How does space weather affect us here on Earth?

Space weather brings us the shimmering auroras known as the Northern and Southern Lights. But its effects aren’t always so benign. In certain circumstances, it can wreak havoc on our technology-dependent civilization.

Partly cloudy with a chance of rain … in space?

No, this kind of weather is different. It isn’t forecasting if astronauts need umbrellas when they go out for a spacewalk. Space weather is all about disturbances in our near-space environment and on Earth caused by the Sun.

The Sun is more than just the source of visible light and life-sustaining heat on our planet. It’s also a fluctuating source of X-rays and a “wind” of high-energy charged particles that blows outward, carrying within it an embedded solar magnetic field. Interacting with Earth and its magnetic field, these emissions cause space weather.

The Sun may look calm and static from Earth but there is constant activity on its surface, like this solar eruption captured on April 21, 2015. Credit

You’ve got my attention…

Earth’s magnetic field normally protects us from space weather. But during a powerful solar storm, Earth’s magnetic field can buckle. This is most often seen when the storm is accompanied by a coronal mass ejection—a large expulsion of material (plasma) and accompanying magnetic field from the Sun—and the magnetic fields of the Earth and the Sun are aligned oppositely, allowing them to “connect.” A coronal mass ejection can expel up to 100 million tons of solar material from the Sun’s surface at speeds more than two million miles per hour.

How can space weather harm our technology—and us?

A powerful solar storm generates electric and magnetic anomalies that can have severe and widespread effects:

• Radio communications can be distorted or blacked out.
• Research, telecommunications, navigation, and weather satellites can suffer hardware failures and computer errors.
• It can generate ground electric currents that can overload transformers and cause massive damage to electrical grids.
• Astronauts as well as passengers and crew flying polar routes are vulnerable to higher than normal levels of radiation.

So government, industry, the commercial sector, and the public all have a stake in understanding and preparing for solar storms because they rely on technologies that space weather can disrupt.

This short video clip shows the Sun unleashing a medium-sized solar flare with a stunning coronal mass ejection. Credit

Have there been any big space weather events in the past?

Some. The biggest solar storm was the Carrington Event of 1859, named after a British astronomer. That solar outburst, which occurred at a time long before society became reliant on technological systems vulnerable to space weather, still caused a storm that electrified telegraph lines, shocking technicians and setting their papers on fire. The Northern Lights, usually only visible in the far north, could be seen in Central America, the Caribbean, and Hawaii.

There have been other events since then. For example, in 1989, northeastern Canada’s Hydro-Québec power grid collapsed within 90 seconds of a big solar storm. Millions of people were left without electricity for 9 hours afterward.

The aurora borealis (aka the Northern Lights) is the most visible effect of the Sun’s activity on Earth’s atmosphere. Credit

Can we forecast solar storms?

Predicting space weather is challenging. Many complex systems are involved—the Sun, solar wind, Earth’s magnetic field, and Earth’s atmosphere. Then the interaction of these systems heightens the complexity. In the United States the forecasting task falls primarily to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC) and the U.S. Air Force’s Weather Agency. NASA helps, too. The SWPC uses space- and ground-based data sources, such as satellites and telescopes, for its work providing forecasts, watches, warnings, and alerts to anyone affected by space weather.

SWPC forecasters analyze the near-real-time data they gather to assess the current state of the environment from the Sun to the Earth. They also analyze the approximate 27-day recurrent pattern of sunspots, an indicator of solar activity. They carefully look at current conditions and compare them to the past, combining that information with the output of numerical models similar to weather models. Based on the analysis of all of this information, forecasters can predict space weather from the coming hours to the coming weeks.

In recent years, people have increasingly recognized the importance of research into the causes and consequences of solar storms. A growing community has come to depend on constant and immediate access to space weather information.

Protecting the electrical power grid is one of the most important current priorities for experts preparing for a solar superstorm. Credit

How can we prepare for and protect ourselves from space weather?

Steps to prepare for, and mitigate, the hazards of space weather include identifying and replacing susceptible equipment, developing self-checking and self-correcting devices, and establishing protocols to cope with equipment failure. Though a solar superstorm could still cause massive disruption, greater recognition of the problem and better preparations could reduce our vulnerability to these threats. Perhaps the most important current priority is protection of the electrical power grid, which has a number of known vulnerabilities, especially to its large, expensive, and special-order transformers.

Is there real cause to worry about the potential havoc of space weather?

Minor solar storms are relatively common. But once every century or so, the Sun unleashes a major storm. Most of these superstorms miss Earth and stream harmlessly into space. But if an especially large storm were to hit Earth, the damage in the United States alone to electrical grids, satellites, aviation, and other parts of our infrastructure could run into the hundreds of billions of dollars.

A solar superstorm is an excellent example of a low-probability/high-consequence event, similar to earthquakes, tsunamis, volcanic eruptions, terrorist attacks, or major wars. Such events can have a huge impact on society, but they don’t occur often enough to force people to plan for them.

Where do we go from here?

Preparing for a solar superstorm, like preparing for other low-probability/high-consequence events, requires time, leadership, and resources. Policy makers need to keep the public focused on what could happen and institute policies that will lessen the rare event’s effects. Appropriate technologies can minimize disruptions, but organizations need to be prepared, too. And research is critical: the more that’s known about the possibility and consequences of a solar superstorm, the better prepared society can be.

Take a Deep Dive

Ready to learn more? You’ll find lots more information in Solar and Space Physics: A Science for a Technological Society.

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