How’s this for the plot of a new disaster movie – the earth’s magnetic field begins to weaken, and then flips completely. The result? Flash floods, earthquakes, meteor showers and other natural and cosmic calamities, none of which prevent Tom Cruise from getting his family to safety. Title: Field of Screams. The idea is less far-fetched than most epic blockbusters – in fact, it may be actually happening right now. However, unlike our special effects-laden Hollywood version, there is no cause for alarm. The earth’s magnetic field has flipped before and it will flip again.
Scientists now have geologic data that goes back more than 100 million years, and in that time the magnetic polarity of the earth in the northern hemisphere has reversed about 170 times. It’s not a change you can set your clocks by – the periods between flips can stretch anywhere from 200,000 to 1 million years. The last one took place about 780,000 years ago. That was before the Internet, which is why you never heard about it. A weakening of the planet’s magnetic field always precedes each flip. While this sounds ominous, as that field provides protection from cosmic radiation, it never weakens to an extent that triggers concern. Data from the European Space Agency has shown that we are in a weakening period, which could mean another flip is imminent – imminent in this case meaning sometime in the next few hundred years. So no need to change your travel plans – life will go on after this change, as it did following all the ones that have already happened. Of course, that wouldn’t make a very interesting movie.
For more factual reading on this fun topic, we suggest:
- Wikipedia: https://en.wikipedia.org/wiki/Geomagnetic_reversal
- Scientific American: https://www.scientificamerican.com/article/earth-s-magnetic-field-flip-could-happen-sooner-than-expected/
- U.S. Geological Survey: https://www.usgs.gov/faqs/it-true-earths-magnetic-field-occasionally-reverses-its-polarity
- Space.com: https://www.space.com/space-mysteries-why-do-earths-magnetic-poles-flip
