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  • richardmitnick 8:53 am on May 5, 2016 Permalink | Reply
    Tags: Basic Research, , , FNAL G-2,   

    From Don Lincoln at FNAL: “The physics of g-2” 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    FNAL Don Lincoln
    Don Lincoln

    At any time in history, a few scientific measurements disagreed with the best theoretical predictions of the time. Currently, one such discrepancy involves the measurement of the strength of the magnetic field of a subatomic particle called a muon. In this video, Fermilab’s Dr. Don Lincoln explains this mystery and sketches ongoing efforts to determine if this disagreement signifies a discovery. If it does, this measurement will mean that we will have to rewrite the textbooks.


    Access the mp4 video here .

    Watch, enjoy, learn.

    FNAL G-2
    FNAL G-2

    FNAL Muon g-2 studio
    FNAL Muon g-2 studio

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 8:36 am on May 5, 2016 Permalink | Reply
    Tags: , An Active Black Hole in a Compact Dwarf, , Basic Research   

    From AAS NOVA: ” An Active Black Hole in a Compact Dwarf” 

    AASNOVA

    Amercan Astronomical Society

    4 May 2016
    Susanna Kohler

    1
    M32, circled in this photograph of the Andromeda galaxy and its satellites, is an example of a compact elliptical galaxy. These dwarfs are often found near massive galaxies (like Andromeda) — but a recent study has discovered an isolated, unusual compact elliptical. [Adapted from ESA/Hubble/R. Gendler]

    A new type of galaxy has just been added to the galaxy zoo: a small, compact, and old elliptical galaxy that shows signs of a monster black hole actively accreting material in its center. What can this unusual discovery tell us about how compact elliptical galaxies form?

    A New Galactic Beast

    Compact elliptical galaxies are an extremely rare early-type dwarf galaxy. Consistent with their name, compact ellipticals are small, very compact collections of ancient stars; these galaxies exhibit a high surface brightness and aren’t actively forming stars.

    2
    Optical view of the ancient compact elliptical galaxy SDSS J085431.18+173730.5 (center of image) in an SDSS color composite image. [Adapted from Paudel et al. 2016]

    SDSS Telescope at Apache Point, NM, USA
    SDSS Telescope at Apache Point, NM, USA

    Most compact ellipticals are found in dense environments, particularly around massive galaxies. This has led astronomers to believe that compact ellipticals might form via the tidal stripping of a once-large galaxy in interactions with another, massive galaxy. In this model, once the original galaxy’s outer layers are stripped away, the compact inner bulge component would be left behind as a compact elliptical galaxy. Recent discoveries of a few isolated compact ellipticals, however, have strained this model.

    Now a new galaxy has been found to confuse our classification schemes: the first-ever compact elliptical to also display signs of an active galactic nucleus. Led by Sanjaya Paudel (Korea Astronomy and Space Science Institute), a team of scientists discovered SDSS J085431.18+173730.5 serendipitously in Sloan Digital Sky Survey data. The team used SDSS images and spectroscopy in combination with data from the Canada-France-Hawaii Telescope to learn more about this unique galaxy.

    Puzzling Characteristics

    SDSS J085431.18+173730.5 presents an interesting conundrum. Ancient compact ellipticals are supposed to be devoid of gas, with no fuel left to trigger nuclear activity. Yet SDSS J085431.18+173730.5 clearly shows the emission lines that indicate active accretion onto a supermassive black hole of ~2 million solar masses, according to the authors’ estimates. Paudel and collaborators show that this mass is consistent with the low-mass extension of the known scaling relation between central black-hole mass and brightness of the host galaxy.

    3
    Central black hole mass vs. bulge K-band magnitude. SDSS J085431.18+173730.5 (red dot) falls right on the low-mass extension of the observed scaling relation. It has similar properties to M32, another compact elliptical galaxy. [Adapted from Paudel et al. 2016]

    To add to the mystery, SDSS J085431.18+173730.5 has no nearby neighbors: like the few other isolated compact ellipticals recently discovered, there are no massive galaxies in the immediate vicinity that could have led to its tidal stripping. So how was this puzzling ancient galaxy formed?

    The authors of this study* support a previously proposed “flyby” scenario: isolated compact ellipticals may simply be tidally stripped systems that ran away from their hosts. Paudel and collaborators suggest that SDSS J085431.18+173730.5 might have long ago interacted with NGC 2672 — a galaxy group located a whopping 6.5 million light-years away — before being flung out to its current location.

    Further studies of this unique galaxy’s emission profile, as well as efforts to learn about its underlying stellar population and central kinematics, will hopefully help us to better understand not only the origins of this galaxy, but how all compact ellipticals form and evolve.

    Citation

    Sanjaya Paudel et al 2016 ApJ 820 L19. doi:10.3847/2041-8205/820/1/L19

    Science paper:
    SDSS J085431.18+173730.5: THE FIRST COMPACT ELLIPTICAL GALAXY HOSTING AN ACTIVE NUCLEUS

    See the full article here .

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  • richardmitnick 8:07 am on May 5, 2016 Permalink | Reply
    Tags: , , Basic Research, Ultraluminous X-ray Sources   

    From astrobites: “Unveiling the Nature of Ultraluminous X-ray Sources” 

    Astrobites bloc

    Astrobites

    Science paper: Resolved Atomic Lines Reveal Outflows in Two Ultraluminous X-ray Sources (arXiv)
    Authors: Ciro Pinto, Matthew J. Middleton, and Andrew C. Fabian
    First Author’s Institution: Cambridge University
    Paper Status: Published in Nature

    As the name suggests, Ultraluminous X-ray Sources (ULXs) are objects that produce more X-rays than we would naively expect. To be “ultra” bright, their X-rays must shine brighter than a million Suns. If our own Sun shined this brightly, it would be tearing itself apart due to the massive amounts of radiation it would emit. ULXs are seriously bright.

    So what is a ULX? ULXs probably come a number of different objects, ranging from quasars to supernova remnants.

    Quasar. ESO/M. Kornmesser
    Quasar. ESO/M. Kornmesser

    Supernova remnant Crab nebula. NASA/ESA Hubble
    Supernova remnant Crab nebula. NASA/ESA Hubble

    The ULXs we’ll talk about today are variable on timescales as short as a few days. These volatile objects are most likely extreme X-ray binaries, or binary stars where one star is actually a compact object such as a neutron star or black hole.

    It’s actually really hard to figure out what the compact object might be! On the one hand, the compact object might be a neutron star with an extreme magnetic field whose pole faces us.

    Neutron star merger depicted Goddard
    Neutron star merger depicted Goddard

    This would cause the radiation from accretion to beam in our direction, making the object appear much brighter than it actually is. On the other hand, the compact object might actually be a black hole, in which case it would be need to be a rare “intermediate mass” black hole, with a mass hundreds to thousands of times larger than our own Sun, to explain the huge amount of energy coming from these objects.

    The authors of today’s paper try to tackle this mystery using astronomers’ favorite tool: high-resolution spectroscopy. Specifically, the authors take X-ray spectra, using the space telescopes XMM-Newton and Chandra, of two ULXs: one in the galaxy NGC 1313 (the cover art of this article) and the other in NGC 5408.

    ESA/XMM Newton
    ESA/XMM Newton

    NASA/Chandra Telescope

    Previous studies have used lower-resolution spectra and noticed that basic models couldn’t capture a lot of the apparent noise in the data. So it would make sense if this ‘noise’ was actually due to a plethora of unseen atomic lines littered across the spectra.

    1
    Fig 1: Part of the high resolution X-ray spectrum for the ULX in NGC 5408. The red/blue lines show different models for the data (black). Both absorption and emission features exist in the spectrum.

    And in fact there are! The authors find a forest of emission and absorption lines in the X-ray spectra (one of which is shown above), which means that the environments surrounding these similar ULXs are complex. They detect two notable features: First, adsorbed atomic lines which are blueshifted at 1/5th the speed of light. Recall that a blueshift means that the material is actually moving towards us, indicating that there is an extremely fast outflowing gas from the system! Second, they find atomic lines also in emission and neither redshifted nor blueshifted.

    So what does this mean? The authors claim that the blue-shifted absorption arises from an extremely fast outflow from the system as the material from the star accretes onto a black hole companion. This is commonly seen in other X-ray binaries with disks, but in this case the velocity is notably higher, implying higher energies. The emission lines are excited by a collisional battle between the accretion outflow and a wind from the donating star, leading to an even greater X-ray flux.

    Although this highly resolved look at this complex system offers a lot of insight into the physical picture, the authors can’t get a good constraint on the black hole’s mass from the dataset. They get a conservative upper limit of 40,000 times the mass of the Sun. For some perspective, a black hole this massive would actually only have a radius about twice the size of Jupiter.

    To reiterate, this work has highlighted how high resolution spectroscopy can resolve the atomic lines dominated the ‘noise’ in low-resolution spectra. This apparent ‘noise’ has been common among the ULXs stemming from X-ray binaries, suggesting a common origin for these radiant objects.

    See the full article here .

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    What do we do?

    Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
    Why read Astrobites?

    Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
    Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

     
  • richardmitnick 7:45 am on May 5, 2016 Permalink | Reply
    Tags: , Basic Research,   

    From ESA: “Models of Proba-3 designs” 

    WordPress is not fully functional at this point.

    ESA Space For Europe Banner

    European Space Agency

    04/05/2016
    G. Porter

    The design evolution of ESA’s Proba-3 double satellite is shown by this trio of 3D-printed models, each pair – from left to right – produced after successive development milestones.

    “These paired models, 3D printed in plastic, were not made for show,” explains Agnes Mestreau-Garreau, ESA’s project manager.

    “Instead, they’re used almost daily. Because Proba-3 will be the first precision formation-flying mission – with the two satellites flying in tandem– these models help the team to visualise their orientation, as well as to explain the mission easily to people. So the models have ended up somewhat battered as a result.

    “The first model set was printed after our System Requirements Review, followed by our Preliminary Design Review and now Mission Consolidation Milestone – with consequent changes in mission mass, volume and design details.“

    The latest member of ESA’s experimental Proba minisatellite family, Proba-3’s paired satellites will manoeuvre relative to each other with millimetre and fraction-of-a-degree precision, intended to serve as the virtual equivalent of a giant structure in space and so open up a whole new way of running space missions.

    As has become traditional with Proba missions, the success of Proba-3’s technology will be proven through acquiring high-quality scientific data. In this case, the smaller ‘occulter’ satellite will blot out the Sun’s fiery disc as viewed by the larger ‘coronagraph’ satellite, revealing mysterious regions of our parent star’s ghostly ‘corona’, or outer atmosphere.

    When in Sun-observing mode, the two satellites will maintain formation exactly 150 m apart, lined up with the Sun so the occulter casts a shadow across the face of the coronagraph, blocking out solar glare to come closer to the Sun’s fiery surface than ever before, other than during frustratingly brief terrestrial solar eclipses.

    The challenge is in keeping the satellites safely controlled and correctly positioned relative to each other. This will be accomplished using various new technologies, including bespoke formation-flying software, GPS information, intersatellite radio links, startrackers, and optical visual sensors and optical metrologies for close-up manoeuvring.

    Fifteen ESA Member States are participating in the Proba-3 consortium, with SENER in Spain as prime contractor for the satellite platforms and Centre Spatial de Liège in Belgium as prime contractor for the coronagraph.

    “This grouping includes several of the newer ESA Member States, including the Czech Republic, Poland and Romania,” adds Agnes.

    “It is a strength of this kind of small but ambitious mission that new entrants to the space sector can find important industrial roles to play on a more flexible basis than in some larger-scale programmes.”

    Proba-3’s next milestone will be the Payload Critical Design Review for its coronagraph, expected in the autumn followed by the System Critical Design Review for the mission. The two satellites will be stacked together for launch in 2019 before separating in orbit.

    See the full article here http://www.esa.int/spaceinimages/Images/2016/05/Models_of_Proba-3_designs.

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 7:33 am on May 5, 2016 Permalink | Reply
    Tags: , Basic Research, Keck   

    From Keck: “Even in Deep Space, There Are Shades of Black” 

    WordPress is not working properly. I will do the best that I can.

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    May 3, 2016
    BY FARISA Y. MORALES for Zocalo Public Square

    In my line of work, I stare at shades of black.

    My work starts on dark, black nights, when there is no moon or reflection from it. The telescopes I use have to be in places with three qualities: High, dry, and — you guessed it — very dark. And so, I search for planets atop the summit of the highest, driest, and darkest peak in Hawaii. Mauna Kea, a dormant volcano — where the world-famous W, M, Keck Observatory is located — minimizes the “noise” in the images from Earth’s constantly swirling atmosphere and the light drifting in from cities.

    Because black is defined by the absence of light, you might not think there are different gradations of black — but there are when you are hunting for other planets in our galaxy. Every day, I am looking through images that appear, at first, like exposures devoid of any light. In reality, shades of black can hide amazing worlds — some of which could be habitable or inhabited by life forms.

    Seeing the color black in fact is a comforting affirmation that I’m searching in the right direction, for a planet must be so faint as to appear to not be there at all. If an image has many bright dots of light, that means I am looking at a field full of stars. I am not interested in objects that emit their own light. A star is too extreme an environment for life as we know it — it’s an enormous ball of hot plasma and even if it had a solid surface to stand on, which it doesn’t, life forms like us would get crushed under the star’s tremendous gravitational pull.

    What I’m trying to find are very faint objects that reflect and re-emit the light from a host star nearby. These planets outside our solar system — which are known as exoplanets — are companions to stars, swimming in their own sea of darkness. Finding these planets tells us about the architecture of planetary systems. It also lets us know how common exoplanets are in the habitable regions around stars, where the temperatures are not too hot and not too cold, where liquid water can exist, and complex molecules may have figured out the processes we call life.


    Sample image of searching for a planet around a mature star, taken in March 2016 with the NIRC2 camera on Keck II telescope.

    My research uses the newest planet-hunting technique — “direct imaging.” Put simply, we place a small piece of black film in the field of view of the telescope to dampen the light from the parent star. Then, astronomers like myself can make out the faint planet companions orbiting the star. We rotate the powerful Keck telescope, taking pictures in a time-lapsed sequence, and then apply an intensive mathematical data analysis procedure. Through this process, we can carefully distinguish the feeble signal of a planet from the overwhelming glow of the host star. The dark piece of film is called a coronagraph, and it is a key component of the direct imaging technique.

    That’s right, I am actually trying to make the picture darker because the natural blackness of space is not enough to be able to see what we want to see. In order to extract the signal of a planet in an image, there is a lot of interference I have to take out: the random noise from the camera’s own electronics, the scattered light around the coronagraph, and the rotation of the individual exposures. The final image, a deeper tone of black, is the result of stacking cleaned-up exposures to reveal a clear signal from the planetary system. Galileo Galilei, the first observational astronomer, would be fascinated to see how we’ve progressed in the last 400 years. We are now seeing planets in the blackness around other stars, very much in the same way he discovered the faint moon companions around Jupiter.

    I did not set out to stare at blackness all day long. I came to astronomy by way of mathematics, which is a great tool for designing ways to see very small perturbations in data. But as I learned more about how astronomy could help expand the boundaries of human knowledge, I became more and more interested in trying to see what the universe conceals in the darkness.

    Ultimately, this is what all research is — seeking light in the darkness of the unknown. Our bodies are limited by the sensitivity of the human eye, but we have expanded our searches by manipulating the pixels of more sensitive cameras, and can thus capture evidence of real physical phenomena with our machines. If humans are to learn about how we came to be and search for life beyond ourselves, we must continue to look for answers in the deep blackness of space. And of course, we have to combine that with a little patience for staring into what may seem like a lot of nothingness.

    See the full article here. http://www.keckobservatory.org/recent/entry/even_in_deep_space_there_are_shades_of_black

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    Keck NASA

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  • richardmitnick 4:54 pm on May 3, 2016 Permalink | Reply
    Tags: Argentina, , Basic Research,   

    From ESA: “ESA extends global ties” 

    ESA Space For Europe Banner

    European Space Agency

    3 May 2016

    1
    Opening Malargüe, 19/12/2012

    As an intergovernmental space agency, ESA engages with countries well beyond those of its member states. A key partnership is with Argentina, one of South America’s most space-connected countries.

    Argentina was a founding member of the International Astronautical Federation, the world’s foremost space advocacy organisation, and, in the 1960s, established one of Latin America’s first space offices.

    By 1997, ESA and Argentina had begun their first formal cooperation, inking an agreement for Argentine use of data from the Agency’s ERS-1 and ERS-2 Earth observation missions. This ensured access to a vast repository of information about Earth’s land, water, ice and atmosphere until 2011.

    In 2002, a more general cooperation agreement was signed, currently in effect until 2023. Under this, ESA and Argentina’s CONAE space office have organised courses and grants for Argentine students as well as workshops in South America studying applications for Earth observation data, particularly in hydrology, natural disaster monitoring and radar applications.

    One of the most visible results came in 2012, with the inauguration of the Agency’s third deep-space ground tracking station, at Malargüe, about 1200 km west of Buenos Aires.

    As well as strong national support and the expertise of local industry, Argentina’s geography proved invaluable. ESA’s need was for a station at Argentine longitudes (and in the southern hemisphere) to complete around-the-globe tracking coverage together with ESA’s first and second deep-space stations in Australia and Spain.

    Malargüe station supports many of ESA’s most important exploration missions, including Rosetta, Mars Express, ExoMars, LISA Pathfinder and Gaia.

    ESA/Rosetta spacecraft
    ESA/Rosetta spacecraft

    ESA/Mars Express Orbiter
    ESA/Mars Express Orbiter

    ESA/LISA Pathfinder
    ESA/LISA Pathfinder

    ESA/Gaia satellite
    ESA/Gaia satellite

    Future ESA missions, such as Euclid, will push the development of the Malargüe station even further, requiring an evolution of the infrastructure to provide solid reliability with even higher-capacity data links.

    ESA/Euclid spacecraft
    ESA/Euclid spacecraft

    2
    ESA Malargüe tracking station

    As part of the arrangement with Argentina, 10% of the station’s time is available to Argentine scientists and engineers conducting research using the radio spectrum. This provides a unique opportunity to regional research teams.

    On 26 April 2016, two decades’ of cooperation between ESA and Argentina were spotlighted at a Jornada Espacial (Space Day) that marked the transfer of CONAE to the responsibility of a new minister at the Ministry of Science, Technology and Productive Innovation, and which saw senior ESA, CONAE and Argentine government officials reviewing past and current progress and looking at future projects.

    4
    Meeting the minister

    One of the most interesting developments discussed is a potential ESA mission dubbed Saocom-CS.

    ESA SAOCOM-CS
    ESA SAOCOM-CS

    Argentina’s two-satellite Saocom (Satélite Argentino de Observación COn Microondas) mission will study soil moisture and provide disaster monitoring, while ESA’s satellite would fly in formation with Saocom-1 for the study of boreal forests.

    Such data are of particular importance to Mendoza province, site of the Malargüe tracking station, where detailed knowledge of water use and conservation has a direct effect on the local economy – most notably its world-famous wine production.

    With almost 20 years’ of cooperation, and with the promise of deepening ties across missions related to Earth observation, education and training activities and deep-space science, ESA can look forward to strengthening its engagement with Argentina and the Latin American region.

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 2:32 pm on May 3, 2016 Permalink | Reply
    Tags: , Basic Research, ,   

    From SA: “Which Came First on Earth—Habitability or Life?” 

    Scientific American

    Scientific American

    May 3, 2016
    Shannon Hall

    One astronomer suggests that we cannot necessarily disentangle the two

    1
    These limestone cliffs along the English coastline are composed of calcium carbonate that formed when the skeletal remains of planktonic algae sank to the bottom of the ocean during the Cretaceous period. Credit: leo.wan/Flickr, CC BY 2.0

    The hunt for life on other planets is due for a makeover. Although it is often confined to planets orbiting in the so-called habitable zone where proximity to their host stars makes temperatures just right for liquid water, many astronomers are beginning to think outside the “Goldilocks” box. Some wonder if previously overlooked mechanisms—including life itself—could broaden the habitable zone well beyond its current definition. Colin Goldblatt, a planetary scientist at the University of Victoria in British Columbia, even argues that life’s ability to alter a planet’s climate poses a new paradox: A planet’s habitability could depend on whether life has already made itself at home there, a situation that would place habitability and life in a baffling chicken-or-egg scenario.

    Goldblatt has been looking beyond Earth-like atmospheres to see how different concentrations of nitrogen and carbon dioxide might tweak a planet’s habitability. Higher concentrations of carbon dioxide, for example, could keep a planet that is relatively far from its host star toasty whereas lower concentrations could keep a close-in planet chilly. Nitrogen is more complicated because higher concentrations both scatter sunlight (helping cool a planet) and make greenhouse gases absorb light more efficiently (keeping it warmer). At the fall 2015 American Geophysical Union meeting in San Francisco, Goldblatt argued these gases could help keep a planet habitable. He recently summarized his talk in a paper* published to the preprint server arXiv.

    NASA Orbiting Carbon Observatory 2, NASA JPL-Caltech
    NASA Orbiting Carbon Observatory 2, NASA JPL-Caltech

    “It’s a property of the planet that you’re living on.” Earth, for example, has a built-in temperature control system: the carbon–silicate cycle. Some 2.5 billion years ago the sun was so faint that the oceans should have been frozen—but they were not. The simple explanation is that Earth likely boasted an atmosphere thick with greenhouse gases. Then as the sun’s brightness grew, the planet counteracted the warming climate by scrubbing carbon dioxide from the air: Higher temperatures increased rainfall, which pulled the greenhouse gas from the atmosphere and carried it into the oceans, where plate tectonics eventually subducted it into Earth’s mantle. Today most of the world’s carbon dioxide is safely stored beneath Earth’s crust. Had the opposite occurred and the sun’s brightness waned, the planet might have counteracted the cooling climate by pumping more carbon dioxide into the air. Cooler temperatures would have slowed precipitation and increased volcanic eruptions, spewing the greenhouse gas out of the Earth’s mantle and back into the atmosphere.

    This balancing act has stabilized Earth’s climate for billions of years, letting the carbon dioxide swing up or down by more than 1,000 percent in order to keep the planet’s temperature steady and thereby increase the size of its habitable zone. And it is not just due to geochemistry; the carbon–silicate cycle depends on biology as well. Carbon dioxide is removed from the ocean when sea creatures convert it into the calcium carbonate they use to build their shells. After those creatures die they sink into the deep ocean where their shells are subducted into the mantle. For an example of this phenomenon, Goldblatt points to the White Cliffs of Dover. These limestone cliffs along the English coastline are composed of calcium carbonate that formed when the skeletal remains of planktonic algae sank to the bottom of the ocean during the Cretaceous period. It appears that levels of both carbon dioxide and nitrogen (which is similarly whipped between Earth’s mantle and atmosphere) can be subject to a planet’s biosphere. Life creates conditions that help sustain itself.

    “The existence of a biosphere actually increases the span of a habitable zone in a given solar system,” Crisp says. “The habitability of an environment is affected to a certain extent by whether or not it is inhabited by some life form.” Although this is generally agreed on, Goldblatt takes it a step further by saying that we cannot disentangle a habitable planet from the presence of life itself. “The thing that I want to push in this paper is a philosophical point—not a point of technical calculations,” Goldblatt says. “You can’t try to address whether a planet is suitable for life or not without considering whether there is already life on the planet.” Whereas most astronomers search for worlds that are suited to host life around other stars, Goldblatt does not think a planet can be called “habitable.” It is either inhabited, or it is not. If we find a lifeless Earth-like planet in the so-called habitable zone and we just plop an egg of life on that planet, there is no guarantee that life will take hold, Goldblatt says. “We have no idea what a planet at that [distance] without life would actually look like,” he says. “It would look nothing at all like the Earth.”

    Although this paradox might make the search for life look bleak, Goldblatt is hopeful we will find life in the galaxy. He simply thinks that astronomers should not confine themselves to such a strict definition of the habitable zone around stars. Life might exist within those bounds or it might exist well beyond them in ways that scientists have yet to imagine. To demonstrate his point he told me a story about Carl Sagan. When Cassini first arrived at Saturn, the spacecraft beamed images back to Earth where Sagan and other scientists could watch them first appear in a room at JPL. Most scientists attempted to interpret the results immediately, but Sagan remained quiet. He knew that the theoretical postulating was over. It was time to let the data speak for itself. “When we went out in the solar system we found things that we never expected,” Goldblatt says. “And when we go out to observe the atmospheres on planets, we’re going to find things that we don’t expect. We need to be ready to broaden our horizons.”

    *Science paper:
    The inhabitance paradox: how habitability and inhabitancy are inseparable

    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 1:52 pm on May 3, 2016 Permalink | Reply
    Tags: Basic Research, ,   

    From FNAL: “Preparing for the sterile neutrino search: Fermilab breaks ground on Short-Baseline Near Detector building” 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    May 3, 2016
    Rashmi Shivni

    1
    Fermilab broke ground on the Short-Baseline Neutrino Detector building on April 27. From left: Josh Kenney, FESS; Steve Dixon, AD; David Schmitz, University of Chicago; Ting Miao, ND; Ornella Palamara, ND; Peter Wilson, ND; Catherine James, ND. Photo: Reidar Hahn

    FNAL Short-Baseline Near Detector
    FNAL Short-Baseline Near Detector

    On April 27, Fermilab broke ground on the building that will house the future Short-Baseline Near Detector.

    The particle detector, SBND, is one of three that, together, scientists will use to search for the sterile neutrino, a hypothesized particle whose existence, if confirmed, could not only help us better understand the types of neutrino we already know about, but also provide clues about how the universe formed.

    Members of the Fermilab Neutrino and Particle Physics divisions, working together with international collaborators, are currently refining the design of the detector itself. It will take about eight months to complete the SBND building.

    The three detectors make up the laboratory’s Short-Baseline Neutrino Program, which will use a powerful neutrino beam generated by the Fermilab accelerator complex. The beam will pass first through SBND and then through the MicroBooNE detector, which is already installed and taking data, having observed its first neutrino interactions in October. Finally, the beam will travel through ICARUS, the largest of the three detectors. ICARUS, which was used in a previous experiment at the Italian Gran Sasso laboratory, is currently at the CERN laboratory in Switzerland receiving upgrades before its big move to Fermilab in 2017.

    FNAL/Microboone
    FNAL/MicrobooNE

    FNAL/ICARUS
    FNAL/ICARUS

    INFN Gran Sasso ICARUS
    INFN Gran Sasso ICARUS, previous home of ICARUS

    “The entire Short-Baseline Neutrino Program is looking for oscillations, or the transformations, of muon neutrinos into electron neutrinos,” said Peter Wilson, SBN program coordinator. “Sterile neutrinos might have a role in this oscillation process.”

    The beam coming out of the accelerator comprises primarily muon neutrinos; the detectors will measure their transformation into electron neutrinos.

    All three detectors have specific functions in detecting the transformation. As the detector closest to the beam source, SBND will take an initial measurement of the beam’s composition – how much the beam contains each of the different neutrino types.

    “The intermediary and far detectors are used to search for sterile neutrinos in two different ways,” said Ornella Palamara, co-spokesperson for the SBND experiment. “Either there’s an appearance of an excess of electron neutrinos or there’s a disappearance of the number of muon neutrinos compared to the number we start with.”

    If there are more electron neutrinos than predicted, then muon neutrinos may have oscillated first into sterile neutrinos and then to electron neutrinos. If the data show a smaller number of muon neutrinos than predicted, the muon neutrinos may have transformed only into sterile neutrinos, which cannot be seen in the far detectors.

    Scientists first picked up on experimental hints of a sterile neutrino at Los Alamos National Laboratory’s LSND experiment in 1995. When the Fermilab experiment MiniBooNE followed up, scientists could not confirm the sterile neutrino’s existence, but neither could they rule it out.

    “That’s the power of this program,” Palamara said. “We’re building off previous measurements, but we have more sensitive tools to measure the neutrinos.”

    Part of the sensitivity of SBND lies in its liquid-argon time projection chamber, the active part of the detector, which will contain 112 tons of liquid argon. Neutrinos will interact with the nuclei of the argon atoms, and scientists on SBND will study the resulting particles to better understand the neutrinos that caused the interaction. Their findings will likely have application in future accelerator-based neutrino programs, such as the international Deep Underground Neutrino Experiment hosted by Fermilab.

    The Short-Baseline Neutrino Program will begin taking data in 2018.

    “The SBND groundbreaking is a noteworthy milestone, but it’s part of a much larger program,” Wilson said. “Many people are working on it, and everyone is excited to get the chance to understand new physics.”

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 1:40 pm on May 3, 2016 Permalink | Reply
    Tags: , Basic Research, EXO-200 experiment, ,   

    From Symmetry: “EXO-200 resumes its underground quest” 

    Symmetry Mag
    Symmetry

    05/03/16
    Matthew R. Francis

    EXO-200 Enriched Xenon Observatory near Carlsbad, New Mexico
    SLAC EXO-200 Enriched Xenon Observatory near Carlsbad, New Mexico

    The upgraded experiment aims to discover if neutrinos are their own antiparticles.

    Science is often about serendipity: being open to new results, looking for the unexpected.

    The dark side of serendipity is sheer bad luck, which is what put the Enriched Xenon Observatory experiment, or EXO-200, on hiatus for almost two years.

    Accidents at the Department of Energy’s underground Waste Isolation Pilot Project (WIPP) facility near Carlsbad, New Mexico, kept researchers from continuing their search for signs of neutrinos and their antimatter pairs. Designed as storage for nuclear waste, the site had both a fire and a release of radiation in early 2014 in a distant part of the facility from where the experiment is housed. No one at the site was injured. Nonetheless, the accidents, and the subsequent efforts of repair and remediation, resulted in a nearly two-year suspension of the EXO-200 effort.

    Things are looking up now, though: Repairs to the affected area of the site are complete, new safety measures are in place, and scientists are back at work in their separate area of the site, where the experiment is once again collecting data. That’s good news, since EXO-200 is one of a handful of projects looking to answer a fundamental question in particle physics: Are neutrinos and antineutrinos the same thing?

    The neutrino that wasn’t there

    Each type of particle has its own nemesis: its antimatter partner. Electrons have positrons—which have the same mass but opposite electric charge—quarks have antiquarks and protons have antiprotons. When a particle meets its antimatter version, the result is often mutual annihilation. Neutrinos may also have antimatter counterparts, known as antineutrinos. However, unlike electrons and quarks, neutrinos are electrically neutral, so antineutrinos look a lot like neutrinos in many circumstances.

    In fact, one hypothesis is that they are one and the same. To test this, EXO-200 uses 110 kilograms of liquid xenon (of its 200kg total) as both a particle source and particle detector. The experiment hinges on a process called double beta decay, in which an isotope of xenon has two simultaneous decays, spitting out two electrons and two antineutrinos. (“Beta particle” is a nuclear physics term for electrons and positrons.)

    If neutrinos and antineutrinos are the same thing, sometimes the result will be neutrinoless double beta decay. In that case, the antineutrino from one decay is absorbed by the second decay, canceling out what would normally be another antineutrino emission. The challenge is to determine if neutrinos are there or not, without being able to detect them directly.

    “Neutrinoless double beta decay is kind of a nuclear physics trick to answer a particle physics problem,” says Michelle Dolinski, one of the spokespeople for EXO-200 and a physicist at Drexel University. It’s not an easy experiment to do.

    EXO-200 and similar experiments look for indirect signs of neutrinoless double beta decay. Most of the xenon atoms in EXO-200 are a special isotope containing 82 neutrons, four more than the most common version found in nature. The isotope decays by emitting two electrons, changing the atom from xenon into barium. Detectors in the EXO-200 experiment collect the electrons and measure the light produced when the beta particles are stopped in the xenon. These measurements together are what determine whether double beta decay happened, and whether the decay was likely to be neutrinoless.

    EXO-200 isn’t the only neutrinoless double beta decay experiment, but many of the others use solid detectors instead of liquid xenon. Dolinski got her start on the CUORE experiment, a large solid-state detector, but later changed directions in her research.

    CUORE experiment UC Berkeley
    CUORE experiment UC Berkeley

    “I joined EXO-200 as a postdoc in 2008 because I thought that the large liquid detectors were a more scalable solution,” she says. “If you want a more sensitive liquid-state experiment, you can build a bigger tank and fill it with more xenon.”

    Neutrinoless or not, double beta decay is very rare. A given xenon atom decays randomly, with an average lifetime of a quadrillion times the age of the universe. However, if you use a sufficient number of atoms, a few of them will decay while your experiment is running.

    “We need to sample enough nuclei so that you would detect these putative decays before the researcher retires,” says Martin Breidenbach, one of the EXO-200 project leaders and a physicist at the Department of Energy’s SLAC National Accelerator Laboratory.

    But the experiment is not just detecting neutrinoless events. Heavier neutrinos mean more frequent decays, so measuring the rate reveals the neutrino mass — something very hard to measure otherwise.

    Prior runs of EXO-200 and other experiments failed to see neutrinoless double beta decay, so either neutrinos and antineutrinos aren’t the same particle after all, or the neutrino mass is small enough to make decays too rare to be seen during the experiment’s lifetime. The current limit for the neutrino mass is less than 0.38 electronvolts—for comparison, electrons are about 500,000 electronvolts in mass.

    2
    SLAC National Accelerator Laboratory’s Jon Davis checks the enriched xenon storage bottles before the refilling of the TPC. Brian Dozier, Los Alamos National Laboratory

    Working in the salt mines

    Cindy Lin is a Drexel University graduate student who spends part of her time working on the EXO-200 detector at the mine. Getting to work is fairly involved.

    “In the morning we take the cage elevator half a mile down to the mine,” she says. Additionally, she and the other workers at WIPP have to take a 40-hour safety training to ensure their wellbeing, and wear protective gear in addition to normal lab clothes.

    “As part of the effort to minimize salt dust particles in our cleanroom, EXO-200 scientists also cover our hair and wear coveralls,” Lin adds.

    The sheer amount of earth over the detector shields it from electrons and other charged particles from space, which would make it too hard to spot the signal from double beta decay. WIPP is carved out of a sodium chloride deposit—the same stuff as table salt—that has very little uranium or the other radioactive minerals you find in solid rock caverns. But it has its drawbacks, too.

    “Salt is very dynamic: It moves at the level of centimeters a year, so you can’t build a nice concrete structure,” says Breidenbach. To compensate, the EXO-200 team has opted for a more modular design.

    The inadvertent shutdown provided extra challenges. EXO-200, like most experiments, isn’t well suited for being neglected for more than a few days at a time. However, Lin and other researchers worked hard to get the equipment running for new data this year, and the downtime also allowed researchers to install some upgraded equipment.

    The next phase of the experiment, nEXO, is at a conceptual stage based on what has been learned from EXO200. Experimenters are considering the benefits of moving the project deeper underground, perhaps at a facility like the Sudbury Neutrino Observatory (SNOlab) in Canada.
    SNOLAB, Sudbury, Ontario, Canada.
    SNOLAB
    SNOLAB, Sudbury, Ontario, Canada

    Dolinski is optimistic that if there are any neutrinoless double beta decays to see, nEXO or similar experiments should see them in the next 15 years or so.

    Then, maybe we’ll know if neutrinos and antineutrinos are the same and find out more about these weird low-mass particles.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:18 pm on May 3, 2016 Permalink | Reply
    Tags: , Basic Research, ,   

    From CfA: “Planet Nine: A World That Shouldn’t Exist” 

    Smithsonian Astrophysical Observatory
    Smithsonian Astrophysical Observatory

    [This subject is getting old, but this article presents three new papers on the subject.]

    May 3, 2016
    Christine Pulliam
    Media Relations Manager
    Harvard-Smithsonian Center for Astrophysics
    617-495-7463

    1
    Alleged Planet nine. No image credit.

    Planet nine orbit image Credit Caltech R. Hurt (IPAC)
    Planet nine orbit image Credit Caltech R. Hurt (IPAC)

    Earlier this year scientists presented evidence for Planet Nine, a Neptune-mass planet in an elliptical orbit 10 times farther from our Sun than Pluto. Since then theorists have puzzled over how this planet could end up in such a distant orbit.

    New research by astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) examines a number of scenarios and finds that most of them have low probabilities. Therefore, the presence of Planet Nine remains a bit of a mystery.

    “The evidence points to Planet Nine existing, but we can’t explain for certain how it was produced,” says CfA astronomer Gongjie Li, lead author on a paper accepted for publication* in the Astrophysical Journal Letters.

    Planet Nine circles our Sun at a distance of about 40 billion to 140 billion miles, or 400 – 1500 astronomical units. (An astronomical unit or A.U. is the average distance of the Earth from the Sun, or 93 million miles.) This places it far beyond all the other planets in our solar system. The question becomes: did it form there, or did it form elsewhere and land in its unusual orbit later?

    Li and her co-author Fred Adams (University of Michigan) conducted millions of computer simulations in order to consider three possibilities. The first and most likely involves a passing star that tugs Planet Nine outward. Such an interaction would not only nudge the planet into a wider orbit but also make that orbit more elliptical. And since the Sun formed in a star cluster with several thousand neighbors, such stellar encounters were more common in the early history of our solar system.

    However, an interloping star is more likely to pull Planet Nine away completely and eject it from the solar system. Li and Adams find only a 10 percent probability, at best, of Planet Nine landing in its current orbit. Moreover, the planet would have had to start at an improbably large distance to begin with.

    CfA astronomer Scott Kenyon believes he may have the solution to that difficulty. In two papers submitted to the Astrophysical Journal, Kenyon and his co-author Benjamin Bromley (University of Utah) use computer simulations to construct plausible scenarios for the formation of Planet Nine in a wide orbit.

    “The simplest solution is for the solar system to make an extra gas giant,” says Kenyon.

    They propose that Planet Nine formed much closer to the Sun and then interacted with the other gas giants, particularly Jupiter and Saturn. A series of gravitational kicks then could have boosted the planet into a larger and more elliptical orbit over time.

    “Think of it like pushing a kid on a swing. If you give them a shove at the right time, over and over, they’ll go higher and higher,” explains Kenyon. “Then the challenge becomes not shoving the planet so much that you eject it from the solar system.”

    That could be avoided by interactions with the solar system’s gaseous disk, he suggests.

    Kenyon and Bromley also examine the possibility that Planet Nine actually formed at a great distance to begin with. They find that the right combination of initial disk mass and disk lifetime could potentially create Planet Nine in time for it to be nudged by Li’s passing star.

    “The nice thing about these scenarios is that they’re observationally testable,” Kenyon points out. “A scattered gas giant will look like a cold Neptune, while a planet that formed in place will resemble a giant Pluto with no gas.”

    Li’s work also helps constrain the timing for Planet Nine’s formation or migration. The Sun was born in a cluster where encounters with other stars were more frequent. Planet Nine’s wide orbit would leave it vulnerable to ejection during such encounters. Therefore, Planet Nine is likely to be a latecomer that arrived in its current orbit after the Sun left its birth cluster.

    Finally, Li and Adams looked at two wilder possibilities: that Planet Nine is an exoplanet that was captured from a passing star system, or a free-floating planet that was captured when it drifted close by our solar system. However, they conclude that the chances of either scenario are less than 2 percent.

    Li and Adams’ paper has been accepted for publication in the Astrophysical Journal Letters and is available online*. Kenyon and Bromley have submitted their findings to the Astrophysical Journal in two papers available online: one on in-situ formation** and one on gas-giant scattering***.

    *Science paper:
    Interaction Cross Sections and Survival Rates for Proposed Solar System Member Planet Nine

    **Science Paper:
    Making Planet Nine: Pebble Accretion at 250–750 AU in a Gravitationally Unstable Ring

    ***Science paper:
    Making Planet Nine: A Scattered Giant in the Outer Solar System

    See the full article here .

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    About CfA

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy. The long relationship between the two organizations, which began when the SAO moved its headquarters to Cambridge in 1955, was formalized by the establishment of a joint center in 1973. The CfA’s history of accomplishments in astronomy and astrophysics is reflected in a wide range of awards and prizes received by individual CfA scientists.

    Today, some 300 Smithsonian and Harvard scientists cooperate in broad programs of astrophysical research supported by Federal appropriations and University funds as well as contracts and grants from government agencies. These scientific investigations, touching on almost all major topics in astronomy, are organized into the following divisions, scientific departments and service groups.

     
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