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  • richardmitnick 4:19 pm on March 8, 2017 Permalink | Reply
    Tags: Harvard Physics, , ozy.com, , Sabrina Pasterski,   

    From MIT and Harvard via ozy.com: Women in Stem “This Millennial Might Be the New Einstein” Sabrina Pasterski 

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    JAN 12 2016
    Farah Halime

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    Sabrina Pasterski

    Her research could change our understanding of the fundamentals as we know them.

    One of the things the brilliant minds at MIT do — besides ponder the nature of the universe and build sci-fi gizmos, of course — is notarize aircraft airworthiness for the federal government. So when Sabrina Pasterski walked into the campus offices one cold January morning seeking the OK for a single-engine plane she had built, it might have been business as usual. Except that the shaggy-haired, wide-eyed plane builder before them was just 14 and had already flown solo. “I couldn’t believe it,” recalls Peggy Udden, an executive secretary at MIT, “not only because she was so young, but a girl.”

    OK, it’s 2016, and gifted females are not exactly rare at MIT; nearly half the undergrads are women. But something about Pasterski led Udden not just to help get her plane approved, but to get the attention of the university’s top professors. Now, eight years later, the lanky, 22-year-old Pasterski is already an MIT graduate and Harvard Ph.D. candidate who has the world of physics abuzz. She’s exploring some of the most challenging and complex issues in physics, much as Stephen Hawking and Albert Einstein (whose theory of relativity just turned 100 years old) did early in their careers. Her research delves into black holes, the nature of gravity and spacetime. A particular focus is trying to better understand “quantum gravity,” which seeks to explain the phenomenon of gravity within the context of quantum mechanics. Discoveries in that area could dramatically change our understanding of the workings of the universe.

    She’s also caught the attention of some of America’s brightest working at NASA. Also? Jeff Bezos, founder of Amazon.com and aerospace developer and manufacturer Blue Origin, who’s promised her a job whenever she’s ready. Asked by e-mail recently whether his offer still stands, Bezos told OZY: “God, yes!”

    But unless you’re the kind of rabid physics fan who’s seen her papers on semiclassical Virasoro symmetry of the quantum gravity S-matrix and Low’s subleading soft theorem as a symmetry of QED (both on approaches to understanding the shape of space and gravity and the first two papers she ever authored), you may not have heard of Pasterski. A first-generation Cuban-American born and bred in the suburbs of Chicago, she’s not on Facebook, LinkedIn or Instagram and doesn’t own a smartphone. She does, however, regularly update a no-frills website called PhysicsGirl, which features a long catalog of achievements and proficiencies. Among them: “spotting elegance within the chaos.”

    Pasterski stands out among a growing number of newly minted physics grads in the U.S. There were 7,329 in 2013, double the four-decade low of 3,178 in 1999, according to the American Institute of Physics. Nima Arkani-Hamed, a Princeton professor and winner of the inaugural $3 million Fundamental Physics Prize, told OZY he’s heard “terrific things” about Pasterski from her adviser, Harvard professor Andrew Strominger, who is about to publish a paper with physics rock star Hawking. She’s also received hundreds of thousands of dollars in grants from the Hertz Foundation, the Smith Foundation and the National Science Foundation.

    Pasterski, who speaks in frenetic bursts, says she has always been drawn to challenging what’s possible. “Years of pushing the bounds of what I could achieve led me to physics,” she says from her dorm room at Harvard. Yet she doesn’t make it sound like work at all: She calls physics “elegant” but also full of “utility.”

    Despite her impressive résumé, MIT wait-listed Pasterski when she first applied. Professors Allen Haggerty and Earll Murman were aghast. Thanks to Udden, the pair had seen a video of Pasterski building her airplane. “Our mouths were hanging open after we looked at it,” Haggerty said. “Her potential is off the charts.” The two went to bat for her, and she was ultimately accepted, later graduating with a grade average of 5.00, the school’s highest score possible.

    An only child, Pasterski speaks with some awkwardness and punctuates her e-mails with smiley faces and exclamation marks. She says she has a handful of close friends but has never had a boyfriend, an alcoholic drink or a cigarette. Pasterski says: “I’d rather stay alert, and hopefully I’m known for what I do and not what I don’t do.”

    While mentors offer predictions of physics fame, Pasterski appears well grounded. “A theorist saying he will figure out something in particular over a long time frame almost guarantees that he will not do it,” she says. And Bezos’s pledge notwithstanding, the big picture for science grads in the U.S. is challenging: The U.S. Census Bureau’s most recent American Community Survey shows that only about 26 percent of science grads in the U.S. had jobs in their chosen fields, while nearly 30 percent of physics and chemistry post-docs are unemployed. Pasterski seems unperturbed. “Physics itself is exciting enough,” she says. ”It’s not like a 9-to-5 thing. When you’re tired you sleep, and when you’re not, you do physics.”
    ________________________________________________________________________________________________________________________________________
    Sabrina Gonzalez Pasterski (born June 3, 1993) is an American physicist from Chicago, Illinois who studies string theory and high energy physics. She describes herself as “a proud first-generation Cuban-American & Chicago Public Schools alumna.” She completed her undergraduate studies at the Massachusetts Institute of Technology (MIT) and is currently a graduate student at Harvard University.

    Pasterski has made contributions in the field of gravitational memories.[9] She is best known for her concept of “the Triangle,” which connects several physical ideas.

    Pasterski was born in Chicago on June 3, 1993. She enrolled at the Edison Regional Gifted Center in 1998, and graduated from the Illinois Mathematics and Science Academy in 2010.[10]

    Pasterski holds an active interest in aviation. She took her first flying lesson in 2003, co-piloted FAA1 at EAA AirVenture Oshkosh in 2005 and started building a kit aircraft by 2006. She soloed her Cessna 150 in Canada in 2007 and certified the aircraft she had built from a kit as airworthy in 2008, with MIT’s assistance.[citation needed] Her first U.S. solo flight was in that kit aircraft in 2009 after being signed off by her CFI Jay Maynard.[citation needed]

    Pasterski’s scientific heroes include Leon Lederman, Dudley Herschbach, and Freeman Dyson, and she was drawn to physics by Jeff Bezos. She has received job offers from Blue Origin, an aerospace company founded by Amazon.com’s Jeff Bezos, and the National Aeronautics and Space Administration (NASA).

    Before focusing on high energy theory, Pasterski worked on the CMS experiment at the Large Hadron Collider. At 21, Pasterski spoke at Harvard about her concepts of “the Triangle” and “Spin Memory”, and completed “the Triangle” for EM during an invited talk at MIT’s Center for Theoretical Physics. This work has formed the basis for further work, with one 2015 paper describing it as “a recently discovered universal triangle connecting soft theorems, symmetries and memory in gauge and gravitational theories. At 22, she spoke at a Harvard Faculty Conference about whether or not those concepts should be applied to black hole hair and discussed her new method for detecting gravitational waves.

    In early 2016, a paper by Stephen Hawking, Malcolm J. Perry, and Andrew Strominger (Pasterski’s doctoral advisor of whom she was working independently at the time) titled “Soft Hair on Black Holes” cited Pasterski’s work, making hers the only one of twelve single-author papers referenced that was authored by a female scientist.[non-primary source needed] This resulted in extensive media coverage after its appearance on the arXiv and in the days leading up to it.

    Shortly after the 2016 Hawking paper was released, actor George Takei referenced Pasterski on his Twitter account with her quote, “‘Hopefully I’m known for what I do and not what I don’t do.’ A poignant sentiment.” The Steven P. Jobs Trust article included in the tweet has been shared over 527,000 times.

    International coverage of the paper and Pasterski’s work subsequently appeared in Russia Today, Poland’s Angora newspaper and DNES in the Czech Republic. In 2016, rapper Chris Brown posted a page with a video promoting Pasterski. Forbes and The History Channel ran stories about Pasterski for their audiences in Mexico and Latin America respectively. People en Español, one of the most widely read Spanish language magazines, featured Pasterski in their April 2016 print edition. [Wikipedia]

    See the full article here .

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    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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    The Department of Physics at Harvard is large and diverse. With 10 Nobel Prize winners (see above) to its credit, the distinguished faculty of today engages in teaching and research that spans the discipline and defines its borders, and as a result Harvard is consistently one of the top-ranked physics departments in the nation.

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  • richardmitnick 10:55 pm on December 23, 2016 Permalink | Reply
    Tags: 2017 Breakthrough Prizes, Andrew Strominger, Cumrun Vafa, Harvard Physics   

    From Harvard: “Recognition for their discoveries” 

    Harvard Physics

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    December 21, 2016
    Peter Reuell

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    Harvard’s Cumrun Vafa, the Donner Professor of Science, and Andrew Strominger, the Gwill E. York Professor of Physics, have been named winners of the 2017 Breakthrough Prize in Fundamental Physics in recognition of their groundbreaking work in a number of areas, including black hole theory, quantum gravity, and string theory.

    “It is a great pleasure to have my work recognized by such an esteemed group of colleagues,” Vafa said of the prize. “I have had the good fortune to be at Harvard for over 30 years now, and I have had the privilege of discussing physics and mathematics with my first-rate colleagues as well as talented students here. They, as well as the welcoming atmosphere at Harvard, have played a key role in my research.”

    Strominger also pointed to the community of researchers he has collaborated with over his career, and expressed hope that others will continue to seek out answers to the fundamental questions of the universe.

    “There is a prevalent myth in science — perhaps especially in theoretical physics — that the real progress is made by lone geniuses in patent offices or under apple trees, while the rest of the community merely fills in the details,” he said. “The truth is in fact just the opposite. We all help and communicate with one another on many conscious and unconscious levels, and the real progress is made by the community of seekers as a whole.

    “The physical truths about our universe are there waiting to be discovered,” he continued. “Those few who are recognized with prizes were merely the first to arrive — days, weeks, or at most a few years ahead of the others already well on their way. The selected prize winners have no irreplaceable role in the greater communal quest.”

    Vafa also credited at least part of his work to the many influential Persian scientists and mathematicians who came before him.

    “I was born in Iran, the home of many eminent scientists and mathematicians,” he said in accepting the award. “In my pursuit of science, I was inspired by their legacy. I view science as a timeless, borderless adventure where everyone can participate, and it can bring out the best in humanity. This recognition is a pleasant contrast to times like ours where the value of science is sometimes challenged and the possibility of collaborations among people coming from different countries is put to question. I am fortunate to have worked alongside over 150 first-rate physicists and mathematicians from all over the world, and I view this award as a recognition of their work as much as mine. The support of my family, and in particular my wonderful wife Afarin has played a crucial role for me. Also my three sons, Farzan ’15, Keyon ’16, and Neekon ’19 have given me much inspiration and joy throughout the years.”

    Both Vafa and Strominger have made critical contributions to the search for truths, particularly in the area of string theory.

    One of the most promising candidates for uniting the four fundamental forces — electromagnetism, gravity, and the strong and weak nuclear forces — string theory suggests that all particles actually consist of tiny, vibrating strings. Differences in those vibrations correspond to different particles, just as different vibrations of a guitar string correspond to different musical notes.

    Working together, Vafa and Strominger in 1995 made the first controlled calculation of black hole entropy — first theorized by Stephen Hawking and Jacob Bekenstein — using string theory, and demonstrating the connections between geometry and field theories that arise from string theory.

    Vafa and Strominger shared the $3 million award with Joseph Polchinski from the University of California.

    In addition, Harvard Physics Professor Xi Yin was among the recipients of the New Horizons in Physics Prize, which recognizes the work of early career physicists and mathematicians.

    Stephen J. Elledge, the Gregor Mendel Professor of Genetics and Medicine at Harvard Medical School and a Howard Hughes Medical Institute investigator, was also among the recipients of this year’s prize in the life sciences.

    Created in 2012 by Sergey Brin and Anne Wojcicki, Mark Zuckerberg and Priscilla Chan, and Yuri and Julia Milner to recognize paradigm-shifting research in a number of fields, the Breakthrough Prizes are intended to celebrate the achievements of the world’s top scientists and inspire the next generation of research.

    See the full article here .

    The Department of Physics at Harvard is large and diverse. With 10 Nobel Prize winners (see above) to its credit, the distinguished faculty of today engages in teaching and research that spans the discipline and defines its borders, and as a result Harvard is consistently one of the top-ranked physics departments in the nation.

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  • richardmitnick 4:10 pm on August 11, 2016 Permalink | Reply
    Tags: , , Harvard Physics, Lisa Randall,   

    From Harvard Physics: Women in Science – “Tips for aspiring scientists from one woman who is — literally — figuring out how the universe works” Lisa Randall 

    Harvard Physics

    Harvard Physics

    August 11, 2016
    Nicole Wetsman

    Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of.

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    Lisa Randall is a theoretical particle physicist.
    Credit: Rose Lincoln/Harvard

    Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe; the second concerned the possibility of a warped additional dimension of space.

    When she’s not unraveling cosmic mysteries as a professor in the department of physics at Harvard University, she writes popular science books. Her most recent is Dark Matter and the Dinosaurs.

    We caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists.

    When did you first know that you wanted to pursue science as a career?
    Lisa Randall: It came in stages. When I was in high school, I started thinking more seriously about physics. It didn’t even seem like a possibility before that. And then when I was in college, I decided to see how it would go, and it went well. I guess it was really when I did a postdoctoral fellowship at Berkeley, and when I did some important work and was applying for faculty jobs, I realized that’s what I was going to be doing. I probably knew sooner than I admitted.

    Why physics?
    I liked doing mathematical-type things, and I wanted to do something that had applications to the real world, something with lasting value. Even though we do things that seem abstract, we like to think they have consequences and explain things in the world.

    What’s it like to study things that you can’t necessarily see?
    Well, they’re just as real — just because you can’t see them doesn’t mean they don’t exist. All observations can be thought of as indirect, and as long as they’re reliable and reproducible, we trust what’s going on. In some ways, it’s more exciting to go beyond the things that everyone else sees, and try to understand what underlies them.

    You’ve written a number of popular science books. How did writing those books change the way you thought about your work, or the way you approached your research?
    I probably do tend to take a step back a little bit more and appreciate the big picture and what it can mean. When you’re doing research, you tend to get caught up in it, so sometimes it’s nice to sit back and think about the implications of it.

    What are the benefits of being a well-known scientist?
    One of the things is that you get more opportunities to talk to people in other fields. And it’s rewarding to think that what you do is valuable and that people want to hear about it, and to give them the opportunity to learn more about it.

    What would you consider the biggest setback in your career?
    I try to move on when something doesn’t work. So I don’t know if there was one particular thing I would say was a huge setback, scientifically, at least.

    Who inspires you?
    I don’t know if this is true for everyone, but really, it’s the science that inspires me. It isn’t exactly people per se, which sounds kind of crazy. But just reading papers and thinking some work was really great — that’s inspirational.

    If you could work with any scientist, living or dead, who would it be and why?
    I don’t really know that I have a good answer to that question, but one person I would like to meet would be [Dutch astronomer] Jan Oort. I would like to see how he thinks. He made a lot of different and important contributions to astronomy, and it’s impressive how often his name came up. And it turns out he also was a really good person.

    What advice would you give to an aspiring physicist?
    Basically to figure out what you enjoy, what your talents are, and what you’re most curious to learn about. To have the confidence to think that you can move forward, but not so much confidence that you don’t think you have to learn and catch up. You want to value your own ideas, but you want to value all of the other ideas that came before you. There’s no real shortcut. But in the end, it’s extremely worthwhile when you’re the one making interesting connections.

    Why is studying physics important?
    Because we move knowledge forward. Understanding deep fundamental things — just think about how much it changes the way we view ourselves in the world. It might not be important to each individual, but for humanity, it’s very important.

    See the full article here .

    The Department of Physics at Harvard is large and diverse. With 10 Nobel Prize winners (see above) to its credit, the distinguished faculty of today engages in teaching and research that spans the discipline and defines its borders, and as a result Harvard is consistently one of the top-ranked physics departments in the nation.

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  • richardmitnick 10:10 am on December 11, 2014 Permalink | Reply
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    From Harvard Physics via Harvard Gazette: “Eyes on Orion” 

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    Harvard Physics

    Harvard Gazette

    December 9, 2014
    Alvin Powell

    Astrophysicist looks beyond test flight to asteroids and Mars

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    Photos (1) courtesy of Bill Ingalls/NASA; (2) by Kris Snibbe/Harvard Staff Photographer

    NASA’s Orion (photo 1) is considered to be the next-generation spaceship. “Apollo was: ‘Let’s get someone to the moon and back alive.’ Orion is: ‘Let’s develop the infrastructure and the capability to gad about the solar system and have a spacecraft that can operate for months, have a spacecraft that can have a bigger safety margin than Apollo did.'” said Jonathan McDowell (photo 2), a scientist with the Harvard-Smithsonian Center for Astrophysics.

    On Friday, NASA successfully launched its next-generation spaceship farther than any astronaut has flown since the Apollo program of the 1960s. Though the Orion was unmanned during the test flight, which took it 15 times higher than the Space Station orbits, it is designed to eventually carry a human crew on missions to the moon, to near-Earth asteroids, and even to Mars.

    Jonathan McDowell, a scientist with the Harvard-Smithsonian Center for Astrophysics, works on the Chandra X-ray Observatory and also publishes Jonathan’s Space Report, a Web newsletter that focuses on launches of all kinds, manned and unmanned. He answered questions from the Gazette on the test flight, the goals of the Orion effort, and the rationale behind mounting a mission to a near-Earth asteroid.

    GAZETTE: I’ve heard this launch mentioned as the beginning of a new era. Do you think that’s true?

    McDOWELL: In a small way. I do think it’s part of a shift back in human space exploration. I say human space exploration, because the robotic space exploration program — both the scientific program in Earth orbit typified by Hubble and Chandra, and the robot probes into space, with the Mars rovers, Cassini, and so on — those have been going like gangbusters and been super-successful.

    NASA Chandra Telescope
    Chandra

    NASA Hubble Telescope
    Hubble

    NASA Mars Curiosity
    Curiosity

    NASA Cassini Spacecraft
    Cassini

    So, it’s really the American human spaceflight program that has been perhaps faltering, partly due to problems with the way NASA approached things, and partly due to political indecisiveness.

    GAZETTE: Even though computerization and technology have advanced very rapidly since, it seems we’re still catching up to Apollo and, with Orion, we’ve taken a baby step.

    McDOWELL: The Orion spacecraft is a lot more sophisticated than Apollo. It’s bigger, can carry more people. Once they build the service module, which they haven’t done yet, it will have solar panels, it will be able to last longer. Apollo was: “Let’s get someone to the moon and back alive.” Orion is: “Let’s develop the infrastructure and the capability to gad about the solar system and have a spacecraft that can operate for months, have a spacecraft that can have a bigger safety margin than Apollo did.”

    NASA Orion Spacecraft
    Orion

    It’s just amazing that we didn’t lose an Apollo mission in space. Apollo 13 was a close thing. Those folks were really brave. One can hope that there’s just a little more margin in Orion in terms of life-support systems. We have a little more understanding now after decades of operating the shuttle. In every year of the shuttle program, we launched more people into Earth orbit than in the entire Mercury-Gemini-Apollo programs combined. And so just the number of astronaut flight hours that we’ve had and even astronaut rocket propulsion minutes — getting to orbit and back — is so much bigger than we had with Apollo. So there’s a maturity with the processes now.

    This is something that can get to the moon like Apollo could get to the moon, just as your 2014 Honda Civic can get you to the grocery store much like the Model T could have done. But there’s still a big difference between them.

    That’s one aspect of this. The thing that we’re still missing is a good cheap way to get to space. And we’re limited. Orion is a compromise, because even this enormous SLS [space launch system] booster that they’re planning to get Orion to the moon can’t carry as much mass as you’d like. They’re going to various extremes to cut the weight to the bone.

    You have to have these immensely expensive SLS rockets that are still not as big as you’d like. Many people hope that the development that Space X is doing with their Falcon series of rockets will lead to something more affordable.

    GAZETTE: Is that because the SLS wasn’t designed anew? It uses off-the-shelf shuttle boosters in its rocket?

    McDOWELL: There’s some of that, yes, and it’s designed both using existing technology and with the existing processes and approaches, sort of the old NASA way. I think there’s starting to be an awareness, even in the SLS program, [that they have] to tweak that and see what they can do to make it more affordable.

    But there are constraints: “You can build it anywhere you want, as long as the jobs go to Alabama or Utah.” It’s very much influenced by political considerations of who gets the contract. “What’s the best way to get us to Mars?” is not necessarily the first constraint.

    GAZETTE: Can you address the idea of Orion visiting a near-Earth asteroid before any trip to Mars?

    McDOWELL: There are a number of reasons to be interested in near-Earth asteroids. Everyone knows there are these rocks between Mars and Jupiter called the asteroid belt. But there are also a smaller number of objects that are from maybe 10 miles across at the biggest, down to a few yards across. And these things litter the inner solar system.

    Most of them, over the billions of years of the solar system, have been soaked up by the planets, making big craters. That’s why the moon is covered by these big round holes. But there’s still a few left, and there’s some concern they might make a few more holes.

    One reason for being concerned with asteroids is the danger of them hitting us. Another reason is that some of them have heavy deposits of valuable minerals, like rare earth elements, and you might want to mine them. And a third scientific reason is that they may be relatively unchanged from the early solar system and give us insight into how the Earth itself formed.

    But I think those reasons don’t matter [because] the point of sending astronauts to an asteroid is that we need practice getting around the solar system. What we want to do in the long run is colonize the solar system. We want to live in the “Star Trek” future where Earth is not the only place where humans live. And to get there we need to be able to get around the solar system and, beyond the moon, the easiest things to get to are asteroids.

    It’s going to take a voyage of years to get to Mars [and] if anything goes wrong, you’re in big trouble, because you’re a long way from home. With asteroids, you’re maybe weeks to months to get there. So it’s longer than the three days to the moon, but it’s still a much more manageable trip time.

    GAZETTE: Is there a point at which you will be disappointed if this vehicle hasn’t taken us to Mars? Or is Mars sort of a reach goal?

    McDOWELL: Personally, I think Mars is a reach goal for Orion. I don’t think that NASA has a budgetarily realistic plan to get to Mars in the foreseeable future. But I think if we keep tweaking things and [start doing] what we haven’t been doing, [which] is investing in advanced technology development, we may be able to improve the rockets and the systems enough to get something practical to Mars.

    GAZETTE: They’re talking about Mars in the 2040s. That seems like a long way away.

    McDOWELL: It’s not a definite plan, but it’s hard to see it happening any earlier than the 2030s and it’s easy to see it slipping to the 2050s, but not much beyond that. So I would say that’s sort of the right timeframe to imagine a human Mars expedition, if we don’t somehow lose interest in human space exploration.

    GAZETTE: Do we have the technology to go now, if the budgetary and political will was there?

    McDOWELL: I think we’re not far off. You know, one of the great things we’re discovering on the space station is how often things break. There’s this oxygen-regeneration system and the urine-recycling system and things like that which had unexpected “failure modes” that they were able to fix with [help from] cargo ships. You can’t do that if you’re halfway to Mars when the thing breaks.

    You need to build your Mars ship and operate it in Earth orbit for a few years — operate several of them — to get experience in how they break, until you’re confident that you can send one out to Mars on a long trip without too much breaking down on the way.

    I think we’re starting to understand that there’s all this research you have to do. We don’t really know, right now, how to land a big enough vehicle on Mars. Mars is a hard place to land because the atmosphere is too thin for parachutes to really do the job, and too thick to just use rocket engines on the way down. So you have to use a mix of methods, and it’s complicated. The heavier vehicle you have, the harder it is to get it right.

    So there’s some basic technology that we still [have] got to develop and we’re a ways off from being able to do the Mars mission. [We’re] not so far from being able to do a Phobos mission, which is one of the moons of Mars. Getting down into Mars’ gravity well and back up is what’s really hard. If you can make the long duration vehicle work OK, maybe you can go to Phobos and back just to say you’ve been there.

    See the full article here.

    The Department of Physics at Harvard is large and diverse. With 10 Nobel Prize winners (see above) to its credit, the distinguished faculty of today engages in teaching and research that spans the discipline and defines its borders, and as a result Harvard is consistently one of the top-ranked physics departments in the nation.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

     
  • richardmitnick 6:17 pm on December 7, 2014 Permalink | Reply
    Tags: , , Harvard Physics, ,   

    From Harvard: “The ever-smaller future of physics” 

    Harvard University

    Harvard University

    December 5, 2014
    Alvin Powell

    If physicists want to find their long-sought “theory of everything,” they have to get small. And Nobel Prize-winning theoretical physicist Steven Weinberg thinks he knows roughly how small.

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    Nobel winner Steven Weinberg brought his thoughts on a “theory of everything” to the Physics Department’s Lee Historical Lecture. Jon Chase/Harvard Staff Photographer

    Weinberg, who spoke at a packed Geological Lecture Hall Monday evening, said there are hints that the answers to fundamental questions will reveal themselves at around a million billionths — between 10­-17 and 10-19 — of the radius of the typical atomic nucleus.

    “It is in that range that we expect to find really new physics,” said Weinberg, a onetime Harvard professor now on the faculty at the University of Texas at Austin.

    Physicists understand that there are four fundamental forces of nature. Two are familiar in our everyday lives: those of gravity and electromagnetism. The two less-familiar forces operate at the atomic level. The strong force holds the nucleus together while the weak force is responsible for the radioactive decay that changes one type of particle to another and the nuclear fusion that powers the sun.

    For decades, physicists have toiled to create a single theory that explains how all four of these forces work, but without success, instead settling on one theory that explains how gravity acts on a macro scale and another to describe the other three forces and their interactions at the atomic level.

    Weinberg, who won the 1979 Nobel Prize in Physics, with Sheldon Glashow and Abdus Salam, for electroweak theory explaining how the weak force and electromagnetism are related, returned to Harvard to deliver the Physics Department’s annual David M. Lee Historical Lecture. He was introduced by department chair Masahiro Morii and by Andrew Strominger, the Gwill E. York Professor of Physics, who recalled taking Weinberg’s class on general relativity as a Harvard undergrad.

    “I wish I could say I remembered you in Physics 210,” Weinberg said to laughs as he took the podium.

    The event also recognized the outstanding work of four graduate students — two in experimental physics, Dennis Huang and Siyuan Sun, and two in theoretical physics, Shu-Heng Shao and Bo Liu — with the Gertrude and Maurice Goldhaber Prize.

    Weinberg pointed to several hints of something significant going on at the far extremes of tininess. One hint is that the strong force, which weakens at shorter scales, and the weak and electromagnetic forces, which get stronger across shorter distances, appear to converge at that scale.

    Gravity is so weak that it isn’t felt at the atomic scale, overpowered by the other forces that operate there. However, Weinberg said, if you calculate how much mass two protons or two electrons would need for gravity to balance their repulsive electrical force, it would have to not just be enormous, but on a similar scale as the other measurements, the equivalent of 1.04 x 1018 gigaelectron volts.

    “There is a strong suggestion that gravity is somehow unified with those other forces at these scales,” Weinberg said.

    Weinberg also said there are experimental hints in the extremely small masses of neutrinos and in possible proton decay that the tiniest scales are significant in ways that are fundamental to physics.

    “This is a very crude estimate, but the mass of neutrinos which are being observed are in the same ballpark that you would expect from new physics associated with a fundamental length,” Weinberg said. “It all seems to hang together.”

    A major challenge for physicists is that the energy needed to probe what is actually going on at the smallest levels is far beyond current technology, something like 10 trillion times the highest energy we can harness now. And new technology to explore the problem experimentally is not on the horizon. Even with all the wealth in the world, scientists wouldn’t know where to begin, Weinberg said.

    But the experiment may have already been done, by nature, and there may be a way to look back at it, Weinberg said. During the inflationary period immediately after the Big Bang there was that kind of energy, he said, and it would be evident as gravitation waves in the cosmic microwave background, an echo of the Big Bang that astronomers study for hints of the early universe. In fact, astronomers announced they had found such waves earlier this year, though they are waiting for confirmation of the results.

    Gravitational Wave Background
    gravitational waves

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    “The big question that we face … is, can we find a truly fundamental theory uniting all the forces, including gravitation … characterized by tiny lengths like 10-17 to 10-19 nuclear radii?” Weinberg said. “Is it a string theory? That seems like the most beautiful candidate, but we don’t have any direct evidence that it is a string theory. The only handle we have … on this to do further experiments is in cosmology.”

    See the full article here.

    Harvard is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best known landmark.

    Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

    Please help promote STEM in your local schools.

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  • richardmitnick 7:35 am on August 14, 2014 Permalink | Reply
    Tags: , Harvard Physics, NMR,   

    From physicsworld.com: “Going mobile with NMR spectroscopy” 

    physicsworld
    physicsworld.com

    Aug 13, 2014
    Gabriel Popkin

    Nuclear magnetic resonance (NMR) spectroscopy could be about to go mobile, thanks to a team of researchers in the US that has shrunk the electronic components needed for the spectroscopic technique down to fit on an integrated circuit the size of a grain of sand. The team’s chip, combined with compact, state-of-the-art magnets, could lead to portable devices that can help identify chemicals in lab reactions and on industrial production lines.

    nmr
    Mini me: the miniaturized NMR chip

    NMR spectroscopy, a technology that has helped visualize the chemical structures of countless compounds, allows scientists to gather information from the spins – the inherent magnetic moments – of atomic nuclei. When compounds with certain nuclei, like those of hydrogen or the isotope carbon-13, are placed in a strong magnetic field, the nuclear spins align with or against the magnetic field. If the nuclei are then bombarded with electromagnetic radiation at a frequency determined by the magnetic-field strength, the directions of the nuclear spins will precess. It is then possible to measure the precession frequencies of the spins of nuclei in a sample to determine how a molecule’s atoms are arranged.

    Mini spectroscopy

    While scientists have used NMR spectroscopy since the 1950s, the necessary hardware has typically been bulky, requiring superconducting magnets larger than a person and electronics the size of a kitchen cabinet. Recently, smaller permanent magnets that are good enough for NMR have come on to the market and some of the electronic components have been integrated onto semiconductor chips, which has enabled table-top systems that can probe small molecules. But a miniaturized integrated system with a full range of NMR spectroscopy capabilities had not been developed.

    Now, though, a team based at Harvard University has done just that. The researchers placed a radio-frequency (RF) transmitter and receiver along with a component known as an “arbitrary pulse sequencer” onto a silicon chip with a surface area of 4 mm2. The scientists then combined their chip with a cube-shaped magnet around the size of a large grapefruit and were able to analyse a variety of compounds. To do the analyses, samples are placed inside a small hole in the centre of the magnet.

    The key advance was miniaturizing and integrating the pulse sequencer, which controls the timing, shapes and amplitudes of the RF pulses directed at the sample being measured, says Donhee Ham, the Harvard physicist who led the research. “The arbitrary pulse sequencer is the brain of the entire chip,” he says.

    Multidimensional probes

    The electronics the team developed are an improvement on those of previous portable systems, which have so far only implemented simplified NMR techniques that cannot fully resolve complex molecular structures, says Ham. The more sophisticated technique of “multidimensional” NMR spectroscopy can be extremely useful when trying to probe structures beyond the most basic molecules. With the new integrated pulse sequencer, the researchers can “control the RF transmitter in any way we desire, so the transmitter can produce any RF pulse sequence”, according to Ham – a requirement for multidimensional NMR spectroscopy.

    In addition to enabling portable spectroscopy, the team’s miniaturized electronics could be coupled with larger magnets to greatly speed up the NMR process. By incorporating dozens of the chips into a large superconducting magnet, researchers could scan many samples at once rather than one at a time, which can be a laborious process. Such a “high throughput” spectroscopy scheme could accelerate drug discovery, Ham says.

    The team’s work “represents a further step towards the complete miniaturization of an NMR spectrometer”, says Giovanni Boero of the Swiss Federal Institute of Technology in Lausanne. But Boero says that the integration of the pulse sequencer is a technical advance rather than a game changer. “It is not a revolutionary paper, but it is an important work in the frame of the worldwide effort towards the goal of performing NMR spectroscopy using a low-cost, highly portable system.”

    The work is published in the Proceedings of the National Academy of Sciences.

    See the full article here.

    PhysicsWorld is a publication of the Institute of Physics. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

    We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
    IOP Institute of Physics

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