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  • richardmitnick 10:02 am on May 13, 2019 Permalink | Reply
    Tags: , , Many Worlds, NASA’s Astrobiology Program, NExSS 2.0, Nexus for Exoplanet System Science or “NExSS”, Signatures of life on distant planets, Teams from seventeen academic and NASA centers   

    From Many Worlds: “NExSS 2.0” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    May 13, 2019
    Marc Kaufman

    1
    Finding new worlds can be an individual effort, a team effort, an institutional effort. The same can be said for characterizing exoplanets and understanding how they are affected by their suns and other planets in their solar systems. When it comes to the search for possible life on exoplanets, the questions and challenges are too great for anything but a community. NASA’s NExSS initiative has been an effort to help organize, cross-fertilize and promote that community. This artist’s concept Kepler-47, the first two-star systems with multiple planets orbiting the two suns, suggests just how difficult the road ahead will be. ( NASA/JPL-Caltech/T. Pyle)

    The Nexus for Exoplanet System Science, or “NExSS,” began four years ago as a NASA initiative to bring together a wide range of scientists involved generally in the search for life on planets outside our solar system.

    With teams from seventeen academic and NASA centers, NExSS was founded on the conviction that this search needed scientists from a range of disciplines working in collaboration to address the basic questions of the fast-growing field.

    Among the key goals: to investigate just how different, or how similar, different exoplanets are from each other; to determine what components are present on particular exoplanets and especially in their atmospheres (if they have one); to learn how the stars and neighboring exoplanets interact to support (or not support) the potential of life; to better understand how the initial formation of planets affects habitability, and what role climate plays as well.

    Then there’s the question that all the others feed in to: what might scientists look for in terms of signatures of life on distant planets?

    Not questions that can be answered alone by the often “stove-piped” science disciplines — where a scientist knows his or her astrophysics or geology or geochemistry very well, but is uncomfortable and unschooled in how other disciplines might be essential to understanding the big questions of exoplanets.

    2
    The original NExSS team was selected from groups that had won NASA grants and might want to collaborate with other scientists with overlapping interests and goals but often from different disciplines. (NASA)

    The original idea for this kind of interdisciplinary group came out of NASA’s Astrobiology Program, and especially from NASA astrobiology director Mary Voytek and colleague Shawn Domogal-Goldman. It was something of a gamble, since scientists who joined would essentially volunteer their time and work and would be asked to collaborate with other scientists in often new ways.

    But over the past four years NExSS has proven itself to be very active and useful in terms of laying out strategies for tackling the biggest questions in the field of exoplanets and whether they might harbor life. In two major reports last year, the private, congressionally-mandated National Academies of Sciences, Engineering and Medicine held up NExSS as a successful model for moving the science forward.

    One of the study co-chairs, David Charbonneau of Harvard University, said after the release of the study that the “promise of NExSS is tremendous…We really want that idea to grow and have a huge impact.”

    3
    This major report from the National Academy of Sciences last year endorsed NExSS as a program that substantially aided the exoplanet community. The report recommended that the organization be expanded. (NAS)

    So with that kind of affirmation, it was hardly surprising that the first gathering of a newly constituted NExSS at the University of California, Santa Cruz featured 34 teams, double the original 17. (The team members, both new and original, are here.)

    As explained at the opening of the gathering by Voytek and others, the NExSS approach is all about creating, expanding and promoting the fast-growing fields of exoplanet habitability and astrobiology more generally.

    “The original NExSS members were in service to all of you,” she told the group. “They provided the opportunity to help your community to push questions further and also to get NASA headquarters to give some necessary attention to what you are doing.”

    And in many ways they succeeded. The NExSS teams may not have gotten funded additionally for their work, but the group’s rising profile created important advisory opportunities for participants.

    From the first NExSS groups, for instance, scientists were selected for leadership roles in the main exoplanet science group and several for science and technology definition teams. These groups established by NASA are putting together four proposals for a grand observatory for the 2030s — a hoped-for successor to the Hubble Space Telescope and the James Webb Space Telescope.

    NExSS members also were called on to organize in-depth workshops on subjects ranging from defining and interpreting biosignatures on distant planets, to the centrality of exoplanet interiors and most recently to what signs of advanced technological civilizations might be detectable. Major white papers were generally written, submitted and published in journals following these NExSS workshops.

    “I think putting together NExSS is most successful thing I’ve done in my career in NASA,” said Voytek who, in her decade-plus at the agency, has worked to change attitudes about astrobiology and interdisciplinary work. “I’m proud of what you did and we did.”

    What’s more, as Voytek explained at the beginning of the meeting, the NExSS approach will spread with the creation of four new networking groups based on the model of NExSS.

    They will use the same cross-disciplinary, get-to-know-your-fellow scientists approach to jump-start collaborations and cross-fertilizing in other aspects of the search for life beyond Earth, as well as the effort to understand how life on Earth (and potentially elsewhere) might have started and grown more complex.

    (The four, below, focus on planetary chemistry before life, on biosignatures, on the transition from early single cell organisms to more complex ones, and on what can be learned from ocean worlds.)

    This expansion, which will be part of a reorganization of NASA’s astrobiology program, will change the way that science teams will be funded and also, as Voytek put it, would “democratize” the process that NExSS began. The original program had selected many of its principal investigators from large teams and organizations, but the expanded NExSS and the four other groups to come will be more widely open to teams and individuals from smaller institutions who are earlier in their careers.

    This is important, Voytek and other NExSS organizers said, because the NExSS approach allows scientists to network in ways that create science opportunities, as well as those avenues into the major prioritizing organizations in their exoplanet/astrobiology community writ large.

    3

    One value of this approach can be seen in the person of planetary scientist Sarah Morrison, a postdoc at the large Pennsylvania State University exoplanet program who has been hired to teach at the much smaller Missouri State University program.

    3

    She is a co-principal investigator on one of two NExSS teams at Penn State and was at last week’s Santa Cruz meeting in that capacity.

    Her research focuses on protoplanetary disks and planet formation within them. In particular, she studies the many different types of interactions — collisions, migrations, atmosphere losses — that forming planets can have within their natal disks. She is also intrigued by solar systems where the planets orbit in resonance to each other.

    These factors, and many others, have implications for the composition of planets and then for the possibility of life starting on them. Factors such as the eccentricity of a planet’s orbit or where it was formed within the disk can make a planet a good candidate for habitability or one where life is impossible.

    For Morrison, NExSS is an avenue for keeping her research vibrant.

    “I’m going to a smaller institution, with not so many people doing exoplanets,” she told me. “For me to remain active in the field and work, and to have the collaborators I need to open possibilities for students working with me, this type of network can be very important – on the research side and education side.”

    She said that it isn’t always easy to find scientists whose work overlaps with hers, but that at the NExSS meeting it was easy.

    “I can definitely see projects down the line as a result of conversations I had with those folks,” she said. “And developing collaborations now is very important to me.”

    As described by Voytek and other NExSS leaders, another major focus of the group has been to encourage NASA headquarters to embrace some of the interdisciplinary approach they practice and are convinced is necessary.

    This is part of a much longer effort by Voytek and other to include the search for life beyond Earth in the missions large and small that NASA develops. There was certainly resistance at times, but the agency has, in the past decade, made that search an increasingly central NASA goal.

    As described by NExSS leader (or “Jedi”) Dawn Gelino, deputy director of the agency’s Exoplanet Science Institute, NASA headquarters has responded in other ways as well, and in recent months made two of its major research grant programs interdivisional.

    That means scientists from quite different but nonetheless related disciplines can — for the first time — together propose projects for funding by those NASA programs. Thomas Zurbuchen, NASA’s associate administrator of the Science Mission Directorate, has been forceful in his support for this kind of approach.

    “As a result of NExSS, we are definitely making a difference at headquarters in terms of the structure of teams responding to calls for proposals,” Gelino said.

    A NExSS interdisciplinary approach is not for everyone, and some question its value. Many researchers would prefer to spend their time at the telescope, in the lab, with their modeling computers, writing papers — with laser focus on their areas of expertise. NExSS leaders regularly make the point that those decisions are understood and perfectly fine.

    But especially in inherently interdisciplinary fields such as exoplanets and astrobiology, the pool of scientists willing to pitch in to advance the community appears to be large and has proven go be quite useful.

    (Since I am writing about NExSS, I want to be clear in saying that the program helps support Many Worlds. A second column about NExSS brain-storming about the future of exoplanet and habitability studies will be coming soon.)

    See the full article here .


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    Please help promote STEM in your local schools.

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    About Many Worlds
    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:37 am on March 4, 2019 Permalink | Reply
    Tags: "How Creatures End Up Miles Below the Surface of Earth and Maybe Mars Too", An inevitable and most interesting question that arises is this: If there was robust and adaptable life on early Mars might it have been transported underground in water too?, At the Kopanang mine they had found the roundworm Poikilolaimus oxycercusin in water about a mile underground. What appeared to be the same nematode was also collected from the the Vaal river a few mi, “M. parvella does not have a hibernation stage and cannot survive in fresh water thus it must have been and must be in brackish water all the time” Borgonie said. “The question is did this happe, , , Ecosystems can survive in scalding temperatures in the absence of sunlight at high pressure and without oxygen. Yet they have been found as far down as almost three miles below the surface though in f, H. mephisto, Many Worlds, , Recent reports of another nematode species unaffiliated with South African mines suggests just how robust and adaptable individuals can be — in this case regarding deep freeze hibernation., Round worm Poikilolaimus oxycercus, Salese and colleagues explored 24 deep enclosed craters in the northern hemisphere of Mars with floors lying roughly 4000 meters (2.5 miles) below Martian ‘sea level’ (a level that given the plane, Some potential early Martian life could have migrated into the more protected depths is often discussed as a plausible if at this point untestable possibility   

    From Many Worlds: “How Creatures End Up Miles Below the Surface of Earth, and Maybe Mars Too” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2019-03-04
    Marc Kaufman

    1
    Poikilolaimus oxycercus is a microscopic nematode, or roundworm, found alive and well more than a mile below the surface in South Africa, where its ancestors had lived for hundreds or thousands of years. (Gaetan Borgonie)

    When scientists speculate about possible life on Mars, they generally speak of microbial or other simple creatures living deep below the irradiated and desiccated surface. While Mars long ago had a substantial period that was wetter and warmer when it also had a far more protective atmosphere, the surface now is considered to be lethal.

    But the suggestion that some potential early Martian life could have migrated into the more protected depths is often discussed as a plausible, if at this point untestable possibility. In this scenario, some of that primitive subsurface life might even have survived the eons in their buried, and protected, environments.

    This thinking has gotten some support in the past decade with the discovery of bacteria and nematodes (roundworms) found as far down as three miles below the surface of South Africa, in water dated as being many thousands or millions years old. The lifeforms have been discovered by a team that has regularly gone down into the nation’s super-hot gold and platinum mines to search for life coming out of boreholes in the rock face of deep mine tunnels.

    2
    Borgonie setting up a water collector for a borehole at the Driefontein mine in the Witwatersrand Basin of South Africa. (Courtesy of Borgonie)

    Now a new paper [below] describes not only the discovery of additional deep subsurface life, but also tries to explain how the distant ancestors of the worms and bacteria and algae might have gotten there.

    Their conclusion: many were pulled down when fractures opened in the aftermath of earthquakes and other seismic events. While many lifeforms were swept down, only a small percentage were able to adapt, evolve and thus survive.

    The is how Gaetan Borgonie, lead author of the paper in Scientific Reports, explained it to me via email:

    “After the discovery of multicellular animals in the deep subsurface up to 3.8 km (2.5 miles) in South Africa everyone was baffled and asked the question how did they get that deep? This question more or less haunted us for more than a decade as we were unable to get our head around it.

    “However during the decade as we made more observations of multicellular organisms we captured in borehole water we found that these were nearly all animals associated with fresh water and not the soil. This indicated the passage to the deep was from a fresh water source on the surface and that animals did not crawl all the way down through the topsoil over millennia.”

    This makes sense because the deepest soil inhabitants live at about six feet below the surface, said Borgonie, formerly of the University of Ghent in Belgium and now with ELi, a Belgian nonprofit that studies extreme life. So another route to their deep subterranean homes was necessary.

    3
    One of six hibernating nematodes found in biofilms from a borehole in the Kopanang mine. Four of the six in this “dauer” or survival state were taken, placed in a petri dish and came back to active life. Several were mated with worms of the same Poikilolaimus oxycercus species and the offspring survived. (Gaetan Borgonie)

    Borgonie and his team conducted a variety of tests — seismic, geological, genetic — but one stands out as most conclusive.

    At the Kopanang mine, they had found the roundworm Poikilolaimus oxycercusin in water about a mile underground. What appeared to be the same nematode was also collected from the the Vaal river, a few miles from the mine.

    The two appeared to be genetically similar, but the best test was to see if they could successfully reproduce. And the answer was that they could.

    It was a smoking gun, though not necessarily a common one. Nematodes from other surfaces and subsurfaces were placed together and were not able to produce young that survived. As explained in the Scientific Reports paper, this may be a function of the once companionable subsurface nematodes having adapted to their environment in ways that broke their connections with surface nematodes of the same species.

    While nematodes can hibernate for long periods in what is called their dauer stage, when they wake up they survive for only 20 to 30 days. Their lines, however, can last in the subsurface for those very long periods.

    4
    Tunnels in South Africa’s Beatrix mine close to where H. mephisto was found. The deeper one goes in the mine, the hotter it gets. And yet life survives in the fracture water and other often tiny pockets of liquid. (Gaetan Borgonie)

    The nematodes collected and tested for this most recent article were but a small part of the zoo of creatures that have been collected from deep underground in South Africa’s Witwatersrand Basin. There was also algae, fungi, bacteria, a crustaceans and even a few insects, the paper reports. The bacteria is important for the nematodes in particular because they are a food source.

    These ecosystems survive in scalding temperatures, in the absence of sunlight, at high pressure and without oxygen. Yet they have been found as far down as almost three miles below the surface, though in far more isolated conditions at that depth.

    5
    Borgonie with Esta van Heerden, who helped gain access to South African mines for researchers including Borgonie and Princeton University geomicrobiologist Tullis Onstott more than a decade ago is part of their research team. She is founder of the mine water remediation company iwatersolutions and was formerly a professor with the University of the Free State in Bloemfontein, where she was a specialist in extremophiles. (Courtesy of Borgonie)

    The age of that life is difficult to determine. While methods exist to determine the age of the fracture water, scientists cannot definitively say when the lifeforms arrived. Still, Borgonie reports that the worms found at the Kopanang mine had been present for between 3,000 and 12,000 years, or rather their ancestors had been there.

    Borgonie and his colleagues had earlier discovered the first multicellular creature at great depth, Halicephalobus mephisto, in mine fracture water .6 to 3 miles down. That discovery, announced in 2011, helped establish that the deep subsurface was more able to support life, even complex life, than expected.

    Often the creatures were living in biofilms, loose collections of bacteria and other life held together in the water by secretions that encase them.

    Another aspect of the deep subsurface nematode story involves specimen found in salty stalactites at the Beatrix gold mine. The worms identified, Monhystrella parvella, are associated with salty environments and so the group inferred that the water and creatures may have come from a sea. There were such seas in what is now South Africa, but it was very long ago.

    “M. parvella does not have a hibernation stage and cannot survive in fresh water, thus it must have been and must be in brackish water all the time,” Borgonie said. “The question is did this happen long ago when that area of South Africa was covered by a sea or did it happen via the salt pans surrounding the Beatrix mine?

    “There is no way to know for now. But the fact is and remains that you have a worm in the subsurface in the middle of South Africa that can only survive in salty water.”

    Recent reports of another nematode species, unaffiliated with South African mines, suggests just how robust and adaptable individuals can be — in this case regarding deep freeze hibernation.

    The longest recorded nematode hibernation was 39 years until Russian scientists announced the discovery of frozen nematodes in deep Siberian permafrost. The worms had been asleep for 42,000 and 34,000 years respectively. A Science Alert article raises the possibility of contamination as an issue, but the scientists maintain they took all possible precautions and are convinced the frozen hibernations were as recorded.

    6
    Using an electron microscope, we see the inside of a stalactite in the Beatrix gold mine, about 1 mile below the surface. The nematodes are of the species Monhystrella parvella. (Gaetan Borgonie)

    That the South African deep subsurface life appears now to have come from the surface — via seismic fractures that could bring rushes or trickles of water filled with life many miles down — does have possible implications for Mars. While no signs of early life on Mars have been discovered, research in recent years has proven that the planet once had substantial water and warmer temperatures. In other words, conditions that might be hospitable to life.

    That theory of a once quite watery Mars was taken a significant step further last week in an article in the Journal of Geophysical Research — Planets , which found evidence of an earlier planet-wide groundwater system. Such a system had been predicted before by models, but now there was significant hard evidence that it had indeed existed.

    “Early Mars was a watery world, but as the planet’s climate changed this water retreated below the surface to form pools and ‘groundwater’,” says lead author Francesco Salese of Utrecht University, the Netherlands.

    “We traced this water in our study — as its scale and role is a matter of debate — and we found the first geological evidence of a planet-wide groundwater system on Mars.”

    Salese and colleagues explored 24 deep, enclosed craters in the northern hemisphere of Mars, with floors lying roughly 4000 meters (2.5 miles) below Martian ‘sea level’ (a level that, given the planet’s lack of seas, is arbitrarily defined on Mars based on elevation and atmospheric pressure).

    The scientists found features on the floors of these craters that could only have formed in the presence of water. Many craters contain multiple features, all at depths of 2.5 to 3 miles – indicating that these craters once contained pools and flows of water that changed and receded over time.

    7
    Researchers said flow channels, pool-shaped valleys and fan-shaped sediment deposits seen in dozens of kilometers-deep craters in Mars’ northern hemisphere would have needed water to form. (European Space Agency)

    So an inevitable and most interesting question that arises is this: If there was robust and adaptable life on early Mars, might it have been transported underground in water too?

    The planet does have seismic activity — some are called Marsquakes — that can open fractures. It seems plausible that if life existed in water on the Martian surface, it would have flowed or trickled down fractures and other porous features to substantial depths.

    Given this hypothetical, many would have died but some may have lived and adapted. Rather like what can be seen on Earth in the South African mines.

    With this possibility in mind, the Borgonie paper recommends that the presence of surface fractures be kept in mind when landing sites are chosen on other planets or moons.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds
    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 1:28 pm on January 2, 2019 Permalink | Reply
    Tags: , , , , Many Worlds, Weird Planets   

    From Many Worlds: “Weird Planets” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2019-01-02
    Marc Kaufman

    1
    Artist rendering of an “eyeball world,” where one side of a tidally locked planet is turning hot and the back side is frozen cold. Somewhat like our moon, and very common in the cosmos. But unlike the moon, might some of the the planets be habitable at the edges? (NASA/JPL-Caltech)

    The very first planet detected outside our solar system powerfully made clear that our prior understanding of what planets and solar systems could be like was sorely mistaken.

    51 Pegasi was a Jupiter-like massive gas planet, but it was burning hot rather than freezing cold because it orbited close to its host star — circling in 4.23 days. Given the understandings of the time, its existence was essentially impossible.

    Yet there it was, introducing us to what would become a large and growing menagerie of weird planets.

    Hot Jupiters, water worlds, Tatooine planets orbiting binary stars, diamond worlds (later downgraded to carbon worlds), seven-planet solar systems with planets that all orbit closer than Mercury orbits our sun. And this is really only a brief peak at what’s out there — almost 4,000 exoplanets confirmed but billions upon billions more to find and hopefully characterize.

    I thought it might be useful — and fun — to take a look at some of the unusual planets found to learn what they tell us about planet formation, solar systems and the cosmos.

    2
    Artist’s conception of a hot Jupiter, CoRoT-2a. The first planet discovered beyond our solar system was a hot Jupiter similar to this, and this surprised astronomers and led to the view that many hot Jupiters may exist. That hypothesis has been revised as the Kepler Space Telescope found very few distant hot Jupiters and now astronomers estimate that only about 1 percent of planets are hot Jupiters. (NASA/Ames/JPL-Caltech)

    Let’s start with the seven Trappist-1 planets.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

    The first three were detected two decades ago, circling a”ultra-cool” red dwarf star a close-by 40 light years away. Observations via the Hubble Space Telescope led astronomers conclude that two of the planets did not have hydrogen-helium envelopes around them, which means the probability increased that the planets are rocky (rather than gaseous) and could potentially hold water on their surfaces.

    Then in 2016 a Belgian team, using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, found three more planets, and the solar system got named Trappist-1.

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile


    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile

    The detection of an additional outer planet was announced the next year, and in total three of the seven planets were deemed to be within the host star’s habitable zone — where liquid water could conceivably be present.

    So, we have a most interesting 7-planet solar system quite close to us, and not surprisingly it has become the focus of much observation and analysis.

    But consider this: all seven of those planets orbits Trappist-1 at a distance much smaller than from our sun to the first planet, Mercury. The furthest out planets orbits the star in 19 days, while Mercury orbits in 88 days.

    Given this proximity, then, why are the Trappist-1 planets so interesting, especially in terms of habitability? Because Trappist-1 puts out but .05 percent as much energy as our sun, and the furthest out planet (though very close to the star by the standards of our solar system) is nonetheless likely to be frozen.

    So Trappist-1 a mini-system, with seven tidally-locked (never-rotating) planets that happen to orbit in resonance to each other. Just because it is so different from our system doesn’t mean it isn’t fascinating, instructive, and even possibly the home of planets that could potentially support life.

    And since red dwarf stars are the most common type of star in the Milky way (by lot), red dwarf solar system research is an especially hot field.

    So there are mini planets and systems and massive planets in what used to be considered the impossibly wrong place. And then there are planets with highly eccentric orbits — very different from the largely circular orbits of planets in our system.

    2
    The eccentricity of HD20782b superimposed onto our circular-orbiting inner solar system planets. (Stephen Kane)

    The most extreme eccentric orbit found so far is HD 20782, measured at an eccentricity of .96. This means that the planet moves in a nearly flattened ellipse, traveling a long path far from its star and then making a fast and furious slingshot around the star at its closest approach.

    Many exoplanets have eccentricities far greater than what’s found in our solar system planets but nothing like this most unusual traveler, which has a path seemingly more like a comet than a planet.

    Researchers have concluded that the eccentricity of a planet tends to relate to the number of planets in the system, with many-planeted systems having far more regularly orbiting planets. (Ours and the Trappist-1 system are examples.)

    Unusual planets come in many other categories, such as the chemical makeup of their atmospheres, surfaces and cores. Most of the mass of stars, planets and living things consists of hydrogen and helium, with oxygen, carbon, iron and nitrogen trailing far behind.

    Solid elements are exceptionally rare in the overall scheme of the solar system. Despite being predominant on Earth, they constitute less than 1 percent of the total elements in the solar system, primarily because the amount of gas in the sun and gas giants is so great. What is generally considered the most important of these precious solid elements is iron, which is inferred to be in the core of almost all terrestrial planet.

    The amount of iron or carbon or sulfur or magnesium on or around a planet generally depends on the amount of these “metals” present in the host star, and then in molecular protoplanetary disc remains of the star’s formation. And this is where some of the outliers, the apparent oddities, come in.

    3
    A super-Earth, planet 55 Cancri e, was reported to be the first known planet to have huge layers of diamond, due in part to the high carbon-to-oxygen ratio of its host star. That conclusion has been disputed, but the planet is nonetheless unusual. Above is an artist’s concept of the diamond hypothesis. (Haven Giguere/Yale University)

    The planet 55 Cancri e, for instance, was dubbed a “diamond planet” in 2012 because the amount of carbon relative to oxygen in the star appeared to be quite high. Based on this measurement, a team hypothesized that the surface presence of abundant carbon likely created a graphite surface on the scalding super-Earth, with a layer of diamond beneath it created by the great pressures.

    “This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth,” lead researcher Nikku Madhusudhan of Yale University said in a statement at the time. “The surface of this planet is likely covered in graphite and diamond rather than water and granite.”

    As tends to happen in this early phase of exoplanet characterization, subsequent measurements cast some doubt on the diamond hypothesis. And in 2016, researchers came up with a different scenario — 55 Cancri e was likely covered in lava. But because of heavy cloud and dust cover over the planet, a subsequent group raised doubts about the lava explanation.

    But despite all this back and forth, there is a growing consensus that 55 Cancri e has an atmosphere, which is pretty remarkable given its that its “cold” side has temperatures that average of 2,400 to 2,600 degrees Fahrenheit (1,300 to 1,400 Celsius), and the hot side averages 4,200 degrees Fahrenheit (2,300 Celsius). The difference between the hot and cold sides would need to be more extreme if there were no atmosphere.

    4
    Could super-Earth HD 219134 b be a sapphire planet? (Thibaut Roger/University of Zurich)

    And then there’s another super-earth, HD 219134, that late last year was described as a planet potentially featuring vast collections of different precious stones.

    To back up for a second, researchers study the formation of planets using theoretical models and compare their results with data from observations. It is known that during their formation, stars such as the sun were surrounded by a disc of gas and dust in which planets were born. Rocky planets like the Earth were formed out of the solid bodies left over when the protoplanetary gas disc cooled and dispersed.

    Unlike the Earth however, HD 219134 most likely does not have a massive core of iron — a conclusion flowing from measurements of its density. Instead, through modeling of formation scenarios for a scalding super-Earth close to its host star, the researchers conclude the planet is likely to be rich in calcium and aluminum, along with magnesium and silicon.

    This chemical composition would allow the existence of large quantities of aluminum oxides. On Earth, crystalline aluminum oxide forms the mineral corundum. If the aluminum oxide contains traces of iron, titanium, cobalt or chromium, it will form the noble varieties of corundum, gemstones like the blue sapphire and the red ruby.

    “Perhaps it shimmers red to blue like rubies and sapphires, because these gemstones are aluminum oxides which are common on the exoplanet,” said Caroline Dorn, astrophysicist at the Institute for Computational Science of the University of Zurich.

    5
    A variation on the “eyeball planet” is a water world where the star-facing side is able to maintain a liquid-water ocean, while the rest of the surface is ice. (eburacum45/DeviantArt)

    Super-Earths, which are defined as having a size between that of Earth and Neptune, are also inferred to be the most likely to be water worlds.

    At a Goldschmidt Conference in Boston last year, a study was presented that suggests that some super-Earth exoplanets are likely extremely wet with water – much more so than Earth. Astronomers found more specifically that exoplanets which are between two and four times the size of Earth are likely to have water as a dominant component. Most are thought to be rocky and to have atmospheres, and now it seems that many have ocean, as well.

    The new findings are based on data from the Kepler Space Telescope and the Gaia mission, which show that many of the already known planets of this type (out of more than 4,000 exoplanets confirmed so far) could contain as much as 50 percent water. That upper limit is an enormous amount, compared to 0.02 percent of the water content of Earth.

    This potentially wide distribution of water worlds is perhaps not so surprising given conditions in our solar system, where Earth is wet, Venus and Mars were once wet, Neptune and Uranus are ice giants and moons such as Europa and Enceladus as global oceans beneath their crusts of ice.

    6
    Might this be the strangest planet of all? (NASA)

    As is apparent with the planetary types described so far, whether a planet is typical or atypical is very much up in the air. What is atypical this year may be found to be common in the days ahead.

    The Kepler mission concluded that small, terrestrial planets are likely more common than gas giants, but our technology doesn’t let us identify and characterize many of those smaller, Earth-sized planets.

    Many of the planets discovered so far are quite close to their host stars and thus are scalding hot. Planets orbiting red dwarf stars are an exception, but if you’re looking for habitable planets — and many astronomers are — then red dwarf planets come with other problems in terms of habitability. They are usually tidally locked and they start their days bathed in very high-energy radiation that could stertil1ze the surface for all time.

    A prime goal of the Kepler mission had been to find a planet close enough in character to Earth to be considered a twin. While they have some terrestrial candidates that could be habitable, no twin was found. This may be a function of lacking the necessary technology, or it’s certainly possible (if unlikely) that no Earth twins are out there. Or at least none with quite our collection of conditions favorable to habitability and life.

    With this in mind, my own current candidate for an especially unusual planet is, well, our own. Planet-hunting over the past almost quarter-century leads to that conclusion — for now, at least.

    And it may be that solar systems like ours are highly unusual, too. Pretty surprising, given that not long ago it was considered the norm.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds
    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 7:39 am on November 9, 2018 Permalink | Reply
    Tags: Many Worlds, , Probing The Insides of Mars to Learn How Rocky Planets Are Formed, The Tharsis region of Mars has some of the largest volcanoes in the solar system. They include Olympus Mons which is 375 miles in diameter and as much as 16 miles high. (U.S. Geological Survey)   

    From Many Worlds: “Probing The Insides of Mars to Learn How Rocky Planets Are Formed” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-11-08
    Marc Kaufman

    1
    An artist illustration of the InSight lander on Mars. InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, is designed to look for tectonic activity and meteorite impacts, study how much heat is still flowing through the planet, and track Mars’ wobble as it orbits the sun. While InSight is a Mars mission, it will help answer key questions about the formation of the other rocky planets of the solar system and exoplanets beyond. (NASA/JPL-Caltech).

    NASA/Mars InSight Lander

    In the known history of our 4.5-billion-year-old solar system, the insides of but one planet have been explored and studied. While there’s a lot left to know about the crust, the mantle and the core of the Earth, there is a large and vibrant field dedicated to that learning.

    Sometime next month, an extensive survey of the insides of a second solar system planet will begin. That planet is Mars and, assuming safe arrival, the work will start after the InSight lander touches down on November 26.

    This is not a mission that will produce dazzling images and headlines about the search for life on Mars. But in terms of the hard science it is designed to perform, InSight has the potential to tell us an enormous am0unt about the makeup of Mars, how it formed, and possibly why is it but one-third the size of its terrestrial cousins, Earth and Venus.

    “We know a lot about the surface of Mars, we know a lot about its atmosphere and even about its ionosphere,” says Bruce Banerdt, the mission’s principal investigator, in a NASA video. “But we don’t know very much about what goes on a mile below the surface, much less 2,000 miles below the surface.”

    The goal of InSight is to fill that knowledge gap, helping NASA map out the deep structure of Mars. And along the way, learn about the inferred formation and interiors of exoplanets, too.

    2
    Equitorial Mars and the InSight landing site, with noting of other sites. (NASA)

    The lander will touch down at Elysium Planitia, a flat expanse due north of the Curiosity landing site. The destination was selected because it is about as safe as a Mars landing site could be, and InSight did not need to be a more complex site with a compelling surface to explore.

    “While I’m looking forward to those first images from the surface, I am even more eager to see the first data sets revealing what is happening deep below our landing pads.” Barerdt said. “The beauty of this mission is happening below the surface. Elysium Planitia is perfect.”

    By studying the size, thickness, density and overall structure of the Martian core, mantle and crust, as well as the rate at which heat escapes from the planet’s interior, the InSight mission will provide glimpses into the evolutionary processes of all of the rocky planets in the inner solar system.

    That’s because in terms of fundamental processes that shape planetary formation, Mars is an ideal subject.

    It is big enough to have undergone the earliest internal heating and differentiation (separation of the crust, mantle and core) processes that shaped the terrestrial planets (Earth, Venus, Mercury, our moon), but small enough to have retained the signature of those processes over the next four billion years.

    So Mars may contain the most in-depth and accurate record in the solar system of these processes. And because Mars has been less geologically active than the Earth — it does not have plate tectonics, for example — it has retains a more complete evolutionary record in its own basic planetary building blocks. In terms of deep planet geophysics, it is often described as something of a fossil.

    By using geophysical instruments like those used on Earth, InSight will measure the fingerprints of the processes of terrestrial planet formation, as well as measuring the planet’s “vital signs.” They include the “pulse” (seismology), “temperature” (heat flow probe), and “reflexes” (precision tracking).

    One promising way InSight will peer into the Martian interior is by studying motion underground — what we know as marsquakes.

    NASA has not attempted to do this kind of science since the Viking mission. Both Viking landers had their seismometers on top of the spacecraft, where they produced noisy data. InSight’s seismometer will be placed directly on the Martian surface, which will provide much cleaner data.

    As described by the agency, “NASA have seen a lot of evidence suggesting Mars has quakes. But unlike quakes on Earth, which are mostly caused by tectonic plates moving around, marsquakes would be caused by other types of tectonic activity, such as volcanism and cracks forming in the planet’s crust.

    “In addition, meteor impacts can create seismic waves, which InSight will try to detect.

    “Each marsquake would be like a flashbulb that illuminates the structure of the planet’s interior. By studying how seismic waves pass through the different layers of the planet (the crust, mantle and core), scientists can deduce the depths of these layers and what they’re made of. In this way, seismology is like taking an X-ray of the interior of Mars.”

    3
    The InSight seismometer, developed by European partners and JPL, consists of a total of six seismic sensors that record the vibrations of the Martian soil in three directions in space and at two different frequency ranges. ges allows them to be mathematically combined into a single extremely broadband seismometer. In order to protect the seismometer against wind and strong temperature fluctuations, a protective dome (Wind and Thermal Shield, WTS) will be placed over it. (German Aerospace Center [DLR])

    Scientists think it’s likely they’ll see between a dozen and a hundred marsquakes over the course of two Earth years. The quakes are likely to be no bigger than a 6.0 on the Richter scale, which would be plenty of energy for revealing secrets about the planet’s interior.

    Another area of scientific interest involves whether or not the core of Mars is liquid. InSight’s Rotation and Interior Structure Experiment, RISE, will help answer that question by tracking the location of the lander to determine just how much Mars’ North Pole wobbles as it orbits the sun.

    These observations will provide information on the size of Mars’ iron-rich core and will help determine whether the core is liquid. It will also help determine which other elements, besides iron, may be present.

    The InSight science effort includes a self-hammering heat probe that will burrow down to 16 feet into the Martian soil and will for the first time measure the heat flow from the planet’s interior. Combining the rate of heat flow with other InSight data will reveal how energy within the planet drives changes on the surface.

    This is especially important in trying to understand the presence and size of some of the solar system’s largest shield volcanoes in the solar system, a region known as Tharsis Mons.

    3
    The Tharsis region of Mars has some of the largest volcanoes in the solar system. They include Olympus Mons, which is 375 miles in diameter and as much as 16 miles high. (U.S. Geological Survey)

    Heat escaping from deep within the planet drives the formation of these types of features, as well as many others on rocky planets.

    InSight is not an astrobiology mission — no searching for life beyond Earth.

    But it definitely is part of the process by which scientists will learn what planet formation and the dynamics of their interiors says about whether a planet can be home to life.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds
    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 12:57 pm on November 1, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds, , ,   

    From Many Worlds: “The Kepler Space Telescope Mission Is Ending But Its Legacy Will Keep Growing” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-11-01
    Marc Kaufman

    NASA/Kepler Telescope

    As of October 2018, the planet-hunting spacecraft has been in space for nearly a decade. (NASA via AP)

    The Kepler Space Telescope is dead. Long live the Kepler.

    NASA officials announced on Tuesday that the pioneering exoplanet survey telescope — which had led to the identification of almost 2,700 exoplanets — had finally reached its end, having essentially run out of fuel. This is after nine years of observing, after a malfunctioning steering system required a complex fix and change of plants, and after the hydrazine fuel levels reached empty.

    While the sheer number of exoplanets discovered is impressive the telescope did substantially more: it proved once and for all that the galaxy is filled with planets orbiting distant stars. Before Kepler this was speculated, but now it is firmly established thanks to the Kepler run.

    It also provided data for thousands of papers exploring the logic and characteristics of exoplanets. And that’s why the Kepler will indeed live long in the world of space science.

    “As NASA’s first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the solar system and beyond,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington.

    “Not only did it show us how many planets could be out there, it sparked an entirely new and robust field of research that has taken the science community by storm. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars.”

    1
    The Kepler Space Telescope was focused on hunting for planets in this patch of the Milky Way. After two of its four spinning reaction wheels failed, it could no longer remain steady enough to stare that those distant stars but was reconfigured to look elsewhere and at a different angle for the K2 mission. (Carter Roberts/NASA)

    Kepler was initially the unlikely brainchild of William Borucki, its founding principal investigator who is now retired from NASA’s Ames Research Center in California’s Silicon Valley.

    3
    William Borucki, originally the main champion for the Kepler idea and later the principal investigator of the mission. His work at NASA went back to the Apollo days. (NASA)

    When he began thinking of designing and proposing a space telescope that could potentially tell us how common distant exoplanets were — and especially smaller terrestrial exoplanets like Earth – the science of extra solar planets was at a very different stage.

    “When we started conceiving this mission 35 years ago we didn’t know of a single planet outside our solar system,” Borucki said. “Now that we know planets are everywhere, Kepler has set us on a new course that’s full of promise for future generations to explore our galaxy.”

    The space telescope was launched in 2009. While Kepler did not find the first exoplanets — that required the work of astronomers using a different technique of observing based on the “wobble” of stars caused by orbiting planets — it did change the exoplanet paradigm substantially.

    Not only did it prove that exoplanets are common, it found that planets outnumber stars in our galaxy (which has hundreds of billions of those stars.)

    In addition it found that small, terrestrial-size planets are common as well, with some 20 to 50 percent of stars likely to have planets of that size and type. And what menagerie of planets it found out there.

    Among the greatest surprises: The Kepler mission provided data showing that the most common sized planets in the galaxy fall somewhere between Earth and Neptune, a type of planet that isn’t present in our solar system.

    It found solar systems of all sizes as well, including some with many planets (as many as eight) orbiting close to their host star.

    The discovery of these compact systems, generally orbiting a red dwarf star, raised questions about how solar systems form: Are these planets “born” close to their parent star, or do they form farther out and migrate in?

    So far, more than 2,500 peer-reviewed papers have been published using Kepler data, with substantial amounts of that data still unmined.

    Natalie Batalha was the project and mission scientist for Kepler for much of its run, and I asked her about its legacy.

    2
    Astrophysicist Natalie Batalha was the Kepler project and mission scientist for a decade. She left NASA recently for the University of California at Santa Cruz “to carry on the Kepler legacy” by creating an interdisciplinary center for the study of planetary habitability.

    “When I think of Kepler’s influence across all of astrophysics, I’m amazed at what such a simple experiment accomplished,” she wrote in an email. “You’d be hard-pressed to come up with a more boring mandate — to unblinkingly measure the brightnesses of the same stars for years on end. No beautiful images. No fancy spectra. No landscapes. Just dots in a scatter plot.

    “And yet time-domain astronomy exploded. We’d never looked at the Universe quite this way before. We saw lava worlds and water worlds and disintegrating planets and heart-beat stars and supernova shock waves and the spinning cores of stars and planets the age of the galaxy itself… all from those dots.”

    4
    The Kepler-62 system is but one of many solar systems detected by the space telescope. The planets within the green discs are in the habitable zones of the stars — where water could be liquid at times. (NASA)

    While Kepler provided remarkable answers to questions about the overall planetary makeup of our galaxy, it did not identify smaller planets that will be directly imaged, the evolving gold standard for characterizing exoplanets. The 150,000 stars that the telescope was observing were very distant, in the range of a few hundred to a few thousand light-years away. One light year is about 6 trillion (6,000,000,000,000) miles.

    Nonetheless, Kepler was able to detect the presence of a handful of Earth-sized planets in the habitable zones of their stars. The Kepler-62 system held one of them, and it is 1200 light-years away. In contrast, the four Earth-sized planets in the habitable zone of the much-studied Trappist-1 system are 39 light-years away.

    Kepler made its observations using the the transit technique, which looks for tiny dips in the amount of light coming from a star caused by the presence of a planet passing in front of the star. While the inference that exoplanets are ubiquitous came from Kepler results, the telescope was actually observing but a small bit of the sky. It has been estimated that it would require around 400 space telescopes like Kepler to cover the whole sky.

    What’s more, only planets whose orbits are seen edge-on from Earth can be detected via the transit method, and that rules out a vast number of exoplanets.

    The bulk of the stars that were selected for close Kepler observation were more or less sun-like, but a sampling of other stars occurred as well. One of the most important factors was brightness. Detecting minuscule changes in brightness caused by transiting planet is impossible if the star is too dim.

    Four years into the mission, after the primary mission objectives had been met, mechanical failures temporarily halted observations. The mission team was able to devise a fix, switching the spacecraft’s field of view roughly every three months. This enabled an extended mission for the spacecraft, dubbed K2, which lasted as long as the first mission and bumped Kepler’s count of surveyed stars up to more than 500,000.

    But it was inevitable that the mission would come to an end sooner rather than later because of that dwindling fuel supply, needed to keep the telescope properly pointed.

    Kepler cannot be refueled because NASA decided to place the telescope in an orbit around the sun that is well beyond the influence of the Earth and moon — to simplify operations and ensure an extremely quiet, stable environment for scientific observations. So Kepler was beyond the reach of any refueling vessel. The Kepler team compensated by flying considerably more fuel than was necessary to meet the mission objectives.

    The video below explains what will happen to the Kepler capsule once it is decommissioned. But a NASA release explains that the final commands “will be to turn off the spacecraft transmitters and disable the onboard fault protection that would turn them back on. While the spacecraft is a long way from Earth and requires enormous antennas to communicate with it, it is good practice to turn off transmitters when they are no longer being used, and not pollute the airwaves with potential interference.”

    And so Kepler will actually continue orbiting for many decades, just as its legacy will continue long after operations cease.

    Kepler’s follow-on exoplanet surveyor — the Transiting Exoplanet Survey Satellite or TESS — was launched this year and has begun sending back data.

    NASA/MIT TESS

    Its primary mission objective is to survey the brightest stars near the Earth for transiting exoplanets. The TESS satellite uses an array of wide-field cameras to survey some 85% of the sky, and is planned to last for two years.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 12:21 pm on October 24, 2018 Permalink | Reply
    Tags: , , , , Many Worlds, What Would Happen If Mars And Venus Swapped Places?   

    From Many Worlds: “What Would Happen If Mars And Venus Swapped Places?” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-10-24
    Elizabeth Tasker

    1
    Venus, Earth and Mars (ESA).

    What would happen if you switched the orbits of Mars and Venus? Would our solar system have more habitable worlds?

    It was a question raised at the “Comparative Climatology of Terrestrial Planets III”; a meeting held in Houston at the end of August. It brought together scientists from disciplines that included astronomers, climate science, geophysics and biology to build a picture of what affects the environment on rocky worlds in our solar system and far beyond.

    The question regarding Venus and Mars was proposed as a gedankenexperiment or “thought experiment”; a favorite of Albert Einstein to conceptually understand a topic. Dropping such a problem before the interdisciplinary group in Houston was meat before lions: the elements of this question were about to be ripped apart.

    The Earth’s orbit is sandwiched between that of Venus and Mars, with Venus orbiting closer to the sun and Mars orbiting further out. While both our neighbors are rocky worlds, neither are top picks for holiday destinations.

    Mars has a mass of just one-tenth that of Earth, with a thin atmosphere that is being stripped by the solar wind; a stream of high energy particles that flows from the sun. Without a significant blanket of gases to trap heat, temperatures on the Martian surface average at -80°F (-60°C). Notably, Mars orbits within the boundaries of the classical habitable zone (where an Earth-like planet could maintain surface water) but the tiny planet is not able to regulate its temperature as well as the Earth might in the same location.

    2
    The classical habitable zone around our sun marks where an Earth-like planet could support liquid water on the surface (Cornell University).

    Unlike Mars, Venus has nearly the same mass as the Earth. However, the planet is suffocated by a thick atmosphere consisting principally of carbon dioxide. The heat-trapping abilities of these gases soar surface temperatures to above a lead-melting 860°F (460°C).

    But what if we could switch the orbits of these planets to put Mars on a warmer path and Venus on a cooler one? Would we find that we were no longer the only habitable world in the solar system?

    “Modern Mars at Venus’s orbit would be fairly toasty by Earth standards,” suggests Chris Colose, a climate scientist based at the NASA Goddard Institute for Space Studies and who proposed the topic for discussion.

    Dragging the current Mars into Venus’s orbit would increase the amount of sunlight hitting the red planet. As the thin atmosphere does little to affect the surface temperature, average conditions should rise to about 90°F (32°C), similar to the Earth’s tropics. However, Mars’s thin atmosphere continues to present a problem.

    Colose noted that without a thicker atmosphere or ocean, heat would not be transported efficiently around Mars. This would lead to extreme seasons and temperature gradients between the day and night. Mars’s thin atmosphere produces a surface pressure of just 6 millibars, compared to 1 bar on Earth. At such low pressures, the boiling point of water plummets to leave all pure surface water frozen or vaporized.

    Mars does have have ice caps consisting of frozen carbon dioxide, with more of the greenhouse gas sunk into the soils. A brief glimmer of hope for the small world arose in the discussion with the suggestion these would be released at the higher temperatures in Venus’s orbit, providing Mars with a thicker atmosphere.

    3
    The surface of Mars captured by a selfie taken by the Curiosity rover at a site named Mojave. (NASA/JPL-Caltech/MSSS.)

    However, recent research suggests there is not enough trapped carbon dioxide to provide a substantial atmosphere on Mars. In an article published in Nature Astronomy, Bruce Jakosky from the University of Colorado and Christopher Edwards at Northern Arizona University estimate that melting the ice caps would offer a maximum of a 15 millibars atmosphere.

    The carbon dioxide trapped in the Martian rocks would require temperatures exceeding 300°C to be liberated, a value too high for Mars even at Venus’s orbit. 15 millibars doubles the pressure of the current atmosphere on Mars and surpasses the so-called “triple point” of water that should permit liquid water to exist. However, Jakosky and Edwards note that evaporation would be rapid in the dry martian air. Then we hit another problem: Mars is not good at holding onto atmosphere.

    Orbiting Mars is NASA’s Mars Atmosphere and Volatile Evolution Mission (MAVEN).

    NASA Mars MAVEN

    Data from MAVEN has revealed that Mars’s atmosphere has been stripped away by the solar wind. It is a problem that would be exacerbated at Venus’s orbit.

    “Atmospheric loss would be faster at Venus’s current position as the solar wind dynamic pressure would increase,” said Chuanfei Dong from Princeton University, who had modeled atmospheric loss on Mars and extrasolar planets.

    4
    Artist’s rendering of a solar storm hitting Mars and stripping ions from the planet’s upper atmosphere (credit: NASA/GSFC).

    This “dynamic pressure” is the combination of the density of particles from the solar wind and their velocity. The velocity does not change greatly between Mars and Venus —explained Dong— but Venus’s closer proximity to the sun boosts the density by almost a factor of 4.5. This would mean that atmosphere on Mars would be lost even more rapidly than at its current position.

    “I suspect it would just be a warmer rock,” Colose concluded.

    While Mars seems to fare no better at Venus’s location, what if Venus were to be towed outwards to Mars’s current orbit? Situated in the habitable zone, would this Earth-sized planet cool-off to become a second habitable world?

    Surprisingly, cooling Venus might not be as simple as reducing the sunlight. Venus has a very high albedo, meaning that the planet reflects roughly 75% of the radiation it receives. The stifling temperatures at the planet surface are due not to a high level of sunlight but to the thickness of the atmosphere. Conditions on the planet may therefore not be immediately affected if Venus orbited in Mars’s cooler location.

    “Venus’s atmosphere is in equilibrium,” pointed out Kevin McGouldrick from the University of Colorado and contributing scientist to Japan’s Akatsuki mission to explore Venus’s atmosphere. “Meaning that its current structure does depend on the radiation from the sun. If you change that radiation then the atmosphere will eventually adjust but it’s not likely to be quick.”

    Exactly what would happen to Venus’s 90 bar atmosphere in the long term is not obvious. It may be that the planet would slowly cool to more temperate conditions. Alternatively, the planet’s shiny albedo may decrease as the upper atmosphere cools. This would allow Venus to absorb a larger fraction of the radiation that reached its new orbit and help maintain the stifling surface conditions. To really cool the planet down, Venus may have to be dragged out beyond the habitable zone.

    “Past about 1.3 au, carbon dioxide will begin to condense into clouds and also onto the surface as ice,” said Ramses Ramirez from the Earth-Life Sciences Institute (ELSI) in Tokyo, who specializes in modelling the edges of the habitable zone. (An “au” is an astronomical unit, which is the distance from our sun to Earth.)

    Once carbon dioxide condenses, it can no longer act as a greenhouse gas and trap heat. Instead, the ice and clouds typically reflect heat away from the surface. This defines the outer edge of the classical habitable zone when the carbon dioxide should have mainly condensed out of the atmosphere at about 1.7 au. The result should be a rapid cooling for Venus. However, this outer limit for the habitable zone was calculated for an Earth-like atmosphere.

    “Venus has other things going on in its atmosphere compared to Earth, such as sulphuric acid clouds,” noted Ramirez. “and it is much drier, so this point (where carbon dioxide condenses) may be different for Venus.”

    If Venus was continually dragged outwards, even the planet’s considerable heat supply would become exhausted.

    “If you flung Venus out of the solar system as a rogue planet, it would eventually cool-off!” pointed out Max Parks, a research assistant at NASA Goddard.

    It seems that simply switching the orbits of the current Venus and Mars would not produce a second habitable world. But what if the two planets formed in opposite locations? Mars is unlikely to have fared any better, but would Venus have avoided forming its lead-melting atmosphere and become a second Earth?

    At first glance, this seems very probable. If the Earth was pushed inwards to Venus’s orbit, then water would start to rapidly evaporate. Like carbon dioxide, water vapour is a greenhouse gas and helps trap heat. The planet’s temperature would therefore keep increasing in a runaway cycle until all water had evaporated. This “runaway greenhouse effect” is a possible history for Venus, explaining its horrifying surface conditions. If the planet had instead formed within the habitable zone, this runaway process should be avoided as it had been for the Earth.

    “When I suggested this topic, I wondered whether two inhabited planets would exist (the Earth and Venus) if Mars and Venus formed in opposite locations,” Colose said. “Being at Mars’s orbit would avoid the runaway greenhouse and a Venus-sized planet wouldn’t have its atmosphere stripped as easily as Mars.”

    But discussion within the group revealed that it is very hard to offer any guarantees that a planet will end up habitable. One example of the resultant roulette game is the planet crust. The crust of Venus is a continuous lid and not series of fragmented plates as on Earth. Our plates allow a process known as plate tectonics, whereby nutrients are cycled through the Earth’s surface and mantle to help support life. Yet, it is not clear why the Earth formed this way but Venus did not.

    One theory is that the warmer Venusian crust healed breaks rapidly, preventing the formation of separate plates. However, research done by Matt Weller at the University of Texas suggests that the formation of plate tectonics might be predominantly down to luck. Small, random fluctuations might send two otherwise identical planets down different evolutionary paths, with one developing plate tectonics and the other a stagnant lid. If true, even forming the Earth in exactly the same position could result in a tectonic-less planet.

    5
    A rotating globe with tectonic plate boundaries indicated as cyan lines (credit: NASA/Goddard Space Flight Center Scientific Visualization Studio).

    Venus’s warmer orbit may have shortened the time period in which plate tectonics could develop, but moving the planet to Mars’s orbit offers no guarantees of a nutrient-moving crust.

    Yet whether plate tectonics is definitely needed for habitability is also not known. It was pointed out during the discussion that both Mars and Venus show signs of past volcanic activity, which might be enough action to produce a habitable surface under the right conditions.

    Of course, moving a planet’s orbit is beyond our technological abilities. There are other techniques that could be tried, such as an idea by Jim Green, the NASA chief scientist and Dong involving artificially shielding Mars’s atmosphere from the solar wind.

    “We reached the opposite conclusion to Bruce’s paper,” Dong noted cheerfully. “That is might be possible to use technology to give Mars an atmosphere. But it is fun to hear different voices and this is the reason why science is so interesting!”

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:44 am on September 28, 2018 Permalink | Reply
    Tags: Astrobiology Grand Tour, , , , Community of microbial mats living on top. They are some of the Earth’s earliest ecosystems., , First oxygen-producing bacteria-cyanobacteria, , Karijini National Park, Living stromatolites of Shark Bay, Many Worlds, , , , Pilbara in Western Australia, Pilbara is also where the oldest mineral on Earth –a zircon dated at 4.4 billion years old — was discovered four years ago in the Jack Hills region, State of Western Australia, Stromatolites literally mean “layered rocks”, The most important contribution of stromatolites – terraforming the Earth, These ancient life forms left behind geological footprints reminding us they were here first, Time-Traveling in the Australian Outback in Search of Early Earth   

    From Many Worlds: “Time-Traveling in the Australian Outback in Search of Early Earth” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-09-28
    Nicholas Siegler, Chief Technologist for NASA’s Exoplanet Exploration Program at the Jet Propulsion Laboratory with the help of doctoral student Markus Gogouvitis, at the University of New South Wales, Australia and Georg-August-University in Gottingen, Germany.

    1
    These living stromatolites at Shark Bay, Australia are descendants of similar microbial/sedimentary forms once common around the world. They are among the oldest known repositories of life. Most stromatolites died off long ago, but remain at Shark Bay because of the high salinity of the water. (Tourism, Western Australia)

    This past July I joined a group of geologists, geochemists, microbiologists, and fellow astronomers on a tour of some of the best-preserved evidence for early life.

    Entitled the Astrobiology Grand Tour, it was a trip led by Dr. Martin Van Kranendonk, a structural geologist from the University of New South Wales, who had spent more than 25 years surveying Australia’s Pilbara region. Along with his graduate students he had organized a ten-day excursion deep into the outback of Western Australia to visit some of astrobiology’s most renowned sites.

    The trip would entail long, hot days of hiking through unmaintained trails on loose surface rocks covered by barb-like bushes called spinifex. As I was to find out, nature was not going to give up its secrets easily. And there were no special privileges allocated to astrophysicists from New Jersey [? no mention of anyone from New Jersey].

    2
    The route of our journey back in time. (Google Earth/Markus Gogouvitis /Martin Van Kranendonk)

    The state of Western Australia, almost four times the size of the American state of Texas but with less than a tenth of the population (2.6 million), is the site of many of astrobiology’s most heralded sites. For more than three billion years, it has been one of the most stable geologic regions in the world.

    It has been ideal for geological preservation due to its arid conditions, lack of tectonic movement, and remoteness. The rock records have in many places survived and are now able to tell their stories (to those who know how to listen).

    3
    The classic red rocks of the Pilbara in Western Australia, with the needle sharp spinifex bushes in the foreground. (Nick Siegler, NASA/JPL-Caltech)

    Our trip began with what felt like a pilgrimage. We left Western Australia’s largest city Perth and headed north for Shark bay. It felt a bit like a pilgrimage because the next morning we visited one of modern astrobiology’s highlights – the living stromatolites of Shark Bay.

    Stromatolites literally mean “layered rocks”. It’s not the rocks that are alive but rather the community of microbial mats living on top. They are some of the Earth’s earliest ecosystems.

    We gazed over these living microbial communities aloft on their rock perches and marveled at their exceptional longevity — the species has persisted for over three billion years. Their ancestors had survived global mass extinctions, planet-covering ice glaciers, volcanic activity, and all sorts of predators. Once these life forms took hold they were not going to let go.

    4
    The stromatolites forming today in the shallow waters of Shark Bay, Australia are built by colonies of microbes that capture ocean sediments. (University of Wisconsin-Madison)

    The photosynthetic bacteria that built ancient stromatolites played a central role of our trip for three reasons:

    Their geological footprints allowed scientists to date the evolution of early life and at times gain insight into the environments in which they grew.
    They eventually harbored the first oxygen-producing bacteria and played a central role in creating our oxygen-rich atmosphere.
    By locating ever-increasingly older microbial fossils we observed a lower limit to the age of the first life forms.. Given photosynthesis is not a simple process, the first life forms must have been simpler. Speculating, perhaps a few hundred million years earlier so that the first life form on Earth may have originated at four billion years ago.

    When viewed under a microscope, you can see the mats are made of millions of single cell bacteria and archaea, among the simplest life forms we know. Within these relatively thin regions are multiple layers of specialized microbial communities that live interdependently.

    Bacteria in the top layer evolved to harvest sunlight to live and grow via photosynthesis. Their waste products include oxygen as well as important nutrients for many different bacterial species within underlying layers. And this underlying layer’s waste product would do the same for the layer beneath it, perfectly recycling each other’s waste. The oldest forms of life that we know of had learned to co-exist together in a chemically interdependent environment.

    5
    Broken piece of a living stromatolite, which was was remarkably spongy and smelled slightly salty, indicative of the hypersaline bay that has contributed to their survival by making bacteria and other organisms undesirable. What was actually most remarkable of the visit to Hamelin pool was how quiet it was. There were no seagulls and other birds because of the hypersaline environment. They had gone elsewhere for their meals. (Nick Siegler, NASA/JPL-Caltech)

    We saw ripped up portions of the mats that washed upon the shore at Hamelin pool in Shark Bay. A whole ecosystem held in one’s hand. Thousands of millions of years ago ancient relatives of these microbes thrived in shallow waters all around our planet, and left behind fossilized remains. But due to the evolution of grazing organisms these microbial structures are nowadays constrained to very specific environments. In the case of Shark Bay, the very high salt contents of this inlet have warded off most predators providing the microbes with a safe haven to live.

    Ironically, the rocks, which help identify these ancient life forms, at the time were just a nuisance for the living microbes.

    Small fine grains of sedimentary rock carried along in the daily tides would occasionally get stuck in the sticky mucus the microbes would secrete. In addition, the photosynthetic bacteria found at Shark Bay may have been inadvertently making their own rock by depleting the carbon dioxide in the surrounding water as part of photosynthesis and precipitating carbonate, adding to the grains of sediment trapped within the sticky top layer.

    Over time, the grains from both the sedimentary and precipitated rocks would cover the surface and block the sunlight for which these organisms had evolved to depend on. As an evolutionary tour de force, the photosynthetic microbes learned to migrate upward, leaving the newly formed rock layers behind.

    These secondary rock fossils today showcase visually observable crinkly, frequently conical shapes, in stark contrast to abiotic sedimentary rocks. These ancient life forms left behind geological footprints reminding us they were here first.

    Now to the most important contribution of stromatolites – terraforming the Earth.

    Living in shallow water, the top most layer of the Shark Bay microbial mats are known to host cyanobacteria, photosynthetic bacteria that produce oxygen as a byproduct. Scientists don’t know what the first bacteria produced as they harnessed the energy of the Sun. But they do know that they eventually started producing oxygen.

    In the evolution of life that eventually led to all plants and animals, this was one of the great events. More than 2.5 billion years ago, ancient bacteria began diligently producing oxygen in the oceans. Earth’s atmosphere began to irreversibly shift from its original, oxygen-free existence, to an oxic one, initiating the formation of our ozone layer and paving the way for the evolution of more complex life. Our planet has been terraformed by micro-organisms!

    It was in the Karijini National Park where we went back in time (2.4 billion years) and observed an extraordinary piece of evidence for the early production of oxygen in Earth’s oceans, a time before oxygen made a strong presence in our atmosphere.

    6
    Banded iron formation at Karajini National Park. (Nick Siegler, NASA-JPL/Caltech)

    We saw a massive gorge with steep vertical walls carved out by flowing water. As oxygen production by early bacteria increased below the water surface it would react with dissolved iron ions (early oceans were iron-rich) causing iron oxides to precipitate and settle to the bottom.

    For reasons not entirely understood — perhaps related to seasonal or temperature effects– the amount of new oxygen temporarily decreased and iron ion remained soluble in the oceans and other types of sediments accumulated, carbonates, slate, and shale. And then, just as before, the oxygen reappeared creating a new layer of precipitated iron.

    The result was a banded sedimentary rock, a litmus test to a changing world, where oxygen would be the reactive ingredient leading to larger and more complex life forms. As the oxygen production no longer cycled, the oxygen went on to saturate the ocean and then accumulated in the Earth’s atmosphere eventually to the levels we have today.

    7
    Banded iron formation at Karajini. (Nick Siegler, NASA-JPL/Caltech)

    After a day of looking down at rocks and spinifex it was both a relief and a joy to look up at the glorious Western Australian night sky. Far away from the light pollution of modern cities, each night would greet us with an awe-inspiring starlit sky. It never got old to remember we are part of a vast network of stars suspended in an infinite space.

    The nights would start with the appearance of Venus well before sundown followed shortly by the innermost planet Mercury and then Jupiter and Saturn. It didn’t take long after sunset to see the renowned Southern Cross. Mars joined the evening as well, perfectly appearing on the arc called the ecliptic.

    But nothing stirred the group more than the emergence of the swath of stars of the Milky Way, the disk of our home galaxy where its spiral arms all lie. The nights would be so clear that one could actually see the dark clouds of gas and dust that block large portions of the galaxy’s stars from shining through. We partook in the well-known tradition connecting individual points of light to form exotic creatures like scorpions and centaurs. But we also we followed the inverted approach of the Aborigines and connected the dark patches. Only then did we see the emu of the Milky Way. I would never have thought of connecting the darkness.

    The night sky appeared even more special knowing that each of its stellar members likely host planetary systems like our own. How many of them host life? Maybe even civilizations? The numbers are in their favor.

    At the half-way point of our trip we hiked to an ancient granite region in the red rocks of the Pilbara which contain the world’s largest concentration of Pleistocene rock art also known as petroglyphs. These etchings are believed to be 6,000 to 20, 000 years old.

    The artists used no pigments, but rather rocks to pound/chisel shapes into the desert varnish, a thin dark film (possibly of microbial origin) that typically covers exposed rock surfaces in hyper arid regions. We came across many stylized male and female figures with highlighted genitalia as well as animals such as emus and kangaroos. Little is known about the people who created these art works. They left no clues to their origin or fate.

    8
    Rock art by aboriginal people done 6,000 to 20,000 years ago. The shapes were etched into an existing varnish on the rock. (Nick Siegler, NASA-JPL/Caltech)

    Pilbara is also where the oldest mineral on Earth –a zircon dated at 4.4 billion years old — was discovered four years ago in the Jack Hills region. Because of the geological history of the region, it is a frequent (if hardscrabble) site where many geologists and geochemists specializing in ancient Earth do their work.

    In the last several days of the tour we encountered ever-increasing older evidence of stromatolites extending out to circa 3.5 billion years, about 75% of the history of the Earth. I expected the quality of the stromatolites to degrade as we went back in time and it looked like I was right until I saw a remarkably large rock in a locality called the Strelley Pool Formation. The rock measuring approximately 1.5 meters in all three directions gave a rare view of ancient stromatolites from all sides and an unequivocal interpretation of past life.

    The shapes of the embedded rocks formed by the microbial mats from the top view clearly show the elliptical areas where the bacteria inched upwards to acquire sunlight. Regions between the conical stromatolites were filled in by carbonate sediments in ancient shallow waters. These were later chemically altered to silica-rich rocks through alteration and etching of minerals by fluids. Silicified rocks are very weather-resistant, making them a great medium to preserve fossils for billions of years.

    The side views of the stromatolite-laden rock revealed the expected conical layered shapes we saw in younger rocks (and in the living stromatolites of Shark Bay). Everything we had learned about stromatolite structures was clearly visible in this circa 3.43 billion year old example. It is astounding to realize that complex phototrophic (light-eating) organisms, even if not yet oxygen producing, were around during the deposition of the Strelley Pool Formation.

    9
    Detail of Strelley Pool stromatolite fossil. (Nick Siegler, NASA-JPL/Caltech)

    It is not unreasonable to speculate that the earliest life forms are even older by perhaps a few more hundred million years or so. There is evidence for even more ancient stromatolites in Greenland (3.7 billion years old) and isotope carbon evidence, with considerable controversy, in Nuvvuagittuq greenstone belt in northern Quebec, Canada (4.28 billion years old). Hence, life on Earth may have emerged within 500 million years from its formation. That is astonishingly rapid.

    Was Earth an exception or the rule? What does that say for possible life on exoplanets?

    Our tour came to an end on July 11. We had traveled over 1,600 miles through Australia’s outback, from Western Australia’s biggest city Perth, all the way up to Port Hedland at the north coast. We were privileged to see the country in ways that very few people get a chance to, and to be steeped in the multidisciplinary sciences of astrobiology while seeing some of its iconic ground.

    I had seen some of the earliest evidence for life and the pivotal effect it had on our environment. For those 10 days I learned what it was like to be a time traveler.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:25 am on September 5, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds,   

    From Many Worlds: “A National Strategy for Finding and Understanding Exoplanets (and Possibly Extraterrestrial Life)” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-09-05
    Marc Kaufman

    1
    The National Academies of Science, Engineering and Medicine took an in-depth look at what NASA, the astronomy community and the nation need to grow the burgeoning science of exoplanets — planets outside our solar system that orbit a star. (NAS)

    An extensive, congressionally-directed study of what NASA needs to effectively learn how exoplanets form and whether some may support life was released today, and it calls for major investments in next-generation space and ground telescopes. It also calls for the adoption of an increasingly multidisciplinary approach for addressing the innumerable questions that remain unanswered.

    While the recommendations were many, the top line calls were for a sophisticated new space-based telescope for the 2030s that could directly image exoplanets, for approval and funding of the long-delayed and debated WFIRST space telescope, and for the National Science Foundation and to help fund two of the very large ground-based telescopes now under development.

    The study of exoplanets has seen remarkable discoveries in the past two decades. But the in-depth study from the private, non-profit National Academies of Sciences, Engineering and Medicine concludes that there is much more that we don’t understand than that we do, that our understandings are “substantially incomplete.”

    So the two overarching goals for future exoplanet science are described as these:

    To understand the formation and evolution of planetary systems as products of star formation and characterize the diversity of their architectures, composition, and environments.
    To learn enough about exoplanets to identify potentially habitable environments and search for scientific evidence of life on worlds orbiting other stars.

    Given the challenge, significance and complexity of these science goals, it’s no wonder that young researchers are flocking to the many fields included in exoplanet science. And reflecting that, it is perhaps no surprise that the NAS survey of key scientific questions, goals, techniques, instruments and opportunities runs over 200 pages. (A webcast of a 1:00 pm NAS talk on the report can be accessed here.)

    2
    Artist’s concept showing a young sun-like star surrounded by a planet-forming disk of gas and dust. (NASA/JPL-Caltech/T. Pyle)

    These ambitious goals and recommendations will now be forwarded to the arm of the National Academies putting together 2020 Astronomy and Astrophysics Decadal Survey — a community-informed blueprint of priorities that NASA usually follows.

    This priority-setting is probably most crucial for the two exoplanet direct imaging missions now being studied as possible Great Observatories for the 2030s — the paradigm-changing space telescopes NASA has launched almost every decade since the 1970s.

    HabEx (the Habitable Exoplanet Observatory) and LUVOIR (the Large UV/Optical/IR Surveyor) are two direct-imaging exoplanet projects in conception phase that would indeed significantly change the exoplanet field.

    NASA Habitable Exoplanet Imaging Mission (HabEx) The Planet Hunter

    NASA Large UV Optical Infrared Surveyor (LUVOIR)

    Both would greatly enhance scientists’ ability to detect and characterize exoplanets. But the more ambitious LUVOIR in particular, would not only find many exoplanets in all stages of formation, but could readily read chemical components of the atmospheres and thereby get clear data on whether the planet was habitable or even if it supported life. The LUVOIR would provide either an 8 meter or a record-breaking 15-meter space telescope, while HabEx would send up a 4 meter mirror.

    HabEx and LUVOIR are competing with two other astrophysics projects for that Great Observatory designation, and so NAS support now and prioritizing later is essential if they are to become a reality.

    3
    An artist notional rendering of an approximately 15-meter telescope in space. This image was created for an earlier large space telescope feasibility project called ATLAST, but it is similar to what is being discussed inside and outside of NASA as a possible great observatory after the James Webb Space Telescope and the Wide-Field Infrared Survey Telescope. (NASA)

    These two potential Great Observatories will be costly and would take many years to design and build. As the study acknowledges and explains, “While the committee recognized that developing a direct imaging capability will require large financial investments and a long time scale to see results, the effort will foster the development of the scientific community and technological capacity to understand myriad worlds.”

    So a lot is at stake. But with budget and space priorities in flux, the fate of even the projects given the highest priority in the Decadal Survey remains unclear.

    That’s apparent in the fact that one of the top recommendations of today’s study is the funding of the number one priority put forward in the 2010 Astronomy and Astrophysics Decadal Survey — the Wide Field Infrared Survey Telescope (WFIRST.)

    NASA/WFIRST

    The project — which would boost the search for exoplanets further from their stars than earlier survey missions– was cancelled in the administration’s proposed 2019 federal budget. Congress has continued funding some development of this once top priority, but its future nonetheless remains in doubt.

    WFIRST could have the capability of directly imaging exoplanets if it were built with technology to block out the blinding light of the star around which exoplanets would be orbiting — doing so either with internal coronagraph or a companion starshade. This would be novel technology for a space-based telescope, and the NAS survey recommends it as well.

    4
    An artist’s rendering of a possible “starshade” that could be launched to work with WFIRST or another space telescope and allow the telescope to take direct pictures of other Earth-like planets. (NASA/JPL-Caltech)

    The list of projects the study recommends is long, with these important additions:

    “Ground-based astronomy – enabled by two U.S.-led telescopes – will also play a pivotal role in studying planet formation and potentially terrestrial worlds, the report says. The future Giant Magellan telescope (GMT) and proposed Thirty Meter Telescope (TMT) would allow profound advances in imaging and spectroscopy – absorption and emission of light – of entire planetary systems.

    Giant Magellan Telescope, to be at the Carnegie Institution for Science’s Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high

    TMT-Thirty Meter Telescope, proposed and now approved for Mauna Kea, Hawaii, USA4,207 m (13,802 ft) above sea level

    They also could detect molecular oxygen in temperate terrestrial planets in transit around close and small stars, the report says.

    The committee pointed out that the technology road map to enable the full potential of GMT and TMT in the study of exoplanets is in need of investments, and should leverage the existing network of U.S. centers and laboratories. To that end, the report recommends that the National Science Foundation invest in both telescopes and their exoplanet instrumentation to provide all-sky access to the U.S. community.”

    And for another variety of ground-based observing the study called for the funding of a project to substantially increase the precision of instruments that find and measure exoplanets using the detected “wobble” of the host star. But stars are active with or without a nearby exoplanet, and so it has been difficult to achieve the precision that astronomers using this “radial velocity” technique need to find and characterize smaller exoplanets.

    Several smaller efforts increase this precision are under way in the U.S., and the European Southern Observatory has a much larger project in development.

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    While the NAS report gives a lot of attention to instruments and ways to use them, it also focuses as never before on astrobiology — the search for life beyond Earth.

    Much work has been done on how to determine whether life exists on a distant planet through modeling and theorizing about biosignatures. The report encourages scientists to expand that work and embraces it as a central aspect of exoplanet science.

    The study also argues that interdisciplinary science — bringing together researchers from many disciplines — is the necessary way forward. It highlights the role of the Nexus for Exoplanet System Science, a NASA initiative which since 2015 has brought together a limited but broad number of science teams from institutions across the country to learn about each other’s work and collaborate whenever possible.

    The initiative itself has not required much funding, instead bringing in teams that had been supported with other grants.

    But now, the NAS study recommends that “building on the NExSS model, NASA should support a cross-divisional exoplanet research coordination network that includes additional membership opportunities via dedicated proposal calls for interdisciplinary research.”

    The initiative, which I’m proud to say sponsors this column, would potentially grow during this process.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 10:10 am on July 25, 2018 Permalink | Reply
    Tags: , , , , Many Worlds, Water on Mars   

    From Many Worlds: “Large Reservoir of Liquid Water Found Deep Below the Surface of Mars” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-07-25
    Marc Kaufman

    1
    Artist impression of the Mars Express spacecraft probing the southern hemisphere of Mars, superimposed on a radar cross section of the southern polar layered deposits. The leftmost white line is the radar echo from the Martian surface, while the light blue spots are highlighted radar echoes along the bottom of the ice. Those highlighted areas measure very high reflectivity, interpreted as being caused by the presence of water. (ESA, INAF. Graphic rendering by Davide Coero Borga )

    ESA Mars Express

    Far beneath the frigid surface of the South Pole of Mars is probably the last place where you might expect the first large body of Martian liquid water would be found. It’s -170 F on the surface, there are no known geothermal sources that could warm the subterranean ice to make a meltwater lake, and the liquid water is calculated to be more than a mile below the surface.

    Yet signs of that liquid water are what a team of Italian scientists detected — a finding that they say strongly suggests that there are other underground lakes and streams below the surface of Mars. In a Science journal article released today, the scientists described the subterranean lake they found as being about 20 kilometers in diameter.

    The detection adds significantly to the long-studied and long-debated question of how much surface water was once on Mars, a subject that has major implications for the question of whether life ever existed on the planet.

    Finding the subterranean lake points to not only a wetter early Mars, said co-author Enrico Flamini of the Italian space agency, but also to a Mars that had a water cycle that collected and delivered the liquid water. That would mean the presence of clouds, rain, evaporation, rivers, lakes and water to seep through surface cracks and pool underground.

    Scientists have found many fossil waterways on Mars, minerals that can only be formed in the presence of water, and what might be the site of an ancient ocean.

    But in terms of liquid water now on the planet, the record is thin. Drops of water collected on the leg of NASA’s Phoenix Lander after it touched down in 2008, and what some have described as briny water appears to be flowing down some steep slopes in summertime. Called recurrent slope lineae or RSLs, they appear at numerous locations when the temperatures rise and disappear when they drop.

    This lake is different, however, and its detection is a major step forward in understanding the history of Mars.

    2
    Color photo mosaic of a portion of Planum Australe on Mars. The subsurface reflective echo power is color coded and deep blue corresponds to the strongest reflections, which are interpreted as being caused by the presence of water. (USGS Astrogeology Science Center, Arizona State University, INAF)

    The discovery was made analyzing echoes captured by the the radar instruments on the European Space Agency’s Mars Express, a satellite orbiting the planet since 2002. The data for this discovery was collected from observation made between 2012 and 2015.

    3
    A schematic of how scientists used radar to find what they interpret to be liquid water beneath the surface of Mars. (ESA)

    Antarctic researchers have long used radar on aircraft to search for lakes beneath the thick glaciers and ice layers, and have found several hundred. The largest is Lake Vostok, which is the sixth largest lake on Earth in terms of volume of water. And it is two miles below the coldest spot on Earth.

    So looking for a liquid lake below the southern pole of Mars wasn’t so peculiar after all. In fact, lead author Roberto Orosei of the Institute of Radioastronomy of Bologna, Italy said that it was the ability to detect subsurface water beneath the ice of Antarctica and Greenland that helped inspire the team to look at Mars.

    There are a number of ways to keep water liquid in the deep subsurface even when it is surrounded by ice. As described by the Italian team and an accompanying Science Perspective article by Anja Diez of the Norwegian Polar Institute, the enormous pressure of the ice lowers the freezing point of water substantially.

    Added to that pressure on Mars is the known presence of many salts, that the authors propose mix with the water to form a brine that lowers the freezing point further.

    So the conditions are present for additional lakes and streams on Mars. And according to Flamini, solar system exploration manager for the Italian space agency, the team is confident there are more and some of them larger than the one detected. Finding them, however, is a difficult process and may be beyond the capabilities of the radar equipment now orbiting Mars.

    3
    Subsurface lakes and rivers in Antarctica. Now at least one similar lake has been found under the southern polar region of Mars. (NASA/JPL)

    The view that subsurface water is present on Mars is hardly new. Stephen Clifford, for many years a staff scientist at the Lunar and Planetary Institute, even wrote in 1987 that there could be liquid water at the base of the Martian poles due to the kind of high pressure environments he had studied in Greenland and Antarctica.

    So you can imagine how gratifying it might be to learn, as he put it “of some evidence that shows that early theoretical work has some actual connection to reality.”

    He considers the new findings to be “persuasive, but not definitive” — needing confirmation with other instruments.

    Clifford’s wait has been long, indeed. Many observations by teams using myriad instruments over the years did not produce the results of the Italian team.

    Their discovery of liquid water is based on receiving particularly strong radar echoes from the base of the southern polar ice — echoes consistent with the higher radar reflectivity of water (as opposed to ice or rock.)

    After analyzing the data in some novels ways and going through the many possible explanations other than the presence of a lake, Orosei said that none fit the results they had. The explanation, then, was clear: “We have to conclude there is liquid water on Mars.”

    The depth of the lake — the distance from top to bottom — was impossible to measure, though the team concluded it was at least one meter and perhaps in the tens of meters.

    Might the lake be a habitable? Orosei said that because of the high salt levels “this is not a very pleasant environment for life.”

    But who knows? As he pointed out, Lake Vostok and other subglacial Antarctic lake, are known to be home to single-cell organisms that not only survive in their very salty world, but use the salt as part of their essential metabolism.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:02 am on July 9, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds   

    From Many Worlds: “The Architecture of Solar Systems” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2
    The architecture of planetary systems is an increasingly important factor to exoplanet scientists. This illustration shows the Kepler-11 system where the planets are all roughly the same size and their orbits spaced at roughly the same distances from each other. The the planets are, in the view of scientists involved with the study, “peas in a pod.” (NASA)

    Before the discovery of the first exoplanet that orbits a star like ours, 51 Pegasi b, the assumption of solar system scientists was that others planetary systems that might exist were likely to be like ours.

    1
    This artist’s view shows the hot Jupiter exoplanet 51 Pegasi b, sometimes referred to as Bellerophon, which orbits a star about 50 light-years from Earth in the northern constellation of Pegasus (The Winged Horse). This was the first exoplanet around a normal star to be found in 1995. Twenty years later this object was also the first exoplanet to be be directly detected spectroscopically in visible light. ESO/M. Kornmesser/Nick Risinger (skysurvey.org)

    Small rocky planets in the inner solar system, big gas giants like Jupiter, Saturn and Neptune beyond and, back then, Pluto bringing up the rear.

    But 51 Peg b broke every solar system rule imaginable. It was a giant and hot Jupiter-size planet, and it was so close to its star that it orbited in a little over four days. Our Jupiter takes twelve years to complete an orbit.

    This was the “everything we knew about solar systems is wrong” period, and twenty years later thinking about the nature and logic of solar system architecture remains very much in flux.

    But progress is being made, even if the results are sometimes quite confounding. The umbrella idea is no longer that solar, or planetary, systems are pretty much like ours, but rather that the galaxy is filled with a wild diversity of both planets and planetary systems.

    Detecting and trying to understand planetary systems is today an important focus 0f exoplanet study, especially now that the Kepler Space Telescope mission has made clear that multi-planet systems are common.

    As of early July, 632 multi planet systems have been detected and 2,841 stars are known to have at least one exoplanets. Many of those stars with a singular planet may well have others yet to be found.

    An intriguing newcomer to the diversity story came recently from University of Montreal astronomer Lauren Weiss, who with colleagues expanded on and studied some collected Kepler data.

    What she found has been deemed the “peas in a pod” addition to the solar system menagerie.

    Weiss was working with the California-Kepler Survey, which included a team of scientists pouring over, elaborating on and looking for patterns in, among other things, solar system architectures.

    Weiss is part of the California-Kepler Survey team, which used the Keck Observatory to obtain high-resolution spectra of 1305 stars hosting 2025 transiting planets originally discovered by Kepler.

    From these spectra, they measured precise sizes of the stars and their planets, looking for patterns in, among other things, solar system architectures. They focused on 909 planets belonging to 355 multi-planet systems. By improving the measurements of the radii of the stars, Weiss said, they were able to recalculate the radii of all the planets.

    So Weiss studied hundreds systems and did find a number of surprising, unexpected patterns.

    In many systems, the planets were all roughly the same size as the planet in orbit next to them. (No tiny-Mars-to-gigantic-Jupiter transitions.) This kind of planetary architecture was not found everywhere but it was quite common — more common than random planet sizing would predict.

    “The effect showed up with smaller planets and larger ones,” Weiss told me during last week’s University of Cambridge Exoplanets2 conference. “The planets in each system seemed to know about the sizes of the neighbors,” and for thus far unknown reasons maintained those similar sizes.

    What’s more, Weiss and her colleagues found that the orbits of these “planets in a pod” were generally an equal distance apart in “multi” of three planets or more. In other words, the distance between the orbits of planet A and planet B was often the same distance as between the orbits of planet B and planet C.

    So not only were many of the planets almost the same size, but they were in orbits spaced at distances from each other that were once again much more similar than a random distribution would predict. In the Astronomical Journal article where she and her colleagues described the phenomena, they also found a “wall” defining how close together the planets orbited.

    The architecture of these systems, Weiss said, reflected the shapes and sizes of the protoplanetary in which they were formed. And it would appear that the planets had not been disrupted by larger planets that can dramatically change the structure of a solar system — as happened with Jupiter in our own.

    But while those factors explain some of what was found, Weiss said other astrophysical dynamics needed to be at play as well to produce this common architecture. The stability of the system, for instance, would be compromised if the orbits were closer than that “wall,” as the gravitational pull of the planets would send them into orbits that would ultimately result in collisions.

    The improved spectra of the Kepler planets were obtained from 2011 to 2015, and the targets are mostly located between 1,000 and 4,000 light-years away from Earth.

    2
    The architectures of California-Kepler study multi-planet systems with four planets or more. Each row corresponds to the planets around one and the circles represent the radii of planets in the system. Note how many have lines of planets that are roughly the same size. (Lauren Weiss, The Astronomical Journal.)

    Planetary system architecture was a significant topic at the Cambridge Exoplanets2 conference. While the detection of individual exoplanets remains important in the field, it is often treated as a precursor to the ultimate detection of systems with more planets.

    The TRAPPIST-1 system, discovered in 2015 by a Belgian team, is probably the most studied and significant of those discovered so far.

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile


    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

    The ultra-cool dwarf star hosts seven Earth-sized, temperate exoplanets in or near the “habitable zone.” As described by one of those responsible for the discovery, Brice-Olivier Demory of the Center for Space and Habitability University of Bern, the system “represents a unique setting to study the formation and evolution of terrestrial planets that formed in the same protoplanetary disk.”

    The Trappist-1 architecture features not only the seven rocky planets, but also a resonance system whereby the planets orbits at paces directly related to the planets nearby them. In other words, one planet may make two orbits in exactly the time that it takes for the next planet to make three orbits.

    All the Trappist-1 planets are in resonance to another system planet, though they are not all in resonance to each other.

    The animation above from the NASA Ames Research Center shows the orbits of the Trappist-1 system. The planets pass so close to one another that gravitational interactions are significant, and to remain stable the orbital periods are nearly resonant. In the time the innermost planet completes eight orbits, the second, third, and fourth planets complete five, three, and two respectively.

    The system is very flat and compact. All seven of TRAPPIST-1’s planets orbit much closer to their star than Mercury orbits the sun. Except for TRAPPIST-1b, they orbit farther than the Galilean moons — three of which are also in resonance around Jupiter.

    The distance between the orbits of TRAPPIST-1b and TRAPPIST-1c is only 1.6 times the distance between the Earth and the Moon. A year on the closest planet passes in only 1.5 Earth days, while the seventh planet’s year passes in only 18.8 days.

    Given the packed nature of the system, the planets have to be in particular orbits that keep them from colliding. But they also have to be in orbits that ensure that all or most of the planets aren’t on the same side of the star, creating a severe imbalance that would result in chaos.

    “The Trappist-1 system has entered into a zone of stability,” Demory told me, also at the Exoplanets2 conference. “We think of it as a Darwinian effect — the system survives because of that stability created through the resonance. Without the stability, it would die.

    He said the Trappist-1 planets were most likely formed away from their star and migrated inward. The system had rather a long time to form, between seven and eight billion years.

    The nature of some of the systems now being discovered brings to mind that early reaction to the detection of 51 Pegasi b, the world’s first known exoplanet.

    The prevailing consensus that extra-solar systems would likely be similar to ours was turned on its head by the giant planet’s closeness to its host star. For a time many astronomers thought that hot Jupiter planets would be found to be common.

    But 20 years later they know that hot Jupiters — and the planetary architecture they create — are rather unusual, like the architecture of our own solar system.

    With each new discovery of a planetary system, the understanding grows that while solar systems are governed by astrophysical forces, they nonetheless come in all sizes and shapes. Diversity is what binds them together.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    About Many Worlds

    There are many worlds out there waiting to fire your imagination.

    Marc Kaufman is an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer, and is the author of two books on searching for life and planetary habitability. While the “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA’s NExSS initiative, any opinions expressed are the author’s alone.

    This site is for everyone interested in the burgeoning field of exoplanet detection and research, from the general public to scientists in the field. It will present columns, news stories and in-depth features, as well as the work of guest writers.

    About NExSS

    The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context — as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

     
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