Posted on 04/23/2003 2:23:08 PM PDT by RightWhale
Mystery of the Sun's Two North Poles
By Tony Phillips Science.NASA.gov
posted: 08:00 am ET 23 April 2003
Three years ago, something weird happened to the Sun.
Normally, our star, like Earth itself, has a north and a south magnetic pole. But for nearly a month beginning in March 2000, the Sun's south magnetic pole faded, and a north pole emerged to take its place. The Sun had two north poles.
"It sounds impossible, but it's true," says space physicist Pete Riley of Science Applications International Corporation (SAIC) in San Diego. "In fact, it's a fairly normal side-effect of the solar cycle." Every 11 years around solar maximum, the Sun's magnetic field goes haywire as the Sun's underlying magnetic dynamo reorganizes itself. The March 2000 event was simply a part of that upheaval. "The south pole never really vanished," notes Riley. It migrated north and, for a while, became a band of south magnetic flux smeared around the Sun's equator. By May 2000 the south pole had returned to its usual spot near the Sun's southern spin axis--but not for long. In 2001 the solar magnetic field completely flipped; the south and north poles swapped positions, which is how they remain now.
Using a supercomputer named Blue Horizon and data from spacecraft (especially NASA's ACE and ESA-NASA's Ulysses) Riley and colleagues are studying how these complex changes can affect our planet. "The Sun's magnetic field permeates the entire solar system," explains Riley. "It interacts with Earth and is the primary driver of space weather."
The vast region of space filled by the Sun's magnetic field is called the heliosphere. All nine planets orbit inside it. But the biggest thing in the heliosphere is not a planet, or even the Sun. It's the current sheet--a sprawling surface where the polarity of the Sun's magnetic field changes from plus (north) to minus (south). "We call it the 'current sheet,'" says Riley, "because an electrical current flows there, about 10-10 amps/m2." The filament of an ordinary light bulb carries sixteen orders of magnitude more amps/m2. But what the current sheet lacks in local amperage, it makes up in sheer size. The sheet is 10,000 kilometers thick and extends from the Sun past the orbit of Pluto. "The entire heliosphere is organized around this giant sheet."
Ordinarily, the current sheet circles the Sun's equator like a wavy skirt around a ballerina's waist. But during the double north pole event of March 2000, the current sheet was radically altered: The waviness increased. Irregularities appeared. Its topology "morphed" from a ballerina's skirt to a giant seashell.
(Excerpt) Read more at space.com ...
The monopoles were revolting.
Tutu much!
When I realized that your ships had monopole detector's I knew that you could find my Bussard Ramjet. That's when I abandoned the drive section and hid on the 4th planet with the native I had captured and my supply of tree of life seeds. Tapping into your internet via tight beam has kept me amused :>
(goodness I hope you read Niven and will get the joke, otherwise I must look like a loon)
Yup. lol
At one point or another, I've read everything Larry's every written. Your joke was most amusing, O' greatest of the Pak Protectors.
Any word on when Ringworld is coming to the big screen? I'd heard the project was more or less dead.
last I heard was the debacle where Niven didn't know that James Cameron's interest was supposed to be secret and he mentioned it at a Con. That blew up in his face and the word was that Cameron dropped the idea. Since then Niven has been very tight lipped, though he has made generic comments about no one licensing his works to make a movie or TV out of them in a recent web chat. I'd love to have SciFi start to make Dune mini-series like films out of Known Space tales. It could be turned into episodic TV if they want, or just done when they get in the mood. If it takes off Ringworld or the Man Kzin wars wouldn't be far behind.
Well, he doesn't look right, but he seems to be responsding to the root, so I'll just have to wait and see. In the meantime, do you have any extra water I could spread around in the sand here?
Clearly one of my favorite authors, especially in terms of exploring ideas. I love the collections of Known Space where he intersperses stories with essays on the reality of the science he's just been using in the story. When he and Pournelle work together the books are more fun to read (a little more blood thirsty?).
Of course, my favorite by Niven is not a story, but an essay: Man of Steel, Woman of Kleenex. What's amazing about it is that, after setting up the joke, he follows through on all the logical consequences. He actually thought it all the way through!
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