Extending out over 370,000 miles above the Earth, the magnetic layer known as the magnetosphere protects the planet from the charged particles of solar wind and cosmic rays that could tear away at our upper atmosphere, exposing us to ultraviolet radiation. That might seem like a permanent feature of the planet, and for the most part, it is. However, for the last 160 years, the strength of our magnetic field has been decreasing at an alarming rate. Known as the South Atlantic Anomaly, the diminishment is centered in a huge stretch of the Southern Hemisphere from Zimbabwe to Chile. The shield has grown so weak that it poses a danger for satellites that roam in that region. As we’ve discussed previously on the blog, Earth’s magnetic history can be studied by examining pottery from that time period. Geologists and archaeologists have determined that the pole reversals have a general pattern of one every 200,000 to 300,000 years. However, our last reversal occurred almost twice as long ago. That means we’re well overdue for a complete reversal of the Earth’s poles. What Happens When Poles Reverse The biggest fear with a pole switch is that the Earth will momentarily be left without a shield against space’s elements. While the magnetosphere could definitely weaken, there is no evidence that it has ever completely disappeared. Fossils from 781,000 years ago when the last reversal occurred show that the switch wasn’t catastrophic to life on Earth. The planet was rife with plants and animals and glacial records show that the reversal didn’t cause Earth’s axis or rotation to switch. The biggest harm to humans that could come from a complete pole reversal would be the disturbance to our technological devices. Flight would have to completely be reworked to compensate for the change, as would satellites and our ground-based electronic infrastructure. A pole reversal won’t bring with it apocalyptic volcanic activity but it will create a lot of inconveniences with our electricity and communication grids. Interested in learning more about how magnets impact the world around us? Head to our News & How-To’s section for tons of magnet related news and crafts.