Dr. Freund's Multiversum
RSS-Feed-Reader: Seite wird geladen ...
Der freie RSS-Feed-Reader mit einfacher Feed-Verwaltung und Unterstützung der Google Chrome Erweiterung RSS-Abonnement. Keine Registrierung erforderlich.
URL: http://www.drfreund.net/rss_reader.htm?feedurl=http%3A%2F%2Fwww.spacedaily.com%2...
Grösse (Server): 3kB
anchor_pagestart

RSS-Feed-Reader

Feed-URL:
Titel (optional):
 Anzeige-Modus:      
Hilfe
Beschreibung:
Bisher angezeigte RSS-Feeds Zuletzt angezeigt Modus Jetzt anzeigen im Markieren
1. http://www.spacedaily.com/Exo_Worlds.xml  Mi, 24.10.2018 04:42:02  Alles  RSS-Reader Browser
Bitte Cookies aktivieren
Damit eine vollständige Liste der von Dir aufgerufenen RSS-Feeds angeboten werden kann, muss Dein Browser Cookies annehmen.
Der Inhalt dieser Cookies wird ausschliesslich auf Deinem lokalen Rechner gespeichert und ansonsten zu keinen Auswertungen herangezogen.
Siehe auch: Cookie-Policy
Inhalt von "http://www.spacedaily.com/Exo_Worlds.xml"
Anzeige-Modus: Alles (alle Einträge mit allen Links, Multimedia-Anhängen und Bildern in Originalgrösse, Text mit Zeilenumbrüchen)
Request 1
Ziel: http://www.spacedaily.com/Exo_Worlds.xml
Accept-Encoding: gzip,deflate

Response 1
Protokoll: HTTP/1.1
Status: 200
Statustext: OK
Content-type: text/xml
Content-Length: 50192
Last-Modified: Fri, 19 Oct 2018 10:25:57 GMT
ETag: "809f44-c410-57892543a9122"
Zeilen gesamt: 312
Zeilen Header: 9
Zeilen Body: 302
Chunks: 0

[Datenquelle validieren]

Free Daily Newsletters
Subscribe to our daily selection of space, military, environment and energy newsletters
  • Double dust ring test could spot migrating planets
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    Double dust ring test could spot migrating planets Warwick UK (SPX) Oct 19, 2018 -
    New research by a team led by an astrophysicist at the University of Warwick has a way of finally telling whether newly forming planets are migrating within the disc of dust and gas that typically surrounds stars or whether they are simply staying put in the same orbit around the star.Finding real evidence that a planet is migrating (usually inwards) within such discs would help solve a number of problems that have emerged as astronomers are able to see more and more detail within protoplanetary discs. In particular it might provide a simple explanation for a range of strange patterns and disturbances that astronomers are beginning to identify within these discs.Planet migration is a process that astronomers have known the theory about for 40 years but it's only now that they have been able to find a way of observationally testing if it really occurs. This new research from a team led by the University of Warwick, along with Cambridge, provides two new observational signatures in young solar system's dust rings that would be evidence of a migrating planet.That research was published 17th of October on arXiv AT in a paper entitled "Is the ring inside or outside the planet?: The effect of planet migration on dust rings" which will be published in the Monthly Notices of the Royal Astronomical Society.The lead author, Dr Farzana Meru of the University of Warwick's Astronomy and Astrophysics Group in the Department of Physics, on the paper said:"Planet migration in protoplanetary discs plays an important role in the longer term evolution of planetary systems, yet we currently have no direct observational test to determine if a planet is migrating in its gaseous disc."However the technology now available to us in the Atacama Large Millimeter/submillimeter Array (ALMA), is able to look deep into these discs, and even see detailed structures within the discs such as rings, gaps, spiral arms, crescents and clumps. ALMA can also use different millimetre frequencies to seek out concentrations of different particle sizes so we can also use it to explore the make up of individual dust rings within the disc""Our latest research has found a way to use this new technology to spot what we think will be a clear signature within these dust rings that the planet closest to them is actually migrating within that very young solar system."The University of Warwick led research team have concluded that if ALMA looks at the two dust rings nearest the orbit of a planet a simple measurement of the typical particle size in each ring will reveal the answer.If ALMA finds that the interior dust ring (i.e. between the planet's orbit and the star) is typically made up of smaller sized particles, and that the exterior dust ring (immediately outside of the planet's orbit) is typically made up of larger particles, then that will be clear evidence that the planet is migrating within the system's protoplanetary disc.The size of the particles would differ for each disc but in a case where the planet is located 30 astronomical units from the star and is 30 times the mass of the Earth, the smaller particles in the inner ring would typically be less than a millimetre in size, whereas those in the outer ring would be a little over a millimetre.ALMA will be able to observe this because the wavelength at which it observes roughly correlates with the dust particle size. This means that as observers look at the disc with ALMA at increasing wavelengths, the interior dust ring is expected to fade, while the exterior ring would become brighter.The reason for this pattern is twofold. Firstly the researchers' model shows that the exterior dust ring will contain more large dust particles because they move at a higher velocity (than the smaller particles) and are fast enough to keep up with the planet as it orbits inwards. This will result in a ring exterior to the planet's orbit that is mostly made up of large particles.Secondly, the inner ring consists of small particles because they move inwards more slowly than the planet. Consequently they are unable to get out of the way of the inwardly migrating planet and so accumulate in a ring just inwards of the planet. This time the fast-moving large dust moves rapidly towards the star leaving an interior dust ring of small-sized particles.The research team will continue to simulate what such ALMA observations would look like and astronomers can now use this method in their own ALMA observations to look for this two ring signature.However Dr Farzana Meru also notes that: "It may be the case that there are ALMA observations of protoplanetary discs that have already seen and recorded this dust ring signature while looking for other phenomena. If the same disc has been observed at different wavelengths - possibly by different teams - then a comparison of these observations might already be able to provide confirmation of our theory."Research paper
  • Algorithm takes search for habitable planets to the next level
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Algorithm takes search for habitable planets to the next level Thuwal, Saudi Arabia (SPX) Oct 19, 2018 -
    An international team of scientists, including high performance computing (HPC) experts from the King Abdullah University for Science and Technology (KAUST), astronomers from the Paris Observatory and the National Astronomical Observatory of Japan (NAOJ), in collaboration with NVIDIA, is taking the search for habitable planets and observation of first epoch galaxies to the next level.On-sky demonstration was recently achieved on NAOJ's 8.2-meter Subaru Telescope, and the Paris Observatory's team is already scaling up the algorithms for future larger telescopes. KAUST's Extreme Computing Research Center (ECRC) is working with the astronomers to develop the advanced Extreme-AO algorithms that will meet the formidable habitable exoplanet imaging challenge."Imaging exoplanets with large, ground-based telescopes is very challenging due to the star/planet contrast and blurring induced by Earth's atmosphere. Very high-performance adaptive optics, sometimes referred to as 'Extreme-AO,' are required," says Dr. Hatem Ltaief, Senior Research Scientist in the Extreme Computing Research Center at King Abdullah University for Science and Technology (KAUST).A radically new approach to AO has emerged from this collaboration: faster, bigger, and much smarter control algorithms. Powered by KAUST's linear algebra code running on NVIDIA graphics processing units (GPUs), the new computational system continuously optimizes itself, and even learns to anticipate fast-changing optical disturbances induced by Earth's atmosphere."This fantastic new technology is already being used to take a closer look at exoplanets orbiting around nearby stars. With the larger 25-40m telescopes astronomers are currently building, new Earth-like planets orbiting nearby stars will be imaged and their atmospheric composition will be measured to look for signs of life such as oxygen, water or methane," says Professor Damien Gratadour, an astronomer at the Paris Observatory.ECRC researchers at KAUST recently implemented a new Singular Value Decomposition (SVD) algorithm, often referred as the workhorse for numerical linear algebra, to optimally control a small high-speed deformable mirror to compensate for atmospheric turbulence.This research resulted in one of the best paper awards at the Platform for Advanced Scientific Computing (PASC) Conference 2018 in Basel, Switzerland. The innovation is already successfully used by astronomers to image exoplanets with the 8.2m diameter Subaru Telescope located at 14,000 feet elevation in Hawaii."This challenge is further exacerbated with large telescopes, where imaging habitable planets through Earth's atmosphere is notoriously difficult, and requires a new approach to adaptive optics. Our previous AO systems were quite slow and lagging behind the fast-changing optical aberration due to atmospheric turbulence.The SVD algorithm developed by KAUST scientists is enabling us to correct in real-time for atmospheric blurring of images taken by large telescopes using smarter Extreme-AO. The algorithm now learns to optimize itself, and we are no longer outsmarted by turbulence," says Professor Oliver Guyon, astronomer at the Subaru Telescope in Hawaii.Working closely with NVIDIA has been critical to the success of the project. "This is an unprecedented HPC challenge. Optical aberrations induced by atmosphere change over millisecond timescale. On current large telescopes, algorithms must compute thousands of deformable actuator positions in a millisecond or less to sharpen images.The Subaru Telescope is the highest recorded terrestrial use of these kind of GPU systems. We are continuing to work with the team as the hardware is scaled up for this exciting project due to the critical performance impact of NVIDIA GPUs," says Steve Oberlin, Chief Technology Officer for Accelerated Computing at NVIDIA.The work of the project team adds to the historic contribution of the Middle East into the field of astronomy. "We are helping astronomers make better use of today and tomorrow's most advanced telescopes. Interestingly many of the stars we are observing with the Subaru Telescope were first sighted by stargazers in the region and have retained their Arabic names. We hope to contribute to the tradition of astronomy in the region," notes Dr. Ltaief.KAUST's HPC solutions are also becoming a critical part in the design of future instruments aimed at imaging the most distant galaxies. Moving forward, ECRC researchers together with Paris Observatory and NAOJ's astronomers are defining a common roadmap for sustainable software development.
  • Giant planets around young star raise questions about how planets form
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    Giant planets around young star raise questions about how planets form Boston MA (SPX) Oct 19, 2018 -
    Researchers have identified a young star with four Jupiter and Saturn-sized planets in orbit around it, the first time that so many massive planets have been detected in such a young system.The system has also set a new record for the most extreme range of orbits yet observed: the outermost planet is more than a thousand times further from the star than the innermost one, which raises interesting questions about how such a system might have formed.The star is just two million years old - a 'toddler' in astronomical terms - and is surrounded by a huge disc of dust and ice. This disc, known as a protoplanetary disc, is where the planets, moons, asteroids and other astronomical objects in stellar systems form.The star was already known to be remarkable because it contains the first so-called hot Jupiter - a massive planet orbiting very close to its parent star - to have been discovered around such a young star.Although hot Jupiters were the first type of exoplanet to be discovered, their existence has long puzzled astronomers because they are often thought to be too close to their parent stars to have formed in situ.Now, a team of researchers led by the University of Cambridge have used the Atacama Large Millimeter/submillimeter Array (ALMA) to search for planetary 'siblings' to this infant hot Jupiter.Their image revealed three distinct gaps in the disc, which, according to their theoretical modelling, were most likely caused by three additional gas giant planets also orbiting the young star. Their results are reported in The Astrophysical Journal Letters.The star, CI Tau, is located about 500 light years away in a highly-productive stellar 'nursery' region of the galaxy. Its four planets differ greatly in their orbits: the closest (the hot Jupiter) is within the equivalent of the orbit of Mercury, while the farthest orbits at a distance more than three times greater than that of Neptune. The two outer planets are about the mass of Saturn, while the two inner planets are respectively around one and 10 times the mass of Jupiter.The discovery raises many questions for astronomers. Around 1% of stars host hot Jupiters, but most of the known hot Jupiters are hundreds of times older than CI Tau."It is currently impossible to say whether the extreme planetary architecture seen in CI Tau is common in hot Jupiter systems because the way that these sibling planets were detected - through their effect on the protoplanetary disc - would not work in older systems which no longer have a protoplanetary disc," said Professor Cathie Clarke from Cambridge's Institute of Astronomy, the study's first author.According to the researchers, it is also unclear whether the sibling planets played a role in driving the innermost planet into its ultra-close orbit, and whether this is a mechanism that works in making hot Jupiters in general. And a further mystery is how the outer two planets formed at all."Planet formation models tend to focus on being able to make the types of planets that have been observed already, so new discoveries don't necessarily fit the models," said Clarke."Saturn mass planets are supposed to form by first accumulating a solid core and then pulling in a layer of gas on top, but these processes are supposed to be very slow at large distances from the star. Most models will struggle to make planets of this mass at this distance."The task ahead will be to study this puzzling system at multiple wavelengths to get more clues about the properties of the disc and its planets. In the meantime, ALMA - the first telescope with the capability of imaging planets in the making - will likely throw out further surprises in other systems, re-shaping our picture of how planetary systems form.Research paper
  • Scientific research will help to understand the origin of life in the universe
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    Scientific research will help to understand the origin of life in the universe Samara, Russia (SPX) Oct 19, 2018 -
    Until now, in the scientific community there has been the prevailing view that thermal processes associated exclusively with the combustion and high-temperature processing of organic raw materials such as oil, coal, wood, garbage, food, tobacco underpin the formation of PAHs.However, the scientists from Samara University, together with their colleagues from the University of Hawaii, Florida International University, and Lawrence Berkeley National Laboratory proved that the chemical synthesis of PAHs can occur at very low temperatures, namely -183 C.Their attention to this topic was attracted, among other things, by the results of the NASA and the European Space Agency mission "Cassini-Huygens" to Saturn's largest moon, Titan. During the space mission of an automatic interplanetary station the benzene molecule was discovered in the atmosphere of Titan.This, in turn, led scientists to believe that the emergence and growth of the orange-brownish haze layers that surround this moon is exactly the responsibility of PAHs. However, the fundamental chemical mechanisms leading to the chemical synthesis of PAHs in the atmosphere of Titan at very low temperatures were not disclosed.Within the framework of the megagrant "Development of Physically Grounded Combustion Models" under the guidance of Professor of Florida International University Alexander Mebel, the scientists from Samara University searched for the mechanisms of PAH formation using modern high-precision quantum chemical calculation methods.Based on these data, their colleagues from the University of Hawaii and Lawrence Berkeley National Laboratory conducted laboratory experiments that confirmed that prototypes of PAH molecules (anthracene and phenanthrene) are synthesized in barrier-free reactions that take place at low temperatures typical of Titan atmosphere.Anthracene and phenanthrene, in turn, are the original "bricks" for larger PAH molecules, as well as precursors of more complex chemical compounds that were found in the orange-brownish organic haze layers surrounding the moon of Saturn."Experimental detection and theoretical description of these elementary chemical reactions change the well-established notion that PAHs can be formed and are able to grow only at very high temperatures, for example, in flames of organic fuels under terrestrial conditions, - concluded Alexander Mebel. - And this means that our discovery leads to the changing of existing scientific views on how PAHs can be formed and grow.""Traditionally, models of PAH synthesis in hydrocarbon-rich atmospheres of the planets and their moons, such as Titan, assumed the presence of high temperatures, - emphasizes Professor at the University of Hawaii Ralf Kaiser. We provide evidence for a low-temperature reaction pathway".Understanding the mechanism of PAH growth at low temperatures will allow scientists to understand how complex organic molecules that are related to the origin of life can be formed in the Universe."Molecules similar to small PAHs, but containing nitrogen atoms, are key components of ribonucleic acids (RNA, DNA) and some amino acids, that is, components of proteins, - notes Alexander Mebel. - Therefore, the growth mechanism of PAHs can be associated with chemical evolution in the Universe, leading to the origin of life".Moreover, the study of the atmosphere of Titan helps to understand the complex chemical processes occurring not only on the Earth, but also on other moons and planets. "Using new data, scientists can better understand the origin of life on the Earth at the time when nitrogen was more common in its atmosphere, as it is now on Titan", - said Musahid Ahmed, a scientist at Lawrence Berkeley National Laboratory.As for the application of the presented work it should be mentioned that the understanding the mechanism of PAH growth in flames will allow the scientists of Samara University to offer engineers the mechanisms to reduce the release of these carcinogenic substances in the exhaust of various types of engines. And this is one of the main goals of the megagrant implemented by the University.Research paper
  • How the seeds of planets take shape
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    How the seeds of planets take shape Pasadena CA (SPX) Oct 12, 2018 -
    In theoretical research that could explain everything from planet formation to outflows from stars, to even the settling of volcanic ash, Caltech researchers have discovered a new mechanism to explain how the act of dust moving through gas leads to clumps of dust. While dust clumps were already known to play a role in seeding new planets and many other systems in space and on Earth, how the clumps formed was unknown until now.Phil Hopkins, professor of theoretical astrophysics at Caltech, working with Jonathan (Jono) Squire, a former postdoctoral fellow at Caltech, began thinking about disturbances to dust moving through gas while studying how strong radiation from stars and galaxies drives dust-laden winds.Hopkins says that it was previously assumed that dust was stable in gas, meaning the dust grains would ride along with gas without much happening, or they would settle out of the gas if the particles were big enough, as is the case with soot from a fire."What Jono and I discovered is that dust and gas trying to move with one another is unstable and causes dust grains to come together," says Hopkins. "Soon we began to realize that these gas-dust instabilities are at play anywhere in the universe that a force pushes dust through gas, whether the forces are stellar winds, gravity, magnetism, or an electrical field." The team's simulations show material swirling together, with clumps of dust growing bigger and bigger."We actually started out studying dust-driven winds in space, but as we studied the problem, we noticed specific features of the instabilities that led us to think this was a more general phenomenon," says Squire, who together with Hopkins has authored four articles on their new findings, one published in The Astrophysical Journal and three in Monthly Notices of the Royal Astronomical Society."From here, it kind of snowballed, since we were able to study lots of different systems - galaxies, stars, planet formation, the gas close to supermassive black holes, supernovas, et cetera - and confirm our intuition. It wasn't a eureka moment but a series of eurekas that lasted about a week."Perhaps the most notable implications for the newfound Hopkins-Squire instabilities are for the study of burgeoning planets. Planets take shape within dusty, rotating "protoplanetary" disks of gas and dust around young stars. In these disks, the dust coalesces to form bigger and bigger pebbles and boulders, then mountain-size chunks, and eventually full-grown planets.At some point during this process, when the pieces of rock are big enough - about 1,000 kilometers in diameter - gravity takes over and smooshes the mountainous rocks into a round planet. The big mystery lies in what happens before gravity takes effect - that is, what is causing the dust particles, pebbles, and boulders to come together? Researchers once thought they might stick together in the same way dust bunnies accumulate under your bed, but there are problems with that theory."If you throw two pebbles together, they don't stick. They just bounce off each other," says Hopkins. "For sizes in between a millimeter and hundreds of kilometers, the grains don't stick. This is one of the biggest problems in modeling planet formation."In the Hopkins-Squire instability model, which builds on previous models of dust-gas interactions, the formation of planetary dust clumps would begin with tiny dust grains moving through the gas orbiting in a protoplanetary disk.Gas would curl around a grain like river water around a boulder; the same thing would happen with another grain of dust nearby. These two gas flows might then interact. If there are many dust grains in relatively close proximity to one another, which is the case in planet formation, the net effect of the many resulting gas flows would be to channel the dust together into clumps."In our new theory, this sticking through clumping can occur for a much wider range of grain sizes than previously thought, allowing smaller grains to participate in the process and rapidly grow in size," says Squire."Understanding the origins of our solar system ranks among the most important problems in all of natural science, and the discovery of the Hopkins-Squire instability is a significant step toward attaining that understanding. This is an exciting development," says Caltech's Konstantin Batygin, assistant professor of planetary science and Van Nuys Page Scholar, who was not involved in the study.The research team says these instabilities may also be important in completely different situations here on Earth. For instance, volcanic ash or raindrops interact with our atmosphere in exactly the same way that astrophysical dust interacts with its surrounding gas."It's very interesting to explore how these instabilities could operate in all these different scenarios," says Squire. "We're looking forward to understanding completely different instabilities in other areas of physics and applied mathematics - and, hopefully, to finding other entirely new and interesting systems where this occurs."References:
    * "The Resonant Drag Instability (RDI): Acoustic Modes," Philip F. Hopkins and Jonathan Squire, 2018 July 25, Monthly Notices of the Royal Astronomical Society.* "Ubiquitous Instabilities of Dust Moving in Magnetized Gas," Philip F. Hopkins and Jonathan Squire, 2018 June 18, Monthly Notices of the Royal Astronomical Society* "Resonant Drag Instabilities in Protoplanetary Discs: The Streaming Instability and New, Faster Growing Instabilities," Jonathan Squire and Philip F. Hopkins, 2018 Apr. 4, Monthly* "Resonant Drag Instability of Grains Streaming in Fluids," Jonathan Squire and Philip F. Hopkins, 2018 Mar. 23, Astrophysical Journal Letters
  • Boy meets world: Life-long space buff and Western graduate student discovers exoplanet
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    Boy meets world: Life-long space buff and Western graduate student discovers exoplanet London, Canada (SPX) Oct 12, 2018 -
    Ever since Chris Fox was a young boy, he wanted to visit alien planets. With no immediate plans for such a voyage, the Western University graduate student has done the next best thing. He's gone and found one.Teamed with Paul Wiegert, Graduate Program Director at Western's renowned Centre for Planetary Science and Exploration (CPSX), Fox discovered the exoplanet - provisionally known as Kepler 159d - by investigating gravitational effects on Kepler 159b and Kepler 159c.These two previously discovered exoplanets were detected by NASA's Kepler Space Telescope, an observatory in space charged with finding planets outside our solar system, particularly alien planets that are around the same size as Earth in the habitable regions of their parent star.Kepler 159d was not actually seen by Fox and Wiegert rather it was variations in the orbits of Kepler 159b and Kepler that allowed the planetary scientists to deduce its presence."I've been a space buff since I was a little kid, I watched all of the old sci-fi shows and I always wanted to go to another planet," says Fox. "We can't go to the planets quite yet, so this is as good as it gets for now."Kepler 159d has a mass comparable to that of Saturn, the second-largest planet in our solar system. And like Saturn, it is likely mostly composed of gases with no distinct solid surface.Whether Kepler 159d has rings or moons like Saturn is still unknown but what is known is that it orbits within its star's 'Habitable Zone,' which means temperatures are in the range suitable for Earth-life but there is no evidence on whether there is actually any life in the system.The central star of Kepler 159d's planetary system is a red dwarf star (spectral class M0V) with a mass estimated at 52 per cent of that of our Sun. Its surface temperature is about 3600 Celsius (3893 Kelvin) while the Sun's is 5500C (5770 K).Research paper
  • NASA should expand search for life in the universe: NAS Report
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    NASA should expand search for life in the universe: NAS Report Washington DC (SPX) Oct 11, 2018 -
    To advance the search for life in the universe, NASA should support research on a broader range of biosignatures and environments, and incorporate the field of astrobiology into all stages of future exploratory missions, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.Astrobiology, the study of the origin, evolution, distribution, and future of life in the universe, is a rapidly changing field, especially in the years since the publication of NASA's Astrobiology Strategy 2015. Recent scientific advances in the field now provide many opportunities to strengthen the role of astrobiology in NASA missions and to increase collaboration with other scientific fields and organizations. The report finds that these changes necessitate an updated science strategy for astrobiology.The committee that authored the report found that the lines of evidence we use to look for current and past life on Earth and beyond, called biosignatures, needs expansion.An updated, more sophisticated catalog and framework will be important to enhance our ability to detect both life that might be similar to terrestrial life, and potential life that differs from life as we know it. The latter will be enabled by investigating novel "agnostic" biosignatures - signs of life that are not tied to a particular metabolism or molecular "blueprint," or other characteristics of life as we currently know it.A comprehensive framework could also aid in distinguishing between biosignatures and abiotic (non-living) phenomena, and improve understanding of the potential for biosignatures to be preserved (or not) over long planetary time-scales. The report highlights the need to include in situ detection of energy-starved or otherwise sparsely distributed life such as chemolithotrophic or rock-eating life.In particular, the report found that NASA should focus on research and exploration of possible life below the surface of a planet in light of recent advances that have demonstrated the breadth and diversity of life below Earth's surface, the nature of fluids beneath the surface of Mars, and the likelihood of life-sustaining geological processes in planets and moons with subsurface oceans. A renewed focus on how to seek signs of subsurface life will inform astrobiology investigations of other rocky planets or moons, ocean or icy worlds, and beyond to exoplanets.The report emphasizes the need for NASA to ramp up efforts in developing mission-ready life detection technologies to advance the search for life. For studies of life on planets outside of this solar system, the agency should implement technologies in near-term ground- and space-based direct imaging missions that can suppress the light from stars.The specialized measurements, equipment, and analysis required to take full advantage of space missions include some that exist outside of traditional space science fields, highlighting the need for interdisciplinary, non-traditional cooperation and collaboration with organizations outside of NASA, the report says.So far, planning, implementation, and operations of planetary exploration missions with astrobiological objectives have tended to be more strongly defined by geological perspectives than by astrobiology-focused strategies. The committee recommended the integration of astrobiology into all mission stages, from inception to development and operations. Collaboration with private, philanthropic, and international organizations, especially international space agencies, is also crucial to achieving the objectives of searching for life in the universe.The committee also pointed out that adopting an interdisciplinary approach to astrobiology would produce a more complete picture of life on Earth as well as other planets. Integrating the physical, chemical, biological, geologic, planetary, and astrophysical sciences into the study of astrobiology will better show the relationship between life and its environment and how each changes, incorporating a new, dynamic view of habitability that includes consideration of multiple parameters. NASA should continue to actively seek new mechanisms to reduce the barriers to these potential collaborations, the report says.The study was sponsored by NASA. The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.
  • The stuff that planets are made of
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    The stuff that planets are made of Zurich, Switzerland (SPX) Oct 11, 2018 -
    Is there a second Earth out there in space? Our knowledge of planetary systems far, far away is increasing constantly, as new technologies continue to sharpen our gaze into space. To date, 3,700 planets have already been discovered outside our solar system.The planetary masses and radii of these exoplanets can be used to infer their mean density, but not their exact chemical composition and structure. The intriguing question about what these planets could look like is thus still open."Theoretically, we can assume various compositions, such as a world of pure water, a world of pure rock, and planets that have hydrogen-helium atmospheres and explore what radii are expected" explains Michael Lozovsky, a doctoral candidate in the group of Prof. Ravit Helled at the Institute for Computational Science at the University of Zurich.Thresholds for planetary composition
    Lozovsky and collaborators have used databases and statistical tools to characterize exoplanets and their atmospheres. These are fairly common and surrounded by a volatile layer of hydrogen and helium. However, the directly measured data previously didn't allow the researchers to determine the exact structure, since different compositions may lead to the same mass and radius.In addition to the accuracy of the data relating to mass and radius, the research team thus also investigated the assumed internal structure, temperature and reflected radiation in 83 of the 3,700 known planets, for which the masses and radii are well-determined."We used a statistical analysis to set limits on possible compositions. Using a database of detected exoplanets, we found that every theoretical planetary structure has a 'threshold radius', a planetary radius above which no planets of this composition exist," explains Michael Lozovsky.The amount of elements in the gaseous layer that are heavier than helium, the percentage of hydrogen and helium, as well as the distribution of elements in the atmosphere are important factors in determining the threshold radius.Super-Earths and mini-Neptunes
    The researchers from the Institute for Computational Science found that planets with a radius of up to 1.4 times that of Earth (6,371 kilometers) can be earth-like, i.e. they have a composition similar to Earth. Planets with radii above this threshold have a higher share of silicates or other light materials.Most of the planets with a radius above 1.6 radii of the Earth must have a layer of hydrogen-helium gas or water in addition to their rocky core, while those larger than 2.6 Earth radii can't be water worlds and therefore might be surrounded by an atmosphere. Planets with radii larger than 4 Earth radii are expected to be very gaseous and consist of at least 10 percent hydrogen and helium, similarly to Uranus and Neptune.The findings of the study provide new insights into the development and diversity of these planets. One particularly interesting threshold concerns the difference between large terrestrial-like planets - otherwise known as super-Earths - and small gaseous planets, also referred to as mini-Neptunes.According to the researchers, this threshold lies at a radius of three times that of Earth. Below this threshold, it is therefore possible to find earth-like planets in the vast expanse of the galaxy.M. Lozovsky, R. Helled, C. Dorn, and J. Venturini. Threshold Radii of Volatile-Rich Planets. Astrophysics. Astrophysical Journal. 9. October 2018, DOI: 10.3847/1538-4357/aadd09
  • Living organisms find a critical balance
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Weitere Links:
    Living organisms find a critical balance Tempe AZ (SPX) Oct 10, 2018 -
    Biologists know a lot about how life works, but they are still figuring out the big questions of why life exists, why it takes various shapes and sizes, and how life is able to amazingly adapt to fill every nook and cranny on Earth.An interdisciplinary team of researchers at Arizona State University has discovered that the answers to these questions may lie in the ability of life to find a middle ground, balancing between robustness and adaptability. The results of their study have been recently published in Physical Review Letters.The research team, led by Bryan Daniels of the Center for Biosocial Complex Systems with direction from faculty member Sara Walker of the School of Earth and Space Exploration, sifted through data to better understand the root connections among 67 biological networks that describe how components of these systems interact with one another.The biological networks are sets of individual components (like proteins and genes) that interact with one another to perform important tasks like transmitting signals or deciding a cell's fate. They measured a number of mathematical features, simulating the networks' behavior and looking for patterns to provide clues on what made them so special.To perform their study, they examined data from the Cell Collective database. This rich resource represents biological processes across life - encapsulating a wide range of biological processes from humans to animals, plants, bacteria and viruses. The number of components in these networks ranged from five nodes to 321 nodes, encompassing 6500 different biological interactions.And these nodes include many of life's key building blocks - genes and proteins that act as master switches controlling cell division, growth and death, and communication.Using a wealth of molecular data, scientists can now study the interactions among the building blocks, with an ultimate goal of understanding the key to how life emerges."We wanted to know whether the biological networks were special compared to random networks, and if so, how," says Daniels.They focused on trying to find a threshold point at which an entire system may change in response to just a small change. Such a change could profoundly upset the balance of life, creating a teeter-totter of fate deciding whether an organism would die or thrive."In a stable system, organisms will always come back to their original state," explains Daniels. "In an unstable system, the effect of a small change will grow and cause the whole system to behave differently."Through rigorous testing of the 67 networks, the team found that all of the networks shared a special property: They existed in between two extremes, neither too stable nor unstable.As such, the team found that sensitivity, which is a measure of stability, was near a special point that biologists call "criticality," suggesting that the networks may be evolutionarily adapted to an optimal tradeoff between stability and instability.Life in the balance
    Previous studies have shown that a handful of biological systems, from neurons to ant colonies, lie in this middle ground of criticality and this new research expands the list of living systems in this state.This can be of particular interest to astrobiologists, like co-author Walker who is searching for life on other planets. Understanding how life can take various forms, and why it does so, may help identify life on other planets and determine how it might look different from life on Earth. It can also help inform our search for the origins of life in the lab."We still don't really understand what life is," says Walker, "and determining what quantitative properties, such as criticality, best distinguish life from non-life is an important step toward building that understanding at a fundamental level so that we may recognize life on other worlds or in our experiments on Earth, even if it looks very different than us."The findings also advance the field of quantitative biology by showing that, from the basic building blocks of life, scientists can identify a critical sensitivity that is common across a large swath of biology. And it promises to advance synthetic biology by allowing scientists to use life's building blocks to more accurately construct biochemical networks that are similar to living systems."Each biological system has distinctive features, from its components and its size to its function and its interactions with the surrounding environment," explains co-author Hyunju Kim of the School of Earth and Space Exploration and the Beyond Center."In this research, for the first time, we are able to make connections between the theoretical hypothesis on biological systems' universal tendency to retain the balance at the medium degree of stability and 67 biological models with various characteristics built on actual experiment data."In addition to Daniels, Walker, and Kim, the interdisciplinary research team on this study includes co-authors Douglas Moore of the Beyond Center, Siyu Zhou of the Department of Physics, Bradley Karas and Harrison Smith of the School of Earth and Space Exploration, and Stuart Kauffman of the Institute for Systems Biology in Seattle, Washington.This research emerged from a course led by Walker and Kim on complex systems approaches to understanding life, offered at the School of Earth and Space Exploration. Co-authors Karas, Zhou, and Smith were originally students in the class when the project began."In our class project, the analytic tools and codes to study general dynamical systems were provided, and we gave the option for students to choose any dynamical systems they were interested in," says Kim."Students were asked to modify the analysis and codes to study various features of each selected system. As a result, we ended up dealing with many different biological networks, investigating more diverse aspects of those systems, and developed more codes and analysis tools, even after the completion of the class."Research paper
  • Construction of Europe's exoplanet hunter Plato begins
    Donnerstag, 18.10.2018, 23:32:49 Uhr
    Construction of Europe's exoplanet hunter Plato begins Paris (ESA) Oct 05, 2018 -
    The construction of ESA's Plato mission to find and study planets beyond our Solar System will be led by Germany's OHB System AG as prime contractor, marking the start of the full industrial phase of the project.The announcement was made this week at the 69th International Astronautical Congress in Bremen, Germany, where the contract was formally signed.The contract covers the delivery of the satellite, including the testing phase leading to launch, support during the launch campaign, and the in-orbit commissioning phase.Plato, the PLAnetary Transits and Oscillations of stars mission, will be launched in 2026 to find and study extrasolar planetary systems, with a special emphasis on rocky planets around Sun-like stars and their habitable zone - the distance from a star where liquid water can exist on a planet's surface."Does a second Earth exist in the Universe? is one of the exciting questions in astrophysics today," says Johann-Dietrich Worner, Director General of ESA."With our Plato satellite we are focusing on Earth-like planets orbiting up to the habitable zone around other stars which are similar to our Sun. This will be a major step towards finding another Earth."The spacecraft will be built and assembled by OHB together with Thales Alenia Space (France and the UK) and RUAG Space Switzerland; many ESA member States will also be involved in the construction of this European planet hunter.The German Aerospace Center (DLR) and a consortium of various European research centers and institutes will provide the scientific instrument, consisting of an array of 26 cameras and electronic units, that will observe a large patch of the sky on the lookout for planets."Plato is a next-generation exoplanet mission that will monitor thousands of bright stars over a large area of the sky in search of tiny, regular dips in their brightness caused by transiting planets," says Ana Heras, Plato project scientist at ESA."Since planets only block a minute portion of the light radiated by their parent star, this quest requires extremely precise, long-term photometric observations."Plato will not only seek new planets but will also investigate the properties of their host stars, and determine the planetary masses, sizes and ages with unprecedented accuracy. This will help scientists understand the architecture of exoplanet systems and determine whether they might host habitable worlds. In addition, Plato will also perform asteroseismology - the study of seismic activity of stars - providing insight into stellar interiors and evolution.The mission will expand on the work of Cheops, ESA's upcoming exoplanet watcher, which will be launched next year to perform a first characterisation of known planets. It will be followed by Ariel, scheduled for launch in 2028, which will observe a large and diverse sample of exoplanets to study their atmospheres in great detail.Plato will operate from the 'L2' virtual point in space 1.5 million km beyond Earth as seen from the Sun. From this vantage point, it will be our outpost to unravel the mysteries of a multitude of extrasolar worlds."We are pleased to kick off construction of this exciting mission," says Filippo Marliani, ESA's Plato Project Manager."With the prime contractor and the support of European space industry, we are looking forward to building a spacecraft that will tackle some of humankind's most profound questions."
Disclaimer:
Der auf dieser Seite verfügbar gemachte RSS-Reader ist ein reines Anzeige-Werkzeug ohne eigene Inhalte. Der Betreiber der Domain www.drfreund.net distanziert sich ausdrücklich von den Inhalten der angezeigten RSS-Feeds und macht sie sich nicht zu eigen. Die Rechte auf Texte, Bilder, Multimedia-Einbettungen und sonstige geschützte Bestandteile von angezeigten RSS-Feeds, sowie die alleinige Verantwortung für den gesamten Inhalt verbleiben beim jeweiligen Anbieter. Die Inhalte von RSS-Feeds werden in keinem Fall ohne vorherige explizite Eingabe bzw. Auswahl der entsprechenden URLs durch den jeweiligen Benutzer angezeigt. Der Betreiber der Domain www.drfreund.net übernimmt keine Verantwortung für einen versehentlichen oder absichtlichen Abruf von illegalen, jugendgefährdenden oder in sonst einer Weise rechtlich fragwürdigen Inhalten. Die Benutzung des RSS-Readers und das Vornehmen der empfohlenen Browser-Einstellungen geschieht auf eigene Gefahr.

 
Dr. Freund's Multiversum History von http://www.drfreund.net/rss_reader.htm?feedurl=http%3A%2F%2Fwww.spacedaily.com%2FExo_Worlds.xml&debug=1 Details zu http://www.drfreund.net/rss_reader.htm?feedurl=http%3A%2F%2Fwww.spacedaily.com%2FExo_Worlds.xml&debug=1  URL: http://www.drfreund.net/rss_reader.htm?feedurl=http%3A%2F%2Fwww.spacedaily.com%2...  Zwischenablage  Druckansicht von <RSS-Feed-Reader>
Powered by PHP Powered by SELFHTML  Letzte Aktualisierung: Sonntag, 07.10.2018, 00:06:54 Uhr  Technische Infos 
Valid HTML 5 Valid CSS! Browser: CCBot/2.0 (https://commoncrawl.org/faq/) Browser-Check Design-Ansicht von <RSS-Feed-Reader>
RSS-Feed von Dr. Freund's Multiversum Creative Commons - Some Rights Reserved            Cookie-Policy :: Disclaimer :: Impressum :: Kontakt: ten.dnuerfrd@dnuerfrd Gästebuch
Home :: Service :: WebNapping :: Meine Meinung :: Aktionen :: Links :: Partner :: Bannertausch :: Sitemap :: F.A.Q.
Herzlichen Glückwunsch! Du bist am normalerweise unsichtbaren Ende dieser Seite angekommen.
Wenn Du diesen Text lesen kannst, dann verwendest Du wahrscheinlich einen ungebräuchlichen
oder veralteten Browser, der moderne CSS-Stile nicht korrekt verarbeiten kann.
Auf jeden Fall unterstütze ich diesen Browser nicht. Sorry.


Download Firefox Download Google Chrome
Dr. Freund's Multiversum