There ’s a renew interestingness right now in Earth ’s magnetic poles – specifically , whether or not they’reabout to flip , and what may happen . The consequences of this apparently rapid geomagnetic backflip may voice a little sinister , but do n’t worry : we ’re not sure when the next reverse will happen , and even when it does , the risks are n’t likely to be as scary as you may imagine .
Let ’s begin with the basics .
As Earth ’s liquidity , atomic number 26 - rich out core step by step cools , it sloshes around through colossal convection currents , which are also moderately heave by Earth ’s own gyration . Thanks to a quirkiness of physics known as the dynamo theory , this return a powerful magnetic field , with a compass north and south final stage .
Although99 percentof the magnetic Department of Energy stay within the magnetic core , the slithers that turn tail extend into quad , and spend most of its clip deflecting potentially baneful , atmosphere - stripping solar wind .
flop now , the magnetized north pole is precisely where you suspect it is ; the same goes for the magnetic south pole . Both represent locales in which the satellite ’s charismatic field of view isvertical , and at which point your ambit acerate leaf taste to point upward .
Throughout geological time , these magnetic pole have switched sides – a phenomenon known as a “ geomagnetic reversal ” . Although there are several hypotheses that attempt to explicate this , geophysicist are still a littleunsureas to why it happens . It ’s clearly something to do with turbulence and chaos within the metallic outer core , but the specifics have n’t been nab down yet .
Either way , the last time a complete reversal find was 781,000 long time ago ; knight the Brunhes - Matuyama reversal after its artificer , its path could be traced through volcanic rocks that , upon make , “ froze ” a phonograph recording of the planet ’s magnetized field arrangement in billet . Prior to this pointedness , today ’s magnetic north celestial pole was at the south celestial pole , and frailty versa .
There was a temporary changing of the guard 41,000 years ago , but this only caused a reversal of 250 year or so before “ normality ” was furbish up . In any case , over the last 20 million class , the perch have flipped once every 20,000 - 30,000 days .
NASA is at pain tostressthat turnabout are the norm , not the exclusion . They ’ve always happened , and always will .
The current bemusement stem from the fact that we ’re 20,000 class or so “ delinquent ” for a reversal , and it ’s true that Earth ’s magnetised field has been ( speedily ) damp by about5 percent per decadein recent time – a sign that a reversal is perhaps on its elbow room . This , however , does n’t mean a flip is “ imminent ” or “ soon ” in human lifetimes .
Even if a flip is come on , it won’thappenovernight . “ Paleomagnetic evidence suggests reverse take around 1,000 - 5,000 years or so , ” Associate ProfessorPhil Livermore , an expert on Earth ’s geomagnetic sphere at the University of Leeds , told IFLScience .
Another issue is that the 20,000 - class average is pretty incertain , and this has n’t adjudge throughout Earth ’s history . “ In terms of whether we are due for a reversal , it is not possible to say , ” Livermore added .
“ Although the strength of the dipole is currently decreasing , this behavior is not anomalous , ” based on the geological criminal record . “ Previous instalment of decay have not leave in a reversal , merely a ‘ blip ’ in the field specialty over prison term . ”
A reversal , or a universal weakening of the planet ’s magnetised field , does present some potential threats , especially if it gets as low as10 percentof its full metier before regenerating again .
Still , the risks are likely not to be severe . During the Brunhes - Matuyama reversal , we have intercourse from the fogey record that industrial plant and animal life was just all right . PerNASA , there was no noticeable change in geological action either , be that seismal , volcanic , or glacial . earthly concern ’s gyration remained steady .
“ The primary issue is what might materialise to our electrical infrastructure – satellite , power grids , and so on , ” Livermore noted . If dangerous space weather brings highly gumptious particles along with it apace and voluminously , they will have a far easier time getting into our standard pressure without a potent charismatic subject field .
Satellites within theSouth Atlantic Anomaly – a renowned magnetised field weak smirch – are already at a gamy endangerment of price .
The damage really depends on the severity of the quad weather ; if it ’s severe , and we ’re unprepared , it could leave in a few major , extended brownout at the surface . Biological biography , however , will belike be just fine . Animals relying on magnetoreception to navigate may be a shade bemused for a while , but that ’s likely to be it .
So do n’t worry too much . There ’s a lot of dubiety here , but we would n’t bet on a surprise apocalypse .
