It's been a productive year for science and technology. Researchers have sequenced key genomes, discovered an entirely new order of insect and probed the outer reaches of the solar system with surprising results, to name but a few advances. Of course, 2002 also had its low points, perhaps most notably two prominent cases of fraud in physics. But in all, the progress outweighs the setbacks. From the hundreds of stories that ScientificAmerican.com has featured over the past year, we have selected the 25 that most impressed us--some with their importance, others simply with their gee-whiz appeal. We hope you enjoy these highlights, which appear in no particular order below. --The Editors

Controlling Robots with the Mind

People with nerve or limb injuries may one day be able to command wheelchairs, prosthetics and even paralyzed arms and legs by "thinking them through" the motions.

Scientists Sequence Genomes of Malarial Parasite and Mosquito

Malaria continues to plague the world's population, particularly inhabitants of sub-Saharan Africa, where it kills at least one person every 30 seconds. Efforts to eradicate the disease in the 1950s and 1960s met with failure, and current control measures such as antimalarial drugs are swiftly losing their potency. Now researchers have sequenced the genetic codes of the most deadly malarial parasite and a mosquito that carries it.

Cosmic Microwave Background Radiation's Polarization Detected at Last

Although it was discovered less than 40 years ago, the cosmic microwave background (CMB) radiation has been around a lot longer than that. A relic from the early days of the Universe more than 14 billion years ago, the CMB is the oldest radiation on record. Current cosmological models posit that the CMB should be slightly polarized but this property has never been observed--until now.

Mouse Genome Sequenced

In the name of science, researchers have fashioned numerous kinds of mice: fat, thin, hairless, or afflicted with a particular disease, to name a few. The first draft sequence of the mouse genome should make the tiny rodents even more helpful for future research into a variety of diseases.

Astronomers Discover Icy World Far Past Pluto

Astronomers have discovered the largest object in the solar system since Pluto was identified more than 70 years ago. The object, dubbed Quaoar (pronounced "kwa-whar") by its discoverers, is approximately half Pluto's size and nearly four billion miles away from Earth.

Stamp-Size Plastic Chip Provides New Approach to Cryptography

Modern encryption techniques are tested every time someone makes a purchase over the Internet or spends electronic cash stored in smart cards. These strategies rely on so-called one-way functions, which are easy to execute in one direction (for instance, multiplying two prime numbers) but difficult to reverse (factoring a large number into two primes). With ever-increasing computer power and advances in quantum computing, however, such methods may soon become breakable. Researchers have developed a new approach to cryptography--built around a piece of plastic the size of a stamp--that is hard to crack and nearly impossible to forge.

Meet the Oldest Member of the Human Family

After more than a decade of digging, researchers working in Chad have made the fossil discovery of a lifetime: a nearly complete skull said to belong to the oldest and most primitive member of the human family yet known. Nicknamed Touma?or "hope of life" in the local Goran languageit belongs to an entirely new genus and species of hominid, Sahelanthropus tchadensis. And at almost seven million years old, it has taken scientists several crucial steps closer to the point in time at which humans and chimpanzees diverged. Yet as is the case for most spectacular finds, this one raises as many questions, if not more, than it answers.

Attacking Anthrax

The end came fast for the five people who died of inhalation anthrax last fall, all victims of the first purposeful release of anthrax spores in the U.S. Within days of showing initially unalarming symptoms, they were gone, despite intensive treatment with antibiotics. Those cases, and the near deaths of other victims, starkly highlight the need for additional therapies in the event of future attacks. Fortunately, researchers began studying the causative bacterium, B. anthracis, and seeking antidotes long before fall 2001. Recent findings are now pointing the way to new medicines and improved vaccines.

Crafty Crow Rivals Primates in Toolmaking

The ability to make tools was once thought to lie solely within the purview of humans. Then in the 1960s Jane Goodall discovered that chimpanzees, too, fashion implements to perform certain tasks. Since then, researchers have observed tool use in a variety of animals. Nonhuman primates are widely thought to be the most sophisticated tool-users after us. But observations of an innovative New Caledonian crow named Betty could alter that view.

New Findings Fan Debate over Origin of Vinland Map

Ever since it surfaced in 1957, the Vinland Map has been controversial. Some experts purport that it was drawn in the 15th century and that it chronicles the Vikings' travels to the New World, prior to Christopher Columbus's 1492 journey. Others argue that it is instead the work of a 20th-century counterfeiter. The results of two new studies are adding further fuel to the debate.

Avoiding the Impact

On June 15, 2002, an asteroid the size of a football field, dubbed 2002MN, came within 120,000 kilometers of hitting Earth. The rocky body was traveling at a speed of 36,800 kilometers per hour--and if it struck, it would have wreaked as much destruction as a nuclear weapon. It was one of the closest passes ever recorded for an object of that size. And astronomers didn't detect it till three days afterward.

Element 118 Dropped from Periodic Table

Scientists at Lawrence Berkeley National Laboratory (LBL) have formally retracted their claims for the discovery of the most massive chemical element. The synthesis of the "superheavy" element 118, comprising 118 protons and 175 neutrons, was announced in a 1999, and the results appeared to confirm theories from the 1970s that predicted heightened stability for nuclei containing around 114 protons and 184 neutrons.

First Humans to Leave Africa Weren't Necessarily a Brainy Bunch

A longstanding view of human evolution holds that the first hominids to leave Africa did so with the help of bigger brains, longer legs and fancier tools than those of their predecessors. That scenario suffered a major blow a couple of years ago, however, when paleontologists working in Dmanisi, Georgia unearthed the oldest human remains yet found outside of Africa---two 1.7-million-year-old skulls belonging to early members of our genus, Homo--and discovered primitive tools alongside them. A new finding may topple another pillar of the theory. Researchers working at the same site have recovered a third skull--one that housed a surprisingly small brain.

Study Casts Doubt on Cell from Hell's Role in Fish Kills

During the 1990s, massive fish kills plagued bays and estuaries along the East Coast of the U.S. People living near and working on these waters also complained of memory loss, headaches and other physical ailments. Scientists blamed these frightening phenomena on a microorganism named Pfiesteria piscicida, often referred to as the "cell from hell" in media coverage of the disturbing events. Studies indicated that the diminutive creature, which belongs to a group of free-living marine organisms known as dinoflagellates, had as many as 24 life-cycle stages, some extremely toxic. Now, however, researchers assert that Pfiesterias life cycle is much simpler than originally thoughtand that the organism is actually nontoxic.

Light's Information-Carrying Capacity Doubles

The computer behind the screen on which this article appears processes commands a bit at a time, using units of information comprised of either zeros or ones. Scientists can likewise use light to encode information because photons exist in one of two possible spin states. But photons also carry a property known as orbital angular momentum (OAM), which can take on an infinite number of values. A reliable method of measuring orbital angular momentum might therefore lead to a way of packing significantly more data into a beam of light.

Study Shows How Far GM Pollen Spreads

For years, debates have raged over the use of genetically modified crops in commercial agriculture. Many believe that GM crops will spread their altered genes to weeds and other unintended targets. The fear persists that many undesirable plants could become resistant to certain herbicides because they have altered genes. To that end, new findings may alleviate some concerns while fueling others.

Gladiators: A New Order of Insect

Imagine being the very first person ever to see a butterfly, a beetle or a wasp. Imagine the sense of wonder at a world so wide that it contains not just undiscovered species, genera or families but entire orders of life yet to be named. For nearly a century researchers have assumed that every newfound species of insect will fall into one of just 30 basic categories. But in June 2001 something happened that changed the way biologists look at the insect world, giving them a taste of the old joy of discovery--and renewing their awe at the variety of life.

Scientists Sequence Rice Genome

In a move that may lead to hardier versions of one of the world's most important foods, scientists have unveiled two maps of the rice genome. These draft DNA sequences of the plant could help speed improvements in the nutritional quality and yields of a crop that is a staple for more than half the world's population.

Climate Warming Causes Collapse of Antarctic Ice Shelf

The northern section of the Larsen B ice shelf--a thick slab of floating ice on the eastern side of the Antarctic Peninsula--has collapsed and separated from the continent, researchers report. The incident, which was monitored and recorded by satellite images, aerial photography and a research vessel navigating through the resulting icebergs, is the largest single event in a 30-year series of ice shelf retreats in the area.

Chinese Fossil May Be Mother of All Placental Mammals

Researchers have unearthed the fossilized remains of what may be the mother of all placental mammals, so-named for the placenta that nourishes their young during gestation. The 125-million-year-old specimen is the earliest and most primitive known representative of the placental group, to which the vast majority of living mammals--humans among them--belong.

Scientists Spin Spidery Silk

Few things appear as delicate as a spider's web, each gossamer strand one-tenth the width of a human hair. Yet pound for pound, the sturdiest spider silks are stronger than steel and stretchier than nylon. With such remarkable properties, it's no wonder that researchers have made numerous attempts to synthesize spider silk for industrial and medical applications. (Efforts to farm the arachnids have failed as a result of their territorial nature.) Indeed, in the words of one scientist, this goal has long stood as the "Holy Grail of material science."

Physicists Create a New State of Matter

Cool a gas of rubidium atoms to one-hundred-millionth of a degree above absolute zero or less and something strange happens. The atoms lose their individuality and merge into a single quantum state, forming what is known as a Bose-Einstein condensate (BEC). In this condensate atoms flow without friction, endowing the ultracold gas with the property of superfluidity. Scientists have known that much since 1995. Now new research has taken that work one step further, revealing a surprising BEC behavior. It appears that under certain conditions, the condensate undergoes a reversible quantum phase transition, switching from a superfluid to a patterned fluida new type of matter.

T. rex Not Fleet of Foot, Study Shows

It was big and it was mean, but Tyrannosaurus rex wasn't fast. In fact, the dinosaur we most love to hate may not have even been able to run at all. Contrary to previous suggestions that the beast could reach running speeds of up to 45 miles per hour, new research indicates that such swiftness would have been biomechanically unfeasible.

Scientists Succeed in Transplanting Cloned Cow Tissue

Because the human body rejects most introduced tissue, locating an organ that will be accepted by a patient's immune system remains a significant challenge for transplantation medicine. Creating cells that are genetically identical to those of the patient offers one solution to this problem. The results of a new study illustrate that, though it is not yet feasible in humans, this approach can work in cows.

Mars Odyssey's Measurements Reveal a Wet, Red Planet

Dry valleys, channels, and networks of gullies scar the arid Martian landscape. Along with other evidence, these physical vestiges of conditions on ancient Mars suggest a planet once saturated with liquid water. Where is this water now? Scientists have posited that a portion of it evaporated into the atmosphere, but that the rest lies beneath the surface. According to new data, large deposits of water ice may in fact exist under just tens of centimeters of soil on the Red Planet.