Get ready for a celestial spectacle, but also be prepared for potential disruptions! A massive burst of charged particles from the sun, known as a coronal mass ejection (CME), is set to slam into Earth on Thursday, October 10, triggering a ‘severe’ G4-class geomagnetic storm, according to the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center.
Storms of this magnitude can cause significant disruptions to our technological world. Power grids could experience outages, satellites might be knocked off course, and GPS navigation could face interference. NOAA warns that even critical infrastructure technology could be vulnerable to damage. But fear not, this cosmic event also promises a breathtaking display! The geomagnetic storm will make auroras, or the Northern Lights, visible at much lower latitudes than usual. According to NOAA, the mesmerizing celestial dance could be seen across the northern half of the United States, possibly as far south as Alabama and northern California.
The culprit behind this celestial show is an X 1.8-class solar flare, the most powerful type the sun can produce. These flares occur when tangled magnetic field lines on the sun violently snap back into place. Some flares, like this one, are accompanied by CMEs – fast-moving blobs of plasma that can take several days to reach Earth. Upon arrival, these CMEs can disrupt Earth’s magnetic field, resulting in the geomagnetic storms that cause technological malfunctions and those mesmerizing auroras.
NOAA measures geomagnetic storms on a scale of 1 to 5, with G1 storms considered ‘mild’ and G5 storms dubbed ‘extreme’. While there’s little individuals can do to directly prepare for this G4 storm, aurora chasers are advised to seek out dark skies, far from city lights, for the best chance to witness the celestial show. No special equipment is needed to see the auroras, but viewing them through a phone camera can enhance the vibrant colors.
This solar activity is not unusual, as the sun goes through an approximately 11-year activity cycle, with the peak known as solar maximum. The current cycle’s solar maximum was initially predicted to begin in 2025, but some scientists believe it may be happening right now. Researchers won’t know for sure until the maximum ends, and solar activity begins to decline again.
Besides Earth, another celestial object is also in the path of the incoming CME: the bright comet C/2023 A3 (Tsuchinshan-ATLAS), currently making its closest approach to the sun in 80,000 years. There’s a chance the comet’s tail could be blown off or bent by the solar eruption, similar to what happened to the ‘devil comet’ 12P/Pons-Brooks earlier this year. Skywatchers will have to wait until the comet emerges from the sun’s glare later this weekend to see if its tail survived this celestial encounter.
