10 Notable Aspects of Solar Flares


To the unsuspecting person on Earth, the sun seems as permanent and unchanging as the land beneath our feet. It provides the light and warmth that makes life on this planet possible so steadily. It’s even been said that every hour, enough energy from the sun reaches the Earth to provide electrical power to all of humanity for one year.

And yet as a burning ball of gas with a radius 109 times that of planet Earth, the sun has numerous explosions on it of awe-inspiring size and power. While this has produced dazzling images, it’s not at all a safe spectacle. Indeed, as we’ll see in a moment, solar flares in the next few decades could be a horrible threat to civilization.

10. Their Immense Composition & Power

A solar flare is often accompanied by the release of a vast amount of gas, plasma, and irradiated particles called a coronal mass ejection. NASA has reported that the energy released in them would be the equivalent of a billion megatons of TNT (meanwhile, the largest nuclear explosion ever created by humans had the equivalent of 50 megatons). Despite being mostly gas, they are estimated to have millions of tons in mass as well.

A single instance that erupted from the sun in 1999 was estimated at being roughly 35 times the diameter of planet Earth. To be clear, that was by no means the largest recorded solar flare; that one came two years later. It possessed enough power that the Earth, 93 million miles away, had the number of electron-charged particles in its magnetosphere increased to ten thousand times its usual level.  

9. Mistaken for a Miracle

In June 2012 there was a report from a team of researchers in Japan that studying the rings of ancient cedar trees on the islands had revealed a there was a spike in carbon-14 that could not be accounted for. It befell a Yale student named Jonathan Allen to find an account from Anglo-Saxon historical records of how, in 774 AD, one night an immense red crucifix appeared in the sunset sky, an event which was accompanied by sightings of “wondrous serpents” according to the 1847 book A Catholic History of England.

While at the time, surely no one thought of the red light in the sky in such terms as “coronal mass ejection,” we now know that the supposed divine vision was very likely exactly that. There was a competing theory that the red crucifix was actually a supernova, although given how relatively small those are in the night’s sky, it would have been a very unusual supernova indeed to have even a poorly-defined crucifix shape.

8. The Year of the Discovery (Sort of)

It might seem odd, considering that seemingly esoteric aspects of the solar systems such as four of the moons of Jupiter were discovered by Galileo as early as 1610, but the nature of solar flares was completely unknown until September 1, 1859. The circumstances of its discovery were quite modest until they became spectacular. Cambridge graduate/amateur astronomer Richard Carrington happened to notice black spots on the sun, then saw two massive patches of white light erupting from the black spots, which he considered worth a sketch during the five minutes they were visible. By the nighttime, the event he just witnessed would make its effect felt around the world.   

The skies glowed so bright on September 2 that in some areas teams of workers went out under the assumption their day had begun. Elsewhere, the skies glowed such a bright red that reports of fires went around. As it happened, there were real fires. They happened to be at telegraph offices where the surge of electrical power from the Carrington flares would cause paper to burst into flame. At the American Telegraph Company in Boston, telegraph workers went through a process of finding their machines didn’t work, and then that they could get them to work without switching them on due to background energy. Then, by 10 a.m., their machines were working normally again. All told, Earth was hit with more than twice as much energy from the sun as it would be from any other recorded solar storm.

Even though the event came to be named after him, Carrington was rather unassuming about his findings. When he shared them, he didn’t make the connection himself between the coincidence of the solar display he’d witnessed and the bizarre auroras. He wasn’t even the only one to see the flares on the day, sharing that honor with astronomer Richard Hodgson, who also submitted a report on it. That’s posterity for you.

7. The Cold War Flare Scare

While the Carrington Event was naturally a wonder for its time, it didn’t really fully institutionalize the concept of “space weather.” That had to wait a little over a century. Until May 1967, to be more specific. Humanity almost coming to an end has a way of shifting priorities like that.

Although in those days, to the average person a series of solar flares didn’t really mean anything aside from some pretty auroras, documents that were declassified 50 years later revealed that the United States military was experiencing severe radar failures as a result of the largest bombardment electromagnetic energy that would hit Earth during the 20th Century. Their first reaction was to point the finger at the Soviet Union jamming their radar. Fortunately, a program that had been started by the Air Force only a handful of years before identified the real culprit. The notion that this would have led to nuclear war might seem far-fetched, consider that the Soviet Union nearly launched a nuclear attack on the US in 1983 as a result of satellite interference from high-altitude clouds (and was only dissuaded from it by the heroic disobedience of Stanislav Petrov).   

6. The Halloween Storms

While the US armed forces were able to keep the danger of the 1967 solar flares under wraps, that simply wouldn’t have been possible for this 2003 incident, which was the most severe solar event of the 21st Century. Despite the name that implies the effects of the solar activity only altered the Earth’s magnetosphere for a day, the world was actually subjected to massively increased electromagnetic energy from October 19 to November 7 from 17 solar storms.

The impact included the rerouting of numerous flights that normally had to fly near the North Pole, and knocking out the electrical grid in Sweden for an hour. The Eastern Seaboard for the United States also nearly suffered an outage. Geophysical surveys and even maritime missions were canceled. The year-old Japanese satellite ADEOS-II was left completely out of commission, and even terrestrial radio networks were disrupted. The fact that auroras were seen in the skies of Florida and Texas, locations which are usually much too far south for such sights, doesn’t really seem like much of a consolation.

5. The 2012 Flare that Nearly Ruined Us

The harm caused by the Carrington Event and the Halloween Storms may seem minor for disruptions that became global events. However, by July 29, 2012 the world became much more dependent on a telecommunications network, leaving it much more vulnerable when a total of three massive flares (two within 10 minutes of each other), the largest recorded solar event since 1859, threatened to hit the Earth again.

Luckily, the circumference of the Earth’s orbit around the sun is 584 million miles, and even with an object about 25,000 miles in circumference that leaves a lot of room for misses. Still, these three potentially disastrous flares were only a week’s time from hitting the Earth, a near miss in astronomical terms. It’s understandable, then, that as in 1967, NASA didn’t make knowledge of the near miss public… though for only a relatively modest two years this time around.  

4. The Threat to Astronauts

By this point, you might be wondering what would happen if, say, a shuttle of astronauts were caught outside the magnetosphere by the blast from a solar flare. Would they survive? Would they be debilitatingly irradiated? Well, in the case of the International Space Station, even a vehicle that’s left in an orbit 254 miles above the Earth has “storm shelters” on it. The Halloween Storms in particular compelled the personnel aboard to scramble for shelter. In there, fortunately, they were exposed to no more radiation than they’d have been in a trip through an x-ray.

Suppose, though, an astronaut had been caught out in the open in their spacesuit on the moon during a solar flare, as nearly happened during the Apollo 16 mission in 1972. According to NASA’s own reporting, they would have been subjected to roughly 50 times as much radiation as an x-ray, which certainly would have induced radiation sickness but wouldn’t have been fatal. However, in 1989 when astronauts on the space shuttle Atlantis were caught in a solar flare, analysis published in Storms from the Sun put forward that there was a 10% chance they would have died if they hadn’t been in a shelter.

It should be noted that, even in relative safety, a solar flare can still be a harrowing experience for an astronaut. In the case of the Atlantis the astronauts reported that they could still see flashes of light from their retinas burning. No matter how much the data might state that the radiation levels were not dangerous, that would be deeply convincing that something had gone deeply wrong with your body.  

3. Solar Flares Set the Stage for Life on Earth

We’ve mostly talked about how harmful solar flares can be for humanity, and for the next entry we’re really going to crank that up. But for this entry let’s give solar flares some credit, for a change. Much as they might threaten the future of humanity, they are a significant part of a reason it exists in the first place. In fact, that holds true for all life on Earth.

Billions of years ago, the atmosphere of the planet was composed almost exclusively of nitrogen molecules and carbon dioxide. It was the intense energy of coronal mass ejections that caused the nitrogen molecules to split oxygen molecules from the carbon dioxide. It didn’t just provide the gas we breathe, it also caused the creation of large amounts of nitrous oxide that would become the greenhouse gases at the top of our atmosphere. Theoretically, on top of all that, bombarding the loose chemicals on the ground allowed for the combinations that resulted in the first DNA and RNA.  

2. Real Chance of Solar Flare Disaster in Next Couple Decades

There are roughly 1,100 active satellites orbiting the Earth. Each of them has cost at least $10 million to install, and some have cost as much as $400 million. Imagine the financial damage it could do if they were all rendered defective by a massive coronal mass eruption, just in replacing them. Imagine the revenue lost from the downtime while waiting for repairs or replacements. The information and files that could be lost from the cloud forever. That’s not even considering the damage that could be done to the energy grids for any number of nations, for who knows how long. Considering all that, when the National Academy of Sciences put the cost of recovering from it at potentially two trillion dollars, it’s not hard to believe them.  

What are the odds this will happen? In February 2012, Predictive Science senior member Pete Riley published in Space Weather that the chance of the Earth being hit by one of the numerous solar flares was roughly 10% in the next few years — the reason being that the sun is currently undergoing an 11-year cycle whereby it expands and contracts, and it’s currently undergoing a more intense period. Not that we’d be completely safe if it doesn’t happen during the intense periods. The aforementioned Halloween Storms, for example, were a bit of a fluke that happened during a period of less solar activity.

1. Countermeasures?

So how do we protect our current electric grids and communication networks from the coronal mass eruptions? The equipment is there, but frankly, it seems hard to imagine us even trying. To give an idea of the amount of resources that it would require, the Foundation for Resilient Societies estimated that just buying enough equipment to retrofit all the transformers that would protect electric grids in the event of a Carrington Event-level disaster would cost as much as $30 billion.

The same foundation testified before congress in 2016 that the US updating its energy grid would require roughly 5% of the US’s annual defense budget, or well over $35 billion a year just to update the infrastructure, and that’s without regard for telecommunications. While a 10% chance of an economically ruinous natural disaster is certainly higher than we’d like, it hardly means we’re doomed. So essentially, you’d be looking at selling the world’s leaders and population on making such a costly sacrifice for a potential disaster, without firsthand experience with one.

Dustin Koski is the author of the urban cult fantasy novel Not Meant to Know.

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