C H A P T E R
N ° 2’¹
Historical Space Weather Events
As the world increasingly gets more dependent on technology - especially within critical national and global infrastructures - it increases societies vulnerability to space weather impact. It is due to this concern that the focus on space weather awareness, research and the search for mitigation measures has increased.
Space weather is caused by solar activities and - when Earth-directed - they can cause a noticeable impact on our critical infrastructures. When a space weather event occurs, it increases the radiation level in the space environment surrounding Earth and – if strong enough – it can interact with Earth’s magnetic field and the upper layer of the atmosphere (i.e. the exosphere).
In a worst-case scenario, the intensity level of the radiation will get so high, that it penetrates through the Earth’s atmosphere and interacts with ground-levels. However, it is important to note that space weather is not dangerous to the human body at ground-levels.
Image Credit: ESA
As space weather is a fairly new recognized discipline, recorded space weather impact is quite sparse. However, there are three historical events which stories get repeatedly referred to within the space weather community. In today’s article - marking the first part of this three-part mini-series (trilogy) - we will look into the most feared event of them all: The Carrington Event. All this, to hopefully illustrate the importance of space weather awareness and the implementation of mitigations measures.
The Carrington Event (1859)
The Carrington Event, named after the British astronomer Richard C. Carrington, took place in 1859 from August 28’th to September 07’th. One night in August in Florida, the dark sky suddenly lit up with vibrant colors. The sky was so bright that people started waking up thinking that the nearby swamp had caught fire. Yet, what they had witnessed was, in fact, the Aurora Borealis (i.e. Northern Lights).
A few days later – on September the 1’st – Richard C. Carrington went out to study a group of sunspots using dark filters to protect his eyes when he suddenly saw an intense flash of white light from the area of the sunspots. 17 hours later, the dark sky from North America to Panama in south located in Central America lit up as if it was daytime. It was an even brighter Aurora than that witnessed in Florida in August. People woke up thinking it was morning and started reading their newspapers in the light. Gold miners in the Rocky Mountains woke up and made coffee and breakfast at 1.00 AM thinking the Sun had risen on a cloudy morning.
Image Credit: Serey Kim: Aurora.
Image Credit: NASA: Sunspots shown on the Sun as dark regions.
The event did not only cause Aurora in the U.S. but also at the South and North Pole and the equator from Canada to Australia. The needles of instruments measuring changes in the Earth’s magnetic field started to pin off-scale and the worlds telegraph system – which was one of the most advanced technologies at the time – collapsed leaving people incapable of sending messages. In some cases, the telegraph equipment even caught fire due to the intense increasement of currents and it also caused electrical disruption from Paris to Boston.
In 1859, scientists could not understand what had caused such intense Aurora and the consequential affects. Yet with time, they started to understand that it was caused by events happening on the Sun. Today we know, that what parts of the world experienced in 1859 was a geomagnetic storm classified as ‘extreme’ within the U.S. National Oceanic and Atmospheric Administration (NOAA) Space Weather Scales and Benchmarks and which was caused by a Coronal Mass Ejection. This storm is now known to be the most intense geomagnetic storm recorded in space weather history.
The Carrington Event happened during a time where not much technology was invented or implemented into society. Yet, it still had a profound impact. It is difficult to predict with how far intervals an event of the size of that of the Carrington Event could take place. Although, a suggestion from scientists working at NOAA is approximately every 500 years. However, half the size of this type of event is estimated to happen around every 50 years which is a lot more frequent.
In today’s society, we do not rely on telegraph networks to communicate. However, we are highly dependent on our satellites for communication and for the functioning of other vital services and these are still vulnerable to space weather. Thus, a storm like the Carrington Event would still cause a significant impact on our technology today, consequently leading to noticeable impact on our national and global critical infrastructures.
In 2023 it was, for example, estimated through sources used by the Council of the European Union General Secretariat that 20-40 million people in the U.S. alone could end up with no electricity for a period of 16-days to 1-2 years due to the impact from a space weather phenomenon at the size of the one creating the Carrington Event. Likewise, studies looking at the UK estimated that it could take weeks to months to repair the potential damage caused on the UK’s power grid system by such an event. Worldwide the financial loss is estimated to be between 7-42 billion US dollars per day.
Image credit: NASA/STEREO: The July 2012 solar storm - photographed by STEREO - was a Coronal Mass Ejection of comparable strength to that of the 1859 Carrington Event.
Sources
UK Severe Space Weather Preparedness Strategy (2021): https://assets.publishing.service.gov.uk/media/614dea50e90e077a368ffc48/uk-severe-space-weather-preparedness-strategy.pdf
DK Nationalt Risikobillede 2022 (2022): https://www.brs.dk/da/nyheder-og-publikationer/publikationer2/alle-publikationer/2022/nationalt-risikobillede-2022/
Council of the European Union General Secretariat (2023): https://www.consilium.europa.eu/media/68182/solar-storms_a-new-challenge-on-the-horizon-21-nov-2023_web.pdf
NOAA (n.d.) https://scijinks.gov/what-was-the-carrington-event/
N. Buzulukova and B. Tsurutani (2022): Space Weather: From solar origins to risks and hazards evolving in time. Front. Astron. Space Sci., Vol. 9. DOI: https://doi.org/10.3389/fspas.2022.1017103
