It has been one week since the world got a preview of what happens when vital tech systems suddenly go down: grounded flights, postponed surgeries and disrupted 911 call centers worldwide.

But experts say the chaos that ensued from a botched CrowdStrike software update was just a fraction of what could happen as a result of natural disasters or cyberattacks. In one doomsday scenario raised in the wake of last week's outage, a solar storm could wipe out internet access for weeks.

It's an alarming possibility that the most pessimistic scientists say is an eventual certainty: One day, the sun will send a massive magnetic field toward Earth that could take down the internet.

The catastrophe could happen at any time, but like other looming disasters, a devastating solar storm remains a constant, low-likelihood risk.

“It’s not something I worry about for tomorrow, but it’s on the radar that won’t surprise me if and when it happens,” said Douglas Leonard, an astronomy professor at San Diego State University. “It’s really ultimately up to the sun to decide.”

How can a solar storm cause an outage on Earth?

Solar activity has been ramping up lately after an extended period of minimal activity, Leonard said. We’ve seen the effects in recent months; coronal mass ejections, or CMEs, caused a stunning display of the northern lights across large parts of the U.S., much farther south than they are usually visible. 

"The sun has an 11-year cycle where it goes through maximum and minimum," Shannon Schmoll, director of the Abrams Planetarium at Michigan State University, told USA TODAY. "This results in the number of sunspots seen on the sun. Sunspots result from areas of the sun that have stronger magnetic fields."

When the sun’s magnetic field bursts, clouds of highly charged particles are released and can go in any direction, known as a CME. When the particles are headed directly toward Earth, that’s when we have a problem, Leonard said. Because of the way magnetic fields impact electric fields, the changing magnetic field can induce a current in our electrical system so large it could fry transformers and cause a blackout and disrupt our communications and GPS systems. 

The unlikely circumstances would all have to align perfectly to cause an outage some experts have dubbed an “internet apocalypse.” 

This has happened before, and it threw the telegraph system into disarray

In 1859, a British scientist named Richard Carrington observed an intense brightening of the sun. Though coronal mass ejections weren’t yet understood, modern experts believe the event he saw was the flare that preceded a series of extremely intense CMEs that headed directly for Earth. In the following days, northern lights were seen as far south as Cuba, according to NASA.

At the same time, the telegraph system, or the "Victorian internet," went on the fritz. Some telegraph offices even caught fire.

"A similar storm today could have a catastrophic effect," NASA said a decade ago.

More recently, in March 1989, a less severe geomagnetic storm knocked out power for about 6 million people in Montreal for hours. Some parts of the northeastern U.S. and Sweden also lost power.

And in October 2003, a series of solar storms hit Earth around Halloween, dazzling people in the U.S. as far south as Texas and Florida with a northern lights show, according to the National Oceanic and Atmospheric Administration. But it also caused serious disruptions or damage to satellites, GPS, and radio communication systems. Flights between North America and Asia going over the North Pole were disrupted, a Japanese satellite was destroyed beyond repair and science groups in Antarctica had a full communications blackout for several days.

How likely is an internet blackout after a solar storm?

Like the “big one” earthquake expected to hit California sometime in the future, a solar event so large it could wipe out the internet for an extended time is an inevitability, but still an unlikely one right now, Leonard said.

“It could happen tomorrow or it could be another 200 years,” he said, adding that it’s nearly impossible to predict with certainty.

Some experts believe that based on the sun’s cycles of activity, there’s about a 1% chance a year that a Carrington Event-like storm will happen. 

According to a 2021 study published by Sangeetha Abdu Jyothi, a computer science expert at the University of California at Irvine, there’s a 1.6% to 12% chance that it could happen within the next decade. 

George Mason University astronomy professor Peter Becker narrows the time frame.

“The internet was simply not designed to handle this level of communication interference, and, consequently, is considered a very ‘soft’ type of infrastructure,” Becker said in a university news release last year. “Hence, the period from 2024 to 2028 is a time when the entire internet could conceivably be knocked out for a period of weeks to months in the event of a really extreme solar flare.”

There hasn’t been a large solar storm event in the past couple of decades to test our relatively new internet infrastructure while it has increasingly dominated everyday necessities that range from treating patients in hospitals to paying for groceries at a supermarket.

“Most infrastructure is held together by duct tape and chewing gum at the end of the day,” Leonard said.

Can we prepare for this?

The good news is that any major solar activity that could direct a coronal mass ejection toward Earth would be detectable with some lead time. It could take up to a few days for the charged particles to make their way to Earth’s surface, Leonard said.

During that time, emergency officials could start to prepare the power grid. It’s kind of like what Leonard’s mother used to do when a large thunderstorm that could cause power surges was approaching, he said – she would go around the house unplugging things.

“If we had warning that a huge event was coming our way, you'd effectively see the power grid kind of do what my mom was doing very locally in our house, and that is, you could basically take the power grid offline and save the transformers and save the damage,” Leonard said.

DAY OF CHAOS:How CrowdStrike outage disrupted 911 dispatches, hospitals, flights

The preparation may plunge people into rolling blackouts, so Leonard said it’s wise to always think about what you would do in an extended time without power.

We now have satellites orbiting the sun that constantly monitor activity that could impact Earth, he said.

“We're pretty good at knowing when something big has happened on the sun," Leonard said.

Contributing: Eric Legatta