In 774 AD, an extremely powerful explosion of matter and energy from space hit the Earth.
Nothing like this has been felt on this planet for 10,000 years. A mixture of high-energy light and highly accelerated subatomic particles, when this wave hit the Earth, changed our atmospheric chemistry enough to be measured centuries later.
Our pre-electronics companies have been completely unaffected by this. But if this type of event were to happen today, the results would be bad.
It was first discovered through an analysis of tree rings, of all things. The scientists found that the level of carbon-14, a carbon isotope, was much higher in the rings that year than usual. A few years later, examining the air samples in the ice cores, the scientists saw that there were also high levels of beryllium-10 and chlorine-36.
The common factor in all these elements is that they are created when subatomic particles with extremely high energy hit the air and soil of the Earth. They collapse into the nuclei of atoms and change them, creating these isotopes. The only way to get particles at such energies is from space, where strong magnetic fields in exploding stars, for example, can accelerate particles at such high speeds. We call these isotopes cosmogen, made from space.
What could have created the space storm in 774 AD? The obvious candidate for such a thing is a very strong solar flare, an explosion on the Sun created when intense magnetic field lines become tangled and short-circuited, releasing huge explosions of energy and particles. But the event of 774 was so strong that at first scientists were skeptical, possibly due to an eruption. Once any other type of astronomical phenomenon was ruled out, however, a rocket remained.
A team of scientists went through the evidence to analyze other such events in the hope of classifying this eruption compared to other known eruptions. What they found is that this event was much more powerful than even some relatively scary modern missiles.
For example, in 1989, the Sun erupted in a powerful series of flames, as well as in a huge coronal mass ejection (or CME), where billions of tons of hydrogen plasma are discharged at high speed. Carrying its own magnetic field, this crisis of space time it hit the Earth’s magnetic field, affecting it so deeply that electric currents were induced beneath the Earth’s surface. Called geomagnetically induced currents, this additional electricity blew up transformers in Quebec and caused a power outage that lasted for hours.
February 1956 was the strongest solar storm in the modern era, which was slightly twice as strong as the 1989 event. Our electricity grid was not as intensely used at the time, so it did not cause the same damage like the 1989 event, but it was still a huge event.
Using various methods to characterize the 1956 storm, including measurements in visible light, radio waves, changes in the Earth’s ionosphere (a layer of high-altitude ionized air that, when rapidly changing, can affect ground magnetometers that measure field strength magnetic) and, moreover, discovered that the event of 774 AD. it was amazing 30 to 70 times stronger. That means it probably was 100 times stronger than in 1989.
It is not clear how long the rocket lasted; the strongest grow and decompose in a few hours. But the total energy released in this flame was about the same as that which the whole Sun radiates in a second: 2 x 1026 Jouli, or the equivalent of about 100 billion megaton bombs that disappear.
It’s a lot of energy. Enough to power our entire planet (given our current use of energy) for 300,000 years.
Yegads.
A rocket like this is called a superflare, and until now it was not believed that the Sun can produce them (other stars that are more magnetically active make them quite often). Scientists believe that the 774 flame could have been a special circumstance, in which a strong flame occurred near a gas whistle called a filament, knocking it down and accelerating its protons to such high energies.
This is actually a relief! I’d rather it’s hard for the Sun to do that.
Such an event that happens today would be catastrophic. It could eliminate many satellites – high-energy particles and radiation can shorten even hardened electronic components – and cause widespread disruptions. These could take a long time to fix, as the larger transformers used by electrical networks cannot be mass-produced. Some scientists have calculated that passengers on international flights could receive a lifetime dose of radiation within hours of such an event.
The effects on the Earth can be difficult to determine; in part, it depends on whether the flare and the magnetic polarity of the CME (north-south side of the magnetic field) are able to couple with the Earth’s magnetic polarity. Otherwise, we will receive feathers and other damages. But some of the effects appear in both directions.
I will note that I have not seen such a strong event since 774, although many were quite strong. The sun erupted in 2012 in a coronal mass ejection that, if it had hit the Earth, would have been worse than the 1989 event. Fortunately, it was sent in another direction.
But it is clear that the Sun can be quite angry and we need to take this seriously. Certainly, solar astronomers do, and as the Sun rises in its newest magnetic cycle, it looks at our star with all that they have. We do not know how strong this cycle will be; one prediction is that it won’t be a big deal, but another says it will be a lot.
We will see. Clearly, we need to learn a lot more about the Sun. It is no exaggeration to say that our modern life depends on it.