Nearly every gadget you might usefrom a hair dryer to a Gameboyexploits the electron's negative charge by design. But apart from charge, electrons possess another fundamental traitnamely, spinthat could give rise to a whole new class of electronic devices. This past year, scientists made several advances in the fieldfinding ways to create "spin polarized" electric currents in semiconductors; pass electron spin from one semiconductor to another; and spin electrons using electricity.
Stopping Light in its Tracks
In January two independent teams of scientists announced that they had found a way to reduce the speed of light to zero. Although light in a vacuum moves at a neck-breaking 186,000 miles a second, materials with a high refractive index can slow it down. The ability to bring light to an utter standstill could find ample use in quantum computers.
First Doubly-Strange Nuclei
Strangeness can be hard to studyespecially on the atomic scale. But in August a collaboration of 50 researchers from 15 different institutions announced results that could make it easier for scientists to probe strange matter in the near future. Using the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratories, the team successfully produced for the first time structures containing one proton, one neutron and two lambda particles, each comprised of an up, a down and a strange quark.
World's Most Accurate Clock
Since 1967, scientists have defined a single second according to microwave-frequency transitions in cesium, "ticks" that occur roughly once each nanosecond. Optical transitions in atoms take place more frequently and can thus meter out smaller divisions of time. But until recently, researchers had no way to tally the faster ticks. In July, however, physicists devised the first-ever all-optical atomic clock, allowing them to divide time down to the femtosecond.
First Room-Temperature Single-Electron Transistor
From a carbon nanotube, Dutch researchers have crafted a transistor that toggles on and off with the flow of a single electron. It is the first such single-electron transistor (SET) to operate at room temperature, and given its efficiency and size, the scientists suggest it represents a big step forward in the quest to create ever-smaller computer components.
World's Most Energetic Beam of Light
Physicists bested a world record this past May, coaxing the most energetic beam of light yet from a mirrorless free-electron laser. Although the laser fell short of delivering x-raysthe ultimate goal of this kind of synchrotron radiation researchthe beam produced in the experiment was 1,000 times more energetic than previous attempts, having a wavelength of 385 nanometers. The scientists hope that free-electron lasers will become the next-generation x-ray source for a range of research problemsfrom probing the structure of single proteins to studying so-called warm, dense matter.
After months of trying, on October 13, 2001, scientists at Advanced Cell Technology came into their laboratory to see under the microscope what theyd been striving forlittle balls of dividing cells not even visible to the naked eye. Insignificant as they appeared, the specks were precious because they were, according to ACT, the first human embryos produced using the technique of nuclear transplantation, otherwise known as cloning.
First Genetically Modified Primate
Researchers succeeded in producing the first genetically modified primate, according to a report published in January. The baby rhesus monkey, dubbed ANDi (backwards for inserted DNA), carries an extra gene that was slipped into his mother's egg prior to fertilization. Such engineering may ultimately point the way to improved gene therapy treatments for human diseases.
Cloning Endangered Species
Although attempts to clone endangered mammals such as the argali and the gaur failed to yield viable offspring, a European research team met with success in October. Via the same technique used to replicate Dollysomatic cell nuclear transferthey produced an apparently healthy mouflon lamb, a member of an endangered species of sheep found on Sardinia, Corsica and Cyprus.
Human Genome Analysis
The world celebrated when scientists from the Genome Project, an international consortium of academic research centers, and Celera Genomics, a private U.S. company, both announced that they had finished working drafts of the human genome in 2000. But these drafts revealed only the beginning of the story. In February both teams announced the results of their initial analyses, which revealed, among other surprises, that humans have a mere 26,000 to 40,000 genes, or far fewer than many people predicted.
Foot and Mouth Epidemic
In early February foot and mouth disease (FMD) started to spread like wildfire through the English countryside, fanning out from a single pig herd in Northumberland to more than a million animals on some 45,000 farms. As of early April, the British Ministry of Agriculture, Fisheries and Food (MAFF) reported that 1,580,000 animals had been slaughtered or marked for slaughter.
9/11: The Psychological Aftermath
Since September 11th, Americans have become more anxious than ever. Before the terrorist attacks on the World Trade Center and the Pentagon, anxiety-related disorders cost the U.S. $42 billion a year in medical and work-related losses. Now mental health professionals estimate that 100,000 people in New York alone are at risk for post-traumatic stress disorder.
First Complete Trans-Atlantic Robotic Surgery
The first complete surgery performed by doctors on one continent controlling robotic instruments on another went off without a hitch, researchers reported in September. Surgeons in New York removed a 68-year-old womans gall bladder as she lay across the ocean in Strasbourg, Francemore than 7,000 kilometers away.
Study Finds Placebo Effect Is Fake
The placebo effect may have no scientific basis, according to a study published in May. Doctors have long known that about 35 percent of all patients given a placebo will get better, and they had assumed it was because the patients believed the dummy medication would help them. Many people have taken the idea a step further, believing that we can "think ourselves well" to some extent.
Researchers Find Huntington's Fatal Flaw
Two laboratories at Johns Hopkins Medical Institutions reported in March that they had not only discovered the biological flaw behind Huntington's disease but also were able to correct it in cultured cells. The findings could eventually lead to drug treatments for the devastating neurodegenerative condition, characterized by jerky, involuntary movements and progressive dementia. And more broadly, the results may shed light on a class of disorders known as triple-repeat diseases, to which Huntington's belongs.
First Evidence of a Human Response to Pheromones
Scientists have found evidence of a response to pheromones in the human brain, a report published in August claimed. These volatile compoundssecreted by one member of a species to elicit a response (either behavioral or physiological) from another individualand their use in communication has long been documented in lower mammals such as rodents and pigs.
Limit to Neuron Growth
The finding a few years ago that adult primates, including humans, could produce new neurons garnered much excitement. Ever since, scientists have been searching for further evidence, in various parts of the brain, that this is indeed the case. According to a study published in December, though, adults primates can't create new neurons in the most sophisticated part of the brain, the neocortex.
Biologists have long recognized morphological differences between Africa's forest-dwelling elephants and those that inhabit the savanna. But they have always considered the two types to be members of the same threatened species. The results of a genetic study described in August, however, indicate that the elephants form distinct groups and thus merit recognition as separate species.
Chandra's Black Hole
A giant x-ray flare from the heart of our galaxyrecorded by the Chandra X-ray Observatory last yearbrought astronomers closer than ever to a black hole that most believe lurks there. New analyses of the brilliant burst are helping researchers to test several theories about the black hole and to put new limits on its size.
Much to the surprise and delight of mission controllers here on Earth, the Near Earth Asteroid Rendezvous (NEAR) Shoemaker spacecraft glided in for a soft landing on February 12, 2001, on the surface of 433 Eros, an asteroid 196 million miles away. As the tiny car-size craft neared its final destination, it took 69 detailed photographs of the space rock, revealing features as small as one centimeter across.
First Look at Dark Matter Object
Dark matterthe mysterious material that makes up most of the universeis notoriously difficult to see. But a new report in December suggested that scientists have directly observed a dark matter object for the first time.
Planetary System Akin to Our Own
In August, astronomers announced that they had detected a Jupiter-size planet orbiting the star 47 Ursae Majoris in the Big Dipper. The second planet to be found circling this star, this discovery revealed the first evidence yet of a planetary system akin to our own.
Missing Solar Neutrinos Found At Last
For more than three decades, physicists have been looking for, well, next to nothingelementary particles of matter called electron-neutrinos that have no charge and practically no mass. Nuclear reactions that fuel the sun should churn out vast quantities of these particles, and yet previous measurements have indicated that only about half the number predicted ever reach the earth. In June, scientists finally announced that they had found the missing neutrinos.
Hairless, legless and confined to the sea, whales make for unlikely mammals. But millions of years of evolution can yield surprising results. In the case of whales and their cetacean kin, it led to one of the most dramatic transformations known, producing fully aquatic mammals from terrestrial ones. New fossils have settled one heated debate over whale origins but fan the flames of another.
Colossal Cretaceous Crocodile
Paleontologists working in Niger's Tnr Desert unearthed the fossilized remains of a crocodile that might give even Steve Irwin pause. According to a report published in October, this bigger, badder cousin of modern crocs measured up to 40 feet long and weighed in at eight metric tons. Dubbed Sarcosuchus imperator, the Cretaceous beast may have preyed on dinosaurs.
Fetal Titanosaurs in Fossilized Eggs
Adding to the wealth of information gleaned from the discovery a few years ago of a Late Cretaceous dinosaur nesting ground in Patagonia, researchers unearthed from the site six fossil eggs complete with fetal titanosaurs. The newly found embryos, described in a report published in September, feature beautifully preserved skulls that provide insight into the evolutionary development of these beasts.
Oldest Human Ancestor Yet
Researchers working in Ethiopia uncovered the remains of a creature thought to occupy a spot on the family tree quite close the evolutionary branching point between humans and chimpanzees. According to a report published in July, these remains belong to a new subspecies of the hominid genus Ardipithecus, previously known fossils of which date to 4.4 million years ago. The new fossils, however, come from sediments dated to between 5.2 and 5.8 million years ago, and thus may represent the earliest known human ancestor.
Enormous Egyptian Dinosaur
Paleontologists working in Egypt's Bahariya Oasis, some 180 miles southwest of Cairo, happened upon the remains of one of the largest dinosaurs yet discovered, according to findings reported in June. The team estimates that the new beast, which they have named Paralititan stromeri, measured around 90 to 100 feet long and weighed up to 80 tonsmaking it a close second to the current record holder, Argentinosaurus.
Feathers Came Before Flight
An exquisitely complete feathered dinosaur emerged from the famed fossil beds of northeastern China's Liaoning Province this past year. The discovery, announced in April, gives further weight to the argument that birds evolved from dinosaurs and provides the strongest evidence yet that feathers predate the origin of flight.
Glass-Eating Microbes Alter Earth's Oceanic Crust
It may sound like a masochistic activity, but for certain microbes, eating volcanic glass is an entirely natural thing to do. In fact, according to a report published in September, such snacking abounds below the seafloor. This, researchers say, suggests that a significant proportion of the oceanic crust alterations long attributed to a chemical-physical process may stem from a biological one.
More Evidence of Global Warming
It's not your imagination. Spring is arriving earlier and fall, somewhat laterat least if you live above 40 degrees north latitude, the line that intersects New York, Madrid and Beijing. An analysis of two decades of satellite data, published in September, confirmed that the growing season in the Northern Hemisphere is getting longer and plant life is becoming more lush as wellvery likely as a result of global warming. In July two scientists made a prediction that the earth may warm four to seven degrees by 2100. And other reports this year blamed global warming for disrupting the breeding patterns of frogs and birds.
Geologists Debunk Myths
The Oracle of Delphi spoke through the Pythia, an elderly priestess who would fall into a trance state and utter cryptic predictions about war, agriculture and other vital matters of the time. According to ancient authorities, gaseous emissions induced the Pythia's trance state. But after French archaeologists failed to find the famed vapors a century ago, that explanation was dismissed. A study published in August revealed that the purported trance-inducing gases may have been very real after all. And in a report in June, another geologist, who has also studied the emissions at Delphi, suggested that sightings of the Loch Ness monster may result from water ripples created along a seismic fault under the lake.
First Public Images of Hydrothermal Vents in Indian Ocean
In April an international team of scientists released the first images to the public of a collection of hydrothermal vents in the Indian Ocean. To find these vents, located two and a half miles below the sea surface in one of the most far-removed places in the world, the team used the Remotely Operated Vehicle (ROV) Jason and the Woods Hole Oceanographic Institution's Research Vessel Knorr.
The Oldest Rock on Earth
A rock found in the Australian desert nearly 20 years ago yielded the oldest-known zircon crystal on the earth. In January scientists reported that the composition of this ancient crystal offers new ideas about the state of our planet 4.4 billion years ago.
World Trade Center
When New York City's giant World Trade Center towers plunged to earth following successive suicide terrorist attacks on September 11th, the world was confronted with one of most shockingand sickeningsights of modern times. One month after the attack, a panel of Boston area-based civil and structural engineers convened to discuss the fate of the superskyscrapers, struck by hijacked passenger planes. Their starkly sobering analyses highlighted the vulnerabilities of ultratall buildings to fire and pointed out steps that could be taken to lessen them.
First Single-Molecule Circuit
In a remarkable feat of engineering, researchers at IBM wired up a working computer circuit within a single carbon nanotube. Building on earlier work, Phaedon Avouris and colleagues turned the nanotubeessentially a sheet of carbon atoms rolled into a supertiny strawinto a voltage inverter, or NOT gate, one of the three fundamental types of logic gates on which all computers rely.
Scientists at Sandia National Laboratories unveiled in July the sharpest screen yet. The 10-feet-tall, 13-feet-wide device boasts a 20-million-pixel digital display that approaches the visual acuity of the human eye. Sixty-four computers work in unisonin a setup analogous to parallel computingto project complex data sets onto the display, comprised of 16 screens arranged in a four-by-four matrix. The Sandia cluster, as it is called, can exhibit large data sets in seconds, and the researchers expect that the resulting images will provide a better view of the dynamics in complicated systems, such as fires.
New, Warm Fuel Cell
In the furious race to perfect fuel cells for use in electric cars and other commercial products, researchers from the California Institute of Technology may have taken the lead, describing in April an intriguing new design. They created a novel fuel cell by combining features from existing "hot" and "cold" cells. As their names imply, these devices operate only at temperatures above 600 degrees Celsius or below 100 degrees Celsius, respectively.
As Scientific American editor George Musser discovered this past fall, it is frighteningly easy to buy chemical weapons material through the mail. Only two months after the attack on the World Trade Center, Musser had delivered to the magazine's midtown Manhattan offices all the ingredients necessary to make sarin nerve gas. Some experts believe it is just too hard to make and disperse deadly gases; others think we shouldnt underestimate terrorists ability and recklessness. But everyone agrees that we shouldnt make it easy for them, which is why our experience was so sobering.
Microscopic Metallic Bar Codes
In a move sure to confound grocery and convenience store checkers the world over, intrepid chemists fashioned microscopic bar code rods just a few thousandths of a millimeter long. These striped metal cylinders should make it easier for researchers to scan small samples for the presence of many different biological molecules at once.
Dry Water Droplets
When does spilling water not make something wet? This question may sound like the beginning of a riddle, but scientists at the College of France in Paris reported in June that they had actually found a way to move a liquid across a surface while keeping it dry. They hope the liquid marbles will find uses in technological applications that need small amounts of liquid moved quickly across a solid surface.
New Material Reverses Snell's Law
Until this past year, all known materials had a positive index of refraction. But scientists from the University of California at San Diego described in April a strange composite that has a negative index, essentially reversing Snell's law. This new mix of fiberglass and copper rings and wires is far more than a curiosity. It may very well lead to novel electromagnetic devices and even perfect lenses, unhindered by diffraction limits and thus capable of focusing light in unforeseen ways.
In April, scientists accidentally produced a new kind of rubbery plastic similar to the rubbers used in adhesives and shoe soles. The novel material, formed from two common petroleum products, promises production costs considerably lower than those of comparable polymers. And in February, chemists devised a remarkable self-healing synthetic material that, when put under stress, can fill its own cracksan ability that could extend the shelf life of a range of products that rely on plastic parts, including microelectronics.
On July 19, 2001, the Code Red worm infected hundreds of thousands of computers in less than 14 hours, overloading the Net's capacity. Chillingly, the attack may forewarn of similar but much more virulent Internet infections to come, researchers say. Future covert assaults on your own PC could force it to become an unknown hackers unwitting pawnin the lingo, a "zombie"in the next round of computerized carnage.
Do you know what your computer is doing when you're not looking? Maybe you've signed up to participate in SETI@home, a program that harnesses the distributed computing power of volunteer PCs to look for radio signals from space. If so, you've downloaded special software. But a new kind of Internet-based distributed computing described in August can use your machine without your knowledge or consent. Parasitic computing, as its creators call it, relies on the normal communication going on between Web servers to solve many pieces of a complex problem at the same time.
Any number of markets are somewhat biased in that one side has more information than the other. For instance, borrowers know more about their chances of repayment than lenders; company boards know more about their firm's potential profits than shareholders; and clients know more about their actual risks than insurance companies. Such markets are characterized by asymmetric information, and this year's winners of the Nobel Prize in EconomicsGeorge A. Akerlof, A. Michael Spence and Joseph E. Stiglitzare credited with laying the foundation for a general theory of how these markets behave.
Some molecules occur in two forms, called enantiomers, that differ only in the spatial arrangement of their atoms such that they are mirror images of one another. Like our hands, no matter how you twist and turn them, these molecules can't overlap and don't have the same three-dimensional structure. This property, known as chirality, has important ramifications because many biological receptors accept only one form of these molecules. What's more, the wrong form may actually do more harm than good. This year's recipients of the Nobel Prize in ChemistryWilliam S. Knowles, Ryoji Noyori and K. Barry Sharplessare honored for their work developing chiral molecules as catalysts.
Seventy years after Albert Einstein built upon the work of Indian physicist S. N. Bose and predicted that gaseous atoms cooled to extreme temperatures would abruptly gather in the lowest possible energy state, physicists finally observed the phenomenon. The discovery and subsequent investigation of this new state of mattertermed the Bose-Einstein condensate (BEC)earned Eric A. Cornell, Wolfgang Ketterle and Carl E. Wieman this year's Nobel Prize in Physics.
Medicine or Physiology
The orderly and accurate division of cells is vital to the survival of all living things. This year's Nobel Prize in Medicine or Physiology went to three biologistsLeland H. Hartwell, Paul Nurse and R. Timothy Huntwho discovered the key steps that lead up to division in eukaryotic cells. Understanding these steps, known as the cell cycle, may point to new possibilities for treating cancer. Indeed, defective control of the cell cycle contributes to chromosomal changes seen in cancer cells. And some of the genes that regulate the cell cycle can also function as oncogenes.