Tourists usually have to pay big bucks and brave cold climates for a chance to see the aurora borealis, but last weekend many people around the world just had to look up to see these colorful displays dance across the sky.
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Normally banished to Earth’s poles, the auroras strayed as far as Mexico, southern Europe and South Africa on the evening of May 10, delighting sky watchers and filling social media with images of abundant pinks, greens and purples.
But for those tasked with protecting Earth from powerful solar storms like the one that caused the auroras, a threat lurks beneath the stunning colors.
“We have to understand that there is danger behind this beauty,” Quentin Verspieren, coordinator of the European Space Agency’s space safety program, told AFP.
Mike Bethue of the US Space Weather Prediction Center said “we are focused on the more ominous potential impacts” of solar storms, such as knocking out power grids and satellites or exposing astronauts to dangerous levels of radiation.
The latest auroras were caused by the most powerful geomagnetic storm since the “Halloween storms” of October 2003, which caused power outages in Sweden and damaged power infrastructure in South Africa.
There appears to be less damage from recent solar storms, although it often takes weeks for satellite companies to detect problems, Bettuy said.
There were reports that some self-driving farm tractors in the United States stopped when their GPS guidance systems went out due to the storm, he told AFP.
“Definitely not over”
These strange effects are caused by massive explosions on the Sun’s surface that shoot out plasma, radiation and even magnetic fields at incredibly fast speeds, born of the solar wind.
The recent activity comes from a sunspot cluster 17 times the size of Earth that has continued to rage through the week. On Tuesday, it erupted in the strongest solar flare seen in years.
The sunspot is facing the edge of the sun’s disk, so activity is expected to die down in the short term as its flares are directed away from our planet.
But in about two weeks, the sunspot will rotate back, once again turning its gaze toward Earth.
Meanwhile, another sunspot “is coming into view right now” which could cause “a lot of activity in the coming days”, ESA’s Space Weather Service coordinator Alexi Glover told AFP.
So solar activity is “definitely not over,” she added.
It’s hard to predict how strong these sunspots might be — or whether they might trigger new auroras.
But solar activity is just approaching the peak of its roughly 11-year cycle, so the chances of another major storm are highest “between now and the end of next year,” Bethui said.
What threat do solar storms pose?
Geomagnetic storms like the recent one create a magnetic charge of voltage and current, “essentially overloading” things like satellites and power grids, according to Bettwy.
The most famous example came in 1859 during the worst solar storm in recorded history called the Carrington Event.
In addition to the stunning auroras, the storm caused sparks to fly from the telegraph stations. The charge coming from the Sun was so strong that some telegraphs worked without being plugged into a power source.
So what would happen if such a powerful geomagnetic storm hit Earth again?
Bethui said most countries have improved their power grids, which should prevent long blackouts like those that hit Sweden in 2003 or Canada in 1989.
Still, he suggested people have an emergency kit in case the power goes out for a day or two. Fresh water can also help in the event that filtration plants go offline.
Astronauts are particularly at risk of radiation during extreme solar activity. People on the International Space Station usually find the best shelter they can when a severe storm is expected.
Bethui said a massive solar storm could expose astronauts to an “unhealthy dose” of radiation, but he didn’t think it would be lethal.
Stressing that he did not want to “scare fear”, Betwie added that radiation could also potentially “pass through the fuselage” of planes flying near the North Pole.
Airlines sometimes change their routes during extreme solar storms to avoid this, he added.
Several upcoming missions are expected to improve predictions of the Sun’s intense and unpredictable weather, with the goal of giving Earth more time to prepare.
(AFP)
