The Northern Lights may be visible in parts of the US this weekend. Why are they so active now?

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A series of solar flares and coronal mass ejections from the Sun have the potential to create dazzling auroras that can be seen as far south as Alabama and Northern California, but could also disrupt communications on Earth tonight and this weekend, according to the National Oceanic and Atmospheric The Administration’s Space Weather Prediction Center.

The center, a division of the National Weather Service, has issued a severe geomagnetic storm warning for Friday evening. It is the first watch of this type since January 2005.

As the sun approaches the peak of activity in its eleven-year cycle, known as solar maximum, later this year, researchers have observed increasingly intense solar flares erupting from the fiery orb.

Increased solar activity causes auroras that dance around Earth’s poles, known as the Northern Lights, or aurora borealis, and Southern Lights, or aurora australis. When the activated particles from coronal mass ejections reach Earth’s magnetic field, they interact with gases in the atmosphere to create different colored light in the sky.

The Space Weather Prediction Center has been monitoring several strong outbursts since Wednesday that came from a large cluster of sunspots on the solar surface. The cluster has a diameter of sixteen times the diameter of the Earth.

Scientists have observed at least five coronal mass ejections, or large clouds of ionized gas called plasma and magnetic fields, erupting from the Sun’s outer atmosphere and being released from the Sun toward Earth. These significant eruptions are expected to occur as early as Friday afternoon and continue through Sunday.

Forecasters won’t know the storm’s true intensity until it arrives about 1.6 million kilometers from Earth and reaches satellites that monitor space weather, which is estimated to happen Friday around 8 p.m. ET, said Shawn Dahl, the service coordinator for the Space Weather Prediction Center.

After determining the intensity, forecasters can issue additional warnings, Dahl said.

NASA's Solar Dynamics Observatory captured this image of a solar flare in extreme ultraviolet light on May 2.  The solar flare is the bright flash towards the upper central part of the sun.  -NASA/SDO

NASA’s Solar Dynamics Observatory captured this image of a solar flare in extreme ultraviolet light on May 2. The solar flare is the bright flash towards the upper central part of the sun. -NASA/SDO

The center’s space weather scale includes three categories: solar flares that cause high-frequency radio blackouts, geomagnetic storms and solar radiation storms.

According to the center, current solar activity could cause a solar radiation storm.

“That’s the bottom of our scale,” Dahl said. “It does mean something for some rocket launch operations and satellite operators. But right now, there’s nothing that can’t be dealt with, as far as we understand it. The potentially stronger events obviously exist and we will see if they materialize.”

The peak of geomagnetic storm activity on Earth could occur between 2 a.m. and 5 a.m. ET on Saturday, the center has predicted.

The center called this “an unusual event.” There have been three geomagnetic storms since December 2019, but all are considered weak, according to the center.

Solar-driven geomagnetic storms in recent months have caused auroras to become visible in places where they are rarely seen, including as far south as New Mexico, Missouri, North Carolina and California in the United States, and southeastern England and other parts. of the United Kingdom.

Depending on the location, the auroras may not always be visible overhead, but keep an eye on the horizon, experts say, because they can create a colorful display there too.

Even if auroras aren’t visible in the sky, experts at the center recommend taking photos of the sky with your phone, because the images may capture what you can’t see with the naked eye.

The Northern Lights can be seen on the northern horizon in the night sky over Wolf Lake in Minnesota's Cloquet State Forest in September 2019.  -Alex Kormann/Star Tribune/Getty ImagesThe Northern Lights can be seen on the northern horizon in the night sky over Wolf Lake in Minnesota's Cloquet State Forest in September 2019.  -Alex Kormann/Star Tribune/Getty Images

The Northern Lights can be seen on the northern horizon in the night sky over Wolf Lake in Minnesota’s Cloquet State Forest in September 2019. -Alex Kormann/Star Tribune/Getty Images

The effects of geomagnetic storms

When directed toward Earth, these emissions can cause geomagnetic storms or major disruptions to Earth’s magnetic field.

“Geomagnetic storms can impact infrastructure in orbit and on the Earth’s surface, potentially disrupting communications, power grids, navigation, radio and satellite operations,” the Space Weather Prediction Center said. “(The center) has notified the operators of these systems so that they can take protective measures.”

IIn turn, operators ensure power lines perform as expected, ensure alternate equipment is available and functioning and that all maintenance is suspended, Dahl said.

“But the most important element here is that they know what the cause is when the situation arises, which allows us to take the appropriate steps to help mitigate and manage the developing problems,” Dahl said.

When coronal mass ejections arrive, they carry their own magnetic field, which can overwhelm power lines and generate electrical currents, so operators can watch for signs of such activity, says Rob Steenburgh, a space scientist at the Space Weather Prediction Center.

“When we talk about the impact on the electricity grid, we are talking about the high-voltage transmission lines. That is where these currents can develop. It’s not on any line that goes from a small transformer to their house,” Dahl said. “It only really develops on the high-voltage lines, which causes problems for the large transformers that control the distribution.”

Solar storms generated by the sun can also cause radio interference and even pose risks to manned space missions.

NASA’s Space Radiation Analysis Group monitors conditions for astronauts aboard the International Space Station. If there appears to be an increased radiation risk, the astronauts can move to parts of the station that are better shielded.

The center warned that additional solar activity could cause geomagnetic storms to persist through the weekend.

So far, researchers have observed only three severe geomagnetic storms during the current solar cycle, which began in December 2019, according to the center.

Previously, a G5, or extreme geomagnetic storm, occurred in October 2003, causing power outages in Sweden and damaged power transformers in South Africa, the center said.

Experts at the center say they are “a little concerned,” but mainly because such events are rare.

The team likened it to preparing for a summer storm: keep batteries and a weather radio on hand in case the power goes out, but said people don’t need to do anything unusual to prepare for space weather. No disruption to internet or cell service is expected. And the disruption to GPS is not expected to last long as long as providers can quickly take advantage of satellite signals again, the center’s experts said.

Tracking space weather

About every eleven years, the sun experiences periods of low and high solar activity, which is related to the amount of sunspots on its surface. The sun’s strong and constantly changing magnetic fields drive these dark regions, some of which can reach the size of Earth or larger.

Over the course of a solar cycle, the sun will transition from a calm to an intense and active period. During the peak of activity, called solar maximum, the sun’s magnetic poles reverse. Then the sun will become silent again during a solar minimum.

Solar maximum is expected to peak in mid to late 2024, but the sun will remain active for a few years after that.

Teams at the Space Weather Prediction Center use data from ground-based and space-based observatories, magnetic maps of the Sun’s surface, and ultraviolet observations of the Sun’s outer atmosphere to determine when the Sun is most likely to have solar flares, coronal mass ejections, and will emit bursts from the sun. other space weather that could affect Earth.

Solar flares can affect communications and GPS almost immediately, because they disrupt Earth’s ionosphere or part of the upper atmosphere.

Energetic particles released by the sun can also disrupt electronics in spacecraft, affecting astronauts without proper protection within 20 minutes to several hours.

The material sent away from the Sun during coronal mass ejections can arrive at Earth between 30 and 72 hours later, creating geomagnetic storms that affect satellites and create electric currents in the upper atmosphere that travel through the ground and can have an impact on the electrical energy. grids.

The storms also affect the flight patterns of commercial airlines, which are ordered to stay away from Earth’s poles during geomagnetic storms due to loss of communications or navigation capabilities.

Extreme storms have occurred before, such as the storm that knocked out Quebec’s power grid in 1989 and the Carrington Event of 1859. The latter storm remains the most intense geomagnetic storm on record, causing telegraph stations to spark and catch fire.

If such an event were to occur today, it could cause trillions of dollars in damage and shut down some power grids for a significant period of time.

Correction: An earlier version of this story misstated the date of a previous G5 storm.

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