George Mason U. professor finds direction of local interstellar magnetic field (Forwarded)

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George Mason University

Media Contact:
Tara Laskowski, 703-993-8815

05/11/2007

MASON PROFESSOR FINDS DIRECTION OF MAGNETIC FIELD

Merav Opher's model suggests that our solar system's shape is asymmetric

FAIRFAX, Va. -- Merav Opher, assistant professor of physics and astronomy at
George Mason University, and her colleagues Ed Stone of the California
Institute of Technology and Tamas Gombosi from the University of Michigan
recently published a paper in Science magazine that suggests the direction
of the local interstellar magnetic field, located just outside of our solar
system.

The paper, "The Orientation of the Local Interstellar Magnetic Field," uses
data sets gathered from the Voyager spacecrafts, which recently crossed the
termination shock at the edge of the solar system after having been launched
in 1977.

Up to now, scientists have believed that the magnetic field outside of our
solar system was parallel to the galactic plane. But Opher, Stone and
Gombosi used two data sets to conclude that the magnetic field is actually
60-90 degrees perpendicular to the plane.

Their data also strongly suggests that the solar system is asymmetric. While
scientists thought the northern and southern hemispheres would be similar,
Opher's team has found that the southern hemisphere is more compressed due
to the pull of the magnetic field.

Even the eastern and western hemispheres don't look the same, giving our
solar system more of a bullet shape.

"Scientists have often looked at the larger scale magnetic fields of the
galaxy. The work we are doing is on a much smaller scale, looking just
beyond our solar system. It is like looking at our backyard and opposed to
looking at the country," says Opher. "For the first time we know what the
local magnetic field looks like, and astronomers will be very excited about
this."

Opher is the only female scientist -- and by far one of the youngest
scientists -- working to calculate the flow of particles and magnetic fields
at the edge of the solar system.

Many millions of miles past Pluto, the solar wind of our sun begins to lose
its dominance when it comes into contact with the interstellar wind from the
rest of our galaxy. Scientists consider the place where the two winds meet
-- called the heliopause -- as the edge of our solar system. Opher analyzed
radio emissions from the heliopause and the streaming direction of ions from
the termination shock, which is the area where the million-mile-per-hour
solar wind slows to about 250,000 miles per hour.

Their work suggests that the field orientation of the local magnetic field
differs from that of a larger scale interstellar magnetic field thought to
parallel the galactic plane. This conclusion will have an enormous impact on
the way physicists and astronomers measure the physics and properties of the
areas beyond our solar system.

About George Mason University

George Mason University, located in the heart of Northern Virginia's
technology corridor near Washington, D.C., is an innovative, entrepreneurial
institution with national distinction in a range of academic fields. With
strong undergraduate and graduate degree programs in engineering,
information technology, biotechnology and health care, Mason prepares its
alumni to succeed in the workforce and meet the needs of the region and the
world. Mason professors conduct groundbreaking research in areas such as
cancer, climate change, information technology and the biosciences, and
Mason's Center for the Arts brings world-renowned artists, musicians and
actors to its stage. Its School of Law is recognized by U.S. News and World
Report as one of the top 50 law schools in the United States.