Solar storms are not even in my list of top five threats to humankind (nuclear war, asteroid strikes, super-volcano eruptions, a supernova within 30-50 light years, and intergalactic pirates), but they are still worth talking about because there may be an easy way to protect ourselves from the worst effects of solar storms.
Nobody knew anything about such storms until 200 years ago, when a big one scrambled all long-distance communications. But the technology was new then (electric telegraphs and the batteries that powered them) and electricity had few practical uses. The solar storm was just a transitory nuisance, not a global disaster.
It became known as the Carrington Event, after Richard Carrington, the British astronomer who witnessed the solar storm, a ‘coronal mass ejection’ from the Sun, on September 1, 1859. Thinking laterally, he linked it to the global electrical outage that happened a few hours later. It stirred interest in the scientific community, but little in the rest of the world because power grids, light bulbs and electric motors had not yet been developed. Now, however, electricity is indispensable in every industrial, commercial and domestic activity, and it turns out that these Carrington-like events happen quite often.
They vary in size. There hasn’t been one as big as the 1859 monster since then. However, smaller ‘mass ejections’ are blasted out of the Sun two or three times a day during the peak phase of the 11-year sunspot cycle, and most of them are travelling in or close to the ecliptic (the plane of the Earth’s orbit).
Even at Solar Maximum, only one or two per month hit our planet, because we are a moving target. The ones that hit just cause brighter Northern/ Southern Lights and interfere with radio transmissions. The biggest one was in 775 AD, when we know (from carbon-14 isotopes trapped in the rings of ancient trees) that a solar storm 10-100 times more powerful than the 1859 one hit our planet. No harm done, because no electricity under human control. Now it would be a catastrophe, even if it were only the same strength as the CE.
When massive solar storms smash into the Earth’s magnetic field, they deliver energy and charged particles that scramble satellite electronics. They may even bring satellites down by heating and expanding the stratosphere upwards into their orbits. On the ground, huge electrical currents surge through power grids and transformers, often not just knocking them offline (fixed within a day or two) but burning them out (one or two years to replace them).
No internet, no GPS. An eight-billion-strong world trying to cope with surviving pre-1940 technologies, probably on the brink of famine, while it struggles to rebuild a 2020s world. Not a terminal disaster, but you’d pay a lot to avoid all that. What kind of protection could you buy?
Here come the scientists with an idea called StormWall, and they’re not even asking for money. The idea, published this month in Space Weather, is that humans can reduce the impact of incoming geomagnetic (solar) storms on Earth by more than half by releasing huge canisters of a neutral gas (lithium, barium or sodium) or even plain salt water.
Six heavy-lift rockets (Musk’s Starship or China’s Long March 9) would lift the canisters into a geosynchronous orbit, 36,000 kilometres from Earth but still within its magnetic field. There they would wait, perhaps for years, until satellites spot a solar storm headed for Earth that is big enough to kill electrical and electronic devices.
Then they dump their load of around 400 tons of neutral gases into space, and sunlight will rapidly ionise it into a plasma that essentially absorbs much of the incoming energy (more than 50%). If everybody on Earth powers down at the same time to protect their devices, the damage could be relatively slight.
This is a brand new idea, so it will take a lot of work before everybody is happy, but the plasma does no harm and will disperse rapidly into space. All the technology involved is available now or in the very near future. As the co-author of the study, Daniel Welling, of the University of Michigan said: “It’s as if you could install an airbag in the magnetosphere.”
Gwynne Dyer’s new book is Intervention Earth