A dramatic eruption from the sun on Friday created the strongest magnetic storm in Earth's atmosphere, making the aurora visible as far as Florida and Southern California and potentially disrupting power grids, communications and navigation systems. .
This is the strongest storm of its kind to reach Earth since Halloween 2003. It was strong enough to cause power outages in Sweden and damage transformers in South Africa.
The effects could last into the weekend as a steady stream of ejecta from the sun continues to collide with Earth's magnetic field.
The solar activity is so strong that the National Oceanic and Atmospheric Administration, which monitors space weather, issued an unusual storm watch for the first time in 19 years, which was later upgraded to a warning. The agency began observing explosions on the sun's surface on Wednesday, with at least five heading toward Earth.
“What we're expecting in the next few days should be more significant than anything we've certainly seen to date,” said Mike Betwee, director of operations for NOAA's Space Weather Prediction Center. He said this at a press conference on Friday morning.
For people in many places, the most visible of the storms will be the Northern Lights, also known as the Northern Lights. But authorities and businesses will also be watching the impact on infrastructure such as global positioning systems, wireless communications and even electricity.
The Northern Lights are most often seen at high latitudes near the North Pole, but people in more parts of the world have already seen the show this weekend, which could continue into early next week.
As Friday turned into Saturday in Europe, people across the continent described the sky as mottled.
Alfred CarpinettiThe astrophysicist, journalist and author, who lives in north London, witnessed them with her husband from the roof of their flat.
“Being able to see the Northern Lights directly from your own backyard is incredible,” he said. “We were hoping to see a glimpse of green on the horizon, but the sky was filled with both green and purple.”
Here's what you need to know about this weekend's solar event.
How will the storm affect people on Earth?
A geomagnetic storm watch or warning indicates that space weather may impact critical infrastructure orbiting on or near Earth. Additional current flows into the system, potentially damaging pipelines, railroad tracks, and power lines.
Telecommunications that rely on high-frequency radio waves, such as amateur radio and commercial aviation, are most likely to be affected, said Joe Lama, an astronomer at the Lowell Observatory. This means cell phones and car radios that rely on higher frequency radio waves are less likely to fail.
Power outages may still occur. As with any power outage, you can be prepared by charging your devices and having access to backup batteries, generators, and radios.
The most notable solar storm recorded in history occurred in 1859. The phenomenon, known as the Carrington phenomenon, lasted for nearly a week, produced the aurora borealis, spread to Hawaii and Central America, and affected hundreds of thousands of miles of telegraph lines.
But it was a 19th-century technology, used before scientists fully understood how solar activity disrupts Earth's atmosphere and communication systems.
“That was an extreme event,” said Sean Dahl, a forecaster with NOAA's Space Weather Prediction Center. “We don't expect that.”
Unlike tornado watches and warnings, NOAA's announcements are not intended for the general public.
“For most people on Earth, there's no need to do anything,” says Rob Steenberg, a space scientist at NOAA's Space Weather Prediction Center.
The purpose of this announcement is to give government agencies and companies that operate this infrastructure time to take safeguards to reduce the impact.
“If everything is working properly, the grid will be stable and we can go about our daily lives,” Steenberg said.
Will I be able to see the aurora borealis?
This week, the Northern Lights could grace the skies in places they aren't normally seen. The best visibility is outside the bright lights of a city.
Clouds and inclement weather can cause problems in some locations. However, if the skies are clear, even well south of where the northern lights are expected to occur, take a photo or record a video with your phone. Camera sensors are more sensitive to the wavelengths produced by the aurora borealis, which can produce images that are invisible to the naked eye.
If the sky is clear, you may even be able to see sunspots during the day. As always, do not look directly at the sun without protection. However, if you still have the eclipse glasses you used for the April 8 event, you can also use them to try to find the cluster of sunspots that is causing this activity.
How strong is the current geomagnetic storm?
Giant explosions on the sun's surface, known as coronal mass ejections, send streams of high-energy particles into space. However, the Sun is large, so such an explosion may not be able to cross our planet as it travels around the star. However, when these particles cause disturbances in the Earth's magnetic field, it is known as a geomagnetic storm.
NOAA classifies these storms on a “G” scale of 1 to 5, with G1 being minor and G5 being extreme. The most extreme storms can cause widespread power outages and damage to infrastructure around the planet. During these events, satellites can also have problems orienting themselves or sending and receiving information.
The current storm is classified as G5, or “extreme.” It is caused by a collection of sunspots (dark, cool regions on the sun's surface) that are about 16 times the diameter of Earth. The cluster flares up and releases material every 6 to 12 hours.
“We expect a series of shocks over the weekend,” said Brent Gordon, director of Space Weather Services at NOAA's Space Weather Prediction Center.
Why is this happening now?
The sun's activity waxes and wanes on an 11-year cycle, and we are currently approaching the period of maximum solar activity. Three other severe geomagnetic storms have been observed so far in the current activity cycle, which began in December 2019, but none are expected to have a strong enough impact on Earth to warrant warnings or alerts. It has not been.
The sunspot cloud causing the current storm is the largest seen this solar cycle, NOAA officials say. They added that activity this cycle exceeded initial expectations.
Further flares and ejections are expected to occur from the cluster, but due to the rotation of the Sun, the cluster will be directed to a location where it is less likely to impact Earth. Sunspots may reappear on the left side of the sun in the coming weeks, but it is difficult for scientists to predict whether this will cause activity again.
“Typically these don't pack as much of a punch as the original,” Dahl said. “But only time will tell.”
Jonathan O'Callaghan I contributed a report from London.