Are We Ready for Solar Storms?

In May 2024, a team of scientists from 30 U.S. government agencies received a worrying alert: The planet was under threat. An eruption from the sun was sending high-speed charged particles straight toward Earth. The team had just minutes to react before the blast set off a geomagnetic storm. This outburst of energy could cause widespread power outages, ground airplanes, and knock out radio, communication, and GPS satellites. Scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) who received the warning had to work together to minimize the effects of the incoming storm.

A geomagnetic storm is a disturbance of Earth’s upper atmosphere caused by high-energy particles and radiation from the sun. The increased solar activity disrupts the magnetic field that surrounds Earth. This invisible field is created by electrical currents moving in and around the planet.

Thankfully, the alert received that May wasn’t real. It was just a drill to practice how to handle this type of emergency. But as the group was dealing with the pretend disaster, they were interrupted—by a real-life geomagnetic storm! It was the most severe one to hit Earth in two decades. Suddenly, officials had to deal with the actual scenario they were training for. The experience revealed something important: We need to be better prepared for catastrophic space weather.

In May 2024, scientists from 30 U.S. government agencies received a worrying alert. The planet was under threat. An eruption was happening on the sun. High-speed charged particles were heading straight toward Earth. The team had just minutes to react. Soon the blast would set off a geomagnetic storm. This outburst of energy could cause widespread power outages and ground airplanes. It also could knock out radio, communication, and GPS satellites. Scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) got the warning. They had to work together to lessen the coming storm’s effects.

A geomagnetic storm is a disturbance of Earth’s upper atmosphere. It’s caused by high-energy particles and radiation from the sun. The increased solar activity affects Earth’s magnetic field. This invisible field surrounds Earth. It’s created by electrical currents moving in and around the planet.

Thankfully, the alert in May 2024 wasn’t real. It was just a drill to practice this type of emergency. But as the group handled the pretend disaster, a real-life geomagnetic storm interrupted them! It was the most severe one to hit Earth in two decades. Officials were training for this situation. Suddenly, they had to deal with the real thing. The experience revealed something important. We need to be better prepared for destructive space weather.

Charged particles constantly stream from the sun toward Earth as solar wind. Our planet’s magnetic field acts like a protective bubble, deflecting most of these particles. Periodically, increased activity on the sun causes solar flares, which are eruptions of light, heat, and energized particles. They’re often accompanied by another type of solar outburst called coronal mass ejections (CMEs). These massive, invisible clouds of superhot charged gases erupt from the sun’s surface. They can be millions of miles across and have their own magnetic fields.

If a CME hits Earth’s magnetic field, the collision can trigger a massive geomagnetic storm. About 170 years ago, British astronomer Richard Carrington became the first person to document this phenomenon. He observed that after a bright explosion on the sun, electrical devices, like telegraph message  machines, malfunctioned around the world.

Charged particles constantly stream from the sun toward Earth. They make up the solar wind. Our planet’s magnetic field acts like a protective bubble. It blocks most of these particles. At times, increased activity on the sun causes solar flares. These are eruptions of light, heat, and energized particles. They often come with another type of solar outburst called coronal mass ejections (CMEs). These are massive, invisible clouds of superhot charged gases. They erupt from the sun’s surface. CMEs can be millions of miles across and have their own magnetic fields.

If a CME hits Earth’s magnetic field, it can trigger a massive geomagnetic storm. About 170 years ago, British astronomer Richard Carrington was the first person to document this effect. He observed a bright explosion on the sun. Then electrical devices, like telegraph message machines, malfunctioned around the world.

Scientists generally know a CME is headed our way only a couple of days in advance. And they know if it will cause a geomagnetic storm only a few minutes to hours before it happens. “About a million miles from Earth we have several spacecraft that hang out in this place called Lagrange 1, where Earth’s pull of gravity equals the pull of the sun,” says Jim Spann. He’s a senior scientist at NOAA’s Office of Space Weather Observations who helped organize the drill. “The spacecraft make observations of the sun and see when a big cloud of electrified gas comes our way. It’s like a weather station in space.”

When a CME passes over Lagrange 1, scientists almost instantly receive data about its speed, its density, and the orientation of its magnetic field (like a magnet, its charges are aligned in one direction). This information can help determine how big of a threat the CME poses. If its magnetic field is aligned in the same direction as Earth’s, the cloud will largely be deflected (like when two north or south ends of a magnet repel one another). But if a CME’s magnetic field is oriented opposite to Earth’s, the two will attract and merge. “This dumps a lot of energy into the atmosphere, causing Earth’s magnetic field to stretch out like a rubber band,” says Spann. “And when it whips back down, a lot of energy is released back into the atmosphere.”

Scientists can tell if a CME is headed our way. But they usually know it’s coming only a couple of days in advance. Will it cause a geomagnetic storm? They know that only a few minutes to hours before it happens. Jim Spann is a senior scientist at NOAA’s Office of Space Weather Observations. He helped organize the drill. “About a million miles from Earth we have several spacecraft that hang out in this place called Lagrange 1, where Earth’s pull of gravity equals the pull of the sun,” he says. “The spacecraft make observations of the sun and see when a big cloud of electrified gas comes our way. It’s like a weather station in space.”

When a CME passes over Lagrange 1, scientists receive data almost instantly. They learn about its speed, density, and magnetic field. (The field’s charges all aim in one direction, like the field of an ordinary magnet.) This helps determine the size of the threat from the CME. If its magnetic field is aligned in the same direction as Earth’s, the cloud will be mostly repelled. (It’s like the way two north or south ends of a magnet repel one another.) But what if a CME’s magnetic field is aligned opposite to Earth’s? Then the two will attract and merge. “This dumps a lot of energy into the atmosphere, causing Earth’s magnetic field to stretch out like a rubber band,” says Spann. “And when it whips back down, a lot of energy is released back into the atmosphere.”

That energy burst can destroy satellite circuitry and the solar panels that power them, leaving people without cell phone service or other means of communication. It can also create an electrical current that overloads and damages power grids, leaving people in the dark without power for days.

Another effect of a geomagnetic storm is colorful auroras (see “Solar Storms”). The 2024 geomagnetic storm that disrupted the scientists’ drill produced auroras worldwide—even in areas that rarely experience them, like Hawaii and Florida. In the Midwest, farming equipment that uses GPS failed, forcing farmers to delay planting, causing billions of dollars in crop losses.

That energy burst can destroy satellite circuits and the solar panels that power them. People might be stuck without cell phone service or other means of communication. The burst can also create an electrical current that overloads and damages power grids. People could be in the dark without power for days.

Geomagnetic storms also cause colorful auroras (see “Solar Storms”). The 2024 geomagnetic storm during the scientists’ drill produced auroras worldwide. They were visible even from areas that rarely see them, like Hawaii and Florida. In the Midwest, farming equipment that uses GPS failed. Farmers had to delay planting. This caused billions of dollars in crop losses.

The scientists concluded that the drill and the real-life storm had demonstrated a critical need for better forecasting of space weather. But technology to predict a CME early enough for Earth to prepare for its impact simply doesn’t exist. At least, not yet.

Spann says NOAA, along with the European Space Agency, is working on a spacecraft called Vigil that could improve how we monitor space weather. Currently, a spacecraft observing solar activity at Lagrange 1 can detect a CME only if it’s rushing toward the craft head-on, explains Spann. Instead of sitting directly between Earth and the sun, Vigil will sit off to the side. That will give scientists a wider view, so they’ll have a better idea when a CME will strike our planet.

The scientists learned something from the drill and the real-life storm. We have a critical need for better space weather forecasting. Scientists can’t predict a CME early enough for Earth to prepare for its effects. The technology simply doesn’t exist. At least, not yet.

Spann says NOAA and the European Space Agency are working together on a spacecraft called Vigil. It could improve space weather tracking. Now spacecraft observe solar activity at Lagrange 1. They can detect a CME only if it rushes toward them head-on, explains Spann. But Vigil won’t sit directly between Earth and the sun. Instead, it will sit off to the side. That will give scientists a wider view. They’ll have a better idea when a CME will strike our planet.