of gas back into the container, any more than we could toss a glass of water into the sea and then retrieve the same exact glass of water.
This statistical, probabilistic view is also the basis for a famous 19th century thought experiment by British physicist James Clerk Maxwell, dubbed "Maxwell's Demon." Maxwell envisioned an imaginary microscopic creature able to wring order out of disorder to produce energy, chiefly by making heat flow from a cold substance to a hot one in (apparent) violation of the second law of thermodynamics. The imp guards a small hole in a wall separating two compartments of a gas-filled container, and can open and close a small shutter covering the hole at will. The gas in each compartment begins in a state of statistical equilibrium, with the average speed and temperature of the molecules being roughly the same.
But this equilibrium doesn't last. Whenever the demon sees a fast-moving molecule in the right-hand compartment approach the pinhole, he opens the shutter briefly to let it through the left side, and he does the same to enable slower-moving molecules on the left to enter the right-hand compartment. So over time, the gas on the left gets hotter while that on the right gets colder. (Physics students will recall that this temperature difference creates potential energy, which can be converted into kinetic energy and harnessed to perform "work.") The demon wrings order out of disorder, almost as if time were "flowing" backwards. Maxwell himself insisted it was essentially a trick question: the demon is putting energy into the system, and itself requires energy in order to do so, ergo, entropy is not violated.
This statistical approach was hotly debated among Boltzmann's scientific contemporaries, and these and other clashes took their toll on the physicist's already fragile mental state. In 1906, while vacationing with his wife and daughter near Trieste, Italy, Boltzmann hanged himself while said wife and daughter were out swimming. His equation for entropy adorns his tombstone (pictured at right). There's quite a bit of speculation as to why Boltzmann chose to end his life; it may or may not have been to growing depression over the non-acceptance of his ideas by the scientific establishment. If so, his despair was premature. Boltzmann's statistical approach to thermodynamics gave birth to quantum physics, thanks to the work of Max Planck in 1900 on black body radiation.
In physics, a "black body" isn't necessarily black -- it's just a term to describe an object that is a perfect emitter and absorber of electromagnetic radiation. When German scientists first studied the problem experimentally around 1900, they expected that as the temperature of the object rose, the amount of emitted radiation would rise accordingly, essentially into infinity. And this was indeed the case, at least until they hit the ultraviolet regime -- at which point the emitted radiation suddenly began to get smaller and smaller again. They dubbed this the "ultraviolet catastrophe." (The average layperson considers, say, a major earthquake to be an actual catastrophe, but physicists really, really hate it when experiment fails to agree with theory -- it's on a par with being hit with an unexpected tsunami.)
Science historians have dubbed Planck a "reluctant revolutionary," because he initially resisted a statistical approach when grappling with the problem of black body radiation. But it proved to hold the key to solving the riddle, and this new perspective on an old problem gave rise to the notion of quanta: namely that atoms can only absorb or emit radiation energy in little packets of fixed amounts, much like currency only comes in fixed monetary units. We won't go into the specifics of how this solved the problem, except to say that infinity is primarily a mathematical concept; in the real world, there always seems to be a limit or threshold of sorts. Planck's quanta effectively placed a cap on how much the emitted radiation of a black body could increase, and once it hit that threshold, it would start decreasing again -- in keeping with experimental observation. And the quantum revolution ensued. That's the power of shakabuku.
No discussion of scientific shakabuku would be complete without mentioning Albert Einstein. Legend has it that his notion of special relativity -- specifically, that there is no fixed frame of reference -- was inspired by a train trip in his youth. As the train pulled out of the station, he pondered how his experience of motion as a passenger on a moving train would be different from the perspective of someone standing on the platform. Years later, he remembered that experience as he was formulating his theory of special relativity, which (among other things) merges three-dimensional space with a fourth dimension of time. And with general relativity, he brought a fresh perspective to gravity, viewing it as the result of curved spacetime caused by the mass of celestial objects. We simply can't see that curvature from our limited perspective, any more than we can feel the curvature of the earth on a cross-country drive from Washington, DC, to, say, Los Angeles. As far as we're concerned, from our limited perspective creeping along the earth's surface, we're driving in a fairly straight line.
These days, string theory is all the rage, having captured the popular imagination with its notion of even more extra dimensions of space -- nine (or ten, if M theory is your hobby horse) spatial dimensions and one dimension of time. (Offering an alternative fresh perspective, Stephen Hawking has also introduced the notion of a second temporal dimension, dubbed "imaginary time," that essentially runs perpendicular to linear time, giving it a kind of "surface area.") As string theory's growing number of naysayers are fond of pointing out, the problem with this extra-dimensional perspective is that physics has yet to figure out a good way to test the theory, however mathematically impressive it may be. Einstein, for instance, predicted that light would be bent by curved spacetime, and this could be (and was, in 1919) observed during an eclipse. But modern technology has yet to catch up with the mathematical theories of string theory, although some physicists hold out hope of finding evidence of extra dimensions once CERN's Large Hadron Collider is up and running.
Whether or not that turns out to be the case, regardless of whether string theory is proved right or wrong, I think we can safely say that if nothing else, it has served to offer a fresh perspective, which will in turn lead to yet another new vantage point -- and one of these is bound to give rise to yet another unprecedented revolution. It's all about fostering scientific shakabuku. Jen-Luc and I are waiting on tenterhooks to see how it all turns out.