The Solar storm of 1859—known as the Carrington Event—was a powerful geomagnetic solar storm during solar cycle 10 (1855–1867). A solar coronal mass ejection hit Earth's magnetosphere and induced one of the largest geomagnetic storms on record, September 1–2, 1859. The associated "white light flare" in the solar photosphere was observed and recorded by English astronomers Richard C. Carrington (1826–1875) and Richard Hodgson (1804–1872).
Studies have shown that a solar storm of this magnitude occurring today would likely cause more widespread problems for a modern and technology-dependent society. The solar storm of 2012 was of similar magnitude, but it passed Earth's orbit without striking the planet.
From August 28 to September 2, 1859, many sunspots appeared on the Sun. On August 29, southern auroras were observed as far north as Queensland, Australia. Just before noon on September 1, the English amateur astronomers Richard Carrington and Richard Hodgson independently made the first observations of a solar flare. The flare was associated with a major coronal mass ejection (CME) that travelled directly toward Earth, taking 17.6 hours to make the 150 million kilometre (93 million mile) journey. It is believed that the relatively high speed of this CME (typical CMEs take several days to arrive at Earth) was made possible by a prior CME, perhaps the cause of the large aurora event on August 29, that "cleared the way" of ambient solar wind plasma for the Carrington event.