 |
In this infrared image, stellar winds from a giant star cause interstellar dust to form ripples. There's a whole lot of dust—which contains oxygen, carbon, iron, nickel, and all the other elements—out there, and eventually some of it finds its way into our bodies. Photograph by NASA, JPL-Caltech |
We have stardust in us as old as the universe—and some that may have landed on Earth just a hundred years ago.
Excerpt from National Geographic
By Simon Worrall
Astrophysics and medical pathology don't, at first sight, appear to have much in common. What do sunspots have to do with liver spots? How does the big bang connect with cystic fibrosis?
Book jacket courtesy of schrijver+schrijver
Astrophysicist Karel Schrijver, a senior fellow at the Lockheed Martin Solar and Astrophysics Laboratory, and his wife, Iris Schrijver, professor of pathology at Stanford University, have joined the dots in a new book, Living With the Stars: How the Human Body Is Connected to the Life Cycles of the Earth, the Planets, and the Stars.
Talking from their home in Palo Alto, California, they explain how everything in us originated in cosmic explosions billions of years ago, how our bodies are in a constant state of decay and regeneration, and why singer Joni Mitchell was right.
"We are stardust," Joni Mitchell famously sang in "Woodstock." It turns out she was right, wasn't she?
Iris: Was she ever! Everything we are and everything in the universe and on Earth originated from stardust, and it continually floats through us even today. It directly connects us to the universe, rebuilding our bodies over and again over our lifetimes.
That was one of the biggest surprises for us in this book. We really didn't realize how impermanent we are, and that our bodies are made of remnants of stars and massive explosions in the galaxies. All the material in our bodies originates with that residual stardust, and it finds its way into plants, and from there into the nutrients that we need for everything we do—think, move, grow. And every few years the bulk of our bodies are newly created.
Can you give me some examples of how stardust formed us?
Karel: When the universe started, there was just hydrogen and a little helium and very little of anything else. Helium is not in our bodies. Hydrogen is, but that's not the bulk of our weight. Stars are like nuclear reactors. They take a fuel and convert it to something else. Hydrogen is formed into helium, and helium is built into carbon, nitrogen and oxygen, iron and sulfur—everything we're made of. When stars get to the end of their lives, they swell up and fall together again, throwing off their outer layers. If a star is heavy enough, it will explode in a supernova.
So most of the material that we're made of comes out of dying stars, or stars that died in explosions. And those stellar explosions continue. We have stuff in us as old as the universe, and then some stuff that landed here maybe only a hundred years ago. And all of that mixes in our bodies.
Stars are being born and stars are dying in this infrared snapshot of the heavens. You and I—we come from stardust.
Photograph by NASA, JPL-Caltech, University of Wisconsin
Your book yokes together two seemingly different sciences: astrophysics and human biology. Describe your individual professions and how you combined them to create this book.
Iris: I'm a physician specializing in genetics and pathology. Pathologists are the medical specialists who diagnose diseases and their causes. We also study the responses of the body to such diseases and to the treatment given. I do this at the level of the DNA, so at Stanford University I direct the diagnostic molecular pathology laboratory. I also provide patient care by diagnosing inherited diseases and also cancers, and by following therapy responses in those cancer patients based on changes that we can detect in their DNA.
Our book is based on many conversations that Karel and I had, in which we talked to each other about topics from our daily professional lives. Those areas are quite different. I look at the code of life. He's an astrophysicist who explores the secrets of the stars. But the more we followed up on our questions to each other, the more we discovered our fields have a lot more connections than we thought possible.
Karel: I'm an astrophysicist. Astrophysicists specialize in all sorts of things, from dark matter to galaxies. I picked stars because they fascinated me. But no matter how many stars you look at, you can never see any detail. They're all tiny points in the sky.
So I turned my attention to the sun, which is the only star where we can see what happens all over the universe. At some point NASA asked me to lead a summer school for beginning researchers to try to create materials to understand the things that go all the way from the sun to the Earth. I learned so many things about these connections I started to tell Iris. At some point I thought: This could be an interesting story, and it dawned on us that together we go all the way, as she said, from the smallest to the largest. And we have great fun doing this together.
We tend to think of our bodies changing only slowly once we reach adulthood. So I was fascinated to discover that, in fact, we're changing all the time and constantly rebuilding ourselves. Talk about our skin.
Iris: Most people don't even think of the skin as an organ. In fact, it's our largest one. To keep alive, our cells have to divide and grow. We're aware of that because we see children grow. But cells also age and eventually die, and the skin is a great example of this.
It's something that touches everything around us. It's also very exposed to damage and needs to constantly regenerate. It weighs around eight pounds [four kilograms] and is composed of several layers. These layers age quickly, especially the outer layer, the dermis. The cells there are replaced roughly every month or two. That means we lose approximately 30,000 cells every minute throughout our lives, and our entire external surface layer is replaced about once a year.
Very little of our physical bodies lasts for more than a few years. Of course, that's at odds with how we perceive ourselves when we look into the mirror. But we're not fixed at all. We're more like a pattern or a process. And it was the transience of the body and the flow of energy and matter needed to counter that impermanence that led us to explore our interconnectedness with the universe.
You have a fascinating discussion about age. Describe how different parts of the human body age at different speeds.
Iris: Every tissue recreates itself, but they all do it at a different rate. We know through carbon dating that cells in the adult human body have an average age of seven to ten years. That's far less than the age of the average human, but there are remarkable differences in these ages. Some cells literally exist for a few days. Those are the ones that touch the surface. The skin is a great example, but also the surfaces of our lungs and the digestive tract. The muscle cells of the heart, an organ we consider to be very permanent, typically continue to function for more than a decade. But if you look at a person who's 50, about half of their heart cells will have been replaced.
Our bodies are never static. We're dynamic beings, and we have to be dynamic to remain alive. This is not just true for us humans. It's true for all living things.
A figure that jumped out at me is that 40,000 tons of cosmic dust fall on Earth every year. Where does it all come from? How does it affect us?
Karel: When the solar system formed, it started to freeze gas into ice and dust particles. They would grow and grow by colliding. Eventually gravity pulled them together to form planets. The planets are like big vacuum cleaners, sucking in everything around them. But they didn't complete the job. There's still an awful lot of dust floating around.
When we say that as an astronomer, we can mean anything from objects weighing micrograms, which you wouldn't even see unless you had a microscope, to things that weigh many tons, like comets. All that stuff is still there, being pulled around by the gravity of the planets and the sun. The Earth can't avoid running into this debris, so that dust falls onto the Earth all the time and has from the very beginning. It's why the planet was made in the first place.
Nowadays, you don't even notice it. But eventually all that stuff, which contains oxygen and carbon, iron, nickel, and all the other elements, finds its way into our bodies.
When a really big piece of dust, like a giant comet or asteroid, falls onto the Earth, you get a massive explosion, which is one of the reasons we believe the dinosaurs became extinct some 70 million years ago. That fortunately doesn't happen very often. But things fall out of the sky all the time. [Laughs]
Many everyday commodities we use also began their existence in outer space. Tell us about salt.
Karel: Whatever you mention, its history began in outer space. Take salt. What we usually mean by salt is kitchen salt. It has two chemicals, sodium and chloride. Where did they come from? They were formed inside stars that exploded billions of years ago and at some point found their way onto the Earth. Stellar explosions are still going on today in the galaxy, so some of the chlorine we're eating in salt was made only recently.
You study pathology, Iris. Is physical malfunction part of the cosmic order?
Iris: Absolutely. There are healthy processes, such as growth, for which we need cell division. Then there are processes when things go wrong. We age because we lose the balance between cell deaths and regeneration. That's what we see in the mirror when we age over time. That's also what we see when diseases develop, such as cancers. Cancer is basically a mistake in the DNA, and because of that the whole system can be derailed. Aging and cancer are actually very similar processes. They both originate in the fact that there's a loss of balance between regeneration and cell loss.
Cystic fibrosis is an inherited genetic disease. You inherit an error in the DNA. Because of that, certain tissues do not have the capability to provide their normal function to the body. My work is focused on finding changes in DNA in different populations so we can understand better what kinds of mutations are the basis of that disease. Based on that, we can provide prognosis. There are now drugs that target specific mutations, as well as transplants, so these patients can have a much better life span than was possible 10 or 20 years ago.
How has writing this book changed your view of life—and your view of each other?
Karel: There are two things that struck me, one that I had no idea about. The first is what Iris described earlier—the impermanence of our bodies. As a physicist, I thought the body was built early on, that it would grow and be stable. Iris showed me, over a long series of dinner discussions, that that's not the way it works. Cells die and rebuild all the time. We're literally not what were a few years ago, and not just because of the way we think. Everything around us does this. Nature is not outside us. We are nature.
As far as our relationship is concerned, I always had a great deal of respect for Iris, and physicians in general. They have to know things that I couldn't possibly remember. And that's only grown with time.
Iris: Physics was not my favorite topic in high school. [Laughs] Through Karel and our conversations, I feel that the universe and the world around us has become much more accessible. That was our goal with the book as well. We wanted it to be accessible and understandable for anyone with a high school education. It was a challenge to write it that way, to explain things to each other in lay terms. But it has certainly changed my view of life. It's increased my sense of wonder and appreciation of life.
In terms of Karel's profession and our relationship, it has inevitably deepened. We understand much better what the other person is doing in the sandboxes we respectively play in. [Laughs]
The Future of Technology in 2015?
Excerpt from
cnet.com
The year gone by brought us more robots, worries about artificial intelligence, and difficult lessons on space travel. The big question: where's it all taking us?
Every year, we capture a little bit more of the future -- and yet the future insists on staying ever out of reach.
Consider space travel. Humans have been traveling beyond the atmosphere for more than 50 years now -- but aside from a few overnights on the moon four decades ago, we have yet to venture beyond low Earth orbit.
Or robots. They help build our cars and clean our kitchen floors, but no one would mistake a Kuka or a Roomba for the replicants in "Blade Runner." Siri, Cortana and Alexa, meanwhile, are bringing some personality to the gadgets in our pockets and our houses. Still, that's a long way from HAL or that lad David from the movie "A.I. Artificial Intelligence."
Self-driving cars? Still in low gear, and carrying some bureaucratic baggage that prevents them from ditching certain technology of yesteryear, like steering wheels.
And even when these sci-fi things arrive, will we embrace them? A Pew study earlier this year found that Americans are decidedly undecided. Among the poll respondents, 48 percent said they would like to take a ride in a driverless car, but 50 percent would not. And only 3 percent said they would like to own one.
"Despite their general optimism about the long-term impact of technological change," Aaron Smith of the Pew Research Center wrote in the report, "Americans express significant reservations about some of these potentially short-term developments" such as US airspace being opened to personal drones, robot caregivers for the elderly or wearable or implantable computing devices that would feed them information.
Let's take a look at how much of the future we grasped in 2014 and what we could gain in 2015.
Space travel: 'Space flight is hard'
In 2014, earthlings scored an unprecedented achievement in space exploration when the European Space Agency landed a spacecraft on a speeding comet, with the potential to learn more about the origins of life. No, Bruce Willis wasn't aboard. Nobody was. But when the 220-pound Philae lander, carried to its destination by the Rosetta orbiter, touched down on comet 67P/Churyumov-Gerasimenko on November 12, some 300 million miles from Earth, the celebration was well-earned.A shadow quickly fell on the jubilation, however. Philae could not stick its first landing, bouncing into a darker corner of the comet where its solar panels would not receive enough sunlight to charge the lander's batteries. After two days and just a handful of initial readings sent home, it shut down. For good? Backers have allowed for a ray of hope as the comet passes closer to the sun in 2015. "I think within the team there is no doubt that [Philae] will wake up," lead lander scientist Jean-Pierre Bibring said in December. "And the question is OK, in what shape? My suspicion is we'll be in good shape."
The trip for NASA's New Horizons spacecraft has been much longer: 3 billion miles, all the way to Pluto and the edge of the solar system. Almost nine years after it left Earth, New Horizons in early December came out of hibernation to begin its mission: to explore "a new class of planets we've never seen, in a place we've never been before," said project scientist Hal Weaver. In January, it will begin taking photos and readings of Pluto, and by mid-July, when it swoops closest to Pluto, it will have sent back detailed information about the dwarf planet and its moon, en route to even deeper space.
Also in December, NASA made a first test spaceflight of its Orion capsule on a quick morning jaunt out and back, to just over 3,600 miles above Earth (or approximately 15 times higher than the International Space Station). The distance was trivial compared to those those traveled by Rosetta and New Horizons, and crewed missions won't begin till 2021, but the ambitions are great -- in the 2030s, Orion is expected to carry humans to Mars.
In late March 2015, two humans will head to the ISS to take up residence for a full year, in what would be a record sleepover in orbit. "If a mission to Mars is going to take a three-year round trip," said NASA astronaut Scott Kelly, who will be joined in the effort by Russia's Mikhail Kornienko, "we need to know better how our body and our physiology performs over durations longer than what we've previously on the space station investigated, which is six months."
There were more sobering moments, too, in 2014. In October, Virgin Galactic's sleek, experimental SpaceShipTwo, designed to carry deep-pocketed tourists into space, crashed in the Mojave Desert during a test flight, killing one test pilot and injuring the other. Virgin founder Richard Branson had hoped his vessel would make its first commercial flight by the end of this year or in early 2015, and what comes next remains to be seen. Branson, though, expressed optimism: "Space flight is hard -- but worth it," he said in a blog post shortly after the crash, and in a press conference, he vowed "We'll learn from this, and move forward together." Virgin Galactic could begin testing its next spaceship as soon as early 2015.
The crash of SpaceShipTwo came just a few days after the explosion of an Orbital Sciences rocket lofting an unmanned spacecraft with supplies bound for the International Space Station. And in July, Elon Musk's SpaceX had suffered the loss of one of its Falcon 9 rockets during a test flight. Musk intoned, via Twitter, that "rockets are tricky..."
Still, it was on the whole a good year for SpaceX. In May, it unveiled its first manned spacecraft, the Dragon V2, intended for trips to and from the space station, and in September, it won a $2.6 billion contract from NASA to become one of the first private companies (the other being Boeing) to ferry astronauts to the ISS, beginning as early as 2017. Oh, and SpaceX also has plans to launch microsatellites to establish low-cost Internet service around the globe, saying in November to expect an announcement about that in two to three months -- that is, early in 2015.
One more thing to watch for next year: another launch of the super-secret X-37B space place to do whatever it does during its marathon trips into orbit. The third spaceflight of an X-37B -- a robotic vehicle that, at 29 feet in length, looks like a miniature space shuttle -- ended in October after an astonishing 22 months circling the Earth, conducting "on-orbit experiments."
Self-driving cars: Asleep at what wheel?
Spacecraft aren't the only vehicles capable of autonomous travel -- increasingly, cars are, too. Automakers are toiling toward self-driving cars, and Elon Musk -- whose name comes up again and again when we talk about the near horizon for sci-fi tech -- says we're less than a decade away from capturing that aspect of the future. In October, speaking in his guise as founder of Tesla Motors, Musk said: "Like maybe five or six years from now I think we'll be able to achieve true autonomous driving where you could literally get in the car, go to sleep and wake up at your destination." (He also allowed that we should tack on a few years after that before government regulators give that technology their blessing.)Google has long been working on its own robo-cars, and until this year, that meant taking existing models -- a Prius here, a Lexus there -- and buckling on extraneous gear. Then in May, the tech titan took the wraps off a completely new prototype that it had built from scratch. (In December, it showed off the first fully functional prototype.) It looked rather like a cartoon car, but the real news was that there was no steering wheel, gas pedal or brake pedal -- no need for human controls when software and sensors are there to do the work.
Or not so fast. In August, California's Department of Motor Vehicles declared that Google's test vehicles will need those manual controls after all -- for safety's sake. The company agreed to comply with the state's rules, which went into effect in September, when it began testing the cars on private roads in October.
Regardless of who's making your future robo-car, the vehicle is going to have to be not just smart, but actually thoughtful. It's not enough for the car to know how far it is from nearby cars or what the road conditions are. The machine may well have to make no-win decisions, just as human drivers sometimes do in instantaneous, life-and-death emergencies. "The car is calculating a lot of consequences of its actions," Chris Gerdes, an associate professor of mechanical engineering, said at the Web Summit conference in Dublin, Ireland, in November. "Should it hit the person without a helmet? The larger car or the smaller car?"
Robots: Legging it out
So when do the robots finally become our overlords? Probably not in 2015, but there's sure to be more hand-wringing about both the machines and the artificial intelligence that could -- someday -- make them a match for homo sapiens. At the moment, the threat seems more mundane: when do we lose our jobs to a robot?The inquisitive folks at Pew took that very topic to nearly 1,900 experts, including Vint Cerf, vice president at Google; Web guru Tim Bray; Justin Reich of Harvard University's Berkman Center for Internet & Society; and Jonathan Grudin, principal researcher at Microsoft. According to the resulting report, published in August, the group was almost evenly split -- 48 percent thought it likely that, by 2025, robots and digital agents will have displaced significant numbers of blue- and white-collar workers, perhaps even to the point of breakdowns in the social order, while 52 percent "have faith that human ingenuity will create new jobs, industries, and ways to make a living, just as it has been doing since the dawn of the Industrial Revolution."
Still, for all of the startling skills that robots have acquired so far, they're often not all there yet. Here's some of what we saw from the robot world in 2014:
Teamwork: Researchers at the École Polytechnique Fédérale De Lausanne in May showed off their "Roombots," cog-like robotic balls that can join forces to, say, help a table move across a room or change its height.
A sense of balance: We don't know if Boston Dynamics' humanoid Atlas is ready to trim bonsai trees, but it has learned this much from "The Karate Kid" (the original from the 1980s) -- it can stand on cinder blocks and hold its balance in a crane stance while moving its arms up and down.
Catlike jumps: MIT's cheetah-bot gets higher marks for locomotion. Fed a new algorithm, it can run across a lawn and bound like a cat. And quietly, too. "Our robot can be silent and as efficient as animals. The only things you hear are the feet hitting the ground," MIT's Sangbae Kim, a professor of mechanical engineering, told MIT News. "This is kind of a new paradigm where we're controlling force in a highly dynamic situation. Any legged robot should be able to do this in the future."
Sign language: Toshiba's humanoid Aiko Chihira communicated in Japanese sign language at the CEATEC show in October. Her rudimentary skills, limited for the moment to simple messages such as signed greetings, are expected to blossom by 2020 into areas such as speech synthesis and speech recognition.
Dance skills: Robotic pole dancers? Tobit Software brought a pair, controllable by an Android smartphone, to the Cebit trade show in Germany in March. More lifelike was the animatronic sculpture at a gallery in New York that same month -- but what was up with that witch mask?
Emotional ambition: Eventually, we'll all have humanoid companions -- at least, that's always been one school of thought on our robotic future. One early candidate for that honor could be Pepper, from Softbank and Aldebaran Robotics, which say the 4-foot-tall Pepper is the first robot to read emotions. This emo-bot is expected to go on sale in Japan in February.
Ray guns: Ship shape
Damn the photon torpedoes, and full speed ahead. That could be the motto for the US Navy, which in 2014 deployed a prototype laser weapon -- just one -- aboard a vessel in the Persian Gulf. Through some three months of testing, the device "locked on and destroyed the targets we designated with near-instantaneous lethality," Rear Adm. Matthew L. Klunder, chief of naval research, said in a statement. Those targets were rather modest -- small objects mounted aboard a speeding small boat, a diminutive Scan Eagle unmanned aerial vehicle, and so on -- but the point was made: the laser weapon, operated by a controller like those used for video games, held up well, even in adverse conditions.Artificial intelligence: Danger, Will Robinson?
What happens when robots and other smart machines can not only do, but also think? Will they appreciate us for all our quirky human high and low points, and learn to live with us? Or do they take a hard look at a species that's run its course and either turn us into natural resources, "Matrix"-style, or rain down destruction?Musk himself more than once in 2014 invoked the likes of the "Terminator" movies and the "scary outcomes" that make them such thrilling popcorn fare. Except that he sees a potentially scary reality evolving. In an interview with CNBC in June, he spoke of his investment in AI-minded companies like Vicarious and Deep Mind, saying: "I like to just keep an eye on what's going on with artificial intelligence. I think there is potentially a dangerous outcome."
He has put his anxieties into some particularly colorful phrases. In August, for instance, Musk tweeted that AI is "potentially more dangerous than nukes." And in October, he said this at a symposium at MIT: "With artificial intelligence, we are summoning the demon. ... You know all those stories where there's the guy with the pentagram and the holy water and he's like... yeah, he's sure he can control the demon, [but] it doesn't work out."
Musk has a kindred spirit in Stephen Hawking. The physicist allowed in May that AI could be the "biggest event in human history," and not necessarily in a good way. A month later, he was telling John Oliver, on HBO's "Last Week Tonight," that "artificial intelligence could be a real danger in the not too distant future." How so? "It could design improvements to itself and outsmart us all."
But Google's Eric Schmidt, is having none of that pessimism. At a summit on innovation in December, the executive chairman of the far-thinking tech titan -- which in October teamed up with Oxford University to speed up research on artificial intelligence -- said that while our worries may be natural, "they're also misguided."