Night of the aurorae: The great solar storm of 1859.

solar flare pd

One hundred and fifty-six years ago today, on September 2, 1859, an unusual event took place 93 million miles away out in space but which had startling effects noticeable on Earth. On that day one of the largest solar storms ever recorded occurred. A geomagnetic event, popularly known as a solar storm, resulted in a gigantic solar flare that spewed a huge amount of charged particles through space which struck the Earth’s magnetosphere. This had a number of results quite visible on Earth. One of them was that aurora borealis and australis–the Northern and Southern Lights–were unusually widespread and visible at many places around the world. In addition to great dancing curtains of lights in the night sky, strange electrical effects were also recorded. Telegraph lines in some places wouldn’t function. Some telegraph operators actually got electric shocks when they touched their equipment. In other locales, operators reported they could still send messages even when their sets weren’t powered on. There was a lot of electricity humming that day, both on the ground and in the sky.

The intricacies of solar dynamics are pretty complicated, and I don’t pretend to understand them (though I do know they have nothing to do with climate change). Suffice it to say, astronomers, especially in Britain, noticed there was some unusual activity on the Sun a few days before the great storm. On August 28, an unusual number of sunspots were observed. One of the men doing the observing was a British amateur astronomer, Richard Carrington, who had spent several years at his home-built observatory in Surrey taking various observations of the Sun. At this time there were still a lot of odd theories about how stars worked. Carrington, like others before him, kept trying to determine the rotation of the Sun by watching sunspots, but like others was frustrated that it was very hard to pin down an exact figure for some reason. The reason, discovered in the 1860s by others working with Carrington’s data, was that the surface of the Sun behaved like a liquid, jiggling about sort of like the yolk of an egg, as opposed to being a fixed globe as everyone had previously supposed. Carrington didn’t know this yet in 1859, but he did observe the huge solar flare that occurred on September 1. His observations were corroborated independently by those of another British amateur astronomer, Richard Hodgson. The 1850s were a true golden age for gentlemen astronomers in Europe, although their observations and theories were often a bit bizarre by modern standards.

carringtons sunspots 1859

This sketch by Richard Carrington shows the configuration of sunspots he observed on September 1, 1859, just before the massive solar storm began.

In any event, the Sun was pumping out a bunch of stuff, and when it hit the Earth’s magnetosphere, people all over the world got a spectacular show. Aurorae were seen in places where they almost never had been before–there’s a famous story of miners in the Rocky Mountains being awakened by the lights in the sky and initially thinking it was morning. There were even some reports of aurorae being seen almost at the equator, which is virtually unheard-of. Some of these reports came from as far away as Senegal in West Africa and Hawaii in the central Pacific. We usually associate aurorae events with very high latitudes at the poles, but on September 2, 1859, the rest of the world got to see what the dwellers of Alaska, Siberia and the Falkland Islands got to see far more often.

The effects of the solar storm, though spectacular, were thankfully not very problematic. Telegraphs were really the only significant electrical infrastructure that existed in 1859, and thus all of the bad effects we know about involve telegraph lines or equipment to one degree or another. Obviously this is no longer true. By the 1880s the United States and some countries in Europe began to develop electrical power systems; telephones were already in use, and by the middle of the 20th century a solar event like the 1859 solar storm would have played havoc all around the world. Today we’re even more susceptible, thanks to GPS satellites, cell towers and power stations, all of which could theoretically be affected by geomagnetic storms. If something like the 1859 storm happened again, probably most of us in First World countries would suffer power brownouts and perhaps cell service interruptions, but the economic losses could run into the billions of dollars. We have some protocols in place for such an event, but perhaps not as many as we need. Hopefully our phones would still have enough charge to take pictures of the epic Northern and Southern Lights that would result.

aurora pd

People all over the world were treated to a spectacular night light-show during the solar storm of 1859. 

The great solar storm of 1859 was an interesting anomaly in astronomical and scientific history. It cemented Carrington’s reputation; he won various awards for his astronomical work and in fact the 1859 storm is sometimes known as the Carrington Event. It’s more interesting to think about what it would be like if something like it happened again in our modern world. All life on Earth derives from the Sun, but sometimes it throws us a curveball too.

All images in this article are in the public domain.
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