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Surprising Science

Earth’s Magnetic Field Long Overdue For A Flip

It's been 800,000 years since the last one, and the field's been thinning for the last 150 years, so one space agency is launching measurement satellites.

Article written by guest writer Kecia Lynn

What’s the Latest Development?

Next month the European Space Agency plans to launch three satellites into orbit, and the data collected from them will give scientists insights into the state of the magnetic field, which they fear could come close to disappearing in less than 500 years, prior to reversing itself completely. As it stands today, the field has been thinning over the last 150 years, and ongoing changes will affect everything from drilling to GPS systems to animals’ ability to navigate.

What’s the Big Idea?

It’s not as though the magnetic field hasn’t reversed before. “[T]he geological record suggests the magnetic field has reversed every 250,000 years, meaning that, with the last event 800,000 years ago, another would seem to be overdue.” Unlike Mars, which lost its magnetic field billions of years ago, Earth’s field has always managed to restore itself. Advances in scientific understanding are already helping to clear up some of the mysteries behind why and how the magnetic field flips, but “there are significant holes” that need filling.

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