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  • richardmitnick 5:14 pm on May 24, 2016 Permalink | Reply
    Tags: , , , Puffy Giant Planet Discovered by KELT-S Transit Survey   

    From NOAO: “Puffy Giant Planet Discovered by KELT-S Transit Survey” 

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    The discovery lightcurve of exoplanet KELT-10b is overlaid on an image of the KELT-S Telescope in South Africa. The lightcurve was obtained using 4967 observations over about 4-years. A 30-minute binned lightcurve is shown in red. Image Credit: R. Kuhn & Vanderbilt University/SAAO.

    Transiting planets orbiting bright stars provide a golden opportunity to learn about the nature of exoplanets, their composition and origin. A robotic survey of the southern sky, designed to detect such systems, has discovered its first exoplanet: KELT-10b, a highly inflated giant planet. Although it is only 2/3 the mass of Jupiter, KELT-10b is 40% larger than Jupiter in radius. Because of its large size, when the planet passes in front of its star, it blocks out a whopping 1.4% of the star’s light, generating a transit signal that is relatively easy to detect. As one of only 25 planets known to transit bright stars (V < 11) in the southern hemisphere, KELT-10b is an attractive target for future studies aimed at characterizing planetary atmospheres.

    KELT-10b was discovered by the Kilodegree Extremely LIttle Telescope-South (KELT-S) transit survey. KELT-S is a robotic telescope located at the Sutherland site of the South African Astronomical Observatory. It is operated by Vanderbilt University and the South African Astronomical Observatory. NOAO astronomer David James is a founding member of the project.

    KELT South robotic telescope, Southerland, South Africa

    Describing his enthusiasm for the KELT-S project, James explained, “Efforts to detect and characterize extra-solar planets are driven by the deep-rooted desires of humanity to understand the origin of the solar system and their place in it. Although small aperture planet-hunting telescopes like KELT-S are typically are modest in budget, they deliver a strong return in science. They are also a powerful educational experience for students.”

    James is excited by the future of exoplanet research, as it moves from the era of exoplanet detection and taxonomy to the characterization of their atmospheres and searches for bio-signatures. He mused, “When my daughter is my age, perhaps having detected exoplanets of her own, she may well be using a 30-50m class telescope to describe their biology and potential for hosting life.”

    Science paper:
    KELT-10b: The First Transiting Exoplanet from the KELT-South Survey – A Hot Sub-Jupiter Transiting a V=10.7 Early G-Star

    See the full article here .

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    NOAO News
    NOAO is the US national research & development center for ground-based night time astronomy. In particular, NOAO is enabling the development of the US optical-infrared (O/IR) System, an alliance of public and private observatories allied for excellence in scientific research, education and public outreach.

    Our core mission is to provide public access to qualified professional researchers via peer-review to forefront scientific capabilities on telescopes operated by NOAO as well as other telescopes throughout the O/IR System. Today, these telescopes range in aperture size from 2-m to 10-m. NOAO is participating in the development of telescopes with aperture sizes of 20-m and larger as well as a unique 8-m telescope that will make a 10-year movie of the Southern sky.

    In support of this mission, NOAO is engaged in programs to develop the next generation of telescopes, instruments, and software tools necessary to enable exploration and investigation through the observable Universe, from planets orbiting other stars to the most distant galaxies in the Universe.

    To communicate the excitement of such world-class scientific research and technology development, NOAO has developed a nationally recognized Education and Public Outreach program. The main goals of the NOAO EPO program are to inspire young people to become explorers in science and research-based technology, and to reach out to groups and individuals who have been historically under-represented in the physics and astronomy science enterprise.

    The National Optical Astronomy Observatory is proud to be a US National Node in the International Year of Astronomy, 2009.

    About Our Observatories:
    Kitt Peak National Observatory (KPNO)

    Kitt Peak

    Kitt Peak National Observatory (KPNO) has its headquarters in Tucson and operates the Mayall 4-meter, the 3.5-meter WIYN , the 2.1-meter and Coudé Feed, and the 0.9-meter telescopes on Kitt Peak Mountain, about 55 miles southwest of the city.

    Cerro Tololo Inter-American Observatory (CTIO)

    NOAO Cerro Tolo

    The Cerro Tololo Inter-American Observatory (CTIO) is located in northern Chile. CTIO operates the 4-meter, 1.5-meter, 0.9-meter, and Curtis Schmidt telescopes at this site.

    The NOAO System Science Center (NSSC)

    Gemini North
    Gemini North

    Gemini South telescope
    Gemini South

    The NOAO System Science Center (NSSC) at NOAO is the gateway for the U.S. astronomical community to the International Gemini Project: twin 8.1 meter telescopes in Hawaii and Chile that provide unprecendented coverage (northern and southern skies) and details of our universe.

    NOAO is managed by the Association of Universities for Research in Astronomy under a Cooperative Agreement with the National Science Foundation.

     
  • richardmitnick 4:54 pm on May 24, 2016 Permalink | Reply
    Tags: , , , , ,   

    From Goddard: “NASA Scientist Suggests Possible Link Between Primordial Black Holes and Dark Matter” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    May 24, 2016
    Francis Reddy
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland

    Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe’s existence, known as primordial black holes. Now a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

    “This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good,” said Alexander Kashlinsky, an astrophysicist at NASA Goddard. “If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun’s mass.”

    In 2005, Kashlinsky led a team of astronomers using NASA’s Spitzer Space Telescope to explore the background glow of infrared light in one part of the sky.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    The researchers reported excessive patchiness in the glow and concluded it was likely caused by the aggregate light of the first sources to illuminate the universe more than 13 billion years ago. Follow-up studies confirmed that this cosmic infrared background (CIB) showed similar unexpected structure in other parts of the sky.

    Cosmic Infrared Background, Credit: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA)
    Cosmic Infrared Background, Credit: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA)

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    After masking out all known stars, galaxies and artifacts and enhancing what’s left, an irregular background glow appears. This is the cosmic infrared background (CIB); lighter colors indicate brighter areas.

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    This image from NASA’s Spitzer Space Telescope shows an infrared view of a sky area in the constellation Ursa Major.

    The CIB glow is more irregular than can be explained by distant unresolved galaxies, and this excess structure is thought to be light emitted when the universe was less than a billion years old. Scientists say it likely originated from the first luminous objects to form in the universe, which includes both the first stars and black holes.

    In 2013, another study compared how the cosmic X-ray background (CXB) detected by NASA’s Chandra X-ray Observatory compared to the CIB in the same area of the sky.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    The first stars emitted mainly optical and ultraviolet light, which today is stretched into the infrared by the expansion of space, so they should not contribute significantly to the CXB.

    Yet the irregular glow of low-energy X-rays in the CXB matched the patchiness of the CIB quite well. The only object we know of that can be sufficiently luminous across this wide an energy range is a black hole. The research team concluded that primordial black holes must have been abundant among the earliest stars, making up at least about one out of every five of the sources contributing to the CIB.

    The nature of dark matter remains one of the most important unresolved issues in astrophysics. Scientists currently favor theoretical models that explain dark matter as an exotic massive particle, but so far searches have failed to turn up evidence these hypothetical particles actually exist. NASA is currently investigating this issue as part of its Alpha Magnetic Spectrometer and Fermi Gamma-ray Space Telescope missions.

    AMS-02 Bloc
    NASA/AMS02 device
    AMS02

    NASA/Fermi Telescope
    NASA/Fermi Telescope

    “These studies are providing increasingly sensitive results, slowly shrinking the box of parameters where dark matter particles can hide,” Kashlinsky said. “The failure to find them has led to renewed interest in studying how well primordial black holes — black holes formed in the universe’s first fraction of a second — could work as dark matter.”

    Physicists have outlined* several ways in which the hot, rapidly expanding universe could produce primordial black holes in the first thousandths of a second after the Big Bang. The older the universe is when these mechanisms take hold, the larger the black holes can be. And because the window for creating them lasts only a tiny fraction of the first second, scientists expect primordial black holes would exhibit a narrow range of masses.

    On Sept. 14, gravitational waves produced by a pair of merging black holes 1.3 billion light-years away were captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Hanford, Washington, and Livingston, Louisiana.

    Caltech/MIT  Advanced Ligo Hanford, WA, USA installation
    Caltech/MIT Advanced Ligo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector in Livingston, Louisiana
    Caltech/MIT Advanced aLigo detector in Livingston, LA, USA

    This event marked the first-ever detection of gravitational waves as well as the first direct detection of black holes.


    Primordial black holes, if they exist, could be similar to the merging black holes detected by the LIGO team in 2014. This computer simulation shows in slow motion what this merger would have looked like up close. The ring around the black holes, called an Einstein ring, arises from all the stars in a small region directly behind the holes whose light is distorted by gravitational lensing. The gravitational waves detected by LIGO are not shown in this video, although their effects can be seen in the Einstein ring. Gravitational waves traveling out behind the black holes disturb stellar images comprising the Einstein ring, causing them to slosh around in the ring even long after the merger is complete. Gravitational waves traveling in other directions cause weaker, shorter-lived sloshing everywhere outside the Einstein ring. If played back in real time, the movie would last about a third of a second.
    Credits: SXS Lensing
    Access mp4 video here .

    The signal provided LIGO scientists with information about the masses of the individual black holes, which were 29 and 36 times the sun’s mass, plus or minus about four solar masses. These values were both unexpectedly large and surprisingly similar.

    In his new paper**, published May 24 in The Astrophysical Journal Letters, Kashlinsky analyzes what might have happened if dark matter consisted of a population of black holes similar to those detected by LIGO. The black holes distort the distribution of mass in the early universe, adding a small fluctuation that has consequences hundreds of millions of years later, when the first stars begin to form.

    For much of the universe’s first 500 million years, normal matter remained too hot to coalesce into the first stars. Dark matter was unaffected by the high temperature because, whatever its nature, it primarily interacts through gravity. Aggregating by mutual attraction, dark matter first collapsed into clumps called minihaloes, which provided a gravitational seed enabling normal matter to accumulate. Hot gas collapsed toward the minihaloes, resulting in pockets of gas dense enough to further collapse on their own into the first stars. Kashlinsky shows that if black holes play the part of dark matter, this process occurs more rapidly and easily produces the lumpiness of the CIB detected in Spitzer data even if only a small fraction of minihaloes manage to produce stars.

    As cosmic gas fell into the minihaloes, their constituent black holes would naturally capture some of it too. Matter falling toward a black hole heats up and ultimately produces X-rays. Together, infrared light from the first stars and X-rays from gas falling into dark matter black holes can account for the observed agreement between the patchiness of the CIB and the CXB.

    Occasionally, some primordial black holes will pass close enough to be gravitationally captured into binary systems. The black holes in each of these binaries will, over eons, emit gravitational radiation, lose orbital energy and spiral inward, ultimately merging into a larger black hole like the event LIGO observed.

    “Future LIGO observing runs will tell us much more about the universe’s population of black holes, and it won’t be long before we’ll know if the scenario I outline is either supported or ruled out,” Kashlinsky said.

    Kashlinsky leads science team centered at Goddard that is participating in the European Space Agency’s Euclid mission, which is currently scheduled to launch in 2020.

    ESA/Euclid spacecraft
    ESA/Euclid spacecraft

    The project, named LIBRAE, will enable the observatory to probe source populations in the CIB with high precision and determine what portion was produced by black holes.

    *Science paper:
    Primordial Black Holes – Recent Developments

    **Science paper:
    LIGO GRAVITATIONAL WAVE DETECTION, PRIMORDIAL BLACK HOLES, AND THE NEAR-IR COSMIC INFRARED BACKGROUND ANISOTROPIES

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 4:19 pm on May 24, 2016 Permalink | Reply
    Tags: , , Maria Zuber, ,   

    From MIT: “Maria Zuber elected as chair of the National Science Board” Women in Science 

    MIT News
    MIT News
    MIT Widget

    May 24, 2016
    The following is adapted from a National Science Foundation press release.

    For the first time in the history of the National Science Foundation (NSF), women now hold three key leadership positions — director of the NSF, and chair and vice-chair of its governing body, the National Science Board (NSB). During its May meeting, the NSB elected Maria Zuber, vice president for research at MIT, as its board chair, and Diane Souvaine, vice provost for research at Tufts University, as its vice chair. Zuber and Souvaine replace Dan Arvizu and Kelvin Droegemeier, who stepped down from the Board after twelve years of service, the last four as chair and vice chair.

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    Maria Zuber

    Zuber’s research bridges planetary geophysics and the technology of space-based laser and radio systems, and she has published over 200 papers. She has held leadership roles associated with scientific experiments or instrumentation on nine NASA missions and remains involved with six of these missions. The E.A. Griswold Professor of Geophysics at MIT, Zuber is a member of the National Academy of Sciences and the American Philosophical Society, and is a fellow of the American Academy of Arts and Sciences, the American Association for the Advancement of Science, the Geological Society of America, and the American Geophysical Union. In 2002, Discover magazine named her one of the 50 most important women in science. Zuber served on the Presidential Commission on the Implementation of United States Space Exploration Policy in 2004.

    Jointly, the 24-member NSB and the NSF director pursue the goals and function of the Foundation. The NSB establishes the policies of NSF within the framework of applicable national policies set forth by the president and Congress. The board also identifies issues that are critical to NSF’s future, approves the agency’s strategic budget directions and the annual budget submission to the Office of Management and Budget, and new major programs and awards. The NSB serves as an independent body of advisors to both the president and Congress on policy matters related to science and engineering and education in science and engineering. In addition to publishing major reports, the NSB publishes policy papers and statements on issues of importance to U.S. science and engineering.

    NSF director and NSB member ex officio France Córdova said, “I am delighted to say, on behalf of NSF, that we are thrilled with Dr. Zuber’s election as chair of the National Science Board. As a superb scientist and recognized university leader, she has the skills needed to help guide the agency’s policies and programs. I look forward to working with her as NSF launches new big ideas in science and engineering.”

    Zuber is in her fourth year on the NSB and has served on its Committee on Strategy and Budget.

    “It is a privilege to lead the National Science Board and to promote NSF’s bold vision for research and education in science and engineering,” said Zuber. “The outcomes of discovery science inspire the next generation and yield the knowledge that drives innovation and national competitiveness, and contribute to our quality of life. NSB is committed to working with Director Córdova and her talented staff to assure that the very best ideas based on merit review are supported and that exciting, emerging opportunities — many at the intersection of disciplines — are pursued.”

    Souvaine is in her second term on the NSB and has served as chair of its Committee on Strategy and Budget, chair of its Committee on Programs and Plans, and a member of its Committee on Audit and Oversight. In addition, she co-chaired the NSB’s Task Force on Mid-Scale Research and served three years on the Executive Committee.

    A theoretical computer scientist, Souvaine’s research in computational geometry has commercial applications in materials engineering, microchip design, robotics, and computer graphics. She was elected a fellow of the Association for Computing Machinery for her research and for her service on behalf of the computing community. A founding member, Souvaine served for over two years with the NSF Science and Technology Center on Discrete Mathematics and Theoretical Computer Science, that originally spanned Princeton University, Rutgers University, Bell Labs, and Bell Communications Research. She also works to enhance precollege mathematics and foundations of computing education and to advance opportunities for women and minorities in mathematics, science, and engineering.

    “I am truly honored and humbled by this vote of confidence from such esteemed colleagues. I do not take this responsibility lightly,” said Souvaine. “The board is proud of NSF’s accomplishments over its 66 years, from the discovery of gravitational waves at LIGO to our biennial Science and Engineering Indicators report on the state of our nation’s science and engineering enterprise. I look forward to working with Congress, the administration, the science and education communities, and NSF staff to continue the agency’s legacy in advancing the progress of science.”

    The president appoints NSB members, selected for their eminence in research, education, or public service and records of distinguished service, and who represent a variety of science and engineering disciplines and geographic areas. Board members serve six-year terms, and the president may reappoint members for a second term. NSF’s director is an ex officio 25th member of the board.

    See the full article here .

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

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  • richardmitnick 4:09 pm on May 24, 2016 Permalink | Reply
    Tags: Angela Gonzales, , ,   

    From Symmetry: “Of bison and bosons” Women in Science 

    Symmetry Mag

    Symmetry

    05/24/16
    Lauren Biron

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    Artwork by Angela Gonzales

    When talking about Fermilab’s distinct visual and artistic aesthetic, it’s impossible not to mention Angela Gonzales.

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    Angela Gonzales

    The artist – Fermilab’s 11th employee – joined the lab in 1967 and immediately began connecting the lab’s cutting-edge science with an artistic flair to match. She picked a color palette of bold blues and oranges and reds that would go on to adorn the campus’ buildings, and illustrated hundreds of posters, signs and report covers for the lab.

    She also designed the iconic logo and a beautiful graphic that has become an unofficial seal for the laboratory, most commonly found on the back of T-shirts. But what do all of the symbols mean?

    If all this symbolism isn’t enough for you—or if you’re a part of the coloring book craze and want to shade in a science drawing—fear not. Gonzales made an expanded version of this graphic. The buildings (clockwise from the top left) are the Meson Lab (now the Fermilab Test Beam Facility), the Geodesic Dome (now part of the Silicon Detector Facility), the CDF building (now part of the Illinois Accelerator Research Center) and the Pagoda (a small building that hosted a control room). She also incorporated four of the outdoor sculptures on the Fermilab site (clockwise from top): Tractricious, the Mobius Strip, Acqua Alle Funi and Broken Symmetry. You’ll also find some of the particle symbols from the core graphic, along with the symbols for π mesons, K mesons and gluons (g).

    [This beautiful work will become a part of my FNAL blog template.]

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 3:46 pm on May 24, 2016 Permalink | Reply
    Tags: , , , New Horizons Collects First Science on a Post-Pluto Object   

    From New Horizons: “New Horizons Collects First Science on a Post-Pluto Object” 

    NASA image

    NASA

    NASA/New Horizons spacecraft

    New Horizons

    May 17, 2016
    Tricia Talbert

    Warming up for a possible extended mission as it speeds through deep space, NASA’s New Horizons spacecraft has now twice observed 1994 JR1, a 90-mile-wide (145-kilometer-wide) Kuiper Belt object (KBO) orbiting more than 3 billion miles (5 billion kilometers) from the sun.

    Kuiper Belt. Minor Planet Center
    “Kuiper Belt. Minor Planet Center

    Science team members have used these observations to reveal new facts about this distant remnant of the early solar system.

    Taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI) on April 7-8 from a distance of about 69 million miles (111 million kilometers), the images shatter New Horizons’ own record for the closest-ever views of this KBO in November 2015, when New Horizons detected JR1 from 170 million miles (280 million kilometers) away.

    NASA New Horizons LORRI Camera
    NASA New Horizons LORRI Camera

    Simon Porter, a New Horizons science team member from Southwest Research Institute (SwRI) in Boulder, Colorado, said the observations contain several valuable findings. “Combining the November 2015 and April 2016 observations allows us to pinpoint the location of JR1 to within 1,000 kilometers (about 600 miles), far better than any small KBO,” he said, adding that the more accurate orbit also allows the science team to dispel a theory, suggested several years ago, that JR1 is a quasi-satellite of Pluto.

    From the closer vantage point of the April 2016 observations, the team also determined the object’s rotation period, observing the changes in light reflected from JR1’s surface to determine that it rotates once every 5.4 hours (or a JR1 day). “That’s relatively fast for a KBO,” said science team member John Spencer, also from SwRI. “This is all part of the excitement of exploring new places and seeing things never seen before.”

    Spencer added that these observations are great practice for possible close-up looks at about 20 more ancient Kuiper Belt objects that may come in the next few years, should NASA approve an extended mission. New Horizons flew through the Pluto system on July 14, 2015, making the first close-up observations of Pluto and its family of five moons. The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, 2014 MU69, on Jan. 1, 2019.

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    Above, the first two of the 20 observations that New Horizons made of 1994 JR1 in April 2016. The Kuiper Belt object is the bright moving dot indicated by the arrow. The dots that do not move are background stars. The moving features in the top left and far right are internal camera reflections (a kind of selfie) caused by illumination by a very bright star just outside of LORRI’s field of view; the one on the left shows the three arms that hold up LORRI’s secondary mirror. Credits: NASA/JHUAPL/SwRI

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    New Horizons scientists used light curve data – the variations in the brightness of light reflected from the object’s surface – to determine JR1’s rotation period of 5.4 hours.
    Credits: NASA/JHUAPL/SwRI

    See the full article here .

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    The New Horizons mission is helping us understand worlds at the edge of our solar system by making the first reconnaissance of the dwarf planet Pluto and by venturing deeper into the distant, mysterious Kuiper Belt – a relic of solar system formation.

    The Journey

    New Horizons launched on Jan. 19, 2006; it swung past Jupiter for a gravity boost and scientific studies in February 2007, and conducted a six-month-long reconnaissance flyby study of Pluto and its moons in summer 2015, culminating with Pluto closest approach on July 14, 2015. As part of an extended mission, pending NASA approval, the spacecraft is expected to head farther into the Kuiper Belt to examine another of the ancient, icy mini-worlds in that vast region, at least a billion miles beyond Neptune’s orbit.

    Sending a spacecraft on this long journey is helping us to answer basic questions about the surface properties, geology, interior makeup and atmospheres on these bodies.

    New Science

    The National Academy of Sciences has ranked the exploration of the Kuiper Belt – including Pluto – of the highest priority for solar system exploration. Generally, New Horizons seeks to understand where Pluto and its moons “fit in” with the other objects in the solar system, such as the inner rocky planets (Earth, Mars, Venus and Mercury) and the outer gas giants (Jupiter, Saturn, Uranus and Neptune).

    Pluto and its largest moon, Charon, belong to a third category known as “ice dwarfs.” They have solid surfaces but, unlike the terrestrial planets, a significant portion of their mass is icy material.

    Using Hubble Space Telescope images, New Horizons team members have discovered four previously unknown moons of Pluto: Nix, Hydra, Styx and Kerberos.

    A close-up look at these worlds from a spacecraft promises to tell an incredible story about the origins and outskirts of our solar system. New Horizons is exploring – for the first time – how ice dwarf planets like Pluto and Kuiper Belt bodies have evolved over time.

    The Need to Explore

    The United States has been the first nation to reach every planet from Mercury to Neptune with a space probe. New Horizons is allowing the U.S. to complete the initial reconnaissance of the solar system.

    A Team Approach

    The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate.

    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

     
  • richardmitnick 3:06 pm on May 24, 2016 Permalink | Reply
    Tags: , , , ,   

    From Hubble: “Hubble finds clues to the birth of supermassive black holes” 

    NASA Hubble Banner

    NASA Hubble Telescope

    Hubble

    24 May 2016
    At ESA/Hubble
    Fabio Pacucci
    Scuola Normale Superiore
    Pisa, Italy
    Email: fabio.pacucci@sns.it

    Andrea Ferrara
    Scuola Normale Superiore
    Pisa, Italy
    Email: andrea.ferrara@sns.it

    Andrea Grazian
    National Institute for Astrophysics
    Rome, Italy
    Email: grazian@oa-roma.inaf.it

    Mathias Jäger
    ESA/Hubble, Public Information Officer
    Garching bei München, Germany
    Tel: +49 176 62397500
    Email: mjaeger@partner.eso.org

    At NASA/Chandra
    Media contacts:
    Felicia Chou / Sean Potter
    Headquarters, Washington
    202-358-0257 / 1536
    felicia.chou@nasa.gov / sean.potter@nasa.gov

    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.
    617-496-7998
    mwatzke@cfa.harvard.edu

    1

    Astrophysicists have taken a major step forward in understanding how supermassive black holes formed. Using data from Hubble and two other space telescopes, Italian researchers have found the best evidence yet for the seeds that ultimately grow into these cosmic giants.

    For years astronomers have debated how the earliest generation of supermassive black holes formed very quickly, relatively speaking, after the Big Bang. Now, an Italian team has identified two objects in the early Universe that seem to be the origin of these early supermassive black holes. The two objects represent the most promising black hole seed candidates found so far [1].

    The group used computer models and applied a new analysis method to data from the NASA Chandra X-ray Observatory, the NASA/ESA Hubble Space Telescope, and the NASA Spitzer Space Telescope to find and identify the two objects. Both of these newly discovered black hole seed candidates are seen less than a billion years after the Big Bang and have an initial mass of about 100 000 times the Sun.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    “Our discovery, if confirmed, would explain how these monster black holes were born,” said Fabio Pacucci, lead author of the study, of Scuola Normale Superiore in Pisa, Italy.

    This new result helps to explain why we see supermassive black holes less than one billion years after the Big Bang.

    There are two main theories to explain the formation of supermassive black holes in the early Universe. One assumes that the seeds grow out of black holes with a mass about ten to a hundred times greater than our Sun, as expected for the collapse of a massive star. The black hole seeds then grew through mergers with other small black holes and by pulling in gas from their surroundings. However, they would have to grow at an unusually high rate to reach the mass of supermassive black holes already discovered in the billion years young Universe.

    The new findings support another scenario where at least some very massive black hole seeds with 100 000 times the mass of the Sun formed directly when a massive cloud of gas collapses [2]. In this case the growth of the black holes would be jump started, and would proceed more quickly.

    “There is a lot of controversy over which path these black holes take,” said co-author Andrea Ferrara also of Scuola Normale Superiore. “Our work suggests we are converging on one answer, where black holes start big and grow at the normal rate, rather than starting small and growing at a very fast rate.”

    Andrea Grazian, a co-author from the National Institute for Astrophysics in Italy explains: “Black hole seeds are extremely hard to find and confirming their detection is very difficult. However, we think our research has uncovered the two best candidates so far.”

    Even though both black hole seed candidates match the theoretical predictions, further observations are needed to confirm their true nature. To fully distinguish between the two formation theories, it will also be necessary to find more candidates.

    These results* will appear in the June 21st issue of the Monthly Notices of the Royal Astronomical Society and is available online. The authors of the paper are Fabio Pacucci (SNS, Italy), Andrea Ferrara (SNS), Andrea Grazian (INAF), Fabrizio Fiore (INAF), Emaneule Giallongo (INAF), and Simonetta Puccetti (ASI Science Data Center).

    The team plans to conduct follow-up observations in X-rays and in the infrared range to check whether the two objects have more of the properties expected for black hole seeds. Upcoming observatories, like the NASA/ESA/CSA James Webb Space Telescope and the European Extremely Large Telescope will certainly mark a breakthrough in this field, by detecting even smaller and more distant black holes.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile
    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile

    Notes

    [1] Supermassive black holes contain millions or even billions of times the mass of the Sun. In the modern Universe they can be found in the centre of nearly all large galaxies, including the Milky Way.

    Sag A*  NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way
    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    The supermassive black hole in the centre of the Milky Way has a mass of four million solar masses. The two black hole seed candidates would also be the progenitors of two of the modern supermassive black holes.

    [2] Black hole seeds created through the collapse of a massive cloud of gas bypass any other intermediate phases such as the formation and subsequent destruction of a massive star.

    The team of scientists in this study consists of Fabio Pacucci (Scuola Normale Superiore, Italy), Andrea Ferrara (Scuola Normale Superiore, Italy), Andrea Grazian (INAF, Italy), Fabrizio Fiore (INAF, Italy), Emanuele Giallongo (INAF, Italy), Simonetta Puccetti (ASDC-ASI, Italy)

    NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

    NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate in Washington, D.C. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

    *Science paper:
    First Identification of Direct Collapse Black Hole Candidates in the Early Universe in CANDELS/GOODS-S

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 2:35 pm on May 24, 2016 Permalink | Reply
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    From LBL: “Hunting for Dark Matter’s ‘Hidden Valley’ ” Women in Science 

    Berkeley Logo

    Berkeley Lab

    May 24, 2016
    Glenn Roberts Jr.
    510-486-5582
    geroberts@lbl.gov

    1
    Kathryn Zurek (Credit: Roy Kaltschmidt/Berkeley Lab)

    Kathryn Zurek realized a decade ago that we may be searching in the wrong places for clues to one of the universe’s greatest unsolved mysteries: dark matter. Despite making up an estimated 85 percent of the total mass of the universe, we haven’t yet figured out what it’s made of.

    Now, Zurek, a theoretical physicist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), says thanks to extraordinary improvements in experimental sensitivity, “We increasingly know where not to look.” In 2006, during grad school, Zurek began to explore the concept of a new “Hidden Valley” model for physics that could hold all of the answers to dark matter.

    “I noticed that from a model-builder’s point of view that dark matter was extraordinarily undeveloped,” she said. It seemed as though scientists were figuratively hunting in the dark for answers. “People were focused on models of just two classes of dark matter candidates, rather than a much broader array of possibilities.”

    Physicist and author Alan Lightman has described dark matter as an “invisible elephant in the room”—you know it’s there because of the dent it’s making in the floorboards but you can’t see or touch it. Likewise, physicists can infer that dark matter exists in huge supply compared to normal matter because of its gravitational effects, which far exceed those expected from the matter we can see in space.

    Since physicist Fritz Zwicky in 1933 measured this major discrepancy in the gravitational mass of a galaxy cluster, that he concluded was due to dark matter, the search for what dark matter is really made of has taken many forms: from deep-underground detectors to space- and ground-based observatories, balloon-borne missions and powerful particle accelerator experiments.

    While there have been some candidate signals and hints, and numerous experiments have narrowed the range of energies and masses at which we are now looking for dark matter particles, the scientific community hasn’t yet embraced a dark matter discovery.

    3 Knowns and 3 Unknowns about Dark Matter

    What’s known
    1. We can observe its effects.
    2

    2. It is abundant.
    3
    It makes up about 85 percent of the total mass of the universe, and about 27 percent of the universe’s total mass and energy.

    3. We know more about what dark matter is not.

    Increasingly sensitive detectors are lowering the possible rate at which dark mark matter particles can interact with normal matter.
    4
    This chart shows the sensitivity limits (solid-line curves) of various experiments searching for signs of theoretical dark matter particles known as WIMPs (weakly interacting massive particles). The shaded closed contours show hints of WIMP signals. The thin dashed and dotted curves show projections for future U.S.-led dark matter direct-detection experiments expected in the next decade, and the thick dashed curve (orange) shows a so-called “neutrino floor” where neutrino-related signals can obscure the direct detection of dark matter particles. (Credit: Snowmass report, 2013.)

    What’s unknown

    1. Is it made up of one particle or many particles?
    6
    (Credit: Pixabay/CreativeMagic)

    Could dark matter be composed of an entire family of particles, such as a theorized “hidden valley” or “dark sector?”
    2. Are there “dark forces” acting on dark matter?

    Are there forces beyond gravity and other known forces that act on dark matter but not on ordinary matter, and can dark matter interact with itself?
    7
    This image from the NASA/ESA Hubble Space Telescope shows the galaxy cluster Abell 3827. The blue structures surrounding the central galaxies are views of a more distant galaxy behind the cluster that has been distorted by an effect known as gravitational lensing. Observations of the central four merging galaxies in this image have provided hints that the dark matter around one of the galaxies is not moving with the galaxy itself, possibly indicating the occurrence of an unknown type of dark matter interaction. (Credit: ESO)

    3. Is there dark antimatter?
    8
    A computerized visualization showing the possible large-scale structure of dark matter in the universe. (Credit: Amit Chourasia and Steve Cutchin/NPACI Visualization Services; Enzo)

    In 2006, as a graduate student at the University of Washington, Zurek and collaborator Matthew J. Strassler, a faculty member, published a paper*, “Echoes of a Hidden Valley at Hadron Colliders,” that considered the possibility of new physics such as the existence of a new group of light (low-mass), long-lived particles that could possibly be revealed at CERN’s Large Hadron Collider, the machine that would later enable the Nobel Prize-winning discovery of the Higgs boson in 2012.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Some of the scientifically popular hypothetical particle candidates for dark matter are WIMPs (weakly interacting massive particles) and axions (very-low-mass particles). But the possibility of a rich and overlooked mix of light particles was compelling for Zurek, who began to construct models to test out the theory.

    “If you had a low-mass hidden sector, you could ‘stuff’ all kinds of things inside of it,” she said. “That really set me up to start thinking about complex dark sectors, which I did as a postdoc.”

    Looking back to 2008, Zurek said she felt like someone carrying around a sandwich board proclaiming that dark matter could be a stranger, manifold thing than most had imagined. “I was like that little guy with the sign.”

    By coincidence, the so-called “PAMELA anomaly” was revealed that same year; data from the PAMELA space mission in 2008 had found an unexpected excess of positrons, the antimatter counterpart to electrons, at certain energies. This measurement excited physicists as a possible particle signature from the decay of dark matter, and the excess defied standard dark matter theories and opened the door to new ones.

    Now that the concept of “hidden valleys” or “dark sectors” with myriad particles making up dark matter is gaining steam among scientists—Zurek spoke in late April at a three-day “Workshop on Dark Sectors”—she said she feels gratified to have worked on some of the early theoretical models.

    “It’s great in one sense because these ideas really got traction,” Zurek said. “The fact that there were these experimental anomalies, that was sort of a coincidence. As a second- or third-year postdoc, this was like ‘my program’—this was the thing I was pushing. It suddenly got very popular.”

    On an afternoon in late April, Zurek and her student Katelin Schutz sat together waiting to press the button to submit a new paper on a proposal to tease out a signal for light dark matter particles using an exotic, supercooled liquid known as superfluid helium. In the paper, they explain how this form of helium can probe for signals of “super light dark matter,” with an energy signature well below the reach of today’s experiments.

    They are also working with Dan McKinsey, a Berkeley Lab scientist and UC Berkeley physics professor who is a superfluid helium expert, on possible designs for an experiment.

    Most popular theories of WIMPs suggest a mass around 100 times the mass of a proton, a particle found at an atom’s core, for example, but a superfluid helium detector could be sensitive to masses many orders of magnitude smaller, she said.

    Are we any closer to finding dark matter?

    Zurek said she is surprised we haven’t yet made a discovery, but she is encouraged by the increasing sensitivity of experiments, and she said Berkeley Lab has particular expertise in high-precision detectors that will hopefully ensure its role in future experiments.

    “There is a cross-fertilization from different fields of physics that has really blossomed in the last several years,” Zurek also said. She joined Berkeley Lab in 2014 after serving as an associate professor at University of Michigan, and has also spent time at the Institute for Advanced Study in Princeton, N.J.; and at Fermi National Accelerator Laboratory’s Particle Astrophysics Center.

    Besides dark matter research, Zurek works on problems related to possible new physics at play in the infant universe and in the evolution of the universe’s structure, for example Her work often is at the intersection of particle physics experiments and astrophysics observations.

    Hard problems like the dark matter mystery are what drew her to physics at an early age, when she enrolled in college at the age of 15.

    “I wanted to understand how the universe worked. Plus, physics was hard and I liked that. I thought it was the hardest thing you could do, which I found very appealing. I decided at 15 that I wanted to make it a career, and I just never looked back,” she said.

    She knew, too, that she didn’t want to work directly on big science experiments. “I had always been fascinated about ideas: Ideas in philosophy, and the interplay between music and philosophy and physics.”

    She is a classical pianist with the ability to improvise melodies—she refers to this as a “tremendous intuition in how to make sounds”—and she still turns to music when confronting a physics problem. “When you’re really stuck on a problem you never stop thinking about it. Sometimes playing the piano helps.”

    When outdoors, Zurek enjoys sailing, hiking and alpine-style climbing—complete with ice axe and crampons—atop peaks such as Mount Rainer and Mount Shasta.

    As for the trail ahead in the dark matter hunt, Zurek said it’s important to be nimble and to expect the unexpected.

    “You don’t want to put yourself at a dead-end where you’re not exploring other possibilities,” she said.

    “The thing we don’t want to forget is: We don’t know what dark matter is. You have to have room for exploratory experiments, and you probably need a lot of them.”

    Learn more about Kathryn Zurek’s research: https://www.kzurek.theory.lbl.gov/.

    *Science paper:
    Echoes of a Hidden Valley at Hadron Colliders

    See the full article here .

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    A U.S. Department of Energy National Laboratory Operated by the University of California

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  • richardmitnick 5:32 pm on May 23, 2016 Permalink | Reply
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    From Goddard: “NASA: Solar Storms May Have Been Key to Life on Earth” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    May 23, 2016
    Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    karen.c.fox@nasa.gov

    Solar eruption 2012 by NASA's Solar Dynamic Observatory SDO
    Solar eruption 2012 by NASA’s Solar Dynamic Observatory SDO

    Our sun’s adolescence was stormy—and new evidence shows that these tempests may have been just the key to seeding life as we know it.

    Some 4 billion years ago, the sun shone with only about three-quarters the brightness we see today, but its surface roiled with giant eruptions spewing enormous amounts of solar material and radiation out into space. These powerful solar explosions may have provided the crucial energy needed to warm Earth, despite the sun’s faintness. The eruptions also may have furnished the energy needed to turn simple molecules into the complex molecules such as RNA and DNA that were necessary for life. The research was published* in Nature Geoscience on May 23, 2016, by a team of scientists from NASA.


    Access mp4 video here .

    Understanding what conditions were necessary for life on our planet helps us both trace the origins of life on Earth and guide the search for life on other planets. Until now, however, fully mapping Earth’s evolution has been hindered by the simple fact that the young sun wasn’t luminous enough to warm Earth.

    “Back then, Earth received only about 70 percent of the energy from the sun than it does today,” said Vladimir Airapetian, lead author of the paper and a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That means Earth should have been an icy ball. Instead, geological evidence says it was a warm globe with liquid water. We call this the Faint Young Sun Paradox. Our new research shows that solar storms could have been central to warming Earth.”

    Scientists are able to piece together the history of the sun by searching for similar stars in our galaxy. By placing these sun-like stars in order according to their age, the stars appear as a functional timeline of how our own sun evolved. It is from this kind of data that scientists know the sun was fainter 4 billion years ago. Such studies also show that young stars frequently produce powerful flares – giant bursts of light and radiation — similar to the flares we see on our own sun today. Such flares are often accompanied by huge clouds of solar material, called coronal mass ejections, or CMEs, which erupt out into space.

    NASA’s Kepler mission found stars that resemble our sun about a few million years after its birth.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    The Kepler data showed many examples of what are called “superflares” – enormous explosions so rare today that we only experience them once every 100 years or so. Yet the Kepler data also show these youngsters producing as many as ten superflares a day.

    While our sun still produces flares and CMEs, they are not so frequent or intense.

    What’s more, Earth today has a strong magnetic field that helps keep the bulk of the energy from such space weather from reaching Earth.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase
    Magnetosphere of Earth, original bitmap from NASA

    Space weather can, however, significantly disturb a magnetic bubble around our planet, the magnetosphere, a phenomenon referred to as geomagnetic storms that can affect radio communications and our satellites in space. It also creates auroras – most often in a narrow region near the poles where Earth’s magnetic fields bow down to touch the planet.

    Our young Earth, however, had a weaker magnetic field, with a much wider footprint near the poles.

    “Our calculations show that you would have regularly seen auroras all the way down in South Carolina,” says Airapetian. “And as the particles from the space weather traveled down the magnetic field lines, they would have slammed into abundant nitrogen molecules in the atmosphere. Changing the atmosphere’s chemistry turns out to have made all the difference for life on Earth.”

    The atmosphere of early Earth was also different than it is now: Molecular nitrogen – that is, two nitrogen atoms bound together into a molecule – made up 90 percent of the atmosphere, compared to only 78 percent today. As energetic particles slammed into these nitrogen molecules, the impact broke them up into individual nitrogen atoms. They, in turn, collided with carbon dioxide, separating those molecules into carbon monoxide and oxygen.

    The free-floating nitrogen and oxygen combined into nitrous oxide, which is a powerful greenhouse gas. When it comes to warming the atmosphere, nitrous oxide is some 300 times more powerful than carbon dioxide. The teams’ calculations show that if the early atmosphere housed less than one percent as much nitrous oxide as it did carbon dioxide, it would warm the planet enough for liquid water to exist.

    This newly discovered constant influx of solar particles to early Earth may have done more than just warm the atmosphere, it may also have provided the energy needed to make complex chemicals. In a planet scattered evenly with simple molecules, it takes a huge amount of incoming energy to create the complex molecules such as RNA and DNA that eventually seeded life.

    While enough energy appears to be hugely important for a growing planet, too much would also be an issue — a constant chain of solar eruptions producing showers of particle radiation can be quite detrimental. Such an onslaught of magnetic clouds can rip off a planet’s atmosphere if the magnetosphere is too weak. Understanding these kinds of balances help scientists determine what kinds of stars and what kinds of planets could be hospitable for life.

    “We want to gather all this information together, how close a planet is to the star, how energetic the star is, how strong the planet’s magnetosphere is in order to help search for habitable planets around stars near our own and throughout the galaxy,” said William Danchi, principal investigator of the project at Goddard and a co-author on the paper. “This work includes scientists from many fields — those who study the sun, the stars, the planets, chemistry and biology. Working together we can create a robust description of what the early days of our home planet looked like – and where life might exist elsewhere.”

    For more information about the Kepler mission, visit:

    http://www.nasa.gov/kepler

    *Science paper:
    Prebiotic chemistry and atmospheric warming of early Earth by an active young Sun

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
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  • richardmitnick 4:56 pm on May 23, 2016 Permalink | Reply
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    From U Texas at Austin: “Making Virus Sensors Cheap and Simple: New Method Detects Single Viruses” 

    U Texas Austin bloc

    University of Texas at Austin

    23 May 2016
    Marc G Airhart

    Scientists at The University of Texas at Austin have developed a new method to rapidly detect a single virus in urine, as reported* this week in the journal Proceedings of the National Academy of Sciences.

    1
    Researchers at The University of Texas at Austin demonstrated the ability to detect single viruses in a solution containing murine cytomegalovirus (MCMV). The single virus in this image is a human cytomegalovirus, a cousin of MCMV. It was obtained by chilling a sample down with liquid nitrogen and exposing it to high-energy electrons. Image courtesy of Jean-Yves Sgro, U. of Wisconsin-Madison (EMD-5696 data Dai, XH et al., 2013)

    Although the technique presently works on just one virus, scientists say it could be adapted to detect a range of viruses that plague humans including Ebola, Zika and HIV.

    “The ultimate goal is to build a cheap, easy-to-use device to take into the field and measure the presence of a virus like Ebola in people on the spot,” says Jeffrey Dick, a chemistry graduate student and co-lead author of the study. “While we are still pretty far from this, this work is a leap in the right direction.”

    The other co-lead author is Adam Hilterbrand, a microbiology graduate student.

    The new method is highly selective, meaning it is only sensitive to one type of virus, filtering out possible false negatives caused by other viruses or contaminants.

    There are two other commonly used methods for detecting viruses in biological samples, but they have drawbacks. One requires a much higher concentration of viruses, and the other requires samples to be purified to remove contaminants. The new method, however, can be used with urine straight from a person or animal.

    The other co-authors are Lauren Strawsine, a postdoctoral fellow in chemistry; Jason Upton, an assistant professor of molecular biosciences; and Allen Bard, professor of chemistry and director of the Center for Electrochemistry.

    The researchers demonstrated their new technique on a virus that belongs to the same family as the herpes virus, called murine cytomegalovirus (MCMV). To detect individual viruses, the team places an electrode — a wire that conducts electricity, in this case, one that is thinner than a human cell — in a sample of mouse urine. They then add to the urine some special molecules made up of enzymes and antibodies that naturally stick to the virus of interest. When all three stick together and then bump into the electrode, there’s a spike in electric current that can be easily detected.

    The researchers say their new method still needs refinement. For example, the electrodes become less sensitive over time because a host of other naturally occurring compounds stick to them, leaving less surface area for viruses to interact with them. To be practical, the process will also need to be engineered into a compact and rugged device that can operate in a range of real-world environments.

    Support for this research was provided by the National Science Foundation, the Welch Foundation and the Cancer Prevention & Research Institute of Texas.

    *Science paper:
    Enzymatically enhanced collisions on ultramicroelectrodes for specific and rapid detection of individual viruses

    See the full article here .

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    U Texas Arlington Campus

    In 1839, the Congress of the Republic of Texas ordered that a site be set aside to meet the state’s higher education needs. After a series of delays over the next several decades, the state legislature reinvigorated the project in 1876, calling for the establishment of a “university of the first class.” Austin was selected as the site for the new university in 1881, and construction began on the original Main Building in November 1882. Less than one year later, on Sept. 15, 1883, The University of Texas at Austin opened with one building, eight professors, one proctor, and 221 students — and a mission to change the world. Today, UT Austin is a world-renowned higher education, research, and public service institution serving more than 51,000 students annually through 18 top-ranked colleges and schools.

     
  • richardmitnick 4:39 pm on May 23, 2016 Permalink | Reply
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    From Rockefeller: “New method gives scientists a better look at how HIV infects and takes over its host cells” 

    Rockefeller U bloc

    Rockefeller University

    May 23, 2016
    No writer credit found

    1
    Cell to cell: When HIV infects a cell, it programs the cell to express the viral protein Env, which the virus uses to spread to neighboring cells. Above, Env (red) produced by one infected cell has recruited other, uninfected cells, causing them to fuse, and their nuclei (blue) to cluster.

    Viruses attack cells and commandeer their machinery in a complex and carefully orchestrated invasion. Scientists have longed probed this process for insights into biology and disease, but essential details still remain out of reach.

    A new approach, developed by a team of researchers led by the Rockefeller University and the Aaron Diamond AIDS Research Center (ADARC), offers an unprecedented view of how a virus infects and appropriates a host cell, step by step. In research published* May 23 in Nature Microbiology, they applied their method to HIV, a virus whose genome is less than 100,000 the size of ours.

    “HIV is truly an expert at living large on a small budget,” says first author Yang Luo, a postdoc at ADARC and a former graduate student at Rockefeller University. “We asked the question, how does such a compact virus manipulate the host cell to gain entry and replicate itself, all while escaping the immune system?”

    Mapping HIV’s ‘interactome’

    The study focused on two viral proteins known to bring about HIV’s infection of human white blood cells. The first one, called envelope or Env, sits on the surface of the virus and, by binding to receptors on the host cell, helps the membrane that encapsulates the virus fuse with the cell’s outer membrane. A second protein, Vif, destroys an enzyme that host cells produce to defend themselves against the virus.

    In an effort to better understand how these two proteins function, the team wanted to map their interactome—meaning all the proteins with which they associate within a host cell. To accomplish this, the researchers needed to devise a way to isolate clusters of interacting proteins from cells during different stages of infection. Such experiments can be done by introducing a genetic sequence into the viral genome—a “tag” that acts like a piece of molecular Velcro, allowing one viral protein to be yanked out along with all the other proteins associated with it.

    2

    It sounds simple, but making it work took a decade.

    “Inserting a tag sequence into small viruses is a challenge to begin with,” says corresponding author Mark Muesing, a principal investigator at ADARC. “If you disrupt their nucleic acid and protein sequences, you can easily compromise the virus’s ability to replicate. And HIV represents a particular challenge because it can quickly revert back to its original sequence.”

    “We developed a technique to find places in the HIV genome where we can insert stable tags without affecting the virus’s capacity to proliferate. In effect, this allowed us to expand cultures of the infected cells along with the tagged viral protein,” he added.

    The host’s contribution

    Next, the researchers infected human cells with viruses carrying the tagged protein sequences, and were able to pull out and identify a large number of host proteins directly during the infectious process. This provided the first evidence that many previously underappreciated host proteins interact with the viral machinery during replication.

    “Imagine you have a factory assembly line where only one component of, say, the stamping machine, actually touches the product,” says co-author Michael Rout, professor and head of Rockefeller’s Laboratory of Cellular and Structural Biology. “Other parts support and power the stamp. Likewise, within an infected cell, we can identify the components of a particular cellular machine, not just the piece that comes in contact with the viral protein.”

    “Every host protein we pull out generates new questions,” adds co-first author Erica Jacobs, a research associate in Brian Chait’s lab. “Does it help the virus invade and coopt the host to replicate itself? Or does it harm it? The answers will not only help us understand the virus, but also shed light on our cells’ ability to defend themselves.”

    One important discovery has already emerged from the lists of proteins. Viruses, including HIV, often attack as so-called virions, which are individual packets of protein and genetic code. But they can also pass directly from an infected to an uninfected cell, a more effective mode of transmission. To do so, the virus appears to use host proteins to construct a platform, a close junctional surface, between cells.

    From the list of proteins that interact with Env, the researchers have identified cellular proteins predicted to contribute to this platform between cells. Because this route of transmission protects the virus in a sequestered environment, away from host defenses, the new findings may aid in the development of future anti-HIV therapies.

    A live infection, step by step

    According to co-author Brian Chait, Camille and Henry Dreyfus Professor and head of the Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, the new approach offers a rare glimpse into the process by which HIV invades and resurrects itself within a cell.

    “Often, studies of this sort are done with viral proteins in the absence of a true viral infection “However, because viral infections are exquisitely orchestrated events, you are likely to miss all kinds of important details if you study the action of these proteins out of their proper context.”

    “Deciphering the intricacies of virus-host protein interactions in space and time during the progression of an infection is remarkably powerful” says co-author Ileana Cristea, an associate professor of molecular biology at Princeton University. “The challenge is to discover which precise interactions are the critical ones.”

    Todd Greco, a co-first author, and an associate research scholar and lecturer in molecular biology in Cristea’s lab, says that “even for host proteins within the same family, their relative stability within HIV-1 protein complexes can be very different. More broadly, by understanding these mechanisms we will better understand the coordinated responses of cells.”

    *Science paper:
    HIV–host interactome revealed directly from infected cells

    See the full article here .

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    Rockefeller U Campus

    The Rockefeller University is a world-renowned center for research and graduate education in the biomedical sciences, chemistry, bioinformatics and physics. The university’s 76 laboratories conduct both clinical and basic research and study a diverse range of biological and biomedical problems with the mission of improving the understanding of life for the benefit of humanity.

    Founded in 1901 by John D. Rockefeller, the Rockefeller Institute for Medical Research was the country’s first institution devoted exclusively to biomedical research. The Rockefeller University Hospital was founded in 1910 as the first hospital devoted exclusively to clinical research. In the 1950s, the institute expanded its mission to include graduate education and began training new generations of scientists to become research leaders around the world. In 1965, it was renamed The Rockefeller University.

     
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