The Sun's Magnetic Field is about to Flip


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The Sun's Magnetic Field is about to Flip

August 5, 2013:  Something big is about to happen on the sun.  According to measurements from NASA-supported observatories, the sun's vast magnetic field is about to flip.

 

"It looks like we're no more than 3 to 4 months away from a complete field reversal," says solar physicist Todd Hoeksema of Stanford University. "This change will have ripple effects throughout the solar system."

 

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A new ScienceCast video anticipates the reversal of the sun's global magnetic field.

 

The sun's magnetic field changes polarity approximately every 11 years.  It happens at the peak of each solar cycle as the sun's inner magnetic dynamo re-organizes itself.  The coming reversal will mark the midpoint of Solar Cycle 24. Half of 'Solar Max' will be behind us, with half yet to come.

 

Hoeksema is the director of Stanford's Wilcox Solar Observatory, one of the few observatories in the world that monitor the sun's polar magnetic fields.  The poles are a herald of change. Just as Earth scientists watch our planet's polar regions for signs of climate change, solar physicists do the same thing for the sun. Magnetograms at Wilcox have been tracking the sun's polar magnetism since 1976, and they have recorded three grand reversals?with a fourth in the offing.

 

Solar physicist Phil Scherrer, also at Stanford, describes what happens: "The sun's polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity. This is a regular part of the solar cycle."

A reversal of the sun's magnetic field is, literally, a big event. The domain of the sun's magnetic influence (also known as the "heliosphere") extends billions of kilometers beyond Pluto. Changes to the field's polarity ripple all the way out to the Voyager probes, on the doorstep of interstellar space.

When solar physicists talk about solar field reversals, their conversation often centers on the "current sheet."  The current sheet is a sprawling surface jutting outward from the sun's equator where the sun's slowly-rotating magnetic field induces an electrical current.  The current itself is small, only one ten-billionth of an amp per square meter (0.0000000001 amps/m2), but there?s a lot of it: the amperage flows through a region 10,000 km thick and billions of kilometers wide.  Electrically speaking, the entire heliosphere is organized around this enormous sheet.

During field reversals, the current sheet becomes very wavy. Scherrer likens the undulations to the seams on a baseball.  As Earth orbits the sun, we dip in and out of the current sheet. Transitions from one side to another can stir up stormy space weather around our planet.

 

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A reversal of the sun's magnetic field is, literally, a big event.

 

That's an understatement. It'll be interesting to see what effects this will have on us. 

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I remember reading a few years back that they are expecting the Earth's magnetic poles to flip as well, or at least start to.  Now that would change some things!

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I remember reading a few years back that they are expecting the Earth's magnetic poles to flip as well, or at least start to.  Now that would change some things!

Just like in the movie 2012. I can't wait to have European weather in India. :P

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I remember reading a few years back that they are expecting the Earth's magnetic poles to flip as well, or at least start to.  Now that would change some things!

The magnetic poles on the Earth are constantly shifting.  The conspiracy theorists thought that they would magically flip instantly, but it doesn't work that way.

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This isn't that big a deal. It happens every 11 years or so. Hell, I've already lived through 2 such shifts. Nothing to see here, move along.

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is it gradual 'flip' or almost nearly instantaneous flip ?

It's a gradual shift over 11 years.  We're almost to the "zero" point, and when it passes that, it's considered "flipped".

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Just like in the movie 2012. I can't wait to have European weather in India. :p

 

You can't have it! It's mine! I love the UK's mild weather. I start to become very uncomfortable in anything above 25 degrees C. 

 

Which begs the question why am I going to Texas in September.

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Oh well scientists. They finally have something about space that isn't based on theory and they have to make it a big deal.

Err... you don't quite understand what a scientific theory is, do you?

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