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  • richardmitnick 11:15 am on October 31, 2014 Permalink | Reply
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    From NASA/JPL: “Specular Spectacular” 

    JPL

    October 30, 2014
    No Writer Credit

    This near-infrared, color mosaic from NASA’s Cassini spacecraft shows the sun glinting off of Titan’s north polar seas. While Cassini has captured, separately, views of the polar seas and the sun glinting off of them in the past, this is the first time both have been seen together in the same view.

    titan
    Image credit: NASA/JPL-Caltech/University of Arizona/University of Idaho

    NASA Cassini Spacecraft
    NASA/Cassini

    The sunglint, also called a specular reflection, is the bright area near the 11 o’clock position at upper left. This mirror-like reflection, known as the specular point, is in the south of Titan’s largest sea, http://en.wikipedia.org/wiki/Kraken_Mare, just north of an island archipelago separating two separate parts of the sea.

    This particular sunglint was so bright as to saturate the detector of Cassini’s Visual and Infrared Mapping Spectrometer (VIMS) instrument, which captures the view. It is also the sunglint seen with the highest observation elevation so far — the sun was a full 40 degrees above the horizon as seen from Kraken Mare at this time — much higher than the 22 degrees seen in PIA18433. Because it was so bright, this glint was visible through the haze at much lower wavelengths than before, down to 1.3 microns.

    The southern portion of Kraken Mare (the area surrounding the specular feature toward upper left) displays a “bathtub ring” — a bright margin of evaporate deposits — which indicates that the sea was larger at some point in the past and has become smaller due to evaporation. The deposits are material left behind after the methane & ethane liquid evaporates, somewhat akin to the saline crust on a salt flat.

    The highest resolution data from this flyby — the area seen immediately to the right of the sunglint — cover the labyrinth of channels that connect Kraken Mare to another large sea, Ligeia Mare. Ligeia Mare itself is partially covered in its northern reaches by a bright, arrow-shaped complex of clouds. The clouds are made of liquid methane droplets, and could be actively refilling the lakes with rainfall.

    The view was acquired during Cassini’s August 21, 2014, flyby of Titan, also referred to as “T104″ by the Cassini team.

    The view contains real color information, although it is not the natural color the human eye would see. Here, red in the image corresponds to 5.0 microns, green to 2.0 microns, and blue to 1.3 microns. These wavelengths correspond to atmospheric windows through which Titan’s surface is visible.

    The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. The VIMS team is based at the University of Arizona in Tucson.

    More information about Cassini is available at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

    See the full article, with other material, here.

    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 10:49 am on October 31, 2014 Permalink | Reply
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    From SPACE.com: “Earth’s Water Existed 135 Million Years Earlier than Thought” 

    space-dot-com logo

    SPACE.com

    October 30, 2014
    Calla Cofield

    The water that supports life on Earth may have been on the planet much earlier than scientists previously thought, new research suggests.

    space
    An illustration of the early solar system shows proto-Earth, proto-Mars, Vesta within the asteroid belt, and proto-Jupiter. The dashed white line represents the “snow line” boundary for water ice in the solar system.
    Credit: Jack Cook, Woods Hole Oceanographic Institution

    While the environmental conditions in Earth’s early years made it impossible for water to remain on the planet’s surface, scientists have found evidence that the ingredients for water were protectively stored inside rocky bodies near our planet — and maybe inside Earth itself. The new findings suggest that there was water in the inner solar system 135 million years earlier than previous evidence had shown.

    “Our findings show the earliest evidence of water in the inner solar system,” said Adam Sarafian, a Ph.D. student at the Woods Hole Research Center in Massachusetts and lead author of the new study.

    Meteorites from an asteroid

    The smoking gun appears inside meteorites that once belonged to the asteroid Vesta, one of the largest members of the asteroid belt that sits between Jupiter and Mars. Meteorites from Vesta —dark chunks of cooled magma often as big as grapefruits — continue to be found in Antarctica. Previous analysis found no water or water-forming ingredients in those meteorites. But Sarafian and his colleagues zoomed in on the molecular contents of the meteorites, and found trace amounts of hydrogen-oxygen molecules.

    vesta
    This image of the giant asteroid Vesta was captured by NASA’s Dawn spacecraft on Sept. 5, 2012.
    Credit: NASA

    NASA Dawn Spacecraft
    NASA Dawn schematic
    NASA/Dawn

    More than 4.5 billion years ago — or about 15 million years after solid bodies began to form around the young sun — water existed in the outer, cooler parts of the solar system, previous studies have shown. But in the inner solar system, where Vesta and a young Earth resided, temperatures were far too hot and solar winds would send any water vapor to the outer regions of the solar system.

    While the Earth grew and changed over the next 4 billion years or so, Vesta remained frozen in time, according to Sarafian.

    A chemical fingerprint

    Vesta also has the same chemical fingerprint as the Earth. In other words, scientists have previously shown that the nitrogen on Vesta likely originated from the same source as the nitrogen on Earth. Some bodies in the solar system, like the sun or comets, have different chemical signatures. According to Sarafian, the new study shows that Vesta and Earth also share a hydrogen chemical signature.

    The Earth also shares a chemical fingerprint with the moon, which, like Vesta, gives scientists a window to the past. Scientists have found traces of water in lunar rocks, which provides evidence that the life-giving liquid was in the inner solar system as early as 150 million years after the birth of the solar system. The Vesta samples predate the lunar samples by 135 million years.

    The jump back in time is significant, says Sarafian, because during those first 150 million years, the inner solar system was considerably hotter and more hostile than it was later on. Earth would have experienced major impacts from flying debris (it was potentially such an impact that broke off a portion of the Earth and formed the moon). Many scientists have suspect that through those big impacts and high temperatures, it would make sense for the hydrogen to turn into vapor and be blown out into space.

    “The planets held on to the water somehow,” Sarafian said. “That’s going to make people rethink how planets are made.”

    Water from icy bodies

    Sarafian said the work supports the view that the water came from icy bodies near Jupiter. The newly forming gas giant likely flung the chunks of rock and ice inward. Jupiter would have been located beyond what’s known as the “snow line,” or the point beyond which temperatures were cool enough for water to condense into liquid or solid form, he said.

    “There are models that predict that icy bodies from the outer solar system, around the Jupiter area, probably got flung into the inner solar system,” Sarafian said. “But there was just no evidence for it. There wasn’t any data to support the model. And our study is supporting it.”

    Jeremy Boyce, a geochemist at UCLA who was not involved in the new study but has collaborated with two of the study’s authors on other works, said the new study’s claims of water in the early inner solar system are robust. But he added that it’s still unclear just how much water was present. It’s likely that to make the oceans present on Earth today, more water was delivered to Earth later in its life.

    “The extent to which [the early water] relates to water we see on the surface of the Earth is an open question,” said Boyce. “What water was present in the early Earth and what arrived later — I don’t think we know that yet.”

    The new study is detailed in the Oct. 31 issue of the journal Science.

    See the full article here.

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  • richardmitnick 10:31 am on October 31, 2014 Permalink | Reply
    Tags: , Basic Research, , , Fermilab Today, , ,   

    From FNAL- “Frontier Science Result: CMS Boosted W’s” 


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

    Friday, Oct. 31, 2014

    FNAL Don Lincoln
    Don Lincoln

    Today’s article covers an interesting topic. It’s interesting not because it explores new physics, but because of how it reveals some of the mundane aspects of research at the LHC. It also shows how the high energy of the LHC makes certain topics harder to study than they were during the good old days at lower-energy accelerators.

    At the LHC, quarks or gluons are scattered out of the collision. It’s the most common thing that happens at the LHC. Regular readers of this column know that it is impossible to see isolated quarks and gluons and that these particles convert into jets as they exit the collision. Jets are collimated streams of particles that have more or less the same energy as the parent quark or gluon. Interactions that produce jets are governed by the strong force.

    map
    In the green region, we show what a W boson looks like before it decays. Moving left to right, the boson is created with more and more momentum. In the yellow region, we repeat the exercise, this time looking at the same W boson after it decays into quarks, which have then turned into jets. Finally in the pink region, we look at a jet originating from a quark or gluon. This looks much like a high-momentum W boson decaying into quarks. Because ordinary jets are so much more common, this highlights the difficulty inherent in finding high-momentum W bosons that decay into jets.
    No image credit

    Things get more interesting when a W boson is produced. One reason for this is that making a W boson requires the involvement of the electroweak force, which is needed for the decay of heavy quarks. Thus studies of W bosons are important for subjects such as the production of the top quark, which is the heaviest quark. W bosons are also found in some decays of the Higgs boson.

    A W boson most often decays into two light quarks, and when it decays, it flings the light quarks into two different directions, which can be seen as two jets.

    But there’s a complication in this scenario at the LHC, where the W bosons are produced with so much momentum that it affects the spatial distribution of particles in those two jets. As the momentum of the W boson increases, the two jets get closer together and eventually merge into a single jet.

    As mentioned earlier, individual jets are much more commonly made using the strong force. So when one sees a jet, it is very hard to identify it as coming from a W boson, which involves the electroweak force. Since identifying the existence of W bosons is very important for certain discoveries, CMS scientists needed to figure out how to tell quark- or gluon-initiated jets from the W-boson-initiated jets. So they devised algorithms that could identify when a jet contained two lumps of energy rather than one. If there were two lumps, the jet was more likely to come from the decay of a W boson.

    CERN CMS New
    CMS

    In today’s paper, CMS scientists explored algorithms and studied variables one can extract from the data to identify single jets that originated from the decay of W bosons. The data agreed reasonably well with calculations, and the techniques they devised will be very helpful for future analyses involving W bosons. In addition, the same basic technique can be extended to other interesting signatures, such as the decay of Z and Higgs bosons.

    See the full article here.

    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.

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  • richardmitnick 4:21 pm on October 30, 2014 Permalink | Reply
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    From phys.org: “Existence of a group of ‘quiet’ quasars confirmed” 

    physdotorg
    phys.org

    Oct 29, 2014
    Provided by Institute of Astrophysics of Andalusia

    Aeons ago, the universe was different: mergers of galaxies were common and gigantic black holes with masses equivalent to billions of times that of the Sun formed in their nuclei. As they captured the surrounding gas, these black holes emitted energy. Known as quasars, these very distant and tremendously high energy objects have local relatives with much lower energy whose existence raises numerous questions: are there also such “quiet” quasars at much larger distances? Are the latter dying versions of the former or are they completely different?

    qua
    An artist´s view of the heart of a quasar. Credit: NASA

    Light from distant quasars takes billions of years to reach us, so when we detect it we are actually looking at the universe as it was a long time ago. “Astronomers have always wanted to compare past and present, but it has been almost impossible because at great distances we can only see the brightest objects and nearby such objects no longer exist”, says Jack W. Sulentic, astronomer at the Institute of Astrophysics of Andalusia (IAA-CSIC), who is leading the research. “Until now we have compared very luminous distant quasars with weaker ones closeby, which is tantamount to comparing household light bulbs with the lights in a football stadium”. Now we are able to detect the household light bulbs very far away in the distant past.

    The more distant, the more luminous?

    Quasars appear to evolve with distance: the farther away one gets, the brighter they are. This could indicate that quasars extinguish over time or it could be the result of a simple observational bias masking a different reality: that gigantic quasars evolving very quickly, most of them already extinct, coexist with a quiet population that evolves at a much slower rhythm but which our technological limitations do not yet allow us to research.

    To solve this riddle it was necessary to look for low luminosity quasars at enormous distances and to compare their characteristics with those of nearby quasars of equal luminosity, something thus far almost impossible to do, because it requires observing objects about a hundreds of times weaker than those we are used to studying at those distances.

    The tremendous light-gathering power of the GTC telescope, has recently enabled Sulentic and his team to obtain for the first time spectroscopic data from distant, low luminosity quasars similar to typical nearby ones. Data reliable enough to establish essential parameters such as chemical composition, mass of the central black hole or rate at which it absorbs matter.

    Grand Telescope de Canaries
    Grand Telescope de Canaries interior
    GTC

    “We have been able to confirm that, indeed, apart from the highly energetic and rapidly evolving quasars, there is another population that evolves slowly. This population of quasars appears to follow the quasar main sequence discovered by Sulentic and colleagues in 2000. There does not even seem to be a strong relation between this type of quasars, which we see in our environment and those “monsters” that started to glow more than ten billion years ago”, says Ascensión del Olmo another IAA-CSIC researcher taking part in the study.

    They have, nonetheless, found differences in this population of quiet quasars. “The local quasars present a higher proportion of heavy elements such as aluminium, iron or magnesium, than the distant relatives, which most likely reflects enrichment by the birth and death of successive generations of stars,” says Jack W. Sulentic (IAA-CSIC). “This result is an excellent example of the new perspectives on the universe which the new 10 meter-class of telescopes such as GTC are yielding,” the researcher concludes

    See the full article here.

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

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  • richardmitnick 3:34 pm on October 30, 2014 Permalink | Reply
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    From Hubble: “Hubble Sees ‘Ghost Light’ From Dead Galaxies” 

    NASA Hubble Telescope

    Hubble

    October 30, 2014
    Ray Villard
    Space Telescope Science Institute, Baltimore

    NASA’s Hubble Space Telescope has picked up the faint, ghostly glow of stars ejected from ancient galaxies that were gravitationally ripped apart several billion years ago. The mayhem happened 4 billion light-years away, inside an immense collection of nearly 500 galaxies nicknamed “Pandora’s Cluster,” also known as Abell 2744.

    The scattered stars are no longer bound to any one galaxy, and drift freely between galaxies in the cluster. By observing the light from the orphaned stars, Hubble astronomers have assembled forensic evidence that suggests as many as six galaxies were torn to pieces inside the cluster over a stretch of 6 billion years.

    a2744
    Massive galaxy cluster Abell 2744, nicknamed Pandora’s Cluster, takes on a ghostly look where total starlight has been artificially colored blue in this Hubble view.
    Image Credit: NASA/ESA/IAC/HFF Team, STScI

    Computer modeling of the gravitational dynamics among galaxies in a cluster suggests that galaxies as big as our Milky Way Galaxy are the likely candidates as the source of the stars. The doomed galaxies would have been pulled apart like taffy if they plunged through the center of a galaxy cluster where gravitational tidal forces are strongest. Astronomers have long hypothesized that the light from scattered stars should be detectable after such galaxies are disassembled. However, the predicted “intracluster” glow of stars is very faint and was therefore a challenge to identify.

    “The Hubble data revealing the ghost light are important steps forward in understanding the evolution of galaxy clusters,” said Ignacio Trujillo of The Instituto de Astrofísica de Canarias (IAC), Santa Cruz de Tenerife, Spain. “It is also amazingly beautiful in that we found the telltale glow by utilizing Hubble’s unique capabilities.”

    The team estimates that the combined light of about 200 billion outcast stars contributes approximately 10 percent of the cluster’s brightness.

    “The results are in good agreement with what has been predicted to happen inside massive galaxy clusters,” said Mireia Montes of the IAC, lead author of the paper published in the Oct. 1 issue of the Astrophysical Journal.

    Because these extremely faint stars are brightest at near-infrared wavelengths of light, the team emphasized that this type of observation could only be accomplished with Hubble’s infrared sensitivity to extraordinarily dim light.

    Hubble measurements determined that the phantom stars are rich in heavier elements like oxygen, carbon, and nitrogen. This means the scattered stars must be second or third-generation stars enriched with the elements forged in the hearts of the universe’s first-generation stars. Spiral galaxies – like the ones believed to be torn apart — can sustain ongoing star formation that creates chemically-enriched stars.

    Weighing more than 4 trillion solar masses, Abell 2744 is a target in the Frontier Fields program. This ambitious three-year effort teams Hubble and NASA’s other Great Observatories to look at select massive galaxy clusters to help astronomers probe the remote universe. Galaxy clusters are so massive that their gravity deflects light passing through them, magnifying, brightening, and distorting light in a phenomenon called gravitational lensing. Astronomers exploit this property of space to use the clusters as a zoom lens to magnify the images of far-more-distant galaxies that otherwise would be too faint to be seen.

    Montes’ team used the Hubble data to probe the environment of the foreground cluster itself. There are five other Frontier Fields clusters in the program, and the team plans to look for the eerie “ghost light” in these clusters, too.

    See the full article here.

    Another Hubble view of Abell 2744

    a2744a
    Description Abell 2744, nicknamed Pandora’s Cluster. The galaxies in the cluster make up less than five percent of its mass. The gas (around 20 percent) is so hot that it shines only in X-rays (coloured red in this image). The distribution of invisible dark matter (making up around 75 percent of the cluster’s mass) is coloured here in blue.
    Date 22 June 2011

    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 12:12 pm on October 30, 2014 Permalink | Reply
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    From FNAL- “Frontier Science Result: CDF A charming result” 


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

    Thursday, Oct. 30, 2014
    Diego Tonelli and Andy Beretvas

    Physicists gave funny names to the heavy quark cousins of those that make up ordinary matter: charm, strange, bottom, top. The Standard Model predicts that the laws governing the decays of strange, charm and bottom quarks differ if particles are replaced with antiparticles and observed in a mirror. This difference, CP violation in particle physics lingo, has been established for strange and bottom quarks. But for charm quarks the differences are so tiny that no one has observed them so far. Observing differences larger than predictions could provide much sought-after indications of new phenomena.

    sm
    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    A team of CDF scientists searched for these tiny differences by analyzing millions of decays of particles decaying into pairs of charged kaons and pions, sifting through roughly a thousand trillion proton-antiproton collisions from the full CDF Run II data set. They studied CP violation by looking at whether the difference between the numbers of charm and anticharm decays occurring in each chunk of decay time varies with decay time itself.

    The results have a tiny uncertainty (two parts per thousand) but do not show any evidence for CP violation, as shown in the upper figure. The small residual decay asymmetry, which is constant in decay time, is due to the asymmetric layout of the detector. The combined result of charm decays into a pair of kaons and a pair of pions is the CP asymmetry parameter AΓ , which is equal to -0.12 ± 0.12 percent. The results are consistent with the current best determinations. Combined with them, they will improve the exclusion constraints on the presence of new phenomena in nature.

    graph
    These plots show the effective lifetime asymmetries as function of decay time for D →K+K- (top) and D → π+π- (bottom) samples. Results of the fits not allowing for (dotted red line) and allowing for (solid blue line) CP violation are overlaid.

    See the full article here.

    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.

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  • richardmitnick 4:34 am on October 30, 2014 Permalink | Reply
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    From astrobio.net: “Planetary Atmospheres a Key to Assessing Possibilities for Life” 

    Astrobiology Magazine

    Astrobiology Magazine

    Oct 30, 2014
    No Writer Credit

    A planetary atmosphere is a delicate thing. On Earth, we are familiar with the ozone hole — a tear in our upper atmosphere caused by human-created chemicals that thin away the ozone. Threats to an atmosphere, however, can also come from natural causes.

    ear
    Earth’s atmosphere likely changed from a helium-heavy one to the nitrogen and oxygen mix we see today. Credit: NASA

    If a big enough asteroid smacks into a planet, it can strip the atmosphere away. Radiation from a star can also make an atmosphere balloon, causing its lighter elements to escape into space.

    Understanding how permanent an atmosphere is, where it came from, and most importantly what it is made of are key to understanding if a planet outside our solar system is habitable for life. Our instruments aren’t yet sophisticated enough to look at atmospheres surrounding Earth-sized planets, but astronomers are starting to gather data on larger worlds to do comparative studies.

    One such example was recently accepted in the journal Astrophysical Journal and is available now in a preprint version on Arxiv. The astronomers created models of planetary formation and then simulated atmospheric stripping, the process where a young star’s radiation can push lighter elements out into space.

    Next, the team compared their findings to data gathered from NASA’s planet-hunting Kepler Space Telescope. The researchers predict that the atmospheric mass of the planets Kepler found is, in some cases, far greater than the thin veneer of air covering Earth.

    NASA Kepler Telescope
    NASA/Kepler

    Co-author Christoph Mordasini, who studies planet and star formation at the Max Planck Institute for Astronomy in Heidelberg, Germany, cautioned there is likely an observational bias with the Kepler data.

    “Kepler systems are so compact, with the planets closer to their star than in our solar system,” said Mordasini.

    Astronomers are still trying to understand why.

    “Maybe some of these objects formed early in their system’s history, in the presence of lots of gas and dust,” he said. “This would have made their atmospheres relatively massive compared to Earth. Our planet probably only formed when the gas was already gone, so it could not form a similar atmosphere.”

    Blowing gas away

    Planetary systems come to be in a cloud of gas and dust, the theory goes. If enough mass gathers in a part of the cloud, that section collapses and creates a star surrounded by a thin disk. When the star ignites, its radiative force will gradually clear the area around it of any debris.

    Over just a few million years, the hydrogen and helium in the disk surrounding the star partially spirals onto the star, while the rest gets pushed farther and farther out into space. Proto-Earth likely had a hydrogen-rich atmosphere at this stage, but over time (with processes such as vulcanism, comet impacts, and biological activity) its atmosphere gradually changed to the nitrogen and oxygen composition we see today.

    Kepler’s data has showed other differences from our own solar system. In our own solar system, there is a vast size difference between Earth and the next-biggest planet, Neptune, which has a radius almost four times that of Earth’s. This means there’s a big dividing line when it comes to size between terrestrial planets and gas giants in our solar system.

    venus
    This global view of the surface of Venus is centered at 180 degrees east longitude. Magellan synthetic aperture radar mosaics from the first cycle of Magellan mapping are mapped onto a computer-simulated globe to create this image. Data gaps are filled with Pioneer Venus Orbiter data, or a constant mid-range value. Simulated color is used to enhance small-scale structure. The simulated hues are based on color images recorded by the Soviet Venera 13 and 14 spacecraft. Credit: NASA/JPL

    In Kepler surveys (as well as surveys from other planet-hunting telescopes), scientists have found more of a gradient. There are other planetary systems out there with planets in between Earth’s and Neptune’s sizes, which are sometimes called “super-Earths” or “mini-Neptunes.” Whether planets of this size are habitable is up for debate.

    “The gap between the Earth’s and Uranus’ or Neptune’s size, and also in their composition, doesn’t exist in extrasolar planets. So, what we see in the Solar System is not the rule,” Mordasini said.

    The planets that Kepler has picked up, however, tend to be massive and closer to their star, and are therefore easier to detect. They pass more frequently across the face of their parent star, making them more easily spotted from Earth.

    The size implies that they managed to grab their disk’s primordial hydrogen and helium atmosphere before it got blown away. Hydrogen and helium are light elements, so a star’s radiation would puff up the hydrogen and helium atmosphere far more than what we see on Earth, with its heavier elements.

    What does this mean? The team predicts that in some cases, when astronomers measure the radius of a planet, that measurement also includes a bulky atmosphere. In other words, the planet underneath could be a lot smaller than what Kepler’s measurements could indicate.

    This process assumes that the planet has an iron core and silica mantle, just like the Earth, but orbits its parent star about 10 times closer than we do ours. If the atmosphere is more massive — even 1 percent of the planet’s mass is many thousands of times more massive than Earth’s — it creates more pressure on the surface.

    “It depends, but you can imagine this pressure is comparable to the deepest parts of the Earth’s ocean. Additionally, these atmospheres can be isolating and insulating for heat, so it’s also very hot on the surface,” Mordasini said.

    High temperatures on Earth are known to destroy amino acids, the building blocks of carbon-based life.

    Delicate atmosphere

    The atmosphere may be more massive, but it is also delicate. It wouldn’t take too much of a push to send hydrogen, the lightest element, away from the planet and into space.

    k69
    A habitable zone planet, Kepler-69c, in an artist’s impression. The world is probably an inhospitable “super-Venus,” but then again, it might be habitable, depending on the character of its atmosphere. Credit: NASA Ames/JPL-Caltech

    Young stars like the Sun in its youth are especially active in x-rays and ultraviolet radiation. When these forms of light hit a planetary atmosphere, they tend to heat it up. Since heating expands gases, the atmosphere grows. An atmosphere that flows beyond certain heights can get so high that part of it gets “unbounded” from the planet’s gravity and escapes into space.

    In our own solar system, for example, Mars likely lost its hydrogen to space over time while a heavier kind of hydrogen (called deuterium) remained behind. A new NASA orbiting spacecraft called Mars Atmosphere and Volatile Evolution (MAVEN) has just arrived at the Red Planet to study more about atmospheric escape today and researchers will to try to extrapolate that knowledge to space.

    NASA MAVEN
    NASA/MAVEN

    By contrast, the planet Venus is an example of having an exceptionally persistent atmosphere. The mostly carbon dioxide atmosphere is so thick today that the planet is completely shrouded in clouds. Underneath the atmosphere is a hellish environment, one in which the spacecraft that have made it there have only survived a few minutes in the 864 º Fahrenheit (462 º Celsius) heat on the surface. It is widely presumed that atmospheres like that of Venus would be too hot for carbon-based life.

    Why Venus, Mars and Earth are so different in their atmospheric composition and history is among the questions puzzling astronomers today. Understanding atmospheric escape on each of these worlds will be helpful, scientists say.

    “How strong atmospheric escape is depends on fundamental properties such as mass or planetary orbit,” Mordasini said. “We found out for giant planets like Jupiter, the operation is typically not as strong.”

    Future work of the team includes considering atmospheres that are not made of hydrogen or helium, which could bring researchers a step closer to understanding how different types of elements work on planets. Eventually, this could feed into models predicting habitability.

    See the full article here.

    NASA

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  • richardmitnick 5:29 pm on October 29, 2014 Permalink | Reply
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    From SKA: “Australian Square Kilometre Array telescope takes shape in WA outback” 

    SKA Square Kilometer Array

    SKA

    13 Oct 2014
    Gian De Poloni

    A project to build one of the world’s most powerful radio astronomy telescopes is taking shape in Western Australia’s outback.

    The $160 million Australian Square Kilometre Array Pathfinder [ASKAP] is being built in a radio quiet area of WA’s Murchison region, about a four-hour drive from the port city of Geraldton.

    three
    Photo: Three ASKAP telescopes are trained towards the sky east of Geraldton. (Alex Cherney)

    The project has seen the installation of 36 huge antenna dishes on Boolardy Station, which will eventually work together to survey large areas of sky to help scientists understand how galaxies have formed and evolved.

    CSIRO scientist Lisa Harvey-Smith said although only six of the dishes were active, the images that had been taken so far were remarkable.

    “The latest picture we’ve taken has almost 2000 galaxies in it, which is incredible,” she said.

    “It’s kind of a wide field image of the sky.

    “Once we’ve got 36 telescopes, we’ll be able to do a huge survey of the entire night’s sky and see millions of new galaxies, black holes and things in the very distant universe that no one’s ever seen before.”

    She said the question of what exactly the telescope will be able to see in distant space was a complete mystery.

    “The discovery potential of this telescope is quite amazing,” she said.

    “Even now, we’ve been able to look at galaxies that are actually older than our Earth – which is a pretty incredible thing – and look into the distant universe to search for galaxies that were actually around billions of years ago and may not exist anymore.”

    Dr Harvey-Smith said the giant dishes were picking up radio waves being emitted from objects in space.

    “Our eyes can’t see radio waves, so the data that we get is just boring ones and zeros, but we actually use clever computer algorithms and a super computer that’s based in Perth to make the images into real optical type images that we can see,” she said.

    Telescope will view area 200 time size of moon

    Project director Antony Schinckel said images produced so far were stunning.

    “The thing about ASKAP is it’s a completely new type of telescope – it’s never been built before – so a lot of this very early work is simply understanding exactly how to use it,” he said.

    “Many of our staff said ‘look, it’s not worth trying to do much with just the six dishes because we won’t be able to see much’, but they’ve been completely shown to be wrong.

    “Trying to predict ahead to what we’re going to see with 36 at the full capability is really hard but we’ll be able to very quickly map really big areas of the sky and by really big, I mean in a single snapshot we’ll be able to see an area around about 200 times the size of the full moon.

    “There are still huge holes in our knowledge of how our universe evolved, where galaxies come from, how planets form and we expect ASKAP will be able to really help us answer a lot of that.”

    Dr Schinckel estimated it would cost about $10 million a year to keep the project going.

    “We’ve had good support from the Government over the last few years and we believe the Government does see the positive impacts of these sorts of projects,” he said.

    “There’s the pure science side, there’s the very tight international collaboration aspect, there’s the technology spin off, there’s training of engineers and scientists who may or may not stay on in astronomy but may go on to work in other fields.”

    ASKAP is viewed as a precursor to the future $1.9 billion Square Kilometre Array, which will be built in both the Murchison and South Africa in 2018, with input in design and funding coming from 11 countries.

    The SKA is expected to be the largest and most capable radio telescope.

    what
    Photo: This wide shot image taken from the ASKAP telescope over 12 hours shows distant galaxies. (Supplied: CSIRO)

    telescope
    ASKAP telescope image Photo: This wide shot image taken from the ASKAP telescope over 12 hours shows distant galaxies. (Supplied: CSIRO)

    Murchison ideal location for project

    Dr Harvey-Smith said the isolation of the Murchison region made it the perfect place for the project.

    “If you could imagine trying to listen for a mouse under your floorboards hearing tiny scratching noises, you don’t want to be playing the radio very loudly in the background,” she said.

    “It’s the same type of thing with the radio telescopes.

    “We’re looking for tiny, tiny signals incredibly week from galaxies billions of light years away.
    Under a brilliant night sky, ASKAP telescopes are pointed to the night stars Photo: Raw data from the ASKAP telescopes totals about 100 terabytes per second. (Alex Cherney)

    “They’re so weak we have to amplify them millions of times with specialist electronic equipment.”

    Dr Schinckel said the communications infrastructure in place to support the telescope was unfathomable.

    “The raw data rate we get from the telescopes is about 100 terabytes per second,” he said.

    “To put that in context, that’s about the entire traffic of the internet all around the world in one second.

    “Luckily the super computers we have on site can very quickly reduce the data back to a more manageable volume of around about 10 gigabytes per second.

    “The sheer volume of that and the speed of which that raw data comes in is truly astounding.”

    Dr Harvey Smith said she could control the telescope from the comfort of her lounge room.

    “As one of the research scientists, I can access the telescope from Sydney – from my house, on my laptop,” she said.

    “We just send signals through the internet and tell the telescope what to do.

    “It’s pretty amazing that we can have a giant international scientific facility with very few people actually out there on the site.”

    It is hoped the entire network of dishes will be fully operational by March 2016.

    See the full article here.

    SKA Banner

    About SKA

    The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10 000 times the survey speed, of the best current-day telescopes. The SKA will be built in Southern Africa and in Australia. Thousands of receptors will extend to distances of 3 000 km from the central regions. The SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the Big Bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth. Construction of phase one of the SKA is scheduled to start in 2016. The SKA Organisation, with its headquarters at Jodrell Bank Observatory, near Manchester, UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.

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  • richardmitnick 4:52 pm on October 29, 2014 Permalink | Reply
    Tags: , , Basic Research, , , Redshift   

    From Frontier Fields: “Light Detectives: Using Color to Estimate Distance” 

    Frontier Fields
    Frontier Fields

    October 28, 2014
    Dr. Brandon Lawton

    Distances are notoriously difficult to measure in astronomy. Astronomers use many methods for estimating distances, but the farther away an object is, the more uncertain the results. Cosmological distances, distances on the largest scales of our universe, are the most difficult to estimate. To measure the distances to the farthest galaxies, those gravitationally lensed by massive foreground galaxy clusters, astronomers really have their work cut out for them.

    If a massive stellar explosion, known as a supernova, happens to go off in a galaxy and we catch it, then we can use the “standard candle” method of computing the distance to the galaxy. Supernovae are expected to be discovered in the Frontier Fields, but not at the numbers that will help us find distances to most of the galaxies in the images. Without these standard candles, astronomers must use other means to estimate distances.

    A Spectrum is Worth a Thousand Pictures

    One of the more accurate methods for measuring the distance to a distant galaxy involves obtaining a spectrum of the galaxy. Getting a galaxy’s spectrum basically means taking the light from that galaxy and breaking it up into its component colors, much like a prism breaks up white light into the rainbow of visible colors. By comparing the brightness of light at each component color, a spectrum can give us a wealth of information. This can include detailed information about a galaxy’s composition, temperature, and how fast it is moving relative to us. Because the universe is expanding, we observe most galaxies, and all distant galaxies, to be moving away from us.

    When looking at a distant galaxy’s spectrum, the expansion of the universe causes the component colors in the spectrum to be stretched to longer wavelengths. For visible light, red has the longest wavelengths, which leads to the term ‘redshift’. This cosmological redshift can be accurately measured from a spectrum. Astronomers then use mathematical models of the expansion rate of our universe to convert the measured redshift into an estimate of distance. Larger values of redshift correspond to larger distances.

    This video, developed by the Office of Public Outreach at the Space Telescope Science Institute, gives a demonstration of how light is redshifted as it travels through the expanding universe. Here, the lightbulb stands in place of a galaxy. As the universe expands, it stretches the light traveling through the universe, increasing the light’s wavelength. As the wavelength increases, it becomes more red. Light traveling longer distances through the universe will be stretched/reddened more than light traveling short distances. This is why astronomers use instruments sensitive to redder light, including infrared light, when they attempt to observe the light from very distant galaxies. Watch this video on Youtube.

    Larger redshifts not only correspond to larger distances, but they also correspond to earlier times in our universe’s history. This is because light takes time to travel to us from these distant galaxies. The more distant the galaxy, the longer the light has been traveling before we intercept it with sensitive telescopes, like Hubble.

    Assuming typical contemporary mathematical models, the universe is about 13.8 billion years old. Galaxies at a redshift of 1 are seen as they existed when the universe was about 6 billion years old. Galaxies at a redshift of 3 are seen as they existed when the universe was about 2 billion years old. Galaxies at a redshift of 6 are seen as they existed when the universe was about 1 billion years old. Galaxies at a redshift of 10 are seen as they existed when the universe was only about 500 million years old.

    It is notoriously difficult to obtain a spectrum of a very distant galaxy. They are very faint, and an accurate spectrum relies on obtaining a lot of light. One is, after all, taking what little light you get and breaking it up further into the component colors, meaning that you start with little light and get out even less light at each component color. Getting enough light to take an accurate spectrum of a distant galaxy requires very lengthy observations with sensitive telescopes. This is not always feasible.

    Redshifts measured via spectra are called spectroscopic redshifts. Many of the nearer galaxies in Abell 2744 have measured spectroscopic redshifts. There will likely be many follow-up observations from ground- and space-based observatories to obtain spectra of many of the fainter and more distant galaxies in the Frontier Fields. So stay tuned!
    I Can’t Obtain a Spectrum! What to do?

    If you do not have a spectrum, are there other ways to estimate the redshift and distance to a galaxy? Yes! Just take a look at the galaxy’s colors.

    All Hubble images are taken with filters. Blue filters allow Hubble’s instruments to capture only blue light, red filters allow Hubble’s instruments to capture only red light, and so on. By comparing a galaxy’s brightnesses in these different colors, astronomers can estimate the distance to the galaxy. The redder the color, the more likely the galaxy is to be redshifted, and thus, farther away.

    This technique of using color to estimate redshift is called photometric redshift. The following two primary methods are used for estimating a photometric redshift:

    compare the colors of your high-redshift galaxy candidate to a set of typical galaxy color templates at various redshifts, or
    compare the colors of your high-redshift galaxy candidate to a set of galaxies with measured spectroscopic redshifts and, utilizing specialized software, compute the most likely redshift for your galaxy.

    In the first case, the photometric redshift comes from the best match between the observed high-redshift candidate colors and the colors of the template galaxies. The template galaxy colors stem from observations of galaxies that tend to be relatively close but are then mathematically reddened over a range of redshift values.

    In the second case, astronomers use a set of observed galaxies whose redshifts have been measured spectroscopically, as explained in the prior section. This set contains galaxies at various redshifts. They then use machine-learning algorithms to compare the colors of this set of galaxies with the colors of the target high-redshift galaxy candidate. The software selects the most likely redshift.

    Whichever method is used, astronomers are careful to give confidence levels in their calculations. For the computation of photometric redshift, there is typically an uncertainty of around a few percent for high-quality data. In addition, there is the lingering issue of whether the high-redshift galaxy candidate is truly redshifted, or if it is a nearer galaxy that is intrinsically redder. It is not uncommon to read results where astronomers find a galaxy with a probable high photometric redshift and a less probable low photometric redshift, or vice versa.

    shif
    Credit: Adapted from Adi Zitrin, et al., 2014. Shown is a high-redshift galaxy candidate in Hubble’s observations of Abel 2744, discovered using filters. Dark regions represent light in these images. Notice how the galaxy drops out of the image in the bluest filters. This is a hint that the galaxy may be significantly redshifted.

    Many of the first results for the Frontier Fields utilize photometric redshifts. In the absence of spectra, photometric redshifts are the next best thing to obtaining estimates of distances for large samples of galaxies. They are readily computed from the current Frontier Fields data.

    See the full article, with video, here.

    Frontier Fields draws on the power of massive clusters of galaxies to unleash the full potential of the Hubble Space Telescope. The gravity of these clusters warps and magnifies the faint light of the distant galaxies behind them. Hubble captures the boosted light, revealing the farthest galaxies humanity has ever encountered, and giving us a glimpse of the cosmos to be unveiled by the James Webb Space Telescope.

    NASA Hubble Telescope
    Hubble
    NASA James Webb Telescope
    Webb
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  • richardmitnick 4:31 pm on October 29, 2014 Permalink | Reply
    Tags: , Basic Research, ,   

    From Chandra: “NASA’S Chandra Observatory Identifies Impact of Cosmic Chaos on Star Birth” 

    NASA Chandra

    October 27, 2014

    Felicia Chou
    Headquarters, Washington
    202-358-0257
    felicia.chou@nasa.gov

    Janet Anderson
    Marshall Space Flight Center, Huntsville, Ala.
    256-544-6162
    janet.l.anderson@nasa.gov

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

    The same phenomenon that causes a bumpy airplane ride, turbulence, may be the solution to a long-standing mystery about stars’ birth, or the absence of it, according to a new study using data from NASA’s Chandra X-ray Observatory.

    Galaxy clusters are the largest objects in the universe, held together by gravity. These behemoths contain hundreds or thousands of individual galaxies that are immersed in gas with temperatures of millions of degrees.

    This hot gas, which is the heftiest component of the galaxy clusters aside from unseen dark matter, glows brightly in X-ray light detected by Chandra. Over time, the gas in the centers of these clusters should cool enough that stars form at prodigious rates. However, this is not what astronomers have observed in many galaxy clusters.

    “We knew that somehow the gas in clusters is being heated to prevent it cooling and forming stars. The question was exactly how,” said Irina Zhuravleva of Stanford University in Palo Alto, California, who led the study that appears in the latest online issue of the journal Nature. “We think we may have found evidence that the heat is channeled from turbulent motions, which we identify from signatures recorded in X-ray images.”

    Prior studies show supermassive black holes, centered in large galaxies in the middle of galaxy clusters, pump vast quantities of energy around them in powerful jets of energetic particles that create cavities in the hot gas. Chandra, and other X-ray telescopes, have detected these giant cavities before.

    The latest research by Zhuravleva and her colleagues provides new insight into how energy can be transferred from these cavities to the surrounding gas. The interaction of the cavities with the gas may be generating turbulence, or chaotic motion, which then disperses to keep the gas hot for billions of years.

    “Any gas motions from the turbulence will eventually decay, releasing their energy to the gas,” said co-author Eugene Churazov of the Max Planck Institute for Astrophysics in Munich, Germany. “But the gas won’t cool if turbulence is strong enough and generated often enough.”

    The evidence for turbulence comes from Chandra data on two enormous galaxy clusters named Perseus and Virgo. By analyzing extended observation data of each cluster, the team was able to measure fluctuations in the density of the gas. This information allowed them to estimate the amount of turbulence in the gas.

    tgwo
    Chandra observations of the Perseus and Virgo galaxy clusters suggest turbulence may be preventing hot gas there from cooling, addressing a long-standing question of galaxy clusters do not form large numbers of stars. Image Credit: NASA/CXC/Stanford/I. Zhuravleva et al

    “Our work gives us an estimate of how much turbulence is generated in these clusters,” said Alexander Schekochihin of the University of Oxford in the United Kingdom. “From what we’ve determined so far, there’s enough turbulence to balance the cooling of the gas.

    These results support the “feedback” model involving supermassive black holes in the centers of galaxy clusters. Gas cools and falls toward the black hole at an accelerating rate, causing the black hole to increase the output of its jets, which produce cavities and drive the turbulence in the gas. This turbulence eventually dissipates and heats the gas.

    While a merger between two galaxy clusters may also produce turbulence, the researchers think that outbursts from supermassive black holes are the main source of this cosmic commotion in the dense centers of many clusters.

    An interactive image, podcast, and video about these findings are available at:

    http://chandra.si.edu

    For more Chandra images, multimedia and related materials, visit:

    http://www.nasa.gov/chandra

    See the full article here.

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

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