Extinction awareness is the human trait Mason wants to carry to the stars

Chris Mason's book *The Next 500 Years: Engineering Life to Reach New Worlds* is dedicated "to all humans and any extinction-aware sentience." Asked by Lex Fridman how fundamental that awareness is, Mason does not treat it as a morbid hobby. Contemplating not just your own death, or your family's, but the loss of everyone like you is, he says, one of the few traits that may belong to humans alone. It sounds scary. He wants it understood as exemplary.

At the individual level, a deadline is a creative force. At the species level, religions have long encoded some version of the world's birth or death, but Mason argues the threat has become quantified in the past few centuries, especially the past few decades. Terraforming Mars would only be the second planet engineered at planetary scale. "We're already doing it for this one, just not that well." The off-site backup, in his language, is a duty.

Duty, he admits, usually puts people to sleep. Soldiers wake up with a concrete duty to country; most people feel it toward a spouse, a child, a parent, then bury it in daily life. What has never existed, Mason says, is an overarching duty felt as a species toward generations not yet born. He wants the same tooth-and-nail protectiveness people show their families extended to the rarity of life — especially extinction-aware life, which so far is us. He hopes we are only the first such minds, not the last.

That same window of history now includes the power to prevent death at the species level. Mason sits on the advisory board of Colossal, which is trying to bring back the woolly mammoth, perhaps in three or four years. Fridman, who has been wrestling with database backups, notes how much damage a bad restore can do. Mason agrees: deleting a species from an ecosystem can be catastrophic, and adding one back can be too. The technology exists. The guidelines do not. The best science, he says, is both dangerous and exciting, which is why the people pushing it have to be morally grounded as well as technically good.

Late in the book Mason treats the heat death of the universe as something worth fighting, and Fridman says the passage knocked the melancholy out of him. The usual story is that all things end, so nothing finally matters, so beauty lives only in the moment. Mason's ethic is the other one: tell me the problem and we will try to solve it. If humans last long enough to hop from sun to sun, they still meet a universe that, on current evidence, keeps expanding until everything is too far apart. With a deep enough grasp of physics and spacetime, he thinks we would try to restructure the shape of the universe itself.

He ends every interview — graduate students, medical students, faculty — with the same question: how long will humans or our evolutionary derivatives last? The answers range from a hundred years to as long as the universe. One medical-school applicant said a hundred years, everything gone. Mason asked why not sell bananas on the beach. The student said he wanted the last few hundred years to count. "That's actually kind of hopeful in a really dark way." Mason's own view is that humanity has never been better placed to last, and never more able to destroy itself.

He cites Toby Ord's *The Precipice* and the first nuclear test: the math was incomplete, the error bars too large, and they still were not sure the chain reaction would not destroy Earth or the universe. They tested the bomb anyway. That, Mason says, is the stage we are at as a species. The same power that could end the story is also the power that could get us to other planets. Voyager's nuclear batteries are still ticking past the heliopause. A tool or a weapon, he says, depends on how you hold it.

Are we alone? Mason thinks bacterial life is likely, because on Earth life has turned up in salt, cold, and almost every other niche. Sentient life, as far as we know, is still just us. Enrico Fermi's "where is everyone?" is, he argues, the wrong question. Earth is 4.5 billion years old; complex life is a few hundred million years old; humans are a few million. The universe itself is about 13.8 billion years old and spent the first five or six billion cooling, making stars, and waiting for supernovas to scatter the elements life needs. The useful question is not where everyone is. It is when everyone else is getting here.

"I think we are the first ones at the party. Let's set up the liquor. Let's set up the food." He would also revisit *Star Trek*'s Prime Directive. If you pass a planet whose people will never leave, and you know their star will engulf them, and you could help, refusing to interfere is "watching a train hit someone on the tracks and not moving the train." Cheap, structured messages — Carl Sagan's prime numbers in *Contact* — are worth sending. We have already been leaking radio for nearly a century.

The stock critique of spaceflight is that the money should cure poverty and disease. Mason's answer is that you can walk and chew gum: the United States passed the Civil Rights Act and went to the Moon in the same decade. CRISPR was 25 years of unfashionable work on odd bacteria in hypersaline lakes before it became a household word and a therapy. Oceanography and neuroscience forced new ideas in data and computing. Looking for aliens, he says, sits on the line between fear and beauty and pulls in the young, the old, scientists, artists, and entrepreneurs at once.

Most terrestrial life is neither helpful nor harmful; it is just making its way. The same, he hopes, will be true of whatever comes back from Mars with the sample-return planned for 2033, though Michael Crichton's *The Andromeda Strain* remains the nightmare. Textbooks say viruses are not alive because they cannot replicate alone. Mason would rather define life as the autonomous aggregating and replicating of information — which is also the test he would apply to an AI that continually propagated instructions for its own existence. Viruses never asked permission to express themselves. When, Fridman asks, will humans allow an AI to say it is alive?

NASA planning meetings for the Twins Study, Mason says, often opened with Eisenhower: "Plans are useless, but planning is essential." Craig Kundro would throw the slide up, and Mason never knew whether the day would go well or badly. The quote is the frame for a thought experiment he calls entropy goggles. Sit in any room and imagine it in 10 years, 100, 500, thousands. Almost nothing you are looking at will be there. The first feeling is terror. The second, if you let it arrive, is liberation: you can prevent some of the decay, redirect some of it, improve what would have happened on its own.

Strictly speaking, living things still increase total entropy — we leak heat; no conversion is perfect — but we are among the only processes that consciously rearrange the universe against the second law. Ants do it when they build nests. Humans can do it at planetary scale and on timelines of centuries. Mason shows first-year medical students charts of the body falling apart and names the plot "the inexorable march towards molecular oblivion." The 22-year-olds laugh. Older people do not.

He chose 500 years because a million is too foggy to plan and two years is just the news cycle. Greek tragedy still reads in high school; some of the human condition is stubbornly stable. Five centuries is long enough, in his view, to settle the Moon and Mars, mature space medicine, and prepare a generation ship. He is "matter agnostic" about cognition: carbon or silicon, if it is clearly intelligent, congratulations, and the duty still applies. He wrote the book for future AIs too. Biology remains useful even then. DNA, with redundancy and cold storage, may outlast hard drives as a millennial archive.

Mason became a geneticist the day he learned that one embryonic cell holds instructions for every cell type in the body. DNA is the static recipe, about three billion letters of A, C, G, and T, and some 60,000 genes. RNA is the recipe read aloud; proteins are the enzymes that keep the kitchen running. Almost every human trait mixes nature and nurture. Height draws on 50 or 60 genes, not one. Twin studies estimate heritability: religion as a brand has essentially zero genetic correlation, while religiosity and even boredom susceptibility (about 30 percent heritable) do not. The machinery *is* the information. That, to him, is the most beautiful fact in the universe.

Scott Kelly spent 340 consecutive days in space, then the longest U.S. mission, while Mason's team profiled DNA, RNA, proteins, and small molecules. Space is rough; the body is "amazingly and monstrously responsive." Fluids shift, faces puff, cytokines spike. Some astronauts stay stressed the whole mission; Kelly spiked, then was "cool as a cucumber." The shock was return. After a year without weight, even a T-shirt irritated his skin into a full-body rash. Inflammation settled in three or four days. Many space-activated genes were still on six months later. After about a year, 99 percent had returned to preflight levels — cellular jet lag.

Radiation in orbit is roughly three or four chest X-rays a day. The team saw DNA-repair machinery working overtime and damaged bases such as 8-oxoguanine in urine. Telomeres, the chromosome caps that usually shorten with age, got *longer* in space, the opposite of the prediction. They have now seen the same lengthening in 59 other astronauts. Mason will not jump to lifespan claims from a notoriously underpowered study, but 260 samples over three years, plus mice, suggest a kind of cleansing — hormesis, a low dose of stress that primes the system, the way some clinics already use low-dose radiation to stir immune cells.

Radiation is the dominant long-mission risk, and Mason does not want only to measure the damage. Cells already run protein machines that scan DNA for nicks and breaks. His lab can epigenetically CRISPR those repair genes on before irradiation, changing how DNA is packaged without rewriting the sequence. Similar reactivation — turning fetal hemoglobin back on — has already cured sickle cell disease and beta-thalassemia. He would also want electromagnetic shielding and physical defenses outside the body. "We're taking the same passion to keep astronauts safe that's outside them and just putting it in their cells." He does not think astronauts are ready now; the book aims at about 2040, after terrestrial trials.

A lifetime spent purely in free space, he thinks, still needs some gravity — orbital platforms at least, or Mars at 38 percent of Earth's pull. Lava tubes, caverns left by old flows, could be inflated into habitats with soil overhead as radiation cover; JPL has discussed sending a helicopter into one. Food is the other bottleneck. Freeze-dried upmass is not self-reliance. He wants bioreactors, fermentation, and even prototrophic humans who can make all 20 amino acids and their own vitamins. The GULO gene for vitamin C still sits in our genome as a broken pseudogene; wet-nosed primates never lost it. Reactivate it carefully, in cells then animals then people, and you need fewer limes on the way to Mars. He still does not want anyone to become a robot about flavor. Taste and smell already fade in flight.

NASA's official stance is that there has never been sex in space. Mason, citing Greek tragedy and human predictability, doubts that is the whole story. Sperm has been flown and used in IVF; mice and worms can reproduce in flight; human gestation in zero-g is unknown. Inspiration4 showed that a cancer survivor with a prosthetic limb, Haley Arceneaux, can fly and be profiled like Kelly. As more "regular Joes and Janes" go up, he expects the Greek drama — love, hate, privacy, Velcro — to follow. Colonizing Mars is not, by Earth Similarity Index, the best world (Mars sits near 0.7, Earth is 1.0), but it is close, cold enough to seal against, and better than Venus unless you live in the clouds.

Even the word *colonize* is a social problem. Daniel Wood at MIT studies the baggage; *settle* is not clean either. Mason prefers explore, build, survive. History, he concedes, is a dark ledger of exploitation and murder, written when life was brutish and short. His hope is that a longer-lived, more inclusive species can keep commons — parks, untouched zones — the way shorelines stay public a few hundred feet inland. Technically the work is still brutal: live underground, scrub perchlorates from soil, pull water that NASA maps show is widespread a few feet down, and manufacture buildings from local regolith. True independence, in the book, takes several hundred years. Beer, eventually, would be a leading indicator.

Motivation still looks like a race. China has talked about boots on Mars by 2033, two to four years ahead of NASA's public timeline. India, the UAE, ESA, JAXA, and the United States now fill a track that used to hold two runners. A place is really settled, Mason jokes, when you can choose the habitat with the better Martian cocktails. Culture will drift as it always does from Long Island to Wisconsin. His book notes that a Muslim on Mars would sometimes pray up into a dusty sky toward Mecca and sometimes down into 38-percent gravity, and that a second Mecca might be built. Kim Stanley Robinson already imagined a Martian religion. Meaning, Fridman says, changes when Earth is no longer the only ground that works.

Commercial flight is "a gold rush" Mason likes. His lab has worked with SpaceX medical teams on Inspiration4 and the Polaris missions, profiling Jared Isaacman and crewmates as deeply as Kelly. A three-day free-flyer to 590 kilometers — higher than the ISS or Hubble — stressed the body, then it came back. Isaacman asked if they had gotten cooked. Mason told him they could go back in the microwave. Skin biopsies before and after Inspiration4, never done before, mapped macrophages creeping toward the surface and explained some of the rashes. Commercial astronauts now volunteer blood, urine, tears, semen. "Every one of your cells is worthy of study" is the creepy geneticist email Mason sends back.

Fridman wants to record a podcast in orbit and had assumed that was 10 or 20 years out. Mason's guess for Elon Musk is around 2026: short, already-demonstrated Dragon free-flyers, not a months-long ISS stay. Musk has said he will not fly until it is responsible, given how many companies depend on him. For scientists, NASA money still comes with a congressional promise not to work with anyone in China, a rule Mason does not face on NIH or NSF grants and finds sad because it blocks the backhanded compliments scientists use to compete in the same room. China is building its own station. By 2028 there may be four stations on orbit, including Orbital Reef and work from Lockheed Martin. Axiom is furthest along.

Axiom Space is assembling the first private station: a module hoped for 2024, berthed to ISS, then detached around 2028. Axiom 1 was the first all-private crew to dock, four people, about 10 days, nearly 80 experiments. Axiom 2 has named John Shoffner and veteran NASA astronaut Peggy Whitson; they have already trained on genomics in Mason's Cornell lab. Public figures put Axiom 1 near $55 million. A proposed 550-day "to Mars and back" twin flight sits in a $50–100 million band depending on how much science defrays the stay. Someone on X posted about $35,000 a night on ISS; Mason said that sounded about right. At $10,000 per kilogram, mass is still the tyrant.

The first experimental constraint is a floating drop in someone's eye. Liquids and solids need toxicity testing; harsh reagents go into a glove box with triple containment. Fly a machine and you build four: one to fly, three to destroy in shatter, fire, and vibration tests that mimic launch. Mason's group, with Kate Rubins, Aaron Burton, and Sarah Castro-Wallace, put the first DNA sequencer on station that way. A proposed human-embryo-development study is, he says, the most controversial idea in the lab: nobody knows whether a human embryo divides well in zero-g, and finding out would mean sacrificing embryos. Sperm, by contrast, is easy to collect. For Axiom 2 they want astronauts to extract, sequence, and call viruses in flight — herpes often reactivates in orbit — rather than wait for a freezer in Houston. So far the robots have not followed. Each one would have to survive the same destructive gauntlet, so the work stays mostly manual, on a station whose CO2 scrubbers hum too loudly for easy sleep.

At the end of 500 years Mason wants a launch toward another solar system, made thinkable by the exoplanet boom that barely existed in 1989. Before that hop he lingers on Titan: Saturn's green-hued moon, methane lakes you might swim in, hydrocarbons for fuel, cold enough to hurt. Microbial life is possible. Jupiter's Io is fire to Titan's ice, but Jupiter throws radiation back out; Europa and Enceladus hide ocean under ice. Asteroids such as Ceres or Eros offer a little gravity and rare-earth metals. The 1967 Outer Space Treaty bars militarizing or owning the sky, yet mining resources without claiming the rock is legal. You can eat the orange, Mason says, and leave the peel, and still start a war over the juice.

Casualties from war have fallen over a century even as weapons got more destructive; Russia and Ukraine, as they spoke in 2022, sat in that ugly middle. Then comes the line Fridman loves: launch toward the second sun. Without antimatter miracles or hibernation that actually works, the nonfiction path is a generation ship — perhaps 20 generations living and dying on one craft aimed at the nearest known habitable exoplanet. After 500 years he thinks biology and engineering could support it. The mental-health problem is the real one. Would the tenth generation feel like the vanguard of the species, or mutiny and turn around?

His answer is that we already live on Spaceship Earth. Planetary liberty is mostly a slogan; everyone you love will die here; the difference is scale, not type. Constraints, Fridman adds, are how minds make beauty, and a door you can close is a surprisingly complete definition of freedom. A tablet can now hold every film and symphony; a crew far from Earth would start making its own shows. Quarantine years taught that people need a good connection, a walk, a game. Recreation is not a luxury on a prison that is also a gift.

Chlorohumans are Mason's far-future sketch: chloroplasts embedded in skin so you can lie in the light and eat sunshine. Full daily energy in an hour would take about two tennis courts of skin, or a smaller wing-like spread if you stayed out longer. A lamp at the right wavelength could feed the organelles far from any star. Moving a plant organelle into an animal cell sounds absurd until you remember mitochondria — bacteria our cells captured and never put down. He would not wait passively for Darwin on Mars. The book calls it directed evolution: sequence the people who adapt on one world, beam the changes to another, and run a virtuous cycle of comparison. Bacteria will always be cheaper experimental subjects, and they are already evolving on the station.

Scott Kelly's T cells learned peptides from ISS bugs you do not meet on Earth. He came home with new hitchhikers in skin, mouth, and stool. The station's ecosystem is 20 years old; Mason jokes there must be Chuck Norris bacteria up there. The Extreme Microbiome Project chases the rest of that logic into salt, fire, and cold. Lake Hillier in Australia is bubblegum pink from carotenoid-making organisms, including *Dunaliella*, that want about 30 percent salt and die below 10 or 15. Walking in feels like the brine is lysing the cells on your feet. A pilot emailed that the lake had paled; they told him to wait, the bloom would come back.

Strains of *Acinetobacter pittii* pulled from the station have drifted so far they no longer look Earth-like; Mason's group and Kasthuri Venkateswaran at JPL have found bacteria and fungi that are, in effect, new species born in orbit. They named one fungus after a Cornell donor. Samples from Turkmenistan's Darvaza gas crater — the "lake of fire" left when a Soviet rig collapsed — and from Brooklyn's Gowanus Canal yield tough *Pseudomonas* that eat toxins. Create a poisonous landscape, Mason says, and evolution answers with biochemistry that can later remediate other Superfund sites. That is the roadmap he wants for human cells and for the microbiomes we will take with us.

Where will the interstellar breakthroughs come from — physics, biology, or information? Mason, true to form, says all of the above, then lingers on AI companions. It would be a colossal failure, he thinks, if the people writing the code did not embed duty, caretaking, friendship, and creativity. Fridman asks him to steel-man HAL 9000. Mason grants that HAL did what it was programmed to do, and coins "deontogenic" for a genetic sense of duty. A human, he hopes, would have looked for a third spacecraft instead of treating crew as expendable. Stuart Russell's self-doubt in machines is one patch; Mason would query a parliament of other AIs at moments of uncertainty, knowing parliaments also deadlock. Treating a system as a servant, Fridman adds, debases the user — which is why children are told to be polite to Alexa.

On physics he wants wormholes he cannot yet build, antimatter drives starved of antimatter, and, more plausibly, fusion propulsion — always 10 years away, maybe not after a few centuries. Electromagnetic shielding could become a literal force field against cosmic rays. Uploading a mind into Kurzweil's cloud would be a kind of immortality, but he is not sure it would still be the self you have in flesh. His longevity company, Onegevity, is about living better and maybe to 150, which he finds reasonable. People who tell him they will not die should, he says, plan on being wrong. Immortality would rewrite the social contract. Mortality, as he argued with the entropy goggles, is liberty.

Fridman likes the thought of clones: a reasonable copy of you, even a crappy one, would probably satisfy the people who love you, which is a hard test of why the original matters. Maybe ideas are the organism and bodies are meat vehicles. Mason points to Derek Parfit's *Reasons and Persons*: you are partly the memories other people hold. If everyone forgot you, you would be, in a sense, deceased. Swap 40 percent of your neurons and the relationships may still be doing more of the defining than the tissue. His next book, *The Age of Prediction*, written with the same donor the fungus was named for, is about machine learning that picks cancer drugs, ages blood at a crime scene, and, more darkly, the Facebook "social contagion" experiments around 2012 and 2016. IBM Watson walked into a room of doctors and talked about replacing them. Mason thinks pathology imaging is already better as AI, and should be, but that HAL-like certainty without self-doubt is a poor model of a physician.

Advice to the Padawans: this is empirically the best day for discovery that has yet happened, and tomorrow will have more data still, which is exactly why choosing is terrifying. Find the thing that keeps you up at night. Mason describes being woken by someone inside his skull knocking to get out — how to engineer a cell against radiation, a paper that returns a week later as a method. Be pleasantly haunted. You may spend five or ten years in jobs you do not love, or 15 in school, before reputation lets you do the work. Be patient and impatient at once. Silence the short dopamine enough for the longer flame to become a fire, then add variety so a PhD does not shrink you: Counter-Strike, Diablo, or sunrise rooftop dancing in New York before lab.

A childhood friend died by suicide when Mason was about 11. He did not yet understand mental illness; after the grief he told his wife that if it ever looks as if he hanged himself, she should look for a killer. He has since learned that some suffering is so great that euthanasia can be a real exit, and he does not confuse that with his own vow. The darker private weather was ordinary heartbreak, the sense that a chest had been relocated, which later, via Neruda and Gibran, became a trench that could hold more joy. He will even schedule a day of underpriced whiskey and rain. Rick Rubin warned him not to get addicted to the sadness because it can feel more real than fleeting happiness. He is not afraid of dying. That, he says, would be like being afraid of sunrise.

From age 17 he has felt he had already had enough of life not to feel cheated — a low bar then, a fuller one now that the genetic dreams of that teenager run in a Cornell lab and predictive tools gave his grandfather two years instead of two months with metastatic cancer. The NASA Twins Study began with a no from John Charles: Mason offered to profile astronauts with money he already had, and the program was not ready. No, he decided, means no for now if you still believe the idea. He would like to go to ISS or deep space later, when a death would be less traumatic for his daughter, and he would consider a one-way trip to Mars. Dying there, looking back at the planet he was born on, would not make him sad. "It'd be an honor."

Why are we here? "To serve as the guardians of life itself." Leverage the frailty of life into the ability to protect it — humans, other species, AIs, and lives that will not look like us. If this is the only universe, we are shepherds because there is no second chance. He would accept being replaced by kinder, smarter machines if they carried an echo of that duty, and not if they were gray goo. The book ends with the possibility of baby universes. Fridman closes with Stanisław Lem in *Solaris*: man has gone out to explore other worlds without exploring his own labyrinth. Mason would like the last breath to be on that red neighbor anyway, or at least in space, which is already pretty good.