On 13 October 2016, President Barack Obama issued an executive order aimed at preparing the nation’s infrastructure for “extreme space weather events” that could potentially be powerful enough to wreak havoc on essential electrical grids:

Space weather has the potential to simultaneously affect and disrupt health and safety across entire continents. Successfully preparing for space weather events is an all-of-nation endeavor that requires partnerships across governments, emergency managers, academia, the media, the insurance industry, non-profits, and the private sector.

Astrophysicist Valerie Rapson, an outreach astronomer at the Dudley Observatory at miSci in Schenectady, explained to Albany television station WNYT why a large solar storm could disrupt life on Earth. A solar flare is an eruption on the Sun’s surface, and while they are not uncommon, a large enough occurrence of flares could have a significant effect on daily life: “If we get a direct hit here on earth, it can cause our power grids to go down. It can damage our satellites,” Dr. Rapson said.

Dr. Rapson’s warning was echoed in the executive order, posted to the White House web site:

Space weather events, in the form of solar flares, solar energetic particles, and geomagnetic disturbances, occur regularly, some with measurable effects on critical infrastructure systems and technologies, such as the Global Positioning System (GPS), satellite operations and communication, aviation, and the electrical power grid. Extreme space weather events — those that could significantly degrade critical infrastructure — could disable large portions of the electrical power grid, resulting in cascading failures that would affect key services such as water supply, healthcare, and transportation.

The largest solar storm in known history happened in 1859 and is known as the Carrington Event, named for British astronomer Richard Carrington who recorded it. But now, life on Earth is far more dependent on electrical power, and most of the daily activities we take for granted rely on an operational electrical grid, Rapson said:

Our biggest danger is really kind of frying the satellites or sending a power surge through our power grids and knocking out power for a majority of the country or even the world.

Even in 1859, the Carrington Event caused visible effects. Scientists told National Geographic in 2011 that “people in the northeastern U.S. could read newspaper print just from the light of the aurora” caused by the event, while telegraph operators noticed sparks flying from their machines, enough in some cases to cause fires:

In 1859, such reports were mostly curiosities. But if something similar happened today, the world’s high-tech infrastructure could grind to a halt.

“What’s at stake,” the Space Weather Prediction Center’s [Tom] Bogdan said, “are the advanced technologies that underlie virtually every aspect of our lives.”