Copyright The New York Times
People as far south as Alabama and New Mexico were treated to dazzling views of the northern lights on Wednesday as blasts of charged particles from the sun reached Earth. National Weather Service offices across the United States, including Oklahoma, Washington State, Tennessee, Iowa, Idaho and South Dakota posted images on social media of red and green lights stretching across the night sky. The aurora started to appear late Tuesday after the sun emitted masses of charged particles that travel with their own magnetic fields, a phenomenon called coronal mass ejection, or C.M.E. When these particles reach Earth, they disturb the planet’s magnetic field — a geomagnetic storm — and also cause lights, or aurora, to appear. The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center said three such ejections took place in recent days. “Two of these have already arrived, and they packed quite a punch,” said Shawn Dahl, a service coordinator at the Space Weather Prediction Center in Boulder, Colo. Mr. Dahl said in a social media video on Tuesday night that the third was the most energetic and strongest of the solar ejections, and that forecasters will be looking for its arrival around midday in the United States on Wednesday. The Space Weather Prediction Center has labeled the current geomagnetic storm watch as G4, the second-most severe kind on NOAA’s scale, with G5 being the strongest. Space forecasters have warned that these solar ejections do more than just put on a beautiful light show at night. They can cause problems in the power grid, including voltage problems, and also affect satellite operations, according to the Space Weather Prediction Center. GPS navigation may be degraded, it said. Space forecasters in Canada and Britain have also issued geomagnetic storm warnings because of the recent solar activity.
