FAST Explorer studies Northern Lights

A UC Berkeley satellite-the second in NASA's highly touted Small-Class Explorer series of fast, cheap satellites-was launched in August to probe the mysteries of the Northern Lights.

The Fast Auroral SnapshoT (FAST) Explorer satellite skims as low as 220 miles above the aurora borealis, or Northern Lights, collecting detailed "snapshots" of the magnetic and electric fields above both the North and South Poles.

These fields accelerate electrons in the earth's ionosphere to such high velocities that they smash into atmospheric atoms and generate the beautiful shimmering curtains of light that dominate the polar night sky.

Data from the satellite will be correlated with ground observations of the aurora in an effort to explain the colorful and shifting sheets of light.

"The goal is to study the microphysics of the aurora," says project leader Charles Carlson, a research physicist at UC Berkeley's Space Sciences Laboratory. "One of the puzzles is how something global like the solar wind ends up creating a thin curtain of light around the North Pole."

FAST is part of an international, multi-satellite program to study the solar wind and its interaction with the earth's magnetosphere and ionsosphere. (The earth's magnetosphere, or magnetic field, is a teardrop-shaped magnetic "bubble" that shelters the earth from the solar wind). It joins several other satellites already orbiting the earth, most of which include instruments designed by groups at the Space Sciences Laboratory.

T. rex bit REALLY hard

The gnawed remains of a 70 million-year-old victim of Tyrannosaurus rex have provided the key to how powerful the dinosaur's bite really was.

Gregory Erickson, a graduate student in biology, teamed up with engineers at Stanford to estimate the force that created the punctures and tears in the fossilized pelvis of a hapless Triceratops discovered in Montana a few years ago. The fossil had 58 bite marks that could only have been made by a T-rex.

They found that the ferocious beast could exert between 1,440 and 3,011 pounds of force, greater than the crushing force of any known creature, though close to the maximum force exerted by the American alligator, a dinosaur relative.

"This is like the weight of a pickup truck behind each tooth," Erickson says.

The new evidence refutes an argument made by some scientists that T. rex was primarily a scavenger because its teeth were too weak to attack live prey.
Secrets of the earth revealed

With a simple but controversial assumption and lots of supercomputer time, two Berkeley geophysicists have solved a long-standing problem in geology: why the jigsaw puzzle of crustal plates on the earth's surface looks the way it does.

The problem, which has bedeviled the theory of plate tectonics since it was proposed nearly a half century ago, is that basic theories of fluid heating and convection say the surface should be broken into many small puzzle pieces, none larger than about 3,000 kilometers across.

Instead we see a smaller number of huge plates. One of these, the Pacific plate, spans nearly 13,000 kilometers at its widest.

Mark Richards, professor of geophysics, and graduate student Hans-Peter Bunge have found that a simple but fundamental assumption-that the viscosity or stiffness of the hot rock in the earth's interior increases by a factor of 30 from top to bottom-predicts exactly what is observed on the surface.

This includes not only the size of the plates but also the geometry of plate boundaries.

"This is a fundamental discovery of fluid dynamics which brings us very close to solving a major problem of geodynamics," says Richards.

The landmark feat was achieved by monopolizing a massively parallel computer (a Cray T3D) at Los Alamos National Laboratory for nearly three weeks to perform calculations on a 3-D model of the earth's mantle.

The mantle, composed of rock at high temperature and pressure, underlies the surface crust and extends 2,700 kilometers down to the earth's core.

Cal epidemiologist wins Olympic medal for research

The first two Olympic medals of the 1996 summer games went not to competitors in one of the 271 athletic events, but to an amateur runner and an avid swimmer who devoted their careers to showing the lifetime health benefits of vigorous exercise.

Ralph Paffenbarger, Jr., a research epidemiologist and physician at UC Berkeley, was awarded an Olympic medal July 14 along with British scientist/physician Jeremy Morris for independent research showing the link between physical activity and lowered risk of coronary heart disease. The medals accompanied the first $250,000 Olympic Prize in sport science.

Paffenbarger, 74, is known for his pioneering studies of Harvard graduates and San Francisco longshoremen. His findings are the subject of the new book "LifeFit," co-authored with Eric Olsen.

"We've shown without question that people of all ages, when they take up a more active lifestyle involving moderately vigorous exercise, will reduce their risk of heart disease and many other diseases," says Paffenbarger, who, since age 45, has run in 151 marathons and long distance races.

More medals

Stephen Smale, professor emeritus of mathematics, and Richard Karp, University Professor emeritus in computer science, received the National Medal of Science-the top science honor in the U.S.-this summer along with six others at a White House ceremony.

Robert Curl shared the 1996 Nobel Prize in Chemistry with two others. A 1957 PhD graduate of the College of Chemistry, he's a professor at Rice University.

Roamin' Gnomon

Some described it as an overgrown potato. Others said it's more like a beast caught in a cage. But everyone agreed the huge multimedia sculpture Berkeley mechanical engineering students helped develop, on display at the San Francisco Museum of Modern Art through Dec. 1, made a strong statement about the constraints of technology.

Called "Gnomon," the exhibit was named after an ancient Greek device for understanding space and time. It involves an egg-shaped object about the size of a minivan rolling around a gallery a bit too snug for comfort.

The artists who conceived Gnomon asked Berkeley students to help make the technology work. Using mechatronics-the science behind much of today's industrial manufacturing and robotics-class projects under the direction of professor David Auslander contributed to designing navigation and obstacle detection systems.

Gnomon was designed so it can't bump into people in the gallery or touch the walls around it. At the same time, it tries to follow a scrambled signal from satellites in the U.S. Global Positioning System.

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