A celestial spectacle could grace the skies of several northern U.S. states this week, as a geomagnetic storm watch has been issued for July 24. The Space Weather Prediction Center belonging to the National Oceanic and Atmospheric Administration has issued an alert to the public about the potential arrival of a coronal mass ejection (CME) from the sun, which could trigger the northern lights, or aurora borealis, as far south as New York.
The gigantic plume of plasma and magnetic field, the CME, was ejected from the sun on July 21 and is likely to reach Earth early on July 24. However, the exact timing is not certain. Space weather physicist Tamitha Skov said the storm could be delayed because of “slow solar wind ‘traffic’ & an additional glancing storm blow ahead of it.”
If they interact with the magnetosphere of Earth, then CMEs can cause a geomagnetic storm. During the storm, ions begin to interact with atmospheric gases, releasing energy in the form of light visible as the aurora borealis in the Northern Hemisphere and the aurora australis in the Southern Hemisphere.
NOAA scales geomagnetic storms from G1, minor, to G5, extreme. So, in this case, the watch is out for a G2-class storm. That would translate to a moderate-strength storm. Like warnings of this type, it’s not uncommon, and sometimes they turn out with nothing very significant happening. As the predicted date draws closer, forecasters will have a much better idea about what to expect from the CME.
According to the NOAA Space Weather Prediction Center, this may let the northern lights be seen to many of the states like Wisconsin, North Dakota, South Dakota, Michigan, Montana, Minnesota, and even the furthest northern parts of New York and Maine. The expected time window for its visibility has been forecasted to start from 01:00-04:00 EDT on July 24.
Though aurora enthusiasts are more than excited about the impending arrival of the CME, the prospective geomagnetic storm bodes ill for technology. On a general level, CMEs might further disrupt satellites, cause surges in power grids, and interject radio transmissions. High-energy particles in a CME can also cause damage to satellites in space and increase atmospheric drag, which in turn can impact satellite orbits. Astronauts in low Earth orbit also face increased radiation exposure during such events.
For information on new developments in space weather, NOAA’s Space Weather Prediction Center continues to provide the best source for alerts and forecasts.
With the skies priming for a potential luminous spectacle, the dual nature of CMEs—both awesome and potentially disruptive—profiles an intricate dance between our planet and the Sun.