NASA discovers magnetic ropes which connect Earth to the SunDecember 12th, 2007 - 4:49 pm ICT by admin
Washington, Dec 12 (ANI): A fleet of NASA spacecraft has discovered the existence of giant magnetic ropes (a twisted bundle of magnetic fields), that connects Earth’s upper atmosphere directly to the sun, among other findings.
The discovery was a result of the analysis of the spectacular eruptions of Northern Lights called “substorms” and the source of their power.
“The satellites have found evidence of magnetic ropes connecting Earth’s upper atmosphere directly to the sun,” said David Sibeck, project scientist for the mission at NASA’s Goddard Space Flight Center. “We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras,” he added.
“THEMIS encountered its first magnetic rope on May 20,” said Sibeck. “It was very large, about as wide as Earth, and located approximately 40,000 miles (70,000 km) above Earth’s surface in a region called the magnetopause,” he added.
The magnetopause is where the solar wind and Earth’s magnetic field meet and push against one another. There, the rope formed and unraveled in just a few minutes, providing a brief but significant conduit for solar wind energy.
Among other findings, the mission known as THEMIS (Time History of Events and Macroscale Interactions during Substorms) observed the dynamics of a rapidly developing substorm, and witnessed small explosions in the outskirts of Earth’s magnetic field.
The discoveries began on March 23, when a substorm erupted over Alaska and Canada, producing vivid auroras for more than two hours. A network of ground cameras organized to support THEMIS photographed the display from below while the satellites measured particles and fields from above.
“The substorm behaved quite unexpectedly,” says Vassilis Angelopoulos, the mission’s principal investigator at the University of California, Los Angeles. “The auroras surged westward twice as fast as anyone thought possible, crossing 15 degrees of longitude in less than one minute. The storm traversed an entire polar time zone, or 400 miles, in 60 seconds flat,” he added.
Photographs taken by ground cameras and NASA’s Polar satellite revealed a series of staccato outbursts each lasting about 10 minutes. According to Angelopoulos, some of the bursts died out while others reinforced each other and went on to become major onsets.
THEMIS also has observed a number of small explosions in Earth’s magnetic bow shock.
“The bow shock is like the bow wave in front of a boat,” explained Sibeck. “It is where the solar wind first feels the effects of Earth’s magnetic field. Sometimes a burst of electrical current within the solar wind will hit the bow shock and we get an explosion,” he added.
Researchers expect to observe, for the first time, the origin of substorm onsets in space and learn more about their evolution. (ANI)
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