New “sun shield” to defend against solar megastorms that could black out planet

A planned new “sun defence” system could buy Earth crucial minutes to switch off satellites and power grids before a blast of plasma from the sun burns them out - leaving the planet in the dark for up to five months.

The computer model designed by the University of Michigan could offer 20 minutes warning - enough time to turn off electrical transformers, and prevent Earth being plunged into darkness by plasma blasted from the sun.

Rather than a space-based system, the proposed measure relies on supercomputers being able to accurately predict the sun's behaviour.

“It would really be a disaster much worse than a major hurricane,” said the University’s Gábor Tóth. Toth says that rebuilding burnt out electrical substations can take up to five months - leaving huge areas without power.

Most solar storms are deflected by Earth’s magnetic field, but America’s space weather agency NOAA are aware that bigger storms are possible - and could have devastating consequences.

The last really severe solar storm was  in 1859, known as the Carrington Event, but it hit Earth before it was criss-crossed by powerlines and substations. It destroyed telegraph lines, and lit up the skies so brightly people could read at night.

A Lloyds study in 2013 predicted that the effects on our wired society would be far, far worse- costing at least £1.67 trillion, and devastating transport, communication, finance and even food supplies due ot the lack of refrigeration.


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“You can have eruptions like coronal mass ejections or solar flares, and these propagate all the way from the Sun to the Earth,” said Toth. “These power grids always operate on the edge, and if you put an extra load on, they can fail.”

In an extreme solar event, as Earth’s magnetic field moved, it would create its own currents in the high-voltage cables that carry electricity across hundreds of miles.

At substations, where transformers convert the electricity to lower voltages for delivery into cities and towns, that extra current would likely push transformers over the edge, burning them out.

The University of Michigan’s space weather forecast is built on solar physics - and aims to predict whether a geomagnetic storm will be a normal, weak one - or a stronger disturbance.

Because large transformers take between five months and five years to build, a modern version of that storm could mean prolonged, extensive blackouts.

Fortunately, crisis could be averted by reducing the voltage or switching off parts of the grid entirely.

Also, powering down satellites could prevent the crippling of communications systems.

Our current systems aren’t enough to protect satellites or power grids - hence America’s space weather agency is looking for a replacement.

Our first responder is a satellite n a small orbit around a point where the gravitational pull of the Sun and Earth are equal, roughly a million miles from Earth. This satellite, the Advanced Composition Explorer (ACE), measures the solar wind.

“When we start our model from this point, we are able to make quantitative predictions that are better than the empirical models,” said Tóth.

Using measurements from ACE, the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Centre has been making forecasts from statistics-based, or empirical, models for space weather. These models work reasonably well for estimating the strength of magnetic fluctuations on a global level within the range of space weather observed before.

However, these models cannot predict events outside their statistical comfort zones, like the 1859 storm, or where around Earth magnetic disturbances will occur.

NOAA put out a call for new forecasting systems - and in tests, Michigan’s came out top.

It still only gives an hour of lead-time for the ordinary solar wind or 20 minutes for extreme space weather. It’s just enough time to switch off transformers and satellites - but America’s military want more.

For the next big goal, Tóth would be happy to make predictions based on observations of the Sun’s surface. “That would give a lead time of one to two days,” he said. “That would be a huge step up.”