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  • richardmitnick 9:42 am on October 24, 2014 Permalink | Reply
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    From SPACE.com: “Einstein’s Gravity Waves Could Be Found with New Method” 

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    October 24, 2014
    Charles Q. Choi

    Gravitational waves, invisible ripples in the fabric of space and time, might be detected by looking for the brightening of stars, researchers say.

    gw
    This illustration depicts the gravitational waves generated by two black holes orbiting each other.
    Credit: NASA

    These mysterious ripples were first proposed by Albert Einstein as part of his theory of general relativity. The waves’ size depends on the mass of the objects creating them.

    “Gravitational waves are emitted by accelerating masses,” said lead study author Barry McKernan, an astrophysicist at the American Museum of Natural History in New York. Really big waves are emitted by really big masses, such as systems containing black holes merging with each other.

    Scientists have still not made direct observations of gravitational waves, although researchers continue to endeavor to detect them using experiments involving lasers on the ground and in space. The waves interact very weakly with matter, which partly explains why seeing these ripples in spacetime is difficult.

    Now, McKernan and his colleagues suggest that gravitational waves could have more of an effect on matter than previously thought, with their influence potentially brightening stars.

    “It’s neat that nearly 100 years after Einstein proposed his theory of general relativity, there are still interesting surprises it can turn up,” McKernan told Space.com. “We’re brought up as astronomers thinking the interaction between matter and gravitational waves is very weak, essentially negligible, and that turns out not to be true.”

    The researchers suggest that stars that vibrate at the same frequency as gravitational waves passing through them can absorb a large amount of energy from the ripples.

    “You can imagine gravitational waves as sounds from a piano, and stars as a vibrating violin string held near that piano,” McKernan said. “If the frequency of the sounds matches the frequency of the violin string, the string can resonate with the sound.” If a star gets pumped up with large amounts of energy from gravitational waves in this way, “the star can puff up and look brighter than it normally would,” McKernan said.

    One challenge is determining whether any star brightening astronomers detect is from gravitational waves or some other factor. The researchers suggest the key to spotting the effects of gravitational waves involves looking at large groups of stars.

    “When a population of stars is near a system of merging black holes and is getting pounded by gravitational waves, we think that the more massive stars will light up first,” McKernan said. “It’s like playing keys on a piano and starting with low pitches.” As the black holes get closer together, the frequency of the gravitational waves they generate will increase, “and we’d expect to see brightening of smaller stars,” he added. “If we see a population of stars where the smaller stars are brightening after the bigger stars in a collective way, that might be a sign of gravitational waves.”

    This research also suggests a different way to indirectly detect gravitational waves. If scientists develop working gravitational wave detectors on Earth or in space, when a star passes in front of powerful sources of gravitational waves such as merging black holes, the detector may see a drop in the intensity of those waves. This will happen if the eclipsing star is vibrating at the right frequency.

    “You usually think of stars as being eclipsed by something, not the other way around,” McKernan said in a statement.

    McKernan and his colleagues Saavik Ford, Bence Kocsis and Zoltan Haiman detailed their findings online Sept. 22 in the journal Monthly Notices of the Royal Astronomical Society: Letters.

    See the full article here.

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  • richardmitnick 8:17 am on October 24, 2014 Permalink | Reply
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    From SPACE.com:”Saturn’s ‘Death Star’ Moon Mimas Is Weird Inside” 

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    October 16, 2014
    Kelly Dickerson

    There’s something strange going on below the surface of Saturn’s Death Star-looking moon Mimas, a new study suggests.

    star

    Mimas’ rotation and its orbit around Saturn make the moon look like it’s rocking and back forth and oscillating similar to the way a pendulum swings. The rocking motion is called libration, and it’s commonly observed in moons that are influenced by the gravity from neighboring planets. However, using images of the moon captured by the Cassini spacecraft, Radwan Tajeddine, a research associate at Cornell University, discovered that the satellite’s libration was much more exaggerated in one spot than predicted. He expects it must be caused by the moon’s weird interior.

    NASA Cassini Spacecraft
    NASA/ Cassini

    “We’re very excited about this measurement because it may indicate much about the satellite’s insides,” Tajeddine said in a statement. “Nature is essentially allowing us to do the same thing that a child does when she shakes a wrapped gift in hopes of figuring out what’s hidden inside.”

    Feel the libration

    Astronomers have long been using the rotation and orbit of celestial bodies to guess what their interiors might be like. Most of the rocking is explained by the interacting forces from Mimas’ rotation and orbit, but one libration was much larger than expected.

    Tajeddine and the team tested five different models of what Mimas might look like below the surface to see which one could explain the exaggerated rocking. They quickly ruled out the possibility that Mimas has a uniform interior, an interior with two different layers or an abnormal mass under the moon’s 88-mile-long (142 kilometers) crater that makes it look like the Death Star from the “Star Wars” franchise.

    However, the last two models could both explain Mimas’ extreme libration. One idea is that the moon has an elongated, oval-shaped core. This elongation might have happened as the moon formed under the push and pull of Saturn’s rings. The teeter tottering could also come from a subsurface ocean, similar to the one on Jupiter’s moon Europa.

    While it’s still a possibility, Tajeddine thinks the subsurface ocean is an unlikely explanation. Astronomers have not observed any evidence of liquid water on Mimas, unlike some of Saturn’s other moons. The heat radiating from the core escapes through the moon’s ice-covered shell and would cause any subsurface ocean that existed to quickly freeze.

    3D Mimas map

    Mimas is the smallest and closest of Saturn’s main eight moons. Its giant crater covers almost one-third of the moon’s icy surface.

    For the past 10 years,the Cassini space probe has been collecting data on Mimas, Saturn and the ringed wonder’s other natural satellites. The Imaging Science Subsystem (ISS) onboard Cassini is a two-camera system that captures ultraviolet and infrared images of Saturn and its moons.

    Tajeddine and a team of researchers sifted through dozens of images captured by ISS and created a 3D map of the moon from the photos to study how Mimas spins and orbits Saturn.

    The new research was published this week in the journal Science.

    See the full article here.

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  • richardmitnick 9:33 am on October 17, 2014 Permalink | Reply
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    From SPACE.com: “NASA Probe Finds Nanoflares and Plasma ‘Bombs’ on Sun” 

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    October 16, 2014
    Nola Taylor Redd

    The first results from a new NASA sun-studying spacecraft are in, and they reveal a complex and intriguing picture of Earth’s star.

    NASA’s Interface Region Imaging Spectrograph probe (IRIS) has observed ‘bombs’ of plasma on the sun, nanoflares that rapidly accelerate particles, and powerful jets that may drive the solar wind, among other phenomena, five new studies report.

    iris
    The completed IRIS observatory with solar arrays destroyed prior to launch. Credit: NASA

    While spacecraft can enter planetary atmospheres, they cannot fly through the outer atmosphere of the sun, where temperatures reach 3.5 million degrees Fahrenheit (2 million degrees Celsius). Probes like IRIS instead must study the star from a safe distance. Unlike previous instruments, IRIS can take far more detailed observations of the sun, capturing observations of regions only about 150 miles (240 kilometers) wide on a time scale of just a few seconds.

    “The combination of enhanced spatial and spectral resolution, [which are] both three to four times better than previous instruments, allows a much closer look [at the sun's atmosphere],” Hardi Peter of the Max Planck Institute for Solar System Research in Germany told Space.com by email. Peter was the lead author on a study of hot plasma ‘bombs’ on the sun.

    Nanoflare acceleration

    The surface of the sun, or photosphere, is the region visible to human eyes. Above the photosphere lie the hotter chromosphere and transition regions, which emit ultraviolet light that can only be observed from space. This is because Earth’s atmosphere absorbs most of this radiation before it reaches land-based instruments. The outer part of the solar atmosphere is called the corona.

    While much of the sun’s energy is generated in its core through hydrogen fusion, temperatures rise in the exterior layers moving out farther from the heat source. This means that something is powering that outer region, and scientists think the magnetic fields generated by the churning solar plasma provide at least part of the answer.

    In emerging active regions, magnetic fields rise through the surface into the upper atmosphere, like a string pulled upward. When the energy carried by the field lines becomes too great, they snap, disconnecting from one another and reconnecting with other broken field lines in a process known as magnetic reconnection.

    Paola Testa, of the Harvard-Smithsonian Center for Astrophysics, led a team that used IRIS to study the footprints of these loops, where he found that the intensity changed over a span of 20 to 60 seconds. Investigating possible causes, Testa determined that the variations were consistent with simulations of electrons generated from coronal nanoflares.

    “Nanoflares are short heating events releasing amounts of energy about a billion times smaller than large flares,” Testa said.

    fl
    Ultraviolet image of an active region on the sun, showing plasma at temperatures of 140,000 degrees. This image was captured by NASA’s IRIS spacecraft on Dec. 6, 2013.
    Credit: IRIS: LMSAL, NASA. Courtesy Bart De Pontieu, Lockheed Martin Solar & Astrophysics Laboratory

    Although smaller than their larger cousins, nanoflares occur more frequently, likely due to magnetic reconnection. Energy released during magnetic reconnection accelerates some particles to high energies, where they are emitted as radio waves and the highest energy X-rays. Scientists have observed these signals in medium and large flares, but for nanoflares, the rapidly moving electrons are too faint to detect directly using current instrumentation.

    “That is why our observations in the ultraviolet are particularly interesting,” Testa said. “They provide an alternative way to study these accelerated particles, although not directly observing them.”

    Hot bombs in cool regions

    In the cooler photosphere of the sun, where temperatures reach approximately 10,000 degrees F (5,500 degrees C), the magnetic fields convert a huge amount of energy from the magnetic energy stored in the field into thermal energy, heating the plasma. According to Peter, the amount of energy released would be enough to provide electric power to Germany for 8,000 years. The change creates a pocket of gas heated up to 180,000 degrees F (100,000 degrees C) in the middle of the cooler surface region.

    These pockets, or “bombs,” eject plasma. Upward-moving material probably disperses into the hot corona, Peter said, while the downward-moving plasma is quickly cooled to reach the same material as the rest of the photosphere, blending back in to the surrounding material.

    Previously, scientists spotted no indications that energy-releasing events in the photosphere would result in the high temperature spikes in pockets within the photosphere. The energy output required to heat the dense gas was thought to be too high to be obtainable.

    “With these new results that show the existence of hot pockets in cool gas, we have to either revise the amount of energy that can be supplied deep in the photosphere, or we have to think of a clever yet unknown mechanism to heat the cool, dense gas rapidly to these high temperatures,” Peter said.

    Do the twist

    In addition to disconnecting and reconnecting, the magnetic fields on the sun also twist. As the twisting field lines move away from the surface at 19 to 62 miles (30 to 100 km) per second, the nearby transition regions brighten to temperatures of up to 144,000 degrees F (80,000 C), far above the chromosphere’s average temperature of 7,800 degrees F (4,000 degrees C).

    IRIS’s detailed study of the sun revealed that the twists are far more widespread than suggested by previous studies. These twists occur in every magnetic region, both quiet and active. Observations of twists were made at IRIS’s maximum resolution, but other unresolved small-scale motions in the observations seemed to indicate the presence of even smaller twists in the field lines.

    Although the current data does not allow the scientists to determine the twists’ cause, IRIS science lead and first author Bart De Pontieu, of Lockheed Martin Solar and Astrophysics Laboratory, said that the twisting is most likely a signature of the so-called Alfven waves. These “magnetic waves [are] not unlike the waves that are generated after plucking a guitar string,” he said. The source of these waves also remains unknown.

    Another potential source could be the strong convective, or “boiling,” motions at the sun’s surface.

    “Numerical simulations of the solar convection suggest that torsional [twisting] motions can be generated, kind of like when you drain a bathtub, and you see swirling motions as the water drains out,” De Pontieu said.

    Scientists have several hypotheses for how the solar atmosphere is heated, and De Pontieu said the new observations provide constraints on these theories.

    “In particular, they provide support for models in which Alfven waves do much of the heavy lifting in the solar atmosphere,” he said.

    sun
    In its first released image of the sun, IRIS captured a view of the solar atmosphere. Credit: NASA

    As the closest and brightest star, the sun has been studied throughout history. Based on indirect evidence from Skylab and other missions in the 1970s and 1980s, astronomer Uri Feldman, of the Naval Research Laboratory, proposed the existence of “unresolved fine structures” (UFS), an important solar atmospheric component in the transition region between the chromosphere and the corona. Using IRIS’s instruments, a team lead by Viggo Hansteen, of the University of Oslo in Norway, determined that a series of low-lying magnetic loops constitute these UFS, settling a decades-long debate regarding their existence.

    The loops of the magnetic field light up for short spans of time, perhaps a minute, when the plasma in the loops are heated, either due to magnetic reconnection or the dissipation of Alfven waves. During magnetic reconnection, plasma is accelerated to 2 to 3 times the speed of sound. Sometimes the loops form in isolation; other times they are concentrated in a nest of loops.

    The debate regarding the loops’ existence stemmed in part from questions about the plasma; scientists questioned whether or not all of the plasma in the transition region was thermally connected to the corona. The presence of the low-lying loops in the transition region confirms that plasma reaching temperatures of 180,000 degrees F (100,000 degrees C) are heated by from the loops rather than the corona.

    Although the loops themselves don’t heat the corona, Hansteen said that they are probably heated with the same mechanism, though with a different response due to their higher density.

    “It is likely that these differences will allow us to focus more clearly on the nature of the unknown heating events themselves,” Hansteen said.

    Powering the solar wind

    The solar wind drives particles and plasma from the sun through the solar system. When the particles collide with Earth’s magnetic field, they produce beautiful auroras, and have the potential to interfere with satellites and communication systems. But the source of the solar wind remains a mystery.

    The fast-moving solar wind travels hundreds of kilometers per second, carrying low-density materials. Previous instruments lacked the ability to study the small-scale regions thought to be responsible for the wind with the precision necessary to understand it.

    Scientists suspect that the solar wind originates from the bright network structures on the sun, appearing as bright lanes enclosing dark cells. These lanes flow outward from the sun, funneled by the magnetic structure, and eventually merge together into a single solar wind stream that flows steadily from the sun.

    A team lead by Hui Tian, of the Harvard-Smithsonian Center for Astrophysics, identified high-speed, intermittent jets in what scientists think is the solar wind source region, making these jets likely candidates for the initial stage of the solar wind. Rather than producing a steady outflow, the jets are sporadic, accelerating particles to speeds up of to 155 miles per second (250 km/s).

    “If these jets really are the nascent solar wind, then solar wind models must be updated to produce these intermittent, high-speed and small-scale outflows in the interface region,” Tian said.

    “If the answer is no, at least the impact of these jets on the still-not-observed nascent solar wind outflow should be carefully evaluated, because these jets are the most prominent dynamic feature in the believed solar wind source region,” he said.

    All five papers, along with a perspective piece by Louise Harra of the University College London, were published online today (Oct. 16) in the journal Science.

    See the full article, with video, here.

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  • richardmitnick 6:20 pm on October 13, 2014 Permalink | Reply
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    From SPACE.com: ” Why Space Exploration Must Continue (Op-Ed)” 

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    October 12, 2014
    Chris Arridge, Lancaster University

    Launched by the Soviet Union in 1957, Sputnik 1 became the world’s first artificial satellite – a “simple” battery-powered radio transmitter inside an aluminium shell about the size of a beach ball. This started a race to the stars, for both robotic space exploration and human spaceflight. This legacy continues today with our exploration of the solar system.

    spu
    Sputnik 1.

    Space exploration is a challenge to human ingenuity, and celebrations this week, under the guise of World Space Week, are an ode to it. Spacecraft have to be kept warm against the cold of space, but cool against the heat of the Sun – think of travelling from Antarctica to Africa without taking your coat off. They have to make electricity for themselves. They have to be able to work out what way they are facing. They need to be able to communicate with Earth – but even travelling at the speed of light it takes a radio signal about 40 minutes to get from Jupiter to Earth, so robotic spacecraft have to survive on their own.

    A simple reason why space exploration is valuable is that in developing spacecraft to explore distant worlds, we get better at building spacecraft for more practical purposes. Engineers and space scientists today have their work cut out to meet these challenges, but they follow in the footsteps of the early engineers and scientists who pioneer space exploration.
    From Sputnik to Mariner…

    Sputnik was originally envisaged as a scientific satellite but due to the available technology, and the developing race between the US and Soviet Union, it ended up being vastly simplified and didn’t carry any instruments. Nevertheless scientific work could still be done.

    The familiar beep-beep radio signal from Sputnik was distorted as it passed through Earth’s atmosphere. These distortions were used by scientists to study the atmosphere. These distortions affect GPS and satellite TV.

    Many other missions followed which did carry a scientific “payload”, Explorer 1 and Explorer 3 in 1958 discovered Earth’s “Van Allen” radiation belts (Sputnik 3 made similar, but incomplete measurements), Explorer 6 in 1959 returned the first pictures of Earth from orbit, and Explorer 10 in 1961 detected the first explosion from the Sun in interplanetary space, among many other firsts as human-kind learned how to explore space. Looking down on our planet from space has changed our perception of Earth and our place in the universe.

    The first spacecraft to visit another planet was Mariner 2, which flew past Venus on December 14 1962, having survived a near fatal anomaly in September 1962 that may have been the result of a meteoroid hitting the spacecraft. Other spacecrafts in the Mariner programme made spectacular firsts: Mariner 4 took the first close-up pictures of a planet, in this case Mars, from space and Mariner 9 was the first spacecraft to enter orbit around another planet.
    …then Venus to Saturn

    Mariner was very successful and the spacecraft design was used to develop other space missions, such as the twin Voyager spacecraft that are still operating 37 years later, the Magellan spacecraft that explored the surface of Venus with radar, and the Galileo spacecraft that surveyed Jupiter, its moons, and its space environment.

    NASA Voyager 2
    NASA/Voyager 2

    NASA Magellan
    NASA/Magellan

    NASA Galileo
    NASA/Galileo

    Voyager was unique in that it undertook a grand tour of Jupiter, Saturn, Uranus and Neptune, exploiting an alignment of the planets in the late 1970s that will not occur again until the mid-2100s. Voyager 1 has now entered interstellar space – the space between stars – at a distance of 20 billion km from Earth.

    The Cassini-Huygens mission is the first spacecraft to orbit Saturn and has made great discoveries in the Saturn system, such as lakes on Saturn’s largest moon Titan, giant geysers erupting from the south pole of the moon Enceladus, and potentially witnessing the birth of a new moon from debris in Saturn’s rings. Cassini is known as a Mariner Mark II spacecraft, continuing the 50-year Mariner legacy.

    NASA Cassini Spacecraft
    NASA/Cassini-Huygens

    Future of space exploration

    The European Space Agency’s JUICE mission combines all of the challenges that we started with. Aiming for launch in 2021, the spacecraft will fly by Venus on its way to Jupiter, then enter orbit around Jupiter, study its moons and then enter orbit around the largest moon, Ganymede. JUICE must survive near Venus where sunlight is twice as strong as at Earth, to Jupiter where sunlight is 30 times weaker.

    ESA JUICE
    ESA/JUICE

    More extreme challenges are found across our solar system. In July 2015, New Horizons will be the first spacecraft to fly past Pluto. Pluto is so far from Earth that data will come back from the spacecraft about 5,000 times slower than your home broadband, mimicking the early days of spaceflight where images of Mars from Mariner 4 took hours to trickle back to Earth.

    NASA New Horizons spacecraft
    NASA/New Horizons

    But it will provide a new window into a largely unknown alien world. What will we discover? What will we learn about the origins of the solar system? What will we learn about ourselves? Continued space exploration is the only way we can answer any of those questions.

    See the full article here.

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  • richardmitnick 2:18 pm on October 13, 2014 Permalink | Reply
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    From SPACE.com: ” Strange-Shaped Orbits of Giant ‘Warm Jupiter’ Planets Explained” 

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    Some huge alien worlds were probably pulled into their puzzling orbits by nearby planetary neighbors circling on a different plane, a new study reports.

    ttb
    Tau Bootis b, a “warm Jupiter”

    “Our results imply that there is a diversity of architectures for planetary systems, and that planetary systems aren’t always flat like the solar system,” said study lead author Rebekah Dawson of the University of California, Berkeley.

    Dawson and co-author Eugene Chiang, also of UC Berkeley, investigated “warm Jupiters,” enormous exoplanets that orbit much closer to their host stars than Saturn and Jupiter do in Earth’s solar system (but not as close as “hot Jupiters,” some of which can complete one lap around their parent stars in less than a day).

    Warm and hot Jupiters must have migrated inward significantly, astronomers say, because theory predicts that gas giants can only form relatively far from their stars — generally, beyond the “snow line,” where it’s cold enough for water and other volatile materials to condense into ice grains. But just what’s driving such dramatic planetary movement has been a matter of debate.

    Dawson and Chiang looked at six exoplanetary systems, each of which harbors a warm Jupiter with a large, more distantly orbiting planetary companion. For each system, they ran about 1,000 computer simulations that modeled the two planets’ orbital dynamics.

    The results suggest that when the two worlds’ orbits are inclined at a certain angle relative to each other — between 35 and 65 degrees — the companion can push the warm Jupiter closer and closer to its star.

    “In the type of evolution we studied, some warm Jupiters are in the midst of a slow evolution and may one day become hot Jupiters,” Dawson told Space.com via email. “There are other channels for forming hot Jupiters, and in the future, we plan to quantify what fraction of hot Jupiters may come through this channel.”

    The origin of such worlds’ mutually inclined orbits is another mystery, since planets are thought to form in the same plane from a flat disk of dust and gas surrounding a newborn star. Gravitational interactions among young planets may yank some of them askew, leading to tilted orbits, Dawson said.

    The new study, which was published online today (Oct. 9) in the journal Science, doesn’t necessarily suggest that Earth’s solar system is an oddball because it has planets that orbit in the same plane.

    “I wouldn’t say flat systems are rare; the compact systems of small planets discovered in abundance by the Kepler mission are statistically consistent with being mostly flat,” Dawson said.

    NASA Kepler Telescope
    NASA/ Kepler

    NASA’s Kepler spacecraft launched in 2009 to determine how commonly Earth-like planets occur in the Milky Way galaxy. The $600 million mission has spotted nearly 1,000 exoplanets, with more than 3,000 others awaiting confirmation by follow-up observations and analysis.

    Kepler’s original planet hunt came to an end in May 2013, when the second of the spacecraft’s four orientation-maintaining reaction wheels failed, robbing the telescope of its superprecise pointing ability. Kepler has now embarked on a new mission called K2, during which it will scan the skies for a number of cosmic objects and phenomena.

    See the full article here.

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  • richardmitnick 6:20 pm on October 9, 2014 Permalink | Reply
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    From SPACE.com: “Strange ‘Hybrid Star’ Discovered After 40-Year Search” 

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    October 09, 2014
    Charles Q. Choi

    For astronomers, it’s the equivalent of buried treasure in space: a strange hybrid star — actually, one star packed inside the shell of another, larger star.

    star
    An image showing the location of the first suspected Thorne-Zytkow object (TZO), a long-theorized hybrid star thought to form when a red supergiant swallows a neutron star. This likely TZO, known as HV 2112, lies in the Small Magellanic Cloud, about 200,000 light-years from Earth.
    Credit: Phil Massey, Lowell Observatory

    That’s apparently what happens when a dying star swallows a smaller, dead star. And for decades, this exotic cosmic rarity was only theory, a wild idea hatched by an astronomer and a now-famous physicist and an astronomer.

    It’s called a Thorne-Zytkow object (TZO), and its existence was first proposed in 1975 by physicist Kip Thorne and astronomer Anna Zytkow. TZOs The strange hybrid stars are theorized to form from binary systems containing two massive stars — a neutron star and a red supergiant star.

    Neutron stars are extraordinarily dense corpses of normal stars. Red supergiants are dying stars with the greatest diameters of any star in the universe, ranging from 200 to 2,000 times wider than the sun — “so big that if you placed them where our sun is, they would extend out to, or even beyond, the orbit of Saturn,” said study lead author Emily Levesque, an astrophysicist at the University of Colorado at Boulder.

    The news study, which details the likely discovery of the Thorne-Zytkow object, was published in the Sept. 1 issue of the journal MNRAS Letters. News of the find first came out, and was previewed in June, shortly after the study was submitted to the online preprint site arxiv.org.

    The hunt for a hybrid star

    A TZO is typically thought to form when a red supergiant engulfs an orbiting neutron star. The merger would result in “a shell of burning material around the neutron core — a shell that would generate new elements as it burned,” Thorne said in a statement. “Convection, the circulation of hot gas inside the star, would reach right into the burning shell and carry the products of burning all the way to the surface of the star long before the burning was complete.”

    A TZO should appear virtually identical to a very bright red supergiant. However, a TZO’s unique innards should produce unusually large amounts of rubidium, strontium, yttrium, zirconium, molybdenum and lithium, setting it apart from a normal red supergiant.

    Now, scientists have detected a red supergiant with the distinct chemical signature of a TZO, suggesting they may have detected these space oddities for the first time.

    “I am extremely happy that observational confirmation of our theoretical prediction has started to emerge,” Zytkow said in a June statement.

    In a galaxy not so far away

    The candidate TZO is named HV 2112. The star is a member of the Small Magellanic Cloud, a dwarf galaxy about 199,000 light-years away that is a close neighbor of the Milky Way and easily visible to the naked eye from the Southern Hemisphere.

    The researchers identified HV 2112 after a survey of 62 red supergiants conducted with the 6.5-meter (21.3 feet) Magellan Clay telescope in Chile and the Apache Point Observatory 3.5-meter (11.5 feet) telescope in New Mexico.

    Magellan 6.5 meter telescopes
    Magellan 6.5 meter Interior
    Magellan 6.5 meter telescope

    Apache Point Observatory
    Apache Point Observatory interior
    Apache Point Observatory

    “On our first night at the Magellan telescope, we had a fantastic ‘Hmmm, that’s odd’ moment,” Levesque told Space.com. “We were displaying the raw data as we took it, and when one star’s data popped up, we could tell, even in that messy format, that the spectrum was unusual. Our co-author Nidia Morrell [of the Carnegie Observatories in La Serena, Chile] looked at the data for this star and immediately said, ‘I don’t know what it is, but I know that I like it!'”

    “It was our first inkling that there was something different about this star,” Levesque said. “And that star turned out to be HV 2112.”

    The scientists confirmed excess levels of rubidium, molybdenum and lithium in HV 2112’s gaseous shroud.

    “If HV 2112 is found to be a bona fide TZO, this would have huge implications,” Levesque said. “It could offer the first solid evidence for a completely different model of how stars’ interiors can work. Inside these stars, we also have a new way of producing elements, and knowing where the various elements come from is a critical ingredient in trying to understand how the universe works. We hear that everything is made of ‘star stuff’ — inside TZOs, we might have found a totally new way to make some of it.”
    Is it really there?

    The evidence that HV 2112 is a TZO is strong “but not ironclad,” Thorne said in a statement. “Certainly it’s by far the best candidate for a TZO that anyone has seen, but additional confirmation is needed.”

    Although HV 2112 looks exactly how the researchers expected a TZO to look, “some of those expectations are based on models and predictions from a couple of decades ago,” Levesque said. “It’s possible that when modern-day models are run, they will give us new things to look for or new ideas of what a TZO might look like.”

    Levesque noted that she had already “gotten dozens of emails from people who are interested in running their own new computer models to test how TZO interiors work, how they might form or evolve, or even whether or not they can stably exist. “A few months ago, TZOs were an interesting but somewhat obscure topic, but our discovery has spurred a renewed interest in these stars,” Levesque said. “Whether people are criticizing our findings or setting out to prove us wrong honestly matters less to me than the fact that new research on TZOs is underway — the more people study them, the more we’ll know!”

    Levesque said that after she and her colleagues get more information on what modern-day models predict TZOs should look like, they would like to get more observations of HV 2112 and its surroundings “to see if there are any other strange quirks or tell-tale signs of it being a TZO.”

    “Searching for more TZOs would obviously be exciting, too,” Levesque added. “Finding one is interesting, but if we find several, we’ll be able to learn so much more.”

    See the full article here.

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  • richardmitnick 5:41 pm on September 30, 2014 Permalink | Reply
    Tags: , , , , , , space.com   

    From SPACE.com: “Search for Alien Life Should Target Water, Oxygen and Chlorophyll” 

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    SPACE.com

    September 30, 2014
    Mike Wall

    The next generation of space telescopes hunting for signs of extraterrestrial life should focus on water, then oxygen and then alien versions of the plant chemical chlorophyll, a new study suggests.

    In the past 20 years or so, astronomers have confirmed the existence of nearly 2,000 worlds outside Earth’s solar system. Many of these exoplanets lie in the habitable zones of stars, areas potentially warm enough for the worlds to harbor liquid water on their surfaces. Astrobiologists hope that life may someday be spotted on such alien planets, since there is life pretty much everywhere water exists on Earth.

    One strategy to discover signs of such alien life involves looking for ways that organisms might change a world’s appearance. For example, chemicals typically shape what are known as the spectra seen from planets by adding or removing wavelengths of light. Alien-hunting telescopes could look for spectra that reveal chemicals associated with life. In other words, these searches would focus on biosignatures — chemicals or combinations of chemicals that life could produce, but that processes other than life could not or would be unlikely to create.

    Astrophysicists Timothy Brandt and David Spiegel at the Institute for Advanced Study in Princeton, New Jersey, sought to see how challenging it might be to conclusively identify signatures of water, oxygen and chlorophyll — the green pigment that plants use to convert sunlight to energy — on a distant twin of Earth using a future off-Earth instrument such as NASA’s proposed Advanced Technology Large-Aperture Space Telescope (ATLAST).

    atlast
    8-meter monolithic mirror telescope (credit: MSFC Advanced Concepts Office)
    again
    16-meter segmented mirror telescope (credit: Northrop Grumman Aerospace Systems & NASA/STScI)
    two conceptual schemes for ATLAST

    The scientists found that water would be the easiest to detect.

    “Water is a very common molecule, and I think a mission to take spectra of exoplanets should certainly look for water,” said Brandt, the lead study author. “Indeed, we have found water in a few gas giants more massive than Jupiter orbiting other stars.”

    In comparison, oxygen is more difficult to detect than previously thought, requiring scientific instruments approximately twice as sensitive as those needed to detect water and significantly better at discriminating between similar colors of light.

    “Oxygen, however, has only been a large part of Earth’s atmosphere for a few hundred million years,” Brandt said. “If we see it in an exoplanet, it probably points to life, but not finding oxygen certainly does not mean that the planet is sterile.”

    Although a well-designed space telescope could detect water and oxygen on a nearby Earth twin, the astrophysicists found the instrument would need to be significantly more sensitive, or very lucky, to see chlorophyll. Identifying this chemical typically requires scientific instruments about six times more sensitive than those needed for oxygen. Chlorophyll becomes as detectable as oxygen only when an exoplanet has a lot of vegetation and/or little in the way of cloud cover, researchers said.

    Chlorophyll slightly reddens the light from Earth. If extraterrestrial life does convert sunlight to energy as plants do, scientists expect that the alien process might use a different pigment than chlorophyll. But alien photosynthesis could also slightly redden planets, just as chlorophyll does.

    “Light comes in packets called photons, and only photons with at least a certain amount of energy are useful for photosynthesis,” Brandt said. Chlorophyll reflects photons that are too red and low in energy to be used for photosynthesis, and it may be reasonable to assume that extraterrestrial pigments would do the same thing, Brandt noted.

    The researchers suggest a strategy for discovering Earthlike alien life that first looks for water, then oxygen on the more favorable planets and finally chlorophyll on only the most exceptionally promising worlds.

    “The goal of a future space telescope will be primarily to detect water and oxygen on a planet around a nearby star,” Brandt said. “The construction and launch of such a telescope will probably cost at least $10 billion and won’t happen for at least 20 years — a lot of technology development needs to happen first — but it could be the most exciting mission of my lifetime.”

    Brandt and Spiegel detailed their findings online Sept. 1 in the journal Proceedings of the National Academy of Sciences.

    See the full article here.

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  • richardmitnick 9:16 pm on September 28, 2014 Permalink | Reply
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    From SPACE.com: ” NASA Exoplanet Mission to Hunt Down Earth-sized Worlds” 

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    SPACE.com

    September 28, 2014
    Nola Taylor Redd

    Set to launch in 2017, NASA’s Transiting Exoplanet Survey Satellite (TESS) will monitor more than half a million stars over its two-year mission, with a focus on the smallest, brightest stellar objects.

    tess
    NASA/TESS

    During its observations, TESS is expected to find more than 3,000 new planets outside of our solar system, most of which will be possible for ground-based telescopes to observe.

    “Bright host stars are the best ones for follow-up studies of their exoplanets to pin down planet masses, and to characterize planet atmospheres,” said TESS principal investigator George Ricker, of the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics, in an email.

    “TESS should be able to find over 200 Earths and super-Earths — defined as being twice the size of Earth,” said Peter Sullivan, a physics doctoral student at MIT. “Ten to 20 of those are habitable-zone planets.”

    Sullivan, who works with Ricker on TESS, led an analysis of the number of planets TESS would likely find based on the number and types of planets found by NASA’s Kepler mission. Kepler focused on a single region of the sky and studied all transiting planets within it. TESS, on the other hand, will examine almost the entire sky over its two-year mission, but capture only the brightest stars, many of which are expected to host terrestrial planets.

    NASA Kepler Telescope
    NASA/Kepler

    A bounty of Earth-sized extrasolar planets

    TESS will travel around Earth in a highly elliptical orbit that will range as distant as the moon. Along the way, it will use four cameras to observe a swatch of sky running from the celestial equator to the poles. TESS will observe each swatch for approximately a month before switching to the next region.

    Courtney Dressing, a doctoral student at the Harvard-Smithsonian Center for Astrophysics, compares the satellite’s observations to peeling an apple in vertical cuts that overlap near the stem. Because of the overlap, stars near the pole will be observed for more than 100 days, while stars near the equator will be observed for only 27 days.

    Dressing worked on a second model, based on Sullivan’s work, that predicts the number of planets near Earth that pass between the sun and their host star.

    “We predicted there should be about 100 transiting planets within 20 parsecs [about 65 light-years], and that roughly three of them should lie within the habitable zone of their host stars,” Dressing said.

    Not all of these planets will be detectable to the TESS mission. According to Dressing, the new telescope will be most sensitive to small planets orbiting stars 20 to 50 percent the size of our sun.

    Because TESS focuses on small, bright stars, it will be sensitive to Earth-sized planets and the massive terrestrial planets known as super-Earths. Like Kepler, TESS will measure the dip in light that occurs when a planet passes between its star and Earth, known as its transit. These dips will be larger and easier to spot for Earth-sized planets, which should dominate the population of small stars. Larger planets will also be visible, though they are expected to be less common around TESS’s targets.

    “A lot of Jupiter-sized planets have been detected from the ground, however, so we’re more excited about TESS finding small planets that can efficiently be found from space,” Sullivan said.

    A wealth of knowledge

    One of the most exciting things about the upcoming bonanza of planets TESS should find is the ability to study them with ground-based telescopes. Such observations will allow scientists to learn more about the planets, including characterizing their masses and studying their atmospheres.

    “Some of the planets detected by Kepler orbit stars that are too faint for ground-based follow-up observations,” Dressing said.

    Unable to study the planets from the ground, scientists cannot calculate their masses or understand more about the stars they orbit. By targeting bright stars, TESS seeks to overcome these challenges.

    “When observing bright stars, astronomers can use ground-based instruments to make very accurate measurements of the sizes, temperatures and masses of the stars hosting the planets,” Dressing said.

    TESS will also target stars ideal for NASA’s James Webb Space Telescope (JSWST) to observe. While TESS will make the initial brief detections, JWST will allow for the more detailed follow-up that will provide greater insights about the stars and their planets. The mission is expected to launch a little over a year after TESS, allowing for a wealth of potential targets.

    NASA Webb Telescope
    NASA/Webb

    “TESS will observe a portion of the sky for about 300 days,” Ricker said. “This special area is the ‘sweet spot’ for the JWST mission.”

    According to Sullivan’s model, TESS is expected to find between 10 and 20 Earths and super-Earths in the habitable zone of their stars. Sullivan’s simulation, which compared the changes in brightness of the expected number of transiting planets to a model of TESS’s sensitivity, used a broad definition of the habitable zone, where a planet would be capable of hosting water on its surface.

    “Under more strict habitable zone definitions, TESS would still find 5 to 10 small planets,” Sullivan said.

    To formally detect a planet, Sullivan said, TESS must observe two transits of a planet, which will enable scientists to locate the planet again and study it from the ground. The researchers won’t toss out single-detection sources, however. The most interesting may become targets for other telescopes.

    “TESS will find some interesting long-period planets with only one detection, but it will just take more resources to confirm these detections,” Sullivan said.

    This story was provided by Astrobiology Magazine, a web-based publication sponsored by the NASA astrobiology program.

    See the full article, with video, here.

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  • richardmitnick 4:24 pm on September 25, 2014 Permalink | Reply
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    From SPACE.com: “Newfound Molecule in Space Dust Offers Clues to Life’s Origins” 

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    SPACE.com

    September 25, 2014
    Megan Gannon

    The discovery of a strangely branched organic molecule in the depths of interstellar space has capped a decades-long search for the carbon-bearing stuff.

    life
    The organic molecule iso-propyl cyanide has a branched carbon backbone (i-C3H7CN, left), unlike its straight-chain isomer normal-propyl cyanide (n-C3H7CN, right). Both molecules were detected with ALMA in Sagittarius B2. Credit: MPIfR/A. Weiss, University of Cologne/M. Koerber, MPIfR/A. Belloche

    The molecule in question — iso-propyl cyanide (i-C3H7CN) — was spotted in Sagittarius B2, a huge star-making cloud of gas and dust near the center of the Milky Way, about 27,000 light-years from the sun. The discovery suggests that some of the key ingredients for life on Earth could have originated in interstellar space.

    A specific molecule emits light at a particular wavelength and in a telltale pattern, or spectrum, which scientists can detect using radio telescopes. For this study, astronomers used the enormous Atacama Large Millimeter/submillimeter Array (ALMA) telescope in the Chilean desert, which went online last year and combines the power of 66 radio antennas.

    ALMA Array
    ALMA Array

    Iso-propyl cyanide joins a long list of molecules detected in interstellar space. But what makes this discovery significant is the structure of iso-propyl cyanide. All other organic molecules that have been detected in space so far (including normal-propyl cyanide, the sister of i-C3H7CN) are made of a straight chain with a carbon backbone. Iso-propyl cyanide, however, has a “branched” structure. This same type of branched structure is a key characteristic of amino acids.

    “Amino acids are the building blocks of proteins, which are important ingredients of life on Earth,” the study’s lead author, Arnaud Belloche, of the Max Planck Institute for Radio Astronomy, told Space.com in an email. “We are interested in the origin of amino acids in general and their distribution in our galaxy.”

    alma
    The central region of the Milky Way can be seen above the antennas of the ALMA observatory in Chile.

    Scientists have previously found amino acids in meteorites that fell to Earth, and the composition of these chemicals suggested they had an interstellar origin. The researchers in this new study did not find amino acids, but their discovery adds an “additional piece of evidence that the amino acids found in meteorites could have been formed in the interstellar medium,” Belloche wrote.

    “The detection of a molecule with a branched carbon backbone in interstellar space, in a region where stars are being formed, is interesting because it shows that interstellar chemistry is indeed capable of producing molecules with such a complex, branched structure,” Belloche added.

    It was first suggested in the 1980s that branched molecules could form on the surface of dust grains in interstellar space. But this is the first time such compounds have been detected. What’s more, iso-propyl cyanide seemed to be plentiful — it was almost half as abundant of its more common sister variant in Sagittarius B2, the study found. This means that branched molecules could actually be quite ordinary in interstellar space, the researchers said.

    The research is detailed in the Sept. 26 edition of the journal Science.

    See the full article here.

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  • richardmitnick 4:08 pm on September 25, 2014 Permalink | Reply
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    From SPACE.com: “Much of Earth’s Water Is Older Than the Sun” 

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    SPACE.com

    September 25, 2014
    Mike Wall

    Much of the water on Earth and elsewhere in the solar system likely predates the birth of the sun, a new study reports.

    space
    Planets form in the presence of abundant interstellar water inherited as ices from the parent molecular cloud.
    Credit: NASA/JPL-Caltech/R. Hurt (SSC-Caltech)/ESO/J. Emerson/VISTA/Cambridge Astronomical Survey Unit

    The finding suggests that water is commonly incorporated into newly forming planets throughout the Milky Way galaxy and beyond, researchers said — good news for anyone hoping that Earth isn’t the only world to host life.

    “The implications of our study are that interstellar water-ice remarkably survived the incredibly violent process of stellar birth to then be incorporated into planetary bodies,” study lead author Ilse Cleeves, an astronomy Ph.D. student at the University of Michigan, told Space.com via email.

    “If our sun’s formation was typical, interstellar ices, including water, likely survive and are a common ingredient during the formation of all extrasolar systems,” Cleeves added. “This is particularly exciting given the number of confirmed extrasolar planetary systems to date — that they, too, had access to abundant, life-fostering water during their formation.”

    Astronomers have discovered nearly 2,000 exoplanets so far, and many billions likely lurk undetected in the depths of space. On average, every Milky Way star is thought to host at least one planet.

    water
    Artist’s concept showing the time sequence of water ice, starting in the sun’s parent molecular cloud, traveling through the stages of star formation, and eventually being incorporated into the planetary system itself.
    Credit: Bill Saxton, NSF/AUI/NRAO

    Water, water everywhere

    Our solar system abounds with water. Oceans of it slosh about not only on Earth’s surface but also beneath the icy shells of Jupiter’s moon Europa and the Saturn satellite Enceladus. And water ice is found on Earth’s moon, on comets, at the Martian poles and even inside shadowed craters on Mercury, the planet closest to the sun.

    Cleeves and her colleagues wanted to know where all this water came from.

    “Why is this important? If water in the early solar system was primarily inherited as ice from interstellar space, then it is likely that similar ices, along with the prebiotic organic matter that they contain, are abundant in most or all protoplanetary disks around forming stars,” study co-author Conel Alexander, of the Carnegie Institution for Science in Washington, D.C., said in a statement.

    “But if the early solar system’s water was largely the result of local chemical processing during the sun’s birth, then it is possible that the abundance of water varies considerably in forming planetary systems, which would obviously have implications for the potential for the emergence of life elsewhere,” Alexander added.

    Heavy and ‘normal’ water

    Not all water is “standard” H2O. Some water molecules contain deuterium, a heavy isotope of hydrogen that contains one proton and one neutron in its nucleus. (Isotopes are different versions of an element whose atoms have the same number of protons, but different numbers of neutrons. The most common hydrogen isotope, known as protium, for example, has one proton but no neutrons.)

    Because they have different masses, deuterium and protium behave differently during chemical reactions. Some environments are thus more conducive to the formation of “heavy” water — including super-cold places like interstellar space.

    The researchers constructed models that simulated reactions within a protoplanetary disk, in an effort to determine if processes during the early days of the solar system could have generated the concentrations of heavy water observed today in Earth’s oceans, cometary material and meteorite samples.

    The team reset deuterium levels to zero at the beginning of the simulations, then watched to see if enough deuterium-enriched ice could be produced within 1 million years — a standard lifetime for planet-forming disks.

    The answer was no. The results suggest that up to 30 to 50 percent of Earth’s ocean water and perhaps 60 to 100 percent of the water on comets originally formed in interstellar space, before the sun was born. (These are the high-end estimates generated by the simulations; the low-end estimates suggest that at least 7 percent of ocean water and at least 14 percent of comet water predates the sun.)

    While these findings, published online today (Sept. 25) in the journal Science, will doubtless be of interest to astrobiologists, they also resonated with Cleeves on a personal level, she said.

    “A significant fraction of Earth’s water is likely incredibly old, so old that it predates the Earth itself,” Cleeves said. “For me, uncovering these kinds of direct links between our daily experience and the galaxy at large is fascinating and puts a wonderful perspective on our place in the universe.”

    See the full article here.

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