The biggest geomagnetic storm in two decades, sparked by solar flares, caused dazzling lights displays in parts of Latin America overnight on Friday, including a rare appearance in Mexico.
In Mexicali, a desert city on Mexico’s northern border thousands of miles from the Arctic regions where the northern lights are common, gradients of pink and purple illuminated the night sky.
The civil protection agency in Mexicali’s state of Baja California said more auroras could be visible this evening.
In Chile, where the lights are known as Aurora Australis, or Southern Lights, local media and social media users shared photos of the sky in the city of Punta Arenas painted with reds and magentas.
Local media in Argentina reported similar hues illuminating the sky in the Patagonian city of Ushuaia.
Geomagnetic storms are caused when explosions of plasma and magnetic fields from the sun’s corona are directed at Earth, where they can trigger such aurora displays, according to the US National Oceanic and Atmospheric Administration (NOAA).
The geomagnetic storm is likely to continue through the weekend, the agency said.
More powerful solar storms are expected over the weekend, threatening possible disruptions to satellites and power grids.
Social media lit up with people posting pictures of auroras from northern Europe (where it is called Aurora Borealis, or Northern Lights) and Australasia.
“We’ve just woken the kids to go watch the Northern Lights in the back garden! Clearly visible with the naked eye,” Iain Mansfield in Hertford, England, told AFP.
That sense of wonder was shared in Australia’s island state of Tasmania.
“Absolutely biblical skies in Tasmania at 4am this morning. I’m leaving today and knew I could not pass up this opportunity,” photographer Sean O’Riordan posted alongside a photo on social media platform X.
The excitement spread across Europe and North America, from Mont Saint-Michel on the French coast to Payette, Idaho, where the sky shimmered with green light above the western US states.
The NOAA, in an update yesterday, said that “storming of varying intensity” will persist through at least today.
“The threat of additional strong flares and CMEs will remain until the large and magnetically complex sunspot cluster rotates out of view over the next several days,” it said. “There have been reports of power grid irregularities and degradation to high-frequency communications and GPS (Global Positioning System).”
Authorities notified satellite operators, airlines and the power grid to take precautionary steps for potential disruptions caused by changes to Earth’s magnetic field.
Elon Musk, whose Starlink satellite internet operator has some 5,000 satellites in low Earth orbit, described the solar storm as the “biggest in a long time”.
“Starlink satellites are under a lot of pressure, but holding up so far,” Musk posted on his X platform.
China’s National Centre for Space Weather issued a “red alert” yesterday morning warning the storm is expected to continue throughout the weekend and will impact communications and navigation in most areas of the country, state news agency Xinhua reported.
Unlike solar flares, which travel at the speed of light and reach Earth in around eight minutes, CMEs travel at a more sedate pace, with officials putting the current average at 800km (500 miles) per second.
The CMEs emanated from a massive sunspot cluster that is 17 times wider than our planet.
The Sun is approaching the peak of an 11-year cycle that brings heightened activity.
Mathew Owens, a professor of space physics at the University of Reading, told AFP that how far the effects would be felt over the planet’s northern and southern latitudes would depend on the storm’s final strength.
“Go outside tonight and look would be my advice because if you see the aurora, it’s quite a spectacular thing,” he said.
People with eclipse glasses can also look for the sunspot cluster during the day.
The NOAA’s Brent Gordon encouraged the public to try to capture the night sky with phone cameras even if they couldn’t see auroras with their naked eyes.
“Just go out your back door and take a picture with the newer cell phones and you’d be amazed at what you see in that picture versus what you see with your eyes.”
Fluctuating magnetic fields associated with geomagnetic storms induce currents in long wires, including power lines, which can potentially lead to blackouts.
Long pipelines can also become electrified, leading to engineering problems.
Spacecraft are also at risk from high doses of radiation, although the atmosphere prevents this from reaching Earth.
Nasa has a dedicated team looking into astronaut safety and can ask astronauts on the International Space Station to move to places within the outpost that are better shielded.
Following one particularly strong flare peak, the US Space Weather Prediction Centre said users of high-frequency radio signals “may experience temporary degradation or complete loss of signal on much of the sunlit side of Earth”.
Even pigeons and other species that have internal biological compasses could be affected.
Pigeon handlers have noted a reduction in birds coming home during geomagnetic storms, according to the National Aeronautics and Space Administration (Nasa)’s Jet Propulsion Laboratory.
The most powerful geomagnetic storm in recorded history, known as the Carrington Event after British astronomer Richard Carrington, occurred in September 1859.
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