by Sam Kean
“the 2001 Nobel Prize”: The University of Colorado has an excellent Web site dedicated to explaining the Bose-Einstein condensate (BEC), complete with a number of computer animations and interactive tools: http://www.colorado.edu/physics/2000/bec/.
Cornell and Wieman shared their Nobel Prize with Wolfgang Ketterle, a German physicist who also created the BEC not long after Cornell and Wieman and who helped explore its unusual properties.
Unfortunately, Cornell almost lost the chance to enjoy his life as a Nobel Prize winner. A few days before Halloween in 2004, he was hospitalized with the “flu” and an aching shoulder, and he then slipped into a coma. A simple strep infection had metastasized into necrotizing fasciitis, a severe soft tissue infection often referred to as flesh-eating bacteria. Surgeons amputated his left arm and shoulder to halt the infection, but it didn’t work. Cornell remained half-alive for three weeks, until doctors finally stabilized him. He has since made a full recovery.
17. Spheres of Splendor
“to study blinking bubbles full-time”: Putterman wrote about falling in love with sonoluminescence and his professional work on the subject in the February 1995 issue of Scientific American, the May 1998 issue of Physics World, and the August 1999 issue of Physics World.
“bubble science had a strong enough foundation”: One theoretical breakthrough in bubble research ended up playing an interesting role in the 2008 Olympics in China. In 1993, two physicists at Trinity University in Dublin, Robert Phelan and Denis Weaire, figured out a new solution to the “Kelvin problem”: how to create a bubbly foam structure with the least surface area possible. Kelvin had suggested creating a foam of polygonal bubbles, each of which had fourteen sides, but the Irish duo outdid him with a combination of twelve- and fourteen-sided polygons, reducing the surface area by 0.3 percent. For the 2008 Olympics, an architectural firm drew on Phelan and Weaire’s work to create the famous “box of bubbles” swimming venue (known as the Water Cube) in Beijing, which hosted Michael Phelps’s incredible performance in the pool.
And lest we be accused of positive bias, another active area of research these days is “antibubbles.” Instead of being thin spheres of liquid that trap some air (as bubbles are), antibubbles are thin spheres of air that trap some liquid. Naturally, instead of rising, antibubbles sink.
18. Tools of Ridiculous Precision
“calibrate the calibrators”: The first step in requesting a new calibration for a country’s official kilogram is faxing in a form (1) detailing how you will transport your kilogram through airport security and French customs and (2) clarifying whether you want the BIPM to wash it before and after it has done the measurements. Official kilograms are washed in a bath of acetone, the basic ingredient in fingernail polish remover, then patted dry with lint-free cheesecloth. After the initial washing and after each handling, the BIPM team lets the kilogram stabilize for a few days before touching it again. With all the cleaning and measuring cycles, calibration can easily drag on for months.
The United States actually has two platinum-iridium kilograms, K20 and K4, with K20 being the official copy simply because it has been in the United States’ possession longer. The United States also has three all-but-official copies made of stainless steel, two of which NIST acquired within the past few years. (Being stainless steel, they are larger than the dense platinum-iridium cylinders.) Their arrival, coupled with the security headache of flying the cylinders around, explains why Zeina Jabbour isn’t in any hurry to send K20 over to Paris: comparing it to the recently calibrated steel cylinders is almost as good.
Three times in the past century, the BIPM has summoned all the official national kilograms in the world to Paris for a mass calibration, but there are no plans to do so again in the near future.
“those fine adjustments”: To be scrupulous, cesium clocks are based on the hyperfine splitting of electrons. The fine splitting of electrons is like a difference of a halftone, while the hyperfine splitting is like a difference of a quarter tone or even an eighth tone.
These days, cesium clocks remain the world standard, but rubidium clocks have replaced them in most applications because rubidium clocks are smaller and more mobile. In fact, rubidium clocks are often hauled around the world to compare and coordinate time standards in different parts of the world, much like the International Prototype Kilogram.
“numerology”: About the same time that Eddington was working on alpha, the great physicist Paul Dirac first popularized the idea of inconstants. On the atomic level, the electrical attraction between protons and electrons dwarfs the attraction of gravity between them. In fact, the ratio is about 10^40, an unfathomable 10,000 trillion trillion trillion times larger. Dirac also happened to be looking at how quickly electrons zoom across atoms, and he compared that fraction of a nanosecond with the time it takes beams of light to zoom across the entire universe. Lo and behold, the ratio was 10^40.
Predictably, the more Dirac looked for it, the more that ratio popped up: the size of the universe compared to the size of an electron; the mass of the universe compared to the mass of a proton; and so on. (Eddington also once testified that there were approximately 10^40 times 10^40 protons and electrons in the universe—another manifestation.) Overall, Dirac and others became convinced that some unknown law of physics forced those ratios to be the same. The only problem was that some ratios were based on changing numbers, such as the size of the expanding universe. To keep his ratios equal, Dirac hit upon a radical idea—that gravity grew weaker with time. The only plausible way this could happen was if the fundamental gravitational constant, G, had shrunk.
Dirac’s ideas fell apart pretty quickly. Among other flaws that scientists pointed out was that the brightness of stars depends heavily on G, and if G had been much higher in the past, the earth would have no oceans, since the overbright sun would have boiled them away. But Dirac’s search inspired others. At the height of this research, in the 1950s, one scientist even suggested that all fundamental constants were constantly diminishing—which meant the universe wasn’t getting bigger, as commonly thought, but that the earth and human beings were shrinking! Overall, the history of varying constants resembles the history of alchemy: even when there’s real science going on, it’s hard to sift it from the mysticism. Scientists tend to invoke inconstants to explain away whatever cosmological mysteries happen to trouble a particular era, such as the accelerating universe.
“Australian astronomers”: For details about the work of the Australian astronomers, see an article that one of them, John Webb, wrote for the April 2003 issue of Physics World, “Are the Laws of Nature Changing with Time?” I also interviewed a colleague of Webb’s, Mike Murphy, in June 2008.
“a fundamental constant changing”: In other alpha developments, scientists have long wondered why physicists around the world cannot agree on the nuclear decay rates of certain radioactive atoms. The experiments are straightforward, so there’s no reason why different groups should get different answers, yet the discrepancies persist for element after element: silicon, radium, manganese, titanium, cesium, and so on.
In trying to solve this conundrum, scientists in England noted that groups reported different decay rates at different times of the year. The English group then ingeniously suggested that perhaps the fine structure constant varies as the earth revolves around the sun, since the earth is closer to the sun at certain times of the year. There are other possible explanations for why the decay rate would vary periodically, but a varying alpha is one of the more intriguing, and it would be fascinating if alpha really did vary so much even within our own solar system!
“from the beginning”: Paradoxically, one group really rooting for scientists to find evidence for a variable alpha is Christian fundamentalists. If you look at the underlying mathematics, alpha is defined in terms of the speed of light, among other things. Although it’s a little speculative, the odds are that if alpha has changed, the speed of light has changed, too. Now, everyone, including creation
ists, agrees that light from distant stars provides a record, or at least appears to provide a record, of events from billions of years ago. To explain the blatant contradiction between this record and the time line in Genesis, some creationists argue that God created a universe with light already “on the way” to test believers and force them to choose God or science. (They make similar claims about dinosaur bones.) Less draconian creationists have trouble with that idea, since it paints God as deceptive, even cruel. However, if the speed of light had been billions of times larger in the past, the problem would evaporate. God still could have created the earth six thousand years ago, but our ignorance about light and alpha obscured that truth. Suffice it to say, many of the scientists working on variable constants are horrified that their work is being appropriated like this, but among the very few people practicing what might be called “fundamentalist physics,” the study of variable constants is a hot, hot field.
“impish”: There’s a famous picture of Enrico Fermi at a blackboard, with an equation for the definition of alpha, the fine structure constant, appearing behind him. The queer thing about the picture is that Fermi has the equation partly upside down. The actual equation is alpha = e2/hc, where e = the charge of the electron, h = Planck’s constant (h) divided by 2π and c = the speed of light. The equation in the picture reads alpha = h2/ec. It’s not clear whether Fermi made an honest mistake or was having a bit of fun with the photographer.
“Drake originally calculated”: If you want a good look at the Drake Equation, here goes. The number of civilizations in our galaxy that are trying to get in touch with us, N, supposedly equals
N = R* × fP × ne × fl × fi × fc × L
where R* is the rate of star formation in our local galaxy; fP is the fraction of stars that conjure up planets; ne is the average number of suitable home planets per conjuring star; fl, fi, and fc are, respectively, the fractions of hospitable planets with life, intelligent life, and sociable, eager-to-communicate life; and L is the length of time alien races send signals into space before wiping themselves out.
The original numbers Drake ran were as follows: our galaxy produces ten stars per year (R* = 10); half of those stars produce planets (fP = ½); each star with planets has two suitable homes (ne = 2, although our own galaxy has seven or so—Venus, Mars, Earth, and a few moons of Jupiter and Saturn); one of those planets will develop life (fl = 1); 1 percent of those planets will achieve intelligent life (fi = 1/100); 1 percent of those planets will produce post-caveman life capable of beaming signals into space (fc = 1/100); and they will do so for ten thousand years (L = 10,000). Work all that out, and you get ten civilizations trying to communicate with earth.
Opinions about those values differ, sometimes wildly. Duncan Forgan, an astrophysicist at the University of Edinburgh, recently ran a Monte Carlo simulation of the Drake Equation. He fed in random values for each of the variables, then computed the result a few thousand times to find the most probable value. Whereas Drake figured that there were ten civilizations trying to get in touch with us, Forgan calculated a total of 31,574 civilizations just in our local galaxy. The paper is available at http://arxiv.org/abs/0810.2222.
19. Above (and Beyond) the Periodic Table
“one force gains the upper hand, then the other”: The third of the four fundamental forces is the weak nuclear force, which governs how atoms undergo beta decay. It’s a curious fact that francium struggles because the strong nuclear force and the electromagnetic force wrestle inside it, yet the element arbitrates the struggle by appealing to the weak nuclear force.
The fourth fundamental force is gravity. The strong nuclear force is a hundred times stronger than the electromagnetic force, and the electromagnetic force is a hundred billion times stronger than the weak nuclear force. The weak nuclear force is in turn ten million billion billion times stronger than gravity. (To give you some sense of scale, that’s the same number we used to compute the rarity of astatine.) Gravity dominates our everyday lives only because the strong and weak nuclear forces have such short reach and the balance of protons and electrons around us is equal enough to cancel most electromagnetic forces.
“un.bi.bium”: After decades of scientists having to build super-heavy elements laboriously, atom by atom, in 2008 Israeli scientists claimed to have found element 122 by reverting to old-style chemistry. That is, after sifting through a natural sample of thorium, the chemical cousin of 122 on the periodic table, for months on end, a team led by Amnon Marinov claimed to have identified a number of atoms of the extra-heavy element. The crazy part about the enterprise wasn’t just the claim that such an old-fashioned method resulted in a new element; it was the claim that element 122 had a half-life of more than 100 million years! That was so crazy, in fact, that many scientists got suspicious. The claim was looking shakier and shakier, but as of late 2009, the Israelis hadn’t backed off from their claims.
“once-dominant Latin in science”: Regarding the decline of Latin, except on the periodic table: for whatever reason, when a West German team bagged element 108 in 1984, they decided to name it hassium, after the Latin name for part of Germany (Hesse), instead of naming it deutschlandium or some such thing.
“rectilinear shapes”: It’s not a new version of the periodic table, but it’s certainly a new way to present it. In Oxford, England, periodic table taxicabs and buses are running people around town. They’re painted tires to roof with different columns and rows of elements, mostly in pastel hues. The fleet is sponsored by the Oxford Science Park. You can see a picture at http://www.oxfordinspires.org/newsfromImageWorks.htm.
You can also view the periodic table in more than two hundred different languages, including dead languages like Coptic and Egyptian hieroglyphic, at http://www.jergym.hiedu.cz/~canovm/vyhledav/chemici2.html.
BIBLIOGRAPHY
These were far from the only books I consulted during my research, and you can find more information about my sources in the “Notes and Errata” section. These were simply the best books for a general audience, if you want to know more about the periodic table or various elements on it.
Patrick Coffey. Cathedrals of Science: The Personalities and Rivalries That Made Modern Chemistry. Oxford University Press, 2008.
John Emsley. Nature’s Building Blocks: An A–Z Guide to the Elements. Oxford University Press, 2003.
Sheilla Jones. The Quantum Ten. Oxford University Press, 2008.
T. R. Reid. The Chip: How Two Americans Invented the Microchip and Launched a Revolution. Random House, 2001.
Richard Rhodes. The Making of the Atomic Bomb. Simon & Schuster, 1995.
Oliver Sacks. Awakenings. Vintage, 1999.
Eric Scerri. The Periodic Table. Oxford University Press, 2006.
Glenn Seaborg and Eric Seaborg. Adventures in the Atomic Age: From Watts to Washington. Farrar, Straus and Giroux, 2001.
Tom Zoellner. Uranium. Viking, 2009.
THE PERIODIC TABLE OF THE ELEMENTS
ABOUT THE AUTHOR
SAM KEAN is a writer in Washington, DC. His work has appeared in the New York Times Magazine, Mental Floss, Slate, Air & Space/Smithsonian, and New Scientist. In 2009, he was the runner-up for the National Association of Science Writers’ Evert Clark/Seth Payne Award for best science writer under the age of thirty. He currently writes for Science and is a 2009–2010 Middlebury Environmental Journalism fellow.