Random Walk

G ENESIS B OUNCES B ACK

JPL’s Genesis mission to and whose chemical com- bring back atoms from the position mirrors that of the solar wind deviated from the material from which the solar script when it delivered its system formed. cargo to the empty expanse But this cliffhanger has a of the Utah Test and Training happy ending. The top scien- Range on September 8. As tific priority, the concentrator written, one of a pair of heli- that collected oxygen atoms to copters piloted by Hollywood measure their isotopic ratio, stuntmen was to snatch the was in pretty good shape. The parachuting capsule out of second priority, a sheet of gold the sky to avoid jarring the foil to collect nitrogen atoms delicate contents. But the for the same purpose, was chute missed its cue and the undamaged. And although payload “geobraked” into the most of the wafers of sap- desert floor at a speed of 311 phire, diamond, and other kilometers per hour. brittle materials that made U. S. Air Force 388 Range Squad Range 388 Force Air S. U. Things didn’t look good up the five rotating collector when the recovery team arrays were in smithereens, the Above: The pocket-watch-shaped arrived minutes later. The wafers from each array were of capsule hit the desert floor edge- shell had split open, and the a different thickness, so each inner canister was cracked. piece can be traced back to its on and buried itself to about half Switching to Script B, the original array—essential for its diameter. crew secured the charge that determining which sample Left: The culprit is believed to should have released the had been collected when. The be a gravity switch like this one, parachutes. Only then could fragments were meticulously the capsule be dug out and photographed, numbered, which was supposed to sense the trucked to a clean room at and packaged—in more than capsule’s deceleration when it hit the nearby Dugway Prov- 3,000 small containers—and the top of the atmosphere and ing Grounds. The bulk of shipped to the Johnson Space the wreckage was sent on to Center for decontamina- initiate a sequence of events that Genesis’s builder, Lockheed tion, archival preservation, would have deployed a drogue Martin, for analysis, while the and eventual distribution to chute followed by a winglike para- science team tried to salvage various labs. Since the latter foil such as skydivers use. something—anything!—from would have involved sawing the 26 months’ worth of up the wafers anyway, one NASA/Lockheed Martin The switch was apparently material that had been col- could say we’re actually ahead installed backward. lected atom by laborious ion of the game. —DS

2 ENGINEERING & SCIENCE NO . 3 2 0 0 4 Left: Caltech professor of nuclear geochemistry Donald Burnett, Genesis’s principal investigator and lead scientist, picks through desert dirt for bits of the arrays, each of which was designed for a different particle stream. Below: The shards were sorted, and samples from all 14 types of wafer were recovered. A few of the silicon-on-sapphire and gold-on-sapphire wafers actually survived intact. Bottom: Three of the solar wind concentrator’s four segments were unscathed. About 85 percent of the fourth segment was salvageable.

Above: In the Friends series finale last May, dimwit actor Joey Tribbiani (Matt LeBlanc, at right) moved to Hollywood. He now shares an apartment with nephew Michael (Paulo Costanzo, center), a grad student at guess where? Clever, sympathetic writing gives this odd couple plenty to do, and Joey’s brassy sister Gina (Drea de Matteo, late of The Sopranos) and neighbor Alex Garrett (Andrea Anders, at left) earn a lot of laughs as well. Joey airs Thursdays at 8:00 p.m. on NBC.

A TKINS , S CHMATKINS

A health-conscious public up to long-chain molecules may be shunning carbs, but containing a thousand or Caltech chemists are em- more sugar units. (The latter bracing them. Professor of include chitin, the stuff of Chemistry David MacMillan insect exoskeletons; glycogen, and his graduate student Alan a source of ready energy for Northrup have discovered muscles and other tissues; a simple way to make their starch; and cellulose.) basic unit—the six-carbon “For the last 100 years, sugar—in two steps. This is scientists have needed many a major improvement over chemical reactions to differ- current methods, which can entiate five of the six oxygen require a dozen or more reac- atoms” in the basic sugar unit, tions. Natural carbohydrates explains MacMillan. “We range from these simple sugars simplified this to two steps

= =

Above: Six-carbon sugars have five carbon atoms that can be either “right- handed” or “left-handed.” This “handedness” determines which groups of atoms end up above and which end up below the ring plane; the rings have also been drawn unclosed. Glucose is at left, mannose at right.

2 0 0 4 ENGINEERING & SCIENCE NO . 3 3 by the invention of two new chemical reactions that are P OSTCARDS FROM T ITAN based on an old but power- ful chemical transformation known as the aldol reaction.” There are eight naturally oc- curring sugar structures in car- JPL’s Cassini spacecraft had its first close encounter with one of bohydrates, and the method Saturn’s moons on October 26, when it buzzed by Titan at an al- works for four of them. titude of 1,200 kilometers. Larger than Mercury, Titan fascinates The method also allows easy scientists because its dense, opaque atmosphere of nitrogen and access to sugars not found in hydrocarbons—thicker than a Stage 3 smog alert—is believed to nature, which is invaluable for resemble the one from which life’s precursor compounds formed medicinal chemistry, biology, on Earth. (But with a surface temperature of −180 °C, we don’t and a number of diagnostic expect Titan to be inhabited.) Here are a few of the first pictures techniques. For example, a released from the flyby. rare form of carbon known as carbon-13 is widely used as a tracer. Starting with 13C- labeled ethylene glycol, which is cheap and readily available, MacMillan and Northrup made a sugar molecule that contained 13C exclusively in only four chemical steps—a feat that previously took 44. “Carbohydrates are essential to human biology, playing key roles in everything from our growth and development to our immune system and brain functions,” says John Schwab, a chemist at the National Above: These near-infrared images show the surface at a wavelength Institute of General Medical Sciences, which supported the sensitive to methane. The large, bright feature in the center right of the research. “They also play criti- right-hand image is a “continent” named Xanadu, although whether the cal roles in plants, bacteria, dark stuff adjoining it is really a slushy methane ocean remains to be seen. and viruses. But because they The dark, narrow streaks in Xanadu may be rivers or glaciers of gasoline. are so difficult to work with, carbohydrates are not nearly The fact that they and the broad dark features run west to east (upper as well understood as DNA left to lower right) means that they are probably wind-driven. On its next and proteins. MacMillan’s visit to Titan, Cassini will release the European Space Agency’s Huygens Above: This near-ultraviolet photo technique will allow scientists of the global haze that hangs to more easily synthesize and probe, which on January 14, 2005, will parachute into the black square, a study carbohydrates, paving region shown enlarged in the left-hand image. Huygens will explore Titan’s hundreds of kilometers above Titan the way for a deeper under- atmosphere all the way down, and if the probe doesn’t drown—it has legs has been processed to approximate standing of these molecules, but is also designed to float—it may transmit data and pictures from the natural color. which in turn may lead to new classes of drugs and diag- surface for up to 30 minutes before it freezes to death. nostic tools.” Right: Cassini’s radar scanned a The paper was published region some 150 by 250 kilome- online August 12 by the Sci- ence Express website, and will ters at a resolution of about 300 appear in the journal Science meters. Few, if any, craters can be at a later date. —RT seen, showing that the surface is geologically young. But aside from the fact that it’s clearly a very complex place, and that the darker areas are probably smoother than the bright ones, not much else has been deduced yet.

4 ENGINEERING & SCIENCE NO . 3 2 0 0 4 T HE S W A T T EAM

I T ’ S I S T ! If you think it doesn’t do of sensory neurons in the much good to swipe at the fly flies, and that these neurons that’s going after the potato seem to be dedicated to the salad, guess again. You may sole task of responding to it. Information is everywhere. them—which were originally be discouraging the fly’s col- By inhibiting these neurons’ It’s not just facts and words, designed for the Industrial leagues from taking up the synapses, the researchers were but things like the instruc- Age. “We need a new intel- raid. Caltech’s David Ander- able to block the ability of tions in our genome that lectual framework to harness son, the Sperry Professor of flies to avoid CO2. “This tell our cells when to divide these advances,” says Bruck. Biology and an Investigator at shows that there is probably and when to die, and the “Some say biology is the sci- the Howard Hughes Medical a genetically determined, or daily flow of data into the ence of the 21st century, but Institute; Seymour Benzer, ‘hard-wired’ circuit mediating stock market that somehow information science will unify the Boswell Professor of CO2 avoidance behavior in motivates people to buy and all the sciences,” says Caltech Neuroscience, emeritus, and the fly,” Anderson says. sell. In an unprecedented president and Nobel Prize- a Crafoord Laureate; along Mosquitoes, on the other effort, Caltech has launched winning biologist David Balti- with Columbia University’s hand—or perhaps arm—are a university-wide initiative more. “It will be like physics

Richard Axel (who shared this attracted to the CO2 exhaled called Information Science in the 20th century, where year’s Nobel Prize in Physiol- by their warm-blooded hosts. and Technology (IST) to draw Einstein went beyond the ogy or Medicine for work on “Given the evolutionary con- back the curtain on the nature teachings of Newton—which the olfactory system) have servation of olfactory mecha- of information itself and how were enough to put people on found that the act of shaking nisms in insects, if we learn we use it. the moon—and allowed us to or shocking flies causes them about the molecular details While other universities reach into the atom and out to emit carbon dioxide as one involved in CO2 sensing in offer computer science and into the cosmos. Information component of a previously fruit flies, it could potentially software development, IST science, the understanding of unknown chemical signal that lead to repellents that act by will build information-based what constitutes information, makes other flies avoid the interfering with the recep- research and instructional how it is transmitted, en- space in which the stressful tion of CO2,” Anderson says. programs across the academic coded, and retrieved, is in the event occurred. The research Such a repellent could benefit spectrum. “To maintain pre- throes of a revolution whose involved the fruit fly, Dro- third-world countries where eminence in science, the U.S. societal repercussions will be sophila melanogaster, which mosquitoes carry malaria—or needs new and unified ways of enormous. The new Albert has been used for decades in even in the United States, looking at, approaching, and Einstein has yet to emerge, genetics experiments. How- where the mosquito-borne exploiting information in and but the time is ripe.” ever, the mechanism could be West Nile virus has become across the physical, biologi- Caltech has committed more widespread. a concern. cal, and social sciences, and to raising $100 million for The team, led by Caltech The paper appeared in the engineering,” says Jehoshua IST as part of the Institute’s postdoc Greg Suh, found that October 14 issue of Nature. (Shuki) Bruck, the Moore five-year, $1.4 billion capi-

CO2 activates a single class —RT Professor of Computation and tal campaign. Nearly $50 Neural Systems and Electrical million has already been Engineering and founding raised, in the form of separate director of IST. grants of $25 million from In the same way that the the Annenberg Foundation printing press heralded the and $22.2 million from the start of the Renaissance, and Gordon and Betty Moore the study of physics helped to Foundation. The Walter and foster the Industrial Revolu- Leonore Annenberg Center tion, technological advances for Information Science and in computation and commu- Technology, expected to be nication in the 20th century completed in 2007, will join have set the stage for the Age Watson and Moore labs as the of Information. Scientific physical home of IST. The and technological changes Moore gift will provide seed are outpacing our institu- money to establish four new tions— schools, media, indus- interdisciplinary research cen- try, and government among ters, joining the Lee Center

2 0 0 4 ENGINEERING & SCIENCE NO . 3 5 ���������� ������ for Advanced Networking and the Center for Neuromorphic Systems Engineering as IST’s ������������ conceptual anchors. The Center for Biological Circuit �������� Design will address how liv- ������ ing things store, process, and share information; the Social and Information Sciences Laboratory will investigate how social systems such as markets efficiently process im- mense amounts of noisy infor- mation, and how a better un- �������������� derstanding of them can help ���� improve society; the Center ��������� �������� ������� for the Physics of Informa- �������� tion will examine the physical ���� qualities of information and design computers and materi- als for the next generation of information technology; and the Center for the Math- ematics of Information will formulate a common language of information that research- ers from different fields can

use. —JP MSSS NASA/JPL/

JPL’s Mars rovers keep on truckin’ despite wonky wheels and other signs of middle age. At top is Spirit’s trek as of its 238th mar- tian day, or sol (September 3), superimposed on images from JPL’s Mars Global Surveyor. Spirit con- tinues to climb into the Columbia Hills, and now has more than two miles on its odometer. Meanwhile, the folks who run the Mars Orbiter Camera have figured out a way to sharpen its gaze so that the rover and its tracks can actually be seen from orbit (above left), as in this shot from March 30. And Oppor- tunity’s exploration of Endurance Crater from sol 94 through sol NASA/JPL/Cornell/OSU/MSSS 205 (August 21) is shown at left. In honor of the rovers’ unprec- edented successes, on September 28 asteroids 37452 and 39382 were officially renamed Spirit and Opportunity, respectively.

6 ENGINEERING & SCIENCE NO . 3 2 0 0 4 ���������� ������

������������ S CIENCE B Y THE S EAT OF THE P ANTS �������� ������

Sliding down a sand dune tor with Caltech’s Summer into the dune, eventually on your derrière might at first Undergraduate Research forming a band of moisture take seem a bit undignified for Fellowships (SURF) program. some two meters down. In a Caltech professor. But for Several times each summer, time this sand hardens, says Professor of Mechanical Engi- Hunt, Professor of Mechani- Hunt, forming a cement- neering Melany Hunt, it’s all cal Engineering Chris Bren- like crust. When the dune’s �������������� in the name of science. Hunt nen, and their students make surface is disturbed, friction ���� wants to know why many the long drive to the Eureka between sand grains creates ��������� desert sand dunes give off or the Dumont Dunes in the reverberations between the �������� ������� �������� sound—and a loud, droning Death Valley area, or to the dry sand on the surface and ���� sound to boot—whenever the Kelso Dunes in the Mojave the wet sand below. dune avalanches, or a strong Desert. Once there, they slog “That may be why smaller

NASA/JPL/New Mexico Museum of Natural History Natural of Museum Mexico NASA/JPL/New wind blows, or a scientist up to the dune’s crest line, dunes don’t make sound,” says slides down its side. While carting a ground-penetrating Hunt, “because they haven’t the phenomenon has been radar unit, geophones (a type been around long enough to known for centuries, what of microphone), and lots of form that hard layer of sand.” causes it remains a mystery. drinking water. The radar was The minimum needed is Below: Brennen holds a sand Most believe the answer is used to confirm the subsur- about two meters of thickness, sampler as grad student Angel Ruiz friction as grains of sand rub face existence of a band of she says. The loudest dunes Angulo pounds it into the Dumont together. But the sound con- wet, hard sand; the geophone are the tallest and the steep- tinues even after the move- recorded the noise as students est, those with a maximum Dunes and Hunt hunches over her ment has stopped, and differs and faculty alike slid down the 30-degree angle of repose; that notebook. The operation is being from winter to summer. dune. is, the steepest the dune’s face taped for the debut of a new PBS Hunt, who studies the flow Hunt believes the sound is can be without collapsing. It’s series called NOVA Science Now. of particulates and granular a resonance effect, much like a also the reason she believes the materials, has spent the last string being plucked on a mu- sound varies by the season, The show is set to air on January few summers investigating sical instrument. Over time, which affects the moisture 25, 2005. Check your local listings. booming dunes as a men- whatever rain falls percolates content. —MW

2 0 0 4 ENGINEERING & SCIENCE NO . 3 7