The cyber-security researcher was on a plane, about 20 minutes from its destination, Amsterdam, when it started. Fear gripped her. She knew immediately that something was wrong with her pacemaker, the small medical device implanted in her chest that used electrical impulses to steady her heartbeat.
Could one of the wires that connected the pacemaker to her heart have got damaged? Or come loose? Moe alerted the cabin crew, who at once arranged for an ambulance to be ready and waiting for her at the airport. Had the plane been any further from Amsterdam, the pilot would have made an emergency landing at another airport, she was told.
When Moe arrived at a nearby hospital, doctors pored over her. A pacemaker technician soon found the problem. It was the gadget's tiny computer. Data stored inside the pacemaker's computer, so crucial to its functioning, had somehow got corrupted.And for Moe, the prime suspect that she says most likely sparked this unsettling episode was a cosmic ray from outer space: a chain of subatomic particles slamming into one another in the Earth's atmosphere, like balls colliding on a snooker table, with one eventually careering into her pacemaker's built-in computer mid-flight.
The theory is that, upon impact, it caused an electrical imbalance that altered the computer's memory – and ultimately changed her understanding of the life-saving technology inside her forever.
When computers go wrong, we tend to assume it's just some software hiccup, a bit of bad programming. But ionising radiation, including rays of protons blasted towards us by the sun, can also be the cause. These incidents, called single-event upsets, are rare and it can be impossible to be sure that cosmic rays were involved in a specific malfunction because they leave no trace behind them.
And yet they have been singled out as the possible culprits behind numerous extraordinary cases of computer failure. From a vote-counting machine that added thousands of non-existent votes to a candidate's tally, to a commercial airliner that suddenly dropped hundreds of feet mid-flight, injuring dozens of passengers.
As human society only becomes more dependent on digital technology, it's worth asking how big a risk cosmic rays pose to our way of life. Not least because, with the continuing miniaturisation of microchip technology, the charge required to corrupt data is getting smaller all the time, meaning it is actually getting easier for cosmic rays to have this effect.
Plus, since giant ejections from the sun can sometimes send huge waves of particles towards Earth, what's called space weather, an unnerving prospect looms: we could see much more disruption to computers than we're used to during a massive geomagnetic storm in the future.
Moe's frightening experience with her pacemaker happened in 2016. Once she was discharged from hospital, she received a detailed report from her pacemaker's manufacturer about what had happened. "That's where I learned about the bit flips," recalls Moe, who is now a senior consultant at cyber-security firm Mandiant.
Inside the pacemaker's computer memory, data is stored in the form of bits – often referred to as "ones and zeroes". But the report explained that some of these bits had reversed, or flipped, altering the data and causing a software error. Think of it like pressing the wrong end of the rocker in a long row of light switches. A part of the room will stay dark.
In this case, the error prompted the pacemaker to go into "backup programme mode", says Moe, and it began pacing her heart at a default 70 beats per minute with a heightened impulse. "That's what caused the very uncomfortable twitching," she explains.
In order to fix it, the pacemaker technician had to reset the device to factory settings in the hospital and these were later reconfigured appropriately to suit Moe's heart. But the report offered no definitive conclusions as to why those pivotal bits had flipped in the first place. One possibility mentioned, however, was cosmic radiation. "It's hard to be 100% sure," says Moe. "I don't have any other explanation to offer you."
hat such a thing can happen has been understood since at least the 1970s, when researchers showed that radiation from outer space could affect the satellite. This radiation can take various forms and originate from a number of different sources, both inside and outside our Solar System. But here's what one scenario might look like: protons blasted towards Earth by the Sun smash into atoms in our atmosphere, releasing neutrons from the nuclei of those atoms. These high energy neutrons don't have a charge but they can go on to smash into other particles, triggering secondary radiation that does have a charge. Because bits in computer memory devices are sometimes stored as a tiny electrical charge, that secondary radiation now flying around can upend the bits, flipping them from one state to another, which changes the data.
Edited by Ragul Senthil https://www.linkedin.com/in/ragulms/