adactio / tags / astrophysics

Tagged with “astrophysics” (10)

  1. Start The Week: The health of science

    Tom Sutcliffe with Sir Robert Lechler, Jo Dunkley, Bernie Bulkin and Elizabeth Pisani.

    There is nothing new for chemistry to discover, says Bernie Bulkin. In Solving Chemistry: A Scientist’s Journey, the former Head of Science at BP argues that an unprecedented event has happened: a branch of science has made all the major discoveries it is likely to make. He tells Tom Sutcliffe what this means for chemistry - and for science more broadly.

    Medicine is in the midst of ‘a biomedical revolution’ says Professor Sir Robert Lechler. His own field of kidney transplants has been transformed by our new understanding of the immune system. He has helped to curate Spare Parts, an exhibition at the Science Gallery that poses the question: how many transplants could we have before we were no longer ourselves?

    Elizabeth Pisani has watched interest in different diseases rise and fall. As an epidemiologist she charts the impact that press attention and public grants have on medical research, with some becoming fashionable while in others treatments lag behind. And she warns that scientists too often fail to take account of the human context when delivering medicines.

    Astrophysicist Jo Dunkley assesses our understanding of the universe in a concise new guide. But the universe is 85% dark matter - and we still know very little about this. She draws attention to the brilliant female scientists who contributed to breakthroughs in physics, but whose contributions have been forgotten along the way.

    https://www.bbc.co.uk/programmes/m00026ws

    —Huffduffed by adactio

  2. Sara Seager: Other Earths. Other Life. - The Long Now

    We are one tool away from learning which distant planets already have life on them and which might be welcoming to life.

    MIT Planetary Scientist Sara Seager is working on the tool. She is chair of the NASA team developing a “Starshade” that would allow a relatively rudimentary space telescope to observe Earth-size planets directly, which would yield atmospheric analysis, which would determine a planet’s life-worthiness.

    Despite 1,000-plus exoplanet discoveries by the Kepler spacecraft and the hundreds more expected from the Transiting Exoplanet Survey Satellite after 2017, neither instrument can make detailed observation of the atmosphere of small rocky planets, because each star’s brilliance overwhelms direct study of the rocky motes that might harbor life. A Starshade cures that.

    A former MacArthur Fellow, Seager is author of Exoplanet Atmospheres (02010) and an astrophysics professor at MIT. Her maxim: “For exoplanets, anything is possible under the laws of physics and chemistry.”

    http://longnow.org/seminars/02015/aug/10/other-earths-other-life/

    —Huffduffed by adactio

  3. What’s Wrong With the Science of “Interstellar”? | Mother Jones

    Paramount Pictures and Warner Bros. PicturesIn the new sci-fi epic Interstellar, Matthew McConaughey and Anne Hathaway don astronaut suits, leave an Earth that has been so poisoned it can no longer produce food to support the human race, and zip through a wormhole in search of new planets where homo sapiens might be able start over—while Jessica Chastain works on a mathematical formula that will allow our species to defy gravity. The big-budget blockbuster is a familiar gotta-save-humanity cinematic romp, chock-full of dramatic chills and special effects thrills. But Interstellar, directed by Batman movie-maker Chris Nolan, also attempts to attain a certain gravitas by taking seriously the science invoked within the film. After all, Kip Thorne, one of the world’s leading theoretical physicists and experts on relativity, was an executive producer and consultant for the movie. And Neil DeGrasse Tyson has praised the flick for featuring scientific principles "as no other feature film has shown." But one of our planet’s top astrobiologists has a somewhat different view.

    I took David Grinspoon, who holds the chair of astrobiology at the Library of Congress, to the Washington, DC, premiere of Interstellar—a posh event held at the Smithsonian Air and Space Museum and attended by pundits, scientists, and aerospace firm officials and lobbyists. Afterward, he and I recorded an episode of the Inquiring Minds podcast focused on the science and themes of this grand film.

    Grinspoon, a 2006 winner of the Carl Sagan Medal, advises NASA on planetary exploration and is involved with the Venus Express spacecraft and the Curiosity Rover on Mars. He is a widely-recognized expert on the possibility of life beyond Earth. He runs a funky website and is working on a book about the anthropocene—the somewhat controversial notion that the Earth is in a geologic epoch being shaped by human activity. And a few years ago, he attended a meeting of scientists called together by the makers of Interstellar—back when Steven Spielberg was slated to direct the film—to kick around the scientific ideas presented in the movie. That is, Grinspoon was the perfect date for this movie.

    So, I asked him, what was it like to be present at creation? Grinspoon recalled:

    There was a meeting of the minds that a bunch of us were invited to…on the Caltech campus. It was really fun. They had some astronomers, astrobiologists, psychologists…They presented the very basic premise of the film and asked us to brainstorm on some of the themes, and they recorded the whole thing. Spielberg showed up, and he brought his dad…It was a very wide-ranging discussion…What I remember of the treatment that we saw at that time…it had some of the same themes of getting to other planets and using black holes. But that was kind of it. It didn’t have the plot yet…If memory serves me, the original story actually had [theoretical physicist and cosmologist Stephen] Hawking as a character in the film, who was going to be sent into orbit. Experiencing weightlessness is something that helped him with his disability…I don’t know how much of this I’m conflating now. It’s been a few years. But I think there was even a love interest.

    Stephen Hawking playing Stephen Hawking in love in outer space? "Exactly," Grinspoon said. "Those themes of love and space are still in the final movie"—even though Hawking isn’t.

    But back to the science: Do wormholes, which defy conventional physics and our down-to-earth notion of time, exist? Can they be stellar shortcuts used to get from one end of the universe to the other in a flash? And can they be created by sentient beings, as the movie suggests? Well, maybe, Grinspoon said, but there’s at least one big problem with using a wormhole for transportation:

    It’s sort of pushing the edge of what is scientifically possible. It helps solve a problem. There is a big problem, if you’re going to have any kind of a fictional plot involving travel to other stars. If you do it with normal physics, it’s going to take hundreds of years. Who has the time for a movie that long? That’s the whole thing with Star Trek. We had warp drive.

    "You’d end up ripping apart everything that went into the wormhole," says Grinspoon. "It’s not like NASA is actually working on this."

    Wormhole is sort of the modern version of warp drive. And, yeah, there are actually solutions to Einstein’s general relativity that produce these structures that have been called wormholes, where the geometry of space-time connects different places that in normal space are very distant in the universe. In theory, you can do that. The problem is, if you actually look at how that might work, it doesn’t really work. You’d end up ripping apart everything that went into the wormhole. It’s not like NASA is actually working on this. It’s a way to have your plot device fit the science.

    In the movie, a scientist explains how a wormhole could make distant space exploration possible by placing a point at the top of a piece of paper and drawing a line to a point at the bottom. The bottom point, we are told, is very, very, very far from the top. Think galaxies apart. He then folds the paper in half so the points line up and punches a hole in the paper through both points. That hole is a wormhole. Is this, I asked Grinspoon, a scientifically accurate reflection of how space-time can bend?

    I loved that scene. That’s exactly how a physicist would explain a wormhole…That is exactly how Kip Thorne would describe a wormhole, and he is the guy who came up with wormholes…That scene was great from a scientific point of view. That’s exactly how a physicist would explain it.

    So the movie does take the science seriously? Well, Grinspoon says, not always:

    Yes and no. Here I’m balancing my inner snob and my delight that people are interested in a movie on themes that I love. But there is a critique I can’t help but apply to this. The science is spotty. It’s interesting they had Kip Thorne involved. They paid a lot of attention to relativity and space-time. And yet there’s this whole other theme about what happens to the planet, what happens to the Earth, and these other planets. They go and find planets and there are conditions on them [not consistent with science]. The planetary parts of the film, I thought, were really weak. That’s my bailiwick.

    "The planetary parts of the film, I thought, were really weak," says Grinspoon. "There are aspects to the planets they get to which…don’t make sense from basic physics.

    For instance, they describe this ecological disaster on Earth. I like the fact they are talking about that and raising consciousness. It’s clear that it’s climate change and we screwed up the Earth…That’s a good theme. But the specific things they say about it—they say there’s this blight [attacking all crops] that’s building up the nitrogen [in the atmosphere] and that’s going to draw down the oxygen. Anybody who knows about planetary atmosphere is going to sit there at that point and go, "That’s a bunch of BS." It’s not that that ruins the movie for most people. But why couldn’t they have run that by somebody? It wouldn’t change the plot…There are aspects to the planets they get to which also don’t make sense from basic physics. There’s a planet with ice clouds…That’s BS…Something like that would fall. Because of gravity! Is that so crucial to the plot? There’s a planet around a black hole…Some physicists might quibble whether that’s even possible or stable. But one obvious problem is, when they landed there it was daylight. But there’s no sun and a black hole doesn’t put out light. So where is the light coming from?

    Is this being too picky? The filmmakers do try hard to show there is science underlying the seemingly impossible journey made. Yet at the end, several knotty plot dilemmas are resolved when—the most mild spoiler alert!—a character enters a black hole and is somehow able to communicate with others back on Earth and in the past. So, I put it to Grinspoon, is this science or…magic?

    It’s on the fine line between science and magic…If you were at a cocktail party with a few physicists who had a few drinks, which I’ve been to, this is the kind of thing that comes up. And somebody said, "Name a subject that’s really on the edge between science and magic," somebody will say, "Time travel through black holes." You can find some equation when it sort of, maybe works. But, then, of course, if you have time travel, it introduces all these horrible paradoxes. What if you went back and told your mother not to marry your father?…In the movie I found it suspiciously close to magic. That was one thing that bothered me. It was kind of like they needed to tie up the plot: and, then there’s a black hole, and magical things happen, so everything is fine.

    The ending was tough to figure. Can you really have a five-dimensional system manifested in a three-dimensional manner that allows someone to go back in time to the precise place he or she needs to be to save humanity? I confessed to Grinspoon that I was confused.

    I kind of liked that aspect. I sort of like the fact that you are confused by that. Reality on that level is confusing. One of the weird things about modern physics is that we do find there are apparently these other dimensions that we don’t directly experience that explain some aspects of the overall geometry and reality of our universe. When you encounter the real physics of that stuff, you do get this feeling you are having now of going, "Well, that’s confusing, how could that be?" I’m not sure about the specific realism of how that was depicted. But I do like the idea that there’s a movie that is going to get people thinking, "Really? There could be other dimensions?" That is evoking something that people have when they encounter modern physics.

    At first glance, Interstellar does seem to have a green message, warning that climate change could make the world uninhabitable for humans (and, presumably, other species). Yet there’s an odd twist. The tag line for the film is, "The end of the Earth will not be the end of us." And the lead scientist, played by Michael Caine (no longer Alfred the Butler), says at one point: "We are not meant to save the world. We are meant to leave it." In other words, if humans do trash the planet, don’t worry, some super-smart folks will help us make a nice get-away somewhere else in this swell and expanding universe. Given that Grinspoon researches life and planetary development, I wondered what he thought of this cut-and-run theme.

    That tagline…is problematical. The reality is the opposite. It’s quite possible that the end of us will not be the end of the Earth. Even if we really screw things up and things go badly for us and our civilization, the Earth is pretty resilient. The current species here will have a mass extinction, but life will not extinguish and the Earth will recover and go on…We’re more fragile than life. And then there’s the moral implication: It doesn’t really matter, there are other planets out there, the heck with this one. I found that bothersome. Of course, in the very long run, if we are successful in getting through our current little problems of being a technological civilization, and we last for thousands, even millions and billions of years, ultimately the Earth and the sun will run their course. So if we become one of those super-wise beings that are implied in this film that make wormholes, at some point we will have to deal with the problem of moving.

    That’s in the long run. The very long run.

    http://www.motherjones.com/media/2014/11/interstellar-movie-science-david-grinspoon-inquiring-minds

    —Huffduffed by adactio

  4. The 100 Year Starship

    Dr. Mae Jemison was the first black woman in space. Now, she’s leading a wildly ambitious project: to achieve interstellar travel in the next 100 years. She’s with us.

    Think Star Trek and you won’t be far off. A new Pentagon project is putting out seed money for interstellar travel. Humans, rambling around among the stars. It’s called the 100 Year Starship project. It’s as wildly ambitious as just about anything you can imagine.

    The spaceship, its energy source, its passengers’ survival – full-blown or just as DNA… all giant challenges. Not to mention that we’re sort of broke and not even flying space shuttles right now. Leader of the new effort: astronaut Mae Jemison, the first black woman in space. She’s with us.

    This hour, On Point: the 100 Year Starship.

    —Huffduffed by adactio

  5. David Deutsch And The Beginning of Infinity

    Quantum computing genius and Oxford don David Deutsch is a thinker of such scale and audaciousness he can take your breath away. His bottom line is simple and breathtaking all at once.

    It’s this: human beings are the most important entities in the universe. Or as Deutsch might have it, in the “multiverse.” For eons, little changed on this planet, he says. Progress was a joke. But once we got the Enlightenment and the scientific revolution, our powers of inquiry and discovery became infinite. Without limit.

    —Huffduffed by adactio

  6. Lord Martin Rees: Life and the Cosmos

    It’s famously called the Final Frontier, and thanks to rapidly developing technology we now know more about the outer reaches of our galaxy than ever. But that leaves unknowns.

    Does the universe have any limits? Are there any other earth-like planets out there? And the big one, are we alone?

    Addressing the University of Melbourne recently, Britain’s Astronomer Royal, Lord Martin Rees, reports on the latest research.

    http://fora.tv/2010/03/30/Lord_Martin_Rees_Life_and_the_Cosmos

    —Huffduffed by adactio

  7. Avoiding Armageddon: Diverting Asteroids with Nuclear Explosives

    Every couple of years, the earth is hit by a body with energy near that of the Hiroshima bomb. Deposited high in the atmosphere these events causes little or no damage. On longer timescales, impacts occur with the potential to destroy regions, or whole civilizations. Learn about the impact threat, followed by a systematic development of the requirements to divert such an object.

    http://uctv.tv/search-details.aspx?showID=17643

    —Huffduffed by adactio