This is part two of our brief series of explainers about the solar maximum and its effects on Earth. Read part one: “What’s all this about the solar maximum?”
Given we are headed into the maximum of Solar Cycle 25, which will see increased activity on the Sun, what does that mean for us down here on Earth?
While experts expect the solar maximum coming in 2024–25 to be moderate, increased solar activity — because of our reliance on technologies susceptible to disruption from solar storms — have caused a stir in recent months.
CMEs – huge ejections of the solar magnetic field – sometimes reach Earth and can disrupt electrical systems.
“CME events, which are more frequent during solar maximum, can have impacts on power lines, although we have mitigation these days which helps a lot,” Dr Marc Duldig, a physicist at the University of Tasmania, told Cosmos.
“Unwelcome electrical currents in our powerlines and internet cables can cause things to break, disrupting and risking lives (when power is out city-wide for days to weeks),” says Alister Graham, a professor of astronomy at Melbourne’s Swinburne University.
“You can have currents induced in metal pipelines – low range pipelines that carry water, oil or gas. These don’t cause sparking, but they degrade the welds in the joints, over time degrading the pipeline. Pipeline operators run reverse current to compensate,” Duldig adds.
Hundreds of satellites currently operate over our heads, supplying us with mobile communications and GPS technology vital for modern society.
“We’ve rapidly become more dependent on space-based technology,” University of Newcastle physicist Dr Hannah Schunker told Cosmos. “And we haven’t really gone through a full solar maximum with all this reliance. The repercussions of an event can be imagined, but the spreading of the consequences is virtually unknown.”
“If charged particles from the Sun enter the atmosphere, they can affect the ionosphere,” Schunker notes. “Changing the width of the ionosphere puts GPS satellites – which are above the ionosphere – measurements out, so they’re less accurate. Changing the density of the ionosphere can affect satellites in low Earth orbit at the lower side of the ionosphere. This can affect GPS and radio signals as well. You can lose signal from them altogether.”
Read more: Solar flare disrupts communications in Africa and Middle East, like flare which downed SpaceX satellites in February
But the experts are hopeful that major disruptions aren’t on the horizon during this solar maximum.
“Satellites can be damaged when their surfaces are charged up,” Duldig explains. “In a very bad storm, you might lose one or two satellites, out of the hundreds that are up there. You could be unlucky that could affect communication. But things are well mitigated these days, so it would have to be a very large storm and I don’t know that we’ll have that many.”
“The most vulnerable satellites are probably the geostationary ones that can be exposed directly to the solar wind,” says solar astrophysicist at the University of Sydney, Mike Wheatland. “There’s a stronger dependence on satellite infrastructure nowadays. But I think there’s some redundancy there.”
“Hopefully,” Graham adds, “the main impact in 2024/25 is just that those close to the poles notice more aurora in the night sky.”
Forecasting space weather
A major challenge when trying to predict solar storms is the complex nature of following volatility in our solar system’s central star.
“Solar storm prediction and real-time warning services are valuable,” Graham says. “They allow time (hours) for preventative measures, such as placing electronic equipment in safe mode, moving astronauts into the more protected part of their craft, temporarily shutting off power grids not yet equipped to handle the incoming electrical surge.”
But more time would make preparing for solar storms much easier and safer.
“We don’t really have much forecasting capability,” Schunker remarks. “We can observe a coronal mass ejection of the Sun in near real-time from observations of the sun. But we can’t predict how fast it’s moving or in which direction. If it is directed towards the Earth, we detect it at satellites. This gives us about an hour’s warning. Ideally, you would like a longer warning – 12 hours or a day.”
How can we possibly hope to ride the storm if the Sun were to send particularly strong solar winds our way?
Knowledge is solar power
The key is to observe the Sun and better understand the processes that lead to solar activity develop better predictions.
“The whole thing is driven by the sun’s magnetic field,” Schunker says. “Number one, you need to understand the sun’s magnetic field. Number two, you have to understand how it propagates in the solar wind: how fast it’s going and in which direction. The third thing you need to understand is how it’s going to interact with the Earth’s magnetosphere when it arrives.”
“The mission that has returned the greatest benefits is the Solar Dynamics Observatory that has been observing the sun continuously since 2010,” Wheatland says.
Meanwhile, the next generation of solar missions is already underway to deepen our understanding of our solar system’s central star.
“The Parker Solar Probe is at the Sun now, providing data to help scientists better understand the Sun and in turn provide better/earlier predictions of dangerous solar flares,” Graham adds.
“There is a risk from the sun in terms of big space weather storm that could cause damage at the Earth, satellite infrastructure, etcetera,” Wheatland notes. “I don’t think it’s something to keep people up at night.”