EVENT ON THE HORIZON
Earth, September 1st, 1859. Colours flash through the night sky above New England, gold miners in the Rocky Mountains are woken by the brightness of the Northern Lights, visible as far south as the Caribbean. Telegraph operators across the world receive electric shocks from their equipment, which continues to operate, despite being disconnected from the power supply.
The Sun, August 31st, 1859. A complex system of magnetic field lines suddenly twists, releasing a large quantity of plasma into space. This takes 17 hours to cross the 150 million kilometres to the Earth, which is at just the right place in its orbit to be hit by what today we’d call a coronal mass ejection.
The largest geomagnetic storm on record, the Carrington Event caused widespread electrical disruption and power blackouts in an electrical grid that was primitive compared to today’s complex system.
Should it happen again, the consequences could be catastrophic. A 2013 research project from Lloyds of London and Atmospheric and Environmental Research in the United States estimated the cost to the US alone could be US$2.6 trillion.
At the peak of its activity, the Sun belches out as many as three coronal mass ejections every day. One only just missed us in 2012, and if it struck today, the damage would be incalculable.
What’s it all about?
In their day-to-day lives, our PCs and other electrical equipment are unlikely to come into contact with charged particles, but every now and then, the Sun reaches out to touch us. Protected in the Earth’s magnetic bubble, we don’t often notice the effects of the solar wind unless we live far enough north or south to see the aurora. Our Sun is, compared to other places in the Universe, a relatively placid, middle-aged star, but occasionally it can surprise us.
The Sun operates on an 11-year cycle. In 1859, it was approaching the middle of this cycle, the time of greatest activity. Astronomers, equipped with ever-improving
