Is a polar reversal about to start?

There has been a growing scientific debate about a looming reversal of the earth's magnetic field – a flip of polarity which would switch the North and South poles.

But there's no need to worry it's not expected to start happening for a couple of decades – and it might take 1000 years to complete (but fossil remains have demonstrated that in the past, polar reversals have occurred within just a couple of years.

Magnetic reversals are triggered by Sunspot activity, the solar wind, and the interplanetary magnetic field induced primarily by the Sun.The Earth's geomagnetic field, is greatly influenced by solar effects. These include everything from disruptions in electronic or electromagnetic communications during heightened sunspot activity to minor shifts in our magnetic poles - which have been recorded at between. 8 and 10 degrees.

The effects of other planets' electromagnetic fields on the Earth are generally dismissed as insignificant in comparison to the solar effects. Major effects such as other planets causing or triggering magnetic pole reversals are not considered remotely possible. This is because  the solar wind dominates interplanetary space.

However, when the solar wind is temporarily interrupted, any planets' magnetosphere may significantly influence the electromagnetic properties of other planets.

During the periods of 'Sun-Jupiter oppositions', the Earth is directly between the Sun and Jupiter. Because of the differences in the inclination of the orbits of the two planets, such oppositions usually refer only to the longitudinal dimension—the latitudinal dimension is still considerably different, so  the Earth is not effectively in alignment with the Sun and Jupiter. Such alignment occurs only when the Earth passes between the Sun and Jupiter longitudinally, and simultaneously, the difference in latitude between the Earth and Jupiter is less than one minute of arc.  when such a near-perfect alignment does occur, the effects may be significant!

The concept suggested is that during a near-perfect alignment of the Sun, Earth, and Jupiter -- i.e. the longitudes of Earth and Jupiter are exact, and the differences in latitude within less than one minute of arc -- the “Jupiter Wind”, responds to the temporary cessation of the dynamic pressure of the solar wind (caused by the Earth's electromagnetic “shadow” falling on Jupiter's magnetosphere) by an electromagnetic surge in the direction of the null spot of the solar wind. This so-called Jupiter Wind consists of charged particles with negatively charged electrons leading the way and leaving the larger positively charged protons behind. The charged particles, no longer constrained by the pressure of the solar wind, are essentially flung out into space in the direction of the Earth.

The alignment is a dynamic event and the solar wind quickly reasserts its dominant pressure as the Earth moves out from between the Sun and Jupiter. For this reason, the charged particles reaching the Earth initially are electrons.  The leading edge of the Jupiter Wind would effectively sweep across the earth (just as the Earth's shadow swept across the face of Jupiter), causing a negatively charged surge, which when in combination with the solar wind could cause a massive electromagnetic force against the Earth's geomagnetic field. In many respects, the Jupiter Wind could provide the trigger and “reversing mechanism” while the solar wind provides the power.

The potential for such a geomagnetic pole reversal event ispredictable by simply calculating those dates when the Sun-Earth-Jupiter alignment is sufficiently precise to cause the shadowing effect.

Geopalenotologists rather glibly talk of such reversals occurring every million years or so. By their own data, however, such reversals have occurred, on average, every 400,000 years, and the last such reversal was 730,000 years ago. Logic suggests that the earth is overdue for a geomagnetic pole reversal.

More info: http://www.geomag.bgs.ac.uk/education/reversals.html


And here's some more from NASA:
http://www.nasa.gov/topics/earth/features/2012-poleReversal.html