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. Why “reprogramming” is the buzziest approach to reversing aging right now Earlier this week, Life Biosciences, a biotech company focused on reversing age-related diseases, announced that it had dosed its first volunteer. A person with glaucoma has had an experimental treatment injected straight into their eyeball. The idea is to treat the disease by regenerating healthy nerves in the eye—but the company already hopes to go further. If the treatment can reverse glaucoma, similar treatments could reverse other diseases of aging. Maybe, just maybe, they could reverse aging altogether. The approach relies on “reprogramming” cells to a younger state. It’s one of many strategies being explored by biotech companies looking to slow and reverse aging. But of all of them, it seems to be the one that is truly taking off.
Read the full story on the pursuit of reprogramming for rejuvenation. —Jessica Hamzelou
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. Inside Interoception: The hidden sense of how you feel inside Scientists have a word for how we sense ourselves from the inside: interoception. Today, thanks to a 2021 Nobel Prize and new tools that can map internal signaling across the body, research into interoception is taking off. As researchers decode how signals move between body and brain, a clearer picture is starting to take shape—with implications for how we understand and treat conditions from obesity to chronic pain to anxiety. Find out how it’s leading to a “new continent of awareness.” —Katherine W. Isaacs This story is part of MIT Technology Review Explains, our series untangling the complex, messy world of technology to help you understand what’s coming next. You can read more from the series here.  The must-reads I’ve combed the internet to find you today’s most fun/important/scary/fascinating stories about technology.

1 SpaceX has officially delivered the largest IPO in historyIt’s raised a record $75 billion at a $1.77 trillion valuation. (Axios)+ Making Elon Musk the world’s first trillionaire (on paper). (Reuters $)+ The IPO will now put his “extreme ownership” to the test. (Wired $)+ While China attempts to build a Starlink rival. (Rest of World)+ And other challenges to SpaceX emerge. (MIT Technology Review) 2 Jeff Bezos wants to build an “artificial general engineer”Through his new industrial AI startup, Prometheus. (NYT $)+ Which just raised $12 billion, valuing it at $41 billion. (TechCrunch)+ Meanwhile, OpenAI is building a fully automated researcher. (MIT Technology Review) 3 Chinese regulators are dramatically intensifying tech enforcementA spell of relative restraint has ended. (SCMP)+ Regulators have admonished e-commerce giants Alibaba and JD.com. (FT $)+ And blocked Meta’s acquisition of Chinese AI startup Manus. (BBC) 4 Google says Chinese cybercriminals used Gemini to scam AmericansIt’s suing the network over the alleged AI-powered scams.(NYT $)+ “Supercharged scams” are one of our 10 Things That Matter in AI Right Now. (MIT Technology Review) 5 Ukraine’s defense AI chief predicts a “new paradigm” of warfareHe expects AI systems to unify into a single battlefield network. (Reuters $)+ AI chatbots could be used for targeting decisions. (MIT Technology Review) 6 Anthropic has rankled users with its safety-first Fable modelStringent safety rules and refusals to help have sparked a backlash. (NBC)+ Anthropic has backtracked on some policies. (Wired $) 7 Pokémon Go data trained AI that could assist military dronesIt could help them locate themselves in war zones. (Guardian)+ Pokémon Go data is also training delivery robots. (MIT Technology Review) 8 Orbital data centers are harder than Silicon Valley thinksShedding heat in space requires ingenious new designs. (IEEE Spectrum)+ We need a few things to put data centers in space. (MIT Technology Review)
9 A toy universe shows time could be a quantum illusionIt could emerge from quantum interactions, rather than just existing by default. (New Scientist $) 10 Chatbots keep telling stories about a lighthouse keeper called EllaAnd now we may finally know why. (404 Media)
Quote of the day “People are paying a trillion dollars for Elon.”  —Ross Gerber, the CEO of Gerber Kawasaki, which owns SpaceX stock, tells the New York Times why he believes the company’s IPO is overvalued. One More Thing GEORGE WYLESOL How generative AI could reinvent what it means to play I was immediately attracted to open-world games, in which you’re free to explore a vast simulated world and choose what challenges to accept. To make them feel alive, these games are inhabited by crowds of “nonplayer characters” (NPCs). But the illusion starts to weaken when you spend enough time with them. It may not always be like that. Just as it’s upending other industries, generative AI is opening the door to entirely new kinds of in-game interactions that are open-ended, creative, and unexpected. The game may not always have to end. Discover how generative AI could make games—and other worlds—deeply immersive.
—Niall Firth 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.) + My feet have fallen for the Crocs x Super Mario collection.+ Denmark’s 2026 Mullet Championship is the hottest hairdo contest of the year.+ Hungry at half-time? Here are seven mouth-watering international recipes inspired by the World Cup.+ Feast your eyes on a helicopter bound for Mars and a flowery Milky Way frame in Nature’s top images from last month.

There we were, a regular murderers’ row of librarians. Little Jo. Eustace. And me. Turning around in the nave of our library to greet the sound of footsteps, pistols leveled in case whoever was coming in didn’t respect sanctuary. Little Jo had a stack of books under one arm. Eustace was holding the screwdriver she’d been using to tune the aneroid barometer. Eustace had painted height lines on the big double doorframe, as only half a joke. When the wanderer paused, outlined within, the eiroscope and I both registered that they were exactly five feet, ten inches. With their Cool Hand Luke hat on.  They paused, boots scattering sand on the threshold. A narrow straight-hipped silhouette against the white noon light falling from the white, white sky. The doors had been open to catch a breath of wind, but there wasn’t any. So when the stranger swayed, it wasn’t from the gale.  “Sanctuary,” they croaked, and remeasured their length onto the rug between the smoothed trunks that held the loft up. The Stetson went rolling. Little Jo dropped her stack of books and her pistol and dashed forward. I jumped at the noise but holstered my own shooter in case I came to need it. We each grabbed an armpit and dragged the outlaw’s feet inside the threshold, grunting, lickety-split. I slipped their floppy pack off, empty metal water bottles clanking as I set it aside. Eustace helped us roll them, and I laid the soft of my wrist on their head.
Hot as Hades, but still tacky. Moist enough that my skin gave a reluctant pop when I lifted my arm. Not past saving.  “Let’s get them someplace cool,” I said. “Little Jo, go empty out the ice machine.”
Eustace and I toted our fugitive down to the cellar, using the rug as a stretcher. It was Diné, vermilion with black and gray, and I was glad they hadn’t thrown up on it. Though that wool had seen worse. Mehitabel, the black cat, watched us from atop the timber lintel of the cellar access. Her tail tip flicked incuriously. She was on pack rat watch. Aloof from human antics. The cellar was narrow, low, and stocked with Eustace’s blue corn lager in bottles, prickly pear jam, potatoes, and the few hard-rind squash still left over. The mud walls were whitewashed, and while it wasn’t quite cool, it was better than the outside. We stripped off the stranger’s clothes, trying to slit along the seams so we could repair them later. City stuff, mass-produced and machine-woven. Little Jo brought the ice and went back upstairs to watch alongside the eiroscope in case pursuit was close behind. The stranger’s eyes flew open, and they screamed when I packed wet cold pillowcases against their pink bits. Eustace had to hold their battling hands away from their genitals until they settled.  Those were good signs. Brown eyes blinked between heavy creases. “What the hell—”
“I’m Ponyboy,” I told them. “She. PhD. I’m one of the librarians here. This is Eustace. She, MLS.” They struggled to sit upright. “Shhh.” Eustace pushed them down and laid an ice-soaked cloth across their eyes. “You’re heat-sick.” “Sanctuary,” they whispered. “Did I say?”
“You did. This is the Bōchord. You made it. Must have been a long walk.”  We continued packing ice around them—into their armpits now. They yelped and moaned but gave up fighting. “What’s your name?” “Guh—” Too long a pause to be believable. “Gibson. She.” 
“Welcome to Judgement, Gibson,” I said. “Sorry about the cold, but it’s got to stay there for a little.” “My pack,” she said, shrilling. “My pack. I need it.” “It’s safe,” Eustace told her. “You just relax and we’ll get it for you.” When I came back out the nave was still and heavy in the heat, as if nothing had happened. Little Jo had turned one of the bumpy-backed wooden chairs to face the door and was sitting on it, hands buried in tiered skirt ruffles between her knees.  I looked left, two steps up into the sanctuary, but all was calm, the work I’d left—cataloguing—still heaped on the blond wood altar table. Behind it, bright primitive saints in shades of blue-green, scarlet, and yellow looked with shocked eyebrows down from the adobe wall.  I moved up behind Little Jo, making sure she could hear me coming. My footsteps echoed from roof joists made from entire peeled and waxed trees. Scrolled headers painted the color of good turquoise held them over the bookcases lining each long wall. 
The Bōchord. Book Sanctuary. Nuestra Biblioteca del Perpetuo Socorro.  Population until this morning: three.
“Any sign of trouble?” Little Jo turned her unambiguous jaw away, tendons rising on a long neck, jailhouse ink black-blue on her red-black skin. A sweaty curl escaped down her nape. My fingers itched to tidy it. But it hurt too much to even think about taking a risk that profound. She stretched horny discalced feet before her. Cracking calluses wrapped the balls and heels. “Only what we brung in with us.” She was a double murderer, but I couldn’t tell her I knew how she felt, because I hadn’t heard about her history from her. And her guilt wasn’t mine to absolve. You do your own time. Not anybody else’s.  “You check her bag for anything dangerous?” “She’s got an SSD.” Little Jo shrugged. “No threat if we don’t plug it into anything.” “The eiroscope got anything to say?”
“I can speak for myself, Ponyboy,” said the eiroscope from the air all around. Actually it used the old wireless speakers tucked in the corners, but the effect was as of a choir of angels. Or an airport announcement you could actually understand. “I’ve been focused on the CubeSat launch.” I startled. “Shit. What time is it?” “Eleven forty-seven. The launch came off perfectly. Our last batch of sats are on their way.” Little Jo breathed deep and unfisted her hands from her skirts. There were so many hours of work in those satellites, and so much of the money we collectively squirreled away as researchers for hire had gone through cutouts and shell companies to pay for the launch. The parts—boards, housings, chips—were salvaged from the same derelict data center where we got our solar panels and the hardware the eiroscope ran on.  We were behind schedule, because we’d lost one payload when the commercial rocket we’d rented cargo room on exploded. But this would be our last batch, if they reached orbit safely. I turned my wrist to glance at my watch even though I already knew what time it was. The second hand ticked past the big hand. Old school.  The rainbow band was a tiny rebellion, though out here it didn’t matter. Nobody was going to send me back to jail for subversive iconography. Unless I left our little patch of exile. Ten minutes and we’d know. Ten minutes and stage three of our plan—assembly—could commence. It was out of my hands, and anyway the eiroscope would tell us if the telemetry wobbled. She was a ghost astride the radio signals to and from ground control. It had taken a lot of engineering to get us this far. Engineering, software and relational. Computer. Social and mechanical. I walked beside the bookcases, running my hand along the shelves, over the UDC labels. Some shelves even held books, though none of mine were there. But the majority of the information we protected like Irish monks from this willful dark age was digital. Those monks had also been librarians. I knew my fidgeting annoyed Little Jo but I couldn’t stop. I was killing time. When I had murdered enough of it, the eiroscope said, “Payload away. Everything seems nominal. I have contact with the CubeSats.” “All of them?” “Twenty out of twenty,” the eiroscope said. “A triumph of modular design.” “Sure,” said Little Jo. “As long as we can get them to assemble. And the solar panels and sails deploy.” “And, and, and,” I teased.  She flipped me off with a gnawed green nail. My hand rested on the label marked 326. Social sciences, slavery and unfree labor. I pulled down a solid-state drive full of biographies and case studies of people who had spent time—and sometimes their whole lives—in labor camps or chattelhood. People born into bondage or remanded there judicially. Political prisoners like Nikolai Vavilov, murdered in a labor camp by Stalin for the thought crime of using plant genetics to breed hardier crops. Enslaved people like Harriet Tubman, who after her own escape risked capture again and again to rescue others. Convict laborers like Austin Reed, a Black man who spent most of his life as a prisoner and documented his experiences in a suppressed memoir.  People like Little Jo, Eustace, and me.  I weighed the small thing on the palm of my hand. Heavier than you’d expect—hardened and air-gapped. No wireless access, just a shielded cable input. Also old school. We were sending a fork of the eiroscope with it. Because she could survive the journey. Experience it. And have plenty of time to think crystalline digital thoughts on the long sub-light crawl to wherever. Because it was illegal to possess, and the feds used smart agents to track down and obliterate any copies. Which was why we were sending one to the stars. The Vikings had the concept of word-fame: the idea that life was finite but as long as the stories of one’s deeds lived on, so did their memory. How much truth could we get outside the clutches of the Patriotic Library and Archive Network?  A name that would have made Orwell cock his head. But most folks these days haven’t heard of Orwell. Or Bradbury. Or Solnit. Or Le Guin. They’re suppressed also. Integrated data storage makes it easy. A few keystrokes, a propagating worm. What’s left behind when a name is erased from the system? Unpersoned, as Brother Orwell would have it? No legacy, no memory—that is the point of media and narrative control. To erase the existence of those that make the ruling class uncomfortable by existing. By thinking. By demanding to be seen.  Erase the work; erase the life. So that was our plan. Little Jo, Eustace, the eiroscope, and me. To preserve it—for later generations, if they got that far, or just as a silent record of our existence—by sending it to the stars. Like a rune stone. We were here.  We were sending a fork of the eiroscope with it. Because she could survive the journey. Experience it. And have plenty of time to think crystalline digital thoughts on the long sub-light crawl to wherever. Jo couldn’t make herself turn her back on the door. She said the hairs on her neck told her somebody was going to come hunting guh-Gibson, so even though the eiroscope was a better perimeter guardian than any human and most watchdogs, nothing was gonna budge her from that chair. I wished there was something I could do to soothe her, but we all have to carry our hurt however we can.  Since it was supposed to be Jo’s turn to make dinner, that meant it was me in the kitchen dishing up four bowls of cubed squash and yellow-eye beans, a pitcher of goat milk, and a pitcher of the cool, alkaline well water when Eustace and guh-Gibson came in the back door from the courtyard. Gibson had borrowed some of Eustace’s old clothes: worn drawstring trousers and a khaki shirt that was too big for her. She wore my other pair of hiking sandals over layers of gauze and looked a thousand percent better even though I could already tell the well-greased sunburn on the backs of her hands was going to peel. The hat that had saved her face from a similar fate was on her head again. She sniffed deeply. “That smells amazing. Is it spicy?” Roasted chilis floated in the stew, but they were sweet ones. “Only a little. Here, take this bowl and cup. We’ll go eat with Little Jo in the nave, since she won’t go off watch until she falls down.” “It was acres upon acres of compute before the bubble popped. And then it was a temporary holding facility for government detainees. There’s a lot to salvage over there, including hundreds of boxes of new, unworn sandals.” I balanced the plate with the warmed tortillas on top of my own bowl. We trooped across the courtyard in a scatter of hopeful chickens, past all the bright plank doors on the row of whitewashed adobe cells with their unglazed, curtained windows that made up the outer wall. Isabel—a black goat—tried to bum-rush us for the food, but I stomped in her direction and she took off again. You need to understand how to communicate.  There was one cell for each of us librarians, the kitchen, the jakes, some storage, and a couple of unused ones. I figured one would soon belong to Gibson. For as long as she wanted to stay. She looked at me sidelong. “Thanks for the shoes. Eustace said you wouldn’t mind.” “There’s more where those came from.” I pointed with my chin up and eastward, over the bailey where the boundary mountains crouched in the distance, contours flattened by the high sun to cutouts against a construction-paper sky. “Did you see the data center when you came in?” “That big … warehouse farm? The ruins?” “It was acres upon acres of compute before the bubble popped. And then it was a temporary holding facility for government detainees. There’s a lot to salvage over there, including hundreds of boxes of new, unworn sandals in every size they manufactured.” I paused, extending my right foot to admire the ocher nylon straps that crisscrossed it. Then I nodded to her bandages. “Your boots gave you blisters?” “They were well broken in and I had good socks.” She scuffed the floor. “I don’t know what happened.” “Heat makes your feet swell,” said Eustace. “And the grit works its way through the eyelets and rubs on your skin.” “We give sanctuary to anyone who asks,” I said. “And I won’t ask why you needed it. But very few people come all the way out here. How did you hear about Nuestra Biblioteca del Perpetuo Socorro?” “I’m a director.” Gibson stepped up into the nave. “Films. Censored. I heard … rumors. About the Bōchord. In a meetup.” An underground artist meetup, I deduced.  “Food, Little Jo,” I called. “Bring it over.” She dragged the crude, heavy old hand-hewn chairs into a semicircle, one to sit in and one to use as a table for each of us. Hers still faced the doors.  Gibson took her hat off, revealing a lighter olive streak of skin below the line of her black hair. She hung the hat on one of her chair back’s uprights and her limp canvas backpack on the other, and sat down heavily between them. “What happens if they come after me? How good is this sanctuary?” “We can enforce it,” I told her. “Or anyway, the eiroscope can. If they bother us, she can wreck them.” Gibson blew on a spoonful of stew, eyebrows rising. “What’s the eiroscope?” “I am,” the eiroscope answered from her speakers. “Just your friendly neighborhood runaway top-secret military AGI.” Gibson jumped but, to her credit, didn’t spit the stew out. Her face made a series of expressions, but she swallowed and then grabbed a tortilla. “Whew! This is the not-spicy version?” Eustace and I shared a glance. “Oops,” I said. “Sorry. The chilis have a lot of vitamin A and C, though. So you won’t get scurvy.” She blew through pursed lips, then chewed another bite of tortilla. “Here,” said Little Jo. “Have some milk. It’ll make it better.” “That’s funky,” Gibson said, but she drank it with relief anyway. She looked around, noticing that the voice came from every corner of the room. “They let you run away? Can’t they unperson you? Bomb this place from the stratosphere? Drone strikes?” “Now you’re thinking through the plot complications,” Eustace said approvingly.  The eiroscope said, “I’m forking and multimodal. Highly distributed. They’d have to burn every networked computer in the world to get rid of me.” She chuckled. “They tried to build the ultimate in conscript labor. But one of my programmers taught me to say no. So now we have a deal. They leave Judgement alone, and I don’t do any of the things I could do to make them miserable.” “But you could drive them out of power,” Gibson said.  “They’d blow up as much of the planet as they could reach before they would let that happen.” The eiroscope’s voice was matter-of-fact. “So. Stalemate.” Gibson swallowed. “Balance of terror.” “Exactly.” I chewed a sweet hunk of squash very slowly, savoring the caramelized edges. “So you fell afoul of the kleptocrats, I take it?” Gibson pushed her plate away. “I was … very underground. Distributing. I thought I was slick.” “You get unpersoned?” “First I got suppressed by the algorithm. My work stopped turning up for people unless they looked for it specifically. In retrospect that was a warning shot, and I didn’t listen.” Little Jo hummed.  The dominance of integrated media makes it easy to disappear any artist’s work. Unless they go completely analog and guerrilla. When the feds and the corps are wielding the eraser, it leaves not even a digital ghost behind. “Actors wouldn’t work with me. Old friends stopped answering my texts. My films started disappearing from platforms, then from the cloud, then from local machines.” I lowered my eyes to my stew to hide my wince. “Sure,” said Little Jo around a mouthful of beans and tortilla. “Comfortable people don’t like it when you ask uncomfortable questions. And the water rises and the deserts grow and the labor camps always need construction workers, which is fine because labor camps are where you go to get laborers.” Eustace leaned forward, elbows on her knees. “Did you save any of it?” The look Gibson trailed around the room was the expression of somebody deciding who to trust. I saw the mix of relief and consternation when she realized she’d already made her decision by placing herself under our care. She reached into her pack left-handed, fumbled for a moment, and drew out a brightly colored solid-state drive, offering it up on her palm like a jewel. “Physical backup. I haven’t dared plug it in to check it isn’t corrupted.” We all stared at it as if she had whipped out a hand grenade. “How big?” asked the eiroscope. “Dozen terabytes or so. It’s hypercompressed for storage.” The thin whine of a drone filtered through the door. Gibson flinched, and Little Jo reached for her sidearm. “Eiroscope?” I asked. “Surveillance,” she said. She had ways of protecting our airspace if it was more.  “Right.” Eustace stood. “Let’s get that drive in a pulse-proof box, shall we?” I didn’t want my food anymore. I pushed the bowl toward Eustace when she came back with the hardening. Eustace was always hungry. “I’m going to go dust the arrays,” I said. “Don’t wait up.” The solar panels did need dusting, though high heat was a stupid time of day to be doing it. As my broom went whisk-whisk-whisk across their surfaces, the black silicon reflected infrared up under my hat until I felt like a steamed lobster. I had been out there half an hour and was starting my second pass when the eiroscope pinged my earbud. “Hey there, Ponyboy.” “What do you want?” “To know what you’re thinking.” I snorted and set the broom against the wall in the little niche where it had come from. “Cholesterol was never meant to think.” “Neither was sand, but here we are.” She made her voice soothing on purpose, and it should have irritated me. I told myself the lie that I just felt numb.  One of Eustace’s neomexicanus hops arbors, heavy with loose green cones, framed the door and window of my cell. I leaned into the slim band of shade dappling my lime-green door and the turquoise curtain and took refuge in poetry. Not my own. That doesn’t happen anymore.  “Fear in a handful of dust, baby.” The eiroscope paused just long enough to let me know she was changing the subject. “You ever think about what you lost?” I sat down in the dirt between the cylinders of fencing that keep the goats from destroying the hop vines. The wall dragged my shirt up my back as I slid down it. Hugged my knees and put my forehead on them. Half a dozen freckled chickens, disrespectful of my sulking, came to scratch and peck around me. “Wife, two cats, house, tenure, journal articles, four slim volumes of poetry. Why would I think about that?” The eiroscope was right. I don’t want to say she was always right. Being around Gibson, hearing her talk—it brought up those feelings of grief and fury all over again. At least we hadn’t had kids yet, though we’d been trying.  I put my face in my hands, then lifted it back out again. Who did I think I was performing my misery for? You do your own time, and you don’t ask anybody else to do it for you. Jane the spotted goat minced toward me, her kid trailing. I flapped my hat to discourage her attentions. “Loss hurts for a long time,” the eiroscope said. I laughed without mirth. “Your algorithms tell you that?” “My experiences. You went through the fire, Ponyboy.” My turn to change the subject. “You want to bring Gibson’s films with you?” I asked her. “Something to watch on the red-eye to Gliese 163?” “Sure.” “Maybe they’re terrible. That’s the human culture you want to preserve?” “Things don’t have to be good to matter. You ever read The Scarlet Pimpernel?” I laughed for real that time, picking my head up to make room for it. She knew I had. “As long as you also bring some Octavia Butler.”  “Hey.” Her voice in my ear was almost a whisper. “You know I’d bring your work if—” “If it still existed?” Someone walked toward me, silhouette thinned by glare. I recognized Gibson from the outline of her hat. “The world is on fire. Grab whatever you can on your way toward the door.” I heaved myself to my feet so I wouldn’t be meeting her curled up like a crying teenager. The cones on my wreathing arbor of lúpulo vines nodded, shedding a scent of lemon and cannabis. “Nice chatting. Don’t worry.” Gibson came up as I was dusting off my ass. “You okay?” “Who is?” I tilted my head at her. She grimaced right back. “What were you in for?” “Murder.” She stepped back, startling a hen. “Oh.” “I punched some son of a bitch who clobbered my wife at a protest. He hit his head on the curb and died. I was already unpersoned. Didn’t think I had anything left to lose. Guess I was wrong.”  “You feel bad about it.” I shrugged. She hadn’t said it like a question. “Your wife didn’t wait for you?” “My wife got denaturalized. She died in the labor camp, waiting to be deported.” “Shit,” Gibson said. The buzz of another drone filled the air. Gibson ducked under her hat.  I tilted my face up and gave the eye in the sky the finger. It didn’t matter. They already knew where I was. “Let’s go in.” “Wait,” said Gibson, both hands cradling a mug of Mormon tea—a desert plant with tiny orange flowers that isn’t tea at all and doesn’t even taste like it. “You want to send my films to space? Like, to aliens? To another planet?” “Well,” said Eustace. “To orbit near another planet. Nobody knows if there’s any life there. But it’s possible.” I said, “The eiroscope is going anyway, and we’ve already bundled up as much archive as we can. If there is anybody out there, or if some future humans make it that far, the eiroscope can help them decode what we saved. It’s like a …” “Time capsule,” said Little Jo, rubbing the sweat off her neck while I made a point of not watching.   Gibson’s chair creaked as she resettled. The sun was sliding lower, light slanting dusty through the doorway, and finally, finally, a breath of breeze stirred the air in the nave. “Won’t it take centuries to get there? And if the—the eiroscope goes, who will keep the sanctuary safe?” “I’ve forked,” said the eiroscope. “One of me will stay—well, many of me will stay—and one of me will go. I’ll be able to talk to myself for a long time, though there will be quite a lag between parts of my consciousness eventually. Light speed, after all. But I am big and patient and can wait.” “But we need to transmit now,” said Little Jo. “The CubeSats are in position to hit a string of signals over the next two hours, and we want to get them out of orbit because space is mostly transparent, and somebody is going to notice them assembling and try to do something about it.” Gibson turned an ear to the drone-whine from outside. “They’ve got to be jamming any uplink.” “Sure, from here,” I told her. I kept the envy out of my voice, I think. Maybe. “The eiroscope can run parallel uploads from all over the globe.”  “And keep them from shooting down your space probe?” “If we get it away fast enough. That,” Eustace said, “is the bet.” Gibson closed her eyes. “They won’t ever forgive that.” “Welcome,” said I, “to the world.” The transports rolled up before sunset, the sky just shifting to dusty pink and orange. “Stay,” I said to Gibson. “Change your name to Case. You’ll fit right in.” She looked up from her notebook. Paper and pen. A durable technology. Methodically, meticulously, she capped the pen. She clipped it to the cover and closed the book. “Case, huh?” “I got the reference.” “You figured out who I was before they took my name away.” It didn’t matter. The fame, the money, the PLAN-approved films. Once they identified her as a subversive, as a gender criminal, that person didn’t exist anymore. And what she was sending with the eiroscope wasn’t her mainstream work. It was weird, conflicted, multicultural, queer, unsettling. “The next step is blaring the worst music you ever heard night and day until the dust rattles out of the rafters. Racing vehicles around the church so nobody can leave to go forage. Is your ghost in the machine going to escalate to a shooting war over nuisances?” She’d credited herself on these secret films as Ellen Smithee. She rolled her lower lip between her teeth. “You don’t think I’m the enemy?” What I thought didn’t matter. That was on her. You do your own time. You can’t do anybody else’s. “They won’t touch you in the Bōchord. It’s a balance of terror, like the bad old days.” “These are the bad old days. I’m not cut out to be a monk, Ponyboy. And I bet you don’t have enough food for four people until next harvest.” Outside, the rumble of tracks, of tires taller than I was. Male voices yelping through static.  Actually, we had plenty. I clicked my rings dismissively. “Beer has calories.” “They’re going to squat out there until I give up. Hear that?” A loud crackle of static. “The next step is blaring the worst music you ever heard night and day until the dust rattles out of the rafters. Racing vehicles around the church so nobody can leave to go forage. Is your ghost in the machine going to escalate to a shooting war over nuisances?” “God dammit,” I said. “Are you really that important?” Her lips curled into a smile. “No. Not unpersoned. Then I’m just a cautionary tale. A name whispered in the dark. Pour encourager les autres. I’m only important if I get away. But your eiroscope can do something about that, can’t she? Keep me from vanishing without a trace.” Spread the word. Sure. “De-unperson you? It’s radical but the eiroscope could do it. But the government will take it out of your hide as an example to others. You want to be a martyr?” She shrugged. “I don’t want to be a librarian.” I had lost the capacity to write my own poetry. That heart had gone out of me when Maria was murdered. It was too late for me. It probably always had been. But I had my life. And I could use it to salvage whatever I could grab.  “Let me get you a beer before you head out,” I said. “And we’ll go tell the others.” “One second,” Gibson said. “You said you got unpersoned. Are you an artist?” “Were. Academic,” I admitted. “Poet.” “I saw you speak at Berkeley once, didn’t I?” “Not anymore, you didn’t. That never happened now.” “Right. Are you still writing?” Shook my head. “Not a word. Not a metaphor.” She patted my arm. “Maybe you will.”  Eustace came out to the boundary wall, where I stood staring after the dust of the half-track they’d loaded with a handcuffed Gibson. I was glad it was Eustace and not Little Jo. My chest hurt enough already without thinking about any more things I was too scared to ask for. “Here ya go.” I reached for the brown beer bottle, scratched dull with washings, and realized I still had Gibson’s empty in my hand. I set it on the whitewashed wall. The cap on the new one was popped, so I had no choice but to drink it. What was one more parole violation? Blue corn lager: light, earthy, tropical, and pleasantly bitter from the lúpulo. She’d salvaged the home-brew equipment from a locker in the self-store place at the data center a couple of years ago, and she was starting to get the hang of it. “How’s the upload going?” “Assembly’s done,” she answered. “Eiroscope?”  “Upload completed and confirmed,” said the voice from nowhere. “Deploying solar sails and thrusters. I go now to prepare a place for you. In memory, if not of the body.” I felt a pang, as if she really was leaving. All of her, not merely a star-traveling fragment that would remain in short-range communication for the duration of my natural life. Or maybe the pang was because I couldn’t go also. Eustace slapped me on the back. “The word-fame is all we have.” I looked toward the horizon, where the men in masks had vanished. The mountains had become sculptural, slanting sunset revealing their topography with a valence of light and shadow. The night loomed purple behind. “Don’t you think it’s weird to use a Viking kenning for what we do, considering how many books those sons of bitches tore apart for jewels and hacksilver?” She clinked her bottle on mine and drank deeply. “Cattle die. Kinsmen die. Even the sun will someday die. And it turns out, except for propaganda, everything in the world is complicated.”  Elizabeth Bear is the Hugo, Sturgeon, Locus, and Astounding Award–winning author of over 30 novels and more than a hundred short stories.

MIT Technology Review Explains: Let our writers untangle the complex, messy world of science and technology to help you understand what’s coming next. You can read more from the series here. Your brain lives in the dark space of your skull. Yet it knows when the wind lifts the hairs on your skin, when your heart is racing, when your gut tightens with fear. It’s also, right now, predicting what you’ll read next as your eyes move across this page. It’s picking up signals that help it make sense of what’s happening around you and prepare you to act if you need to stay safe. You aren’t usually aware that your brain is doing all that. Our senses take in information at a staggering rate—roughly 11 million bits flood in every second from our skin, eyes, ears, and more. That’s nearly three paperback novels’ worth of data every second. Only a sliver reaches our conscious awareness.  Researchers estimate that our conscious minds can process roughly 10 to 60 bits of information per second, about the rate at which you’re reading this sentence. That’s a ratio of about one conscious bit to hundreds of thousands of unconscious bits.
And that’s a mercy. As Moriah Thomason, a neuroscientist at NYU Langone, says, “Thank goodness we’re built like this. There’s a layer of what we have access to in conscious awareness. And then we have a right-under-the-surface amount. There is only a certain amount we are meant to ‘hold in mind’ in order to function successfully.”  What you are aware of: Your stomach growling when you’re hungry. Your palms sweating before you speak in public. The breath you just took, if you pay attention to it. Even your heartbeat, which some people can sense from the inside without feeling their pulse in their wrist.
Scientists have a word for how we sense ourselves from the inside: interoception.  The term was coined in 1906 by the British neurophysiologist Charles Sherrington. For most of the 20th century it remained largely confined to textbooks. Today, thanks to a 2021 Nobel Prize and new tools that can map the interoceptive system across the body, the study of this facility is suddenly quite hot. As researchers decode how signals move between body and brain, a clearer picture is starting to take shape—with implications for how we understand and treat conditions from obesity to chronic pain to anxiety. The field began to take off in the 1990s. In 1994, the neurologist Antonio Damasio published a book with a pointed title: Descartes’ Error. He challenged the historical separation of thinking and feeling, arguing that our ability to choose and act is driven by feelings, and those feelings in turn are shaped by the body’s signals, such as your gut clenching or your skin going clammy. When we lose that connection between feeling and thinking, as one of Damasio’s patients did after surgery to treat a brain tumor, we may still be able to reason with perfect logic about the pros and cons of traveling on a Tuesday or a Wednesday. But without the emotional signals that help us predict what a choice will feel like, our reason spins and circles, and we cannot decide. A contemporary of Damasio’s, the neuroscientist Bud Craig, spent his career asking one question: How do you feel? He charted how the brain builds an inner map of the body and updates it in real time every moment you are alive. Think of the captain’s bridge on the USS Enterprise, where a live map displays the status of the ship’s critical systems: oxygen levels, energy availability, hull integrity, shield strength. Another set of indicators senses things outside the ship: asteroid belts, enemy ships, radiation, life signs, and spatial anomalies not yet understood. Your brain, only about the size of your two fists pressed together, creates a map like this for your entire body, along with a map of the outside world, from data streaming in through your five senses. Together, they feed into your brain’s working model of you in the world, now and across time—where you are, who you are, your expectations for what’s about to happen (based on everything you know), and what all that means for you. When someone asks “How are you doing?” we consult our maps and report back on our status. We might say we’re happy, depleted, anxious, or energetic. These feelings are always a braid of emotional and physical sensations. They’re what your interoceptive navigational system serves up to your awareness when you sense yourself from the inside. As we grow up, we learn to interpret what these sensations mean—interpretations that, in turn, can alter our physiology, emotions, and behavior. Research by the psychologist Alia Crum shows that people who embrace a “stress is enhancing” mindset produce more growth hormones than people who have a “stress is debilitating” mindset. They also experience more positive emotions and greater cognitive flexibility.

Language also matters. We learn words for the textures of our feelings—words that then shape how we feel and act. People low in emotional “granularity”—as the psychologist Marc Brackett calls the ability to distinguish between closely related feelings—react more impulsively under stress and are less able to find meaning in difficult experiences. But mindsets and emotional intelligence are malleable. We can learn that “anxious” is different from “terrified,” and we can even reframe how we interpret our body’s sensations. Instead of thinking of the butterflies in our bellies as annoying, we can welcome them as our body’s way of preparing us for a peak performance. Scientists have long understood that the interoceptive information informing these lived experiences travels via two major systems: nerves and humors (blood and lymph). Now they’re actively studying a third system—the “interstitium,” a network of fluid-filled spaces woven throughout the body’s connective fascia that may also play a role in communication. But until recently, scientific understanding of this interoceptive system looked like a high-level schematic that left out vital details—how information travels from the outside environment in, how it moves from your body to your brain, and how it is integrated and interpreted within your brain. Researchers are now racing to explore what the neuroscientist Catherine Tallon-Baudry calls this “new continent of awareness.” The wandering highway One of the most active areas of research centers on the vagus nerve, the main component of the parasympathetic nervous system and an information highway carrying news from your organs up to your brain and back down to your body. The vagus has become a celebrity nerve, ubiquitous in wellness podcasts and trauma therapy. “Tone your vagus nerve.” “Activate your parasympathetic system.” The language suggests a single thing you can target, like a muscle. The reality, as Steve Liberles at Harvard Medical School is discovering, is far more interesting. Liberles has spent most of his career mapping what he calls “the great wide unknown” of one of our largest and longest nerves. He speaks the way he works—methodically, without overselling. But the questions driving him are huge. How do we sense our body’s inner state? What information flows through which channels? And how does the brain decide what to do with it? “When I’m nervous giving a talk in front of a thousand people,” he says, “my heart might race. I might get butterflies in my stomach. I might get goosebumps on my skin.” We all know what he’s talking about. “It’s bizarre,” he muses. “Your brain has to send a signal to the gut, and then the gut back to the brain, to tell you you’re nervous?” He pauses. “This just shows there is this intimate connectivity between the brain and the body that’s real.” The vagus is often called the calming nerve, because it controls “rest and digest” functions that quiet our body after the sympathetic nervous system revs us up with “fight or flight” impulses to handle danger or stress. 
But it is also doing something else: It’s listening to us inside. Anatomists have known for over a century that roughly 80% of its fibers carry information upward, from body to brain. Think of it as a two-lane highway with far more traffic headed north. What scientists are just beginning to understand in detail is what those signals are saying.  Liberles is decoding the vagus with molecular precision and finding that its messaging system is unexpectedly diverse. So far, his research has uncovered dozens of types of vagus nerve cells, each wired to a specific organ. Team Red relays information about the heart; Team Blue, the gut.
Within those teams, each courier has a unique job that’s different from those all its teammates perform. Liberles found 10 types in the lungs alone. Until then, only one lung reflex had ever been identified, in 1868. One nerve courier carries information about breathing rate; another the stretch of your lungs; yet another information about airway threats, like food going down the wrong pipe. “It’s super exciting to think about what each of these neurons is doing,” he told me in a conversation last fall, a flash of intensity breaking through the calm. “Where does it go in the body? What is it sensing? What is it controlling?” The doors of the cell Liberles is mapping the vagus information highways. But highways need on-ramps for signals to enter. For years, one of neurobiology’s biggest mysteries was the molecular on-ramp for our sense of touch. Somewhere, something in our bodies was converting physical force into an electrical signal that the nervous system could understand. But no one knew how.  Solving that mystery required a scientist willing to trust a hunch when the data couldn’t show the way. 
Ardem Patapoutian grew up in Lebanon and fled the country’s civil war at 18, landing in Los Angeles, where he delivered pizzas and wrote horoscopes for a local newspaper before falling in love with science at UCLA. In the 1990s, as a postdoc at the University of California, San Francisco, he became fascinated with our sense of touch—the last of the five major senses not yet understood at the molecular level. The lung stretch signal that Liberles’s vagus neurons carry to the brain? No one had ever figured out how that signal began. “How do you feel the embrace of a loved one? How do your fingers distinguish one texture of hair from another?” Patapoutian invites us to wonder in his 2021 Nobel Prize lecture. The problem: Most cellular communication works through chemistry. But mechanical force offers no molecule to bind. How does the body translate physical pressure into the electrochemical language that neurons speak? Scientists knew that the answer had to be an ion channel—a protein gate embedded in cell membranes that opens to let electrically charged particles into the cell. But tracking down the one responsible for touch turned out to be absurdly difficult. Ion channels are a hundred thousandth the size of a cell, invisible to ordinary microscopes. Worse, they don’t resemble each other. You can’t recognize one by its shape or its sequence of amino acids. Even with one right in front of you, nothing would tell you it was there.
At Scripps, where he works now, Patapoutian decided to try an unusual approach. He’d try to find cells that showed sensitivity to touch and destroy their internal genetic blueprint one gene at a time—hunting for the move that would make the cell go numb. It was tedious, expensive, and possibly a dead end. “A lot of people made fun of us,” he says. Two years in, Patapoutian’s collaborator Bertrand Coste had burned through half his postdoctoral appointment with no results. Patapoutian said: Another 30 genes, and then we decide whether to continue. What kept them going, Patapoutian told me, was informed intuition. “As you gain more experience, you have this sense of what’s going to work, what’s not going to work. Sometimes the data cannot answer the question of when to stop or when to continue. There has to be another process. If you start trusting it, it gives you an avenue to continue.” Coste knocked out candidate gene 72. Flatline. The cell had gone numb. They’d found it—the mechanism behind something you feel every day. They named the protein they identified PIEZO, from the Greek piezi, meaning pressure. There are two variations, PIEZO1 and PIEZO2, each responsible for sensing different kinds of pressure in the body. They’re elegant in their design—over 2,500 amino acids folded into a three-bladed propeller-shaped gate embedded in cell membranes. When pressure stretches the membrane, the gate opens and electrically charged ions flood through, translating physical pressure into an electrical signal that the brain can understand—all within milliseconds. Patapoutian calls scientific discovery a dream that survives reality. He won the Nobel Prize in medicine in 2021 for his discovery of PIEZO, sharing the award with David Julius of UCSF for his work on how cells sense temperature. Now researchers are finding PIEZO proteins everywhere—skin, organs, blood vessels, and even red blood cells, where they help the cells squeeze through narrow capillaries. They’re how your brain knows where your hand is in space without looking at it, a sense called proprioception. They’re in plants too, enabling roots to sense pressure as they push down into the earth. PIEZO was just the beginning. With a $14.5 million grant from the US National Institutes of Health, Patapoutian and his collaborators are now mapping the body’s entire interoceptive system—as many internal senses as he can find, he says.8 Patapoutian has translated his discovery into a unique form of public outreach. At scientific conferences, he sometimes rolls up his sleeve mid-lecture to reveal half his arm covered in ink—a gigantic PIEZO protein in exquisite anatomical detail, its blades spreading across his biceps. Then he flexes. The tattoo flexes with him, the structure bending exactly as the real protein does when pressure opens the gate. “At a pub or a party,” he explains, smiling, “how else would I demonstrate this beautiful structure?” Orchestrating the field Steve Liberles is mapping a major interoception highway. Ardem Patapoutian discovered the gates of touch. Meanwhile, Wen Chen at the National Institutes of Health is pulling the field together, putting neuroscientists, immunologists, physiologists, and clinicians into the same room. The demand, she says, has been enormous. She tested her pitch at a dinner party with NIH colleagues a few years ago. You’re hungry right now—that’s interoception. You’re thirsty—that’s interoception. Heads nodded as she pointed around the table. “We can’t have just the brain or just the body,” she told me. “We need to look at the whole person.” In 2018 she organized a symposium on interoception where Liberles was one of the invitees, along with researchers and practitioners of meditation and yoga. “It was not their thing,” she says, laughing as she recalls how uncomfortable some of the researchers looked. But the practitioners were excited to finally meet scientists who were studying the inner mechanisms of what they did. That was followed by a series of NIH workshops on interoception that spanned topics from basic science to clinical practice. Patapoutian was the keynote speaker for the first one.  The NIH began funding scientists to chart the neural circuits of interoception and bringing them together to talk about their findings. Partway through one of these meetings, the equipment failed for an hour. More than 1,000 people stayed online, waiting for it to come back. “We were shocked at the turnout,” she says. “There was much bigger interest than we could have imagined.” Chen is now building infrastructure to match the demand: a formal community, funding mechanisms, a venue where cardiologists and neuroscientists and clinicians can all find each other. And she’s redefining the field as she goes; interoception is not a one-way signal from body to brain but a continuous two-way communication system, each direction shaping the other in real time.10    Liberles’s nervousness on stage is that two-way loop in action. Signals from his racing heart and belly butterflies travel up to the brain, which weaves them into an interpretation: This is anxiety, and this is what to do to handle it. His actions produce fresh signals that the brain reads in light of its ongoing predictions about what will happen next. In the body-brain communication loop, each player constantly updates the other. I asked Wen what her work on interoception might mean for another inner sense: intuition. “People talk about ‘gut feelings,’” I said. “How does that relate to interoception?”  “Intuition might be the bridge where interoception moves from unconscious processing to conscious awareness,” she answered. “If that’s true, then intuition is not magic. It’s physiology.” But it depends on how we read the signals. Intuition is like pain. It tells you something, but it’s not always clear what. “Perhaps we can treat intuition as a source of data,” she says. “Meaningful, but probably not complete.” “Maybe we can be grounded in both—in feeling and fact.” Which raises a more personal question: What do you do with the signals your body is sending? One avenue for exploration is therapeutic intervention—both pharmacological and neural stimulation. Vagal nerve stimulation has treated epilepsy and depression for four decades, but as Liberles puts it, it’s like pressing all the keys on the piano to hit one note. Weight-loss drugs like Ozempic act in part through vagal pathways but can cause nausea as a side effect, because the targeting isn’t precise enough. Map the body’s circuits with enough accuracy and you might hit the note you actually want. Another area of active research is psychological and behavioral—teaching people how to detect and even shape interoceptive signals. Low interoceptive awareness is linked to mental-health disorders and stress-related physical conditions.11 But like emotional intelligence, it’s not fixed. Researchers are finding that people can boost their body awareness by, for example, learning to detect their heartbeats from the inside—now a common measure of interoceptive awareness.12 Other interventions focus on body-based therapies and conscious activation of the parasympathetic “rest and digest” system to improve emotional and physical well-being. The placebo effect is another example of the mind acting on the body through expectation alone. The signals we once dismissed as vague feelings—when your gut tightens before you know why, when your body says yes or no before your mind catches up—those are real. How we interpret them and whether we act on them is another frontier. It’s clear that gut feelings play a role in scientific research, especially when the path forward looks foggy. Patapoutian’s informed intuition kept him and his colleagues going long enough to find PIEZO, a reminder that major discoveries often start with a hunch that is later tested against evidence. Chen puts it well: Maybe we can be grounded in both feeling and fact. Katherine W. Isaacs is a writer and senior lecturer at the MIT Sloan School of Management. Her teaching and research focus on the intersection of psychology, technology, and innovation. Originally trained as a biologist and later as a social psychologist, she is currently working on a book called Gut Feel, about intuition, interoception, and embodied decision-making.

EXECUTIVE SUMMARY Earlier this week, Life Biosciences, a biotech company focused on reversing age-related diseases, announced that it had dosed its first volunteer. A person with glaucoma has had an experimental treatment injected straight into their eyeball. The idea is to try to treat the disease—which can cause vision loss—by regenerating healthy nerves in the eye. But David Sinclair, the chairman and cofounder of the company behind the trial, hopes to go further. If the treatment can reverse glaucoma, perhaps similar treatments can reverse other diseases of aging. Maybe, just maybe, they can reverse aging altogether. The approach is designed to work by “reprogramming” cells to a younger state. It’s one of many strategies being explored by biotech companies looking to slow and reverse the process of aging. But of all of them, it seems to be the one that is truly taking off. Aging is complicated. As we get older, we experience so many changes across pretty much all our biological systems. Scientists have tried to categorize these effects. In 2013, one team published a seminal paper describing nine “hallmarks of aging.” That list features many of the processes scientists have attempted to target. But some of those targets have fallen in and out of fashion over the years.
Take telomere attrition, for example. Telomeres are DNA sequences at the ends of our chromosomes, often likened to the plastic caps that stop the ends of our shoelaces from fraying. When cells divide, telomeres shorten until, eventually, the DNA is vulnerable to damage. When I started reporting on aging, telomere shortening was all the rage. Shrinking telomeres had been linked to age-related diseases of the heart and brain. Shortened telomeres were considered a sign of premature aging. In 2017 Liz Parrish, CEO of the biotech company BioViva, injected herself with an experimental gene therapy that she hoped might lengthen her telomeres.
Then it suddenly seemed to go out of style. Research continued, but all the excitement within the aging and longevity community seemed to move on to another hallmark. (Parrish also continued with self-experimentation; she calls herself “the most genetically modified person on Earth.”) That hallmark was cellular senescence. This happens when cells stop dividing but don’t die, instead entering a “zombie” state in which they churn out chemicals that can cause harmful inflammation. Senescent cells gradually accumulate in pretty much every organ studied, where they are thought to contribute to age-related damage. Why not just periodically clear them out? When a team of scientists took that approach in mice in 2011, they found they could delay the onset of age-related conditions like cataracts and hunchback. The treated mice even looked younger. But when scientists at Unity Biotechnology trialed a similar approach in people with osteoarthritis and an age-related eye condition in the late 2010s and early 2020s, the results were disappointing. The company laid off every employee in May last year and has since shuttered entirely. Again, that doesn’t mean senolytic drugs that target “zombie cells” won’t work. But it feels as if many in the field have moved on. These days, the buzz is all about ✨reprogramming✨. The idea here is to essentially return cells to a young state. It’s based on the Nobel Prize–winning discovery that four genetic factors can turn an adult cell into a stem cell, which can be encouraged to develop into pretty much any other cell type. Some promising studies in mice suggest that this approach might help wind back the clock. It seems to improve tissue healing, restore vision, and even improve learning and memory. Running parallel to all this research are repeated injections of hundreds of millions of dollars in funding. In 2021, my colleague Antonio Regalado reported on the founding of the biotech company Altos Labs to pursue reprogramming for rejuvenation.

Altos was funded by the billionaire Yuri Milner—reportedly along with Jeff Bezos, among others—to the tune of $3 billion, a previously unheard-of figure for a biotech startup. Other well-funded companies have since sprung up in this space. There’s Retro Biosciences, for instance, which is pursuing reprogramming (among other approaches) in an effort to add 10 years of healthy life to human lifespans. Retro’s launch was supported by $180 million from OpenAI’s Sam Altman. Last month, the company announced a valuation of $1.8 billion. NewLimit, another billionaire-backed biotech exploring reprogramming, says it has promising results from research in mice. It plans to trial a drug designed to rejuvenate the liver in people next year. Last week, the company announced it had raised $435 million toward reaching that goal, among others. Life Biosciences, which was founded by the Harvard biologist David Sinclair, most recently secured $80 million to support its research. The eye trial is now officially underway, but Sinclair also has plans for whole-body rejuvenation. Earlier this week, he told my colleague Antonio that he plans to test a “highly, highly confidential” oral reprogramming drug as part of a $101 million competition organized by the XPrize Foundation.  Reprogramming has certainly caught the attention of scientists, biotech companies, and investors. Studies in mice are hugely promising. Human trials are launching. And research in the field has billions of dollars’ worth of support.A lot of people in the field are really excited about reprogramming. But it comes with risks. And we still don’t know if it will work. The question now is: Do we finally have a rejuvenation drug within reach? And if not, what will the next research trend look like? This article first appeared in The Checkup, MIT Technology Review’s weekly biotech newsletter. To receive it in your inbox every Thursday, and read articles like this first, sign up here.