Posted 1 September 2021 in Blog, Science, Space.

History shows just how disruptive solar storms can be. Although records from centuries ago indicate powerful solar storms, we can learn the most about how a solar superstorm might affect us today by looking at ones from the 1800s onwards, when we started becoming increasingly dependent on electrical systems.

There is more than one way to measure the intensity of a solar storm, but these are some of the most significant ones recorded over the last 200 years.


Special event: Space weather is one of the aspects studied by Space Situational Awareness (SSA) programmes, along with near-Earth objects and space debris. Find out more about SSA from industry experts in our RHEA Talk webinar on 5 October 2021.

September 1859

In 1859, Earth experienced what is widely thought to be the most powerful solar storm on record. The ‘Carrington event’ is named for Richard Carrington, who observed a huge solar flare the day before a solar storm caused aurora all over the world, gave shocks to telegraph operators and caused a fire that destroyed a transatlantic telegraph line. Subsequent analysis showed it included a series of localised substorms and probably took less than 18 hours to reach the Earth. Scientists and engineers believe that if it were to be repeated now, it would cause far greater disruption than any so far during the space and information ages.

November 1882

A geomagnetic storm caused a brilliant auroral display and what was described as an ‘auroral beam’ by observers in the UK. There were reports of telegraph systems in the US and UK being affected, including a switchboard fire in Chicago. Variations in magnetic readings were observed at the Royal Observatory in Greenwich, UK. Later reports stated the storm lasted 15 days, coinciding with the observation of a group of sunspots.

The aurora borealis is caused by space weather

October 1903

This was the most significant solar storm during a solar minimum period on record, with effects showing that solar storms are a threat even when solar activity is weak/quiet. It caused widespread disruption to communications; huge spikes were recorded in voltages in telephone lines in Chicago and telegraph systems were affected in London.

May 1921

An intense geomagnetic storm across three days caused extensive aurora across North America. Labelled the New York Railroad Storm, it sparked a number of fires across the world and severely affected telegraph services in North America and Europe, damaging equipment, including undersea cables. It was estimated by some experts as on a par with the Carrington event.

January 1938

A massive solar storm took place across 10 days, causing aurora widely seen across North and Central America, the Caribbean and Europe. The low altitude red glow from the aurora led many people to mistakenly report fires. Interruptions to transatlantic and North American radio communications were recorded and some railway signalling equipment in the UK became inoperable.

August 1972

A storm caused widespread disturbances to electrical and communications grids throughout North America, disrupted satellites and caused accidental detonation of US naval mines near North Vietnam. The coronal cloud’s transit time to the Earth was the fastest ever recorded, at just 14.6 hours.

It has been calculated that an astronaut undertaking an extra-vehicular activity at the time could have received a near-fatal radiation dose, but thankfully this storm occurred between the Apollo 16 and 17 missions. Energetic solar radiation is one of the severest risk factors facing any future spaceflight beyond low Earth orbit.

Space Shuttle launch
In March 1989 a geomagnetic storm affected sensors on a fuel tank on the Space Shuttle Discovery. Energetic solar radiation is one of the severest risk factors facing any future spaceflight beyond low Earth orbit.

March 1989

A geomagnetic storm caused communications blackouts, a major power outage in Quebec, Canada, and the loss of positional knowledge for over 1,000 space objects for nearly a week. It also temporarily affected sensors on a fuel tank on the Space Shuttle Discovery. Another major storm in August 1989 – a year that saw significant solar activity – caused trading at the Toronto Stock Exchange to halt.

October 1989

This radiation storm was a series of large events occurring within one week. During the storm, astronauts on the International Space Station had to shelter in the furthest interior to shield themselves, but still reported seeing flashes with their eyes closed. By one measure it was the largest event in the space age.

July 2000

The Bastille Day Flare occurred on July 14, the national day of France. It was large enough to be observed by Voyager 1 and Voyager 2 far away in space. The solar flare was followed by a full-halo coronal mass ejection and a geomagnetic superstorm that caused damage to power transformers and satellites.

Halloween 2003

A series of storms around the end of October caused problems for deep space and near-Earth space missions. On Earth, they resulted in operators having to reroute aircraft and caused a power outage in Sweden. During the height of the solar activity, about 10% of the active operational satellite fleet – almost 50 satellites – reported anomalies, including one total loss and 10 cases of loss of operational service for more than a day. GPS systems were seriously affected including those used for surveying, deep-sea and land drilling, and some airline flights.

Large solar flare seen on 13 December 2006. Image copyright ESA/NASA
Large solar flare seen on 13 December 2006. A shower of high-energy particles appeared as specks and white streaks on the imagers aboard SOHO, the primary watchdog for solar storms. © ESA/NASA

December 2006

A major flare disrupted satellite-to-ground communication and GPS signals for around 10 minutes and damaged the solar X-ray imager on the satellite that took its image. The solar flare was unusual because the initial burst of particles to arrive were hydrogen atoms, rather than the expected ‘broken atoms’ such as protons and electrons, which arrived 30 minutes after the initial burst.

July 2012 – The one that missed Earth!

An extreme solar storm tore through Earth’s orbit… but missed us by a week, instead hitting the STEREO-A spacecraft. Experts believe it was as powerful as the Carrington event and twice as powerful as the 1989 event that caused the Quebec blackout, and could have caused mass disruption to satellite GPS and communication systems and widespread power blackouts. If it had hit Earth, it is estimated that the economic impact would have been around US$2 trillion and that it would have taken us years to recover.


Find out more

Space weather is one of the aspects studied by Space Situational Awareness (SSA) programmes, along with near-Earth objects and space debris. Find out more about SSA from industry experts in our RHEA Talk webinar on 5 October 2021.

Main image: The European Space Agency’s Solar Orbiter mission was launched in February 2020. © ESA/AOES