The story
On the morning of September 1, 1859, the British amateur astronomer Richard Carrington was sketching a large group of sunspots at his private observatory near London when two patches of intense white light flared up within it. Another British observer, Richard Hodgson, saw it too. Carrington had witnessed a solar flare, the first one observed. A few minutes later it was gone. About 17 hours later, a vast cloud of charged particles that the flare had thrown out struck Earth's magnetic field.
On September 2, the sky glowed with auroras seen as far south as the Caribbean. Miners in the Rocky Mountains woke and began making breakfast, thinking it was dawn. The telegraph, then the world's high-speed network, went wild: operators got shocks, some stations sparked or caught fire, and in New England operators disconnected their batteries and kept sending messages for about two hours on the current of the aurora alone. Carrington noted the link between the flare and the storm, but said the coincidence might be chance.
Later work showed that a coronal mass ejection, a huge eruption of solar plasma, connects flares to geomagnetic storms. The 1859 storm remains the benchmark for extreme space weather. A similar storm today could damage power grids and satellites, which is why the Carrington Event is a reference scenario in space weather planning.
Why it mattered
- Provided the first observed solar flare and the first hint that solar eruptions affect Earth.
- Established a benchmark for the worst plausible space weather, used in planning for grids and satellites.
- Showed that the electric telegraph, an early global network, was vulnerable to the Sun.
- Helped launch the study of solar-terrestrial physics that now monitors the Sun from space.
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