Carrington Event

Date: September 1, 1859 • Location: Rome, Italy

A powerful solar flare caused a coronal mass ejection that struck Earth a few hours later, generating the most intense geomagnetic storm ever recorded and causing bright aurorae visible in the middle latitudes.

The Carrington Event was the most intense geomagnetic storm in recorded history, peaking on 1–2 September 1859 during solar cycle 10. It created strong auroral displays that were reported globally and caused sparking and even fires in telegraph stations. The geomagnetic storm was most likely the result of a coronal mass ejection (CME) from the Sun colliding with Earth's magnetosphere.