NASA spacecrafts flyby of Suns North Pole to unravel solar activity mysteriesJanuary 15th, 2008 - 4:52 pm ICT by admin
Washington, Jan 15 (ANI): Ulysses spacecraft - a joint mission of NASA and the European Space Agency, is making a rare flyby of the Suns North Pole, from where it would be able to collect sample winds that may lead to new insights about solar activity.
Solar physicists have already announced the first indications of a new solar cycle, which makes this flyby all the more significant.
“This is a wonderful opportunity to examine the sun’s north pole within a transition of cycles,” said Arik Posner, Ulysses program scientist at NASA Headquarters in Washington. “We’ve never done this before,” he added.
Many researchers believe the sun’s poles are central to the 11-year ebb and flow of solar activity.
First of all, when sunspots break up, their decaying magnetic fields are carried poleward by vast currents of plasma. This makes the poles a sort of graveyard for sunspots.
Also, old magnetic fields sink beneath the polar surface 200,000 kilometers deep, all the way down to the sun’s inner magnetic dynamo, which generates the solar magnetic field. There, dynamo action amplifies the fields for use in future solar cycles.
“Just as Earth’s poles are crucial to studies of terrestrial climate change, the sun’s poles may be crucial to studies of the solar cycle,” said Ed Smith, Ulysses project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California.
Each previous flyby has revealed something interesting and mysterious.
For example, Ulysses discovered the sun’s high-speed polar wind. At the sun’s poles, the magnetic field opens up and allows solar atmosphere to stream out at a million miles per hour. By flying around the sun, covering all latitudes in a way that no other spacecraft can, Ulysses has been able to monitor this polar wind throughout the solar cycle and has found that it is acting a bit odd.
“Twelve years ago, just before the previous ’sea change’ between solar cycles, the polar wind spilled down almost all the way to the sun’s equator. But this time it is not The polar wind is bottled up, confined to latitudes above 45 degrees, ” said Posner.
Another puzzle has been the temperature of the sun’s poles. In the previous solar cycle, the magnetic north pole was more than 44,000 degrees Celsius, or 8 percent cooler than the south. The current flyby may help solve this puzzle by comparing temperature measurements, north versus south, with hardly any gap between them.
Ulysses has flown over the sun’s poles three times before, in 1994-95, 2000-01 and 2007. (ANI)
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