The Carrington Event

Early in the morning of September 2nd 1859 the sky brightened and gold miners in Colorado got up and started cooking their breakfast. Gold miners get up with the Sun of course, at least the gold miners of that era. It wasn’t long before they noticed that while the sky was amazingly bright and colourful, this was no ordinary sunrise. It was no ordinary sunrise because the sun as nowhere to be seen. It was an Aurora, or Northern Lights, covering the entire sky, brighter than the full Moon.

And while the miners in Colorado got a particularly good view, people as far south of the Caribbean also saw spectacular Northern Lights, like nothing anyone had ever seen before. At least in recorded memory. And spectacular lights in the sky weren’t the only thing going on, all over Europe and North America telegraph systems burnt out, sparks were flying from telegraph poles, in some cases operators receiving shocks. And weirdest of all, there were some reports of telegraph systems that continued to operate, after they had been cut off from their power supply. What the hell was going on here?

What was going on was that the day before an astronomer by the name of Richard Christopher Carrington had seen the largest Solar Storm ever recorded on the Sun. They had in fact seen a Coronal Mass Ejection launched towards the Earth, a journey it made in 18 hours. Normally it takes several days, but a previous CME had cleared the way. The Sun was in an usually active period. And while they couldn’t actually see the CME, Carrington realized that the events unfolding on Earth were indeed related to what he had seen on the Sun, and he catalogued and recorded the effects of this event world wide. Thus it was named after him.

So how often do events like this happen? Fortunately science can answer that, such events are recorded in Arctic and Antarctic ice cores, and they show that similar events happen about once every 500 years, with smaller but also powerful events occurring several times per century. OK, so there’s a small chance that we will get beautiful auroras for a few days, and our telegraph lines will stop working, who cares? No one uses telegraph lines anyhow. No big deal.

Sadly, very big deal. Very big deal indeed. The telegraph lines failed because the storm supercharged Earth’s magnetic field, which induced current in the long conductive telegraph lines. In fact any metal wire will have current flowing through it if one of these big storms hits. And what do we use that has metal wires?  Well, everything, but there’s two really big ones that are most vulnerable to this sort of event. Power grids are one of them, huge numbers of power grids could overload and fail. Think continent wide, or world wide, blackouts. Secondly, many satellites in orbit would be burned out. And as icing on the cake, radio communication would be severely disrupted or curtailed during the event.

Would it be the end of civilization? Of course not, for that we would actually have to have a civilization. Would it be the end of life as we know it? Naw, just some power outages. In fact since a smaller CME knocked out power in Quebec in 1989, efforts have been made to harden power grids against such events. And in fact the Sun is constantly monitored so that we would get warning of such an event, and more than likely be able to mitigate most of its effects.

Still, if one night there are incredible auroras and then the power goes out, you can astonish your friends by saying “Meh, a big CME just struck Earth. This means … we party till the power comes back on!”

(The above image is claimed as Fair Use under US copyright law. It’s not being used for profit, is central to illustrating the post, and I think it’s being used legally. It’s a NASA photo: Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) NASA Official: Phillip Newman Specific rights apply. NASA Web Privacy Policy and Important Notices A service of: ASD at NASA / GSFC & Michigan Tech. U. I got it from this APOD page. It’s an award winning photograph of the Northern Lights over a glacial lake in Iceland. My last thought is that there must have been similar events in history, where the only effect would have been stunning auroras in locations where no one had ever seen or heard of an aurora. One can only imagine what people thought of that.)