Images show sun's dynamic, turbulent nature


Mar 21, 2007

The sun's magnetic field rises vertically from a sunspot.

WASHINGTON (Reuters) -- X-ray images taken from a new international spacecraft show that the sun's magnetic field is much more turbulent than scientists knew, NASA reported Wednesday.

They saw twisting plumes of gas rising from the sun's corona and reacting with the star's magnetic field, a process that releases energy and may power solar storms and coronal mass ejections, which in turn affect the Earth. A turbulent magnetic field would, in theory, generate more energy than a steady-state field.

"Theorists suggested that twisted, tangled magnetic fields might exist," Leon Golub, senior astrophysicist at the Harvard-Smithsonian Center for Astrophysics, said in a statement.

"With the X-Ray Telescope, we can see them clearly for the first time."

The spacecraft, named Hinode from the Japanese word for sunrise, was launched in September with an array of carefully designed instruments, each looking at a different layer of the sun.

It is a joint project of the U.S., European and Japanese space agencies and Britain's Particle Physics Astronomy Research Council.

"For the first time, we are now able to make out tiny granules of hot gas that rise and fall in the sun's magnetized atmosphere," said Dick Fisher, director of NASA's Heliophysics Division.

"These images will open a new era of study on some of the sun's processes that affect Earth, astronauts, orbiting satellites and the solar system."

The scientists said they were surprised and delighted by the findings.

"It's going to put us in a whole new realm of understanding," Golub told a news conference.

"Everything we thought we knew about X-ray images of the sun is out of date."

The X-Ray Telescope, or XRT, collects X-rays emitted from the sun's corona -- the outer layer of the sun that mystifies scientists in part because it is 100 times hotter than the sun's actual surface.

They hope the observations can help explain and perhaps predict space weather -- the ejections from the sun that can disable satellites, knock out electricity grids on Earth and cause the spectacular auroras in extreme northern and southern skies.

"Hinode images are revealing irrefutable evidence for the presence of turbulence-driven processes that are bringing magnetic fields, on all scales, to the sun's surface, resulting in an extremely dynamic chromosphere or gaseous envelope around the sun," said Alan Title, a physicist at Lockheed Martin Corp. and Stanford University in California.