The Day the Sun Tried to Burn the Telegraph Down

The Mechanism

Richard Christopher Carrington was born in Chelsea, London, on May 26, 1826, the son of a wealthy brewer. After a brief unhappy stint at Cambridge studying for the clergy, he took the wealth from the family business and, in 1849, built himself a private astronomical observatory in the small Surrey town of Redhill, about twenty miles south of London. The observatory's central instrument was a 4.4-inch (113 mm) equatorial refracting telescope. Carrington's research program was systematic: he had decided, in 1849, to chart the positions and properties of every visible sunspot every day for as long as he could. By 1859 he had been doing this continuously for two years and produced what would become the first systematic Victorian sunspot atlas. The morning of Thursday, September 1, 1859, was bright and clear. At 11:18 a.m. local time, Carrington was at the eyepiece, projecting the solar image through the telescope onto a screen, sketching the configuration of the morning's sunspots in his standard format on a sheet of ruled paper. He had just finished drawing a large complex group of spots in the northern solar hemisphere, comprising about a dozen umbrae arranged in a kidney-bean shape across roughly 60 arcseconds. Without warning, in the dark region between two of the largest of the spots — that is, in solar tissue that should have been dark, not bright — there erupted a *blinding white-light flash*. Carrington's description, published in *Monthly Notices of the Royal Astronomical Society* later that year: *Within the area of the great north group ... two patches of intensely bright and white light broke out, in the positions indicated in the appended diagram by the letters A and B, and of the forms there given. My first impression was that by some chance a ray of light had penetrated a hole in the screen attached to the object glass.* He checked the screen. It was intact. He turned to his observatory clock to mark the time. By the time he turned back to the eyepiece, the two bright patches had moved — at a rate of about 5 arcseconds per minute — across roughly 35,000 miles of the solar surface, and were beginning to fade. The total duration of the event, in white light, was about five minutes. Carrington was the first person ever to have seen a *solar flare*; a second amateur astronomer, Richard Hodgson, watching the same sun from his observatory in Highgate at the same moment, recorded the same event independently. The two reports appeared back to back in *MNRAS* 20: 13-15 (November 1859). What Carrington did not know — and could not, in 1859, have known — was that the flash he had just observed was the *visible electromagnetic signature* of an enormous *coronal mass ejection* (CME): a magnetic bubble containing about 10¹² kilograms of solar plasma, accelerated to about 2,000 kilometers per second, hurled directly toward the Earth. The bubble took 17.5 hours to make the 93-million-mile journey to Earth's magnetosphere (the typical transit time for a solar storm is 2-3 days; this one was so energetic it cut the time by an order of magnitude). At approximately 5 a.m. UT on September 2, 1859, the CME hit. The Earth's magnetic field — normally a stable dipole pointing roughly south-to-north — was compressed, then violently reconfigured, then *reversed* in places. The aurora, normally confined to the polar regions, *bloomed* across nearly the entire night side of the planet. In the Rocky Mountains, gold prospectors woke before dawn to a sky so bright that they began preparing breakfast, believing it was sunrise. In Boston, the aurora was bright enough to read a newspaper by at midnight. In Hawaii, in Cuba, in central Mexico, in Honolulu, in Colombia, in southern Japan, in Queensland, in New Zealand — places that in normal times never see auroras — the sky was on fire. *The New York Times* of September 3, 1859, reported a "sublime panorama" overhead. But the storm did not stop at lighting the sky. The reconfiguring magnetic field induced *enormous* electric currents in any long conductor on or under the ground — and the longest conductors in 1859 were the recently-installed *telegraph lines* of Europe and North America. Telegraph operators across two continents reported sparks jumping from their instruments. In Pittsburgh, an operator was knocked unconscious by a single discharge. In Sweden, telegraph paper caught fire from sparks emerging from the receivers. The most extraordinary detail — recorded in the contemporary American Telegraph Company logs and reproduced in subsequent histories — is that operators at the Boston and Portland, Maine offices *disconnected their batteries entirely* and, for the next two hours, *continued to send and receive messages* using only the current induced in the telegraph wires by the storm in the air above their heads. The conversation, as recorded in the Boston-Portland exchange log: "Mine is also disconnected, and we are working with the auroral current. How do you receive my writing?" "Better than with our batteries on. Suppose we work without batteries while we are affected by this trouble." The exchange of about 200 words took place between 8:30 and 10:00 p.m. local time on September 2, 1859. It is the first recorded instance of a sustained telegraph conversation transmitted on naturally-induced atmospheric current. After about two hours the storm subsided. The telegraph lines were reconnected to batteries. The aurora faded over the following two nights. The storm — what we now call the *Carrington Event* — was the most intense geomagnetic storm ever recorded. The closest modern comparison is the March 1989 storm that knocked out the Quebec power grid for nine hours; the Carrington Event was, by every available proxy estimate (geomagnetic indices reconstructed from contemporary magnetometer readings, the auroral oval boundaries from contemporary newspaper reports), an event *3 to 5 times larger* than 1989. The implications for a modern technological civilization are sobering. Every continent-scale electrical grid on Earth contains long transmission lines and transformers; a CME of Carrington-magnitude would, by best current models, induce currents in those lines that exceed the design tolerances of the transformers; transformers would burn out across thousands of substations simultaneously; the resulting power outages would last not for hours but for months to years (large grid transformers are typically not stocked as spares and take 6-18 months to manufacture). A 2008 National Academies study estimated the cost of a present-day Carrington-class event at $1-2 trillion in the first year alone, with full recovery taking 4-10 years; the 2013 Lloyd's of London study put the figure at $0.6-2.6 trillion. The 2012 near-miss — a Carrington-magnitude CME emitted by the Sun on July 23, 2012, that missed the Earth by *9 days of orbital motion* — is the closest call we have had. Carrington himself died at his Redhill observatory on November 27, 1875, age 49, of an unidentified illness possibly involving a heart condition; his observations of the September 1, 1859 flare were the central published achievement of his career. A note about him added to the public record in 2026: in May of this year — three months before this writing — the Royal Astronomical Society archivist Kate Bond discovered, in a box of uncatalogued 1850s Carte-de-Visite photographs in the RAS basement, the *only known photograph* of Richard Carrington. He is in his early 30s, beardless, in a high collar, looking directly into the camera with mild surprise. The face that watched the sun explode in 1859 has, after a hundred and sixty-seven years of being a blank, finally returned.