What’s Flipping the Earth’s Magnetic Field?

first_imgWhy has the earth’s magnetic field changed orientation in the past?  How often does it happen?  How long does it take?  Such questions arise from a story reported by New Scientist that claims, “Second super-fast flip of Earth’s poles found.”  This implies there was a first case – and that “super-fast” reversals are strange.    The article stated matter-of-factly, “The magnetic poles swap every 300,000 years, a process that normally takes up to 5000 years.”  But then it said that a reversal that went 10,000 times as fast was inferred from an ancient lava flow in 1995.  “Not many people believed it” at the time, but now, a second case has turned up in Nevada.  “Such fast flips are impossible, according to models of the Earth’s core, but this is now the second time that evidence has been found.”    Another statement in the article suggests, however, that inferring such reversals is not an exact science: “It may have been a burst of rapid acceleration that punctuated the steady movement of the field,” explained Now Bogue of the US Geological Survey, invoking the image of “punctuated equilibria” usually associated with biological evolution (12/19/2008, bullet 2).  But then another scientist offered an alternative explanation – the data in Nevada were local rather than global.  Either way, it’s an anomaly that defies a predictable, lawlike behavior of the field – and neither scientist offered a physical cause for the anomalies.William of Ockham taught that entities should not be multiplied without necessity.  Scientific explanations become dubious when ad hoc conditions must be added to otherwise lawlike behavior.  If the field reverses like clockwork, as the article claims, why would it occur 10,000 times as fast on occasion?  And wouldn’t local effects call into question the whole inference of regularly-timed global reversals built on measurements of local fields?  How, then, can New Scientist claim that we are overdue for another reversal that “would cause widespread chaos – for navigation and migratory birds”?  It appears geophysicists know less about this subject than they claim.    As an alternative explanation, consider the theory of Dr. Russell Humphreys that invokes a single cause to explain all the effects: a catastrophic global flood.  This theory, that made predictions confirmed by Voyager 2, is explained by Jonathan Sarfati at Creation.com along with answers to skeptics’ objections.  Which theory would Ockham prefer?  (See Jan 2010 Scientist of the Month.)(Visited 8 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img

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