On Thursday, September 1, 1859, a 33-year-old brewer and amateur astronomer named Richard Carrington climbed the stairs to his private observatory near London, opened the dome slit, and as was his habit on a sunny morning, adjusted his telescope to project an 11-inch image of the sun onto a screen. He was tracing sunspots on a piece of paper when, before his eyes, “two patches of intensely bright and white light” suddenly appeared amid one large sunspot group. At the same time the magnetometer needle dangling from a silk thread at London’s Kew Observatory began dancing wildly. Before dawn the next day enormous auroral displays of red, green, and purple illuminated the skies as far south as Hawaii and Panama. Campers in the Rocky Mountains, mistaking the aurora for sunrise, got up and started cooking breakfast.
The flare Carrington had observed heralded a solar superstorm—an enormous electromagnetic outburst that sent billions of tons of charged particles hurtling toward Earth. (Another amateur English astronomer named Richard Hodgson also witnessed the flare.) When the invisible wave collided with the planet’s magnetic field, it caused electrical currents to surge through telegraph lines. The blast knocked out service at several stations, but telegraphers elsewhere found that they could disconnect their batteries and resume operations using the geomagnetic electricity alone. “We are working with the current from the Aurora Borealis alone,” a Boston telegrapher messaged an operator in Portland, Maine. “How do you receive my writing?”
“Much better than with the batteries on,” Portland replied.