The Carrington Event: the solar storm of 1859
The Carrington Event was the most powerful solar storm in recorded history. On September 1–2, 1859, a huge eruption from the Sun hit Earth, lighting up the sky with auroras as far south as the Caribbean and knocking out telegraph systems across Europe and North America.
Key facts
| Date | September 1–2, 1859 |
|---|---|
| Named after | Richard Carrington, English astronomer |
| Flare seen | September 1, 1859, late morning in London |
| Travel time to Earth | About 17.6 hours |
| Auroras seen as far south as | Cuba, Jamaica, Hawaii, Colombia |
| Near miss | July 23, 2012 |
| Strongest recent storm | May 10–11, 2024 |
What happened in 1859
On the morning of September 1, 1859, the English astronomer Richard Carrington was sketching sunspots when two bright white patches flared up on the Sun for about five minutes. Another observer, Richard Hodgson, saw the same thing independently. It was the first recorded solar flare.
About 17.6 hours later, a huge cloud of magnetized solar plasma, a coronal mass ejection, slammed into Earth. Normally such clouds take two to four days to arrive. The geomagnetic storm that followed on September 1 and 2 is the strongest in recorded history.
What people saw
- Northern lights near the tropics. Auroras were seen as far south as Cuba, Jamaica, Hawaii and Colombia. In the Rocky Mountains, gold miners reportedly got up and made breakfast, thinking it was morning.
- Telegraphs went haywire. Operators across Europe and North America got electric shocks, sparks set paper on fire, and some lines kept working with their batteries disconnected, powered by the storm's currents alone.
What would happen today?
A storm the size of Carrington's would induce currents strong enough to damage high-voltage transformers, which take months to replace, and could cause long, wide blackouts. Satellites could be damaged, GPS could be degraded for hours to days, and radio communication disrupted. Studies by Lloyd's and the US National Academy of Sciences have put the cost in the trillions of dollars.
It nearly happened: on July 23, 2012, a Carrington-class eruption crossed Earth's orbit about nine days after Earth had passed that point. In May 2024, the strongest storm in two decades (the "Gannon storm") brought auroras to Florida, Mexico and northern India and nudged GPS-guided tractors off course, but it was still much weaker than 1859.
How we get warned now
Satellites such as SOHO and NOAA's solar monitors watch the Sun constantly. A coronal mass ejection usually takes one to three days to reach Earth, so forecasters can give power companies hours to days of warning to protect the grid. Precise time matters too: power grids, phone networks and stock exchanges all rely on GPS time, which is why they also keep atomic clocks as backup. Read how GPS uses time.
Questions people ask
What was the Carrington Event?
The most powerful geomagnetic storm on record, on September 1–2, 1859, caused by a huge solar eruption. It produced auroras near the equator and disrupted telegraph systems worldwide.
Why is it called the Carrington Event?
After Richard Carrington, the English astronomer who saw and recorded the solar flare on September 1, 1859, the first time anyone had observed one.
Could a Carrington Event happen again?
Yes. Storms of that size are thought to happen roughly once every century or few centuries. One narrowly missed Earth on July 23, 2012.
What would a Carrington Event do to the internet?
Undersea cables' powered repeaters and the power grid are the weak points. Large blackouts could take networks offline, and satellites and GPS could be disrupted, although fibre-optic cables themselves are not affected by the currents.
Was the May 2024 solar storm a Carrington Event?
No. It was the strongest storm since 2003 and caused auroras far south, but it was considerably weaker than the 1859 storm.
Last updated October 23, 2026.