Biggest Geomagnetic Storm Hit Earth 150 Years Ago: What Have We Learned? And Are We Ready for the Next One?

On one faithful September night in 1859, two British astronomers- Richard Carrington and Richard Hodgson, peered at the Sun via telescopes and witnessed a remarkable phenomenon. A massive ejection spewed from the Sun. Within a couple of days, others on Earth noticed streets of colorful aurora across the skies and telegraph lines erupting in sparks.

Named after the astronomer that was first to describe the event, the solar flare is dubbed the Carrington Event. Despite occurring roughly 150 years ago, it stands as the strongest known geomagnetic storm to date.

What Humans have Learned from Geomagnetic Storms?

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When electromagnetic radiation erupts from the surface of the Sun, solar flares occur. These bursts only last a few minutes, although there are rare occurrences that they last significantly longer. Often associated with coronal mass ejections that blow out gas material and magnetic fields to space. However, not all solar flares or CMEs will have an impact on our planet. It depends on the size and direction of the burst. If a solar flare does occur on the Sun's far side, it will unlikely affect the Earth, reports DiscoverMagazine.

If a solar flare does occur on the near side, the burst's direction often misses Earth since it's relatively far and small compared to the Sun. For example, in 2001, NASA reports one of the biggest solar flares in the planet's history exploded CME at a speed of roughly 4.5 million miles per hour; luckily, it swept past Earth and onward to space.

In addition, during the Carrington Event, human technology was fairly simple, although the event had a significant impact on telegraph lines. At that time, people were forced to unplug wirings to stop sparks from erupting. However, these devices remained partly functional because of the particles ejected from solar flares that struck the current lines causing a partial disruption of technology. Although, some experts want more storms because it is a natural way of getting rid of space debris, explains Halford.

In earlier events, researchers recently discovered that solar flares impacted life on Earth in 993 AD and left evidence on tree trunks uncovered by archaeologists and are used today to date ancient wood material such as the brief Viking settlements in the Americas. During World War I, geomagnetic storms confused detection equipment. Technicians at the time mistook the interference as bomb-dropping but were only the flare hitting the planet's magnetosphere, explains Alexa Halford, an associate chief at NASA's Goddard Space Flight Center.

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Developments and Future of Solar Flares

The events of 1989 were eye-opening for infrastructure planners. Power companies started to build safety measures like tripwires into the electric grid to stop the cascading failure should solar flares impact Earth again. If power increases too quickly, the installed tripwires are programmed to switch off so that damages would be limited, and transformers won't burn out as they did during the Carrington Event.

Humans have spent decades learning new ways of lessening the negative effects of solar flares and CMEs on our quality of life. Various fields have dedicated resources to ensure that solar flares and CMEs pose almost no threat to how life functions on Earth. Luckily so, a study published in 2019 in the journal Scientific Reports, titled "Probability estimation of a Carrington-like geomagnetic storm," found that the statistical chances of another Carrington-like event occurring before 2029 are only 1.9% or less.