| Dawn Levy, News Service Stanford
University
 Astronaut
and solar physicist Loren Acton will deliver the 21st annual Bunyan
Lecture at 7 p.m. Wednesday, May 2, in Terman Auditorium. The
talk, which is free and open to the public, is titled "The
Magnetic Personality of the Universe." Stanford's Astronomy
Program in the Physics Department sponsors the Bunyan Lectures,
which are intended to bring the latest findings in cosmology research
to the public and explore their impact on society.
"The
study of magnetism has been a dominant factor in the destiny of
the human species," Acton said in a phone interview. "Our
lives have been changed by electronics. What happens to us as
people is often determined by our ability to control, understand
and use electronic forces."
Scientists
have made a number of discoveries recently about magnetic fields
in space, he said. Acton's own work revolves around the largest
magnetic laboratory in our collective backyard -- the sun. A professor
of physics at Montana State University in Bozeman since 1993,
Acton leads a research effort to monitor changes in the sun's
blistering-hot outer corona. Temperatures in the corona can exceed
1 million degrees, Acton said, and the heat induces atoms in the
corona to emit X-rays. Acton helped to design and build an X-ray
telescope that monitors these emissions. The telescope orbits
the Earth as part of a Japanese satellite mission called YOHKOH,
which means "sunbeam."
YOHKOH has
taken more than 4 million pictures of the sun since its launch
a decade ago. The YOHKOH team anticipates continuing the observations
until 2008, when the satellite is projected to reenter the Earth's
atmosphere. Acton said study of the solar corona over a long period
of time lets researchers link coronal changes to the solar cycle,
in which the sun's magnetic field swaps north with south every
22 years. Acton will present results from the project to the scientific
community at 4 p.m. Thursday, May 3, in a technical talk titled
"Solar Cycle Dependence of Coronal Activity as Observed by
Soft X-ray Telescope on YOHKOH." The talk will be held in
the second floor conference room of the Varian Building.
The allure
of space had a lot of influence on Acton when he was in school.
Space science opened up a host of new ways to explore the world.
"The space program was just taking off," he said. "It
was like taking off your dark glasses you could see the
universe in a way that you'd never been able to before."
His doctoral
dissertation at the University of Colorado in 1965 dealt with
very early measurements of solar X-rays. "It was so much
fun, I've been doing it ever since," he said.
Acton worked
in Palo Alto at Lockheed research labs from 1964 to 1993. He was
working there in 1977 when NASA accepted Lockheed's proposal for
a space shuttle experiment. In July 1985, Acton found himself
in orbit, operating solar telescopes during eight days on the
space shuttle Challenger. Escaping the Earth's atmosphere is critical
for making precise observations, as atmospheric interference can
clutter up data. "By putting a telescope in space, every
picture was perfect," Acton said. "And when you saw
things happen, you had to believe them and try to interpret them."
The space
experiments suggested that gas motions in the sun's outer atmosphere
are strong enough to push around the magnetic field, Acton said.
"This probably results in energy storage in the corona,"
he said, which may contribute to making the corona hotter than
the visible surface of the sun.
In addition
to his work on the X-ray experiment on YOHKOH, Acton has been
principal investigator on many NASA research programs, including
eight rocket experiments, all in the area of solar X-ray studies.
Among his
many awards, Acton has received the 2000 Hale Prize for long-term
contribution to solar physics from the American Astronautical
Society, the 1993 NASA Exceptional Scientific Achievement Medal,
the 1988 Robert E. Gross Award for technical excellence at Lockheed
Corp. and the 1986 Spaceflight Achievement Award of the American
Astronautical Society. He also holds an honorary doctorate from
Montana State University.
Contact:
Dawn Levy, News Service (650) 725-1944; e-mail: dawnlevy@stanford.edu
|
