Like many Victorian gentlemen of means, Richard Carrington did not need to sully himself with labor; instead, he turned his energies to the study of natural philosophy. It was the field of astronomy to which Carrington would apply himself, but unlike other gentlemen of similar inclination, he began his studies not as the sun set, but as it rose. Our star held great interest for Carrington, and what he saw on its face the morning of September 1, 1859, would astonish him. On that morning, as he sketched an unusual cluster of sunspots, the area erupted in a bright flash as an unfathomable amount of energy stored in the twisted ropes of the Sun’s magnetic field was released, propelling billions of tons of star-stuff on a collision course with Earth.
Carrington had witnessed a solar flare, and the consequent coronal mass ejection that would hit Earth just 17 hours later would result in a geomagnetic storm of such strength that it would be worldwide news the next day, and would bear his name into the future. The Carrington Event of 1859 was a glimpse of what our star is capable of under the right circumstances, the implications of which are sobering indeed given the web of delicate connections we’ve woven around and above the planet.
A Mortifying Spectacle
Solar science was in its infancy in 1859, and while Carrington’s instruments were crude by today’s standards — a 4-1/2″ equatorial mount telescope projecting an image onto a white card — it was enough. Using similar equipment, astronomers had begun to tease out the secrets of the Sun, observing that the number of sunspots and their location on the Sun’s face occur in cycles. They also knew that sunspots were associated with observable phenomena on Earth, such as the aurora borealis and aurora australis, and that there was a clear association between solar activity and the Earth’s magnetic field. Some solar observatories even had magnetometers that could record changes on Earth and correlate them to solar activity.
The event that Carrington was lucky enough to have watched unfold on September 1 was only one of many outbursts that the Sun would have over a multi-day period. Solar observers reported large numbers of sunspots starting on August 28, with strong aurora being seen at unusually low latitudes starting that night. That suggests that one or more of the sunspots had created a solar flare and coronal mass ejection (CME) of sufficient energy to fling a cloud of plasma toward Earth sometime in the prior two days — while the electromagnetic effects of a solar flare are visible about 8 minutes after it happens, the matter subsequently ejected takes several days to push through the 93 million miles (150 million km) of space between the Sun and the Earth.
Those eruptions would pale in comparison to what the Sun would release on September 1st. Carrington’s routine observation of the sunspot cluster that day was interrupted at 11:18 AM local time by the appearance of two intensely bright white spots of light that moved across the entire face of the sunspot before gradually fading out and disappearing. He at first thought something had happened to his apparatus and that direct sunlight was being projected on his viewing screen, but it became clear that he was witnessing something rare and unusual. He rushed to find someone else to witness the event, but when he returned a minute later was “mortified to find it was already much changed and enfeebled.” The whole thing lasted less than five minutes.
But the energy released in those few minutes would have enormous consequences. Gigatons of charged particles were blasted from the surface of the Sun, to ride along a twisted knot of the Sun’s magnetic flux on a collision course with Earth. That the first effects of the arriving CME were reported a mere 18 hours after Carrington saw the flare suggests that the previous solar flares had cleared the space between Earth and the Sun to make the plasma cloud travel faster than the usual million miles (1.6 million km) per hour; or perhaps the CME that arrived the night of September 2nd was in fact released by an earlier, unobserved solar flare.
Here Comes the Sun
No matter the source, the arriving beast caused a geomagnetic storm of epic proportions. The Earth’s magnetosphere was violently shoved aside, allowing charged particles to slip into the atmosphere and couple with gas molecules, producing strong aurorae. The lights were seen in both the northern and southern hemispheres at latitudes approaching the tropics; people reported being able to read a newspaper on the street at midnight and mistaking the bright display for sunrise and starting their days hours too early.
As awe-inspiring as the auroral displays were, they were but a backdrop to the destructive energy that was then sleeting down on the planet. As with the geomagnetic storm on 1989, the distortions of the Earth’s magnetic field eventually reached a point of collapse. NASA has a good simulation video of this, used as the image at the top of the article. The collapsing magnetic field released its stored terawatts of energy back into the Earth. With little in the way of electrical infrastructure, most of the current eventually dissipated harmlessly. But the nascent telegraph network would suffer the brunt of the damage. Telegraph offices reported outages and connection problems, switchgear crackled and sparked, and operators were shocked when they touched the keys. Some offices reported damage as paper tapes in the recording receivers burst into flames.
The storm continued for two days, damaging telegraph equipment across the globe. Some operators, in an attempt to spare their networks from further damage, disconnected their batteries from the lines, only to find that they could still send messages using only the current provided by the storm. Wires on poles coupled enough energy to light them on fire, and damage was considerable. By the time the storm was over, millions of dollars in damage had been inflicted upon the fledgling network.
So Much More to Lose
In the century and a half since Richard Carrington made his observation, solar scientists have studied the Carrington Event and searched ice-core and other records for evidence of similar storms hitting Earth. Everything found thus far pales in comparison to the fury of the 1859 storm. There have been far more near misses, of course. One, a “Carrington class” CME launched by a 2012 solar flare, missed intersecting with Earth in its orbit by a mere nine days.
Famed insurer Lloyd’s of London, a firm with much to lose in such an event, commissioned a study to estimate the impact of a Carrington-level event striking the Earth today. They knew the stakes were much higher, what with 160 years of wires, switches, repeaters, satellites, and radios added to our grid, not to mention our complete dependence on the services built upon that infrastructure. They concluded that we might possibly see up to $2.6 trillion in grid damage in the United States alone, with power outages lasting up to two years.