XILINGOL, CHINA – MAY 12: Northern lights shine over the trees during the Xilingol League in Inner Mongolia, China, on May 12, 2024. People in China have been amazed by the unusual and spectacular display of the northern lights (also known as the aurora borealis), which is the result of an upcoming severe solar storm that is expected to continue in the coming days. Credit – VCG via Getty Images; 2024 VCG
IIt has been a season of sky shows. A lunar eclipse was observed on March 24 and 25 in America, Europe, and Northern and Eastern Asia. April 8 saw a total solar eclipse in North America. The months of March and April also bring the appearance of the evocatively named Devil’s Comet. And last weekend, earthlings were treated to a spectacular light show when a geomagnetic burst on the sun known as a coronal mass ejection created a colorful display of the aurora borealis, a phenomenon usually limited to the northern polar region but this time visible. As far south as Alabama in the USA and at similar latitudes around the world.
Coronal mass eruptions are not just a spectacle, they also produce potentially deadly mischief. When energy from the sun collides with the Earth, it can disrupt satellites, flip GPS systems, disable power plants and shut down telecommunications. Like hurricanes, solar storms are ranked by the National Oceanic and Atmospheric Administration (NOAA) into five categories, from minor to moderate, strong to severe, and extreme.
On May 12, NOAA issued a rare severe to extreme warning about the developing event, but even at its peak between May 10 and 12 there were no reports of power or satellite outages. But if Earth dodges a bullet this time, we’ll be facing a potentially challenging year as the Sun goes through one of its most intense activity cycles.
So what’s going on out there, how big is the danger to us on Earth, and how can we prepare?
What causes solar storms?
Just as the earth has its seasons, so does the sun. But solar seasons do not occur over the course of months, but rather in 11-year cycles that produce times of high activity, known as solar maximum, and times of low activity, known as solar minimum. The cycles are due to the fact that the sun is not solid, which means that different parts of its surface rotate at different speeds; It takes 25 days to complete a single rotation at the equator and 33 days at the poles. This causes the sun’s magnetic field to become entangled and slowly build up energy until it breaks. When this happens, the north and south magnetic poles switch places, releasing energy that creates a solar maximum. Once this energy is spent, the sun returns to a less volatile solar minimum.
One indicator of high solar activity is sunspots, small patches of bent magnetic fields on the sun. The greater the number of dots, the greater the volatility of the sun. The current eruption was associated with a sunspot 16 times the diameter of the Earth and emitted billions of tons of plasma (superheated gas composed of charged particles).
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However, not every solar maximum or solar minimum is equal. “The sun’s main cycle is 11 years, but people have noticed longer-term trends in sunspot activity,” says Michael Liemohn, professor of climate and space sciences and engineering at the University of Michigan. “There appears to be a century-long cycle in which the number of sunspots at the Sun’s maximum becomes fewer for a cycle or two and then returns to a more normal level.”
The last period of the solar maximum, which ended about a decade ago, was at the lower end of the energy spectrum. The one that ended 20 years ago was higher. “We expect this current solar maximum to be larger than the previous one and more similar to the solar activity peak 20 years ago,” says Liemohn.
How coronal mass eruptions endanger Earth
The best way to understand the impact of solar storms on our planet is to compare the atmosphere to the gas in a fluorescent bulb. Liemohn explains that electrodes at each end of the bulb accelerate electrons that interact with the gas, energizing it and causing it to emit light. High in the atmosphere (50 to 200 miles above) a similar process creates the aurora. The closer you get to the Earth’s surface, the less harmless the effect is.
“Just like in the light bulb, there is an electric current associated with the fast electrons, and these space currents can induce other electric currents in conductive loops here on the ground,” Liemohn says. “The loops need to be very long, many kilometers, but high voltage power lines are susceptible to this effect.”
Damage to satellites is more direct and is done in a variety of ways. As NASA’s Goddard Space Flight Center explains, geomagnetic storms heat the outer atmosphere, causing it to expand. This increases drag on the satellites and can disrupt their orbits. Charged particles emitted from the sun during a solar storm can also penetrate a satellite or electrocute its surface, damaging its components. The problem is especially acute for satellites in high orbits, more than 22,000 miles above Earth (the altitude at which most communications satellites fly).
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Crewed spacecraft like the International Space Station orbit much lower, usually about 250 miles above. This gives astronauts some protection from Earth’s magnetosphere; This protects us from sunlight and cosmic rays on the ground. Still, astronauts receive higher radiation doses than earthbound humans and animals, especially during solar storms. The station or spacecraft itself provides additional protection; But an unprotected astronaut on the surface of the moon or Mars could face serious problems during a solar storm. According to Space.com, the coronal mass ejection “shockwave” would subject the astronaut to the equivalent of 300,000 simultaneous chest X-rays; this is much more than the 45,000 that proved fatal.
We’re getting ready for the next one
Typically, a solar storm takes about a day to reach and pass Earth. Liemohn explains that the last one lasted several days because the sun brought out several storms in succession. He said on May 12: “The world is currently in the recovery phase of the storm, and this storm will continue for a few more days.” “But now the aurora will be confined to its usual location at higher latitudes across Alaska and Canada.”
Larger storms are likely to occur during this strong solar maximum. According to NOAA, it could take until mid-2025 for solar weather to begin to wane. So how can we prepare?
In 2019, Congress made a move to harden America’s defenses against space weather events by passing the PROSWIFT Act to Promote Space Weather Research and Observations to Improve Tomorrow’s Forecast. Under the law, Washington authorized NOAA, NASA, the National Science Foundation, industry, academia and more to study how to prepare for adverse space weather events and to prioritize appropriate funding for that purpose.
“Basically,” says Daniel Welling, an assistant professor of climate and space sciences at the University of Michigan, “the act is to have these agencies advise the nation on how to go about understanding space weather forecasts and setting benchmarks.”
This is not easy to do right now. First of all, space weather is still something of a black box for researchers. Second, even if we could predict terrestrial weather as reliably as we can predict terrestrial weather, the U.S. power grid is so expanded and regionalized that it’s difficult to put protocols in place to protect everything.
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But New Zealand has a proof-of-concept example of what this type of command and control system would look like.
Just over a year ago, Welling worked with a team at Transpower, which owns and operates the country’s national grid.
modeling an extreme solar storm forecast and then changing the grid configuration until it stabilizes. This was reduced to a PDF procedure available on the desks of Transpower operators. “They enabled this [past] weekend,” says Welling, “which is really cool.”
But a country of 5.1 million people covering 103,500 square miles is different from a country like the United States, with a population of 333 million and an area of 3.8 million square miles. If a grid-destroying storm hits, our power systems will likely collapse. However, this is not due to a lack of machines and protocols in development. Power plant transformers operate on alternating current, but direct current surges may occur during solar storms.
“These transformers are not meant to handle that, so sometimes they can get hot pretty quickly,” Welling says.
A piece of hardware known as a geomagnetically induced current (GIC) suppressor can be installed to protect transformers from destructive power pulses. The problem is that GIC blockers are still under development and like that when established, they can have what Welling calls the Whac-A-Mole effect. “You turned off the current [from the solar storm] it doubles here and doubles there,” he says.
This leaves transformers vulnerable, and vulnerable transformers are a very bad thing. “Transformers are the size of your living room, custom-made, and shipped from overseas,” says Welling. If they are damaged or destroyed during a storm, “it can take weeks or longer for them to recover,” he adds.
Potential satellite damage is easier to manage. One of the biggest risks here is ghost commands that cause satellites to behave abnormally. The solution is to send them repeated “spam commands”, basically reminding them over and over again to keep working as they should. Careful tracking of the orbit can allow operators to fire the satellites’ thrusters in appropriate bursts, preventing orbits from being disrupted by atmospheric drag.
Both oil pipelines and railway systems can also cause problems, as any long, metal, ground-based conductor can carry current during a geomagnetic storm. When it comes to pipelines, there’s not much controllers can do other than monitor them, looking for damage the current might cause. When it comes to trains, rail traffic controllers know not to rely on automatic signals during a geomagnetic storm and will instead take over manually, Welling says. A similar rule applies to the oil industry and some aspects of the military that are heavily dependent on GPS systems.
“These industries will suspend operations until everything becomes clear,” Welling says.
Air traffic controllers must also react, diverting aircraft away from areas where communication disruptions are occurring or grounding aircraft entirely if the lack of communications is more global. Passenger health will also require avoiding areas where high levels of hazardous radiation are present.
Last weekend, Welling says, “flights that normally fly over the pole were diverted to lower latitudes due to the risk of radiation.”
For now, these decidedly flawed protocols are the best measures the US and most of the rest of the world have. Not only do better preventive and corrective solutions need to be developed, but the business of space weather forecasting also needs to evolve dramatically. And this can take a lot of time.
“There’s a rumor that space weather is 50 years behind meteorology in terms of forecasting and statistics,” says Welling. “Events [last] The weekend really made this quote resonate with me.
Contact us at letters@time.com.