There are some alarming signs that the north and south magnetic poles are about to swap places, and such a change would have a massive and potentially catastrophic effect on the Earth. The invisible magnetic field that protects Earth from dangerous solar radiation is generated by the Earth’s core and anchored by the poles, but this field is constantly in shift.

The poles have swapped places many times in the Earth’s history, usually changing about every 200,000 to 300,000 years. It’s been nearly 800,000 years since it has happened, so we are certainly long overdue, although pole reversals often have irregular gaps and the huge time frame means we are unlikely to see it happen in our lifetimes. But the latest satellite data indicates that there is a tug of war at the core of our planet that usually precedes such a shift.

Were it to happen, it would have tremendous impacts on our modern civilizations, wreaking havoc on the electrical infrastructure that we rely on to live. But NASA believes the effects may be overstated by some.

“Scientists understand that Earth’s magnetic field has flipped its polarity many times over the millennia,” reads a 2011 NASA statement. “In other words, if you were alive about 800,000 years ago, and facing what we call north with a magnetic compass in your hand, the needle would point to ‘south.’ This is because a magnetic compass is calibrated based on Earth’s poles. The N-S markings of a compass would be 180 degrees wrong if the polarity of today’s magnetic field were reversed. Many doomsday theorists have tried to take this natural geological occurrence and suggest it could lead to Earth’s destruction. But would there be any dramatic effects? The answer, from the geologic and fossil records we have from hundreds of past magnetic polarity reversals, seems to be ‘no.'”