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  • richardmitnick 1:33 pm on August 11, 2018 Permalink | Reply
    Tags: , , , , , Quasars are now known to be supermassive black holes feeding on surrounding gas not stars., , WIRED, Zwicky Transit Facility at California’s Palomar Observatory   

    From Wired: “Star-Swallowing Black Holes Reveal Secrets in Exotic Light Shows” 

    Wired logo

    From Wired

    08.11.18
    Joshua Sokol

    Black holes, befitting their name and general vibe, are hard to find and harder to study. You can eavesdrop on small ones from the gravitational waves that echo through space when they collide—but that technique is new, and still rare. You can produce laborious maps of stars flitting around the black hole at the center of the Milky Way or nearby galaxies. Or you can watch them gulp down gas clouds, which emit radiation as they fall.

    Now researchers have a new option. They’ve begun corralling ultrabright flashes called tidal disruption events (TDEs), which occur when a large black hole seizes a passing star, shreds it in two and devours much of it with the appetite of a bear snagging a salmon. “To me, it’s sort of like science fiction,” said Enrico Ramirez-Ruiz, an astrophysicist at University of California, Santa Cruz, and the Niels Bohr Institute.

    During the past few years, though, the study of TDEs has transformed from science fiction to a sleepy cottage industry, and now into something more like a bustling tech startup.

    Automated wide-field telescopes that can pan across thousands of galaxies each night have uncovered about two dozen TDEs. Included in these discoveries are some bizarre and long-sought members of the TDE zoo. In June, a study in the journal Nature described an outburst of X-ray light in a cluster of faraway stars that astronomers interpreted as a midsized black hole swallowing a star. That same month, another group announced in Science that they had discovered what may be brightest ever TDE, one that illuminated faint gas at the heart of a pair of merging galaxies.

    These discoveries have taken place as our understanding of what’s really happening during a TDE comes into sharper focus. At the end of May, a group of astrophysicists proposed [The Astrophysical Journal Letters] a new theoretical model for how TDEs work. The model can explain why different TDEs can appear to behave differently, even though the underlying physics is presumably the same.

    Astronomers hope that decoding these exotic light shows will let them conduct a black hole census. Tidal disruptions expose the masses, spins and sheer numbers of black holes in the universe, the vast majority of which would be otherwise invisible. Theorists are hungry, for example, to see if TDEs might unveil any intermediate-mass black holes with weights between the two known black hole classes: star-size black holes that weigh a few times more than the sun, and the million- and billion-solar-mass behemoths that haunt the cores of galaxies. The Nature paper claims they may already have.


    A numerical simulation of the core of a star as it’s being consumed by a black hole. Video by Guillochon and Ramirez-Ruiz

    Researchers have also started to use TDEs to probe the fundamental physics of black holes. They can be used to test whether black holes always have event horizons—curtains beyond which nothing can return—as Einstein’s theory of general relativity predicts.

    Meanwhile, many more observations are on the way. The rate of new TDEs, now about one or two per year, could jump up by an order of magnitude [Stellar Tidal Disruption Events in General Relativity]even by the end of this year because of the Zwicky Transient Facility, which started scanning the sky over California’s Palomar Observatory in March.

    Zwicky Transit Facility at California’s Palomar Observatory schematic

    Zwicky Transit Facility at California’s Palomar Observatory

    And with the addition of planned observatories, it may increase perhaps another order of magnitude in the years to come.Researchers have also started to use TDEs to probe the fundamental physics of black holes. They can be used to test whether black holes always have event horizons—curtains beyond which nothing can return—as Einstein’s theory of general relativity predicts.

    “The field has really blossomed,” said Suvi Gezari at the University of Maryland, one of the few stubborn pioneers who staked their careers on TDEs during leaner years. She now leads the Zwicky Transient Facility’s TDE-hunting team, which has already snagged unpublished candidates in its opening months, she said. “Now people are really digging in.”

    Searching for Star-Taffy

    In 1975, the British physicist Jack Hills first dreamed up a black-hole-eats-star scenario as a way to explain what powers quasars—superbright points of light from the distant universe. (Quasars are now known to be supermassive black holes feeding on surrounding gas, not stars.) But in 1988, the British cosmologist Martin Rees realized [Nature]that black holes snacking on a star would exhibit a sharp flare, not a steady glow. Looking for such flares could let astronomers find and study the black holes themselves, he argued.

    Nothing that fit the bill turned up until the late 1990s. That’s when Stefanie Komossa, at the time a graduate student at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, found massive X-ray flares [Discovery of a giant and luminous X-ray outburst from the optically inactive galaxy pair RXJ1242.6-1119] from the centers of distant galaxies that brightened and dimmed according to the Rees predictions.

    The astronomical community responded to these discoveries—based on just a few data points—with caution. Then in the mid-2000s, Gezari, then beginning a postdoc at the California Institute of Technology, searched for and discovered her own handful of TDE candidates. She looked for flashes of ultraviolet light, not X-rays as Komossa had. “In the old days,” Gezari said, “I was just trying to convince people that any of our discoveries were actually due to a tidal disruption.”

    Soon, though, she had something to sway even the doubters. In 2010, Gezari discovered an especially clear flare, rising and falling as modelers predicted. She published it in Nature in 2012, catching other astronomers’ attention. In the years since, large surveys in optical light, sifting through the sky for changes in brightness, have taken over the hunt. And like Komossa’s and Gezari’s TDEs, which had both been fished out of missions designed to look for other things, the newest batch showed up as bycatch. “It was, oh, why didn’t we think about looking for these?” said Christopher Kochanek, an astrophysicist at Ohio State University who works on a project designed to search for supernovas [ASAS-SN OSU All-Sky Automated Survey for Supernovae].

    Now, with a growing number of TDEs in hand, astrophysicists are within arm’s reach of Rees’s original goal: pinpointing and studying gargantuan black holes. But they still need to learn to interpret these events, divining their basic physics. Unexpectedly, the known TDEs fall into separate classes [A unified model for tidal disruption events]. Some seem to emit mostly ultraviolet and optical light, as if from gas heated to tens of thousands of degrees. Others glow fiercely with X-rays, suggesting temperatures an order of magnitude higher. Yet presumably they all have the same basic physical root.

    To be disrupted, an unlucky star must venture close enough to a black hole that gravitational tides exceed the internal gravity that binds the star together. In other words, the difference in the black hole’s gravitational pull on the near and far sides of the star, along with the inertial pull as the star swings around the black hole, stretches the star out into a stream. “Basically it spaghettifies,” said James Guillochon, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics.

    The outer half of the star escapes away into space. But the inner half—that dense stream of star-taffy—swirls into the black hole, heating up and releasing huge sums of energy that radiate across the universe.

    With this general mechanism understood, researchers had trouble understanding why individual TDEs can look so distinct. One longstanding idea appeals to different phases of the star-eating process. As the star flesh gets initially torn away and stretched into a stream, it might ricochet around the black hole and slam into its own tail. This process might heat the tail up to ultraviolet-producing temperatures—but not hotter. Then later—after a few months or a year—the star would settle into an accretion disk, a fat bagel of spinning gas that theories predict should be hot enough to emit X-rays.

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 2:41 pm on July 22, 2018 Permalink | Reply
    Tags: , , , , , , , , Sau Lan Wu, WIRED,   

    From LHC at CERN and University of Wisconsin Madison via WIRED and Quanta: Women in STEM “Meet the Woman Who Rocked Particle Physics—Three Times” Sau Lan Wu 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    U Wisconsin

    via

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    WIRED

    originated at

    Quanta Magazine
    Quanta Magazine

    7.22.18
    Joshua Roebke

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    Sau Lan Wu at CERN, the laboratory near Geneva that houses the Large Hadron Collider. The mural depicts the detector she and her collaborators used to discover the Higgs boson. Thi My Lien Nguyen/Quanta Magazine

    In 1963, Maria Goeppert Mayer won the Nobel Prize in physics for describing the layered, shell-like structures of atomic nuclei. No woman has won since.

    One of the many women who, in a different world, might have won the physics prize in the intervening 55 years is Sau Lan Wu. Wu is the Enrico Fermi Distinguished Professor of Physics at the University of Wisconsin, Madison, and an experimentalist at CERN, the laboratory near Geneva that houses the Large Hadron Collider.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    Wu’s name appears on more than 1,000 papers in high-energy physics, and she has contributed to a half-dozen of the most important experiments in her field over the past 50 years. She has even realized the improbable goal she set for herself as a young researcher: to make at least three major discoveries.

    Wu was an integral member of one of the two groups that observed the J/psi particle, which heralded the existence of a fourth kind of quark, now called the charm. The discovery, in 1974, was known as the November Revolution, a coup that led to the establishment of the Standard Model of particle physics.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.


    Standard Model of Particle Physics from Symmetry Magazine

    Later in the 1970s, Wu did much of the math and analysis to discern the three “jets” of energy flying away from particle collisions that signaled the existence of gluons—particles that mediate the strong force holding protons and neutrons together. This was the first observation of particles that communicate a force since scientists recognized photons of light as the carriers of electromagnetism. Wu later became one of the group leaders for the ATLAS experiment, one of the two collaborations at the Large Hadron Collider that discovered the Higgs boson in 2012, filling in the final piece of the Standard Model.

    CERN ATLAS Higgs Event


    CERN/ATLAS detector

    She continues to search for new particles that would transcend the Standard Model and push physics forward.

    Sau Lan Wu was born in occupied Hong Kong during World War II. Her mother was the sixth concubine to a wealthy businessman who abandoned them and her younger brother when Wu was a child. She grew up in abject poverty, sleeping alone in a space behind a rice shop. Her mother was illiterate, but she urged her daughter to pursue an education and become independent of volatile men.

    Wu graduated from a government school in Hong Kong and applied to 50 universities in the United States. She received a scholarship to attend Vassar College and arrived with $40 to her name.

    Although she originally intended to become an artist, she was inspired to study physics after reading a biography of Marie Curie. She worked on experiments during consecutive summers at Brookhaven National Laboratory on Long Island, and she attended graduate school at Harvard University. She was the only woman in her cohort and was barred from entering the male dormitories to join the study groups that met there. She has labored since then to make a space for everyone in physics, mentoring more than 60 men and women through their doctorates.

    Quanta Magazine joined Sau Lan Wu on a gray couch in sunny Cleveland in early June. She had just delivered an invited lecture about the discovery of gluons at a symposium to honor the 50th birthday of the Standard Model. The interview has been condensed and edited for clarity.

    2
    3
    Wu’s office at CERN is decorated with mementos and photos, including one of her and her husband, Tai Tsun Wu, a professor of theoretical physics at Harvard.
    Thi My Lien Nguyen/Quanta Magazine

    You work on the largest experiments in the world, mentor dozens of students, and travel back and forth between Madison and Geneva. What is a normal day like for you?

    Very tiring! In principle, I am full-time at CERN, but I do go to Madison fairly often. So I do travel a lot.

    How do you manage it all?

    Well, I think the key is that I am totally devoted. My husband, Tai Tsun Wu, is also a professor, in theoretical physics at Harvard. Right now, he’s working even harder than me, which is hard to imagine. He’s doing a calculation about the Higgs boson decay that is very difficult. But I encourage him to work hard, because it’s good for your mental state when you are older. That’s why I work so hard, too.

    Of all the discoveries you were involved in, do you have a favorite?

    Discovering the gluon was a fantastic time. I was just a second- or third-year assistant professor. And I was so happy. That’s because I was the baby, the youngest of all the key members of the collaboration.

    The gluon was the first force-carrying particle discovered since the photon. The W and Z bosons, which carry the weak force, were discovered a few years later, and the researchers who found them won a Nobel Prize. Why was no prize awarded for the discovery of the gluon?

    Well, you are going to have to ask the Nobel committee that. [Laughs.] I can tell you what I think, though. Only three people can win a Nobel Prize. And there were three other physicists on the experiment with me who were more senior than I was. They treated me very well. But I pushed the idea of searching for the gluon right away, and I did the calculations. I didn’t even talk to theorists. Although I married a theorist, I never really paid attention to what the theorists told me to do.

    How did you wind up being the one to do those calculations?

    If you want to be successful, you have to be fast. But you also have to be first. So I did the calculations to make sure that as soon as a new collider at at DESY [the German Electron Synchrotron] turned on in Hamburg we could see the gluon and recognize its signal of three jets of particles.

    DESY Helmholtz Centres & Networks: DESY’s synchrotron radiation source: the PETRA III storage ring (in orange) with the three experimental halls (in blue) in 2015.

    We were not so sure in those days that the signal for the gluon would be clear-cut, because the concept of jets had only been introduced a couple of years earlier, but this seemed to be the only way to discover gluons.

    You were also involved in discovering the Higgs boson, the particle in the Standard Model that gives many other particles their masses. How was that experiment different from the others that you were part of?

    I worked a lot more and a lot longer to discover the Higgs than I have on anything else. I worked for over 30 years, doing one experiment after another. I think I contributed a lot to that discovery. But the ATLAS collaboration at CERN is so large that you can’t even talk about your individual contribution. There are 3,000 people who built and worked on our experiment [including 600 scientists at Brookhaven National Lab, NY, USA]. How can anyone claim anything? In the old days, life was easier.

    Has it gotten any easier to be a woman in physics than when you started?

    Not for me. But for younger women, yes. There is a trend among funding agencies and institutions to encourage younger women, which I think is great. But for someone like me it is harder. I went through a very difficult time. And now that I am established others say: Why should we treat you any differently?

    Who were some of your mentors when you were a young researcher?

    Bjørn Wiik really helped me when I was looking for the gluon at DESY.

    How so?

    Well, when I started at the University of Wisconsin, I was looking for a new project. I was interested in doing electron-positron collisions, which could give the clearest indication of a gluon. So I went to talk to another professor at Wisconsin who did these kinds of experiments at SLAC, the lab at Stanford. But he was not interested in working with me.

    So I tried to join a project at the new electron-positron collider at DESY. I wanted to join the JADE experiment [abbreviated from the nations that developed the detector: Japan, Germany (Deutschland) and England]. I had some friends working there, so I went to Germany and I was all set to join them. But then I heard that no one had told a big professor in the group about me, so I called him up. He said, “I am not sure if I can take you, and I am going on vacation for a month. I’ll phone you when I get back.” I was really sad because I was already in Germany at DESY.

    But then I ran into Bjørn Wiik, who led a different experiment called TASSO, and he said, “What are you doing here?” I said, “I tried to join JADE, but they turned me down.” He said, “Come and talk to me.” He accepted me the very next day.

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    TASSO detector at PETRA at DESY

    And the thing is, JADE later broke their chamber, and they could not have observed the three-jet signal for gluons when we observed it first at TASSO. So I have learned that if something does not work out for you in life, something else will.

    5
    Wu and Bjørn Wiik in 1978, in the electronic control room of the TASSO experiment at the German Electron Synchrotron in Hamburg, Germany. Dr. Ulrich Kötz

    You certainly turned that negative into a positive.

    Yes. The same thing happened when I left Hong Kong to attend college in the US. I applied to 50 universities after I went through a catalog at the American consulate. I wrote in every application, “I need a full scholarship and room and board,” because I had no money. Four universities replied. Three of them turned me down. Vassar was the only American college that accepted me. And it turns out, it was the best college of all the ones I applied to.

    If you persist, something good is bound to happen. My philosophy is that you have to work hard and have good judgment. But you also have to have luck.

    I know this is an unfair question, because no one ever asks men, even though we should, but how can society inspire more women to study physics or consider it as a career?

    Well, I can only say something about my field, experimental high-energy physics. I think my field is very hard for women. I think partially it’s the problem of family.

    My husband and I did not live together for 10 years, except during the summers. And I gave up having children. When I was considering having children, it was around the time when I was up for tenure and a grant. I feared I would lose both if I got pregnant. I was less worried about actually having children than I was about walking into my department or a meeting while pregnant. So it’s very, very hard for families.

    I think it still can be.

    Yeah, but for the younger generation it’s different. Nowadays, a department looks good if it supports women. I don’t mean that departments are deliberately doing that only to look better, but they no longer actively fight against women. It’s still hard, though. Especially in experimental high-energy physics. I think there is so much traveling that it makes having a family or a life difficult. Theory is much easier.

    You have done so much to help establish the Standard Model of particle physics. What do you like about it? What do you not like?

    It’s just amazing that the Standard Model works as well as it does. I like that every time we try to search for something that is not accounted for in the Standard Model, we do not find it, because the Standard Model says we shouldn’t.

    But back in my day, there was so much that we had yet to discover and establish. The problem now is that everything fits together so beautifully and the Model is so well confirmed. That’s why I miss the time of the J/psi discovery. Nobody expected that, and nobody really had a clue what it was.

    But maybe those days of surprise aren’t over.

    We know that the Standard Model is an incomplete description of nature. It doesn’t account for gravity, the masses of neutrinos, or dark matter—the invisible substance that seems to make up six-sevenths of the universe’s mass. Do you have a favorite idea for what lies beyond the Standard Model?

    Well, right now I am searching for the particles that make up dark matter. The only thing is, I am committed to working at the Large Hadron Collider at CERN. But a collider may or may not be the best place to look for dark matter. It’s out there in the galaxies, but we don’t see it here on Earth.

    Still, I am going to try. If dark matter has any interactions with the known particles, it can be produced via collisions at the LHC. But weakly interacting dark matter would not leave a visible signature in our detector at ATLAS, so we have to intuit its existence from what we actually see. Right now, I am concentrating on finding hints of dark matter in the form of missing energy and momentum in a collision that produces a single Higgs boson.

    What else have you been working on?What else have you been working on?

    Our most important task is to understand the properties of the Higgs boson, which is a completely new kind of particle. The Higgs is more symmetric than any other particle we know about; it’s the first particle that we have discovered without any spin. My group and I were major contributors to the very recent measurement of Higgs bosons interacting with top quarks. That observation was extremely challenging. We examined five years of collision data, and my team worked intensively on advanced machine-learning techniques and statistics.

    In addition to studying the Higgs and searching for dark matter, my group and I also contributed to the silicon pixel detector, to the trigger system [that identifies potentially interesting collisions], and to the computing system in the ATLAS detector. We are now improving these during the shutdown and upgrade of the LHC. We are also very excited about the near future, because we plan to start using quantum computing to do our data analysis.

    6
    Wu at CERN. Thi My Lien Nguyen/Quanta Magazine

    Do you have any advice for young physicists just starting their careers?

    Some of the young experimentalists today are a bit too conservative. In other words, they are afraid to do something that is not in the mainstream. They fear doing something risky and not getting a result. I don’t blame them. It’s the way the culture is. My advice to them is to figure out what the most important experiments are and then be persistent. Good experiments always take time.

    But not everyone gets to take that time.

    Right. Young students don’t always have the freedom to be very innovative, unless they can do it in a very short amount of time and be successful. They don’t always get to be patient and just explore. They need to be recognized by their collaborators. They need people to write them letters of recommendation.

    The only thing that you can do is work hard. But I also tell my students, “Communicate. Don’t close yourselves off. Try to come up with good ideas on your own but also in groups. Try to innovate. Nothing will be easy. But it is all worth it to discover something new.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    In achievement and prestige, the University of Wisconsin–Madison has long been recognized as one of America’s great universities. A public, land-grant institution, UW–Madison offers a complete spectrum of liberal arts studies, professional programs and student activities. Spanning 936 acres along the southern shore of Lake Mendota, the campus is located in the city of Madison.

     
  • richardmitnick 4:19 pm on June 19, 2018 Permalink | Reply
    Tags: , Sunway TaihuLight China, , Why the US and China's brutal supercomputer war matters, WIRED   

    From Wired: “Why the US and China’s brutal supercomputer war matters” 

    Wired logo

    Wired

    19 June 2018
    Chris Stokel-Walker

    ORNL IBM AC922 SUMMIT supercomputer. Credit: Carlos Jones, Oak Ridge National Laboratory/U.S. Dept. of Energy

    Thought global arms races are all about ballistic missiles, space or nuclear development? Think again: the new diplomatic frontline is over processing power and computer chips.
    Multi-million dollar projects to eke out an advantage in processing power aren’t really about science, they’re an exercise in soft power.

    A major shift has taken place, with a new claimant to the crown of world’s fastest supercomputer. IBM’s Summit at Oak Ridge National Laboratory in Tennessee uses Power9 CPUs and NVIDIA Tesla V100 GPUs and has 4,068 servers powered by ten petabytes of memory working concurrently to process 200,000 trillion calculations per second – 200 petaflops. That’s a lot of numbers – and here’s one more. Summit’s processing power is 117 petaflops more than the previous record-holder, China’s TaihuLight.

    Sunway TaihuLight, China, US News

    While it may seem significant, it’s actually largely symbolic, says Andrew Jones of the Numerical Algorithms Group, a high-performance computing consultancy. “I put no value on being twice as fast or 20 per cent faster other than bragging rights.”

    That’s not to say that supercomputers don’t matter. They are “being driven by science”, says Jack Dongarra, a computer science professor at the University of Tennessee and the compiler of the world’s top 500 supercomputer list. And science is driven today by computer simulation, he adds – with high-powered computers crucial to carry out those tests.

    Supercomputers can crunch data far faster and more easily than regular computers, making them ideal for handling big data – from cybersecurity to medical informatics to astronomy. “We could quite easily go another four or five orders of magnitude and still find scientific and business reasons to benefit from it,” says Jones.

    Oak Ridge, where Summit is housed, is already soliciting bids for a project called Coral II, the successor to the Coral project which resulted in the Summit supercomputer. The Coral II will involve three separate hardware systems, each of which has a price tag of $600 million, says Dongarra. The goal? To build a supercomputer capable of calculating at a rate of exaflops – five times faster than Summit.

    While they are faster and more powerful, supercomputers are actually not much different from the hardware we interact with on a daily basis, says Jones. “The basic components are the same as a standard server,” he says. But because of their scale, and the complexity involved in programming them to process information as a single, co-ordinated unit, supercomputer projects require significant financial outlay to build, and political support to attract that funding.

    That political involvement transforms them from a simple computational tool into a way of exercising soft power and stoking intercontinental rivalries.

    With Summit, the US has wrested back the title of the world’s most powerful supercomputer for the first time since 2012 – though it still languishes behind China in terms of overall processing power. China is the home of 202 of the 500 most powerful supercomputers, having overtaken the US in November 2017.

    “What’s quite striking is that in 2001 there were no Chinese machines that’d be considered a supercomputer, and today they dominate,” explains Dongarra. The sudden surge of supercomputers in China over the last two decades is an indication of significant investment, says Jones. “It’s more a reflection of who’s got their lobbying sorted than anything else,” he adds.

    Recently, the Chinese leadership has been drifting away “from an aspirational ‘catch-up with the west’ mentality to aspiring to be world class and to lead,” says Jonathan Sullivan, director of the China Policy Institute at the University of Nottingham. “These achievements like the longest bridge, biggest dam and most powerful supercomputer aren’t just practical solutions, they also have symbolic meaning,” he adds.

    Or putting it differently: bragging rights matter enormously to whoever’s on top.

    [TaihuLight is about 2 years old. The Chinese supercomputer people have not been sitting on their hands. They knew this was coming. We will see how long Summit is at the top.]

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 3:27 pm on April 6, 2018 Permalink | Reply
    Tags: , , , , , , Virginia Trimble, WIRED,   

    From UCSC and UC Irvine via WIRED: Women in STEM – “The Woman Who Knows Everything About the Universe” Virginia Trimble 

    UC Santa Cruz

    UC Santa Cruz

    UC Irvine bloc

    UC Irvine

    WIRED

    1
    For 16 years, Virginia Trimble read every astronomy paper in 23 journals. Now, her review papers are part of the canon. Universitat de València.

    In 1965, physicist Richard Feynman was busy.

    Richard Feynman © Open University

    He was busy winning the Nobel Prize, and he was busy learning to draw. One day during that productive time in his life, he saw astrophysics student Virginia Trimble striding across Caltech’s campus and thought, There’s a good model.

    Soon, she was posing for him a couple Tuesdays a month, in exchange for $5.50 each session and a lot of physics talk. She was studying a nebula, and he was, sometimes, sharing anecdotes that would later appear in one of his books, which featured everything from his bongo playing to his work on the Manhattan Project. Treatment of women in professional and academic situations has changed—and significantly so—since those sixties-California-campus days. Trimble was a student at a university that enrolled few women, in a field that enlisted few women. But her experience at Caltech wasn’t limited to sidelining model gigs. Those early days of learning and research were the beginning of a five-decade career that has turned Trimble into a powerhouse of astronomy.

    I first encountered Trimble’s work when I was an undergraduate astrophysics major. On the first day of seminar, my professor handed out a 101-page stack of paper. Flipping through its 13 sections, he explained that Trimble trawled the scientific journals and collated the year’s cosmic progress into a tome like this one. It wasn’t just a review paper laying out the state of atmospheric studies of Jupiter, or asteroid hunting, or massive star formation. It was all of everything important that had happened the previous year in astronomy—broad, comprehensive, and utterly unusual. Most unusual of all was that it contained jokes.

    Today, new technologies promise to synthesize masses of publication data for scientists. But before artificial intelligence even tried, astronomers had Trimble, who wrote these comprehensive articles every year. For 16 years, she devoted her mind to this task of curation, contextualization, and commentary. And throughout her career, she has largely eschewed long-term research with fancy telescopes, competitive funding, and approving nods from university administrators. Refusing narrow focus, she has gone solo on most of her 850 publications, focusing as much on the nature of doing astronomy as studying the universe itself.

    “I just asked questions,” she says, “and sometimes found a way to answer them.” That’s business as usual for Trimble, who has spent much of her career branching off from the already thin bough of bushwhacking female astronomers.

    When Trimble enrolled at UCLA in the 1960s, she wanted to major in archaeology. But the school only offered that field of study to graduate students. Right there in the A section of the catalog, though, was “astronomy,” a topic that her father informed her she’d always been interested in.

    So she enrolled as an astronomy student, living at home while attending the university’s gifted program. Which she was—gifted. In a 1962 LIFE package about California’s educational system, a journalist profiled Trimble for a piece called Behind a Lovely Face, a 180 I.Q. The title acted surprised that a pretty lady might also have a productive brain—but Trimble quickly made it clear that people should cease to be surprised at her smarts.

    Trimble’s father was right, and she felt drawn to the mysteries of the universe. After she finished her undergraduate degree, Trimble was accepted to a PhD program at Caltech. “It was only later that I looked in their catalog and saw that women were only admitted under exceptional circumstances,” she says, “exceptional” usually meaning “married to a male Caltech admittee.” There, Trimble studied the Crab Nebula, the dust, gas, and plasma sent speeding into space during a supernova explosion whose light reached Earth in 1054.

    Supernova remnant Crab nebula. NASA/ESA Hubble

    To work on this project, she applied for time at Palomar Observatory, an iconic be-domed telescope east of San Diego.


    Caltech Palomar Observatory, located in San Diego County, California, US, at 1,712 m (5,617 ft)

    She was only the third woman to use the telescope, and only the second to actually be granted her own time on it (Vera Rubin, a dark-matter pioneer, was the first).

    Vera Rubin measuring spectra (Emilio Segre Visual Archives AIP SPL)

    Astronomer Vera Rubin at the Lowell Observatory in 1965. (The Carnegie Institution for Science)

    The nebula’s contents are still, these centuries later, lit. They beam out bright radiation across a spectrum of wavelengths. Today, scientists know that a pulsar—the corpse of a massive star, as dense as an atomic nucleus and the size of a city, spinning 30 times a second—lurks at the center and energizes it. But back when Trimble was doing her dissertation, pulsars were just being discovered, and no one knew the Crab hosted one. “It was quite a mystery what kept the thing as bright as it is now,” she says.

    For her doctoral work, she measured the motions of the nebula’s filaments, and found, among other things, that the gas had sped up its flight from the center of the explosion since that explosion had happened (weird!) and that it was around 6,500 light-years away. Discovery was all right, but its details—so many photographic plates, so many similar, tedious observations—wasn’t the most fun. She sang, danced, on the side, to liven life up. But did she enjoy the telescope part? I ask. Going to a mountaintop, commanding a large instrument, gathering her own data about the universe with her own hands?

    “Noooooo,” she says. “It was cold, and I hate being cold.”

    Trimble soon realized she didn’t want to look at the Crab Nebula—or at supernova remnants more generally, or at anything, really—for the rest of her life. She preferred independence to teams. She didn’t want to hand a bunch of her grant money over to UC Irvine, where she became a tenured astronomer. So, instead of all that, she started publishing papers that took an aerial view of the field of astronomy.

    Like any scientist, she liked to wonder. And, when people began asking her to give big talks at conferences, she started wondering more about how science gets made, and why, and by whom. “I always figured this was my opportunity to say something that might not otherwise not get said,” she says. So instead of, say, summarizing the conference’s topic, she analyzed big-picture questions: How did this sub-field become interesting? Why are we worrying about this particular research subject now? Whose work did we leave out at this meeting?

    She wondered whether it paid to go to a good graduate school, in terms of career advancement (it did). She wondered which telescopes birthed the most papers, and found that a huge number of papers came from non-celebrity instruments. She wondered about the narrative arc that led to scientific consensus, and wrote a paper that tracked the progress of different scientific debates—over things like the nature of Jupiter’s Great Red Spot and the existence of dark matter.

    And then there was that time she trolled her colleagues, publishing this paper suggesting that the blue star next to a suspected black hole—the first real black hole candidate—was smaller than people thought. If that was true, it would also mean the black hole was smaller. Too small, in fact, to be a black hole at all. Two different groups instantly set out to prove her incorrect.

    “I knew it was wrong when I suggested doing it,” she says. “It was a way to get people to go out and do observations.”

    Much of her work seems to demand that astronomers think differently, perhaps situate themselves a little more, rather than imagining that their research is standalone, decoupled from larger culture. She’s recently been working, for instance, on a series about how World War I influenced the development of general relativity, and on a chapter for a book about people who maybe should have won the Nobel Prize and didn’t.

    “Is it fun?” I ask.

    “It’s certainly fun,” she says, “or I wouldn’t do it.”

    If Trimble was asking questions other astronomers didn’t think of, or at least didn’t investigate, it may have been because she knew so much more than them. Each year starting in 1991, she read every article—every one—in 23 journals. “I quickly decided whether this was anything I would ever want to know about again,” she says. If it was, it got a line in her notebook (two lines if it was super interesting). When it came time to write, she’d go back to her notebook, cull a bit, organize the entries into topics, and then write what was essentially a historical record of that annum, with the year’s accumulated cosmic knowledge.

    Here’s what she liked best about it: “I got to tell these nasty jokes,” she says. Like this one, from the 2005 paper that I read in college: “If every galaxy has [a black hole], why do people talk about them so much? Well, the same could probably be said about human private parts, which also have in common with black holes a central location and, as a rule, concealing material around.”

    But around 2007, editorial interest in the review declined, around the same time that printing and reading journal articles on paper went out of fashion. “I can’t read 6,000 papers online,” she says. Staring at a screen that long is intense. “I start seeing jagged lightning patterns,” she says.

    Now, no single person knows what all the world’s astronomers do all day. And it would be hard for a younger scientist to take Trimble’s task on again: Academic science doesn’t value broad-mindedness, in practice. It’s a publish or perish world full of big collaborations, in which most people nest in their niche of the knowledge-creation establishment.

    But despite that, the larger astronomical community seems to agree that Trimble’s contributions were valuable. Trimble has been a vice president within the International Astronomical Union and the vice president of the American Astronomical Society, which also gave her the George Van Biesbroeck prize, “for long-term extraordinary or unselfish service to astronomy.” The American Association of Physics Teachers gave her its Klopsteg Memorial Lecture Award, which “recognizes outstanding communication of the excitement of contemporary physics to the general public.”

    But, perhaps most fittingly, the International Astronomical Union recently named an asteroid after her. Now called 9271Trimble, the space rock travels solo, within a belt of others like itself.

    When I called to interview Trimble for this article, she asked if I received the 40 or so scanned pages she sent—the beginning of her memoir. In it, she recounts those posing sessions at Caltech. Feynman “didn’t like silence,” Trimble wrote, so he talked, and sometimes listened. “Heard many of the anecdotes that appear in Surely You’re Joking,” she continued, referring to Feynman’s most-famous book, “and some that don’t.”

    The memoir is obviously unfinished, she says—dozens of pages and not even past her early years. “I got bored,” she explains. “I just got bored.” It was never, after all, Trimble’s style to stick to one topic.

    See the full article here .

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    UC Irvine Campus

    Since 1965, the University of California, Irvine has combined the strengths of a major research university with the bounty of an incomparable Southern California location. UCI’s unyielding commitment to rigorous academics, cutting-edge research, and leadership and character development makes the campus a driving force for innovation and discovery that serves our local, national and global communities in many ways.

    With more than 29,000 undergraduate and graduate students, 1,100 faculty and 9,400 staff, UCI is among the most dynamic campuses in the University of California system. Increasingly a first-choice campus for students, UCI ranks among the top 10 U.S. universities in the number of undergraduate applications and continues to admit freshmen with highly competitive academic profiles.

    UCI fosters the rigorous expansion and creation of knowledge through quality education. Graduates are equipped with the tools of analysis, expression and cultural understanding necessary for leadership in today’s world.

    Consistently ranked among the nation’s best universities – public and private – UCI excels in a broad range of fields, garnering national recognition for many schools, departments and programs. Times Higher Education ranked UCI No. 1 among universities in the U.S. under 50 years old. Three UCI researchers have won Nobel Prizes – two in chemistry and one in physics.

    The university is noted for its top-rated research and graduate programs, extensive commitment to undergraduate education, and growing number of professional schools and programs of academic and social significance. Recent additions include highly successful programs in public health, pharmaceutical sciences and nursing science; an expanding education school; and a law school already ranked among the nation’s top 10 for its scholarly impact.

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    UCO Lick Shane Telescope
    UCO Lick Shane Telescope interior
    Shane Telescope at UCO Lick Observatory, UCSC

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    UC Santa Cruz campus
    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory's Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
    Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

    Search for extraterrestrial intelligence expands at Lick Observatory
    New instrument scans the sky for pulses of infrared light
    March 23, 2015
    By Hilary Lebow
    1
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    5
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

     
  • richardmitnick 3:26 pm on March 19, 2018 Permalink | Reply
    Tags: , , , , , , To Understand the Universe Physicists Are Building Their Own, , WIRED   

    FromUBC via Wired: “To Understand the Universe, Physicists Are Building Their Own” 

    U British Columbia bloc

    University of British Columbia

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    Wired

    03.16.18
    Katia Moskvitch

    1
    Inflation is impossible to prove directly. Which is why some physicists want to mimic it in a lab. PASIEKA/GETTY IMAGES.

    Silke Weinfurtner is trying to build the universe from scratch. In a physics lab at the University of Nottingham—close to the Sherwood forest of legendary English outlaw Robin Hood—she and her colleagues will work with a huge superconducting coil magnet, 1 meter across. Inside, there’s a small pool of liquid, whose gentle ripples stand to mimic the matter fluctuations that gave rise to the structures we observe in the cosmos.

    Weinfurtner isn’t an evil genius hell-bent on creating a world of her own to rule. She just wants to understand the origins of the one we already have.

    The Big Bang is by far the most popular model of our universe’s beginnings, but even its fans disagree about how it happened. The theory depends on the existence of a hypothetical quantum field that stretched the universe ultra-rapidly and uniformly in all directions, expanding it by a huge factor in a fraction of a second: a process dubbed inflation. But that inflation or the field responsible for it—the inflaton—is impossible to prove directly. Which is why Weinfurtner wants to mimic it in a lab.

    If the Big Bang theory is right, the baby universe would have been created with tiny ripples—so-called ‘quantum fluctuations’—which got stretched during inflation and turned into matter and radiation, or light. These fluctuations are thought to have eventually magnified to cosmic size, seeding galaxies, stars, and planets. And it’s these tiny ripples that Weinfurtner wants to model with that massive superconducting magnet. Inside, she’ll put a circular tank, some 6 centimeters in diameter, filled with layered water and butanol (the liquids have different densities, so they don’t mix).

    Then, her group of researchers will kick in the artificial gravity distortions. “The strength of the magnetic field varies with its position,” says Richard Hill, one of the paper’s co-authors. “By moving the pool to different regions of the field, the effective gravitational force can be increased or decreased,” he says, “and can even be turned upside-down.”

    By varying gravity, the team hopes to create ripples—but unlike those on a pond, the distortions will appear between the two liquids. “By carefully adjusting the speed of the ripples we can model an inflating universe,” says another team member, Anastasios Avgoustidis. In cosmic inflation, space rapidly expands while the ripples of matter propagate at a constant speed—and in the experiment, the speed of the ripples rapidly decreases as the liquid’s volume remains constant. “The equations describing the propagation of ripples in these two scenarios are identical,” Avgoustidis says.

    That’s important: If the resulting fluctuations look as if they might trigger structures like those found in today’s universe, then we may have had a glimpse of how inflation worked.

    This isn’t the first time Weinfurtner—or anyone else—has tried to mimic cosmic phenomena on a tiny scale. Around the world, astrophysicists can be found in labs, developing ever more sophisticated set-ups using sound waves that travel just like light waves in strong gravitational fields, or magnets to trigger perturbations in fluids and gases.

    Last June, Weinfurtner used a large water tank with a sink in the middle to mimic another difficult-to-observe phenomenon: the superradiance of a black hole. And it was William Unruh, a physicist at the University of British Columbia in Vancouver (and Weinfurtner’s advisor a decade ago), who pioneered the idea of simulating gravity in a lab in 1981. After all, “we cannot rerun the universe—and cannot live long enough to see the results of the experiment if we could,” says Unruh.

    Analog gravity experiments have gotten more sophisticated since Unruh’s first experiment, which used a fluid simulation of gravity to show that the event horizon of a real black hole does to light what a sonic black hole does to sound. In other words: What we can measure and express in the lab can be used to explore properties of astrophysical black holes. It even works for the famous Hawking radiation, the prediction that black holes radiate heat and at some point will totally evaporate. A few years ago, Jeff Steinhauer of the Technion in Haifa, Israel, discovered the radiation’s sonic analog [Nature Physics].

    Simulations are being used to study other aspects of inflation, too. A few years ago, a team led by Christoph Westbrook of CNRS (The French National Center for Scientific Research) in Paris studied the production of quantum particles by ‘wiggling’ a ring Bose Einstein condensate—a state of matter in which the atoms have been cooled to near absolute zero, making them behave as a single quantum object [PACS]. During inflation, the temperature of the universe dropped drastically, before starting to rise again when the inflation ceased with the process called ‘reheating’—leading to the ordinary Big Bang expansion.

    Another experiment last October, led by physicist Stephen Eckel at the Joint Quantum Institute at the National Institute of Standards and Technology and University of Maryland, also used a Bose Einstein condensate to observe the stretching of sound waves—analogous to the stretching, or redshifting, of light that happens as the universe expands. The team also observed an effect similar to the reheating process.

    Weinfurtner says that her ‘novel’ setup can work without a Bose Einstein condensate. That means that the system will be too hot to observe quantum fluctuations directly, says Unruh. But the authors argue that it will be possible to observe the fluctuations via the thermal noise in their system—an analog of quantum noise.

    Their approach, say the authors, will allow them to mimic a long expansion phase, achieving—using the technical language—‘many e-folds,’ a parameter that measures the duration of inflation. Researchers believe that inflation increased the size of the universe by more than a factor of 10^26—or more than 60 e-folds—in just a fraction of a second. The new experiment, if successful, would simulate inflation for much longer period than previous lab set-ups, or have “many more e-folds than any other, enough to put the results beyond doubt,” says Ian Moss of the University of Newcastle. “You need some time to elapse for the system to forget its initial conditions and settle down to the state governed by inflationary fluctuations,” he says.

    “It is possible that they will uncover new physics that help to inform future cosmological models,” says Eckel. “Or, on the reverse, help to test some aspect of future cosmological models.”

    Not everyone is convinced that simulating our universe’s first moments in the lab will help cosmology, though. Ted Jacobson of the University of Maryland thinks that such experiments are “not so much verifying something we are uncertain about, but rather implementing and observing it in a lab.” Why mimic the universe in the lab? “It’s fun. And it may suggest new phenomena we didn’t think of in cosmology,” he says.

    Avi Loeb, an astrophysicist at Harvard University, is not as optimistic. He says that Weinfurtner’s proposed analogy of creating ripples between two fluids in a tank will not extend to the “fundamental physical nature” of quantum fluctuations—because the experiment simply reproduces the equations physicists already use to describe inflation. If these equations are missing a fundamental ingredient, the experiment will not reveal it. “While analog laboratory experiments could incorporate quantum mechanical effects, they do not involve the interplay of quantum mechanics with gravity in the way that black holes and inflation do,” he says.

    Weinfurtner’s experiment is tailored to reproduce our existing notion of inflation, Loeb adds – but it’s not meant to test it at a fundamental level. “The only way to get a discrepancy between the experiment and our notion of inflation is if we did the math wrong for one of these systems. Otherwise, we will learn nothing new,” he says.

    The real test of inflation would be, Loeb says, the production of the substance that propelled it—the inflaton—in the lab. But this would require reaching energies up to a trillion times larger than those achieved in our most powerful particle accelerator, the Large Hadron Collider—and such a test seems unlikely in the near future.

    “Just mimicking the equations of an analogous system is a metaphor to the real system, not an actual test of its fundamental properties,” says Loeb. It’s like “smelling food instead of eating the actual food,” he adds, only “the latter has the real value.”

    That’s true, but sometimes the smells from a kitchen can tell you a lot about what was served for dinner.

    See the full article here .

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    The University of British Columbia is a global centre for research and teaching, consistently ranked among the 40 best universities in the world. Since 1915, UBC’s West Coast spirit has embraced innovation and challenged the status quo. Its entrepreneurial perspective encourages students, staff and faculty to challenge convention, lead discovery and explore new ways of learning. At UBC, bold thinking is given a place to develop into ideas that can change the world.

     
  • richardmitnick 1:26 pm on January 1, 2018 Permalink | Reply
    Tags: , , WIRED   

    From WIRED: “The Sunny Optimism of Clean Energy Shines Through Tech’s Gloom” 

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    WIRED

    01.01.18
    Clive Thompson

    1
    ZOHAR LAZAR

    The mood around tech is dark these days. Social networks are a cesspool of harassment and lies. On-demand firms are producing a bleak economy of gig labor. AI learns to be racist. Is there anyplace where the tech news is radiant with old-fashioned optimism? Where good cheer abounds?

    Why, yes, there is: clean energy. It is, in effect, the new Silicon Valley—filled with giddy, breathtaking ingenuity and flat-out good news.

    This might seem surprising given the climate-change denialism in Washington. But consider, first, residential solar energy. The price of panels has plummeted in the past decade and is projected to drop another 30 percent by 2022. Why? Clever engineering breakthroughs, like the use of diamond wire to slice silicon wafers into ever-skinnier slabs, producing higher yields with less raw material.

    Manufacturing costs are down. According to US government projections, the fastest-growing occupation of the next 10 years will be solar voltaic installer. And you know who switched to solar power last year, because it was so cheap? The Kentucky Coal Museum.

    Tech may have served up Nazis in social media streams, but, hey, it’s also creating microgrids—a locavore equivalent for the solar set. One of these efforts is Brooklyn-based LO3 Energy, a company that makes a paperback-sized device and software that lets owners of solar-equipped homes sell energy to their neighbors—verifying the transactions using the blockchain, to boot. LO3 is testing its system in 60 homes on its Brooklyn grid and hundreds more in other areas.

    “Buy energy and you’re buying from your community,” LO3 founder Lawrence Or­sini tells me. His chipsets can also connect to smart appliances, so you could save money by letting his system cycle down your devices when the network is low on power. The company uses internet logic—smart devices that talk to each other over a dumb network—to optimize power consumption on the fly, making local clean energy ever more viable.

    But wait, doesn’t blockchain number-crunching use so much electricity it generates wasteful heat? It does. So Orsini invented DareHenry, a rack crammed with six GPUs; while it processes math, phase-­changing goo absorbs the outbound heat and uses it to warm a house. Blockchain cogeneration, people! DareHenry is 4 feet of gorgeous, Victorian­esque steampunk aluminum—so lovely you’d want one to show off to guests.

    Solar and blockchain are only the tip of clean tech. Within a few years, we’ll likely see the first home fuel-cell systems, which convert natural gas to electricity. Such systems are “about 80 percent efficient,” marvels Garry Golden, a futurist who has studied clean energy. (He’s also on LO3’s grid, with the rest of his block.)

    The point is, clean energy has a utopian spirit that reminds me of the early days of personal computers. The pioneers of the 1970s were crazy hackers, hell-bent on making machines cheap enough for the masses. Everyone thought they were nuts, or small potatoes—yet they revolutionized communication. When I look at Orsini’s ­blockchain-based energy-trading routers, I see the Altair. And there are oodles more inventors like him.

    Mind you, early Silicon Valley had something crucial that clean energy now does not: massive federal government support. The military bought tons of microchips, helping to scale up computing. Trump’s band of climate deniers aren’t likely to be buyers of first resort for clean energy, but states can do a lot. California already has, for instance, by creating quotas for renewables. So even if you can’t afford this stuff yourself, you should pressure state and local officials to ramp up their solar energy use. It’ll give us all a boost of much-needed cheer.

    See the full article here .

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  • richardmitnick 1:19 pm on December 2, 2017 Permalink | Reply
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    From WIRED: “A Hidden Supercluster Could Solve the Mystery of the Milky Way” 

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    WIRED

    12.02.17
    Liz Kruesi

    1
    The Vela supercluster in its wider surroundings: The image displays the smoothed redshift distribution of galaxies in and around the Vela supercluster (larger ellipse; VSC). The centre of the image, so-called the Zone of Avoidance, is covered by the Milky Way (with its stellar fields and dust layers shown in grey scale), which obscures all structures behind it. Colour indicates the distance ranges of all galaxies within 500 – 1000 million light years (yellow is close to the peak of the Vela supercluster, green is nearer and orange further away). The ellipse marks the approximate extent of the Vela Supercluster, crossing the Galactic Plane. The VSC structure was revealed thanks to the new low latitude spectroscopic redshifts. Given its prominence on either side of the plane of the Milky Way it would be highly unlikely for these cosmic large-scale structures not to be connected across the Galactic Plane. The structure may be similar in aggregate mass to the Shapley Concentration (SC, smaller ellipse), although much more extended. The so-called “Great Attractor” (GA), located much closer to the Milky Way, is an example of a large web structure that crosses the Galactic Plane, although much smaller in extent than VSC. The central, dust-shrouded part of the VSC remains unmapped in the current Vela survey. Also visible are the Milky Way’s two satellite galaxies, LMC and SMC, located south of the Galactic plane. Image credit: Thomas Jarrett (UCT)

    2
    An illustration of the Vela Supercluster peeking out from behind the Milky Way’s Zone of Avoidance. Mike Zeng/Quanta Magazine

    Glance at the night sky from a clear vantage point, and the thick band of the Milky Way will slash across the sky. But the stars and dust that paint our galaxy’s disk are an unwelcome sight to astronomers who study all the galaxies that lie beyond our own. It’s like a thick stripe of fog across a windshield, a blur that renders our knowledge of the greater universe incomplete. Astronomers call it the Zone of Avoidance.

    3
    Zone of Avoidance. NASA/Spitzer

    Renée Kraan-Korteweg has spent her career trying to uncover what lies beyond the zone. She first caught a whiff of something spectacular in the background when, in the 1980s, she found hints of a potential cluster of objects on old photographic survey plates. Over the next few decades, the hints of a large-scale structure kept coming.

    Late last year, Kraan-Korteweg and colleagues announced that they had discovered an enormous cosmic structure: a “supercluster” of thousands upon thousands of galaxies. The collection spans 300 million light years, stretching both above and below the galactic plane like an ogre hiding behind a lamppost. The astronomers call it the Vela Supercluster, for its approximate position around the constellation Vela.

    Milky Way Movers

    The Milky Way, just like every galaxy in the cosmos, moves. While everything in the universe is constantly moving because the universe itself is expanding, since the 1970s astronomers have known of an additional motion, called peculiar velocity. This is a different sort of flow that we seem to be caught in. The Local Group of galaxies—a collection that includes the Milky Way, Andromeda and a few dozen smaller galactic companions—moves at about 600 kilometers per second with respect to the leftover radiation from the Big Bang.

    Local Group. Andrew Z. Colvin 3 March 2011

    Andromeda Galaxy Adam Evans

    Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Over the past few decades, astronomers have tallied up all the things that could be pulling and pushing on the Local Group — nearby galaxy clusters, superclusters, walls of clusters and cosmic voids that exert a non-negligible gravitational pull on our own neighborhood.

    Laniakea supercluster. From Nature The Laniakea supercluster of galaxies R. Brent Tully, Hélène Courtois, Yehuda Hoffman & Daniel Pomarède at http://www.nature.com/nature/journal/v513/n7516/full/nature13674.html. Milky Way is the red dot.

    The biggest tugboat is the Shapley Supercluster, a behemoth of 50 million billion solar masses that resides about 500 million light years away from Earth (and not too far away in the sky from the Vela Supercluster). It accounts for between a quarter and half of the Local Group’s peculiar velocity.

    3
    Shapley Supercluster. http://www.atlasoftheuniverse.com/superc/shapley.html

    The remaining motion can’t be accounted for by structures astronomers have already found. So astronomers keep looking farther out into the universe, tallying increasingly distant objects that contribute to the net gravitational pull on the Milky Way. Gravitational pull decreases with increasing distance, but the effect is partly offset by the increasing size of these structures. “As the maps have gone outward,” said Mike Hudson, a cosmologist at the University of Waterloo in Canada, “people continue to identify bigger and bigger things at the edge of the survey. We’re looking out farther, but there’s always a bigger mountain just out of sight.” So far astronomers have only been able to account for about 450 to 500 kilometers per second of the Local Group’s motion.

    Astronomers still haven’t fully scoured the Zone of Avoidance to those same depths, however. And the Vela Supercluster discovery shows that something big can be out there, just out of reach.

    In February 2014, Kraan-Korteweg and Michelle Cluver, an astronomer at the University of Western Cape in South Africa, set out to map the Vela Supercluster over a six-night observing run at the Anglo-Australian Telescope in Australia. Kraan-Korteweg, of the University of Cape Town, knew where the gas and dust in the Zone of Avoidance was thickest; she targeted individual spots where they had the best chance of seeing through the zone. The goal was to create a “skeleton,” as she calls it, of the structure. Cluver, who had prior experience with the instrument, would read off the distances to individual galaxies.

    That project allowed them to conclude that the Vela Supercluster is real, and that it extends 20 by 25 degrees across the sky. But they still don’t understand what’s going on in the core of the supercluster. “We see walls crossing the Zone of Avoidance, but where they cross, we don’t have data at the moment because of the dust,” Kraan-Korteweg said. How are those walls interacting? Have they started to merge? Is there a denser core, hidden by the Milky Way’s glow?

    And most important, what is the Vela’s Supercluster’s mass? After all, it is mass that governs the pull of gravity, the buildup of structure.

    How to See Through the Haze

    While the Zone’s dust and stars block out light in optical and infrared wavelengths, radio waves can pierce through the region. With that in mind, Kraan-Korteweg has a plan to use a type of cosmic radio beacon to map out everything behind the thickest parts of the Zone of Avoidance.

    The plan hinges on hydrogen, the simplest and most abundant gas in the universe. Atomic hydrogen is made of a single proton and an electron. Both the proton and the electron have a quantum property called spin, which can be thought of as a little arrow attached to each particle. In hydrogen, these spins can line up parallel to each other, with both pointing in the same direction, or antiparallel, pointing in opposite directions. Occasionally a spin will flip—a parallel atom will switch to antiparallel. When this happens, the atom will release a photon of light with a particular wavelength.

    The likelihood of one hydrogen atom’s emitting this radio wave is low, but gather a lot of neutral hydrogen gas together, and the chance of detecting it increases. Luckily for Kraan-Korteweg and her colleagues, many of Vela’s member galaxies have a lot of this gas.

    During that 2014 observing session, she and Cluver saw indications that many of their identified galaxies host young stars. “And if you have young stars, it means they recently formed, it means there’s gas,” Kraan-Korteweg said, because gas is the raw material that makes stars.

    The Milky Way has some of this hydrogen, too—another foreground haze to interfere with observations. But the expansion of the universe can be used to identify hydrogen coming from the Vela structure. As the universe expands, it pulls away galaxies that lie outside our Local Group and shifts the radio light toward the red end of the spectrum. “Those emission lines separate, so you can pick them out,” said Thomas Jarrett, an astronomer at the University of Cape Town and part of the Vela Supercluster discovery team.

    While Kraan-Korteweg’s work over her career has dug up some 5,000 galaxies in the Vela Supercluster, she is confident that a sensitive enough radio survey of this neutral hydrogen gas will triple that number and reveal structures that lie behind the densest part of the Milky Way’s disk.

    That’s where the MeerKAT radio telescope enters the picture. Located near the small desert town of Carnarvon, South Africa, the instrument will be more sensitive than any radio telescope on Earth. Its 64th and final antenna dish was installed in October, although some dishes still need to be linked together and tested. A half array of 32 dishes should be operating by the end of this year, with the full array following early next year.

    SKA Meerkat telescope, 90 km outside the small Northern Cape town of Carnarvon, SA

    Kraan-Korteweg has been pushing over the past year for observing time in this half-array stage, but if she isn’t awarded her requested 200 hours, she’s hoping for 50 hours on the full array. Both options provide the same sensitivity, which she and her colleagues need to detect the radio signals of neutral hydrogen in thousands of individual galaxies hundreds of light years away. Armed with that data, they’ll be able to map what the full structure actually looks like.

    Cosmic Basins

    Hélène Courtois, an astronomer at the University of Lyon, is taking a different approach to mapping Vela. She makes maps of the universe that she compares to watersheds, or basins. In certain areas of the sky, galaxies migrate toward a common point, just as all the rain in a watershed flows into a single lake or stream. She and her colleagues look for the boundaries, the tipping points of where matter flows toward one basin or another.

    A few years ago, Courtois and colleagues used this method to attempt to define our local large-scale structure, which they call Laniakea. The emphasis on defining is important, Courtois explains, because while we have definitions of galaxies and galaxy clusters, there’s no commonly agreed-upon definition for larger-scale structures in the universe such as superclusters and walls.

    Part of the problem is that there just aren’t enough superclusters to arrive at a statistically rigorous definition. We can list the ones we know about, but as aggregate structures filled with thousands of galaxies, superclusters show an unknown amount of variation.

    Now Courtois and colleagues are turning their attention farther out. “Vela is the most intriguing,” Courtois said. “I want to try to measure the basin of attraction, the boundary, the frontier of Vela.” She is using her own data to find the flows that move toward Vela, and from that she can infer how much mass is pulling on those flows. By comparing those flow lines to Kraan-Korteweg’s map showing where the galaxies physically cluster together, they can try to address how dense of a supercluster Vela is and how far it extends. “The two methods are totally complementary,” Courtois added.

    The two astronomers are now collaborating on a map of Vela. When it’s complete, the astronomers hope that they can use it to nail down Vela’s mass, and thus the puzzle of the remaining piece of the Local Group’s motion—“that discrepancy that has been haunting us for 25 years,” Kraan-Korteweg said. And even if the supercluster isn’t responsible for that remaining motion, collecting signals through the Zone of Avoidance from whatever is back there will help resolve our place in the universe.

    See the full article here .

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  • richardmitnick 12:21 pm on September 11, 2017 Permalink | Reply
    Tags: , , WIRED   

    From WIRED: “The Astonishing Engineering Behind America’s Latest, Greatest Supercomputer” 

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    WIRED

    1
    HOTLITTLEPOTATO

    If you want to do big, serious science, you’ll need a serious machine. You know, like a giant water-cooled computer that’s 200,000 times more powerful than a top-of-the-line laptop and that sucks up enough energy to power 12,000 homes.

    You’ll need Summit, a supercomputer nearing completion at the Oak Ridge National Laboratory in Tennessee.

    ORNL IBM Summit Supercomputer

    When it opens for business next year, it’ll be the United States’ most powerful supercomputer and perhaps the most powerful in the world. Because as science gets bigger, so too must its machines, requiring ever more awesome engineering, both for the computer itself and the building that has to house it without melting. Modeling the astounding number of variables that affect climate change, for instance, is no task for desktop computers in labs. Some goes for genomics work and drug discovery and materials science. If it’s wildly complex, it’ll soon course through Summit’s circuits.

    Summit will be five to 10 times more powerful than its predecessor, Oak Ridge’s Titan supercomputer, which will continue running its science for about a year after Summit comes online.

    ORNL Cray Titan XK7 Supercomputer

    (Not that there’s anything wrong with Titan. It’s just that at 5 years old, the machine is getting on in years by supercomputer standards.) But it’ll be pieced together in much the same way: cabinet after cabinet of so-called nodes. While each node for Titan, all 18,688 of them, consists of one CPU and one GPU, with Summit it’ll be two CPUs working with six GPUs.

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    Diagram showing how chilled water is delivered to the building.
    Heery International

    Think of the GPU as a turbocharger for the CPU in this relationship. While not all supercomputers use this setup, known as a heterogeneous architecture, those that do get a boost―each of the 4,600 nodes in Summit can manage 40 teraflops. So at peak performance, Summit will hit 200 petaflops, a petaflop being one million billion operations a second. “So we envision research teams using all of those GPUs on every single node when they run, that’s sort of our mission as a facility,” says Stephen McNally, operations manager.

    Performing all those operations sucks up a lot of power and generates a ton of heat. That poses a daunting challenge for Heery, the company charged with preventing Summit from overheating and powering the building that houses it. Heery’s piping in 20 megawatts of electricity (the supercomputer itself will run on 15 megawatts), enough juice to power a decent-sized city. “12,000 Southern homes with their air conditioners cranking would be roughly 20 megawatts of power,” says George Wellborn, senior associate at Heery. Luckily, Oak Ridge is hooked up to the Tennessee Valley Authority, which in Tennessee alone has a generating capacity of nearly 20,000 megawatts from 19 hydroelectric dams, two nuclear power plants, and too many other sources to get into here.

    Another engineering pickle: Each of the supercomputer’s 4,600 nodes needs to be cooled individually. Summit will use water. (Titan uses a refrigerant. You could also cool your electronics in a bath of mineral oil, if you were so inclined.) “Every one of those nodes is using a cold plate technology, where we’re putting water through a cold plate that’s directly on top,” says Jim Rogers, director for computing and facilities. “So 70 percent of the heat that’s generated by this thing can be absorbed by that cold plate.”

    3
    Overhead view of Summit. Heery International

    Curiously, this isn’t super-chilled water―it’s a comfortable 70 degrees Fahrenheit. Why? Because if you drop the temperature too much, you’ll form dew, which is a great way to ruin a supercomputer. “You have to have higher flow rates to carry the heat away,” Rogers says (we’re talking a max flow of nearly 8,000 gallons per minute), “but that tradeoff is good in terms of energy efficiency and operating cost.”

    Summit still has to … summit some final steps before it can start crunching heavy-duty science. Its cabinets should all be installed by late October, then it will undergo a year of testing and debugging. But soon enough, one of the most impressive devices humankind has ever assembled will go node to node with the best supercomputers in the world.

    See the full article here .

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  • richardmitnick 3:02 pm on June 6, 2017 Permalink | Reply
    Tags: An IBM Breakthrough Ensures Silicon Will Keep Shrinking, , , , WIRED   

    From WIRED: “An IBM Breakthrough Ensures Silicon Will Keep Shrinking” 

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    WIRED

    1
    IBM scientists at the SUNY Polytechnic Institute Colleges of Nanoscale Science and Engineering’s NanoTech Complex in Albany, NY prepare test wafers with 5nm silicon nanosheet transistors, loaded into the front opening unified pod, or FOUPs, to test an industry-first process of building 5nm transistors using silicon nanosheets.Connie Zhou

    The limits of silicon have not been reached quite yet.

    Today, an IBM-led group of researchers have detailed a breakthrough transistor design, one that will enable processors to continue their Moore’s Law march toward smaller, more affordable iterations. Better still? They achieved it not with carbon nanotubes or some other theoretical solution, but with an inventive new process that actually works, and should scale up to the demands of mass manufacturing within several years.

    That should also, conveniently enough, be just in time to power the self-driving cars, on-board artificial intelligence, and 5G sensors that comprise the ambitions of nearly every major tech player today—which was no sure thing.

    5nm Or Bust

    For decades, the semiconductor industry has obsessed over smallness, and for good reason. The more transistors you can squeeze into a chip, the more speed and power efficiency gains you reap, at lower cost. The famed Moore’s Law is simply the observation made by Intel co-founder Gordon Moore, in 1965, that the number of transistors had doubled every year. In 1975, Moore revised that estimate to every two years. While the industry has fallen off of that pace, it still regularly finds ways to shrink.

    Doing so has required no shortage of inventiveness. The last major breakthrough came in 2009, when researchers detailed a new type of transistor design called FinFET. The first manufacturing of a FinFET transistor design in 2012 gave the industry a much-needed boost, enabling processors made on a 22-nanometer process. FinFET was a revolutionary step in its own right, and the first major shift in transistor structure in decades. Its key insight was to use a 3-D structure to control electric current, rather than the 2-D “planar” system of years past.

    ”Fundamentally, FinFET structure is a single rectangle, with the three sides of the structure covered in gates,” says Mukesh Khare, vice president of semiconductor research for IBM Research. Think of the transistor as a switch; applying different voltages to the gate turns the transistor “on” or “off.” Having three sides surrounded by gates maximizes the amount of current flowing in the “on” state, for performance gains, and minimizes the amount of leakage in the “off” state, which improves efficiency.

    But just five years later, those gains already threaten to run dry. “The problem with FinFET is it’s running out of steam,” says Dan Hutcheson, CEO of VLSI Research, which focuses on semiconductor manufacturing. While FinFET underpins today’s bleeding-edge 10nm process chips, and should be sufficient for 7nm as well, the fun stops there. “Around 5nm, in order to keep the scaling and transistor working, we need to move to a different structure,” Hutcheson says.

    Enter IBM.

    Rather than FinFET’s vertical fin structure, the company—along with research partners GlobalFoundries and Samsung—has gone horizontal, layering silicon nanosheets in a way that effectively results in a fourth gate.

    3
    A scan of IBM Research Alliance’s 5nm transistor, built using an industry-first process to stack silicon nanosheets as the device structure.IBM

    “You can imagine that FinFET is now turned sideways, and stacked on top of each other,” says Khare. For a sense of scale, in this architecture electrical signals pass through a switch that’s the width of two or three strands of DNA.

    “It’s a big development,” says Hutcheson. “If I can make the transistor smaller, I get more transistors in the same area, which means I get more compute power in the same area.” In this case, that number leaps from 20 billion transistors in a 7nm process to 30 billion on a 5nm process, fingernail-sized chip. IBM pegs the gains at either 40 percent better performance at the same power, or 75 percent reduction in power at the same efficiency.

    Just in Time

    The timing couldn’t be better.

    Actual processors built off of this new structure aren’t expected to hit the market until 2019 at the earliest. But that roughly lines up with industry estimates for broader adoption of everything from self-driving cars to 5G, innovations that can’t scale without a functional 5nm process in place.

    4
    IBM Research scientist Nicolas Loubet holds a wafer of chips with 5nm silicon nanosheet transistors manufactured using an industry-first process that can deliver 40 percent performance enhancement at fixed power, or 75 percent power savings at matched performance.Connie Zhou

    “The world’s sitting on this stuff, artificial intelligence, self-driving cars. They’re all highly dependent on more efficient computing power. That only comes from this type of technology,” says Hutcheson. “Without this, we stop.”

    Take self-driving cars as a specific example. They may work well enough today, but they also require tens of thousands of dollars worth of chips to function, an impractical added cost for a mainstream product. A 5nm process drives those expenses way down. Think, too, of always-on IoT sensors that will collect constant streams of data in a 5G world. Or more practically, think of smartphones that can last two or three days on a charge rather than one, with roughly the same-sized battery. And that’s before you hit the categories that no one’s even thought of yet.

    “The economic value that Moore’s Law generates is unquestionable. That’s where innovations such as this one come into play, to extend scaling not by traditional ways but coming up with innovative structures,” says Khare.

    Widespread adoption of many of those technologies is still years away. And success in all of them will require a confluence of both technological and regulatory progress. At least when they get there, though, the tiny chips that make it all work will be right there waiting for them.

    See the full article here .

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  • richardmitnick 5:22 pm on June 4, 2017 Permalink | Reply
    Tags: , , , , , , , WIRED   

    From WIRED: “Cosmic Discoveries Fuel a Fight Over the Universe’s Beginnings” 

    Wired logo

    06.04.17
    Ashley Yeager

    1
    Light from the first galaxies clears the universe. ESO/L. Calçada

    Not long after the Big Bang, all went dark. The hydrogen gas that pervaded the early universe would have snuffed out the light of the universe’s first stars and galaxies. For hundreds of millions of years, even a galaxy’s worth of stars—or unthinkably bright beacons such as those created by supermassive black holes—would have been rendered all but invisible.

    Eventually this fog burned off as high-energy ultraviolet light broke the atoms apart in a process called reionization.

    Reionization era and first stars, Caltech

    But the questions of exactly how this happened—which celestial objects powered the process and how many of them were needed—have consumed astronomers for decades.

    Now, in a series of studies, researchers have looked further into the early universe than ever before. They’ve used galaxies and dark matter as a giant cosmic lens to see some of the earliest galaxies known, illuminating how these galaxies could have dissipated the cosmic fog. In addition, an international team of astronomers has found dozens of supermassive black holes—each with the mass of millions of suns—lighting up the early universe. Another team has found evidence that supermassive black holes existed hundreds of millions of years before anyone thought possible. The new discoveries should make clear just how much black holes contributed to the reionization of the universe, even as they’ve opened up questions as to how such supermassive black holes were able to form so early in the universe’s history.

    First Light

    In the first years after the Big Bang, the universe was too hot to allow atoms to form. Protons and electrons flew about, scattering any light. Then after about 380,000 years, these protons and electrons cooled enough to form hydrogen atoms, which coalesced into stars and galaxies over the next few hundreds of millions of years.

    Starlight from these galaxies would have been bright and energetic, with lots of it falling in the ultraviolet part of the spectrum. As this light flew out into the universe, it ran into more hydrogen gas. These photons of light would break apart the hydrogen gas, contributing to reionization, but as they did so, the gas snuffed out the light.

    2
    Lucy Reading-Ikkanda/Quanta Magazine

    To find these stars, astronomers have to look for the non-ultraviolet part of their light and extrapolate from there. But this non-ultraviolet light is relatively dim and hard to see without help.

    A team led by Rachael Livermore, an astrophysicist at the University of Texas at Austin, found just the help needed in the form of a giant cosmic lens.

    Gravitational Lensing NASA/ESA

    These so-called gravitational lenses form when a galaxy cluster, filled with massive dark matter, bends space-time to focus and magnify any object on the other side of it. Livermore used this technique with images from the Hubble Space Telescope to spot extremely faint galaxies from as far back as 600 million years after the Big Bang—right in the thick of reionization.

    NASA/ESA Hubble Telescope

    In a recent paper that appeared in The Astrophysical Journal, Livermore and colleagues also calculated that if you add galaxies like these to the previously known galaxies, then stars should be able to generate enough intense ultraviolet light to reionize the universe.

    Yet there’s a catch. Astronomers doing this work have to estimate how much of a star’s ultraviolet light escaped its home galaxy (which is full of light-blocking hydrogen gas) to go out into the wider universe and contribute to reionization writ large. That estimate—called the escape fraction—creates a huge uncertainty that Livermore is quick to acknowledge.

    In addition, not everyone believes Livermore’s results. Rychard Bouwens, an astrophysicist at Leiden University in the Netherlands, argues in a paper submitted to The Astrophysical Journal that Livermore didn’t properly subtract the light from the galaxy clusters that make up the gravitational lens.

    6

    As a result, he said, the distant galaxies aren’t as faint as Livermore and colleagues claim, and astronomers have not found enough galaxies to conclude that stars ionized the universe.

    If stars couldn’t get the job done, perhaps supermassive black holes could. Beastly in size, up to a billion times the mass of the sun, supermassive black holes devour matter. They tug it toward them and heat it up, a process that emits lots of light and creates luminous objects that we call quasars. Because quasars emit way more ionizing radiation than stars do, they could in theory reionize the universe.

    The trick is finding enough quasars to do it. In a paper posted to the scientific preprint site arxiv.org last month, astronomers working with the Subaru Telescope announced the discovery of 33 quasars that are about a 10th as bright as ones identified before.


    NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

    With such faint quasars, the astronomers should be able to calculate just how much ultraviolet light these supermassive black holes emit, said Michael Strauss, an astrophysicist at Princeton University and a member of the team.

    The researchers haven’t done the analysis yet, but they expect to publish the results in the coming months.

    The oldest of these quasars dates back to around a billion years after the Big Bang, which seems about how long it would take ordinary black holes to devour enough matter to bulk up to supermassive status.

    This is why another recent discovery [ApJ] is so puzzling. A team of researchers led by Richard Ellis, an astronomer at the European Southern Observatory, was observing a bright, star-forming galaxy seen as it was just 600 million years after the Big Bang.

    The galaxy’s spectrum—a catalog of light by wavelength—appeared to contain a signature of ionized nitrogen. It’s hard to ionize ordinary hydrogen, and even harder to ionize nitrogen. It requires more higher-energy ultraviolet light than stars emit. So another strong source of ionizing radiation, possibly a supermassive black hole, had to exist at this time, Ellis said.

    One supermassive black hole at the center of an early star-forming galaxy might be an outlier. It doesn’t mean there were enough of them around to reionize the universe. So Ellis has started to look at other early galaxies. His team now has tentative evidence that supermassive black holes sat at the centers of other massive, star-forming galaxies in the early universe. Studying these objects could help clarify what reionized the universe and illuminate how supermassive black holes formed at all. “That is a very exciting possibility,” Ellis said.

    All this work is beginning to converge on a relatively straightforward explanation for what reionized the universe. The first population of young, hot stars probably started the process, then drove it forward for hundreds of millions of years. Over time, these stars died; the stars that replaced them weren’t quite so bright and hot. But by this point in cosmic history, supermassive black holes had enough time to grow and could start to take over. Researchers such as Steve Finkelstein, an astrophysicist at the University of Texas at Austin, are using the latest observational data and simulations of early galactic activity to test out the details of this scenario, such as how much stars and black holes contribute to the process at different times.

    His work—and all work involving the universe’s first billion years—will get a boost in the coming years after the 2018 launch of the James Webb Space Telescope, Hubble’s successor, which has been explicitly designed to find the first objects in the universe.

    NASA/ESA/CSA Webb Telescope annotated

    Its findings will probably provoke many more questions, too.

    See the full article here .

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