Luminosity and Electricity in the Sky

An article by Phil Plait, the “Bad Astronomer” on reminded me that today (September 1) is the 155th anniversary of the observation of the solar flare that within a day would cause the Great Auroral Storm of 1859.

This interesting astronomical event is of special interest to me as it is recounted in my upcoming novel “To Rule the Skies”.

Richard Carrington, an English gentleman-scientist and amateur astronomer, was sketching sunspots at the observatory he built at his estate at Redhill, Surrey, part of a survey of sunspots that went back almost a decade. He noted two bright flares emanating from one particular group of sunspots.  As he watched, the flares moved across the surface of the spot, then disappeared.

Carrington's sketch of the sunspot observed on Sept 1., 1859.  Solar flares observed at points A & C moved to points B & D in 5 minutes.

Carrington’s sketch of the sunspot observed on Sept 1., 1859. Solar flares observed at points A & C moved to points B & D in 5 minutes.

It was later noted that Carrington’s observation coincided with a deviation in the Earth’s magnetic field measured at Kew Observatory. But more importantly, in the next few days, all hell broke loose in the sky.

Evident to anyone who ventured outside at night were the aurora borealis displays of unprecedented brightness. According to newspaper articles of the time,

“…on Sunday night the heavens were arrayed in a drapery more gorgeous than they have been for years…Such was the aurora, as thousands witnessed it from housetops and from pavements.” (New York Times).

“Luminosity and Electricity in the Sky. The heavens were brilliantly illuminated about midnight on Sunday in this neighborhood, says the Manchester Guardian, by a mass of white rays or streaks, completely suffused with a vapor of a pink or dark roseate hue, through which brightly shone the stars, presenting a most beautiful appearance, and being far more deeply coloured than the aurora borealis is to be seen in this region.” (London Morning Post)

Aurora could be seen as far south as Havana, Cuba, and in the Sandwich Islands (now known as Hawaii). In addition, compasses of some ships at sea veered violently from their proper orientation, making navigation impossible.

More spectacular was the effect that the aurora had on the only large-scale electrical system that existed in 1859—the telegraph. The immense magnetic fields caused by the charged solar particles interacting with the Earth’s magnetic field induced electric currents in the telegraph wires that were beginning to be strung across the landscape. (The first transatlantic telegraph cable was laid almost exactly a year earlier in August 1858, but failed after a month; it would not be until 1866 that a successful cable would connect Europe and America.) Sparks flew out of a telegraph key and set fire to nearby papers. One operator was stunned by a shock when his forehead moved too close to a ground wire. Telegraph operators found that they could disconnect from their batteries and send telegrams using only the auroral current induced in the cables. The operators between Boston and Portland, Maine sent telegrams for over two hours in this way before the aurora subsided.

These manifestations cemented the relationship between electricity and magnetism that the great British scientist Michael Faraday first discovered.  It has even been proposed that the Scottish physicist James Clerk Maxwell was inspired by the Great Auroral Storm to describe more mathematically the relationship between the two forces in his famous equations.

With such mayhem happening on Earth’s nascent electrical systems, what would happen if an solar storm of equal magnitude happened now? We almost found out. On July 23, 2012, a solar flare sent particles streaming out of the sun’s corona. Astronomers estimate that this solar storm was about as intense as the 1859 event. Fortunately for Earth, it was pointed away from us this time, so we dodged the solar bullet. What could have happened? Phil Plait’s article describes in more detail, but surely, many Earth-orbiting satellites would have been fried—no GPS, no Dish TV, no weather forecasts. The electrical grid would have trouble handling the additional current induced into the hundreds of thousands of miles of high-voltage wires strung in the US alone. Indeed, a much smaller solar storm in 1989 caused blackouts in Quebec when transformers were overloaded. It has been estimated that a solar storm of the magnitude of the 1859 event would cost the US economy several trillion dollars in damage.

History has given us a picture of what could happen.  It’s up to us to be prepared.


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