On 28 August 1859, British astronomer Richard Carrington noticed something unusual on the Sun. A flare, larger than anything he’d seen before.
Solar flare of 16 April 2012, captured by NASA’s Solar Dynamics Observatory. Image is red because it was captured at 304 angstroms. (NASA/SDO, public domain).
Three days later, Earth lit up. Aurorae erupted as far south as the Carribean. All hell broke loose in telegraph systems across the world. Lines began spraying sparks. Operators were electrocuted. Other telegraphs worked without being switched on.
Later, we figured it out. The sun ordinarily blasts Earth with a barrage of fast-moving protons and electrons; the solar wind. Most is deflected by the Earth’s magnetic field – particles are trapped by the field, forming the Van Allen radiation belts.
Flares add to this in two ways. The first is through intense electromagnetic radiation – a mix of X-ray frequencies produced by Bremmstrahlung, coupled with enhanced broad-spectrum radiation as a result of synchotron effects – both of them slightly abstruse results of relativistic physics. This strikes Earth, on average, 499 seconds after a major flare erupts in our direction. We’re safe on the surface from the effects; the Earth’s magnetic field and atmosphere stops even radiation on a Carrington scale. In 1859, nobody noticed. But today, astronauts on the ISS wouldn’t be safe. Nor would our satellites. So aside from the human tragedy unfolding in orbit, we’d lose everything associated with satellites – GPS to transaction systems to weather to Google Earth updates and everything else. Gone.
Buzz Aldrin on the Moon in July 1969 with the Solar Wind Experiment. (NASA/public domain).
It gets worse. Some flares also emit a mass of charged particles, known as a CME (Coronal Mass Ejection). Seen from the Sun, Earth is a tiny target in the sky. But sometimes we are in the way, as in 1859. The problem is that a CME hitting Earth’s magnetic field compresses it. Then the CME passes, whereupon the Earth’s magnetic field bounces back.
The bad juju is the oscillation, which causes inductiion on a huge scale. Induction is a principle of electromagnetics, discovered by Michael Faraday in September 1845 when he moved a conductor through a magnetic field, generating electricity down the conductor as long as it moved. It also works vice-versa – a moving magnetic field induces electricity in a stationary conductor. And electricity can be used to create magnetism. We’ve been able to exploit the effect in all sorts of ways. It’s how electric motors and loudspeakers work, for instance. Also radio, TV, bluetooth, ‘wireless’ internet broadband. Actually, pretty much everything. When inducing an electric current with magnetism, the strength of current is a function of (a) the size of the conductor, and (b) the flux of the magnetic field. Maxwell’s equations apply. The longer the cable, the more current generated in it. That’s how aerials work – like the one in your cellphone, ‘wireless’ router, laptop – and so the list goes on.
Now scale it up. Earth’s magnetic field moves, generating electrical current in all conductive material. Zzzzzzt! That’s why so much current was generated down telegraph lines back in 1859 – they were immense aerials.
Geothermal power station at Wairakei, New Zealand. This generates up to 13 percent of the North Island’s needs. Note the power lines – vulnerable to induced voltage in a Carrington event.
Fast forward to today. Heavy duty devices like a toaster or kettle don’t contain enough conductive material to induce voltage that will fry them during a CME event, and that’s true of most appliances – though your phone or computer might be damaged, because microprocessor chips and hard drives are vulnerable to very small fluctuations. Personally, if I knew a Carrington storm was coming, I’d unplug my computer at the CPU (the power cable acts as an aerial). But none of it will work afterwards anyway. Why? No mains power. That’s the problem – the power grid. Those 220,000 volt lines. They’re plenty big enough to suffer colossal induced voltages, as are the cable windings inside the transformers that handle them. Power grids around the world go boom.
Yes, we can rebuild the system. Eventually. Estimates suggest a minimum of five months in the UK, for instance, to get enough transformers back on line. Always assuming they were available, which they might not be if every other country in the world also wanted whatever was in stock. In any case, the crisis starts within hours. Modern cities rely on electrically pumped water. Feeling thirsty? Maybe you’re lucky enough to live near a river. You struggle through crowds dipping water. Struggle home with a pan of muddy liquid. No power – how do you boil it? You have a barbecue. What happens when the gas runs out?
Now think about everything that relies on electrically pumped water. Nuclear power stations. Their diesel generators are not designed to run for weeks or months. Think Fukushima. Over and over. I am SO GLAD I live in nuclear-free New Zealand.
This isn’t speculation. A CME-driven grid burn-out already happened to Quebec in 1989. Luckily the solar storm wasn’t colossal. Studies suggest that 1859 storms occur every 500 years or so, but we’re learning about the Sun all the time, and that may change. We had near-misses from dangerous CME’s in 2012 and earlier this year. We’re vulnerable.
A CME might not take down the whole planet. All depends on its size. But it could still do colossal damage. A study in 2013 put the potential cost of another Carrington storm at $US2,600,000,000,000. If you stacked 2.6 trillion US $1 notes, one on top of another, the pile would be 291,200 km tall, which is a shade over 75 percent the average distance of the Moon. That’s without considering the human cost. But there are ways to ameliorate the issue. Including shutting down the grid and disconnecting things if we get warning. If. The take home lesson? Remember the Carrington storm. Fear it.
If you want to read about how we might cope after a big CME, check out the novels by New Zealand author Bev Robitai. Sunstrike and Sunstrike: The Journey Home.
Copyright © Matthew Wright 2014