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  • richardmitnick 11:48 am on January 13, 2020 Permalink | Reply
    Tags: , , , , Many Worlds, The reality of "Tatooine Worlds"   

    From Many Worlds: “Tatooine Worlds” 

    NASA NExSS bloc

    NASA NExSS

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    From Many Worlds

    January 13, 2020
    Marc Kaufman

    1
    Science fiction has become science. No habitable planets orbiting two suns like the fictional Tatooine have been detected so far, but more than a dozen “circumbinary planets” have been identified and many more are predicted. Exoplanets orbiting a host star that orbits its own companion star are even more common. (Lucasfilm)

    When the the first Star Wars movie came out in 1977, it featured the now-iconic two-sun, “circumbinary” planet Tatooine. At that time astronomers didn’t really know if such solar systems existed, with more than one sun and at least one planet.

    Indeed, the first extra-solar planet wasn’t detected until the early 1990s. And the first actual circumbinary planet was detected in 2005, and it was a Jupiter-size planet orbiting a system composed of a sun-like star and a brown dwarf. Tatooine was definitely not a Jupiter-size planet.

    But since then, the presence and distribution of circumbinaries has grown to a dozen and some the planets discovered orbiting the two stars have been smaller. The most recent discovery was announced this week and was made using the Transiting Exoplanet Survey Satellite (TESS) space telescope.

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The new planet, called TOI (TESS Object of Interest)-1338 b, is about 6.9 times larger than Earth. It orbits its pair of host stars every 95 days, while the stars themselves orbit each other in 15 days.

    As is common with binary stars, one is more massive and much brighter than the other (5976 K and 3657 K, respectively, with our sun at 5780 K), and as the planet orbits around it blocks some of the light from the brighter star.

    This transit allows astronomers to measure the size of the planet.

    Planet transit. NASA/Ames

    The transit — as scientific luck, or skill, would have it — was first found in the TESS data by a high school student working at NASA with over the summer, Wolf Cukier

    “I was looking through the data for everything the volunteers had flagged as an eclipsing binary, a system where two stars circle around each other and from our view eclipse each other every orbit,” Cukier said. “About three days into my internship, I saw a signal from a system called TOI 1338.”

    “At first I thought it was a stellar eclipse, but the timing was wrong. It turned out to be a planet.”

    With all of the data available from observations past and current, planet hunting clearly isn’t the scientific Wild West that it used to be — although the results remain often eye-popping and surprising.

    2
    An artist’s impression of TOI-1338b and its two host stars. (NASA’s Goddard Space Flight Center / Chris Smith)

    Although this most recent circumbinary finding features a planet much smaller than the first one discovered, it is probably gaseous and definitely not habitable, Cukier and his colleagues wrote. (They also presented their findings last week at the American Astronomical Union meeting in Hawaii.)

    But this doesn’t mean other planets orbiting two suns cannot be habitable.

    In 2017, a study in the journal Nature Communications concluded that a planet in a cirmumbinary system could have a habitable planet if it was the right distance from the two stars. It could even be a planet that would remain potentially habitable and wet for a long time.

    It turns out, such a planet could be quite hospitable if located at the right distance from its two stars, and wouldn’t necessarily even have deserts. In a particular range of distances from two sun-like host stars, an Earth-like planet covered in water would remain habitable and retain its water for a long time, according to the study.

    Max Popp, then an associate research scholar at Princeton University and Siegfried Eggl, a Caltech postdoctoral scholar at NASA’s Jet Propulsion Laboratory, created a model for a planet in the Kepler 35A and B binary star system.

    3
    The artistic rendition depicts the Kepler-35 planetary system. In the foreground, Kepler-35b, a Saturn-size world orbits its host stars every 131 days. The discovery of Kepler-34b and Kepler-35b establishes a new class of planets that orbit two stars, and suggests many millions of such systems exist in our galaxy. (NASA/ Mark A. Garlick / space-art.co.uk)

    In reality, the stellar pair Kepler 35A and B host a planet called Kepler 35b, a giant planet about eight times the size of Earth, with an orbit of 131.5 Earth days. For their study, researchers disregarded this planet and added a hypothetical water-covered, Earth-size planet around the Kepler 35 AB stars. They used a 3-D General Circulation Model and other tools to determine how this planet’s climate would behave as it orbited the host stars with orbital periods between 341 and 380 days.

    The results: “Double-star systems of the type studied here are excellent candidates to host habitable planets, despite the large variations in the amount of starlight hypothetical planets in such a system would receive,” said Popp, now at Sorbonne Université.

    This conclusion is based on the fact that the planet, if it had a sufficient concentration of CO2 in its atmosphere, could avoid falling into a complete frozen Snowball or a scalding Runaway Greenhouse state even though the binary stars make its path more complex. There are, of course, many more features beyond having liquid surface water that a planet needs to become habitable, but that is true of all exoplanets.

    Said Eggl, “We show that it’s worth targeting double-star systems. Our research is motivated by the fact that searching for potentially habitable planets requires a lot of effort, so it is good to know in advance where to look.”

    4
    These images show some of the exoplanet host stars with companion stars (B, C) that were found during the project. The images are composite images taken with the Panoramic Survey Telescope and Rapid Response System (PanSTARRS) .

    Pann-STARS 1 Telescope, U Hawaii, situated at Haleakala Observatories near the summit of Haleakala , on the island of Maui in Hawaii, USA, Pann-STARS 1 Telescope, U Hawaii, situated at Haleakala Observatories near the summit of Haleakala in Hawaii, USA, altitude 3,052 m (10,013 ft)altitude 3,052 m (10,013 ft)

    The image in the middle shows a hierarchical triple star system. (Mugrauer, PanSTARRS)

    The science of circumbinary planets, and planets in multi star systems, has been growing fast as scientists understand more about just how ubiquitous binary star systems are. Indeed, Indeed, some contend that all stars began as binaries and the single stars broke away as they evolved.

    While the number of circumbinary planets orbiting the two host stars is small as a percentage of the planets out there, the number of planets orbiting a star that also has a stellar companion is quite a bit larger. This is the conclusion of Markus Mugrauer of Friedrich Schiller University in Jena, Germany, in a 2019 article in the Monthly Notices of the Royal Astronomical Society.

    His study, using data from the European Gaia space telescope, led to the characterization (and sometimes discovery) of some 200 multiple star systems that contain exoplanets.

    ESA/GAIA satellite

    These are different from the circumbinary systems, which have what are termed P-type planets which usually have very wide orbits. Mugrauer studied S-type planets, where the exoplanet orbits only one of the binary (or triple) suns.

    But the survey does add to the understanding of stellar systems and their planets.

    “Multiple star systems are very common in our Milky Way,” explains Mugrauer. “If such systems include planets, they are of particular interest to astrophysics, because the planetary systems in them can differ from our solar system in fundamental ways.”

    The companion stars — which must be in rough equidistance with the exoplanet host stars — vary as to their mass, temperature and stage of evolution. The heaviest among them weigh 1.4 times more than our sun, while the lightest have only 8 per cent of the sun’s mass. Most of the companion stars are low-mass, cool dwarf stars that glow faintly red.

    However, eight white dwarfs were also identified among the faint stellar companions. A white dwarf is the burnt-out core of a sun-like star, which is only about as big as our Earth, but half as heavy as our sun. These observations show that exoplanets can indeed survive as intact bodies during the final evolutionary stage of a nearby sun-like star.

    5
    Diagram showing binary star system with “P-type” planets (which orbit both stars) and “S type” (which orbit only one star. (Wiki Commons)

    According to Mugrauer, S and P type planets are quite different astrophysically — in terms in terms of how they formed and their orbital and physical stability. While his focus is on S type planets and their stars, but told me that some of the planets he studied might actually be P type stars when more fully characterized.

    Stability is (not surprisingly) more complicated for planets in multi-star systems, and that’s why there appears to be many more multi-star systems in our galaxy without exoplanets than there are such systems with exoplanets.

    “It seems that planet formation in these systems is less likely and/or the stellar companions alter the orbits of the planets throughout their evolution,” he said. “That holds for close but also for wide stellar systems, but due to different mechanisms.”

    So while there may indeed be habitable planets à la Tatooine in binary and other multi star systems, they appear to be a limited subset of the multi star systems.

    But since astronomers estimate that up to half of the 100 billion stars in our galaxy are part of a binary system. that’s still a lot of binaries with planets one or both stars.

    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 January 2, 2020 Permalink | Reply
    Tags: "Using Climate Science on Earth to Understand Planets Beyond Earth", Anthony Del Genio retires., , , , , Many Worlds   

    From Many Worlds: “Using Climate Science on Earth to Understand Planets Beyond Earth” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    January 2, 2020
    Marc Kaufman

    1
    Climate expert Tony Del Genio has just retired after 41 years-plus at NASA’s Goddard Institute of Space Studies (GISS) in New York City. Here Del Genio is attending a Cubs game at Wrigley Field with (from the lower right) Dawn Gelino, Shawn Domogal-Goldman, Aaron Gronstal and Mary Voytek. All are part of the NASA NExSS initiative. (Dawn Gelino)

    Anthony Del Genio started out his career expecting to become first an engineer and then a geophysicist. He was in graduate school at UCLA and had been prepared by previous mentors to enter the geophysics field. But a 1973 department-wide test focused on seismology, rather than fields that he understood better, and his days as a geophysicist were suddenly over. Fortunately, one of his professors saw that he had done very well in the planetary atmospheres and geophysical fluid dynamics sections of the exams, and suggested a change in focus.

    That turned out to be a good thing for Del Genio, for the field of climate modeling, and for NASA. Because for the next four decades-plus, Del Genio has been an important figure in the field of climate science — first modeling cloud behavior and climate dynamics on Earth with ever more sophisticated atmospheric general circulation models (GCMs), and then beginning to do the same on planets beyond Earth.

    His entry into the world of Venus, Saturn, Titan and distant exoplanets beyond is how I met Tony in 2015. At the same time that Many Worlds began as a column, Del Genio was named one of the founding leaders of the Nexus for Exoplanet System Science (NExSS) — the pioneering, interdisciplinary NASA initiative to bring together scientists working in the field of planetary habitability. (NExSS also supports this column.)

    But first, a quote from Del Genio’s piece that sets the stage: “The beauty of science, if we are patient, is that nature reveals its secrets little by little, slowly enough to keep us pressing forward for more but fast enough for us not to despair.”

    Perspectives of Earth and Space Scientists2
    The NASA Nordberg award was presented to Del Genio in 2017, honoring his “vision, leadership, and accomplishments in Earth system processes.” His talk was was on the implications for climate change related from cloud feedback — the coupling between cloudiness and surface air temperature where a surface air temperature change leads to a change in clouds. (NASA/GSFC/Debora McCallum)

    The Perspectives excerpt begins when Del Genio is an established expert on the climate modelling of our planet, with a strong desire to use that knowledge in the burgeoning field of exoplanets:

    “At the 1984 NASA Division for Planetary Sciences meeting in Hawaii, I was introduced to Clyde Tombaugh, the discoverer of Pluto. This was one of the great thrills of my professional life—a once‐in‐a‐lifetime chance to meet someone who had discovered a planet. Of course, I was wrong on two fronts: Pluto is no longer a planet (which I hope is a temporary state of affairs—to a climate scientist, any relatively spherical object that can retain a nonnegligible atmosphere qualifies as a planet, even Titan), and little did I know then that I would later meet many people who had discovered planets.

    I had long been fascinated by the idea of life elsewhere in the universe—initially after being introduced to the Drake equation (a probabilistic equation for the number of technologically developed civilizations in the universe) by Shklovskii and Sagan’s Intelligent Life in the Universe (Shklovskii & Sagan, 1966) and later by Stephen Dole’s Habitable Planets for Man (Dole, 1964).

    Drake Equation, Frank Drake, Seti Institute


    Frank Drake with his Drake Equation. Credit Frank Drake

    3
    Intelligent Life in the Universe (Shklovskii & Sagan, 1966)

    5
    Habitable Planets for Man (Dole, 1964)

    I regarded these only as amusing thought experiments, though, so I took little notice when Wolszczan and Frail (1992) announced the first confirmed detection of planets orbiting a pulsar [AGU]—not candidates for life by any means.

    Exoplanet detections accelerated through the 1990s and 2000s, though, and with the advent of the Kepler mission and observations by ground‐based telescopes, we entered the age of actual, rather than imagined, rocky exoplanets with solid surfaces orbiting main sequence stars.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    To my great surprise, the question of whether we might someday discover life elsewhere had become real.

    My GISS colleague Nancy Kiang and NASA Goddard colleague Shawn Domagal‐Goldman were already thinking about this as members of the Virtual Planetary Laboratory team (of the University of Washington) that had been considering spectral signatures of life on other planets (“biosignatures”) for some time. They sensed that the time might be right for 3‐D climate models to be applied to the emerging problem of exoplanet habitability.

    5
    Del Genio, second to the left, and colleagues of the NASA ROCKE-3D NExSS team at their first team meeting at GISS in 2015. The ROCKE-3D general circulation model, an outgrowth of the parent GISS Earth GCM ModelE, is designed to study different climate conditions in the history of our own planet and other solar system terrestrial planets, as well as exoplanets. Del Genio was team leader for the effort.(NASA/GISS)

    They secured a bit of internal funding from Goddard to put together a small team, including me, to begin to generalize the GISS GCM to simulate planets other than Earth. (Columbia Astronomy colleagues Caleb Scharf and Kristen Menou and several of us at GISS had been unsuccessful at securing funding for this a decade earlier despite good reviews of our proposals.) In 2013 our group submitted a major proposal to NASA that included planetary scientists, astrophysicists, paleoclimate scientists, and several hybrid Earth climate‐planetary scientists (e.g., me) to address questions about the characteristics that might make a planet conducive to life.

    As luck would have it, NASA Astrobiology Program Manager Mary Voytek had been thinking for several years about new ways to break down the “stovepipes” that separated research in NASA’s Astrophysics, Planetary Science, Heliophysics, and Earth Science Divisions. Our proposal was selected, and Mary made us a founding member of a “research coordination network” (a concept borrowed from the National Science Foundation) that was given the name the Nexus for Exoplanet System Science (NExSS) https://nexss.info).

    Totaling 18 teams in its first iteration, and now up to 34, NExSS’ mandate is to bring together researchers in the four NASA science divisions to accelerate progress in the search for life elsewhere. In addition, I was asked, along with astrophysicists Natalie Batalha, the Kepler project scientist, and Dawn Gelino, now Deputy Director of the NASA Exoplanet Science Institute, to serve as co‐leads of NExSS, along with Shawn and NASA management postdoctoral fellow Andrew Rushby (named by Mary the “Jedi Council”). (Vikki Meadows, PI of the Virtual Planetary Laboratory, has recently joined the Jedi.) My double life as an Earth scientist and a planetary scientist had suddenly become marketable.

    What can an Earth scientist tell an astrophysicist that would be useful?

    Exoplanet astronomers are continually searching for an “Earth twin”—a planet similar to ours that would be a good candidate to host life. The real question though is how different a planet can be from Earth and still maintain liquid water on its surface, where it, and the life that it might support, could be detected from light years away.

    Put another way: What determines the surface temperature of a planet whose atmosphere contains different amounts of greenhouse gases, receives a different amount of sunlight, and so forth, than present‐day Earth does? This is actually the same question of forcings and feedbacks that I have studied for decades to understand 21st Century anthropogenic climate change but taken to extremes. Not surprisingly, then, what are some of the biggest uncertainties in assessing exoplanet habitability? Cloud (and water vapor and lapse rate and sea ice) feedbacks!

    Led by my GISS colleague Mike Way and with contributions from many others in the GISS Earth GCM group (Way et al., 2017), a generalized planetary version of the GISS GCM has been developed.We have used it to explore the possibility that ancient Venus under the faint young Sun may have been habitable (Way et al., 2016); to understand the processes that put excessive water vapor into the stratosphere as incident stellar flux increases, a precursor to the eventual loss of a planet’s oceans (Fujii et al., 2017); to determine how the thermal inertia and heat transport of a dynamic ocean might render a planet continuously habitable in the face of oscillations in planet eccentricity (Way & Georgakarakos, 2017); to examine scenarios for a possible habitable climate on the known exoplanet closest to Earth (Del Genio et al., 2019); to understand the transport of volatiles to permanently shadowed polar regions early in the moon’s history (Aleinov et al., 2019); to predict the planetary albedos and surface temperatures of exoplanets from sparse available information using Earth climate concepts (Del Genio, Kiang, et al., 2019); and to understand how high obliquity allows weakly illuminated planets to remain habitable (Colose et al., 2019).

    6
    The U.S. eastern seaboard as imaged by cameras on the International Space Station. With humans changing the Earth so rapidly, questions about how a habitable planet functions (or ceases to function) as a system have become more timely and pressing. Scientists including Del Genio look to other planets as well as our own for insights into what the future might hold. (NASA/ISS)

    On Earth we are now considered to be in a new epoch, the Anthropocene, in which humankind has become a leading order influence on the planet—in effect, turning Earth into a slightly different planet. In the new era of exoplanet science, formerly uncertain terms in the Drake equation such as the fraction of stars with planets are now observationally constrained—for example, most stars have planets! One of the biggest remaining uncertainties in the equation is the average lifetime of a technological civilization before it destroys itself or consumes all its energy sources.

    This is what thinking about other planets in addition to the Earth does. It takes one from wondering what the impacts of anthropogenic greenhouse gas increases will do to sea level, to extreme temperatures, to hurricane intensities, to regional drought in our lifetimes, and ups the ante to the larger question of whether in the long run our civilization will eventually figure things out and learn to sustain itself, or perish.

    As I near the end of my career, this opportunity to reflect upon it has made me more aware of lessons I have learned (mostly unintentionally) along the way:

    1/ Serendipity can have a great deal to do with the progression of a career. Many of us may have agonized about the direction we should follow in our careers when we were in school—I certainly did. My career has been anything but a straight line determined by my initial choices. Rather, it has been defined by a combination of failures, being in the right place at the right time, and openness to go in new directions. I have experienced one of the most remarkable periods in the history of science. I entered science about a decade after launch of the first Earth‐orbiting weather satellites and the first successful spacecraft missions to other planets, and I have witnessed visits to every planet in the solar system. I have been in science during the period of humanity’s awakening about anthropogenic climate change (unfortunate for humanity but a tremendous stimulus for more deeply understanding our own planet). Finally, I have seen the universe unveiled as the home of thousands (at least) of known planets orbiting other stars, and I was able to be a contributor to one of the earliest groups thinking about how to determine which of these might be good candidates to harbor life. My career has clearly been shaped by these external events.

    2/ Science is usually a team sport. The media tend to portray science using the paradigm of the heroic lone scientist, usually out in the field, gathering data, and experiencing that “eureka!” moment that immediately overturns an existing science paradigm. Perhaps that is sometimes true, but it has not been my own experience. Almost all my published papers were joint efforts with colleagues whose technical expertise and scientific insight complement my own. I hope that this essay is a suitable way to express my gratitude for how I have benefited from their talents. Some of my papers arose from data collected (by others) during field experiments, but most were modeling, theory, or remote sensing data analyses. And in fields as complex as the climates of Earth and other planets, paradigm overturning is usually a slow motion process—several of my more successful papers have been more highly cited in recent years than in the years that followed their publication.

    3/ Cross‐discipline research has made me a better scientist. I am often asked, “How does studying other planets help you understand Earth?” Although there are a few examples (Kahn, 1989), in general, the best way to understand Earth is to study Earth. The real value of studying both Earth and other planets is the perspective it has provided me on both. A foundation in Earth science helps one interpret observations of other planets, since much of the well‐explored physics of our own atmosphere can be applied to other planets. There are baroclinic eddies on Mars and Saturn, lightning storms due to water condensation on Jupiter and Saturn (and methane convective storms on Titan), and so on. But the relatively poorly observed planets of our Solar System and barely observed rocky exoplanets force us to ask basic, global questions and put our own planet in a larger context. In Earth science, we got caught up in the details so much a couple of decades ago that we largely stopped asking basic questions. In recent years, though, climate change has taught us that we do not understand Earth as well as we may have thought, and some scientists have begun once again to ask basic questions of our planet. These papers and others like them have effectively taken a planetary perspective on our own planet, to the betterment of our field. Exoplanet science has taken things a step further by placing the “small” number of planets in our solar system into the context of thousands of other planets. Given that large a sample, seemingly simple questions such as what determines whether a planet even has an atmosphere turn out to be much more fascinating than anticipated (e.g., Zahnle & Catling, 2017). Conversely, the history of habitability in our own solar system provides insights into processes that may be in play on exoplanets that we as yet know little about (Del Genio et al., 2019). This cross‐discipline fertilization is a trend I hope will continue.

    7
    Anthony Del Genio. (NASA/GISS)

    I do not like the idea of starting a book and not getting to read the final chapter. At this stage in my life, though, I have to accept that the questions of the ultimate fate of our society, and the discovery of life elsewhere in the universe (a matter of when, not if, I am certain), may or may not be answered while I am still around to experience them. But to have the chance to live a life in scientific research during a time that saw the beginning of human awareness about both the effect we have on our own planet and the likelihood of alien biospheres, along with the creation of tools to begin to understand them and great colleagues with whom to share the journey, is consolation enough. Still … wouldn’t it be great to get to read the final chapter?”

    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 12:58 pm on December 5, 2019 Permalink | Reply
    Tags: "Icy Moons and Their Plumes", , , , , , , Many Worlds, What is not at all common is liquid water   

    From Many Worlds: “Icy Moons and Their Plumes” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    December 5, 2019
    Marc Kaufman

    1
    The existence of water or water vapor plumes on Europa has been studied for years, with a consensus view that they do indeed exist. Now NASA scientists have their best evidence so far that the moon does sporadically send water vapor into its atmosphere. (NASA/ESA/K. Retherford/SWRI)

    Just about everything that scientists see as essential for extraterrestrial life — carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur and sources of energy — is now known to be pretty common in our solar system and beyond. It’s basically there for the taking by untold potential forms of life.

    But what is not at all common is liquid water. Without liquid water Earth might well be uninhabited and today’s Mars, which was long ago significantly wetter, warmer and demonstrably habitable, is widely believed to be uninhabited because of the apparent absence of surface water (and all that deadly radiation, too.)

    This is a major reason why the discovery of regular plumes of water vapor coming out of the southern pole of Saturn’s moon Enceladus has been hailed as such a promising scientific development.

    NASA’s Solar System Exploration. Color image of icy Enceladus, the sixth-largest moon of Saturn

    The moon is pretty small, but most scientists are convinced it does have an under-ice global ocean that feeds the plume and just might support biology that could be collected during a flyby.

    But the moon of greatest scientific interest is Europa, one of the largest that orbits Jupiter.

    2
    Varied terrain on Europa. Credit: NASA/JPL-Caltech/SETI Institute

    It is now confidently described as having a sub-surface ocean below its crust of ice and — going back to science fiction writer extraordinaire Arthur C. Clarke — has often been rated the most likely body in our solar system to harbor extraterrestrial life.

    That is why it is so important that years of studying Europa for watery plumes has now paid off. While earlier observations strongly suggested that sporadic plumes of water vapor were in the atmosphere, only last month was the finding nailed, as reported in the journal Nature Astronomy.

    “While scientists have not yet detected liquid water directly, we’ve found the next best thing: water in vapor form,” said Lucas Paganini, a NASA planetary scientist who led the water detection investigation.

    3
    As this cutaway shows, vents in Europa’s icy crust could allow plumes of water vapor to escape from a sub-surface ocean. If observed up close, the chemical components of the plumes would be identified and could help explain the nature and history of the ocean below. ( NASA)

    The amount of water vapor found in the European atmosphere wasn’t great — about an Olympic-sized pool worth of H2O. Looking at the moon from the W. M. Keck Observatory in Hawaii, the scientists saw water molecules on the side of Europa that’s always facing in the direction of the moon’s orbit around Jupiter.

    Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

    But Paganini’s team registered the faint signal of water vapor just once throughout 17 nights of observations between 2016 and 2017

    That fact, Paganini said in a release, was significant. “For me,” he said, “the interesting thing about this work is not only the first direct detection of water above Europa, but also the lack (of more plumes found) within the limits of our detection method.”

    More advanced detection equipment certainly might find much more water in the atmosphere, and that possibility is where Europa eclipses Enceladus as the icy moon most likely to give up some of its closest kept secrets in the near term.

    Because in the next five years or so, not one but two major missions are scheduled to head for Europa — NASA’s Europa Clipper and the European Space Agency-led JUpiter ICy moons Explorer mission (JUICE.)

    NASA/Europa Clipper annotated

    ESA/Juice spacecraft depiction


    How the JUICE spacecraft will fly to the Jupiter system, using five gravity boosts along the way. (ESA)

    Although several missions have been proposed to return to Enceladus with more specialized instruments than the Cassini spacecraft had when it flew through a plumes in 2015, none have been formally approved and funded.

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    JUICE is scheduled to launch first to Europa — as early as 2022. Because it will need multiple gravity boosts from other bodies to reach the Jupiter system, it is not expected to arrive before the late 2020s.

    As for the Europa Clipper, the launch date remains uncertain but estimated to be in the mid 2020s. If it can use the NASA’s super-heavy Space Launch System (SLS) for its launch, it could reach Jupiter and Europa before JUICE. But because of endless delays with the SLS development, and the desire to use its unique lift power if and when it becomes available for launches to our moon and elsewhere, the Clipper may well launch on a commercial rocket and need the same time-consuming boosts.

    The Europa Clipper and JUICE missions are different in many ways, but they do have the same Jupiter system and Europa destinations and so are in a race of sorts to be the first to taste Europa’s atmosphere up close.

    It’s a cooperative race for sure — NASA does have an instrument planned to ride on the JUICE mission — but who gets there first will be of some space-faring importance just because Europa has long been such a promising destination for scientists.

    Some Europa background:

    Forty years ago, a Voyager spacecraft snapped the first closeup images of Europa, one of Jupiter’s 79 moons.

    NASA/Voyager 2

    These revealed brownish cracks slicing the moon’s icy surface, which give Europa the look of an eyeball with criss-crossing veins. Missions to the outer solar system in the decades since have amassed enough additional information about Europa to make it a high-priority target of investigation in NASA’s search for life.

    For instance, NASA’s Galileo spacecraft, measured perturbations in Jupiter’s magnetic field near Europa while orbiting the gas giant planet.

    NASA/Galileo 1989-2003

    The measurements, taken between 1995 and 2003, suggested to scientists that electrically conductive fluid, likely a salty ocean beneath Europa’s ice layer, was causing the magnetic disturbances. When researchers analyzed the magnetic disturbances more closely in 2018, they found evidence of possible plumes.

    In the meantime, scientists announced in 2013 that they had used NASA’s Hubble Space Telescope to detect the chemical elements hydrogen (H) and oxygen (O) — components of water (H2O) — in plume-like configurations in Europa’s atmosphere. And a few years later, other scientists used Hubble to gather more evidence of possible plume eruptions when they snapped photos of finger-like projections that appeared in silhouette as the moon passed in front of Jupiter.

    Lorenz Roth, an astronomer and physicist from KTH Royal Institute of Technology in Stockholm who led the 2013 Hubble study and was a co-author of this recent investigation, said that detecting water vapor on other worlds is especially challenging.

    Existing spacecraft have limited capabilities to detect it, he said, and scientists using ground-based telescopes to look for water in deep space have to account for the distorting effect of water in Earth’s atmosphere. To minimize this effect, Paganini’s team used complex mathematical and computer modeling to simulate the conditions of Earth’s atmosphere so they could differentiate Earth’s atmospheric water from Europa’s in data returned by the Keck spectrograph.

    KECK Echellette Spectrograph and Imager (ESI)

    They used a spectrograph at the Keck Observatory that measures the chemical composition of planetary atmospheres through the infrared light they emit or absorb. Molecules such as water emit specific frequencies of infrared light as they interact with solar radiation.

    So while scientists had evidence that key ingredients for life, including liquid water, were present under Europa’s icy surface and that liquid geysers might sometimes erupt into the atmosphere, nobody had fully confirmed the presence of water in these plumes by directly measuring the water molecule itself. Until, that is, the recent confirmation by by scientists at NASA’s Goddard Space Flight Center and their international partners.

    The recent finding of a plume of water vapor in the Europan atmosphere will help scientists better understand the inner workings of the moon. Any lingering doubts have been alleviated about the presence of a liquid water ocean, possibly twice as large as Earth’s, beneath this moon’s miles-thick ice shell. And clearly and importantly, conditions in the ocean would have to be changeable, in some flux, if water is periodically pushed up to the surface and into the atmosphere.

    There are, of course, other theories of the source of the Europa plumes. Another is that that the water and vapor comes from shallow reservoirs of melted water ice not far below Europa’s surface. It’s also possible that Jupiter’s strong radiation field is stripping water particles from Europa’s ice shell, though the recent investigation argued against this mechanism as the source of the observed water.

    As Avi Mandell, a Goddard planetary scientist on Paganini’s team, put it:. “Eventually, we’ll have to get closer to Europa to see what’s really going on.”

    So if Europa is getting all this attention, why are there no parallel big missions planned to Enceladus? After all, the plumes (or geysers) coming out of the moon are known to be consistent and substantial.

    One mission was proposed for last year’s NASA New Frontiers class competition and was well received but ultimately not selected. The German Space Agency has been studying an Enceladus mission since 2012 and Breakthrough Initiative founder Yuri Milner, a Russian billionaire living in the United States, is working with a small NASA team on an simple, relatively inexpensive spacecraft to fly again through the plume and test for organic compounds and possibly by-products of biology.

    In effect, Milner and his colleagues believe the possibility of finding life on Enceladus is scientifically too tempting to wait for a full NASA effort — which appears unlikely while the costly Europa Clipper mission is under development.

    Briefly, the Enceladus geysers — which sometimes form a curtain of vapor –erupt from the moon’s south polar region. They were first interpreted as being the result of tidally produced pressure and heat in a subterranean sea, with fissures in the ice allowing the water and water vapor to escape. More recently, an even more intriguing source of the needed heat has been proposed.

    In 2017, an article in the journal Science by J. Hunter Waite of the Southwest Research Institute et al reported that measurements taken during Cassini mission’s final fly-through captured the presence of molecular hydrogen in the plumes. To planetary and Earth scientists, that particular hydrogen presence quite clearly means that the water shooting out from Enceladus is coming from an interaction between water and warmed rock minerals at the bottom of the moon’s ocean– and possibly from within hydrothermal vents.

    These chimney-like vents at the bottom of our oceans — coupled with a chemical mixture of elements and organic compounds similar to what has been detected in the plumes — are known on Earth as prime breeding grounds for life. One important reason why is that the hydrogen and hydrogen compounds produced in these settings are a source of energy, or food, for microbes.

    A logical conclusion of these findings: the odds that Enceladus harbors forms of simple life increased with the finding, though remain impossible to quantify.

    Less is known about the composition of the apparently far more sporadic plumes of Europa, but JUICE and the Europa Clipper will — if they arrive successfully — change that. They too may find a chemical soup conducive to life, and similar signs of deep ocean interactions between the salty ocean and rock minerals heated hydrothermally, through radiation, tidal pressures or perhaps all of the above.

    And, no doubt, the precious water and water vapor in those plumes will be the gateway to their understandings.

    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 11:03 am on November 7, 2019 Permalink | Reply
    Tags: "A Southern Sky Extravaganza From TESS", , , , , Many Worlds,   

    From Many Worlds: “A Southern Sky Extravaganza From TESS” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    November 7, 2019
    Marc Kaufman

    NASA/MIT TESS replaced Kepler in search for exoplanets

    1
    Candidate exoplanets as seen by TESS in a southern sky mosaic from 13 observing sectors. (NASA/MIT/TESS)

    NASA’s Transiting Exoplanet Survey Satellite (TESS) has finished its one year full-sky observation of Southern sky and has found hundreds of candidate exoplanets and 29 confirmed planets.

    _________________________________________________________
    TESS searches with the Planet Transit method, the same method used so well and for so long by Kepler.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    Planet transit. NASA/Ames

    _________________________________________________________

    It is now maneuvering its array of wide-field telescopes and cameras to focus on the northern sky to do the same kind of exploration.

    At this turning point, NASA and the Massachusetts Institute of Technology — which played a major role in designing and now operating the mission — have put together mosaic images from the first year’s observations, and they are quite something.

    Constructed from 208 TESS images taken during the mission’s first year of science operations, these images are a unique space-based look at the entire Southern sky — including the Milky Way seen edgewise, the Large and Small Magellenic galaxies, and other large stars already known to have exoplanets.

    “Analysis of TESS data focuses on individual stars and planets one at a time, but I wanted to step back and highlight everything at once, really emphasizing the spectacular view TESS gives us of the entire sky,” said Ethan Kruse, a NASA Postdoctoral Program Fellow who assembled the mosaic at NASA’s Goddard Space Flight Center.

    2
    Overlaying the figures of selected constellations helps clarify the scale of the TESS southern mosaic. TESS has discovered 29 exoplanets, or worlds beyond our solar system, and more than 1,000 candidate planets astronomers are now investigating. NASA/MIT/TESS

    The mission is designed to vastly increase the number of known exoplanets, which are now theorized to orbit all — or most — stars in the sky.

    TESS searches for the nearest and brightest main sequence stars hosting transiting exoplanets, which are the most favorable targets for detailed investigations.

    While previous sky surveys with ground-based telescopes have mainly detected giant exoplanets, TESS will find many small planets around the nearest stars in the sky. The mission will also provide prime targets for further characterization by the James Webb Space Telescope, as well as other large ground-based and space-based telescopes of the future.

    The TESS observatory uses an array of wide-field cameras to perform a survey of 85% of the sky. With the satellite observatory, it is possible to study the mass, size, density and orbit of a large cohort of small planets, including a sample of rocky planets in the habitable zones of their host stars.

    Using the known planet size, orbit and mass, TESS and ground-based follow-up will be able to determine the planets’ compositions. This will reveal whether the planets are rocky (like Earth), gas giants (like Jupiter) or something even more unusual. Additional follow-up with ground- and space-based observatories , will also allow astronomers to study the atmospheres of many of these planets.

    Here is a NASA video describing the images further, zooming in more closely on some particularly interesting features.


    Credits: NASA’s Goddard Space Flight Center Francis Reddy (University of Maryland College Park): Lead Science Writer Claire Andreoli (NASA/GSFC): Public Affairs Officer Scott Wiessinger (USRA): Lead Producer Scott Wiessinger (USRA): Editor Barb Mattson (University of Maryland College Park): Narrator Ethan Kruse (USRA): Visualizer.

    TESS is designed to survey 200,000 of the brightest stars nearest to our sun. Of the thousands of planet candidates to be identified, approximately 300 are expected to be Earth-sized and super-Earth-sized exoplanets, which are worlds no larger than twice the size of Earth.

    TESS is searching for stars 30 to 100 times brighter than those the pioneering Kepler Space Telescope mission and K2 follow-up surveyed from 2009 to 2018. TESS will cover a sky area 400 times larger than that monitored by Kepler, which intentionally stared at a small section of the sky to make it’s census.

    The satellite was launched on April 18, 2018 aboard a SpaceX Falcon 9 rocket. It’s primary mission is to observe for two years, but these missions often last considerably longer.

    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 10:00 am on October 30, 2019 Permalink | Reply
    Tags: "A Telling Nobel Exoplanet Faux Pas", Many Worlds, Michel Mayor of the University of Geneva and Didier Queloz of the the University of Cambridge had won the Nobel for physics to honor their work in detecting that first exoplanet., Rather it was the work of a team led by Geoffrey Marcy and Paul Butler — the San Francisco State University group that confirmed the existence of the hot Jupiter exoplanet 51 Pegasi b., The graph presented at the Nobel award shows the curve from the Lick Observatory in California that an American team had produced to confirm the initial finding of the first exoplanet 51 Pegasi b., The interweaving of the work of the Swiss and the American teams searching for the first exoplanet orbiting a sun-like star., This is embarrassing. But it also indirectly points to one of the realities that the Nobel Committee is forced by the will of Alfred Nobel to ignore: science is seldom the work of but two or three peo   

    From Many Worlds: “A Telling Nobel Exoplanet Faux Pas” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    October 30, 2019
    Marc Kaufman

    1
    This is the Doppler velocity curve displayed by the Nobel Committee to illustrate what Mayor and Queloz had accomplished in 1995. But actually, the graph shows the curve from the Lick Observatory in California that an American team had produced to confirm the initial finding. Such was the interweaving of the work of the Swiss and the American teams searching for the first exoplanet orbiting a sun-like star. (Image courtesy of Geoff Marcy and Paul Butler, San Francisco State University)

    Given the complex history of the discovery and announcement in 1995 of the first exoplanet that orbits a sun-like star, it is perhaps no surprise that errors might sneak into the retelling. Two main groups were racing to be first, and for a variety of reasons the discovery ended up being confirmed before it was formally announced.

    A confusing situation prone to mistakes if all involved aren’t entirely conversant with the details. But an error — tantamount to scientific plagiarism — by the Nobel Committee? That is a surprise.

    The faux pas occurred at the announcement on October 8 that Michel Mayor of the University of Geneva and Didier Queloz of the the University of Cambridge had won the Nobel for physics to honor their work in detecting that first exoplanet orbiting a sun-like star.

    As Nobel Committee member Ulf Danielsson described the achievement, a powerpoint display of important moments and scientific findings in their quest was displayed on a screen behind him.

    When the ultimate image was on deck to be shown — an image that presented the Doppler velocity curve that was described as the key to the discovery — the speaker appeared to hesitate after looking down to see what was coming next.

    If he did hesitate, it was perhaps because to those in the know, the curve did not come from Mayor and Queloz.

    Rather, it was the work of a team led by Geoffrey Marcy and Paul Butler — the San Francisco State University group that confirmed the existence of the hot Jupiter exoplanet 51 Pegasi b several days after the discovery was made public (to some considerable controversy) at a stellar systems conference in Florence. So at a most significant juncture of the Nobel introduction of the great work of Mayor and Queloz, hard-won data by a different team was presented as part of the duo’s achievement.

    This is both awkward and embarrassing, but it also indirectly points to one of the realities that the Nobel Committee is forced, by the will of Alfred Nobel, to ignore: That science is seldom the work now of but two or three people.

    The Nobel Committee can award only three Nobels per category, but the scientific advances that led to the Mayor-Queloz discovery were part of a much larger enterprise, as is the case with most major science advances. And what began in the mid 1990s with 51 Pegasi b has blossomed spectacularly with the ingenuity and hard work of thousands of other exoplanet scientists.

    2
    Paul Butler (left) and Geoffrey Marcy at San Francisco State in the time after their confirmation of 51 Pegasi b and their discovery of many of the next generation of exoplanets.

    Why does this faux pas matter?

    One reason, in my view, is that the contribution of the American team has at times gotten quite lost in the telling of the 51 Pegasi b story. Their work is mentioned in the Nobel citation for sure, but that is pretty thin gruel. (The race between the Swiss and American teams to find the first exoplanet orbiting a sun-like star is described in a Many Worlds column written soon after the Mayor/Queloz Nobel was announced.)

    There are many reasons for this. One for sure is that in 2015 the high-profile Marcy was booted out of the University of California, Berkeley astronomy department and off prestigious boards and scientific collaborations because of numerous accusations of sexual harassment during his career determined to be well-founded.

    Some ten years before that happened, Butler, as well as master spectrometer builder Steven Vogt and others from their original team, had broken bitterly with Marcy over different issues. Butler was already a staff scientist at the Carnegie Institution for Science in Washington, from which year after year he has traveled to Chile, Hawaii, Australia and more to spend his nights searching for more planets. He has found hundreds of them and has worked with promising young astronomers to make some of the major exoplanet discoveries of the 2010s.

    Several years ago, Butler wrote the history of his early days as a planet hunter, with a detailed description of the science (and drama) of the first discovery and confirmation. Is was published on the Pale Red Dot website set up by astronomer Guillem Anglada-Escudé, who in recent years played a leading role on the teams that found the two exoplanets closest to Earth — Proxima Centauri b and Barnard’s star. Butler is a co-author on both of those papers.

    4
    ‘A brief personal History of Exoplanets’, by Paul Butler

    by R. Paul Butler, Staff Scientist at the Carnegie Institution for Science Prologue “I began working on exoplanets in 1986. At the time there were no known planets beyond the solar system. An exoplanet meeting could have been held in a phone booth, of which there were still many. When asked by other astronomers, “What … Continue reading

    If you look at the Pale Red Dot article, you will see well into the text a key graph that Butler and Marcy produced to confirm the initial Mayor/Queloz discovery. This is the graph:

    5
    This is the caption to the above graph, by all appearances the one used by the Nobel Committee in the announcement of the Mayor/Queloz prize. “Doppler measurements of 51 Peg from observations were made at Lick Observatory between Oct.11, 1995 and Dec. 1996.” (Courtesy Geoff Marcy and Paul Butler, San Francisco State University.)

    In full disclosure, I have written in the past about Butler’s work and I consider him to be a friend. But he is not the one who identified this Nobel misidentification. (Butler later wrote to me from the Las Campanas Observatory in Chile that the Nobel announcement had nothing to do with him and so he knew nothing about it.)

    It was rather another member of that original Bay area group, then doctoral student and now San Francisco State University adjunct assistant professor of astronomy and physics Christopher McCarthy, who noticed the misidentification. He had seen the video of the Nobel announcement and saw what seemed to be a very familiar graph displayed during the presentation.

    When I contacted him, this is what McCarthy wrote to me:

    “In fact, these data were not obtained by those who received the prize but by Marcy & Butler at Lick Observatory. I know this because this image has the format that all our data plots had in those days, with the best fitting values for P,K and e in the upper left with the RMS scatter in the upper right…”

    He sent this link to an article posted on the then brand-new Worldwide Web in the aftermath of the 51 Pegasi b discovery: http://exoplanets.org/no51pegb.html

    The graph is present on the link, which includes a description of how Marcy and Butler teamed up with Mayor and Queloz to fight back against broad scientific critiques of their respective team’s exoplanet work at that time.

    “Ironically,” McCarthy wrote, “the problem of misappropriation of data happened early on, and after the image shown above first began to be credited to Michael & Didier. Thereafter all subsequent public data images were tagged with ‘Marcy & Butler’ on the image to avoid this confusion. But somehow this first, unlabeled image has remained around all these years to be misidentified again.”

    The graph is definitely not from the Swiss team, he wrote. “All their graphs were black & white back then with the Greek letter φ for phase as the x-axis label.”

    6
    Didier Queloz and Michel Mayor, Nobel Prize winner in Physics 2019 © UNIGE

    “For many years I have wondered how the Nobels would handle exoplanets. If the goal is to recognize contributions to the field then the award should clearly go to Geoff and Paul (who found 70% of the first hundred planets) as well as Mayor & Queloz. However Nobels can only go to three people, max, according to Alfred Nobel’s will. Up until 2015 I thought the award would go to Geoff & Michael. However, at this point in time, it would be hard for the Nobels to recognize Geoff without sending a clear message condoning sexual harassment. In principle, they could have included Paul as the 3rd person.”

    “They seem to have narrowed the usual scope from rewarding large contributions to a field of research to rewarding one single discovery….one paper. That’s very unusual for the Nobels but it does give them a way to recognize the importance of exoplanet research.”

    I contacted the Nobel Committee for comment about the graph mixup and Mats Larsson, Chair of the Nobel Committee for Physics wrote back to say that the radial velocity curve used in the press conference was indeed Marcy and Butler’s, and he explained the convoluted path of how it got there. He wrote that “By mistake, the (Marcy/Butler) radial velocity graph made its way into the press conference, which is unfortunate.”

    It was unfortunate, but it also reflects the reality that prizes to individuals in high-profile science tend to distort what actually happened. Not only are there supporting team members often making essential contributions, but there is also a scientific backdrop that informs, inspires and leads the field forward.

    And taking the argument a step further, there’s a burgeoning community of exoplanet scientists that, since the discovery of 51 Pegasi b, has advanced the field at warp speed. Mayor and Queloz deserve to be honored for sure, but it’s the larger community that has done something remarkable.

    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 2:09 pm on September 3, 2019 Permalink | Reply
    Tags: , , , , Cyanobacteria was responsible for the build-up of oxygen in the Earth’s atmosphere and the subsequent Great Oxidation Event about 2.5 billion years ago., If the film of life were replayed from very early days would it come out the same?, Many Worlds, Paleogenomics-the emerging field explores ancient life and ancient Earth by focusing on genetic material from ancient organisms preserved in today’s organisms, The goals are ambitious: To understand both the early evolution and the origins of life as well as to provide a base of knowledge about likely characteristics of potential life on other planets., The molecular clock is figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged., They ask the question of whether and how the expression of those genes — all important biomolecules generally involved in allowing a cell to operate smoothly — has changed over the eons., We build on modern biology- the existing genes- and use what we know from them to construct a molecular tree of life and come up with the ancestral genes of currently existing proteins., What we do is treat DNA as a fossil a vehicle to travel back in time   

    From Many Worlds: “Exploring Early Earth by Using DNA As A Fossil” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    September 3, 2019
    Marc Kaufman

    1
    Betül Kaçar is an assistant professor at the University of Arizona, and a pioneer in the field of paleogenomics — using genetic material to dive back deep into the ancestry of important compounds. (University of Arizona)

    Paleontology has for centuries worked to understand the distant past by digging up fossilized remains and analyzing how and why they fit into the evolutionary picture. The results have been impressive.

    But they have been limited. The evolutionary picture painted relies largely on the discovery of once hard-bodied organisms, with a smattering of iconic finds of soft-bodied creatures.

    In recent years, however, a new approach to understanding the biological evolution of life has evolved under the umbrella discipline of paleogenomics. The emerging field explores ancient life and ancient Earth by focusing on genetic material from ancient organisms preserved in today’s organisms.

    These genes can be studied on their own or can be synthetically placed into today’s living organisms to see if, and how, they change behavior.

    The goals are ambitious: To help understand both the early evolution and even the origins of life, as well as to provide a base of knowledge about likely characteristics of potential life on other planets or moons.

    “What we do is treat DNA as a fossil, a vehicle to travel back in time,” said Betül Kaçar, an assistant professor at the University of Arizona with more than a decade of experience in the field, often sponsored by the NASA Astrobiology Program and the John Templeton Foundation. “We build on modern biology, the existing genes, and use what we know from them to construct a molecular tree of life and come up with the ancestral genes of currently existing proteins.”

    And then they ask the question of whether and how the expression of those genes — all important biomolecules generally involved in allowing a cell to operate smoothly — has changed over the eons. It’s a variation on one the basic questions of evolution: If the film of life were replayed from very early days, would it come out the same?

    3
    Cyanobacteria, which was responsible for the build-up of oxygen in the Earth’s atmosphere and the subsequent Great Oxidation Event about 2.5 billion years ago. Kaçar studies and replaces key enzymes in the cyanobacteria in her effort to learn how those ancestral proteins may have behaved when compared to the same molecules today.

    The possibility of such research — of taking what is existing today and reconstructing ancient sequences from it — was first proposed by Emile Zuckerkandl, a biologist known for his work in the 1960s with Linus Pauling on the hypothesis of the “molecular clock.” The molecular clock is figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged.

    It would not be until decades later that technology and understandings had reached the point where the ideas could become working science. And as Kaçar makes clear, the effort remains a work in progress.

    Kaçar is perhaps best known for her work on the RuBisCO enzyme, which is present in plant chloroplasts and is involved in fixing atmospheric carbon dioxide during photosynthesis and producing oxygen. Since life’s origins on Earth, enzymes have been the primary mediators of the chemical reactions inside cells that make life as we know it possible.

    This catalyzing of the chemical reaction by which inorganic carbon enters the biological world — processed into sugars and other nutrient-rich compounds — has played an especially central role in the history of life on Earth. It is also often described as the most abundant enzyme on the planet.

    Kaçar and her teams compare RuBisCO (and other) gene sequences from modern organisms to infer what the sequence must have been in their common ancestor. By doing that many, many times, she says, “we follow back the branches of the evolutionary tree”.

    During her time at the NASA Astrobiology Institute as a postdoctoral fellow she developed a system to engineer microbial genomes with synthetic ancient genes [mBio], following the path of that inferred RuBisCO tree of life. The protein-producing gene in the modern genomes of an organism such as cyanobacteria can be replaced with an engineered ancestral gene that would have been present perhaps 2.5 billions of years ago, before the rise of oxygen on our planet.

    Experiments like this were ongoing when I visited her lab in Tucson earlier this year.

    The results: so far, some of the bacteria given the ancestral genes die but some survive while operating more slowly than today’s genes.

    That reduced reaction speed — seemingly related not so much to later mutations but to the amount of the enzyme produced by the engineered genome — may have been a feature of the early RuBisCO enzyme, Kaçar said.

    3
    Scientists trace the points in time where RuBisCO branched out in diverse forms, before and after the Great Oxidation Event. (B. Kaçar)

    The field of paleogenomics, and its search for ancestral forms of important current biomolecules, is growing fast.

    “When I first began this work about 10 years ago, I had to painstakingly explain prior foundational ideas by people like Zuckerkandl, just to introduce the basic concept, because people would say, ‘You wanna do what now?’” Kaçar told me.

    “Today, people are trying this approach across all different areas of biology and this is great news. For example, I just read about a recent effort to reconstruct and resurrect an ancient ferredoxin–a critical enzyme in shuttling electrons around in metabolism. So the idea is now big enough that others are using the same techniques for their own research interests and questions.”

    Kaçar said that her research team has a broad scope. They work on the translation machinery, whereby a cell “reads” the information in a messenger RNA and uses it to build a proteins (which played a crucial role in visualizing the tree of life); on basic metabolism with enzymes like RuBisCO and nitrogenase, and on biosignatures by looking at photosensitive pigments such as rhodopsons.

    “I like that we’re trying to cover many basic biological functions and learning along the way what can or cannot and what ought or ought not be done in developing these techniques.

    “We rolled up our sleeves, we have big dreams, the energy and the time. We hope to get there. We are working to get there.”

    But the work does have challenges. One is that the ancient rock record biosignatures that Kaçar and her colleagues are looking for — generally different carbon isotopes — may not precisely match the biosignatures left by the enzyme with engineered ancestral genes.

    Also, as Kaçar explained, there is little that is “systemically transferable between vastly different ancient molecules.”

    “Each mathematical effort to infer what the ancient sequences of a given gene is its own unique undertaking,” she said, “And the model outputs have to be interpreted on their own basis: i.e., is the signal into the deep past good? how far back does the signal reliably go? what is the probability that the inferred sequence will actually be functional?

    “In turn, each effort to engineer a genome with an inferred ancient component has to be undertaken on its own merits and may have its own difficulties.”

    4
    A graphic presentation of Kaçar’s work in reconstructing ancestral genomes. From a paper authored by Kaçar and colleague Amanda Garcia titled How to resurrect ancestral proteins as proxies for ancient biogeochemistry in Science Direct.

    Kaçar’s work is about as interdisciplinary as could be, bringing together evolutionary biologists and geologists, computer scientists and synthetic biologists, astrobiologists and astronomers. It has also led to her association with, among other organizations, the Earth-Life Science Institute in Tokyo, which focuses on the origins of life.

    The implications for origins of life and molecular evolutionary research are pretty clear, but she wants to take the work with ancestral genes and biomolecules further.

    “I aim to provide insights into the biology of the past and then tie this knowledge to our search for life in the universe,” she said during a recent Public Library of Science (PLOS) interview.

    “A planet free from life today, doesn’t necessary indicate a planet that never hosted life and to understand whether if this was the case, we need to have more than one instance of life to serve as a basis of comparison.

    “Earth’s past provides us alternative scenarios. Travel to about 4 billion years ago, what might greet you is a hot, vigorous planet with giant lava volcanoes, no major continents and lots of meteorite impacts.

    But we think life, with ecologies different from what is familiar to us today, probably existed back then too.” Surprisingly, however, “molecules of these life forms, however, were close to the fundamental molecules of life today.”

    A team at the University of Regensburg in Germany, for instance, found a reconstructed bacteria enzyme they were studying was quite similar to what would have been present 3.4 billion years ago.

    5
    NASA has played a significant role in Kaçar’s life. After graduating from Emory University’s School of Medicine and Chemistry with a PhD in Bio-Molecular Chemistry, she changed her focus to the study of evolution and won a grant from NASA’s Astrobiology Institute. She later won a grant from the NASA Exobiology program. and most recently the NASA Early Career Fellowship.

    Many scientists travel unexpected and intriguing personal paths on the way to their research, and Kaçar is certainly an example of that.

    Her family was initially from the Black Sea region of Turkey, where many women are known to be “gözü kara,” which translates from Turkish, Kaçar said, as having a perhaps unwise state of fearlessness. No women in her family had graduated from high school.

    Kaçar was born in Istanbul. As she remembers well, while in third grade her father sat her down and told her he couldn’t help anymore with her schoolwork because he had left school after second grade. But he encouraged her to get an education and to become an independent (and fearless) person.

    While studying chemistry as an undergraduate at Marmara University in Istanbul, she volunteered to be a real-time translator for a visiting group of scientists who had become to discuss protein biochemistry — especially as it relates to Alzheimer’s and Parkinson’s Diseases.

    One talk in particular fascinated her. It was on the molecular properties of an enzyme whose activity changes with age. She says she will never forget that first time she learned that when the site of a protein changes, entire cellular and bodily activities can collapse.

    She was “hooked” and reached out to one of the American professors who had been in the group. He suggested that she apply for a Howard Hughes Medical Institute summer undergraduate research scholarship, which she did and won one. That brought her to Atlanta and Emory University, where she visited his laboratory to study a particular protein . This was her first time in the U.S. or in a scientific research laboratory. In 2004, I came back to the same laboratory as a graduate student. She was 20 years old and didn’t know anyone outside the lab.

    In the following years she won a NASA research grant, taught and researched at Harvard University, won her current position at UA and, last year gave birth to a son. Kaçar is an accomplished public speaker as well, dedicated to bringing science to people.

    And all the while, she is working to solve major scientific problems in a burgeoning but exacting discipline.

    “I am not afraid of failure,” she said. “For better or for worse, I am “gözü kara” [fearless].‘

    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 2:04 pm on August 1, 2019 Permalink | Reply
    Tags: , Many Worlds,   

    From Many Worlds: “Exoplanets Discoveries Flood in From TESS” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    August 1, 2019
    Marc Kaufman

    1
    NASA’s Transiting Exoplanet Survey Satellite (TESS) has hundreds of “objects of interest” waiting to be confirmed as planets in the data from the space telescope’s four cameras. These three were the first confirmed TESS discoveries, identified last year during its first three months of observing. By the time the mission is done, TESS’s wide-field cameras will have covered the whole sky in search of transiting exoplanets around 200,000 of the nearest (and brightest) stars. (NASA / MIT / TESS)

    NASA/MIT TESS replaced Kepler in search for exoplanets

    The newest space telescope in the sky–NASA’s Transiting Exoplanet Survey Satellite, TESS — has been searching for exoplanets for less than a year, but already it has quite a collection to its name.

    The TESS mission is to find relatively nearby planets orbiting bright and stable suns, and so expectations were high from the onset about the discovery of important new planets and solar systems. At a meeting this week at the Massachusetts Institute of Technology devoted to TESS results, principal investigator George Ricker pronounced the early verdict.

    The space telescope, he said, “has far exceeded our most optimistic hopes.” The count is up to 21 new planets and 850 additional candidate worlds waiting to be confirmed.

    Equally or perhaps more important is that the planets and solar systems being discovered promise important results. They have not yet included any Earth-sized rocky planet in a sun’s habitable zone — what is generally considered the most likely, though hardly the only, kind of planet to harbor life — but they did include planets that offer a great deal when it comes to atmospheres and how they can be investigated.

    2
    This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. Insets show information about the planets, including their relative sizes, and how they compare to Earth. Temperatures given for TOI 270’s planets are equilibrium temperatures, (NASA’s Goddard Space Flight Center/Scott Wiessinger)

    One of the newest three-planet system is called TOI-270, and it’s about 75 light years from Earth. The star at the center of the system is a red dwarf, a bit less than half the size of the sun.

    Despite its small size, it’s brighter than most of the nearby stars we know host planets. And it’s stable, making its solar system especially valuable. When variations in the star’s light are minimal, and they’re less likely to get in the way of trying to pick up subtle changes caused by its orbiting planets.

    While none of the three planets are likely habitable, more planets may yet be found farther out in the star system, orbiting in more habitable orbits. A paper describing the system was published in the journal Nature Astronomy.

    “This system is exactly what TESS was designed to find — small, temperate planets that pass, or transit, in front of an inactive host star, one lacking excessive stellar activity, such as flares,” said lead researcher Maximilian Günther, a Torres Postdoctoral Fellow at the (MIT) Kavli Institute for Astrophysics and Space Research in Cambridge.

    “This star is quiet and very close to us, and therefore much brighter than the host stars of comparable systems. With extended follow-up observations, we’ll soon be able to determine the make-up of these worlds, establish if atmospheres are present and what gases they contain, and more.”

    This is essential both in terms of understand the particular planet, and in developing methods for reading the atmospheres of exoplanets more generally. Those readings will hopefully some day tell researchers that they have found a planet with an atmosphere out of chemical balance in ways that could only be the result of biology.

    The authors estimate that the James Webb Space Telescope, now scheduled to launch in 2021, will eventually have a view of the system for over half the year, and it should be able to pick out the atmospheric signals for both planets.

    NASA/ESA/CSA Webb Telescope annotated

    As explained in a NASA release, the innermost planet, TOI 270 b, is likely a rocky world about 25% larger than Earth. It orbits the star every 3.4 days at a distance about 13 times closer than Mercury orbits the sun. Based on statistical studies of known exoplanets of similar size, the science team estimates TOI 270 b has a mass around 1.9 times greater than Earth’s.

    Due to its proximity to the star, planet b is an scalding-hot world. Its equilibrium temperature — that is, the temperature based only on energy it receives from the star, which ignores additional warming effects from a possible atmosphere — is around 490 degrees Fahrenheit (254 degrees Celsius).

    The other two planets, TOI 270 c and d, are, respectively, 2.4 and 2.1 times larger than Earth and orbit the star every 5.7 and 11.4 days. Although only about half its size, both may be similar to Neptune in our solar system, with compositions dominated by gases rather than rock. They likely weigh around 7 and 5 times Earth’s mass, respectively.

    All of the planets are expected to be tidally locked to the star, which means they only rotate once every orbit and keep the same side facing the star at all times, just as the Moon does in its orbit around Earth.

    Planet c and d might best be described as mini-Neptunes, a type of planet not seen in our own solar system. The researchers hope further exploration of TOI 270 may help explain how two of these mini-Neptunes formed alongside a nearly Earth-size world.

    “An interesting aspect of this system is that its planets straddle a well-established gap in known planetary sizes,” said co-author Fran Pozuelos, a postdoctoral researcher at the University of Liège in Belgium.

    “It is uncommon for planets to have sizes between 1.5 and two times that of Earth for reasons likely related to the way planets form, but this is still a highly controversial topic. TOI 270 is an excellent laboratory for studying the margins of this gap and will help us better understand how planetary systems form and evolve.”

    4
    Only 31 light-years away from Earth, the exoplanet GJ 357 d catches light from its host star GJ 357, in this artistic rendering.

    And then there’s the planetary system of GJ 357.

    The newly discovered planets orbit an M-type dwarf about one-third the sun’s mass and size and about 40% cooler that our star. The system is located 31 light-years away, which makes it a relatively close neighbor.

    In February, TESS cameras caught the star dimming slightly every 3.9 days, revealing the presence of a transiting exoplanet that passes across the face of its star during every orbit and briefly dims the star’s light. That discovery led to the finding of two more planets [Astronomy and Astrophysics] around the star, including one that may be quite promising.

    “In a way, these planets were hiding in measurements made at numerous observatories over many years,” said Rafael Luque, a doctoral student at the Institute of Astrophysics of the Canary Islands (IAC) on Tenerife, who led the discovery team.

    6
    IAC

    “It took TESS to point us to an interesting star where we could uncover them.”

    But while researchers were looking at ground-based data to confirm the existence of the hot Earth, they uncovered two additional worlds. The farthest-known planet, named GJ 357 d, is the one that really caught their attention.

    “GJ 357 d is located within the outer edge of its star’s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the sun,” said co-author Diana Kossakowski at the Max Planck Institute for Astronomy in Heidelberg, Germany.


    Max Planck Institute for Astronomy campus, Heidelberg, Baden-Württemberg, Germany

    “If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface.”

    This GJ 357 system illustrates well how exoplanet discoveries are gathered, confirmed and then interpreted.

    8
    Transit data are rich with information. By measuring the depth of the dip in brightness and knowing the size of the star, scientists can determine the size or radius of the planet. The orbital period of the planet can be determined by measuring the elapsed time between transits. Once the orbital period is known, Kepler’s Third Law of Planetary Motion can be applied to determine the average distance of the planet from its stars. (NASA Ames)

    A planet orbiting GJ 357 was first identified via the transit method by TESS. Then it was confirmed using the ground-based radial velocity data collected from numerous ground-based telescopes over the years. That data was recoded and re-interpeted (with the assistance of the Carnegie Institution’s Paul Butler (who was part of the team that confirmed the detection of the first exoplanet in 1995) and the additional two planets were identified.

    9
    This artist’s illustration demonstrates the “wobble,” or radial velocity, technique for finding planets. The planet-detection technique relies on the fact that stars wobble back and forth as their planets circle around, tugging on them with their gravity. As a star moves toward us, the color of its light shifts to shorter, or bluer, wavelengths. As the star heads away, its light stretches into longer, or redder, wavelengths. The same principle, called the Doppler effect, causes sound from a speeding train to lower in pitch as it passes by.
    By measuring changes in the wavelength of light from a star, astronomers can track changes in the star’s velocity that arise from circling planets. By measuring the speed of the star and the period of the wobble, they can determine the mass and distance of the unseen planet, respectively. (NASA)

    Then the information was put through models by an interdisciplinary team and this announcement was the result:

    “An international team of astronomers… has characterized the first potentially habitable world outside of our own solar system.” The paper appeared in the journal Astrophysical Journal Letters.

    “This is exciting, as this is humanity’s first nearby super-Earth that could harbor life – uncovered with help from TESS, our small, mighty mission with a huge reach,” said Lisa Kaltenegger, associate professor of astronomy, director of Cornell’s Carl Sagan Institute and a member of the TESS science team.

    The exoplanet is more massive than our planet, and Kaltenegger said the discovery will provide insight into Earth’s heavyweight planetary cousins. “With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth, and we could pick out signs of life with telescopes that will soon be online,” she said.

    How did Kaltenegger and her colleagues get to that conclusion?

    The planet receives little more than a third of the radiation that Earth receives, making it similar to Mars. If the planet released gases present since its formation at a rate similar to Earth, the surface temperature would remain below freezing.

    But as their paper concludes:

    “Geological active worlds, like our Earth, are expected to build up CO2 concentrations due to the feedback of the carbonate-silicate cycle. We model atmospheres (with and without oxygen) as three examples, where we increase CO2 concentration so that the planet’s average surface temperature is above freezing.”

    “The sample reflection, emission and transmission spectra show features of a wide range of chemicals — water, carbon dioxide, methane, ozone and oxygen for Earth-like atmospheres from the Visible to Infrared wavelength — which would indicate habitability for observations with upcoming telescopes.”

    This is how the exoplanet drama works. Each significant discovery makes possible a future discovery, then additional hypotheses are put forward that often need new and more powerful viewing telescopes to prove or disprove. There are many goals in this enterprise, but the big one is clearly the discovery of clear signs of life far beyond Earth.

    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 9:03 am on July 29, 2019 Permalink | Reply
    Tags: "If Bacteria Could Talk", , Many Worlds, Quorum sensing   

    From Many Worlds: “If Bacteria Could Talk” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    July 29, 2019
    Marc Kaufman

    1
    Hawaiian lava cave microbial mats appear to have the highest levels and diversity of genes related to quorum sensing so far. (Stuart Donachie, University of Hawai`i at Mānoa)

    Did you know that many bacteria — some of the oldest lifeforms on Earth — can talk? Really.

    And not only between the same kind of single-cell bacteria, but back and forth with members of other species, too.

    Okay, they don’t talk in words or with sounds at all. But they definitely communicate in a meaningful and essential way, especially in the microbial mats and biofilms (microbes attached to surfaces surrounded by mucus) that constitute their microbial “cities.”

    Their “words” are conveyed via chemical signaling molecules — a chemical language — going from one organism to another, and are a means to control when genes in the bacterial DNA are turned “on” or “off.” The messages can then be translated into behaviors to protect or enhance the larger (as in often much, much larger) group.

    Called “quorum sensing,” this microbial communication was first identified several decades ago. While the field remains more characterized by questions than definitive answers, is it clearly growing and has attracted attention in medicine, in microbiology and in more abstract computational and robotics work.

    Most recently, it has been put forward as chemically-induced behavior that can help scientists understand how bacteria living in extreme environments on Earth — and potential on Mars — survive and even prosper. And the key finding is that bacteria are most successful when they form communities of microbial mats and biofilms, often with different species of bacteria specializing in particular survival capabilities.

    Speaking at the recent Astrobiology Science Conference in Seattle, Rebecca Prescott, a National Science Foundation Postdoctoral Research Fellow in Biology said this community activity may make populations of bacteria much more hardy than otherwise might be predicted.

    2
    Quorum sensing requires a community. Isolated Bacteria (and Archaea) have nobody to communicate with and so genes that are activated by quorum sensing are not turned “on.”

    “To help us understand where microbial life may occur on Mars or other planets, past or present, we must understand how microbial communities evolve and function in extreme environments as a group, rather than single species,” said Prescott,

    “Quorum sensing gives us a peek into the interactive world of bacteria and how cooperation may be key to survival in harsh environments,” she said.

    4
    Rebecca Prescott is a National Science Foundation Postdoctoral Fellow in Biology (1711856) and is working with principal investigator Alan Decho of the University of South Carolina on a NASA Exobiology Program grant.

    And because “quorum sensing” has not been investigated in the world of astrobiology, “this study will be the first to illuminate how microbial interactions might influence survival on Mars and early Earth conditions.”

    This makes quorum sensing of interest to NASA, Prescott told me, because it potentially broadens the universe of environments where bacteria might survive.

    “Microbes don’t function as single species in nature, like we have them in most of our experiments.,” Prescott told me. “It’s therefore important for us to try and understand them as interactive communities – the socialites that they are.”

    Prescott’s research has taken her to extreme environments such as hypersalty ponds with strong ultraviolet light in the Bahamas, the hot springs of Iceland and the lava caves beneath the Hawaiian Islands, to name a few.

    In some of these locales, such as the Bahamas hypersaline mats, it is not unusual for lifeforms to desiccate — a profound drying that few organisms can survive. Yet certain microbes — when enclosed in their protective, slimy biofilms formed with the assistance of quorum sensing — are able go dry for years and then regain activity when water returns.

    Prescott’s colleague and supervisor in the research, University of South Carolina Environmental Health Sciences Professor and Associate Dean for Research Alan Decho, said of these sites: “These are incredibility harsh environments, where very little life other than bacteria can exist.”

    The bacterial samples are now going into a Mars simulator chamber in Scotland. That simulator, in the University of Edinburgh lab of astrobiologist Charles Cockell, will be where the examples of extremophile bacteria are tested for compatibility with an early and then a later Mars atmosphere and to determine how and if their chemical “talking” changes.

    The presence of quorum sensing might also lead some day to the discovery of biosignatures on Mars. This is because the bacteria signaling molecules — acyl homoserine lactones (AHLs) — are neutral lipids, and lipids are often preserved in the rock record.

    5
    Quorum sensing was first identified and proven in the blowfish squid, which lives in sand off the Hawaiian Islands. bioluminescence. (Mattias Ormestad)

    In this tale of “talking bacteria” and their biofilms, it seems only proper that the species most associated with the discovery of quorum sensing by bacteria is the unusual bobtail squid of Hawai`i. The squid develops a striking bioluminescence at night, and it turns out that bacteria in its body are a source of the light.

    The bacteria in the squid (Vibrio fischeri) start the night dark and only become bioluminescent as the density of bacteria grows. That density leads, thanks to the quorum sensing phenomenon, to a changed expression of genes and release of proteins that lead to the bioluminescence. Most of the bacteria are later expelled when daytime comes.

    The tiny squid bacteria and the squid have their own symbiotic relationship: the bacteria collect a sugar and amino acid solution produced by the squid and the bacteria-induced light hides the squid’s silhouette when viewed from below.

    6
    Prescott and her colleagues collected microbial mats at San Salvador Island of the Bahamas. where a lot of “bacterial talking” occurs. This is a Mars analog site due to high saline and high UV environment.

    For bacteria to use quorum sensing, they must possess three characteristics: the ability to secrete a signaling molecule, the ability to detect a change in concentration of signaling molecules, and an ability to regulate gene expression as a response to that change.

    This process is highly dependent on how the signaling molecules spread. Quorum sensing signaling molecules generally released by individual bacteria in tiny amounts that can slip away undetected if the cell density in the area is low. At high cell densities, the concentration of signaling molecules may exceed its threshold level and trigger changes in gene expressions.

    6
    Alan Decho, a professor of microbial ecology at South Carolina University is a principal investigator on the NASA quorum sensing grant and worked with Prescott. He specializes in the study of biofilms.

    As a result, a main focus of quorum sensing research is on microbial mats and biofilms, the kind of slime-covered collections found most visibly in ponds and other waterways but most everywhere else too — on shower curtains, n the International Space Station orbiting the Earth, the plaque on your teeth, your cellphone and in fact in a number of places throughout our bodies. (Prescott makes a point of saying most bacteria are harmless, and even are essential for life.)

    Producing the protective biofilm mucus to make microbial “cities” is done as part of the quorum sensing process — an activity that helps create an environment that is more stable, with different cells or species doing different tasks. A bit like ants, perhaps, but on a microscopic level.

    The biofilms are also organized in part through quorum sensing in ways that result in bacteria that are more resistant to radiation being on the surface of the film while those that are harmed by oxygen would be found deeper in the mat.

    “Biofilm genes are controlled by quorum sensing,” Prescott told me. “Basically there has to be a lot of you for a mucus layer to make a difference, so microbes start making mucus once they sense other neighbors around.“

    Radiation protection provides a good model for how members of a mixed species biofilm will have different roles to play.

    ”The species that are more tolerate of radiation—or individual cells of same species—will exist at surface, and sometimes produce chemicals that are UV protectants. That also provides protection for others below that are less tolerate to UV. In addition, the biofilm mucus (exopolysaccahride) is a UV protectant itself.”

    “So certain members may be producing more mucus, while others are breaking down nutrients. Many biofilm researchers say biofilms are more like multi-cellular organisms than single cell, and it is certainly a step towards multicellularity.”

    And these organized activities are often coordinated through some sort of quorum sensing; i.e, chemical “talking.”

    7
    Biofilms made up of a variety of species did better than most other biological samples when exposed to space conditions on the International Space Station. (ESA)

    Armed with a protective covering and other community-based strengths, biofilms are adaptable. Consider, for instance, the inside of the International Space Station, some 250 miles above the Earth. Biofilms can be found there all the time, and not because they were purposefully brought up.

    5
    A Mars simulation chamber in the Edinburgh lab of Charles Cockell is used for testing which microbes and biofilms might survive harsh Martian conditions. (Charles Cockell)

    One batch of mixed bacterial biofilms, however, was intentionally delivered to the ISS for a European Space Agency-led study of bacterial microbes and larger species including fungi and lichen. The samples were exposed to the pressures, temperatures, radiation and more of space over a two-year period.

    While not all of the biofilm material survived and prospered, much of it did — more than most other samples.

    Prescott’s astrobiology work in Cockell’s Edinburgh lab will expose her collected biofilms to different but also harsh conditions — simulated Mars environments that can be changed to explore the effects of different conditions including extreme temperature, pressure, dryness, and radiation.

    The simulator is part of a cutting-edge effort to test microbes for potential future uses on Mars including manufacturing, “bio-mining,” and transforming elements available on Mars into a form that plants can use. Prescott will use the chamber to look for changes in the biofilm’s gene expression and quorum sensing under Mars conditions and will look at the AHL signaling molecules to see which species can maintain them.

    “We have no idea what will happen in the Mars environments; maybe they’ll die and maybe they’ll live,” she said. “And who knows? There may be quorum sensing systems on Mars different from anything we know.”

    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 4:40 pm on June 24, 2019 Permalink | Reply
    Tags: "The Interiors of Exoplanets May Well Hold the Key to Their Habitability", , , “The heart of habitability is in planetary interiors” concluded Carnegie geochemist George Cody, , Cosmochemistry, , Deep Carbon Observatory’s Biology Meets Subduction project, Findings from the Curiosity rover that high levels of the gas methane had recently been detected on Mars., , Many Worlds, PREM-Preliminary Reference Earth Model, This idea that subsurface life on distant planets could be identified by their byproducts in the atmosphere has just taken on a new immediacy, We’ve only understood the Earth’s structure for the past hundred years.   

    From Many Worlds: “The Interiors of Exoplanets May Well Hold the Key to Their Habitability” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    June 23, 2019
    Marc Kaufman

    1
    Scientists have had a working — and evolving — understanding of the interior of the Earth for only a century or so. But determining whether a distant planet is truly habitable may require an understanding of its inner dynamics — which will for sure be a challenge to achieve. (Harvard-Smithsonian Center for Astrophysics)

    The quest to find habitable — and perhaps inhabited — planets and moons beyond Earth focuses largely on their location in a solar system and the nature of its host star, the eccentricity of its orbit, its size and rockiness, and the chemical composition of its atmosphere, assuming that it has one.

    Astronomy, astrophysics, cosmochemistry and many other disciplines have made significant progress in characterizing at least some of the billions of exoplanets out there, although measuring the chemical makeup of atmospheres remains a immature field.

    But what if these basic characteristics aren’t sufficient to answer necessary questions about whether a planet is habitable? What if more information — and even more difficult to collect information — is needed?

    That’s the position of many planetary scientists who argue that the dynamics of a planet’s interior are essential to understand its habitability.

    With our existing capabilities, observing an exoplanet’s atmospheric composition will clearly be the first way to search for signatures of life elsewhere. But four scientists at the Carnegie Institution of Science — Anat Shahar, Peter Driscoll, Alycia Weinberger, and George Cody — argued in a recent perspective article in Science that a true picture of planetary habitability must consider how a planet’s atmosphere is linked to and shaped by what’s happening in its interior.

    They argue that on Earth, for instance, plate tectonics are crucial for maintaining a surface climate where life can fill every niche. And without the cycling of material between the planet’s surface and interior, the convection that drives the Earth’s magnetic field would not be possible and without a magnetic field, we would be bombarded by cosmic radiation.

    1
    What makes a planet potentially habitable and what are signs that it is not. This graphic from the Carnegie paper illustrates the differences (Shahar et al.)

    “The perspective was our way to remind people that the only exoplanet observable right now is the atmosphere, but that the atmospheric composition is very much linked to planetary interiors and their evolution,” said lead author Shahar, who is trained in geological sciences. “If there is a hope to one day look for a biosignature, it is crucial we understand all the ways that interiors can influence the atmospheric composition so that the observations can then be better understood.”

    “We need a better understanding of how a planet’s composition and interior influence its habitability, starting with Earth,” she said. “This can be used to guide the search for exoplanets and star systems where life could thrive, signatures of which could be detected by telescopes.”

    It all starts with the formation process. Planets are born from the rotating ring of dust and gas that surrounds a young star.

    The elemental building blocks from which rocky planets form–silicon, magnesium, oxygen, carbon, iron, and hydrogen–are universal. But their abundances and the heating and cooling they experience in their youth will affect their interior chemistry and, in turn, defining factors such ocean volume and atmospheric composition.

    “One of the big questions we need to ask is whether the geologic and dynamic features that make our home planet habitable can be produced on planets with different compositions,” Carnegie planetary scientist Peter Driscoll explained in a release.

    In the next decade as a new generation of telescopes come online, scientists will begin to search in earnest for biosignatures in the atmospheres of rocky exoplanets. But the colleagues say that these observations must be put in the context of a larger understanding of how a planet’s total makeup and interior geochemistry determines the evolution of a stable and temperate surface where life could perhaps arise and thrive.

    “The heart of habitability is in planetary interiors,” concluded Carnegie geochemist George Cody.

    Our knowledge of the Earth’s interior starts with these basic contours: it has a thin outer crust, a thick mantle, and a core the size of Mars. A basic question that can be asked and to some extent answered now is whether this structure is universal for small rocky planets. Will these three layers be present in some form in many other rocky planets as well?

    Earlier preliminary research published in the The Astrophysical Journal suggests that the answer is yes – they will have interiors very similar to Earth.

    “We wanted to see how Earth-like these rocky planets are. It turns out they are very Earth-like,” said lead author Li Zeng of the Harvard-Smithsonian Center for Astrophysics (CfA)

    To reach this conclusion Zeng and his co-authors applied a computer model known as the Preliminary Reference Earth Model (PREM), which is the standard model for Earth’s interior. They adjusted it to accommodate different masses and compositions, and applied it to six known rocky exoplanets with well-measured masses and physical sizes.

    They found that the other planets, despite their differences from Earth, all should have a nickel/iron core containing about 30 percent of the planet’s mass. In comparison, about a third of the Earth’s mass is in its core. The remainder of each planet would be mantle and crust, just as with Earth.

    “We’ve only understood the Earth’s structure for the past hundred years. Now we can calculate the structures of planets orbiting other stars, even though we can’t visit them,” adds Zeng.

    The model assumes that distant exoplanets have chemical compositions similar to Earth. This is reasonable based on the relevant abundances of key chemical elements like iron, magnesium, silicon, and oxygen in nearby systems. However, planets forming in more or less metal-rich regions of the galaxy could show different interior structures.

    While thinking about exoplanetary interiors—and some day finding ways to investigate them — is intriguing and important, it’s also apparent that there’s a lot more to learn about role of the Earth’s interior in making the planet habitable.

    In 2017, for instance, an interdisciplinary group of early career scientists visited Costa Rica’s subduction zone, (where the ocean floor sinks beneath the continent) to find out if subterranean microbes can affect geological processes that move carbon from Earth’s surface into the deep interior.

    3
    Donato Giovannelli and Karen Lloyd collect samples from the crater lake in Poás Volcano in Costa Rica. (Katie Pratt)

    The study shows that microbes consume and trap a small but measurable amount of the carbon sinking into the trench off Costa Rica’s Pacific coast. The microbes may also be involved in chemical processes that pull out even more carbon, leaving cement-like veins of calcite in the crust.

    According to their new study in Nature, the answer is yes.

    In all, microbes and calcite precipitation combine to trap about 94 percent of the carbon squeezed out from the edge of the oceanic plate as it sinks into the mantle during subduction. This carbon remains naturally sequestered in the crust, where it cannot escape back to the surface through nearby volcanoes in the way that much carbon ultimately recycles.

    These unexpected findings have important implications for how much carbon moves from Earth’s surface into the interior, especially over geological timescales. The research is part of the Deep Carbon Observatory’s Biology Meets Subduction project.

    Overall, the study shows that biology has the power to affect carbon recycling and thereby deep Earth geology.

    “We already knew that microbes altered geological processes when they first began producing oxygen from photosynthesis,” said Donato Giovannelli of University of Naples, Italy (and who I knew from time spent at the Earth-Life Science Institute Tokyo.) He is a specialist in extreme environments and researches what they can tell us about early Earth and possibly other planets.

    “I think there are probably even more ways that biology has had an outsized impact on geology, we just haven’t discovered them yet.”

    The findings also shows, Giovanelli told me, that subsurface microbes might have a similarly outsized effect on the composition and balancing of atmospheres—“hinting to the possibility of detecting the indirect effect of subsurface life through atmosphere measurements of exoplanets,” he said.

    5
    The 2003 finding by Michael Mumma and Geronimo Villanueva of NASA Goddard Space Flight Center showing signs of major plumes of methane on Mars. While some limited and seasonably determined concentrations of methane have been detected since, there has been nothing to compare with the earlier high methane readings Mars — until just last week. (NASA/ M. Mumma et al)

    This idea that subsurface life on distant planets could be identified by their byproducts in the atmosphere has just taken on a new immediacy with findings from the Curiosity rover that high levels of the gas methane had recently been detected on Mars. Earlier research had suggested that Mars had some subsurface methane, but the amount appeared to be quite minimal — except as detected once back in 2003 by NASA scientists.

    None of the researchers now or in the past have claimed that they know the origin of the methane — whether it is produced biologically or through other planetary processes. But on Earth, some 90 percent of methane comes from biology — bacteria, plants, animals.

    Could, then, these methane plumes be a sign that life exists (or existed) below the surface of Mars? It’s possible, and highlights the great importance of what goes on below the surface of planets and 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 12:50 pm on May 28, 2019 Permalink | Reply
    Tags: "The Message of Really, “Kimberley” formation of Gale Crater on Mars taken by NASA’s Curiosity rover, Ethiopia’s Danakil Depression, , Many Worlds, Really Extreme Life"   

    From Many Worlds: “The Message of Really, Really Extreme Life” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    May 28, 2019
    Marc Kaufman

    1
    Hydrothermal system at Ethiopia’s Danakil Depression, where uniquely extreme life has been found in salt chimneys and surrounding water. The yellow deposits are a variety of sulphates and the red areas are deposits of iron oxides. Copper salts color the water green. (Felipe Gomez/Europlanet 2020 RI)

    Ethiopia’s Dallol volcano and hot springs have created an environment about as hostile to life as can be imagined.

    Temperatures in the supersaturated water reach more than 200 degrees F (94 C) and are reported to approach pure acidity, with an extraordinarily low pH of 0.25. The environment is also highly salty, with salt chimneys common.

    Yet researchers have just reported finding ultra-small bacteria living in one of the acidic, super-hot salt chimneys. The bacteria are tiny — up to 20 times smaller than the average bacteria — but they are alive and in their own way thriving.

    In the world of extremophiles, these nanohaloarchaeles order bacteria are certainly on the very edge of comprehension. But much the same can be said of organisms that can withstand massive doses of radiation, that survive deep below the Earth’s surface with no hint of life support from the sun and its creations, that keep alive deep in glacier ice and even floating high in the atmosphere. And as we know, spacecraft have to be well sterilized because bacteria (in hibernation) aboard can survive the trip to the moon or Mars.

    Not life it is generally understood. But the myriad extremophiles found around the globe in recent decades have brought home the reality that we really don’t know where and how life can survive; indeed, these extremophiles often need their conditions to be super-severe to succeed.

    And that’s what makes them so important for the search for life beyond Earth. They are proof of concept that some life may well need planetary and atmospheric conditions that would have been considered utterly uninhabitable not long ago.

    2
    Montage from the Dallol site: (A) the sampling site, (B) the small chimneys (temperature of water 90 ºC. (C) D9 sample from a small chimney in (A). (D-L) Scanning Electron Microscope and (M-O) Scanning Transmission Electron Microscope images of sample D9 showing the morphologies of ultra-small microorganisms entombed in the mineral layers. (Gomez et al/Europlanet 2020 Research Infrastructure)

    The unusual and extreme life and geochemistry of Dallol has been studied by a team led by Felipe Gómez from Astrobiology Center in Spain.

    The samples were collected during a field trip to the Dallol volcano and the Danakil Depression in northern Ethiopia in January 2017, which was funded by the Europlanet 2020 Research Infrastructure (RI). The results were published this week in the journal, Scientific Reports.

    The area is consistently one of the hottest in the world, both because of its near-equatorial location, the Dallol volcano and hot springs, and that much of it is below sea level.

    Its psychedelic appearance comes from the condensation of superheated water saturated with various salts, including silver chloride, zinc iron sulphide, manganese dioxide and normal rock-salt.

    The team collected samples of the thin layers of salt deposits from the wall of a yellow chimney stack and a bluish pool of water surrounding the outcrop (above.)

    The samples were brought in sterile, sealed vials to state-of-the-art facilities in Spain, where they were analyzed using a range of techniques, including electron microscopy, chemical analysis and DNA sequencing.

    The team identified tiny, spherical structures within the salt samples that had a high carbon content, demonstrating an unambiguously biological origin.

    “This is an exotic, multi-extreme environment, with organisms that need to love high temperature, high salt content and very low pH in order to survive,” Gómez said. And love it they do, raising the most interesting question of whether they adapted to the conditions or emerged from them.

    Just last month, the same international team published a review in the journal Astrobiology describing the close parallels between the Dallol area and the hydrothermal environments found on Mars — including the Gusev Crater, where NASA’s Spirit Mars Exploration Rover landed in .

    As is the norm in the effort to understand life in extreme conditions and astrobiology generally, they focused on the geology and geochemistry of the site that gave rise to the extreme life.

    “The physical and compositional features of the Dallol deposits, their mineralogies, sedimentary and alteration features, and their location in a region of basaltic volcanism of planetary-scale importance, are testament to the novelty of this extreme environment and its ability to host life-forms and to preserve biosignatures,” they wrote.

    “It is therefore also a reliable analog to ancient martian environments and habitats. Deep investigation of the characteristics of this unique geological site will improve our understanding of the limits of life on Earth and inform the search for life on Mars.”

    3
    A view from the “Kimberley” formation of Gale Crater on Mars taken by NASA’s Curiosity rover. The mission has confirmed the long-ago presence of large amounts of water on the planet, as well as organic compounds needed for life. Curiosity was not equipped to be a life detection mission, but the follow-up Mars 2020 rover mission will be. The colors are adjusted so that rocks look approximately as they would if they were on Earth, to help geologists interpret the rocks. day, or sol, of the mission. (NASA/JPL-Caltech/MSSS)

    While this summation is surely accurate, it is also true that findings like these tell a larger story that goes well beyond Mars. Because the discovery of such a vast number and variety of extremophiles on Earth is one of the key factors that has led many space scientists and astrobiologists to conclude that life beyond Earth is likely.

    If life can survive such unusual and extreme conditions on Earth, logic says that this flexibility would no doubt be present on other potentially habitable planets and moons.

    Other major factors pointing to the plausibility of life beyond Earth are now broadly accepted:

    We now know there are billions upon billions of stars in our own Milky Way galaxy, and that most of them have planets orbiting them. The Kepler Space Telescope was crucial to reaching that consensus through its survey of one small bit of the distant sky.
    The most common planets are small and rocky ones, and some of them are within the habitable zones of their host star. This means the planet can at least sometimes support liquid water; in other words that it is neither too hot (close to its star) or too cold (far from its star.) Liquid water is considered to be essential to assemble and support life.
    The physics and chemistry of the cosmos appear to be consistent with what exists on Earth.

    None of this means any particular planet will support life since there are many other factors at play, such as how circular or elliptical the planet’s orbit might be, as well as the presence and composition of an atmosphere and a protective magnetic field. But our increasingly better understanding of exoplanets, solar systems and extreme life has brought legions of scientists into that hunt for extraterrestrial life — and they have found many ways to move forward as well as to avoid errors.

    3
    An overview of the past, present, and future of research on remotely detectable biosignatures from an Astrobiology journal paper by NASA NExSS participants. Research historically has focused on cataloguing lists of substances or physical features that yield spectral signatures as indicators of potential life on exoplanets. Recent progress has led to an understanding of how environmental context is critical to interpret signatures of nonliving planets that may mimic some effects of biota. Exoplanet observing telescopes in the near future hold promise to provide direct spectral imaging that can chemically characterize rocky planets in the habitable zone of their parent star. Anticipating these capabilities, the field should seek to develop frameworks to utilize widespread but sparse data to deliver quantitative assessments of whether or not a given planet has life. (Aaron Gronstal)

    While the Dallol discoveries (and others like them) are encouraging, they are sobering as well. Finding these creatures here on Earth has been very difficult, so imagine how challenging it will be to detect the presence of comparable microbial life on now desiccated Mars or a distant planet.

    Indeed, it would be impossible because their small numbers and limited metabolism don’t provide enough of a chemical biosignature to be detected even by telescopes and spectrographs a million times more powerful than what we have now. In terms of exoplanets, what is needed is a planet where plentiful life is providing a strong global biosignature of some kind.

    That ups the ante quite a bit in the search for life beyond Earth. But there are a vast multitude of planets out there, and a logic to the possibility that some have enough life on them for us to some day detect it.

    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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