A dazzling display of auroras could grace the northern skies Wednesday through Friday after the sun blasted several energy waves toward Earth earlier this week. Activity is expected to peak Thursday through Friday as a strong geomagnetic storm, rated G3, reaches Earth.
A strong G3 storm “brings the Northern Lights to the United States,” said Bill Murtagh, the program coordinator for the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center. He said skygazers could see the dancing light from New England across the Great Lakes to northwestern Oregon and Washington state.
At least, if clouds are not a problem.
On Wednesday, sky watchers in the Upper Midwest and New England may see too much cloud to get a good view of the aurora. On Thursday, when the geomagnetic storm is expected to be strongest, scattered cloud still appears likely over parts of the country’s northern stratum, although much of Montana, Michigan, New York, Massachusetts, Connecticut and Rhode Island will all be covered. predicted to have mostly clear skies.
Auroras are created when the sun sends a burst of energy and particles to Earth via solar flares, coronal mass ejections or solar wind currents. Some solar particles collide with Earth’s magnetosphere and travel along the magnetic field lines to Earth’s upper atmosphere, where they can excite nitrogen and oxygen molecules and release photons of light — creating displays known as the Northern Lights.
In this case, several coronal mass ejections (CMEs), or large expulsions of plasma and magnetic material from the sun, were created in a particularly active region of the sun over the past few days. The coronal mass ejections come just below a giant coronal hole that spans the northern and southern hemispheres of the sun. A coronal hole spews out a fast solar wind full of particles that can only cause some minor geomagnetic disturbances on Earth.
Much of the solar energy is directed toward Earth and is expected to generate moderate to strong geomagnetic storms. NOAA’s Space Weather Prediction Center released geomagnetic storm watches for Earth Wednesday through Friday.
“There is a lot of excitement from solar physicists and space weather people, but there is no concern. There is nothing to worry about; there is no imminent danger coming,” said Alex Young, associate director for science at the Heliophysics Science Division. from NASA’s Goddard Space Flight Center, adding that late Tuesday night, the first CME had only minor impacts on Earth.
Several solar flares have caused minor radio interference in recent days. Larger solar storms can also disrupt GPS systems.
On Thursday, the increased activity will be attributed to a “cannibal CME” event, which occurs when a faster-moving CME takes in a slower one. Coronal mass ejections can move anywhere from 1 million mph to 6 million mph as they travel through space, meaning a faster-moving CME can easily overtake a slower one before it reaches Earth.
“When the slower [CMEs] are launched first, and the faster they catch up, they can have even more impact,” space weather physicist Tamitha Skov explained on a YouTube livestream, adding that the term isn’t her favorite way to explain the phenomenon, though.
“Cannibalism is not really true, [CMEs] don’t really eat each other,’ said Skov. “All they can do is plow into each other like bumper cars and crash into each other and magnify each other.”
More solar storms are expected as the sun continues its 11-year solar activity cycle, reaching its maximum, which Murtagh expects to reach between 2024 and 2025.
“Since we started ramping up the solar minimum, we’ve had some G3-type storms, but we haven’t had any bigger than that. We haven’t had a G4 or higher geomagnetic storm at this stage of the cycle,” Murtaugh said. “But that is inevitable. We will see that level of storming in the coming months and years.”
Geomagnetic storms are categorized via NOAA’s G-Scale, a tool that runs from G1, a minor disturbance from the sun, to G5, an extreme storm that can cause widespread blackouts, knocking out satellites for days and making the aurora borealis visible far into the south as Texas and Florida.
Certain parts of the Earth seem to be more at risk from solar weather than others. A combination of local geology, proximity to the ocean, latitude and large interconnected power grids all play a role in calculating which areas are most at risk from disturbances caused by geomagnetic storms, Murtagh said.
“One of the most vulnerable areas in the world is the Northeastern Corridor of the United States,” Murtagh said, adding that parts of Canada are also quite vulnerable to solar storms.
The last G5 storm to hit Earth struck in 2003, with coronal mass ejections around Halloween. The storm damaged satellite systems, cut power to parts of Sweden for an hour and sent the aurora borealis south to Florida, NASA said.
Another disruptive solar storm struck in March 1989, causing significant disruption to global communications networks and shutting off power in much of Quebec for 12 hours.
“Just like people who live in areas where there are hurricanes or tornadoes, it’s always good to have flashlights, to have extra batteries, to put some water aside, because it’s true that recent research papers have shown that the geology is such Which [the Northeast] a little more sensitive,” said Young.
Kasha Patel contributed to this report.