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  • Largest haul of extrasolar planets for Japan
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    Largest haul of extrasolar planets for Japan Tokyo, Japan (SPX) Aug 08, 2018 -
    Forty-four planets in solar systems beyond our own have been unveiled in one go, dwarfing the usual number of confirmations from extrasolar surveys, which is typically a dozen or less. The findings will improve our models of solar systems and may help researchers investigate exoplanet atmospheres. Novel techniques developed to validate the find could hugely accelerate the confirmation of more extrasolar planet candidates.An international team of astronomers pooled data from U.S. space agency NASA's Kepler and the European Space Agency (ESA)'s Gaia space telescopes, as well as ground-based telescopes in the U.S. Alongside John Livingston, lead author of the study and a graduate student at the University of Tokyo, the team's combined resources led to the confirmed existence of these 44 exoplanets and described various details about them.A portion of the findings yield some surprising characteristics: "For example, four of the planets orbit their host stars in less than 24 hours," says Livingston. "In other words, a year on each of those planets is shorter than a day here on Earth." These contribute to a small but growing list of "ultrashort-period" planets, so it could turn out they're not as unusual as they might seem."It was also gratifying to verify so many small planets," continues Livingston. "Sixteen were in the same size class as Earth, one in particular turning out to be extremely small - about the size of Venus - which was a nice affirmation as it's close to the limit of what is possible to detect."The source observations for this study were made by Kepler, and they would not have happened were it not for a fault in 2013, which prevented accurate control of the space telescope."Two out of the four control-reaction wheels failed, which meant Kepler couldn't perform its original mission to stare at one specific patch of the sky," explains Professor Motohide Tamura of the University of Tokyo. "This led to its contingent mission, 'K2' - our observations came from campaign 10 of this mission. We're lucky Kepler continues to function as well as it does."The planets observed by K2 are known as transiting planets because their orbits bring them in front of their host stars, slightly reducing their brightness.However, other astrophysical phenomena can cause similar signals, so follow-up observations and detailed statistical analyses were performed to confirm the planetary nature of these signals. As part of his doctoral work, Livingston traveled to Kitt Peak observatory in the U.S. state of Arizona to obtain data from a special type of camera, known as a speckle interferometer installed on a large telescope there.These observations, along with follow-up observations from a telescope in the state of Texas, were necessary to characterize the host stars and rule out false positives. The combination of detailed analyses of data from these ground-based telescopes, K2 and Gaia enabled the precise determination of the planets' sizes and temperatures. The team's findings include 27 additional candidates that are likely to be real planets, which will be the subject of future research.Scientists hope to understand what kinds of planets might be out there, but can only draw valid conclusions if there are enough planets for robust statistical analysis. The addition of a large number of new planets, therefore, leads directly to a better theoretical understanding of solar-system formation.The planets also provide good targets for detailed individual studies to yield measurements of planetary composition, interior structure and atmospheres - in particular, the 18 planets in several multiplanet systems. "The investigation of other solar systems can help us understand how planets and even our own solar system formed," says Livingston. "The study of other worlds has much to teach us about our own."Research Report: "44 validated planets from K2 campaign 10,"
  • TESS catches a comet before starting planet hunting mission
    Mittwoch, 08.08.2018, 23:26:51 Uhr
    TESS catches a comet before starting planet hunting mission Greenbelt MD (SPX) Aug 07, 2018 -
    Before NASA's Transiting Exoplanet Survey Satellite (TESS) started science operations on July 25, 2018, the planet hunter sent back a stunning sequence of serendipitous images showing the motion of a comet.Taken over the course of 17 hours on July 25, these TESS images helped demonstrate the satellite's ability to collect a prolonged set of stable periodic images covering a broad region of the sky - all critical factors in finding transiting planets orbiting nearby stars.Over the course of these tests, TESS took images of C/2018 N1, a comet discovered by NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite on June 29. The comet, located about 29 million miles (48 million kilometers) from Earth in the southern constellation Piscis Austrinus, is seen to move across the frame from right to left as it orbits the Sun.The comet's tail, which consists of gases carried away from the comet by an outflow from the Sun called the solar wind, extends to the top of the frame and gradually pivots as the comet glides across the field of view.In addition to the comet, the images reveal a treasure trove of other astronomical activity. The stars appear to shift between white and black as a result of image processing. The shift also highlights variable stars - which change brightness either as a result of pulsation, rapid rotation, or by eclipsing binary neighbors. Asteroids in our solar system appear as small white dots moving across the field of view.Towards the end of the video, one can see a faint broad arc of light moving across the middle section of the frame from left to right. This is stray light from Mars, which is located outside the frame. The images were taken when Mars was at its brightest near opposition, or its closest distance, to Earth.These images were taken during a short period near the end of the mission's commissioning phase, prior to the start of science operations. The movie presents just a small fraction of TESS's active field of view. The team continues to fine-tune the spacecraft's performance as it searches for distant worlds.TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. Dr. George Ricker of MIT's Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission.Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA's Ames Research Center in California's Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT's Lincoln Laboratory in Lexington, Massachusetts; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.
  • VLA Detects Possible Extrasolar Planetary-Mass Magnetic Powerhouse
    Mittwoch, 08.08.2018, 23:26:51 Uhr
    VLA Detects Possible Extrasolar Planetary-Mass Magnetic Powerhouse Charlottesville VA (SPX) Aug 06, 2018 -
    Astronomers using the National Science Foundation's Karl G. Jansky Very Large Array (VLA) have made the first radio-telescope detection of a planetary-mass object beyond our Solar System. The object, about a dozen times more massive than Jupiter, is a surprisingly strong magnetic powerhouse and a "rogue," traveling through space unaccompanied by any parent star."This object is right at the boundary between a planet and a brown dwarf, or 'failed star,' and is giving us some surprises that can potentially help us understand magnetic processes on both stars and planets," said Melodie Kao, who led this study while a graduate student at Caltech, and is now a Hubble Postdoctoral Fellow at Arizona State University.Brown dwarfs are objects too massive to be considered planets, yet not massive enough to sustain nuclear fusion of hydrogen in their cores - the process that powers stars. Theorists suggested in the 1960s that such objects would exist, but the first one was not discovered until 1995. They originally were thought to not emit radio waves, but in 2001 a VLA discovery of radio flaring in one revealed strong magnetic activity.Subsequent observations showed that some brown dwarfs have strong auroras, similar to those seen in our own Solar System's giant planets. The auroras seen on Earth are caused by our planet's magnetic field interacting with the solar wind.However, solitary brown dwarfs do not have a solar wind from a nearby star to interact with. How the auroras are caused in brown dwarfs is unclear, but the scientists think one possibility is an orbiting planet or moon interacting with the brown dwarf's magnetic field, such as what happens between Jupiter and its moon Io.The strange object in the latest study, called SIMP J01365663 0933473, has a magnetic field more than 200 times stronger than Jupiter's. The object was originally detected in 2016 as one of five brown dwarfs the scientists studied with the VLA to gain new knowledge about magnetic fields and the mechanisms by which some of the coolest such objects can produce strong radio emission. Brown dwarf masses are notoriously difficult to measure, and at the time, the object was thought to be an old and much more massive brown dwarf.Last year, an independent team of scientists discovered that SIMP J01365663 0933473 was part of a very young group of stars. Its young age meant that it was in fact so much less massive that it could be a free-floating planet - only 12.7 times more massive than Jupiter, with a radius 1.22 times that of Jupiter.At 200 million years old and 20 light-years from Earth, the object has a surface temperature of about 825 degrees Celsius, or more than 1500 degrees Fahrenheit. By comparison, the Sun's surface temperature is about 5,500 degrees Celsius.The difference between a gas giant planet and a brown dwarf remains hotly debated among astronomers, but one rule of thumb that astronomers use is the mass below which deuterium fusion ceases, known as the "deuterium-burning limit", around 13 Jupiter masses.Simultaneously, the Caltech team that originally detected its radio emission in 2016 had observed it again in a new study at even higher radio frequencies and confirmed that its magnetic field was even stronger than first measured."When it was announced that SIMP J01365663 0933473 had a mass near the deuterium-burning limit, I had just finished analyzing its newest VLA data," said Kao.The VLA observations provided both the first radio detection and the first measurement of the magnetic field of a possible planetary mass object beyond our Solar System.Such a strong magnetic field "presents huge challenges to our understanding of the dynamo mechanism that produces the magnetic fields in brown dwarfs and exoplanets and helps drive the auroras we see," said Gregg Hallinan, of Caltech."This particular object is exciting because studying its magnetic dynamo mechanisms can give us new insights on how the same type of mechanisms can operate in extrasolar planets - planets beyond our Solar System. We think these mechanisms can work not only in brown dwarfs, but also in both gas giant and terrestrial planets," Kao said."Detecting SIMP J01365663 0933473 with the VLA through its auroral radio emission also means that we may have a new way of detecting exoplanets, including the elusive rogue ones not orbiting a parent star," Hallinan said.Kao and Hallinan worked with J. Sebastian Pineda who also was a graduate student at Caltech and is now at the University of Colorado Boulder, David Stevenson of Caltech, and Adam Burgasser of the University of California San Diego. They are reporting their findings in the Astrophysical Journal.The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
  • Tiny tunnels inside garnets appear to be the result of boring microorganisms
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    Tiny tunnels inside garnets appear to be the result of boring microorganisms Washington DC (SPX) Aug 09, 2018 -
    Complex systems of microscopic tunnels found inside garnet crystals from Thailand are most likely the result of microorganisms making their homes inside these minerals, according to a study published August 8, 2018 in the open-access journal PLOS ONE by Magnus Ivarsson of the University of Southern Denmark and colleagues.Endolithic organisms are those that live inside a substrate, be it mineral, wood, bone, or some other material. Some microbes move into pre-existing cavities while others dig their own way in, but this behavior is unexpected in highly resistant minerals like garnet.In this study, Ivarsson and colleagues examined the structure and content of intricately branching tunnels inside garnet crystals from river sediments and soils in Thailand to determine whether they were formed by abiotic or biotic processes.Chemical analysis of the tunnels found lingering organic compounds and filament-like structures reminiscent of bacteria and fungi, strongly suggesting that microbes once lived inside. Whether or not these organisms excavated the tunnels is less clear.The shape of the tunnels, examined under microscopy, doesn't completely rule out an abiotic origin, but certain features characteristic of endolithic lairs, such as anastomoses (connecting passages between adjacent tunnels) suggest the tunnels were at least partially formed by endolithic microbes.These tunnels were originally noted because they "significantly decrease the quality and value of the garnets as gems," but this study has shown that they also represent a previously unrecognized habitat for endolithic organisms.In iron-poor sediments like those studied here, garnets represent a rare source of iron for iron-oxidizing microbes, but confirming the identity of the tunnel-borers will require observations of live organisms in a laboratory setting.Ivarsson notes: "The reported tunnel system in garnets represents a new endolithic habitat in a hard silicate mineral otherwise known to be resistant to abrasion and chemical attack."Research Report: Intricate tunnels in garnets from soils and river sediments in Thailand - Possible endolithic microborings. PLoS ONE 13(8): e0200351.
  • Exoplanets where life could develop as on Earth
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    Exoplanets where life could develop as on Earth Cambridge UK (SPX) Aug 03, 2018 -
    Scientists have identified a group of planets outside our solar system where the same chemical conditions that may have led to life on Earth exist.The researchers, from the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology (MRC LMB), found that the chances for life to develop on the surface of a rocky planet like Earth are connected to the type and strength of light given off by its host star.Their study, published in the journal Science Advances, proposes that stars which give off sufficient ultraviolet (UV) light could kick-start life on their orbiting planets in the same way it likely developed on Earth, where the UV light powers a series of chemical reactions that produce the building blocks of life.The researchers have identified a range of planets where the UV light from their host star is sufficient to allow these chemical reactions to take place, and that lie within the habitable range where liquid water can exist on the planet's surface."This work allows us to narrow down the best places to search for life," said Dr. Paul Rimmer, a postdoctoral researcher with a joint affiliation at Cambridge's Cavendish Laboratory and the MRC LMB, and the paper's first author. "It brings us just a little bit closer to addressing the question of whether we are alone in the universe."The new paper is the result of an ongoing collaboration between the Cavendish Laboratory and the MRC LMB, bringing together organic chemistry and exoplanet research. It builds on the work of Professor John Sutherland, a co-author on the current paper, who studies the chemical origin of life on Earth.In a paper published in 2015, Professor Sutherland's group at the MRC LMB proposed that cyanide, although a deadly poison, was in fact a key ingredient in the primordial soup from which all life on Earth originated.In this hypothesis, carbon from meteorites that slammed into the young Earth interacted with nitrogen in the atmosphere to form hydrogen cyanide. The hydrogen cyanide rained to the surface, where it interacted with other elements in various ways, powered by the UV light from the Sun. The chemicals produced from these interactions generated the building blocks of RNA, the close relative of DNA which most biologists believe was the first molecule of life to carry information.In the laboratory, Sutherland's group recreated these chemical reactions under UV lamps, and generated the precursors to lipids, amino acids and nucleotides, all of which are essential components of living cells."I came across these earlier experiments, and as an astronomer, my first question is always what kind of light are you using, which as chemists they hadn't really thought about," said Rimmer. "I started out measuring the number of photons emitted by their lamps, and then realised that comparing this light to the light of different stars was a straightforward next step."The two groups performed a series of laboratory experiments to measure how quickly the building blocks of life can be formed from hydrogen cyanide and hydrogen sulphite ions in water when exposed to UV light. They then performed the same experiment in the absence of light."There is chemistry that happens in the dark: it's slower than the chemistry that happens in the light, but it's there," said senior author Professor Didier Queloz, also from the Cavendish Laboratory. "We wanted to see how much light it would take for the light chemistry to win out over the dark chemistry."The same experiment run in the dark with the hydrogen cyanide and the hydrogen sulphite resulted in an inert compound which could not be used to form the building blocks of life, while the experiment performed under the lights did result in the necessary building blocks.The researchers then compared the light chemistry to the dark chemistry against the UV light of different stars. They plotted the amount of UV light available to planets in orbit around these stars to determine where the chemistry could be activated.They found that stars around the same temperature as our Sun emitted enough light for the building blocks of life to have formed on the surfaces of their planets. Cool stars, on the other hand, do not produce enough light for these building blocks to be formed, except if they have frequent powerful solar flares to jolt the chemistry forward step by step. Planets that both receive enough light to activate the chemistry and could have liquid water on their surfaces reside in what the researchers have called the abiogenesis zone.Among the known exoplanets which reside in the abiogenesis zone are several planets detected by the Kepler telescope, including Kepler 452b, a planet that has been nicknamed Earth's 'cousin,' although it is too far away to probe with current technology. Next-generation telescopes, such as NASA's TESS and James Webb telescopes, will hopefully be able to identify and potentially characterise many more planets that lie within the abiogenesis zone.Of course, it is also possible that if there is life on other planets, that it has or will develop in a totally different way than it did on Earth."I'm not sure how contingent life is, but given that we only have one example so far, it makes sense to look for places that are most like us," said Rimmer. "There's an important distinction between what is necessary and what is sufficient. The building blocks are necessary, but they may not be sufficient: it's possible you could mix them for billions of years and nothing happens. But you want to at least look at the places where the necessary things exist."According to recent estimates, there are as many as 700 million trillion terrestrial planets in the observable universe. "Getting some idea of what fraction have been, or might be, primed for life fascinates me," said Sutherland. "Of course, being primed for life is not everything and we still don't know how likely the origin of life is, even given favourable circumstances - if it's really unlikely then we might be alone, but if not, we may have company."Research Report: "The Origin of RNA Precursors on Exoplanets," Paul B. Rimmer et al., 2018 Aug. 1, Science Advances
  • Exoplanet detectives create reference catalog of spectra and geometric albedos
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    Exoplanet detectives create reference catalog of spectra and geometric albedos Ithaca NY (SPX) Aug 02, 2018 -
    Earthbound detectives rely on fingerprints to solve their cases; now astronomers can do the same, using "light-fingerprints" instead of skin grooves to uncover the mysteries of exoplanets.Cornell University researchers have created a reference catalog using calibrated spectra and geometric albedos - the light reflected by a surface - of 19 of the most diverse bodies in our solar system. These include all eight planets, from rocky to gaseous; nine moons, from frozen to lava spewing; and two dwarf planets, one in the asteroid belt - Ceres - and one in the Kuiper belt - Pluto.By comparing observed spectra and albedos of exoplanets to this catalog of our own home planetary system, scientists will be able to characterize them in reference to the wide range of icy, rocky and gaseous worlds in our home system."A Catalog of Spectra, Albedos and Colors of Solar System Bodies for Exoplanet Comparison" was published online in Astrobiology and will be featured on the print edition's cover in December."We use our own solar system and all we know about its incredible diversity of fascinating worlds as our Rosetta Stone," said co-author Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute. "With this catalog of light-fingerprints, we will be able to compare new observations of exoplanets to objects in our own solar system - including the gaseous worlds of Jupiter and Saturn, the icy worlds of Europa, the volcanic world of Io and our own life-filled planet."The catalog, freely available on the Carl Sagan Institute website [http://carlsaganinstitute.org/data/spectra-and-albedos-of-solar-system-bodies], includes high- and low-resolution versions of the data, which shows astronomers the influence of spectral resolution on an object's identification. In addition, the catalog offers examples of how the colors of the 19 solar system models would change if they were orbiting stars other than our Sun."Planetary science broke new ground in the '70s and '80s with spectral measurements for solar system bodies. Exoplanet science will see a similar renaissance in the near future," said Jack Madden, doctoral candidate at the Carl Sagan Institute and lead author of the study."The technology to directly collect the light from Earth-sized planets around other stars is currently in a clean room waiting to be assembled and trained on the right target. With the upcoming launch of the James Webb Space Telescope and the current construction of large ground-based telescopes such as the Giant Magellan Telescope and the Extremely Large Telescope, we are entering a new age of observational ability, so we need a reference catalog of all the planets and moons we already know, to compare these new exoplanet spectra to."The catalog will enable scientists to prioritize time-intensive, high-resolution observations of extrasolar planets and moons. It also offers insights into what kind of worlds won't be so easy to categorize without high-resolution spectra.For example, Venus is a rocky planet, but because sunlight reflects from its dense carbon dioxide atmosphere rather than its rocky surface, the colors astronomers observe from such a planet are similar to those of an icy world. On the outer edge of the habitable zone, rocky exoplanets are likely to have dense atmospheres like Venus. Such worlds will require long observations to characterize correctly."Examining our solar system from the vantage point of a distant observer is an illuminating exercise," said Madden."By unraveling the mysteries of the objects in our own solar system we can glimpse the secrets of these new worlds we are finding," said Kaltenegger.Research Report: "A Catalog of Spectra, Albedos, and Colors of Solar System Bodies for Exoplanet Comparison," J. H. Madden and Lisa Kaltenegger, 2018 July 31, Astrobiology
  • NASA's TESS spacecraft starts science operations
    Mittwoch, 08.08.2018, 23:26:51 Uhr
    NASA's TESS spacecraft starts science operations Washington DC (SPX) Jul 30, 2018 -
    NASA's Transiting Exoplanet Survey Satellite has started its search for planets around nearby stars, officially beginning science operations on July 25, 2018.TESS is expected to transmit its first series of science data back to Earth in August, and thereafter periodically every 13.5 days, once per orbit, as the spacecraft makes it closest approach to Earth. The TESS Science Team will begin searching the data for new planets immediately after the first series arrives."I'm thrilled that our new planet hunter mission is ready to start scouring our solar system's neighborhood for new worlds," said Paul Hertz, NASA Astrophysics division director at Headquarters, Washington."Now that we know there are more planets than stars in our universe, I look forward to the strange, fantastic worlds we're bound to discover."TESS is NASA's latest satellite to search for planets outside our solar system, known as exoplanets. The mission will spend the next two years monitoring the nearest and brightest stars for periodic dips in their light.These events, called transits, suggest that a planet may be passing in front of its star. TESS is expected to find thousands of planets using this method, some of which could potentially support life.
  • How Can You Tell If That ET Story Is Real
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    How Can You Tell If That ET Story Is Real Mountain View CA (SPX) Jul 25, 2018 -
    What are the consequences for the human race if we encountered extraterrestrial intelligence? If you see a story about aliens on TV or online, how excited should you be? A new study, published in the International Journal of Astrobiology, revamps a long-used tool for classifying potential signals from extraterrestrial intelligence, making it fit for the modern world of news and social media.First developed in 2001, the Rio Scale is a tool used by astronomers searching for extraterrestrial intelligence (ETI) to help communicate to the public 'how excited' they should be about what has been observed.The scale measures the consequences for humans if the signal is from aliens, as well as the probability that the signal really is from aliens, and not a natural phenomenon or human-made. The scale gives a score between zero and ten, so that the public can quickly see how important a signal really is."The whole world knows about the Richter Scale for quantifying the severity of an earthquake; that number is reported immediately following a quake and subsequently refined as more data are consolidated," said Jill Tarter, co-founder of the SETI Institute."The SETI community is attempting to create a scale that can accompany reports of any claims of the detection of extraterrestrial intelligence and be refined over time as more data become available."This scale should convey both the significance and credibility of the claimed detection. Rio 2.0 is an attempt to update the scale to make it more useful and compatible with current modes of information dissemination, as well as providing means for the public to become familiar with the scale."There have been many dubious signals reported as 'aliens' in recent years, and learning the truth about these stories is increasingly difficult. As such, an updated Rio Scale is required.The new study, led by Dr. Duncan Forgan at the University's Centre for Exoplanet Science, highlights the changing nature of news media, the growth of 24-hour news and the new landscape of social media. Coupled with an increase in efforts to detect ETI by teams around the world, the Rio Scale is needed more than ever, and it must remain relevant when communicating to the public about 'alien signals.'The international team of researchers' revision of the Rio Scale (Rio 2.0) aims to bring consensus across academic disciplines, when classifying signals potentially indicating the existence of advanced extraterrestrial life.Rio 2.0 can quickly calibrate the public expectations of a reported signal, and educate them as to how SETI scientists actually evaluate a signal, from its initial detection through the various verification stages needed to determine if a signal is credibly from ETI.Key to the research is also the development of a single set of consistent terminology for discussing signals, both among researchers and in the media.The team has published an online Rio Scale Calculator, an interactive tool for scientists and science communicators to evaluate signals and give advice on how to use it for better reporting of ETI in the media.Lead researcher, Dr. Duncan Forgan, Centre for Exoplanet Science, University of St. Andrews, said: "It's absolutely crucial that when we talk about something so hugely significant as the discovery of intelligent life beyond the Earth, we do it clearly and carefully."Having Rio 2.0 allows us to rank a signal quickly in a way that the general public can easily understand, and helps us keep their trust in a world filled with fake news."The new Rio Scale has now been submitted to the International Academy of Astronautics Permanent Committee on SETI for official ratification.Research Report: "Rio 2.0: Revising the Rio Scale for SETI Detections," Duncan Forgan et al., 2018 July 24, International Journal of Astrobiology
  • WSU researcher sees possibility of moon life
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    WSU researcher sees possibility of moon life Pullman WA (SPX) Jul 24, 2018 -
    While the Moon is uninhabitable today, there could have been life on its surface in the distant past.In fact, there may have been two early windows of habitability for Earth's Moon, according to a study online in the journal Astrobiology by Dirk Schulze-Makuch, an astrobiologist at Washington State University.Schulze-Makuch and Ian Crawford, a professor of planetary science and astrobiology at the University of London, say conditions on the lunar surface were sufficient to support simple lifeforms shortly after the Moon formed from a debris disk 4 billion years ago and again during a peak in lunar volcanic activity around 3.5 billion years ago.During both periods, planetary scientists think the Moon was spewing out large quantities of superheated volatile gases, including water vapor, from its interior.Schulze-Makuch and Crawford write that this outgassing could have formed pools of liquid water on the lunar surface and an atmosphere dense enough to keep it there for millions of years."If liquid water and a significant atmosphere were present on the early Moon for long periods of time, we think the lunar surface would have been at least transiently habitable," Schulze-Makuch said.Ingredients for life
    Schulze-Makuch and Crawford's work draws on results from recent space missions and sensitive analyses of lunar rock and soil samples that show the Moon is not as dry as previously thought.In 2009 and 2010, an international team of scientists discovered hundreds of millions of metric tons of water ice on the Moon. Additionally, there is strong evidence of a large amount of water in the lunar mantle that is thought to have been deposited very early on in the Moon's formation.The early Moon is also likely to have been protected by a magnetic field that could have shielded lifeforms on the surface from deadly solar winds.Space-travelling microbes
    Life on the Moon could have originated much as it did on Earth but the more likely scenario is that it would have been brought in by a meteorite, Schulze-Makuch said.The earliest evidence for life on Earth comes from fossilized cyanobacteria that are between 3.5 and 3.8 billion years old. During this time, the solar system was dominated by frequent and giant meteorite impacts. It is possible that meteorites containing simple organisms like cyanobacteria could have been blasted off the surface of the Earth and landed on the Moon."It looks very much like the Moon was habitable at this time," Schulze-Makuch said. "There could have actually been microbes thriving in water pools on the Moon until the surface became dry and dead."Lunar simulations
    Schulze-Makuch acknowledges that determining if life arose on the Moon or was transported from elsewhere "can only be addressed by an aggressive future program of lunar exploration."One promising line of inquiry for any future space missions would be to obtain samples from deposits from the period of heightened volcanic activity to see if they contained water or other possible markers of life.In addition, experiments could be conducted in simulated lunar environments on Earth and on the International Space Station to see if microorganisms can survive under the environmental conditions predicted to have existed on the early Moon.Research paper
  • Glowing bacteria on deep-sea fish shed light on evolution, 'third type' of symbiosis
    Mittwoch, 08.08.2018, 23:26:51 Uhr
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    Glowing bacteria on deep-sea fish shed light on evolution, 'third type' of symbiosis Ithaca NY (SPX) Jul 19, 2018 -
    You may recognize the anglerfish from its dramatic appearance in the hit animated film Finding Nemo, as it was very nearly the demise of clownfish Marlin and blue-tang fish Dory. It lives most of its life in total darkness more than 1,000 meters below the ocean surface.Female anglerfish sport a glowing lure on top of their foreheads, basically a pole with a light bulb on its end, where bioluminescent bacteria live. The light-emitting lure attracts both prey and potential mates to the fish.Despite its recent fame, little is known about anglerfish and their symbiotic relationship with these brilliant bacteria, because the fish are difficult to acquire and study.For the first time, scientists have sequenced and analyzed the genomes of bacteria that live in anglerfish bulbs. The bacteria were taken from fish specimens collected in the Gulf of Mexico.The researchers report their findings in a new study, published in the journal mBio. The analysis revealed that the bacteria have lost some of the genes that are needed to live freely in the water. That's because the fish and bacteria developed a tight, mutually beneficial relationship, where the bacteria generate light while the fish supplies nutrients to the microbe."What's particularly interesting about this specific example is that we see evidence that this evolution is still underway, even though the fish themselves evolved about 100 million years ago," said Tory Hendry, assistant professor of microbiology at Cornell University and the paper's lead author. "The bacteria are still losing genes, and it's unclear why."Most of the known symbiotic relationships between organisms and bacteria are between either a host and free-living bacteria that don't evolve to maintain a symbiosis, or a host and intracellular bacteria that live inside the host's cells and undergo huge reductions in their genomes through evolution.The bacteria inside the bulb in anglerfish represents a third type of symbiosis, where preliminary data suggest these bacteria may move from the anglerfish bulb to the water. "It's a new paradigm in our understanding of symbiosis in general; this is a third type of situation where the bacteria are not actually stuck with their host but they are undergoing evolution," Hendry said.Genetic sequencing showed that the genomes of these anglerfish bioluminescent bacteria are 50 percent reduced compared with their free-swimming relatives. The bacteria have lost most of the genes associated with making amino acids and breaking down nutrients other than glucose, suggesting the fish may be supplying the bacteria with nutrients and amino acids.At the same time, the bacteria have retained some genes that are useful in water outside the host. They have full pathways to make a flagellum, a corkscrew tail for moving in water.The bacteria had lost most of the genes involved in sensing chemical cues in the environment that may lead to food or other useful compounds, though a few remained, leaving a subset of chemicals they still respond to. "They were pared down to something they cared about," Hendry said.Research paper
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