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Could a Magnetic Shield Protect Earth From Space Weather?

A bad geomagnetic storm would fry the electric grid and cripple civilization for years—a space shield is cheap by comparison

A triple solar flare recorded in April, 2017 (NASA/SDO)
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Life on Earth faces lots of potential calamities. There are extinction-level asteroids or comets buzzing around the sun, potential volcanic eruptions that could lead to years of winter, as well as manmade catastrophes like runaway climate change or nuclear Armageddon.

One scenario that doesn’t get as much attention, however, is the possibility of a massive solar flare. Though it won’t kill us, it could kill satellites, electric grids and set our civilization back several years and trillions of dollars. And as George Dvorsky at Gizmodo reports, with a new study researchers from the Harvard-Smithsonian Center for Astrophysics quantified just how much damage a large flare might do—and they’ve suggested a bold, but probably not impossible, way to protect ourselves from the whims of the sun.

Solar flares are releases of magnetic energy from the surface of the sun. If powerful enough, these flares, and a related phenomenon called a coronal mass ejection (CME), can reach Earth. Typically, Maddie Stone wrote for Gizmodo in 2015, even large solar flares are dissipated in the Earth’s ionosphere, which leads to an awesome aurora event. But getting hit by a CME, a cloud of plasma ejected from the sun, would be a different story. The plasma can interact with electrical currents in the upper atmosphere, creating large currents that could fry power grids and electrical devices on the planet’s surface and erase magnetic tape and other media.

It’s not just some far-off sci-fi fantasy either. As Stone reports, a suspected CME did hit Earth in 1859 during what's known as the Carrington event. During this event, a series of CMEs hit the planet, shooting electricity through telegraph wires that shocked their operators and set papers on fire. It also caused an aurora that could be seen as far south as Cuba.

Such an intense storm hasn't yet struck us again, but we haven't gone with out other solar weather. Just last month, the largest solar flare in a decade hit Earth, though luckily we did not also get smacked by a CME. 

The new paper, published on the pre-print server arXiv.org, predicts that a storm similar to the Carrington event occurring today or decades into the future would be catastrophic for more than a few telegraph operators. “We predict that within about 150 years, there will be an event that causes damage comparable to the current United States’ GDP of approximately $20 trillion, and the damage will increase exponentially at later times until technological development will saturate [i.e. when technological development finally starts to slow down and be globally distributed],” Avi Loeb, a physicist from Harvard and an author of the study, tells Dvorsky. “Such a forecast was never attempted before.”

To mitigate such a super solar-storm, Hannah Osborne at Newsweek reports, the researchers suggest placing some sort of shield between the Earth and the Sun that would deflect any massive flares or CME’s heading toward earth. The best solution, they conclude, is a magnetic shield that could attract and deflect the particles.

They don’t have blueprints for the gadget, but they suggest that a 105-ton, $100 billion shield should do the trick, likely something like an electrified copper loop roughly the size of our planet. While that sounds expensive, they argue its cost is much less than rebuilding the world’s power grid.  “This value is comparable to the total cost of the International Space Station, and is three to four orders of magnitude lower than the current world GDP, or the economic damage from a flare around 100 years henceforth,” they write.

Other researcher agree the threat is real, but don’t buy all of Lingam and Loeb’s  assumptions. “I agree completely that the risk and economic damage from solar eruptions is too large and should be mitigated—imagine the current situation in Puerto Rico but worldwide,” Oxford’s Anders Sandberg tells Dvorsky. “However, I was not convinced by their economic model at all... there seemed to be far too many arbitrary assumptions. In particular, the vulnerability of the world economy can both increase and decrease, for example, if we build a more modularized and resilient power grid.”

Even so, as our reliance on technology increases, solar weather poses an increasing risk. And government agencies are starting to take notice. Just last year, many agencies including the Department of Homeland Security, the Air Force, NASA and the White House came together with researchers for a symposium on space weather to begin the conversation on mitigating the threats. Even FEMA has recently added adverse space weather events to its monitoring efforts. Whether or not a space shield comes to fruition, talking about it is the first step toward protection. 

About Jason Daley

Jason Daley is a Madison, Wisconsin-based writer specializing in natural history, science, travel, and the environment. His work has appeared in Discover, Popular Science, Outside, Men’s Journal, and other magazines.

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