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Science & Technology

Is the Earth's magnetic field about to flip ?

By T.K. Randall
May 1, 2018 · Comment icon 17 comments



Fortunately, it does not look as though the field will flip anytime soon. Image Credit: NASA / Peter Reid
In recent years, the magnetic field that surrounds and protects our planet has been gradually weakening.
A complete reversal of the field has happened several times before, with the last known instance occurring somewhere around 780,000 years ago.

The most recent changes had prompted suggestions that we could be in for another field reversal relatively soon, but now a new study has determined that this is actually quite unlikely.

As it turns out, today's field patterns match those that existed 49,000 years ago and 46,000 years ago when the magnetic field simply wobbled, but did not actually flip over completely.
While even a wobble can have some consequences (such as more intense solar storms), the disruption caused would be much less than if there was a total field reversal.

"There has been speculation that we are about to experience a magnetic polar reversal or excursion," said geomagnetism expert Professor Richard Holme from the University of Liverpool.

"However, by studying the two most recent excursion events, we show that neither bear resemblance to current changes in the geomagnetic field and therefore it is probably unlikely that such an event is about to happen."

"Our research suggests instead that the current weakened field will recover without such an extreme event, and therefore is unlikely to reverse."

Source: Live Science | Comments (17)


Recent comments on this story
Comment icon #8 Posted by cormac mac airt 5 years ago
It should be pointed out that the following is a bit misleading: While the Matuyama-Brunhes (AKA Brunhes-Matuyama) transition, revised to circa 770.2 ± 7.3 ka, was the last MAJOR occurrence it wasn't the last. There have since been others such as the following:  Stage 17 Geomagnetic Excursion - circa 671 +/- 12 ka BP “Big Lost” Geomagnetic Excursion - circa 579?±?6?ka BP Pringle Falls Geomagnetic Excursion - circa 211,000 +/- 13 kya BP (Midpoints) Iceland Basin Geomagnetic Excursion - circa 192,000 BP – 189,000 BP Blake Geomagnetic Excursion - circa 116.5 ± 0.7 kyr BP - 112.0 ± 1.9 kyr BP Lasc... [More]
Comment icon #9 Posted by Socks Junior 5 years ago
But those were excursions, not reversals. Brief, and they went back.
Comment icon #10 Posted by cormac mac airt 5 years ago
Stage 17 Geomagnetic Excursion - circa 671 +/- 12 ka BP:  Another fully reversed ?ow, dated at671 ? 12 ka, gives new volcanic evidence for the Delta/Stage 17 excursion.  https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/jgrb.50214   “Big Lost” Geomagnetic Excursion - circa 579?±?6?ka BP:  One lava ?ow dated at 592 ? 20 ka has a fully reversed paleodirection and most likely erupted during the Big Lost excursion https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/jgrb.50214   Pringle Falls Geomagnetic Excursion - circa 211,000 +/- 13 kya BP:  It is presented here the obtained high-re... [More]
Comment icon #11 Posted by Socks Junior 5 years ago
An "aborted reversal" with "marked directional instability". That's the point! Certainly direction is a qualifier of reversal. However, time is just as certainly a qualifier. I quote from a number of paleomagnetic reference books, bolding is mine. Essentials of Paleomagnetism, Tauxe, 2010 Paleomagnetism: Continents and Oceans, McElhinny and McFadden, 2000 Geomagnetic Excursions, Laj and Channell, 2007 (from the book Treatise on Geophysics) The point is, a reversal proper indicates that the axial dipole field changes sign, and then stays that way for a significant period of time. During excursi... [More]
Comment icon #12 Posted by Socks Junior 5 years ago
I take your point that the field as temporarily reversed itself in the interim - the aforementioned excursions. I think it muddies the waters in a general consumption article to bring in the excursions. I don't think it's necessarily misleading to simplify the situation. I think this is an interesting discussion though!
Comment icon #13 Posted by cormac mac airt 5 years ago
As I see it a reveral is a reversal, regardless of duration. Your use of sources effectively blows excursions off as irrelevant IMO when we're actually talking durations of anywhere from 14+ human generations (the 440 year Laschamp Event, using 30 years per generation as a ballpark figure) to hundreds or even thousands of generations. Personally I find it intellectually dishonest overall, but then I'm looking at it from a human timeframe and not a geological timeframe.  Edit to add: By intellectually dishonest I'm referring to the original post and not your take on same.  cormac
Comment icon #14 Posted by Socks Junior 5 years ago
I think that is the main issue. The different timeframes. As I think I've said before, all my work is done hundreds of millions of years in the past. Because of that, the main focus is on averaging out these thousand-year timescale behaviors because (a) hard to find fine-scale records that far back and (b) to extract useful information about continental positioning we need stability of the geomagnetic field. These general-interest articles about reversals always end up in that weird gray area - because human timescales simply are less than rounding errors on almost all geologic information - y... [More]
Comment icon #15 Posted by Ogbin 5 years ago
I would just like to say that you guys are Super Smart. 
Comment icon #16 Posted by Not A Rockstar 5 years ago
yes, they are and classy in debating as well. I actually understood it all   thank you @Socks Junior and @cormac mac airt !!
Comment icon #17 Posted by Doug1029 5 years ago
It is about to flip.  But in geologic time, "about" can be a very long time. Doug


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