The North and South magnetic perch swop places every 300,000 years , in a unconscious process that takes as much as 5,000 year . But evidence from an ancient lava flow hint the pole were once make a motion 53 point per twelvemonth .
We ’re presently overdue for a rod reversal , and a particularly rapid shift could cause chaos for birds ’ migration rule and human navigational instrumental role . One reassuring thing is that , in general , perch shifts are very , very gradual , and a 5,000 class pass would be riotous but not ruinous for Earth with a picayune sensitive planning .
However , we ’ve found bits and pieces of evidence that suggest the Earth ’s magnetised playing area can move way , way more quickly . In 1995 , an ancient lava flow in Oregon held a magnetic pattern that suggested the terminal had once been moving six arcdegree a twenty-four hours , which is about 10,000 time faster than normal and quick enough to totally override the Earth ’s magnetized theater in just about one calendar month . A heap of scientists brush aside that as dead implausible , sealed there had to be some error .
Now another instance of accelerated reversal has been discovered in a preserved lava catamenia in Nevada . The rocks there point Earth ’s field strike 53 degrees in a year . If that pace was ceaseless , then the terminal would have reverse in well under four year . It ’s not quite the blazing fast speed of the original discovery , but it ’s still much , much faster than we ever would have expect .
Researcher Scott Bogue of Los Angeles ’s Occidental College says that ’s definitely a possibleness , but he also considered the choice that the overall movement of the celestial pole was much slower , with a rapid acceleration for a class in the heart of a much longer , pass out process . Either way , if such rapid shifts are possible , even likely , then we had better be ready for some minor pandemonium when the next reversal finally gets underway .
[ Geophysical Research LettersviaNew Scientist ]
GeologyMagnetic FieldsScience
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