The Carrington Event occurred in 1859, with its most intense effects on 1–2 September.
The event was the most powerful geomagnetic storm recorded in modern history. On 1 September, English astronomers Richard Carrington and Richard Hodgson independently observed an intense white-light solar flare while studying sunspots. A coronal mass ejection likely followed and reached Earth unusually quickly, probably in about 17.6 hours.
The resulting disturbance produced spectacular auroras at unusually low latitudes and severely disrupted telegraph systems. Telegraph equipment sparked, operators received shocks, and some lines carried messages even after their batteries were disconnected because geomagnetically induced currents supplied the electricity.
The name comes from Carrington’s observation, although the connection between solar activity and Earth’s magnetic environment was not yet fully understood. Modern scientists use “Carrington-class” to describe space-weather events of comparable extreme intensity. A similar storm today could threaten satellites, radio communications, navigation systems, and electrical grids.