Thursday, September 5, 2013

A one-two punch from the Sun in 1859

The impact of space weather was dramatically demonstrated approximately a century before the United States launched their first satellite into space when awe-inspiring auroral displays were seen over nearly the entire world on the night of Aug. 28-29, 1859. In New York City, thousands watched “the heavens . . . arrayed in a drapery more gorgeous than they have been for years.” The aurora witnessed that Sunday night, the NewYork Times told its readers, “ will be referred to hereafter among the events which occur but once or twice in a lifetime.” Even more spectacular displays occurred on Sept. 2. For residents of Havana, Cuba, the sky that night “appeared stained with blood and in a state of general conflagration.” Earth had experienced a one-two punch from the Sun, the likes of which have not been recorded since. From Aug. 28 through Sept. 4, auroral displays of remarkable brilliance, color, and duration were observed around the world, as far south as Central America in the Northern Hemisphere and as far north as Santiago, Chile, in the Southern Hemisphere.

Even after daybreak, when the auroras were no longer visible, disturbances in Earth’s magnetic field were so powerful that ground-level magnetic field monitoring sensors were driven off scale. Telegraph networks in many locations experienced major disruptions and outages. In several regions, operators disconnected their systems from the batteries and sent messages using only the current induced by the aurora. In fact, telegraphs were completely unusable for nearly eight hours in most places around the world.

Humanity was just beginning to develop a dependence on high-tech systems in 1859. The telegraph was the technological wonder of the day. There were no high-power electrical lines crisscrossing the continents or sensitive satellites orbiting Earth, both of which are vulnerable to events of the sort that disrupted telegraph systems in the 19th century. There certainly was not yet a dependence on instantaneous communication and satellite remote imaging of Earth’s surface. Now, in the early part of the 21st century, as the Sun is ramping up its activity in solar cycle 24, decision makers are asking: Has there been adequate preparation for severe space weather events, and what might be the consequences of worst-case events like that of the storm of 1859?

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