DECEMBER 23, 1996 VOL. 148 NO. 28

THE BEST OF 1996/SCIENCE

THE BEST SCIENCE OF 1996

BY CONTRIBUTORS GINIA BELLAFANTE, RICHARD CORLISS, CHRISTOPHER JOHN FARLEY, PAUL GRAY, BELINDA LUSCOMBE, JOSHUA QUITTNER, RICHARD SCHICKEL, MICHAEL WALSH, STEVE WULF, RICHARD ZOGLIN

1 BOOM YEAR FOR MARS In August the human race got what may be its first look at Martians--in the form of microfossils inside a meteorite. The discovery raised questions not only about extraterrestrial life but also about how earthly life began. (If life started on Mars and spread here, we could all be Martians.) In the fall Earth sent its own emissaries to Mars, launching two U.S. probes and a Russian one to the planet. The Russian craft faltered in Earth's orbit and wound up in the drink; the U.S. ships should arrive next year.

2 A ray of hope A new class of drugs known as protease inhibitors--taken with a number of other drugs in a "cocktail"--may be turning hiv infection into a manageable condition. In tens of thousands of aids patients the amount of virus in the blood has dropped below doctors' ability to measure it. The drugs are not perfect: they can cost $20,000 a year in the U.S., and the virus may yet find a way around them. But they offer the first real hope since the epidemic began.

3 Waterworlds? It always seemed likely that stars similar to the sun should be orbited by planets, but the few such planets that had been found in recent years were either too hot or too cold to sustain life. This year, however, astronomers identified a couple planets orbiting stars about 35 light-years away that appear to be the right temperature to allow water to exist in liquid form. In our world water means life; in others it could as well.

3 Attacking fat The U.S. Food and Drug Administration was busy this year, approving Redux, the first new weight-loss drug in 23 years, and olestra, an artificial fat that passes right through the body. The downsides: olestra moves too quickly through some people, leading to intestinal distress. Redux may cause its own side effects, including brain damage--in lab animals at least.

4 I can't believe it's Finnish Is self-interest the mother of invention? Food scientists in Finland--a country legendary for its love of fat--developed a margarine that may lower cholesterol up to 15%. In the U.S. the news was good too: anticholesterol drugs known as statins were shown to be so effective that doctors wonder whether even people at relatively low risk of coronary disease should be taking them.

5 A great-great-grandbird Paleontologists disagree over whether modern birds are direct descendants of dinosaurs. Proponents say yes, pointing to skeletal similarities; others argue that those parallels are just coincidence. This year the bird-as-dino camp got a boost when a dig in the Gobi Desert revealed a fossilized dinosaur doing a very birdlike thing: brooding fossilized eggs. The find may not end the debate, but it comes close.

6 A piece of the puzzle Between 2 million and 3 million years ago, descendants of Lucy, a prehuman whose bones were found in Ethiopia, evolved into true humans. But exactly when? Scientists may have found out. Scouring Lucy's home range, they discovered a 2.33-million-year-old jaw that clearly came from the genus Homo. The jaw may be the oldest Homo fossil ever found, and fills one empty limb on the family tree.

7 Bridging a gap The goal of repairing spinal injury moved closer when injured lab animals did something they weren't supposed to do again: stand up. Swedish researchers succeeded in restoring some strength and mobility in rats with severed spinal cords by building nerve bridges across the gap.

8 Marathon woman The U.S. National Aeronuatics and Space Administration's old-boy network got a jolt when Shannon Lucid earned the title of America's most experienced astronaut, returning to Earth after six months aboard Russia's space station. Lucid's record was helped along because bad weather and technical problems delayed her return almost seven weeks.

9 Maiden on ice When the Ampato volcano in Peru erupted, it melted a nearby glacier and revealed something remarkable: an exquisitely preserved Inca girl who had been sacrificed to the volcano 500 years earlier. The costume and physical condition of the maiden are telling scientists a lot about how her people lived. If her tissue yields the expected DNA, she will teach them even more.

...AND THE WORST

The spreading AIDS epidemic New drugs may be containing AIDS in the Western world, but the contagion continues to rage in the Third World and is now spreading to Eastern Europe, the former Soviet Union, southwest Asia and China. More than 3 million people were newly infected with HIV in 1996, bringing the total number of cases to 22.6 million around the world.