Fresh waves of green and purple auroras could twinkle the night sky over parts of the continental US tonight, visible as far south as Iowa, Pennsylvania and Oregon as a powerful geomagnetic storm hits Earth. It’s the latest demonstration in an already chaotic year for space weather.
of NOAA Space Weather Prediction Center issued a geomagnetic storm watch for September 16, 2024, noting that the storm may Reach G3 or “strong” power. This is the level where power systems at high latitudes can set off high-voltage alarms, where navigation instruments must account for interference and the spacecraft may need to adjust to stay aloft. Solar wind waves will also expand Aurora’s reach.
The current wave of celestial activity began last week at a distance of 93 million miles Giant sunspots Our friendly neighbors are on the stars. Sunspots are patches of sun on the surface Unusually strong magnetic field And they appear as dark spots. This scar border is ripe for storms solar flareLarge bursts of radiation. They also swell Coronal mass ejectionsA burst of magnetized plasma from the Sun’s corona, its outer layer.
D Sunspot is a huge learning set off That sprays the solar system with high energy particles. When these particles collide with Earth’s atmosphere, they create a phenomenon similar to how neon lights work, exciting gases in the atmosphere and illuminating them, creating auroras.
They’re usually near the Earth’s poles (hence the “northern lights”), but if enough energetic solar particles charge the sky, auroras can reach much closer to the equator, which is why we’ve been seeing them all over the world lately.
This year, the Sun is at the peak of its activity cycle.
Roughly every 11 years, the Sun’s magnetic poles reverse and as it reverses there is more magnetic activity and thus more sunspots on the surface.
Anticipating how this activity will affect our home planet is an important task, not only because we Earthlings can get our cameras ready and ooh and aah at the colors of the night; Space weather can cause problems for communications, navigation and power grids.
Michael WiltbergerThe deputy director of the High Altitude Observatory at the National Science Foundation’s National Center for Atmospheric Research noted that predicting space weather is a lot like predicting terrestrial weather. The weather we normally experience on the ground is driven by heat, humidity and wind while space weather is driven by the electromagnetism of the stars and planets. But both space and terrestrial weather emerge from a confluence of short- and long-term drivers in different regions of the world. Although we don’t normally experience space weather on the ground, it creates a constant explosive mix of subtle and severe effects on our modern world equipment.
“There’s always something going on that affects a wide range of things, from radio communications to the lifespan of satellites to radiation risks for astronauts in space,” Wiltberger said.
And like your local TV meteorologists, scientists studying space weather draw on a variety of instruments and models to produce useful forecasts, including bulletins and visuals. On its website, the Space Weather Prediction Center Makes predictions “Essential to the space weather community” such as aviation, emergency management, satellite and space weather enthusiasts.
The key tools for space weather forecasting are spacecraft that observe the direction of the solar wind flow and magnetic field. “This is important because if it were aligned with the Earth’s magnetic field, we wouldn’t be able to dump a lot of energy into the system,” Wiltberger said. “But if it’s in the opposite direction, the magnetic fields during these geomagnetic storms can interact and get more energy and more direct coupling.”
These measurements are then combined with readings from ground-based cameras and magnetometers and fed into models to determine how a turbulent sun would illuminate Earth.
At the moment, one of the main goals is to increase the lead time for predicting how disruptive a geomagnetic storm will be. Although scientists see coronal mass ejections days before they begin to impact Earth, they cannot easily determine the strength and direction of the magnetic field, which, again, is the key to how much energy Earth suddenly absorbs.
Even minor injuries from the sun can be influential. GPS, for example, relies on timing signals between satellites to determine position on the ground. A geomagnetic storm can cause delays in these signals, throwing off critical measurements. “If you’re driving your car, probably not a big deal,” Wiltberger said. “But if you’re doing Precision agriculture And you’re trying to use it to figure out where to put the water on the seed you just planted, and you need really good precision, that’s a concern.”
Satellites can be vulnerable to solar storms in other ways as well. On February 3, 2022, SpaceX has launched 49 Starlink Internet satellites in low Earth orbit, but the next day a geomagnetic storm hits. The storm increased the density of the atmosphere, causing unexpected drag and forcing most of the satellites to re-enter Earth’s atmosphere and burn up.
The company said it has a fleet of about 6,000 strong Starlink satellites Recent storms are fine weather.
One of the biggest concerns is what a strong solar storm could do to the power system. Wiltberger said one could imagine a huge, fast-moving coronal mass ejection hitting Earth just 24 hours after leaving the Sun.
If the magnetic field of this ejection is aligned in the opposite direction of the Earth, it will create a large change in the Earth’s magnetic field. A changing magnetic field, you may recall from your electromagnetism class, can induce a current in a conductor, such as, say, a power transmission line. This can then disrupt power delivery or trip parts of the grid offline.
Still, even a severe coronal mass ejection is unlikely to trigger a civilization-stopping blackout. “We’re probably not going to lose the power grid, but the power grid may actually have to take steps to bring more power generation capacity online, defer maintenance, things like that,” Wiltberger said.
And maybe losing a few lights on the ground for a while isn’t such a bad thing when the night sky lights up.
Update, September 16, 2:20 pm: This story was originally published on May 14, 2024 and has been updated to include details of aurora visibility following another geomagnetic storm.
