Americans have been treated to brilliant displays by the Northern Lights this spring. The rare spectacle, also known as the “aurora borealis,” is the result of strong solar flares firing out of the Sun that also disrupted GPS systems on farm equipment across the US. The flares in May originated from an enormous sun spot that has now rotated back around to face the Earth, putting us right in the path of more solar ejections.
The Northern Lights are typically confined to the far northern latitudes but were seen across all 50 states, including Hawaii, and even down into Mexico on May 10. The solar storm that caused the lights was one of the strongest in the last two decades. According to experts, we got lucky because it did very little damage.
Those that did experience disruptions included farmers that rely on GPS for autosteering and other precision systems. John Deere even advised customers to turn off tools using GPS and real-time kinematic (RTK) to prevent the tech from receiving conflicting signals from the geomagnetic storm.
May’s geomagnetic storm also caused shortwave radio outages as well as power and satellite signal irregularities. While the impacts last month were relatively minor, it may have been just a warmup for what’s headed our way over the next year or so.
Solar storms are picking up because the Sun is headed for what’s known as “solar maximum,” which is the peak of a roughly 11-year cycle when solar activity is at its highest. The lead up to the maximum is characterized by increasing sunspot activity, which power colossal solar flares and CMEs. When the effects of those ejections reach Earth, they can damage electrical power grids, disable satellites, disrupt radio communications and GPS navigation, and endanger astronauts.
Flares are classified according to their strength. The smallest ones are B-class, followed by C, M and X, the largest. Each letter represents a ten-fold increase in energy output.
C-class flares are too weak to noticeably affect Earth.
M-class flares can cause brief radio blackouts at the poles and minor radiation storms that might endanger astronauts.
X is the last letter but there are flares more than 10 times the power of an X1, so X-class flares can go higher than 9.
Within each letter class, there is a finer scale from 1 to 9, also representing a ten-fold increase in energy output.
On May 10, an active solar region (sun spot) produced 12 X-class solar flares across six days, which caused the auroras across the US as well as the GPS and radio signal disruptions. On May 14, on its final day before rotating behind the western edge of the sun, the sunspot produced the largest solar flare since September 2017 — clocking in at an X8.79-class.
The most powerful flare on record was in 2003, during the last solar maximum. It was so powerful that it overloaded the sensors measuring it. They cut-out at X17 and the flare was later estimated to be about X45, according to NASA.
Luckily, CMEs typically take several days to arrive at Earth, though for some of the most intense storms, they’ve been known to arrive in as short as 18 hours. Over the last decade, the US NOAA and other agencies around the globe have bolstered the accuracy of space weather forecasts and implemented warning systems on the impending danger from a solar barrage.
The NOAA’s Space Weather Prediction Center posts flare activity HERE. Updates include expected impacts to Earth, including possible satellite or communication system disruptions. SWPC also forecasts where the aurora might be visible, so be sure to regularly check the page if you want a chance at seeing the Northern Lights…maybe from your own backyard!
We are currently experiencing Solar Cycle 25 and According to NOAA’s Space Weather Prediction Center (SWPC), solar maximum could occur anywhere between late 2024 and early 2026. Others predict between mid-2024 and the end of 2025. (Sources: NASA, SWPC, Scientific American, Space.com)
