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  • richardmitnick 2:56 pm on June 22, 2018 Permalink | Reply
    Tags: , , , , , SA   

    From Scientific American: “Evidence Builds for a New Kind of Neutrino” 

    Scientific American

    From Scientific American

    June 7, 2018
    Clara Moskowitz


    Physicists have caught ghostly particles called neutrinos misbehaving at an Illinois experiment, suggesting an extra species of neutrino exists. If borne out, the findings would be nothing short of revolutionary, introducing a new fundamental particle to the lexicon of physics that might even help explain the mystery of dark matter.

    Undeterred by the fact that no one agrees on what the observations actually mean, experts gathered at a neutrino conference this week in Germany are already excitedly discussing these and other far-reaching implications.

    Neutrinos are confusing to begin with. Formed long ago in the universe’s first moments and today in the hearts of stars and the cores of nuclear reactors, the miniscule particles travel at nearly the speed of light, and scarcely interact with anything else; billions pass harmlessly through your body each day, and a typical neutrino could traverse a layer of lead a light-year thick unscathed. Ever since their discovery in the mid–20th century, neutrinos were predicted to weigh nothing at all, but experiments in the 1990s showed they do have some mass—although physicists still do not know exactly how much. Stranger still, they come in three known varieties, or flavors—electron neutrinos, muon neutrinos and tau neutrinos—and, most bizarrely, can transform from one flavor to another. Because of these oddities and others, many physicists have been betting on neutrinos to open the door to the next frontier in physics.

    Now some think the door has cracked ajar. The discovery comes from 15 years’ worth of data gathered by the Mini Booster Neutrino Experiment (MiniBooNE) at Fermi National Accelerator Laboratory in Batavia, Ill. MiniBooNE detects and characterizes neutrinos by the flashes of light they occasionally create when they strike atomic nuclei in a giant vat filled with 800 tons of pure mineral oil. Its design is similar to that of an earlier project, the Liquid Scintillator Neutrino Detector (LSND) at Los Alamos National Laboratory in New Mexico. In the 1990s LSND observed a curious anomaly, a greater-than-expected number of electron neutrinos in a beam of particles that started out as muon neutrinos; MiniBooNE has now seen the same thing, in a neutrino beam generated by one of Fermilab’s particle accelerators.

    Because muon neutrinos could not have transformed directly into electron flavor over the short distance of the LSND experiment, theorists at the time proposed that some of the particles were oscillating into a fourth flavor—a “sterile neutrino”—and then turning into electron neutrinos, producing the mysterious excess. Although the possibility was tantalizing, many physicists assumed the findings were a fluke, caused by some mundane error particular to LSND. But now that MiniBooNE has observed the very same pattern, scientists are being forced to reckon with potentially more profound causes for the phenomenon. “Now you have to really say you have two experiments seeing the same physics effect, so there must be something fundamental going on,” says MiniBooNE co-spokesperson Richard Van de Water of Los Alamos. “People can’t ignore this anymore.”

    The MiniBooNE team submitted its findings on May 30 to the preprint server arXiv, and is presenting them this week at the XXVIII International Conference on Neutrino Physics and Astrophysics in Heidelberg, Germany.

    A Fourth Flavor

    Sterile neutrinos are an exciting prospect, but outside experts say it is too early to conclude such particles are behind the observations. “If it is sterile neutrinos, it’d be revolutionary,” says Mark Thomson, a neutrino physicist and chief executive of the U.K.’s Science and Technology Facilities Council who was not part of the research. “But that’s a big ‘if.’”

    This new flavor would be called “sterile” because the particles would not feel any of the forces of nature, save for gravity, which would effectively block off communication with the rest of the particle world. Even so, they would still have mass, potentially making them an attractive explanation for the mysterious “dark matter” that seems to contribute additional mass to galaxies and galaxy clusters. “If there is a sterile neutrino, it’s not just some extra particle hanging out there, but maybe some messenger to the universe’s ‘dark sector,’” Van de Water says. “That’s why this is really exciting.” Yet the sterile neutrinos that might be showing up at MiniBooNE seem to be too light to account for dark matter themselves—rather they might be the first vanguard of a whole group of sterile neutrinos of various masses. “Once there is one [sterile neutrino], it begs the question: How many?” says Kevork Abazajian, a theoretical physicist at the University of California, Irvine. “They could participate in oscillations and be dark matter.”

    The findings are hard to interpret, however, because if neutrinos are transforming into sterile neutrinos in MiniBooNE, then scientists would expect to measure not just the appearance of extra electron neutrinos, but a corresponding disappearance of the muon neutrinos they started out as, balanced like two sides of an equation. Yet MiniBooNE and other experiments do not see such a disappearance. “That’s a problem, but it’s not a huge problem,” says theoretical physicist André de Gouvêa of Fermilab. “The reason this is not slam-dunk evidence against the sterile neutrino hypothesis is that [detecting] disappearance is very hard. You have to know exactly how much you had at the beginning, and that’s a challenge.”

    Another Mystery?

    Or perhaps MiniBooNE has discovered something big, but not sterile neutrinos. Maybe some other new aspect of the universe is responsible for the unexpected pattern of particles in the experiment’s beam. “Right now people are thinking about whether there are other new phenomena out there that could resolve this ambiguity,” de Gouvêa says. “Maybe the neutrinos have some new force that we haven’t thought about, or maybe the neutrinos decay in some funny way. It kind of feels like we haven’t hit the right hypothesis yet.”

    Unusually, this is one mystery physicists will not have to wait too long to solve. Another experiment at Fermilab called MicroBooNE was designed to follow MiniBooNE and will be able to study the excess more closely.


    One drawback of MiniBooNE is that it cannot be sure the flashes of light it sees are truly coming from neutrinos—it is possible that some unknown process is producing an excess of photons that mimic the neutrino signal. MicroBooNE, which should deliver its first data later this year, can distinguish between neutrino signals and impostors. If the signal turns out to be an excess of ordinary photons, rather than electron neutrinos, then all bets are off. “We don’t know what would do that in terms of physics, but if it is due to photons, we know that this sterile neutrino interpretation is not correct,” de Gouvêa says.

    In addition to MicroBooNE, Fermilab is building two other detectors to sit on the same beam of neutrinos and work in concert to study the neutrino oscillations going on there. Known collectively as the Short-Baseline Neutrino Program, the new system should be up and running by 2020 and could deliver definitive data in the early part of that decade, says Steve Brice, head of Fermilab’s Neutrino Division.

    FNAL Short baseline neutrino detector

    Until then physicists will continue to debate the mysteries of neutrinos—a field that is growing in size and excitement every year. The meeting happening now in Heidelberg, for example, is the largest neutrino conference ever. “It’s been a steady ramp-up over the last decade,” Brice says. “It’s an area that’s hard to study, but it’s proving to be a very fruitful field for physics.”

    See the full article here .


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  • richardmitnick 4:54 pm on December 10, 2017 Permalink | Reply
    Tags: , , , , Bridgmanite, , Could super-Earths host geology similar to Earth’s?, Exogeology, Institute of Laser Engineering Osaka University, Laboratoire d' Optique Appliquee Palaiseau France, , SA, ,   

    From SA: “The Labs That Forge Distant Planets Here on Earth” 

    Scientific American

    Scientific American

    December 10, 2017
    Shannon Hall

    Could super-Earths such as the one depicted here host geology similar to Earth’s? Credit: NASA Ames, JPL-Caltech, T. Pyle

    Yingwei Fei and his colleagues had spent a month carefully crafting the three slivers of dense silicate—shiny and round, each sample was less than a millimetre thick. But in early November, it was time to say goodbye. Fei carefully packed the samples, plus a few back-ups, in foam and shipped them from Washington DC to Albuquerque, New Mexico. There, the Z Pulsed Power Facility at Sandia National Laboratories will soon send 26 million amps surging towards the slivers, zapping them, one by one, into dust.

    Sandia Z machine

    The Z machine can replicate the extreme conditions inside detonating nuclear weapons. But Fei, a high-pressure experimental geologist at the Carnegie Institution for Science’s Geophysical Laboratory in Washington DC, has a more otherworldly goal in mind: he hopes to explore how bridgmanite, a mineral found deep beneath Earth’s surface, would behave at the higher temperatures and pressures found inside larger rocky planets beyond the Solar System.

    The experiment is one small contribution to exogeology: a research area that is bringing astronomers, planetary scientists and geologists together to explore what exoplanets might look like, geologically speaking. For many scientists, exogeology is a natural extension of the quest to identify worlds that could support life. Already, astronomers have discovered thousands of exoplanets and collected some of their vital statistics, including their masses and radii. Those that orbit in the habitable, or ‘Goldilocks’, zone—a region around the host star that is temperate enough for water to exist in liquid form—are thought to be particularly life-friendly.

    But Earth has a lot more going for it than its size, mass and favourable orbit, says Cayman Unterborn, an exogeologist at Arizona State University in Tempe. Its churning molten core, for example, creates and sustains a magnetic field that shields the planet’s fragile atmosphere from the solar wind. And the motion of tectonic plates helps regulate global temperatures, by cycling carbon dioxide between rocks and the atmosphere. Exoplanet discoveries keep pouring in. But astronomers are “just now realizing, ‘Well wait, we want to understand these systems a lot more than just stamp collecting’”, Unterborn says. “Bringing geology into the mix is a natural factor.”

    Researchers are using simulations and experiments, such as Fei’s at the Z machine, to learn what kinds of exoplanet might have Earth-like geology. The work could help researchers prioritize which exoplanets to study.

    But the field faces several challenges, not least that mystery still surrounds much of Earth’s geology—such as how and when tectonic activity first began. “It’s a fundamental discovery that changed geology,” says Richard Carlson, a geochemist at the Carnegie Institution. “But we still don’t know why it works the way it does.” What’s more, confirming that an exoplanet actually boasts Earth-like geology could be difficult; astronomers rarely observe these planets directly, and if they do, the planet might be the size of a single pixel in their image.

    Even indirect evidence—or the smallest suggestion—of geological activity could give researchers a more complete picture of these distant worlds, and which ones are the best candidates to search for indications of life. “It’s like if you came across a giant crime scene with very little evidence,” says Sara Seager, an astrophysicist at the Massachusetts Institute of Technology in Cambridge. “You work your hardest to take what little evidence there was and try to piece it together somehow.”

    Turning outwards

    One of the most exciting targets of exoplanetary science has been super-Earths. These rocky planets—with as many as ten times Earth’s mass—have no parallel in the Solar System. But they are now known to be quite common in the Galaxy and, because many are fairly big, they could make easier targets for detailed observation than Earth-sized planets.

    Early studies of super-Earth geology, published about ten years ago, examined what these planets would look like if they were simply scaled-up versions of Earth. But the scorching-hot planet 55 Cancri e, first spotted in 2004, underscored the idea that super-Earths could be quite different. Observations in 2011 revealed the planet to have roughly twice Earth’s radius and a little more than eight times its mass, yielding an average density only marginally higher than Earth’s—and that presented a conundrum.

    If 55 Cancri e had an iron core and silicate mantle, like Earth, it should be more massive given its size. An ocean wrapped around the whole planet would bring 55 Cancri e’s density down to Earth-like levels. But the planet is too hot for water to survive for long; it orbits so close to its host star that the day-side temperature is roughly 2,500 kelvin.

    A resolution came in 2012, when Nikku Madhusudhan, an astronomer then at Yale University in New Haven, Connecticut, and his colleagues decided to take a fresh approach. Previous research had suggested that the planet’s host star has a much higher ratio of carbon to oxygen than the Sun. Stars and their planets are built from the same swirling disk of dust and gas, so it seemed fair to assume that 55 Cancri e would also be carbon-rich. When Madhusudhan accounted for this carbon in his model of the planet’s interior, it produced a match with the mass and radius of the world. “That was a revelation,” says Madhusudhan, now at the University of Cambridge, UK. And such a world would be truly alien. Madhusudhan suspects that its crust could be dominated by graphite; inside the planet, the pressure would probably crush vast amounts of the element into diamond. “It would look pretty radical compared with what we see in the Solar System,” he says.

    A planet made of diamond would fire up the imagination, although 55 Cancri e’s host star might not actually contain as much carbon as thought. Even if it did, astronomers caution against assuming that a planet’s composition matches that of its host star. Seager notes that this idea wouldn’t account well for the variety of planets in the Solar System. “At this point, it’s a reasonable inference, but I think it’s important to realize that it’s not iron-clad,” says Gregory Laughlin, an astronomer at Yale.


    Exogeologists have embraced this uncertainty, and are trying their best to pin down how distant worlds form and evolve. To get from a list of starting elements to geology, scientists need to know what minerals form, when they melt and how their density changes with pressure and temperature. Those data can be used to simulate how a planet develops from an undifferentiated, molten ball into a layered structure, with minerals forming—and sinking or floating—as the planet cools. “We can build up a mineralogical, let’s say, onion-skin model of what the planet would look like initially,” says Wim van Westrenen, a geologist at the Free University of Amsterdam. Then, he says, researchers can use numerical models to predict how that planet will evolve and whether the migration of materials will be enough to drive plate tectonics.

    To gather information to feed these models, geologists are starting to subject synthetic rocks to high temperatures and pressures to replicate an exoplanet’s innards—as Fei and his colleagues are doing. Although the goal of these experiments is new, the approach is not. For decades, experimental petrologists have built instruments to simulate the conditions of Earth’s interior, anywhere from a few centimetres below the surface to Earth’s core. Many use a device called a diamond anvil cell. This apparatus squeezes materials by pushing the blunted tips of two gem-quality diamonds together. While a sample is under pressure, a laser can be used to heat it. At the same time, experimentalists can bombard the mat­erial with X-rays to investigate its crystalline structure and explore how the material changes as it is pushed to high temperatures and pressures.

    Groups including Sang-Heon Dan Shim, a mineral physicist at Arizona State University, and his colleagues have used this process to squeeze carbon-rich samples that might reflect the composition of 55 Cancri e. The work has revealed how planets dominated by carbon-containing compounds called carbides might transport heat, and how they might differ from planets that, like Earth, are dominated by silicates.

    Carbon is not the only element of interest. Unterborn points to magnesium, silicon and iron as “the big three” that will affect a planet’s bulk structure, influencing how heat flows in the mantle and the relative size of the planet’s core—and so the presence of plate tectonics and a global magnetic field, respectively. Ratios of these elements vary widely in stars. The Sun has one magnesium atom for every silicon atom; in other stars, that ratio ranges from 0.5 to 2. The difference might seem small, but if the same ratios are present in planets, they could drastically affect geology.

    Most textbooks argue that magnesium-rich rocks would be softer than those containing high concentrations of silicon—so much so that walking on a magnesium-rich world might feel like walking on mud. Shim’s diamond-anvil-cell work on rocks with various magnesium-to-silicon ratios suggests these worlds could also boast deeper reservoirs of magma than a silicon-rich planet and, as a result, more catastrophic volcanoes. But Shim notes that other parameters, such as the concentration of water in minerals, must also be taken into account.

    High pressure

    With two diamonds, Shim can apply no more than 400 gigapascals of pressure, a little higher than the pressure in Earth’s core. To probe the interiors of super-Earths, he has turned to the world’s brightest X-ray laser: the Linac Coherent Light Source at SLAC National Accelerator Laboratory in Menlo Park, California.


    The instrument can generate shocks inside the sample, producing pressures as high as 600 giga­pascals—enough to simulate the cores of planets twice as massive as Earth.

    Geologists are also using other large facilities to probe potential exoplanet formulations. The Z machine can reach 1,000 gigapascals—the condition expected inside planets nearly three times Earth’s mass. Laser facilities in Palaiseau, France, and Osaka, Japan, can reach a similar range.

    Laboratoire d’ Optique Appliquee, Palaiseau, France

    Institute of Laser Engineering, Osaka University

    And some researchers have turned to the National Ignition Facility at Lawrence Liver­more National Laboratory in California, which is used to study nuclear fusion and can subject samples to as much as 5,000 giga­pascals, the pressure of Jupiter’s deep interior.


    These experiments are still in their preliminary stages, as researchers compete for time at these facilities and slowly accumulate data on a variety of basic compounds.

    At the end of the day, exogeologists hope to find the right combination of elements to build exoplanets with Earth-like geologies. “I would like to identify the compositional Goldilocks zone,” says Wendy Panero, a geologist at the Ohio State University in Columbus. “What is the not-too-soft, not-too-stiff habitable zone for rock composition?”

    The answer might not be clear-cut. Even perfect knowledge of composition might not tell exogeologists much about the state of a planet. Earth, for example, did not host plate tectonics in its early history, and it is not expected to do so forever. And its neighbour Venus shows how widely planetary evolution can diverge. The planet’s mass, radius, composition and distance from the Sun are similar to those of Earth. But Earth supports life, whereas Venus, swaddled in a haze of carbon dioxide, is quite dead. Stephen Mojzsis, a geologist at the University of Colorado Boulder, suspects that the loss of plate tectonics on Earth will eventually cause it to resemble its super-heated sibling. “It’s inevitable,” he says. “We’re just not sure when that will happen.” So, although most early exoplanet models are focusing on composition, exogeologists might ultimately have to include additional factors such as billions of years of planetary evolution.

    Some expect that this work will help astronomers determine which planets to target in the search for life. If scientists know the conditions needed to sustain a magnetic field for billions of years, or the proportions of elements required to drive convection in the mantle, they could advise their colleagues to scrutinize the worlds that meet those criteria. Then astronomers could turn powerful telescopes, such as NASA’s James Webb Space Telescope, slated to launch in 2019, towards those planets to search their atmospheres for potential signatures of alien life.

    It might also be possible to spot geological activity from a distance. A transient spike in atmospheric sulfur, for example, might be indirect evidence of the presence of an active volcano. Changes in reflectivity as a planet rotates might hint at the presence of continents and oceans, which could also suggest tectonic activity.

    Already, there has been talk of a possible detection of volcanic activity—on 55 Cancri e.

    55 Cancri e

    In 2016, Brice-Olivier Demory, an astronomer at the University of Bern, and his colleagues published the first heat map of the planet, created using NASA’s infrared Spitzer Space Telescope.


    NASA/Spitzer Infrared Telescope

    The planet is tidally locked to its star, so one hemisphere is eternally bathed in sunlight and the other is dark. The planet should be hottest closest to the star, but Demory and his colleagues discovered that the hottest point seems to be offset. They posited that flowing lava is carrying heat away (although more recent work has argued that winds might be responsible instead).

    It’s clear that 55 Cancri e is no place for life. But other worlds may be much more inviting. Earlier this year, Unterborn completed a study that looked at more than 1,000 Sun-like stars. Using their compositions, he determined that one-third of those stars could host planets whose crust was dense enough to sink into the mantle—a process that might let plate tectonics thrive for billions of years.

    Although researchers are just the beginning to explore the geology of exoplanets, Carlson notes that the study of these worlds has already yielded a number of surprises, not least evidence of planets that seem to have undergone dramatic migrations from their original orbits. This discovery caused astronomers to rethink the Solar System’s evolution, and theorize that similar movements could have helped carry materials, such as water ice, to Earth. “I don’t think humans are anywhere near as imaginative and creative as nature is,” Carlson says. “So, understanding the diversity of what’s out there will just open our eyes to other possibilities. And it’s those other possibilities that will help us understand our situation better.”

    See the full article here .

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    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

  • richardmitnick 1:24 pm on August 23, 2017 Permalink | Reply
    Tags: , , , , SA, Strange Dead Star Could Be Remnant of Mini-Supernova   

    From SA: Strange Dead Star Could Be Remnant of Mini-Supernova 

    Scientific American

    Scientific American

    August 23, 2017
    Charles Q. Choi

    Sirius B ( lower left) is the companion the giant star Sirius, and a typical example of a “white dwarf,” a stellar ember left behind by dying Sun-like stars. Astronomers studying the composition and motion of another more distant white dwarf, LP 40-365, have found hints that it instead comes from a different process, a poorly-understood stellar explosion called a “mini-supernova.” Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester)

    A strange dead star may be a remnant of what was essentially a miniature supernova, a new study finds.

    The properties of this bizarre star may help shed light on how the unusual supernova that created it formed, the study’s researchers said.

    The scientists investigated white dwarfs, which are superdense, Earth-size cores of dead stars that are left behind after stars have exhausted their fuel and shed their outer layers.

    “These objects are very faint—much fainter than ordinary stars—but they are numerous in our own corner of the Milky Way,” said study lead author Stephane Vennes, an astrophysicist at the Astronomical Institute of the Czech Academy of Sciences in Ondrejov, Czech Republic.

    Most stars will become white dwarfs one day. Indeed, “our own sun will finish its own life as an unremarkable white dwarf,” Vennes told Space.com.

    Vennes and his colleagues focused on an unusual white dwarf named LP 40-365, which is located about 1,000 light-years from Earth. This object’s mass is about 14 percent of the sun’s mass, and its diameter is about 8 percent of the sun’s. Unusually, it was zipping through space at about 1.23 million mph (1.98 million km/h).

    “It was immediately clear that this was no ordinary star,” Vennes said. “Its velocity is so high that it is on its way to leave permanently the Milky Way.”

    To learn more about the white dwarf, the researchers examined it over the course of two years using the Kitt Peak National Observatory in Arizona, the William Herschel Telescope in Spain’s Canary Islands, the Hiltner Telescope in Arizona and the Gemini North Telescope in Hawaii.

    NOAO Kitt Peak National Observatory on the Tohono O’odham reservation outside Tucson, AZ, USA

    ING 4 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands

    ING 4 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands

    Hiltner Telescope in Arizona

    Gemini/North telescope at Maunakea, Hawaii, USA

    Vennes’ group discovered that not only the speed, but also the composition, of this white dwarf was strange. Unlike many white dwarfs, LP 40-365’s atmosphere lacks any trace of hydrogen and helium, the two most common elements in the universe. Instead, its visible atmosphere is composed almost exclusively of oxygen and neon gas, sprinkled with traces of sodium and magnesium.

    “The unusual white dwarf LP 40-365 is unlike any other white dwarf,” Vennes said.

    Now, Vennes and his colleagues suggest that the origin of this bizarre white dwarf might lie in what is essentially a miniature version of a supernova.

    Supernovas are the most powerful stellar explosions known to scientists; they’re visible all the way to the edge of the universe. The first of the two main flavors, Type Ia supernovas, occur after a white dwarf is completely destroyed after siphoning too much fuel from a companion star. In contrast, Type II supernovas happen after the core of a star about 10 to 100 times as massive as the sun runs out of fuel and collapses into an extraordinarily dense lump in a fraction of a second, blasting luminous radiation outward.

    About 15 years ago, scientists began noticing that a few supernovas appeared to be similar to regular Type Ia supernovas, but were distinctly fainter. Some of these so-called Type Iax supernovas glowed with only 1 percent of the peak luminosity of Type Ia supernovas.

    Previous research suggested that Type Iax outbursts might happen when a white dwarf accumulates fuel from a donor star but the core of the white dwarf fails to completely burn during the supernova. As a result, a giant piece of shrapnel gets kicked into space—”a hypervelocity star,” Vennes said.

    The researchers said LP 40-365 was exactly what one might expect as the leftovers from a Type Iax supernova. Based on the white dwarf’s size and current temperature, they estimated that the explosion happened between 5 million and 50 million years ago. Based on its speed and trajectory, it likely made its closest approach to the sun about 500,000 years ago, coming within about 300 light-years from Earth, the researchers said.

    The new findings may shed light on why a Type Iax supernova occurs, according to Vennes. The atmospheric composition of LP 40-365 favors a model where the white dwarf behind such an explosion has a mantle layer rich in oxygen and neon that influences the way the dead star burned, resulting in a delayed detonation that “leaves a minute amount of core material unburnt,” Vennes said.

    The scientists expect that more high-speed remnants of Type Iax supernovas will be found in the future. “We believe this object is only the first among many that remain to be discovered,” Vennes said. “The European Space Agency mission Gaia should deliver a large number of such candidates.”

    ESA/GAIA satellite

    The scientists detailed their findings in the Aug. 18 issue of the journal Science.

    See the full article here .

    Previously covered here, but this new article offers more material.

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  • richardmitnick 3:51 pm on July 12, 2017 Permalink | Reply
    Tags: , Many deep underground experiments, , , SA,   

    From SA: “Physicists Go Deep in Search of Dark Matter” 

    Scientific American

    Scientific American

    July 11, 2017
    Sarah Scoles

    A laboratory buried nearly a mile beneath South Dakota is at the forefront of a global push for subterranean science.

    A worker gazes into the darkness of the Sanford Underground Research Facility’s “4850 level,” a cavern nearly a mile deep in the Homestake mine that houses state-of-the-art physics experiments. Credit: Sarah Scoles

    The elevator that lowers them 4,850 feet down a mine shaft to a subterranean physics lab isn’t called an elevator, the physicists tell me. It’s called The Cage. It descends at precisely 7:30 A.M.—the same time it leaves the surface every day—and doesn’t wait around for stragglers.

    I show up on time, and prepare to board with a group of scientists. We look identical: in coveralls blinged out with reflective tape, steel-toed boots, an emergency breathing mask and a lamp that clips to the belt and loops over the shoulder.

    An operator opens the big yellow door, directs us inside and then closes The Cage. Soon it begins bumping down at 500 feet per minute. The operator’s headlamp provides the only light, tracing along the timber that lines the shaft. We descend for 10 minutes, silently imagining the weight of the world above us increasing. Water trickling down the shaft’s walls provides an unsettling sound track.

    This place—the Sanford Underground Research Facility (SURF) in Lead, S.D.—hosts experiments that can only be conducted deep under Earth’s surface. Entombed beneath the Black Hills by thousands of feet of solid rock, these experiments are shielded from much of the background radiation that bathes the planet’s surface. Here scientists can more easily detect various elusive cosmic messengers that would otherwise be swamped by the sound and fury at the surface—neutrinos that stream from our sun and from distant exploding stars or other hypothetical particles thought to make up the mysterious dark matter that acts as a hidden hand guiding the growth of galaxies. Such particles are so dim that they’re drowned out aboveground: Looking for them there is a bit like looking for a spotlight shining from the sun’s surface. But these are the very particles scientists must study to understand how our universe came to be. And so, from the depths of Earth where even the very closest star does not shine, they are glimpsing some of the most ancient, distant and cataclysmic aspects of the cosmos.

    This place was not always science-centric: For more than 100 years its labyrinth of deep chambers and drippy, dirt-floored tunnels was a gold mine called Homestake. Today, stripped of much of its precious ore, the facility has become a figurative gold mine for researchers as the U.S.’s premier subterranean lab. This fall SURF will debut a new experiment at the frontiers of physics: CASPAR, which mimics the conditions at the cores of stars where atoms of hydrogen and other light elements fuse to release energy, forming as a by-product the more substantial elements required for building asteroids, planets, mines and mammals. This year physicists are also starting to build equipment for an experiment called LUX–ZEPLIN (LZ), which will try to detect particles of dark matter as soon as 2020.

    Lux Zeplin project at SURF

    It is all part of a trend unfolding around (as well as within) the globe, as scientists construct or repurpose buried infrastructure in places like Minnesota, Japan, Italy, China and Finland to peer deep into the cosmos from deep underground, seeking to learn why the universe is the way it is—and maybe how humans got here at all.

    Inside The Cage, the riders have leaned their heads back against the walls, eyes closed for a quiet moment before work. They look up as the elevator lurches to a stop and the door opens onto a rounded, rocky hallway, covered in netting to protect against rock slides and cave-ins. The light is yellow, with a spectrum not unlike the sun’s.

    “Just another day in paradise,” one of the passengers says as the operator releases us into this alien environment. We walk away from The Cage, our only conduit to the surface, and toward the strange science that—like extreme subterranean organisms that survive without sunlight—can only happen here. (LZ), which will try to detect particles of dark matter as soon as 2020.

    Cosmic Messengers in a Mine

    En route to our first destination, the LZ dark-matter experiment, we walk through a section of the mine called the Davis Lab.

    Its name descends from late physicist Ray Davis, who visited the town of Lead in the 1960s with a science experiment in mind. Back then Lead and next-door Deadwood looked much like they look now, with one-floor casinos and a bar bearing a sign that reads “Historic Site Saloon No. 10 Where Wild Bill Was Shot.” Davis had asked the owners of the Homestake Mine if he could use a small slice of that vast space to search for solar neutrinos.

    Neutrinos are nearly massless particles with no electrical charge. They move almost as fast as light itself. They are barely subject to the effects of gravity and are immune to electromagnetism. In fact, they hardly interact with anything at all—a neutrino might just zip straight through the atoms of any corporeal object in the universe in the way a motorcycle can split lanes straight through traffic. Physicists and astronomers love neutrinos because their cosmic shyness keeps them pristine. Each carries imprints, like birthmarks, from the explosions and radioactive decays that unleashed them on the cosmos. By studying them, scientists can learn about the inner workings of supernovae, the first moments after the big bang, and the seething hearts of stars—including our sun, which is what Davis wanted to investigate. In the 1960s, theorists had already predicted that neutrinos should exist, but no one had yet found them in the physical world.

    The mining company decided to let Davis try to become the first person to do so.

    Toiling away on Homestake’s “4850 level”—the “floor” 4,850 feet below the surface—Davis built a neutrino detector that became operational in 1967.

    Sanford Underground levels

    Over the course of the next quarter century he extracted what he came for: actual neutrinos, not just theoretical ones on paper. As the first person to directly detect the particles—and so prove they existed at all—Davis won the 2002 Nobel Prize. He was one of the first to show that, sometimes, to best connect with deep space, humans have to travel farther from it, deep inside the planet itself.

    During the initial decades of the Davis experiment, the Homestake Mine continued sending a steady stream of gold to the surface, ultimately producing nearly three million pounds of the precious metal during its lifetime—the most of any mine in the Western Hemisphere. But in 2002 when the price of an ounce dropped too low for the mine to turn a profit, Barrick Gold Corp. shut it down and later donated the facility to the State of South Dakota.

    The state—with funding from billionaire T. Denny Sanford and the U.S. Department of Energy—expanded on Davis’s legacy and turned the whole operation into a physics lab: today’s SURF, with the original Davis Campus at its core.

    Setting Up Shop

    As we enter the Davis Campus, we snap elastic-ankle booties over our shoes and are gifted a sticker. “It’s always sunny on the 4850,” it says. The evidence does not support this conclusion.

    Our guide, Mark Hanhardt, doesn’t have such a sticker, but he does have a Ghostbusters patch on the upper arm of his coveralls. He later refers to the dark matter that LZ will look for as “ghost particles.” He is, then, the buster to which his patch refers. He’s a jolly guy, with a smile—the eyes-and-mouth kind—always in between his beard and short haircut. An experiment-support scientist, he is also the son of a former Homestake miner called Jim Hanhardt. Jim was laid off when Homestake stopped mining—but he got a different belowground job back when SURF took over, becoming a technical support lead in 2008. For a few years, before his father’s recent death, the two toiled together in this subterranean space—a common story around Lead. Everyone in town seems to know or share blood with someone who works in the lab, because SURF hired back many miners and contracted with local companies for blasting and construction work. Hanhardt’s daily work, then, is carrying on dual legacies—one familial, one scientific. “There’s already been one Nobel from down here,” Hanhardt says, gesturing for us to follow him down the hallway. “Maybe there will be more.”

    Hanhardt walks along the platform toward the high-ceilinged room that SURF employees are currently preparing for LUX-ZEPLIN. Most of the space belongs to an immense and empty water tank—three and a half times as tall as me, and across whose diameter four and a half of me could lie down.

    SURF LUX water tank was transported in pieces and welded together in the Davis Cavern

    Hanhardt calls it the “giant science bucket.” Once it had been filled with 72,000 gallons of water and shielded an experiment called LUX, which operated from October 2014 to May 2016. At the time LUX was the world’s most sensitive seeker of dark matter—more attuned to the universe’s most mysterious particles than any other experiment on the planet.

    Decades of observations with telescopes have hinted the universe is full of invisible matter that neither emits nor reflects light but outweighs all the visible stars, gas and galaxies combined. This dark matter has apparently shaped some of those galaxies into spirals, and may even be what made their matter glom together into galaxies in the first place. No one knows exactly what the dark matter is made of, but most physicists agree it is likely composed of at least one kind of undiscovered subatomic particle. But just as one cannot say for sure what Sasquatch looks like until you spy one on a remote camera or ensnare one in a trap, scientists can’t say what dark matter is until they capture some.

    LUX tried to do just that. During its nearly yearlong run, a 350-kilogram canister of liquid xenon sat nested like a matryoshka doll inside the giant water tank, which isolated the xenon from the intrepid background of run-of-the-mill cosmic rays that manage to penetrate even this far underground. The xenon, denser than solid aluminum, waited hopefully for hypothetical dark matter particles to tunnel through thousands of feet of earth, ending up in South Dakota after their interstellar—or even intergalactic—journeys. If a particle of dark matter struck an atom of xenon, the collision would produce a flash of light. Electrons would then spin out of the collision, making a second flash. Detectors lining the tank’s interior would pick those up and send a signal back to scientists, who could rewind the reaction to study the particles that first sparked the fireworks.

    In October 2016 SURF scientists began dismantling LUX and carting its xenon, like miners, to the surface. The setup had seen nothing. Dark matter had stayed true to its name.

    To tenacious physicists, that just meant they needed a bigger, better bucket in which to collect dark matter: LUX-ZEPLIN. When it debuts in 2020, this follow-on experiment will still be the best in the world: 70 times as sensitive as its predecessor, thanks in large part to its 10 metric tons of liquid xenon—as compared with LUX the First’s puny third of a metric ton. The scientific collaboration, which involves 250 scientists from the U.S., the U.K., Portugal, Russia and South Korea, launched construction in February.

    Hanhardt sticks his head inside the silvery cylinder of the empty water tank and whispers “Helloooo.” The tiny sound seems to echo almost endlessly, bouncing on the tank walls and throwing itself back at us as evidence of his existence.

    Deep Physics

    SURF occupies one of the world’s deepest scientific spaces, more than twice as far down as the Soudan Underground Laboratory in Minnesota, which is in a former iron mine.

    Soudan Underground Laboratory in Minnesota.Alamy photos

    The Super-Kamiokande lab, which focuses on neutrinos like Davis did, occupies the Mozumi zinc mine in Japan, 3,300 feet underground.

    Super-Kamiokande experiment. located under Mount Ikeno near the city of Hida, Gifu Prefecture, Japan

    The deepest physics facility in the world, though, is China’s Jinping Lab, in Sichuan, China which takes advantage of the tunnels beneath a hydroelectric dam.


    It has a dark matter detector and a neutrino experiment called PandaX.


    Using existing infrastructure, as these labs do, means scientists can focus on building their experiments instead of blasting rock. And it means they can rely on local workers who already know how to help maintain the snaking caverns that might otherwise flood, collapse or fill with poisonous gases. Italy is the first country to complete a belowground lab, Gran Sasso, for the express purpose of doing research. It took them 30 years.

    Gran Sasso LABORATORI NAZIONALI del GRAN SASSO, located in the Abruzzo region of central Italy

    Each of these far-flung facilities is racng to be the first to make breakthrough discoveries about elusive dark matter and ghostly neutrinos. But for the end-result science to emerge at its best, the facilities need one another—and one another’s data—to be better, faster and stronger than they can manage on their own. Together, they form an ecosystem that supports science that can’t be done on the surface.

    A Pint-Size Star Is Born

    SURF, since its genesis, has been expanding beyond the Davis Campus to other parts of the mine—of which there are plenty. The new “campus” is so far away that to visit it we take a railway cart, rumbling down darkened tracks through cavernous spaces like pickax-wielders of old. Cool air still blows past us, somehow flowing into this nether realm fresh from the surface world almost a mile above. Hallway lights pass at intervals, glowing then receding in slow, strobelike procession until we reach what is called the Ross Campus and the CASPAR experiment.

    CASPAR’s accelerator at SURF

    CASPAR is a particle accelerator—but one that fits in a regular-size room. A series of tubes, the air sucked from them by vacuum pumps, snakes across tables that run all the way across the room, then bend back into a farther open space. From one end a beam of particles streams through the tubes, its path bent by magnets. At the other end sits a target. When the beam bull’s-eyes it, the collision triggers the fusion processes that happen inside stars, when small atoms join to build larger ones. These processes happen deep inside stellar cores all across the universe, and have created essentially all the elements heavier than helium (elements astronomers call “metals,” even when they are not down in mines).

    All those “metals” comprise you, me, these tubes, this cavity, SURF, the ecosystem of underground labs, Earth and everything you may (or may not) care about. But scientists do not actually understand the details of how stars fuse elements. And because they cannot fly into the center of a star, they have instead traveled toward the center of the planet. Here, shielded from stray radiation and particles that bombard Earth’s surface, they can much more clearly see the particles and radiation from their own experiment, rather than from the sun or space.

    When we arrive, a batch of graduate students and three professors are huddled over several computers, trying to get that beam as just-right as it can be. The mini accelerator itself is on the other side of a door next to them. It looks like a kid’s chemistry set, minus the colorful liquids.

    Physicist Michael Wiescher, from the University of Notre Dame, steps away from his colleagues to tell me what they are doing. He speaks quietly, perhaps trying not to disturb them. He needn’t worry, though: Their attention is as focused as the experiment’s beam.

    That’s because it’s a big day down here: Wiescher and the others, from Notre Dame and the South Dakota School of Mines, are just starting to launch the beam toward their target. Soon they will make their own pint-size stars, farther from outer space than most people ever go. Their first experiments will examine the details of a process called “helium burning.” In the burning’s first stage, an important interaction happens when three helium nuclei alchemize into one carbon—the atom that by definition makes molecules “organic.” In actual stars this only happens with age: After stars like the sun have burned through most of the hydrogen fuel at their cores, and have evolved into red giant stars, they begin to fuse helium instead. But here in SURF, in a bathroom-size setup, CASPAR can learn about burning helium any day the scientists see fit, and so learn how to create again and again the elements that became us—fast-forwarding the sun’s clock while rewinding our own. “It’s not just physics,” says Hanhardt, who stands watch as the team works, “It’s philosophy.” It deals, in other words, in the big questions: How, literally, did we get here? Why, cosmically? These queries have scientific answers but existential implications, the science having moved into territory previously only occupied by religion.

    European researchers, Wiescher tells me, are two years behind in their work on a similar project called LUNA–MV at Gran Sasso.

    LUNA–MV at Gran Sasso

    China is building its own—JUNA. But CASPAR will (any day now) start cooking first. After the CASPAR team gets a few results on their own, they plan to merge data with some of these other teams, and will let scientists come down to this cave to do their own experiments with the CASPAR equipment. Someday soon—when CASPAR opens up for collaborators, when LZ begins its search—SURF will be robust and bustling in the way of the gold mine’s heyday, back when a single neutrino experiment squatted in a corner.

    One of the computer-focused scientists says, “We have 100 percent beam transmission!” and then a smiling grad student—Thomas Kadlecek, from the South Dakota School of Mines—turns to me and Wiescher. He likes it down here, he says. His grandfather was a miner back when it was Homestake. With that, he quickly turns away again goes back to his work, leaning on a rack of electronics.

    I later find out his grandfather died in Homestake. Just as one generation of stars fuels the next—South Dakota’s previous underground generations inspire the ones that follow. “They identify with the mine,” Wiescher explains. “It’s incredible.”

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  • richardmitnick 10:13 am on July 10, 2017 Permalink | Reply
    Tags: , , , , Personalized cancer vaccines, Personalized Cancer Vaccines Vanquish Melanoma in Small Study, SA   

    From SA: “Personalized Cancer Vaccines Vanquish Melanoma in Small Study” 

    Scientific American

    Scientific American

    July 6, 2017
    Sharon Begley

    The therapy trains the immune system to attack tumors.

    Metastatic melanoma cells. Credit: NIH Wikimedia

    A small pilot study raises hopes that personalized cancer vaccines might prove safer and more effective than immune-based therapies already in use or further along in development. In a paper published online in Nature on Wednesday, scientists reported that all six melanoma patients who received an experimental, custom-made vaccine seemed to benefit: their tumors did not return after treatment.

    Researchers not involved in the study praised its results, but with caveats. The scientists “did a beautiful job,” said MD Anderson Cancer Center’s Greg Lizee, an expert in tumor immunology, who called the results “very encouraging.” But because the study did not include a comparison group of patients who received standard treatment and not the vaccine, he cautioned, “it’s not completely proved yet that the lack of [cancer] recurrence was due to the vaccine.”

    See the full article here .

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  • richardmitnick 11:23 am on July 1, 2017 Permalink | Reply
    Tags: Entanglement and quantum interference, , Now an interface based on the popular programming language Python, , , SA, Supercomputers still rule   

    From SA: “Quantum Computing Becomes More Accessible” 

    Scientific American

    Scientific American

    June 26, 2017
    Dario Gil

    Credit: World Economic Forum

    Quantum computing has captured imaginations for almost 50 years. The reason is simple: it offers a path to solving problems that could never be answered with classical machines. Examples include simulating chemistry exactly to develop new molecules and materials and solving complex optimization problems, which seek the best solution from among many possible alternatives. Every industry has a need for optimization, which is one reason this technology has so much disruptive potential.

    Until recently, access to nascent quantum computers was restricted to specialists in a few labs around the world. But progress over the past several years has enabled the construction of the world’s first prototype systems that can finally test out ideas, algorithms and other techniques that until now were strictly theoretical.

    Quantum computers tackle problems by harnessing the power of quantum mechanics. Rather than considering each possible solution one at a time, as a classical machine would, they behave in ways that cannot be explained with classical analogies. They start out in a quantum superposition of all possible solutions, and then they use entanglement and quantum interference to home in on the correct answer—processes that we do not observe in our everyday lives. The promise they offer, however, comes at the cost of them being difficult to build. A popular design requires superconducting materials (kept 100 times colder than outer space), exquisite control over delicate quantum states and shielding for the processor to keep out even a single stray ray of light.

    Existing machines are still too small to fully solve problems more complex than supercomputers can handle today. Nevertheless, tremendous progress has been made. Algorithms have been developed that will run faster on a quantum machine. Techniques now exist that prolong coherence (the lifetime of quantum information) in superconducting quantum bits by a factor of more than 100 compared with 10 years ago. We can now measure the most important kinds of quantum errors. And in 2016 IBM provided the public access to the first quantum computer in the cloud—the IBM Q experience—with a graphical interface for programming it and now an interface based on the popular programming language Python. Opening this system to the world has fueled innovations that are vital for this technology to progress, and to date more than 20 academic papers have been published using this tool. The field is expanding dramatically. Academic research groups and more than 50 start-ups and large corporations worldwide are focused on making quantum computing a reality.

    With these technological advancements and a machine at anyone’s fingertips, now is the time for getting “quantum ready.” People can begin to figure out what they would do if machines existed today that could solve new problems. And many quantum computing guides are available online to help them get started.

    There are still many obstacles. Coherence times must improve, quantum error rates must decrease, and eventually, we must mitigate or correct the errors that do occur. Researchers will continue to drive innovations in both the hardware and software. Investigators disagree, however, over which criteria should determine when quantum computing has achieved technological maturity. Some have proposed a standard defined by the ability to perform a scientific measurement so obscure that it is not easily explained to a general audience. I and others disagree, arguing that quantum computing will not have emerged as a technology until it can solve problems that have commercial, intellectual and societal importance. The good news is, that day is finally within our sights.

    See the full article here .

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  • richardmitnick 4:15 pm on June 29, 2017 Permalink | Reply
    Tags: , , , SA, The Case for Cosmic Modesty,   

    From SA: “The Case for Cosmic Modesty” 

    Scientific American

    Scientific American

    June 28, 2017
    Abraham Loeb

    The Parkes radio telescope in Australia has been used to search for extraterrestrial intelligence. Credit: Ian Sutton Flickr (CC BY-SA 3.0)

    “There are many reasons to be modest,” my mother used to say when I was a kid. But after three decades as an astronomer, I can add one more reason: the richness of the universe around us.

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Prior to the development of modern astronomy, humans tended to think the physical world centered on us. The sun and the stars were thought to revolve around Earth. Although naive in retrospect, this is a natural starting point. When my daughters were infants, they tended to think the world centered on them. Their development portrayed an accelerated miniature of human history. As they grew up, they matured and acquired a more balanced perspective.

    Similarly, observing the sky makes us aware of the big picture and teaches us modesty. We now know we are not at the center of the physical universe, because Earth orbits the sun, which circles around the center of the Milky Way Galaxy, which itself drifts with a peculiar velocity of ~0.001c (c is the speed of light) relative to the cosmic rest frame.

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Many people, however, still believe we might be at the center of the biological universe; namely, that life is rare or unique to Earth. In contrast, my working hypothesis, drawn from the above example of the physical universe, is that we are not special in general, not only in terms of our physical coordinates but also as a form of life. Adopting this perspective implies we are not alone. There should be life out there in both primitive and intelligent forms. This conclusion, implied by the principle of “cosmic modesty,” has implications. If life is likely to exist elsewhere, we should search for it in all of its possible forms.

    Breakthrough Listen Project


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

    GBO radio telescope, Green Bank, West Virginia, USA

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    Breakthrough Starshot Initiative

    Breakthrough Starshot

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    SPACEOBS, the San Pedro de Atacama Celestial Explorations Observatory is located at 2450m above sea level, north of the Atacama Desert, in Chile, near to the village of San Pedro de Atacama and close to the border with Bolivia and Argentina

    SNO Sierra Nevada Observatory is a high elevation observatory 2900m above the sea level located in the Sierra Nevada mountain range in Granada Spain and operated maintained and supplied by IAC

    Teide Observatory in Tenerife Spain, home of two 40 cm LCO telescopes

    Observatori Astronòmic del Montsec (OAdM), located in the town of Sant Esteve de la Sarga (Pallars Jussà), 1,570 meters on the sea level

    Bayfordbury Observatory,approximately 6 miles from the main campus of the University of Hertfordshire

    Our civilization has reached an important milestone. We now have access to unprecedented technologies in our search for extraterrestrial life, be it primitive or intelligent. The search for primitive life is currently underway and well funded, but the search for intelligence is out of the mainstream of federal funding agencies. This should not be the case given that the only planet known to host life, Earth, shows both primitive and intelligent life forms of it.

    Our first radio signals have leaked by now out to a distance of more than 100 light-years and we might soon hear back a response. Rather than being guided by Fermi’s paradox: “Where is everybody?” or by philosophical arguments about the rarity of intelligence, we should invest funds in building better observatories and searching for a wide variety of artificial signals in the sky. Civilizations at our technological level might produce mostly weak signals. For example, a nuclear war on the nearest planet outside the solar system would not be visible even with our largest telescopes.

    But very advanced civilizations could potentially be detectable out to the edge of the observable universe through their most powerful beacons. The evidence for an alien civilization might not be in the traditional form of radio communication signals. Rather, it could involve detecting artifacts on planets via the spectral edge from solar cells, industrial pollution of atmospheres, artificial lights or bursts of radiation from artificial beams sweeping across the sky.

    Finding the answer to the important question: “Are we alone?” will change our perspective on our place in the universe and will open new interdisciplinary fields of research, such as astrolinguistics (how to communicate with aliens), astropolitics (how to negotiate with them for information), astrosociology (how to interpret their collective behavior), astroeconomics (how to trade space-based resources) and so on. We could shortcut our own progress by learning from civilizations that benefited from a head start of billions of years.

    There is no doubt that noticing the big picture taught my young daughters modesty. Similarly, the Kepler space telescope survey of nearby stars allowed astronomers to infer there are probably more habitable Earth-mass planets in the observable volume of the universe than there are grains of sand on all beaches on Earth. Emperors or kings who boasted after conquering a piece of land on Earth resemble an ant that hugs with great pride a single grain of sand on the landscape of a huge beach.

    Just over the past year, astronomers discovered a potentially habitable planet, Proxima b, around the nearest star, Proxima Centauri as well as three potentially habitable planets out of seven around another nearby star TRAPPIST-1.

    ESO Pale Red Dot project

    ESO Red Dots Campaign

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile interior

    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile

    (And if life formed on one of the three, it was likely transferred to the others.) These dwarf stars, whose masses are 12 percent and 8 percent the sun’s mass, respectively, will live for up to 10 trillion years, about a thousand times longer than the sun. Hence, they provide excellent prospects for life in the distant future, long after the sun will die and turn into a cool white dwarf.

    I therefore advise my wealthy friends to buy real estate on Proxima b, because its value will likely go up dramatically in the future. But this also raises an important scientific question: “Is life most likely to emerge at the present cosmic time near a star like the sun?” By surveying the habitability of the universe throughout cosmic history from the birth of the first stars 30 million years after the big bang to the death of the last stars in 10 trillion years, one reaches the conclusion that unless habitability around low-mass stars is suppressed, life is most likely to exist near red dwarf stars like Proxima Centauri or TRAPPIST-1 trillions of years from now.

    The chemistry of “life as we know it” requires liquid water, but being at the right distance from the host star for achieving a comfortable temperature on the planet’s surface is not a sufficient condition for life. The planet also needs to have an atmosphere. In the absence of an external atmospheric pressure, warming by starlight would transform water ice directly into gas rather than a liquid phase.

    The warning sign can be found next door: Mars has a tenth of Earth’s mass and lost its atmosphere. Does Proxima b have an atmosphere? If so, the atmosphere and any surface ocean it sustains will moderate the temperature contrast between its permanent day and night sides. The James Webb Space Telescope, scheduled for launch in October 2018, will be able to distinguish between the temperature contrast expected if Proxima b is bare rock compared with the case where its climate is moderated by an atmosphere, possibly along with an ocean.

    A cosmic perspective about our origins would also contribute to a balanced worldview. The heavy elements that assembled to make Earth were produced in the heart of a nearby massive star that exploded. A speck of this material takes form as our body during our life but then goes back to Earth (with one exception, namely the ashes of Clyde Tombaugh, the discoverer of Pluto, which were put on the New Horizons spacecraft and are making their way back to space).

    What are we then, if not just a transient shape that a speck of material takes for a brief moment in cosmic history on the surface of one planet out of so many? Despite all of this, life is still the most precious phenomenon we treasure on Earth. It would be amazing if we find evidence for “life as we know it” on the surface of another planet, and even more remarkable if our telescopes will trace evidence for an advanced technology on an alien spacecraft roaming through interstellar space.

    References, some with links, some without links.

    Lingam, M. & Loeb, A. 2017, ApJ 837, L23-L28.

    Lingam, M. & Loeb, A. 2017, MNRAS (in the press); preprint available at https://arxiv.org/abs/1702.05500

    Lin, H., Gonzalez, G. A. & Loeb, A., 2014, ApJ 792, L7-L11.

    Loeb, A. & Turner, E. L. 2012, Astrobiology 12, 290-290.

    Guillochon, J. & Loeb, A. ApJ 811, L20-L26.

    Anglada-Escude’, G. et al. 2016, Nature 536, 437-440.

    Gillon, M. et al. 2016, Nature 542, 456-460.

    Lingam, M. & Loeb, A. 2017, PNAS (in the press); preprint available at https://arxiv.org/abs/1703.00878

    Loeb, A., Batista, R. A., & Sloan, D. 2016, JCAP 8, 40-52.

    Kreidberg, L. & Loeb, A. 2016, ApJ, 832, L12-L18.

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  • richardmitnick 11:37 am on June 29, 2017 Permalink | Reply
    Tags: For Apple and every other phone company software became much more important than hardware, Inventing mobile apps, iPhone, SA, The iPhone a full-fledged hand-held computer that could also make calls and browse the internet, The iPhone transformed the mobile phone business the internet economy and in many ways society as a whole, Top-line Nokia phones had more memory better cameras and faster mobile connectivity   

    From SA: “Understanding the Real Innovation behind the iPhone” 

    Scientific American

    Scientific American

    June 29, 2017
    Kalle Lyytinen

    The first iPhone was more a hand-held computer than anything else. Credit: Paul J. Richards Getty Images

    When the iPhone emerged in 2007, it came with all the promise and pomp of a major Steve Jobs announcement, highlighting its user interface and slick design as key selling points. We know now that the iPhone transformed the mobile phone business, the internet economy and, in many ways, society as a whole. But technically speaking, the iPhone was not very innovative.

    Its software and the interface idea were based on the iPod, which was already reinventing the digital music industry. Touchscreens had appeared on earlier phone and tablet models, including Apple’s own Newton. And top-line Nokia phones had more memory, better cameras and faster mobile connectivity. What made the iPhone transformative was the shift in concept underpinning the entire iPhone project: Its designers did not create a telephone with some extra features, but rather a full-fledged hand-held computer that could also make calls and browse the internet.

    As a scholar of management, design and innovation, I find it hard to predict what the next truly revolutionary technological development will be. In the 10 years since the launch of the iPhone, so much about modern life, commerce and culture has changed. In part that’s because the iPhone, and the smartphone boom it spurred, created a portable personal technology infrastructure that’s almost infinitely expandable. The iPhone changed the game not because of its initial technology and cool user interface but rather as a result of its creators’ imagination and courage.

    Inventing mobile apps

    As the iPhone took shape, its designers found themselves torn between making a phone or a computer. Engineers and marketing executives alike worried the new device would kill the iPod market that had driven Apple’s corporate resurgence for five years. Nokia, the biggest player in the cellphone market at the time, had similar technologies and prototypes, and also feared outcompeting its own successful mobile phone product lines that used a simpler and more old-fashioned software platform than that on which iPhone was built.

    Apple took the leap, however, by installing a fully capable computer operating system on the iPhone, along with a few small application programs. Some were phone-related, including a program that handled making and receiving calls, as well as a new way to display voicemail messages, and a system that kept different contacts’ text messages separate. Others were more computer-like, including an email app and a web browser. Of course, the music-playing features from the iPod were included too, linking the phone with the emerging Apple music ecosystem.

    Initially, that was about it for apps. But skilled computer engineers and hackers knew they were holding a palm-sized computer, and set to work writing their own software and getting it running on their iPhones. That was the dawn of the now-ubiquitous app. Within a year, these apps were so popular, and their potential so significant, that Apple’s second version of the iPhone operating system made it easy (and legal) for users to install apps on their phones.

    Shifting priorities

    The prospect of making a fully functional hand-held computer changed how users and manufacturers alike thought about mobile phones. For Apple and every other phone company, software became much more important than hardware. What apps a phone could run, and how quickly, mattered much more than whether it had a slightly better camera or could hold a few more photos; whether it flipped open, slid open or was a bar-style; or whether it had a large keyboard or a small one. The iPhone’s keyboard was on-screen and software-generated, making a function that had required dedicated hardware into one running on generic hardware and dedicated software.

    At the time of the iPhone launch, Nokia offered about 200 different phone styles to meet all the different needs of its hundreds of millions of customers. There was just one iPhone model at the start, and in the ensuing decade there have been only 14 major styles – though today they come in different colors, not just white and black as the original did. This is the power of software functionality and related simplicity.

    The heightened importance of software on a mobile phone shifted the industry’s economy as well. The money came now not just from selling devices and phone services, but also from marketing and selling apps and in-app advertisements. App developers must share revenue with the companies that control smartphones’ operating systems, providing serious earning power: Apple holds about 15 percent of the mobile phone market, but reaps 80 percent of global smartphone profits.

    Whatever the next tech industry game-changer is, and whenever it arrives, it will likely have some connection to the smartphone and related infrastructure. Even today, exploring virtual reality requires only installing an app and connecting just a bit of additional hardware to an existing phone. Similarly, smartphone interfaces and cameras already monitor and control intelligent and automated homes. Even as devices are developed to operate all around us, and even in our clothes, many of them will be able to point to the iPhone as a conceptual ancestor and inspiration.

    See the full article here .

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    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

  • richardmitnick 6:04 pm on June 20, 2017 Permalink | Reply
    Tags: , , , SA   

    From SA: “World’s Most Powerful Particle Collider Taps AI to Expose Hack Attacks” 

    Scientific American

    Scientific American

    June 19, 2017
    Jesse Emspak

    A general view of the CERN Computer / Data Center and server farm. Credit: Dean Mouhtaropoulos Getty Images

    Thousands of scientists worldwide tap into CERN’s computer networks each day in their quest to better understand the fundamental structure of the universe. Unfortunately, they are not the only ones who want a piece of this vast pool of computing power, which serves the world’s largest particle physics laboratory. The hundreds of thousands of computers in CERN’s grid are also a prime target for hackers who want to hijack those resources to make money or attack other computer systems. But rather than engaging in a perpetual game of hide-and-seek with these cyber intruders via conventional security systems, CERN scientists are turning to artificial intelligence to help them outsmart their online opponents.

    Current detection systems typically spot attacks on networks by scanning incoming data for known viruses and other types of malicious code. But these systems are relatively useless against new and unfamiliar threats. Given how quickly malware changes these days, CERN is developing new systems that use machine learning to recognize and report abnormal network traffic to an administrator. For example, a system might learn to flag traffic that requires an uncharacteristically large amount of bandwidth, uses the incorrect procedure when it tries to enter the network (much like using the wrong secret knock on a door) or seeks network access via an unauthorized port (essentially trying to get in through a door that is off-limits).

    CERN’s cybersecurity department is training its AI software to learn the difference between normal and dubious behavior on the network, and to then alert staff via phone text, e-mail or computer message of any potential threat. The system could even be automated to shut down suspicious activity on its own, says Andres Gomez, lead author of a paper [Intrusion Prevention and Detection in GridComputing – The ALICE Case] describing the new cybersecurity framework.

    CERN’s Jewel

    CERN—the French acronym for the European Organization for Nuclear Research lab, which sits on the Franco-Swiss border—is opting for this new approach to protect a computer grid used by more than 8,000 physicists to quickly access and analyze large volumes of data produced by the Large Hadron Collider (LHC).


    CERN/LHC Map

    CERN LHC Tunnel

    CERN LHC particles

    The LHC’s main job is to collide atomic particles at high-speed so that scientists can study how particles interact. Particle detectors and other scientific instruments within the LHC gather information about these collisions, and CERN makes it available to laboratories and universities worldwide for use in their own research projects.

    The LHC is expected to generate a total of about 50 petabytes of data (equal to 15 million high-definition movies) in 2017 alone, and demands more computing power and data storage than CERN itself can provide. In anticipation of that type of growth the laboratory in 2002 created its Worldwide LHC Computing Grid, which connects computers from more than 170 research facilities across more than 40 countries. CERN’s computer network functions somewhat like an electrical grid, which relies on a network of generating stations that create and deliver electricity as needed to a particular community of homes and businesses. In CERN’s case the community consists of research labs that require varying amounts of computing resources, based on the type of work they are doing at any given time.

    Grid Guardians

    One of the biggest challenges to defending a computer grid is the fact that security cannot interfere with the sharing of processing power and data storage. Scientists from labs in different parts of the world might end up accessing the same computers to do their research if demand on the grid is high or if their projects are similar. CERN also has to worry about whether the computers of the scientists’ connecting into the grid are free of viruses and other malicious software that could enter and spread quickly due to all the sharing. A virus might, for example, allow hackers to take over parts of the grid and use those computers either to generate digital currency known as bitcoins or to launch cyber attacks against other computers. “In normal situations, antivirus programs try to keep intrusions out of a single machine,” Gomez says. “In the grid we have to protect hundreds of thousands of machines that already allow” researchers outside CERN to use a variety of software programs they need for their different experiments. “The magnitude of the data you can collect and the very distributed environment make intrusion detection on [a] grid far more complex,” he says.

    Jarno Niemelä, a senior security researcher at F-Secure, a company that designs antivirus and computer security systems, says CERN’s use of machine learning to train its network defenses will give the lab much-needed flexibility in protecting its grid, especially when searching for new threats. Still, artificially intelligent intrusion detection is not without risks—and one of the biggest is whether Gomez and his team can develop machine-learning algorithms that can tell the difference between normal and harmful activity on the network without raising a lot of false alarms, Niemelä says.

    CERN’s AI cybersecurity upgrades are still in the early stages and will be rolled out over time. The first test will be protecting the portion of the grid used by ALICE (A Large Ion Collider Experiment)—a key LHC project to study the collisions of lead nuclei. If tests on ALICE are successful, CERN’s machine learning–based security could then be used to defend parts of the grid used by the institution’s six other detector experiments.

    See the full article here .

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    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

  • richardmitnick 1:27 pm on June 18, 2017 Permalink | Reply
    Tags: , China has taken the leadership in quantum communication, China Shatters 'Spooky Action at a Distance' Record, For now the system remains mostly a proof of concept, Global quantum communication is possible and will be achieved in the near future, , Preps for Quantum Internet, , , SA   

    From SA: “China Shatters ‘Spooky Action at a Distance’ Record, Preps for Quantum Internet” 

    Scientific American

    Scientific American

    June 15, 2017
    Lee Billings

    Credit: Alfred Pasieka Getty Images

    In a landmark study, a team of Chinese scientists using an experimental satellite has tested quantum entanglement over unprecedented distances, beaming entangled pairs of photons to three ground stations across China—each separated by more than 1,200 kilometers. The test verifies a mysterious and long-held tenet of quantum theory, and firmly establishes China as the front-runner in a burgeoning “quantum space race” to create a secure, quantum-based global communications network—that is, a potentially unhackable “quantum internet” that would be of immense geopolitical importance. The findings were published Thursday in Science.

    “China has taken the leadership in quantum communication,” says Nicolas Gisin, a physicist at the University of Geneva who was not involved in the study. “This demonstrates that global quantum communication is possible and will be achieved in the near future.”

    The concept of quantum communications is considered the gold standard for security, in part because any compromising surveillance leaves its imprint on the transmission. Conventional encrypted messages require secret keys to decrypt, but those keys are vulnerable to eavesdropping as they are sent out into the ether. In quantum communications, however, these keys can be encoded in various quantum states of entangled photons—such as their polarization—and these states will be unavoidably altered if a message is intercepted by eavesdroppers. Ground-based quantum communications typically send entangled photon pairs via fiber-optic cables or open air. But collisions with ordinary atoms along the way disrupt the photons’ delicate quantum states, limiting transmission distances to a few hundred kilometers. Sophisticated devices called “quantum repeaters”—equipped with “quantum memory” modules—could in principle be daisy-chained together to receive, store and retransmit the quantum keys across longer distances, but this task is so complex and difficult that such systems remain largely theoretical.

    “A quantum repeater has to receive photons from two different places, then store them in quantum memory, then interfere them directly with each other” before sending further signals along a network, says Paul Kwiat, a physicist at the University of Illinois in Urbana–Champaign who is unaffiliated with the Chinese team. “But in order to do all that, you have to know you’ve stored them without actually measuring them.” The situation, Kwiat says, is a bit like knowing what you have received in the mail without looking in your mailbox or opening the package inside. “You can shake the package—but that’s difficult to do if what you’re receiving is just photons. You want to make sure you’ve received them but you don’t want to absorb them. In principle it’s possible—no question—but it’s very hard to do.”

    To form a globe-girdling secure quantum communications network, then, the only available solution is to beam quantum keys through the vacuum of space then distribute them across tens to hundreds of kilometers using ground-based nodes. Launched into low Earth orbit in 2016 and named after an ancient Chinese philosopher, the 600-kilogram “Micius” satellite is China’s premiere effort to do just that, and is only the first of a fleet the nation plans as part of its $100-million Quantum Experiments at Space Scale (QUESS) program.

    Micius carries in its heart an assemblage of crystals and lasers that generates entangled photon pairs then splits and transmits them on separate beams to ground stations in its line-of-sight on Earth. For the latest test, the three receiving stations were located in the cities of Delingha and Ürümqi—both on the Tibetan Plateau—as well as in the city of Lijiang in China’s far southwest. At 1,203 kilometers, the geographical distance between Delingha and Lijiang is the record-setting stretch over which the entangled photon pairs were transmitted.

    For now the system remains mostly a proof of concept, because the current reported data transmission rate between Micius and its receiving stations is too low to sustain practical quantum communications. Of the roughly six million entangled pairs that Micius’s crystalline core produced during each second of transmission, only about one pair per second reached the ground-based detectors after the beams weakened as they passed through Earth’s atmosphere and each receiving station’s light-gathering telescopes. Team leader Jian-Wei Pan—a physicist at the University of Science and Technology of China in Hefei who has pushed and planned for the experiment since 2003—compares the feat with detecting a single photon from a lone match struck by someone standing on the moon. Even so, he says, Micius’s transmission of entangled photon pairs is “a trillion times more efficient than using the best telecommunication fibers. … We have done something that was absolutely impossible without the satellite.” Within the next five years, Pan says, QUESS will launch more practical quantum communications satellites.

    Although Pan and his team plan for Micius and its nascent network of sister satellites to eventually distribute quantum keys, their initial demonstration instead aimed to achieve a simpler task: proving Einstein wrong.

    Einstein famously derided as “spooky action at a distance” one of the most bizarre elements of quantum theory—the way that measuring one member of an entangled pair of particles seems to instantaneously change the state of its counterpart, even if that counterpart particle is on the other side of the galaxy. This was abhorrent to Einstein, because it suggests information might be transmitted between the particles faster than light, breaking the universal speed limit set by his theory of special relativity. Instead, he and others posited, perhaps the entangled particles somehow shared “hidden variables” that are inaccessible to experiment but would determine the particles’ subsequent behavior when measured. In 1964 the physicist John Bell devised a way to test Einstein’s idea, calculating a limit that physicists could statistically measure for how much hidden variables could possibly correlate with the behavior of entangled particles. If experiments showed this limit to be exceeded, then Einstein’s idea of hidden variables would be incorrect.

    Ever since the 1970s “Bell tests” by physicists across ever-larger swaths of spacetime have shown that Einstein was indeed mistaken, and that entangled particles do in fact surpass Bell’s strict limits. The most definitive test arguably occurred in the Netherlands in 2015, when a team at Delft University of Technology closed several potential “loopholes” that had plagued past experiments and offered slim-but-significant opportunities for the influence of hidden variables to slip through. That test, though, involved separating entangled particles by scarcely more than a kilometer. With Micius’s transmission of entangled photons between widely separated ground stations, Pan’s team has now performed a Bell test at distances a thousand times greater. Just as before, their results confirm that Einstein was wrong. The quantum realm remains a spooky place—although no one yet understands why.

    “Of course, no one who accepts quantum mechanics could possibly doubt that entanglement can be created over that distance—or over any distance—but it’s still nice to see it made concrete,” says Scott Aaronson, a physicist at The University of Texas at Austin. “Nothing we knew suggested this goal was unachievable. The significance of this news is not that it was unexpected or that it overturns anything previously believed, but simply that it’s a satisfying culmination of years of hard work.”

    That work largely began in the 1990s when Pan, leader of the Chinese team, was a graduate student in the lab of the physicist Anton Zeilinger at the University of Innsbruck in Austria. Zeilinger was Pan’s PhD adviser, and they collaborated closely to test and further develop ideas for quantum communication. Pan returned to China to start his own lab in 2001, and Zeilinger started one as well at the Austrian Academy of Sciences in Vienna. For the next seven years they would compete fiercely to break records for transmitting entangled photon pairs across ever-wider gaps, and in ever-more extreme conditions, in ground-based experiments. All the while each man lobbied his respective nation’s space agency to green-light a satellite that could be used to test the technique from space. But Zeilinger’s proposals perished in a bureaucratic swamp at the European Space Agency whereas Pan’s were quickly embraced by the China National Space Administration. Ultimately, Zeilinger chose to collaborate again with his old pupil rather than compete against him; today the Austrian Academy of Sciences is a partner in QUESS, and the project has plans to use Micius to perform an intercontinental quantum key distribution experiment between ground stations in Vienna and Beijing.

    “I am happy that the Micius works so well,” Zeilinger says. “But one has to realize that it is a missed opportunity for Europe and others, too.”

    For years now, other researchers and institutions have been scrambling to catch up, pushing governments for more funding for further experiments on the ground and in space—and many of them see Micius’s success as the catalytic event they have been waiting for. “This is a major milestone, because if we are ever to have a quantum internet in the future, we will need to send entanglement over these sorts of long distances,” says Thomas Jennewein, a physicist at the University of Waterloo in Canada who was not involved with the study. “This research is groundbreaking for all of us in the community—everyone can point to it and say, ‘see, it does work!’”

    Jennewein and his collaborators are pursuing a space-based approach from the ground up, partnering with the Canadian Space Agency to plan a smaller, simpler satellite that could launch as soon as five years from now to act as a “universal receiver” and redistribute entangled photons beamed up from ground stations. At the National University of Singapore, an international collaboration led by the physicist Alexander Ling has already launched cheap shoe box–size CubeSats to create, study and perhaps even transmit photon pairs that are “correlated”—a situation just shy of full entanglement. And in the U.S., Kwiat at the University of Illinois is using NASA funding to develop a device that could someday test quantum communications using “hyperentanglement” (the simultaneous entanglement of photon pairs in multiple ways) onboard the International Space Station.

    Perhaps most significantly, a team led by Gerd Leuchs and Christoph Marquardt at the Max Planck Institute for the Science of Light in Germany is developing quantum communications protocols for commercially available laser systems already in space onboard the European Copernicus and SpaceDataHighway satellites. Using one of these systems, the team successfully encoded and sent simple quantum states to ground stations using photons beamed from a satellite in geostationary orbit, some 38,000 kilometers above Earth. This approach, Marquardt explains, does not rely on entanglement and is very different from that of QUESS—but it could, with minimal upgrades, nonetheless be used to distribute quantum keys for secure communications in as little as five years. Their results appear in Optica.

    “Our purpose is really to find a shortcut into making things like quantum key distribution with satellites economically viable and employable, pretty fast and soon,” Marquardt says. “[Engineers] invested 20 years of hard work making these systems, so it’s easier to upgrade them than to design everything from scratch. … It is a very good advantage if you can rely on something that is already qualified in space, because space qualification is very complicated. It usually takes five to 10 years just to develop that.”

    Marquardt and others suspect, however, that this field could be much further advanced than has been publicly acknowledged, with developments possibly hidden behind veils of official secrecy in the U.S. and elsewhere. It may be that the era of quantum communication is already upon us. “Some colleague of mine made the joke, ‘the silence of the U.S. is very loud,’” Marquardt says. “They had some very good groups concerning free-space satellites and quantum key distribution at Los Alamos [National Laboratory] and other places, and suddenly they stopped publishing. So we always say there are two reasons that they stopped publishing: either it didn’t work, or it worked really well!”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Scientific American, the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

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