It is one of the main factors for the development of life on Earth; however, under the right conditions it could wipe out all our progress in a matter of minutes. At first glance, the Sun seems stable and reliable, but once it starts firing plasma and radiation, alarms go off. If a coronal mass ejection far more intense than normal were to strike the planet, the resulting geomagnetic storm could throw into chaos everything that depends on electricity to function. The worst part? This has already happened before.
If we look for a similar case in the broad spectrum of science fiction, one of the first choices would be "The Day the Earth Stood Still". In the original version, Klaatu's demonstration is forceful: the entire world, without electricity for thirty minutes, with the only exceptions being hospitals and airplanes in mid-flight. Now, imagine the planet 'frozen' in that way for a longer time... and without filter.
The most striking thing is that we don't need any alien for that. Our own Sun could trigger a similar event, and if we study its history, it wouldn't be the first time. In one of its latest videos, the folks at Kurzgesagt explore the power of solar storms and their consequences if they hit Earth with an intensity far above normal. The question is: how does something like that start, when the Sun seems so calm...?
Note: Spanish subtitles are now available.
Coronal Mass Ejections and Solar Storms
The Sun is like a giant ocean of plasma, which is altered by its own magnetic field. A magnetic field creates electricity, and electricity creates a magnetic field, which leads us to the solar dynamo, a fundamental process for the Sun to maintain its magnetic integrity. The energy of the field spreads throughout the Solar System carrying plasma, what we usually call solar wind. But changes in the plasma flow also cause changes in the magnetic field, creating 'knots' with a gigantic amount of accumulated energy. When those knots break, the Sun throws everything... and in all directions.
A solar flare (or sun eruption, if you prefer) sweeps away the solar wind particles and accelerates them to speeds very close to that of light. On the other hand, a coronal mass ejection can shoot millions of tons of plasma from the solar atmosphere, developing a respectable nine million kilometers per hour. But the Earth has very good defenses, and these changes in the 'solar weather' don't affect humanity... in the vast majority of cases. In fact, sometimes we get to enjoy their 'impact' in the form of auroras.
https://old.neoteo.com/survivor-library-una-libreria-contra-el-apocalipsis/Geomagnetic Storms and the Carrington Event
However, the concept of a 'solar superstorm' is perfectly valid, and we know that there are one or two of those per century. If an ejection has the minimum necessary size and its magnetic field is aligned with Earth's, conditions arise for a geomagnetic storm. Once again, humans won't feel anything, but their electricity-based creations could have a very rough time.
Without a doubt, the most remembered case is the Carrington Event. Collapse of the telegraph network, electric shocks to its operators, auroras all over the world. Despite the limits of our technological development, the event left its mark. In 2012, a solar storm of similar magnitude to the Carrington Event missed Earth by just nine days. It is estimated that the cost to repair damages after a storm with these characteristics would be around 2.8 trillion dollars only in the United States, twenty times the cost of Hurricane Katrina. The good news is that we can defend ourselves against something like this, but preparation is key.
