<strong>Background:</strong> Type 2 diabetes (T2D) is one of the most common noncommunicable diseases, requiring ongoing lifestyle changes and continuous glucose management through medication, diet, and physical activity. Traditional self-monitoring of blood glucose can be burdensome, especially with frequent finger pricks. As continuous glucose monitoring (CGM) becomes more affordable and accessible, it offers benefits such as increased glucose awareness, behavioral modifications, and reduced anxiety. However, challenges remain, including cost, discomfort, skin reactions, and privacy concerns. In the United Kingdom, perceptions of CGM among people with T2D, including both users and nonusers, are not well understood, limiting insight into factors influencing adoption and sustained use. <strong>Objective:</strong> This study aims to explore how adults with T2D perceive the benefits and challenges of using CGM, including both current users and nonusers. <strong>Methods:</strong> This study used a cross-sectional, online survey using YouGov’s nationally representative panel to explore experiences of CGM among adults with T2D in the United Kingdom. A total of 531 participants were recruited from November to December 2024. Thematic analysis of responses to 2 open-ended questions identified key perceived benefits and challenges associated with CGM use. <strong>Results:</strong> A total of 531 adults with T2D completed the YouGov online survey. Over half were male (297/531, 55.9%) and aged 65 years and older (281/531, 52.9%). Two-thirds (347/531, 65.3%) had lived with T2D for more than 5 years, and 9.6% (51/531) use or had previously used a CGM. Overall, 50.8% (270/531) responded to at least one free-text question, with 49% (260/531) commenting on benefits and 33.1% (176/531) on challenges. Thematic analysis identified five key benefit themes: (1) reduced monitoring burden, described as eliminating frequent finger prick testing and simplifying daily routines; (2) lifestyle feedback, enabling participants to better understand how diet and physical activity influence glucose levels; (3) greater control, by supporting more informed decision-making and increasing confidence in self-management; (4) feeling safer, through alerts for hypo- and hyperglycemia; and (5) sharing data with clinicians, which facilitated communication and more collaborative care. The main challenges were (1) access barriers, including restrictive eligibility criteria and the high cost of self-funding; (2) device issues, such as discomfort, inconvenience, and practical difficulties wearing the sensor; (3) technology reliance, with concerns about depending on devices rather than listening to bodily cues; (4) emotional strain, including anxiety, over-monitoring, and increased preoccupation with glucose levels; and (5) data concerns, particularly regarding accuracy, interpretation, and privacy. <strong>Conclusions:</strong> Adults with T2D, including both users and nonusers, described CGM as a practical and empowering tool that improves understanding, safety, and collaboration with health care providers. Nevertheless, access barriers, usability issues, and emotional and data-related burdens remain major obstacles to equitable adoption. Addressing these through improved affordability, digital literacy support, and customized clinical guidance may support ongoing and inclusive CGM use in routine care.
Background: Various forms of electrical stimulation have been integrated into the multimodal management of spasticity. However, high-frequency electrical stimulation can potentially induce muscle fatigue. The Exopulse Mollii Suit (EMS) is a multichannel full-body garment that delivers low-frequency (20 Hz), low-amplitude (20 V), subthreshold sensory stimulation aimed at reducing spasticity. Objective: Primarily, we examined the effects of a single session of the EMS on spasticity in 7 participants with chronic stroke or cervical spinal cord injury (SCI), specifically those with upper or lower limb spasticity impacting function and gait who were able to walk with minimal or no assistance (Functional Ambulatory Category scores of 2‐5). We assessed the impact on gait and ambulatory function, as well as user perceptions of usability and acceptability. Methods: Participants wore the EMS for 60 minutes, consisting of 30 minutes of standardized goal-directed activities performed in two 15-minute blocks, interspersed with 15-minute rest breaks. Measurements included the Modified Tardieu Scale with surface electromyography for spasticity and functional mobility tests (Functional Ambulatory Category, 10-meter walk test, 5 times sit-to-stand test, and step test). Spatiotemporal gait parameters were quantified using a markerless vision-based motion capture system using the OpenPose BODY25 pose estimation model. Results: On the basis of the Modified Tardieu Scale and surface electromyography signals, improvements in spasticity were only observed in 2 participants. However, 4 participants demonstrated faster walking speeds. Improvements in the 5 times sit-to-stand test and step test were noted in 3 and 4 participants, respectively. Spatiotemporal gait parameters revealed improvements in gait symmetry in 6 participants. Qualitative feedback based on the Assistive Technology Usability Questionnaire for People With Neurological Diseases (NATU Quest) returned positive results in 3 participants. Overall outcomes, defined as meeting the individualized goals of each participant, were positive in 4 participants. Conclusions: This case series provides preliminary evidence that a single session with the EMS may offer benefits for functional mobility and gait quality for individuals with spasticity resulting from stroke or SCI. To our knowledge, this is the first report examining the effects of the EMS in participants with SCI and the first to include spatiotemporal gait parameters associated with its use. However, the small sample size, variable outcomes, and lack of a control group necessitate caution in interpreting these findings and preclude definitive conclusions regarding the efficacy of the EMS. Larger, controlled trials with repeated sessions of EMS use are required to establish the effectiveness and optimal application of the EMS for spasticity management.
<img src="https://jmir-production.s3.us-east-2.amazonaws.com/thumbs/be396b1bb6faa61e07efb5c94224db5d" />
The Food and Drug Administration quietly told wearable maker Whoop last week that it would not take further enforcement action over a controversial feature that gives users a reading of their blood pressure.
In July 2025, the agency warned Whoop for releasing its Blood Pressure Insights feature without clearance, saying it was a medical device that required review. “The product is intended to provide a measurement or estimation of a user’s blood pressure, which is inherently associated with the diagnosis of hypo- and hypertension,” the agency wrote.
Whoop argued at the time that the feature could be released without review because it was intended for wellness purposes and not to diagnose or treat a disease. “We won’t let regulatory overreach dictate how people access their own health data,” CEO Will Ahmed wrote at the time.
Here’s a problem you probably didn’t solve in school: You’re an ambitious young plumber from Brooklyn in a world inhabited by violent human-size mushrooms called Goombas. The love of your life has been kidnapped, so you embark on a quest to rescue her, venturing through stretches of pipe-filled and monster-ridden terrain where your only means of protection are your powers of jumping and stomping.
It’s a journey so arduous that no computer—real or hypothetical—is powerful enough to figure out if you can reach her. And according to research published by the MIT Hardness Group, determining whether your quest is possible at all is at least as complicated as decoding the encryption behind financial transactions. But if this problem could talk, the first thing it would say is “Hello, it’s a-me, Mario!”
For the love of the game
Though it does have a YouTube channel, the MIT Hardness Group isn’t an official research group. Instead, it’s a placeholder name for theoretical computer science projects—including several related to Super Mario—from Erik Demaine’s class Algorithmic Lower Bounds: Fun with Hardness Proofs.
Demaine, a professor of computer science, received a MacArthur fellowship (also known as a “genius” grant) for his work in computational geometry on protein folding and origami. But he also researches complexity theory, which focuses on organizing problems into categories based on how much time and memory space it takes for computers to solve them.
He happens to be an avid Super Mario fan as well. “I grew up playing NES [Nintendo Entertainment System] games,” Demaine says. “I poured many hours into playing as a kid, so it’s fun to come back to it these many years later and tie it into my research.”
Erik Demaine researches complexity theory, which examines the amount of time and memory that computers need to solve problems. He’s also an avid Super Mario fan.
DONNA COVENEY/MIT
Super Mario takes place on a horizontally scrolling universe of platforms, pipes, and other obstacles. The object of the game is to rescue Princess Peach, the monarch of the Mushroom Kingdom, by racing through this terrain while sidestepping or dueling monsters like Goombas and deadly porcupines called Spinies. The game takes place over several levels; in the original version, each level ends with a flagpole that sends Mario on to the next part of his mission.
Over the last 14 years, Demaine and his collaborators have proved many things about Super Mario, such as that it’s even harder than the infamous traveling-salesman problem (which seeks the most efficient route between many different locations) or the problem of factoring large numbers. But the result that surprised Demaine the most came from four of his students: Hayashi Ani ’21, MEng ’23; Holden Hall ’26; Ricardo Ruiz ’24, MEng ’25; and Naveen Venkat ’23, MEng ’24. For their final project in that 2023 class, the team used a combination of fan-made Super Mario level editors and a platform called Super Mario Maker to create levels so hard that they are undecidable. In other words, it’s impossible to write a computer program that always correctly predicts whether, in those levels, Mario can reach the castle.
Previously, Demaine had believed that Super Mario belonged in the PSPACE complexity class, which contains problems that are solvable but whose solutions become impractically complex as the problem gets bigger. At the time, he had even said that PSPACE was Mario’s “permanent home.” But the new findings pushed Super Mariointo RE-Complete, the class of undecidable problems. “It’s the hardest complexity class we could imagine for these sorts of games,” Demaine says.
What computers can’t solve
In 1936, Alan Turing, the father of modern computer science,created a puzzle now known as the Halting Problem to prove it’s not possible to construct a computer that can solve everything.
At the core of the Halting Problem lies a paradox, and it goes like this: Suppose you have a fancy computer, called the Oracle, that looks at any program and correctly determines whether a computer following it will ever come to a stop. For example, if it sees the program “Take 1 and add 3,” the Oracle will say the program halts, but if the program says “Take 1 and add 1 to it until it becomes 0,” the Oracle will say it runs forever.
Now suppose you have another computer, the Contrarian, and you put the Oracle inside it. When you give the Contrarian a program, it passes it to the Oracle and then does the opposite of whatever the Oracle says the program will do. So if the Oracle assesses the Contrarian’s program and thinks it will halt, the Contrarian will run forever. If the Oracle thinks the program will run forever, the Contrarian will halt. Either way, the Oracle’s assessment is wrong, so the classification problem is undecidable.
The proofs that Super Mario is undecidable rely on a more complex version of this idea. The team’s argument breaks down the video game using a technique called a reduction, in which mathematicians convert a problem they’re trying to solve into a problem they already know something about. “The classic example I remember in a math class is: How do you make a pot of boiling water?” Demaine recalls. “Well, I fill up the pot with water from the sink, and then I put it on the stove, and then it eventually boils. Okay, now I’ll give you a pot of water that’s already filled. How do you make a pot of boiling water? Well, I empty out the pot first and reduce to the previous problem.”
In their particular world of platforms and porcupines, the team broke down their Super Mariolevel into localized parts of Mario’s path called gadgets, which they could use to prove that the level was undecidable.
“A gadget in our sense is anything in your environment that decides whether or not you can go through one pattern [within a level],” explains Jayson Lynch ’12, MEng ’15, PhD ’20, a CSAIL research scientist and head of algorithms at MIT FutureTech. For example, in one gadget Mario might need to jump on a platform to avoid a monster as he makes his way across the screen. As a PhD student mentored by Demaine, Lynch spearheaded the formalization of gadget theory and worked on some of the earlier Super Mario papers but did not study the game’s undecidability.
One of Lynch’s favorite Super Mario gadgets is the door gadget, which works like a door that Mario can open, traverse, and close. The door in question is always either open (when the Spiny is on the right) or closed (when the Spiny is on the left). So if a Spiny is pacing back and forth on the left of the door, Mario has to navigate beneath the moving Spiny and jump up to hit a brick block just as the Spiny reaches it. This bumps the Spiny to the right side, which opens the door and allows Mario to travel across the traverse path and get to the spot where he can close the door. Once there, he must time another jump beneath the pacing Spiny to send it back to the left side of the gadget, closing the door behind him.
Mario opens the door by bumping the Spiny from the left to the right.With the Spiny out of the way, Mario can go through the open door and follow the traverse path to the other side. Once there, he’ll be able to bump the Spiny back to the left and close the door.
Since a door is always open or closed, its state can be used to simulate a true or false statement, with open being true and closed being false. Earlier Super Mario papers had strung together multiple door gadgets to simulate a true-or-false problem that complexity researchers already knew to be hard. But to show undecidability, the team used Super Mario level editors to put together another device, called a counter gadget, that tallies the game’s monsters and obstacles.
If you can build a machine with even just a few of those counters, Demaine says, you can simulate an arbitrary computer—one that could essentially do anything a non-quantum computer could do, given enough time and memory. And with no limit on the number of monsters, such a machine could have infinitely expandable memory, even though the level size stays the same, which he calls “pretty wild.” In other words, any theoretical computer can be built in a Super Mario level. “You could use it to solve anything you can use a computer to do,” says Demaine. “You could have it do your taxes, or compile your code, or run an LLM, or optimize your class schedule.” You might even build Super Mario levels that could excel at sudoku, construct optimal chess strategies, or prove any provable mathematical theorem.
The MIT mathematician Marvin Minsky invented counter machines in 1961 to figure out how simple a computer could be while still being “universal” (as powerful as any other computer, given enough time). These theoretical computers each store two numbers and can change them by adding 1, subtracting 1, or doing something special if a number hits a set value.
In the counter gadgets the students designed for Super Mario, the numbers reflect how many Goombas the levels contain. A number increases when a pipe spits out a Goomba and decreases when Mario stomps on one. Mario dies if he collides with a Goomba without stomping on it, so he can continue along the path only when the counter is at 0.
The MIT Hardness group designed this counter gadget in Super Mario Maker 1 to prove undecidability.
Minsky had already proved that counter machines are undecidable because they can run undecidable problems. Since the researchers proved that counter gadgets simulate counter machines, then any level of Super Mario containing a counter gadget will also be unsolvable. “In the future, if someone wants to show a game is undecidable,” explains Holden Hall, one of the students behind the project, “they just have to make one of these gadgets.”
The existence of undecidable problems like the Halting Problem implies that it’s possible to construct an undecidable Super Mario level. Just as the singular undecidable program for the Halting Problem meant thatit’s impossible to figure out if a computer program will run forever, the team’s undecidable level means that it is impossible to determine whether an arbitrary Mario level can be beaten.
Putting the “super” in Super Mario
More than two years after Demaine’s class on hardness proofs, some of his students continue to meet weekly to discuss their Super Marioresearch.
“From the point of view of complexity theory, studying video games is interesting mostly for didactical reasons,” Fabrizio Grandoni, a research professor at the University of Applied Sciences and Arts of Southern Switzerland, told MIT News in 2016. “It’s a simple, natural way to attract students to study this specific topic.”
Hall, who had very little exposure to the ideas of complexity theory before taking Demaine’s class, is a case in point, noting: “I took the class because a bunch of people I knew were taking it. But since I took it, I really enjoyed the class, and so I’ve taken a lot more classes in that realm.”
The applications of the MIT Hardness Group’s work go way beyond stomping on mushrooms and collecting coins. For example, researchers at the University of Texas Rio Grande Valley (including Timothy Gomez, now a PhD student at MIT) have used the gadget theory developed for analyzing games like Super Marioto study the complexity of problems relating to planning robotic motion and modeling chemical reaction networks.
“[Gadget theory] can be used in the negative way to say ‘Oh, well, we should stop searching for algorithms because we know this problem is too hard’—or it can be used in this positive way, because usually, to prove something hard, you’re showing that you can build a computer of a certain type,” Demaine says.
Though there’s no way of knowing what mark Super Mariowill leave on the future of math and computer science, one thing’s for sure: No matter how many princesses he does or doesn’t save, the legacy of this little plumber is set to extend far beyond video screens.
This is today’s edition of The Download, our weekday newsletter that provides a daily dose of what’s going on in the world of technology.
Inside the world’s deepest and longest subsea road tunnel
—Niall Firth
I’m currently around 1,000 feet beneath the North Sea, in a dark, dank cave. It smells weird. And I’m increasingly aware of the pressure from millions of tons of seawater just above my head.
I’m under the iconic fjords of Norway to visit what will soon become the world’s longest and deepest subsea road tunnel—an exceptional engineering feat that will carry drivers deep beneath the North Sea.
I’m here to understand how you make a 16.6-mile highway that sits 1,280 feet below the sea at its deepest point. And also—at a time when it can feel hard to get anything done—to reassure myself that ambitious engineering is still possible. That we can still make things.
This story is from the next edition of our magazine, which is all about engineering. Subscribe now to get a copy when it lands on Wednesday!
Want to get a data center online quickly? Give it some flex.
The AI boom is putting unprecedented pressure on the electric grid. But rather than rushing to build new power plants, companies could find part of the solution right under our noses—or, more precisely, in the transmission lines under our feet and above our heads.
If data centers can limit the power they draw during high-demand stretches, they won’t need to wait for big infrastructure upgrades or build their own off-grid generation.
The idea of flexibility isn’t entirely foreign to grid operators. But a new generation of software could make the process faster, smarter, and more precise for the AI era.
I’ve combed the internet to find you today’s most fun/important/scary/fascinating stories about technology.
1 SK Hynix has overtaken Samsung as South Korea’s most valuable company It’s also now the world’s most valuable memory chipmaker. (Reuters $) + And one of the biggest beneficiaries of the global AI boom. (BBC) + AI’s need for memory chips is set to skyrocket device prices. (WSJ $)
2 Trump says he no longer views Anthropic as a national security threat “Well, not now, but a week ago, maybe,” he told The Axios Show. (Axios) + He praised the response of Anthropic CEO Dario Amodei. (Reuters $) + Anthropic’s IPO outcome could depend on the midterms. (WSJ $) + A culture war tactic against Anthropic has backfired. (MIT Technology Review)
3 SpaceX has received the lowest possible ESG rating Index provider MSCI gave the company a triple C. (Financial Times $) + Russia got the same score after invading Ukraine. (Business Times) + Elon Musk previously called ESG metrics the “Devil Incarnate.” (CNBC)
4 A Tesla on Autopilot allegedly crashed into a Texas home and killed a woman The driver said his Tesla Model 3 was in self-driving mode. (NYT $) + Tesla’s AI trainers don’t trust its self-driving tech. (Reuters $)
5 Polymarket reportedly paid creators to post fake betting videos Clips showed them winning big on bets they would have really lost. (WSJ $) + Polymarket bets on an Iran deal are fueling insider-trading fears. (Bloomberg $)
6 Physicists have proposed that black holes don’t exist They may be something much stranger: “gravastars.” (404 Media) + This is the first ever photo of a black hole. (MIT Technology Review)
7 A daring space rescue mission is set to launch this week A spacecraft will try to lift an observatory into a safer orbit. (Space) + We’re putting more stuff into space than ever. (MIT Technology Review)
8 Nothing’s next budget phone has been cancelled due to “RAMageddon” The company said memory prices pushed costs too high. (The Verge $) + Buying a used phone makes more sense than ever. (Wired $)
9 A viral doomsday scenario aims to pierce Europe’s AI complacency It envisions the US and China tearing Europe into pieces. (Guardian)
10 Scientists have invented a way to brew espresso with ultrasonic waves No hot water required. (Wired $)
Quote of the day
“Even before we start reaping the benefits of AI in our devices, we are already paying the bill.”
—Francisco Jeronimo, an analyst at IDC, tells CNBC that consumers are covering the costs of the ongoing memory shortage.
One More Thing
BRIAN OTIENO
How mobile money supercharged Kenya’s sports betting addiction
As the lorry he’d flagged down lurched through Kenya’s western highlands, Bill Kirwa’s Infinix smartphone dinged with a notification. The bet of 3,500 shillings he’d placed with mobile money—then worth approximately $35—had just turned into nearly $8,500.
Kirwa, now 26, put the windfall to good use, purchasing a car that enabled him to drive for Wasili, an Uber-style ride-hailing service. But he continued gambling, and over time, his losses mounted. In just a few years, he’s effectively erased his big win.
Kirwa’s experience is hardly unique. Across Africa, the rapid spread of smartphones and mobile money has fueled an explosion in online gambling. But nowhere is the craze as acute as it is in Kenya. Find out why.
—Jonathan W. Rosen
We can still have nice things
A place for comfort, fun, and distraction to brighten up your day. (Got any ideas? Drop me a line.)
+ A clever Bengal cat has seemingly learned to understand English—and talk back. + This list of the 100 greatest bird names lovingly captures the quirks of avian taxonomy. + Darth Vader’s weird chestplate transforms into a cassette player in these reworked Star Wars clips. + Trace the history and evolution of heavy metal music through the interactive genres and playlists of Map of Metal.
It’s cold, it’s very, very noisy, and—if I can be quite honest with you—I’m not feeling super relaxed.
I’m currently around 300 meters, or 1,000 feet, beneath the North Sea, in a dark, dank cave. It smells weird. And I am increasingly aware of the pressure from millions of tons of seawater just above my head, pushing down with a force of more than 500 pounds per square inch. Picture a baby rhino standing on a postage stamp.
Only fabulous engineering is keeping me from being crushed, drowned, disappeared. My safety goggles are foggy.
Just a few hundred meters away, someone is about to blow up a giant rock wall. Luckily, earlier that day I was given a full safety briefing, and I’ve got a special hard hat on. “Don’t worry—if you don’t make it, we’ll have your stuff sent back to your office,” geologist Anne-Merete Gilje tells me, straight-faced. Ah, Norwegian humor.
“It’s kind of a lifestyle. You have to be a little bit crazy to work underground all the time.”
Niclas Brusehed, tunnel foreman, Implenia
I’m in this odd situation under the iconic fjords of Norway to visit what will soon become the world’s longest and deepest subsea road tunnel, called Rogfast (short for “Rogaland Fixed Link”). I want to understand how you make something as audacious as a 26.7-kilometer (16.6-mile) highway that sits 390 meters (1,280 feet) below the sea at its deepest point. And also—at a time when it can feel hard to get anything done, especially in the US—to reassure myself that ambitious engineering is still possible. That we can still make things.
The Norwegians already have the world’s longest subsea tunnel, the 14.4-kilometer Ryfylke, though Rogfast will dwarf it. Their expertise has attracted attention from Japan, Spain, Morocco, and even a number of US states, whose representatives were due to visit the site in May, just weeks after I went. They, too, want to know how Norway does it.
The answer: tons of explosives.
The entire endeavor feels like an obstinate refusal to give in to physics and geology. “It’s always exciting,” Niclas Brusehed, a tunnel foreman at Implenia, a Swiss firm involved in the project, tells me. “Every blast creates a new world.” There’s not just the blasting of the tunnel itself—although that is an epic project on its own—but an immense logistics challenge involving huge ventilation shafts, extreme pressure, underground roundabouts, and the complex Norwegian geology. Oh, and the water. So much water.
“This is the longest continuous blast on the sea,” says John Olaf Østerhus, assistant project manager at Implenia. “Never been done before. We can’t buy a book to see how we do this.”
All right, time to fish my phone out of my safety suit—don’t want to forget this.
On another planet
Arriving at the rock face where the tunnel hits seabed feels like being on the moon. It’s a huge slab of stone at the end of a long, dark, wet, wide passageway that’s lit (barely) by electric lights. Giant vehicles carting tons of rocks rumble past periodically, and we pull to the side of the road to let them by.
Rescue chambers are spread throughout the tunnel network.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
Workers clock in for 12-hour shifts, 6 a.m. until 6 p.m., deep in the bowels of the Earth where no natural light can reach. Twelve days on, 16 days off. They eat their lunch at a table in this damp cave surrounded by portacabins plastered with safety notices. “It’s kind of a lifestyle,” says Brusehed, laughing. “You have to be a little bit crazy to work underground all the time.”
These crazy engineers are here to make tunnels the Norwegian way. The nation frequently uses what’s known as the drill-and-blast method instead of the tunnel-boring machines that are more typical elsewhere. This approach offers more flexibility for long, complex operations with varied rock types. Each blast adds about five to six meters to the tunnel.
Rogfast is being built inward from the ends to speed things up. The construction company Skanska is leading from the north, coming from the island of Vestre Bokn; Implenia has joined a company called Stangeland to tunnel from Randaberg in the south, which is where I am. Both teams use multiple laser scans each day to consistently measure their orientation and check that the tunnel is exactly where it should be. The two ends should meet sometime in 2029, with no more than just a few centimeters of deviation.
The caves are like towering cathedrals, scattered with rubble.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
Norway has constructed more than a thousand kilometers of tunnels over the past several decades. The depth and length of these make the best efforts to date of Elon Musk’s Boring Company—a mere 2.7-kilometer tunnel in Las Vegas that is just 3.6 meters wide—look rather pathetic. The country’s spectacular setting makes such builds necessary; while Norwegians are proud of having the second-longest coastline in the world after Canada, getting up and down the west coast requires multiple ferry rides between islands, which can move extra slowly when the weather’s bad.
After it’s completed, which is scheduled to happen in 2033, Rogfast should help eliminate two ferry routes and cut the five-hour journey between the southwestern cities of Stavanger and Bergen by 40 minutes. It will funnel four lanes of traffic deep beneath the fjords of Boknafjord and Kvitsøyfjord, and at one section a relatively scant 50 meters of rock will separate the drivers speeding through the tunnel from the bottom of the North Sea. There are also, delightfully, two undersea roundabouts located 220 meters below sea level.
But the first job is to contend with all that water.
The never-ending battle
Subsea tunneling is defined by a constant, ultimately unwinnable battle with the ocean. The sheer weight of the sea above you, and the crushing pressure, means the water will always find a way in. “It’s the volume and the pressure that’s the biggest risk,” says Ole Magne Rønning, project leader for Implenia/Stangeland.
So before tunnel engineers blow stuff up, they need to check for leaks. Into the rock face ahead of them, they drill a number of narrow holes that go 25 to 30 meters deep to see how much water comes through. Even a small probe can unleash a torrent within seconds, says Rønning. When road traffic eventually rumbles through these tubes, water will still trickle from the rocks; it will be redirected into mini reservoirs dotted throughout the tunnel network before being pumped back out.
Since stopping the water entirely is impossible, the game is instead to push it away as best you can. If the leakage in front of the rock face exceeds a certain limit—around four liters per hole per minute—then the next stage is “grouting”: pumping a mixture of cement-like sludge into new holes that fan out in the ceiling above and around the face. Ideally, you address the leaks that are ahead of you; “it’s a lot more difficult to stop a leak that’s behind you,” says Rønning.
At one point deep below the sea, I chat with Tarald Johan Nomeland, the project’s grouting specialist. He’s big and bearded, perhaps one of the most Norwegian-looking men I’ve ever met. He stands, towering above me, and shakes my hand in his giant bear-like paw. Grouting is in Nomeland’s family; his dad did it too. He loves it. “There’s not necessarily just one solution to a problem,” he says, eyes flashing with delight as he describes fighting the interminable battle with the water. “There may be many solutions.”
The amount of grouting needed determines how fast the project can move. On the Skanska side, for example, some weeks the face moves 30 meters; others, as few as 10.
This isn’t made any easier by the rock itself. The seabed around Norway was shaped by glaciers during the Ice Age. As the ice retreated, it dragged softer rock with it, carving out the fjords for which the nation is so famous. But this legacy makes digging subsea tunnels particularly gnarly. Much of what’s left is the hard, difficult-to-break stuff.
And it’s not just one type of rock, either. There are “big wide areas where we don’t know what’s down there,” says Gilje, the geologist who is a project manager for the Norwegian Public Roads Administration, which is in charge of the entire project. Before any construction started, boats took core samples from the seabed along the planned tunnel route. Seismic surveys from the ocean surface—like those that look for oil in the region—helped fill in the gaps.
Each kind of rock presents its own challenges, so the engineers “have different techniques for different problems,” Gilje explains. For example, they found that one southern section contains a lot of phyllite. Phyllite is considered “nice” to work with. It is formed from a combination of shale, siltstone, and mud over time and is pretty compact, with few cracks to let water through. Its compact nature means it requires more explosives per blast, however. It also contains a lot of quartz, which is toxic when released into the air during blasting. So workers wear monitors to measure their exposure, and a curtain of water sprayed in front of the rock face helps prevent too much from drifting into the tunnel.
The northernmost part of the route, meanwhile, is made mostly of solid granite and a similar rock called gneiss. Both are hard but contain fractures that allow the seawater to trickle through.
The rock type can also change over just a short distance. So during the dig, every 80 meters or so, an engineer sends sound waves through the face to expose its secrets and help evaluate its structural integrity. The rock is graded on a scale of 1 to 5, with 5 being the worst and least stable. “When you are reaching class 5, then it’s almost like soil. It’s not rock anymore,” says Rønning.
This investigation informs the kinds of structural supports each section will need—from steel rods that fan out above the rock face like an umbrella, for the strongest rock, to reinforced-concrete arches that hold up the weakest. To seal everything off, the team sprays a substance called “shotcrete,” liquid concrete mixed with reinforced-steel fibers, onto the walls throughout. A plastic membrane and concrete panels are fitted later.
“It’s going to be a very safe tunnel,” Gilje says. “It’s going to last for 100 years.”
Strange dangers
While I may not be brave, at least I don’t get seasick. Back at the surface, I board a small ferry that putters and sloshes its way from the mainland to Kvitsøy, a sparsely populated municipality made up of 365 separate islands and islets—something its 550 or so inhabitants are very proud of, even though most of these islands are uninhabited chunks of rock.
For the next few years, Kvitsøy’s population will experience a tiny boom as its largest island hosts a semipermanent encampment of contractors and engineers working on what is probably the most complex part of the Rogfast project: the giant ventilation shafts that will sit roughly halfway along the tunnel’s length to bring fresh air into the entire network, and remove the stale air in turn.
It’s also one of the reasons why road tunnels are much more complex than rail tunnels. Cars pump out fumes that have to be vented away. During construction, fresh air flows in via huge plastic tubes suspended from the ceiling, but eventually, Rogfast’s air will come in through two nine-meter-wide shafts that will bore down from Kvitsøy’s surface: one to bring it in, one to take it out.
Hundreds of steel rods are fitted to support the ceiling and walls.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
Creating these shafts is a wild process. First, narrow boreholes are drilled from the ground down into the tunnel 210 meters below the surface. A vertical drill rig is then pulled up through the hole from the bottom, widening the shaft to 2.4 meters as it ascends.
Then explosives are set off on the island’s surface, bashing down through the rock to widen the shaft. A large digger pushes the resulting debris down the narrower, not-yet-exploded length of shaft below, sending rocks barreling toward the tunnel at the bottom like socks tumbling down a laundry chute. Trucks haul away the fallen rocks. This process happens in stages, repeating at regular intervals, opening up the passage a bit deeper with each pass. Once it’s all done, steel rods are installed in the shaft’s walls to keep it secure.
Down below, I stand beneath one of the narrow guide holes for one of the two ventilation shafts. The ceiling soars overhead—a strangely beautiful cathedral, cragged and shadowed by lamplight.
Besides poisonous air, the epic nature of these engineering projects throws up other surprising dangers. For example, Rogfast will take about 30 minutes to drive through. It doesn’t seem that long, but the project’s designers worry that the monotonous environment may lull some drivers to sleep.
Engineers faced this problem with Ryfylke—which, as the current longest subsea road tunnel, has been a testing ground for its bigger sibling. It relieves the tedium with a large hall that opens up in the middle of the tunnel, lit by colored lights that change each day. When Rogfast is finished, artists will be invited to do something similar, using lights, colors, and shapes to keep drivers alert.
Then there are the environmental risks. What is there to do with all the loose rock created by the blasts? The engineers predict 8.5 million cubic meters’ worth. That’s enough to fill more than 2,500 Olympic-sized swimming pools. The solution is to bring it back to the surface, where it can be used to create new land. To do this, the project employs a giant barge designed to split open and dump 350 tons of rock in one go.
But adding more rock particles to the water can make it hard for fish to breathe, says Elizabeth Austdal Paulen, Implenia’s environment lead on the project and my fellow passenger on the windy (and soon to be redundant) ferry over to Kvitsøy. Her team monitors their levels in real time: If the particulate count is too high, the drops must pause until the new rock has settled on the seabed. The goal is to protect lobster fishing, a vital part of the local economy, and to safeguard the breeding time for cod, which was an issue when I visited.
Finally, of course, on top of all this are the many hazards for the people who are actually doing all this blasting and digging and hauling. Or, say, for the visitors who are finding their inner nine-year-old getting a little too giddy about what’s next.
Time to blow
Before I’m allowed underground, I must sit through a short safety briefing, where I learn there are multiple hazards when you’re that deep. Fires, for instance, can break out, exacerbated by the way the salt water affects electronics. Just a week earlier, a car caught fire somewhere deep within the network. “You have to be aware all the time,” says Anne Brit Moen, the project lead for Skanska. “It’s a very harsh, harsh climate.”
After the session, I’m given a hi-viz suit, the hard hat (which has built-in ear protectors), gloves, safety glasses, and reinforced boots. I get instructions on how to operate the oxygen mask that will be in the car with me, and a device to put in my pocket that will track my exact location on screens in the control room. The device also acts as a personal warning system: If it vibrates and a blue light appears, then a blast is imminent and I must get to safety; if it vibrates and glows red, umm, well, that’s bad news and it’s time to evacuate.
“If you’re the first to the rescue chamber, press the green button … close the hatch and sit down and be calm.”
Ketil Myklebost, project manager, Implenia
But let’s say I can’t—I’m too deep underground. Then there is a second, less fun option. I’m given instructions on how to access the rescue chambers. These metal boxes—about the size of a large van—can squeeze in around 16 people, and each contains chocolate, water, radio equipment, a defibrillator, and enough oxygen for 24 hours. I see them dotted throughout the tunnels as we drive through. Worst-case scenario, I’m supposed to get to the nearest one, sit tight, and hope to get rescued.
“If you’re the first to the rescue chamber, press the green button for 15 seconds to release pressure,” says Ketil Myklebost, a project manager at Implenia. “And then close the hatch and sit down and be calm.”
Calm, right. Okay.
In the hours before my visit, a huge drilling “jumbo” rig puts as many as 180 holes deep into the rock face. The number, angle, depth, and spacing of the holes is calculated in advance using software but finalized at the face—here, they’re almost six meters deep. At one point, I clamber up into the jumbo and inspect the pattern on its screen, matching it against what I can see on the huge rock face, which stands more than 12 meters tall and wide.
The holes have been stuffed with an explosive slurry. (Someone quips that if I get any on my clothes, I’ll be stopped at the airport as a terrorist. A Norwegian joke, again.) As I watch, workers in a kind of cherry picker fit each hole with a detonator and make sure they’re all connected to one another by wire, ready to be triggered remotely.
Then my personal safety device starts vibrating. When I take it out of my pocket, it’s blinking blue. Showtime.
How far back do I need to be? “It’s dangerous in this direction 500 to 600 meters, but if you’re around the corner you can be closer,” says Sveinung Brude, project manager for the Norwegian Public Roads Administration.
Workers lay asphalt.
COURTESY OF NORWEGIAN PUBLIC ROADS ADMINISTRATION
I stand by the worker who will trigger the blast from what looks like a small briefcase with an antenna. Then he presses the button.
The shock wave hits me before I hear it. My chest vibrates. In the first few milliseconds, a propulsive thump briefly stuns my senses, followed immediately by a rolling, crumpled thunder.
Just a moment later—almost instantly, really—wind billows through the cavern. Rocks clatter as they crash off the walls. I try not to show any panic. (That was meant to sound like that, right?) A hush falls, and there’s just the tinkling of stones as they bounce and skip amid the rubble.
Dust rises into the air, and there is a strange smell.
Through my ear protection it sounds like the end of the world.
Niall gets to grips with what it’s like to work under the sea.
NORWEGIAN PUBLIC ROADS ADMINISTRATION
The explosion itself is a beautiful choreography: Blasts are initiated one after another, starting from the center. In video footage, you can just about hear the sequential pitter-patter of the charges as they go off. (In person, it’s a bit more all-at-once and overwhelming.)
Rogfast has just crept another few meters closer to completion.
I find myself grinning. Maybe there’s something extremely primal about being near an explosion? I’m not sure. I look down at my hand, where I have my phone out, recording the intensity of the moment.
Except … I wasn’t recording. The stupid rubber safety gloves I’m wearing must have stopped the command from going through.
Oh no. Oh no.
A once-in-a-lifetime opportunity, and I, uh, blew it. “I WASN’T RECORDING!” I shriek.
“It’s better that way,” says Rønning, walking off into the gloom. “You’ll remember it.” How very Norwegian.
This is today’s edition of The Download, our weekday newsletter that provides a daily dose of what’s going on in the world of technology.
A startup claims it broke through a bottleneck that’s holding back LLMs
AI startup Subquadratic came out of stealth last month with a huge claim: it had solved a mathematical bottleneck that had held back large language models for almost a decade.
The purported breakthrough comes from slashing the number of computations transformers need to carry out to generate answers. The result is a faster and cheaper LLM that uses far less energy than any other model on the market.
Many experts remained skeptical—but Subquadratic has started to share the receipts. They suggest that their approach might be worth paying attention to.
This week, I covered the story of Casey Harrell—a man with ALS who is “the first power user” of a brain implant. The device has enabled him to maintain an income, reconnect with friends and family, and read to his daughter. He told me that it’s “nothing short of revolutionary.”
Over the past couple of years, the number of BCI trial volunteers has soared. This year, China became the first country to approve a BCI for medical use. Advances in technology are allowing engineers to provide more features than ever. BCI research is properly taking off.
This story is from The Checkup, our weekly newsletter giving you the inside track on all things biotech. Sign up to receive it in your inbox every Thursday.
The must-reads
I’ve combed the internet to find you today’s most fun/important/scary/fascinating stories about technology.
1 Amazon workers who backed data center limits may face termination The engineers say they’re under investigation by the company. (NYT $) + And could face discipline, including potential termination. (The Verge) +They had testified at meetings about pausing data centers. (CNBC) + They’ve filed a joint complaint to Seattle’s Office for Civil Rights. (Wired $)
2 A new fossil discovery has rewritten 150 years of evolutionary theory It suggests early land vertebrates skipped the tadpole stage. (New Scientist $) + And raises questions about how vertebrates adapted to land. (404 Media) + Sponges may have been the first animals. (MIT Technology Review)
3 Bernie Sanders plans to give the public direct ownership of AI firms He’s unveiled new legislation to create an AI sovereign wealth fund. (AP News) + It would be funded through a one-time tax on AI companies’ stock. (Quartz) + And make annual payments directly to Americans. (Washington Post $)
4 Investors in China secretly acquired stakes in SpaceX before its IPO One had ties to Chinese military contractors. (ProPublica) + The US fears China has got one of ASML’s top machines. (Reuters $)
5 Researchers have figured out Russia’s nuclear-powered missile They call it “a terrible idea”—but not an impossible one. (NPR) + NASA is building a nuclear reactor-powered spacecraft. (MIT Technology Review)
6 Longevity medicine faces a do-or-die moment in a landmark trial It will test whether cellular aging can be safely reversed in humans. (Axios) + The next step is “chemical reprogramming.” (MIT Technology Review)
7 Studies suggest AI may already be deskilling professionals Over-reliance appears to weaken doctors’ and engineers’ abilities. (Nature)
8 Tech workers who maxed out their AI use are now trying to minimize it Spiralling costs mean “tokenminning” has replaced “tokenmaxxing.” (NYT $)
9 Scientists say the human genome’s structure may confound AI models Which would constrain AI-based models of biology and disease. (Quanta)
10 A new robotic self-driving toilet brings the bathroom to you The Xiaoban also cleans up and empties itself all on its own. (The Verge)
Quote of the day
“They hated me. They were doing everything they could to knock me down. And look at them now.”
—Donald Trump mocks Mark Zuckerberg and Jeff Bezos in a conversation with Elon Musk that’s recounted in a new book, Wired reports.
One More Thing
PABLO DELCAN
Technology can help us feed the world, if we look beyond profit
The pandemic exposed the weak spots in our interconnected food system. They’re the result of decades’ worth of technological advances, from globe-spanning shipping to refrigeration networks. But technology is not inherently opposed to sustainable and resilient food systems.
Powerful technologies like genetic modification can create stronger local agriculture and a healthier food system—but they normally aren’t. The challenge is ensuring they serve food security and human well-being, rather than simply maximizing profits.
Junkosha has named two medical device developers as Technology Innovator of the Year Award winners. Anchor Balloon Inc. founder and CEO Dr. Vishal Gupta won the $25,000 late phase award for the AngioLock coronary balloon catheter, described as a “zip-line catheter designed to stabilize and simplify precise stent delivery in complex coronary anatomy.” Junkosha also…
