In other episodes, we talked about solar storms: electromagnetic radiation that flows from the Sun to Earth. In severe cases, they can disrupt our electricity and communication systems.

One very severe event happened a hundred years ago, in 1921, and lasted for 3 days when a large group of sunspots emitted bursts of plasma called coronal mass ejections.

Traveling a million miles an hour, these can take 1 to 3 days to reach Earth. Once here, their energy can create electrical currents that flow along conductive rocks, often jumping to phone and power lines.

In this 1921 event, electricity spiked to 1000 volts along telegraph wires, causing stations to burst into flames and rendering this communication network useless.

Severe solar storms hit earth about once a century, so we’re due for another one. In a much more interconnected world, what could happen this time?

Satellites could be affected, meaning we may temporarily lose GPS and other communication.

Airline passengers might be exposed to increased radiation, and airplane control systems could be impacted.

Modern infrastructure, internet, and electric grids—far larger than a century ago—could be especially at risk.

There are dozens of solar storms each year, but most are not aimed at Earth, so their energy travels into space. Still, scientists monitor solar activity closely to detect solar storms before they may reach Earth, allowing us time to prepare our systems.