Are we ready for the next great solar storm?
It was only another night in September 1859 when Richard Carrington and Richard Hodgson witnessed a remarkable event. The British astronomers weren’t together, but both were scanning the Sun through telescopes at the exact moment a massive ejection occurred from the flaming star. Within days, others on Earth noticed colorful auroras crossing the sky and telegraph lines – the cutting edge technology of the time in Europe and North America – bursting into sparks.
The solar flare became known as the Carrington event, named after one of the two astronomers who first described it. Although it occurred over 150 years ago, it is still the strongest geomagnetic storm known (although we lack measurements to say precisely how big it was).
Since then, Earth has been impacted by a few significant geomagnetic storms, all of which have caused blackouts and damage to satellites. As a result, power companies and satellite manufacturers have built resistance into our technology. But what if another solar flare at the Carrington event occurs today? Would we be ready for it?
According to Alexa Halford, deputy head of the heliophysical sciences division at NASA’s Goddard Space Flight Center, the answer is a cautious yes. “There is still a lot to learn,” she says, “but we have been successful. ”
Decades of learning
Eruptions occur when electromagnetic radiation bursts out of the Sun. These gusts often last a few minutes, although they are sometimes longer. They are sometimes associated with coronal mass ejections, which blow gas and magnetic fields. But not all solar flares or coronal mass ejections will impact Earth; it depends on both the size of the gust and the direction in which it is heading. If a solar flare occurs on the other side of the Sun, for example, it is unlikely to affect us.
Even though this happens on the near side, we often miss the direction of the burst – because we are quite far away and a relatively small target relative to the Sun. This happened in 2001, for example, when one of the largest solar flares in recorded history exploded in a coronal mass ejection at a rate of about 4.5 million miles per hour. Fortunately, he swept by us on his way into space.
The technology was relatively straightforward in 1859 when the Carrington event happened, but it still had a big impact on telegraph lines. Back then, people had to unplug the wires to stop the sparks flying out of them. But they remained partly functional, thanks to the particles ejected from the torch which struck the current in the lines. “They actually had to unplug them, and they still had enough power and current to run for a while,” says Halford.
There have been previous solar flares whose impacts have been felt on Earth, of course. A solar storm that occurred in 993 AD left traces on tree trunks that archaeologists still use today to date ancient wooden materials, such as the brief Viking settlement in the Americas. Another major solar flare occurred during World War I. It wasn’t as big as the Carrington event, but it still confused the detection equipment. Techs believed bombs were falling when it was actually interference from the rocket illuminating the magnetosphere, Halford says.
A large coronal mass ejection recently hit Earth in March 1989, and the resulting geomagnetic storm wreaked havoc on Earth. The torch destroyed power grids in Quebec and parts of New England, while utility company Hydro-Quebec was down for nine hours. Power transformers even melted due to an overload of electricity in the grid.
This 1989 event finally caught the attention of infrastructure planners. “These are the kinds of things we’ve really learned our lesson from,” says Halford. Power companies have started to put security measures, such as tripwires, into the power grid to stop cascading blackouts. If the power rises too quickly, these tripwires are programmed to shut off so the damage is limited and the transformers don’t burn out like they did in 1989.
Geomagnetic storms can also cause bit reversals, surface charge, or internal charge from satellites orbiting our planet – all things that have happened. this month of october when a solar flare produced a coronal mass ejection and a geomagnetic storm that hit the Earth. Satellites are particularly sensitive because they do not benefit from the relative protection of our atmosphere. But most of the satellites launched over the past two decades have been built sturdy enough to withstand overload.
Bit flips occur when ionized particles in solar explosions change the function of memory bits. This can cause big problems for GPS satellites, affecting everything from navigation to precision drilling. Even banking services depend on GPS satellite to dictate the timing of transactions. “This kind of failure would really hurt the economy,” said Halford. “This is important and definitely something we should be worried about.”
Although the satellites are now built more robustly, she adds that a storm is unlikely to remove enough GPS satellites to cause many bigger problems. Sometimes these issues can also be easily resolved by power cycling or simply restarting the affected device. The October eruption caused a few minor issues, but the Federal Aviation Administration did not report any major navigation issues, Halford said.
Not all of the impacts of a large solar flare would necessarily be negative. When these events occur, they thicken the density of Earth’s upper atmosphere. This is because the atmosphere rises in altitude for a short time. This can impact the orbits of satellites, potentially causing problems, but it can also affect the orbits of space debris floating up there. The extra drag could knock this garbage into orbit and burn it.
“You want storms so we can naturally get rid of some of the debris,” Halford said. But it could be a double-edged sword, as the event could also cause the orbital disintegration of operating equipment there.
Another potentially positive effect for Earthlings living closer to the equator is the increased visibility of the aurora. The Northern Lights and Southern Lights are caused when solar particles enter the atmosphere and collide with gas particles. This usually happens at the poles, where the magnetic field is weaker. But during solar flares, more particles pass through the atmosphere. The Northern Lights were recently visible in New York during the solar storm of October.
These opportunities will only increase as we approach a solar maximum period, that is, when we see the greatest period of solar activity every 11 years or so. “The next few years should be really exciting because we’ll have a lot more chances to see the Aurora,” said Halford.
It could also be a likely time for another large solar flare to occur. According to Halford, this will be an opportunity to see how well our safety measures and precautions can cope with this influx of solar particles – but don’t hold your breath. A to study published in 2019 found that the probability of a Carrington-type event occurring before 2029 is less than 1.9%. “A Carrington event is one of those kinds of things that you kind of want it to happen,” says Halford, “because we think we can get over it.”