Aurora borealis over sea, snowy mountains on starry winter night. Northern Lights in Lofoten … [+]
Are the northern lights dangerous? Powerful geomagnetic storms in May and October brought intense aurora borealis displays across the US as far south as Arizona and Florida. May was the strongest for perhaps hundreds of years. What’s going on?
There’s a lot of fear online about the sun’s activity as it reaches its (eventually natural) solar maximum — an event that happens once every 11 years — but rest assured that observing the Northern Lights is perfectly safe for observers. They occur hundreds of miles up in the atmosphere and pose no threat to humans below.
However, electrically charged particles produced during geomagnetic storms can damage infrastructure – and experts are growing increasingly concerned.
Northern Lights Warning: Solar flares and coronal mass ejections
Space weather is divided into two major events on the sun’s surface that can have consequences for Earth – solar flares and coronal mass ejections. Both are rising this year because the sun is now at its solar maximum.
Solar flares are powerful bursts of radiation that typically erupt from sunspots on the sun’s surface and travel at the speed of light. If directed at Earth, they arrive in just over eight minutes and cause a geomagnetic storm. Small events regularly cause radio outages for sailors and shortwave radio users, which can cause radio outages. “The major impact of a solar flare is usually on GPS systems on the order of about a minute, which is generally not a big problem,” said Andy Gerrard at the New Jersey Institute of Technology’s Center for Solar-Terrestrial Research. in an interview. “Pilots have backup tools to land, take off and steer the plane.”
Coronal mass ejections are large clouds of magnetic fields and plasma ejected into space at up to 1,900 miles (3,000 kilometers) per second. They usually follow a significant solar flare. A CME can cause a geomagnetic storm if it is headed toward Earth. It can change the shape of the Earth’s magnetic field to create spectacular aurora displays. “A coronal mass ejection lasts two or three days, so we have time to prepare, but it could easily miss Earth,” Gerrard said.
Infrastructure damage occurs when a solar flare or CME is particularly powerful. This happened last May, when a “halo CME” saw several CMEs traveling at different speeds arrive at Earth at the same time.
Northern Lights Warning: One Night in May
May’s G5-rated geomagnetic storm event wasn’t as strong as it could have been, but it had unexpected consequences. In addition to the pressure on SpaceX’s Starlink broadband internet satellites, the increase in charged particles affected GPS satellites, compromising the accuracy of critical GPS navigation systems used in modern agriculture.
“GPS receivers work when a signal is received at regular intervals, much like a beat from a metronome, from an orbiting satellite,” said Tim Marquis, a senior product manager at John Deere. “During solar storms, that signal hits a ‘fog’ of charged particles and can get lost. And cars can’t know exactly where they are thanks to this interference.”
Aurora Forecast – Cue NOAA’s 30 Minutes is not designed to help aurora hunters, but rather those who monitor infrastructure that needs protection.
May’s event may have been relatively powerful, but it was nothing compared to what could happen. Planet-wide aurora-involving solar superstorms are considered once-in-a-century events and, as luck would have it, have yet to occur in the modern era. The three major solar storms in human history all occurred in succession—in 1859, 1872, and 1921—now more than a century ago.
Northern Lights Warning: The Carrington Event
The most intense solar storm was the so-called “Carrington Event” on September 2, 1859, when astronomer Richard C. Carrington observed a burst of white light from the sun for about five minutes. It was the most significant solar flare ever recorded, an X45, and later produced global auroras. However, it caused little trouble in pre-industrial society, apart from electrocuting telegraph operators. “As far as we know, it was one of the biggest storms to hit Earth in the last 200 or 300 years,” Gerrard said. “There are news reports at the time when the aurora was almost a global phenomenon.”
In the past, a massive once-a-century solar storm could occur without incident, but a solar storm of similar intensity can now have profound effects. The most convincing evidence is what happened in Quebec, Canada, in 1989 when a solar storm knocked out the power grids. “Back then, the power grid was more sensitive because it was more interconnected,” Gerrard said. “If one area went down, other networks would pick up that load.”
During that event, there was a grid surge in the northeastern US that caused transformers to fail simply because the load was much greater than expected under normal circumstances. “Since 911, many networks, not just in the US but around the world, have had fast disconnects, so if the load gets too high going from one network to another, they will disconnect themselves immediately,” Gerrard said. “You won’t have that burn.”
A solar storm of similar intensity to the 1859 “Carrington Event” may now have deep … [+]
Northern Lights Warning: What would happen now?
If there was a giant solar storm right now, local networks would be down, but they would likely be fixed in a day or two. “You can bring in transformers, repair equipment and repair crews from other areas,” Gerrard said. However, this may be impossible during a repeat of a Carrington Event-scale solar superstorm.
A study published by Lloyd’s of London and Atmospheric and Environmental Research in 2013 suggested that a massive solar storm of Carrington strength could cost $2.5 trillion, with its effects lasting over a year. A major event could even affect the Internet’s vast network of undersea cables.
“You’re not just going to lose a power grid; you’re going to lose power grids around the world,” Gerrard said. “Where do we get up? Where do we find the reserves? Where do we find transformers? How to repair the electrical network? How to repair transatlantic cables, communications – you name it.”
Are we ready for another Carrington event? “Every country is a bit at a loss and unprepared for such a scenario,” Gerrard said. The probability of the “big one” happening is low, but we know from the geological record that they are inevitable. “They are more frequent than a near-Earth asteroid,” Gerrard said. “There will be one in the next 200 years.”
Northern Lights Alert: Challenge for Forecasters
“It’s always a challenge for us because everybody loves the aurora borealis, and the bigger the storm, the further south it’s visible,” said Bill Murtagh, National Oceanic and Atmospheric Administration Program Coordinator. Space Weather Forecast by the National Atmospheric Administration (NOAA), at a press conference in October.
The problem is that space weather forecasters must rely on models for much of the two- or three-day journey of CMEs from the sun to Earth. How fast is the CME traveling? Is it, in fact, headed for Earth? Forecasters have real-time data only after the CME hits NASA’s DSCOVR and ACE satellites about a million miles from Earth’s orbit. They measure the speed and magnetic intensity of a CME, which is critical in calculating how the solar wind will change. Depending on the speed of the CME, satellites give only 15-30 minutes warning of a significant space weather event – and the resulting displays of the northern lights.
Murtagh knows everyone gets excited about the aurora, but “at the same time, we can’t hope for these big displays because they threaten our critical infrastructure,” he said. “We should always be careful what we wish for.”
I wish you clear skies and open eyes.