Posted on 01/24/2008 2:28:44 PM PST by neverdem
Artist concept of Ulysses making a north polar pass. (Credit: NASA/JPL)
The Ulysses spacecraft today is making a rare flyby of the sun's north pole. Unlike any other spacecraft, Ulysses is able to sample winds at the sun's poles, which are difficult to study from Earth.
Ulysses has flown over the sun's poles three times before, in 1994-95, 2000-01 and 2007. Last week, solar physicists announced the first indications of a new solar cycle. Visiting the pole at this time may lead to new insights about solar activity.
"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."
Many researchers believe the sun's poles are central to the 11-year ebb and flow of solar activity. 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. Old magnetic fields sink beneath the polar surface 200,000 kilometers deep (about 124,000 miles), 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, Calif.
Each previous flyby revealed something interesting and mysterious. One puzzle has been the temperature of the sun's poles. In the previous solar cycle, the magnetic north pole was about 80,000 degrees Fahrenheit (more than 44,000 degrees Celsius), or 8 percent cooler than the south. The current flyby may help solve this puzzle because it comes less than a year after a similar south pole flyby in Feb. 2007. Mission scientists will be able to compare temperature measurements, north versus south, with hardly any gap between them.
Ulysses also 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.
Launched in Oct. 1990 from the space shuttle Discovery, Ulysses is a joint mission of NASA and the European Space Agency.
Adapted from materials provided by NASA/Jet Propulsion Laboratory.
Which lib celebrity is going to ask if they snapped a picture of the ice cap as the spacecraft flew over the pole?
The icecaps have melted offering further proof of globull warming.
Nah, the sun doesn’t affect the earth’s climate. It’s all that nasty, evil carbon. That’s what controls the whole thing, ya know.
If the Sun is going into a new solar cycle and the last solar cycle change was 12 years ago (year 1996) then can we expect a less active (i.e. hot) solar cycle?
“million miles per hour”
Aw shucks! That ain’t nothin’!
Ulysses has sent back detailed photographs of the Sun’s surface, confirming what scientists have long suspected - the intense heat radiated by the Sun is caused by hundreds of thousands of SUVs driving around on the surface of the Sun.
Its worse then that. Photos from the spacecraft showed NO POLAR BEARS!!!!
I blame Bush.
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