How Does Space Weather Affect Earth?

Space weather is a term used to describe the conditions found in the region of space surrounding the Earth and beyond that can affect our planet in a number of ways.

The sun is the main source of space weather, which can manifest itself in a variety of different phenomena, including solar flares, coronal mass ejections and geomagnetic storms, among many others.

While the Earth's magnetic field, or magnetosphere, largely protects us from charged particles emitted by the sun, space weather phenomena can sometimes have an impact on our planet, interfering with life and technological infrastructure, both in space and on the ground.

Space weather originating from the sun
Stock image: An artist's illustration showing how particles and magnetic field ejected by the sun interact with the Earth's magnetosphere. iStock

What is a Geomagnetic Storm?

The sun is constantly spewing out streams of energized, charged particles, or plasma, at high speed—known as the solar wind—that can have an impact on the Earth.

Variations in the solar wind, such as when it accelerates to particularly high speeds, can cause temporary changes in our planet's magnetic field and ionosphere—the part of the Earth's upper atmosphere beginning at around 50 miles above sea level—triggering geomagnetic storms.

The most powerful geomagnetic storms are usually triggered by events known as coronal mass ejections, or CMEs, during which billions of tons of plasma with embedded, interplanetary magnetic field are ejected from the outermost part of the sun's atmosphere, called the corona.

Most geomagnetic storms are mild and tend to have relatively minor impacts on Earth, but the more powerful ones, which are rare, can wreak havoc with technological systems.

Geomagnetic storms (which can last anywhere from hours to days) heat and distort the ionosphere, causing interference with long-range radio communication as well as global-positioning systems (GPS). This can lead to navigation errors in the case of the latter.

On the ground, these events can result in power grid surges, which have led to widespread blackouts, such as those that occurred during a strong geomagnetic storm in 1989. Due to the threat of such events, electric power companies have measures in place to mitigate any potential damage.

But, it's not all bad.

These storms also produce stunning aurora, more commonly known as the Northern or Southern Lights. These spectacular phenomena arise when charged particles spewed out by the sun slam into atoms and molecules in the Earth's atmosphere, heating them up and producing light.

What is a Radio Blackout Event?

Every so often, a giant magnetic eruption will occur in a localized region of the sun's atmosphere, known as a solar flare. These events, which arise near sunspots, spew out electromagnetic radiation, such as X-rays, visible light and ultraviolet light.

Some of this radiation can reduce the ability of the ionosphere to reflect long-range radio waves, resulting in radio blackout events. This can affect industries such as the aviation and maritime sectors, which rely on high frequency radio communications.

Radio blackouts are among the most common space weather events to affect Earth. They are also the fastest to have an impact on our planet with the X-rays, which travel at close to the speed of light, arriving from the sun in just eight minutes following a solar flare.

The blackouts last for several minutes, but in some cases, they can continue for hours.

What is a Solar Radiation Storm?

Solar eruptions also spew out huge quantities of high-energy, charged particles, which can result in solar radiation storms lasting from a few hours to days.

While the Earth's magnetic field provides some protection from this radiation, this protection is not total, and in some areas, the energetic particles can penetrate our planet's defenses.

When this happens, the fast-moving particles are guided by the Earth's magnetic field lines toward the poles where they can penetrate the atmosphere.

A solar flare
A photograph taken from the Skylab space station in 1974 showing solar flare on the surface of the sun, caused by the sudden release of energy from the magnetic field. Solar eruptions can result in radio blackout events on Earth. E. Gibson/MPI/Getty Images

These particles can cause damage to the electronic circuits of spacecraft, and indeed, to the DNA of astronauts or other living things in space.

Some extremely powerful solar radiation storms can even expose passengers and crew flying in planes at high latitude and altitude to increased levels of radiation. These storms may also significantly interfere with high frequency radio communications in the polar regions.

Can We Predict Space Weather?

Piyush Mehta, an assistant professor of mechanical and aerospace engineering at West Virginia University, told Newsweek there are a few ways to protect people, technology and infrastructure from the effects of space weather depending on the context.

However, our ability to predict potentially serious events is still relatively limited.

"For example, if you're worried about radiation exposure when you fly on commercial airlines, then one way to protect against that could be to have the ability to better predict where the high radiation spots are on the flight path and try to avoid them," he said.

"But, we're not at a point where we can do that well yet."

Scientists monitor space weather using a mixture of spacecraft in orbit around the Earth and further afield, as well as ground-based observatories.

But while our understanding of space weather has improved tremendously over the course of the space age, there is still a long way to go before our modeling and prediction abilities are on par with those for weather on Earth.

"When we talk about space weather, people immediately start to connect it to what we do in terms of prediction for Earth weather," he added.

"We are much further ahead in terms of our understanding our ability to model weather on Earth. In terms of predicting space weather, we are in the infancy. That is kind of evident from the fact that we don't really do a good job at predicting most of the processes, especially during active events."