On September 1, 1859, amateur astronomer Richard Carrington made a discovery that would forever change the world. When the 33-year-old pointed his brass telescope towards the sky, he noticed a bright light suddenly appear above a grouping of large sunspots. At first, he thought it was a malfunction of his equipment, but he would soon realize he was watching an event blasting from the Sun itself.
We now know that what Carrington observed was the largest geomagnetic storm on record to hit Earth. In the days that followed, the “Carrington Event” spewed electrified gas and subatomic particles amounting to the energy of 10 billion atomic bombs towards the planet, causing telegraph communications to fail, literally shocking operators, and causing systems to catch fire. Northern Lights were reported as far south as Cuba and Hawaii, allowing witnesses to read newspapers by the light of the auroras alone.
Bear in mind, this all occurred in the same year that the first successful gasoline engine was demonstrated. In an era where modern technology rules our every move, a similar solar event would have detrimental effects that would impact nearly every aspect of life, from your ability to post a selfie to how your toilet flushes. But to understand how such an event would impact our world today, we first need to grasp how space weather works.
The Three Stages Of A Solar Storm
The Sun’s power comes from nuclear fusion, turning hydrogen into helium and liberating energy in the form of light and heat. The hydrogen is in a charged plasma form, and as it moves it creates powerful currents and magnetic fields.
During the first stage of a solar storm, this magnetic energy can be released in spectacular fashion and is accompanied by X-ray and ultraviolet (UV) emissions. These are called solar flares. If these events are associated with the release of high-energy particles, they can become fully fledged solar storms or coronal mass ejections (CMEs), which we can think of as Sun “burps” (if the Sun belched with the power of 20 million nuclear bombs). During a CME, heated gas bubbles called plasma eject from the Sun, sending shockwaves rippling through the Solar System. Astronomers don’t know exactly why these occur but agree that the Sun’s magnetic field has something to do with it. The Sun is not a solid but made of plasma, a fluid-like state of matter that's electrically charged. This state is subjected to turbulence, and turbulence moves the Sun's magnetic field lines in much the same way as when we stretch a rubber band. Stretch it too much, though, and it will snap.
Altogether, the three combine to create the perfect solar storm.