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  • richardmitnick 2:40 pm on June 7, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds   

    From Many Worlds: “Breakthrough Findings on Mars Organics and Mars Methane” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-06-07
    Marc Kaufman

    NASA Mars Curiosity Rover

    After almost six years of searching, drilling and analyzing on Mars, the Curiosity rover team has conclusively detected three types of naturally-occurring organics that had not been identified before on the planet.

    The Mars organics Science paper by NASA’s Jennifer Eigenbrode and much of the rover’s Sample Analysis on Mars (SAM) instrument team was twinned with another paper describing the discovery of a seasonal pattern to the release of the simple organic gas methane on Mars.

    This finding is also a major step forward not only because it provides ground truth for the difficult question of whether significant amounts of methane are in the Martian atmosphere, but equally important it determines that methane concentrations appear to change with the seasons. The implications of that seasonality are intriguing, to say the least.

    In an accompanying opinion piece in Science, Inges Loes ten Kate of Utrecht University in Netherlands wrote of the two papers: “Both these findings are breakthroughs in astrobiology.”

    2
    Remains of 3.5 billion-year old lake that once filled Gale Crater. NASA scientists concluded early in the Curiosity mission that the planet was habitable long ago based on the study of mudstone remains like these. (NASA/JPL-Caltech/MSSS).

    Finding organic compounds on Mars has been a prime goal of the Curiosity rover mission.

    Those carbon-based compounds surely fall from the sky on Mars, as they do on Earth and everywhere else, but identifying them has proven illusive.

    The consequences of that non-discovery have been significant. Going back to the Viking missions of 1976, scientists concluded that life was not possible on Mars because there were no organics, or none that were detected.

    But the reasons for the disappearing organics are pretty well understood. Without much of an atmosphere to protect it, the Martian surface is bombarded with ultraviolet radiation, which can destroy organic compounds. Or, in the case of the samples discovered by the SAM team, large organic macromolecules — the likes of proteins, membranes and DNA — are broken up into much smaller pieces.

    That’s what the team found, Eigenbrode told me. The organics were probably preserved, she said, because of exceptionally high levels of sulfur present in that part of Gale Crater.

    The organics, extracted from mudstone at the Mojave and Confidence Hill sites, had bonded tightly with ancient non-organic material. The organic material was freed to be collected as gas only after being exposed to temperatures of more than 500 to 800 centigrade in the SAM oven.

    “This material was buried for billions of years and then exposed to extreme surface conditions, so there’s a limit to what we can learn about. Did it come from life? We don’t know.

    “But the fact we found the organic carbon adds to the habitability equation. It was in a lake environment that we know could have supported life. Organics are things that organisms can eat.”

    It will take different kinds of instruments and samples from drilling deeper into the extreme Martian surface to answer the question of whether the organics came from living microbes. But for Eigenbrode, future answers of either “yes” or “no” are almost equally interesting.

    Finding clear signs of early Martian life would certainly be hugely important, she said. But a conclusion that Mars never had life — although it had conditions some 3.5 to 3.8 billion years ago quite similar to conditions on Earth at that time — raises the obvious question of “why not?”

    3
    NASA’s Curiosity rover raised robotic arm with drill pointed skyward while exploring Vera Rubin Ridge at the base of Mount Sharp inside Gale Crater. This navcam camera mosaic was stitched from raw images taken on Sol 1833, Oct. 2, 2017 and colorized. (NASA/JPL-Caltech/Ken Kremer, Marco Di Lorenzo)

    Organic molecules are the building blocks of all known life on Earth, and consist of a wide variety of molecules made primarily of carbon, hydrogen, and oxygen atoms. However, organic molecules can also be made by chemical reactions that don’t involve life.

    Examples of non-biological sources include chemical reactions in water at ancient Martian hot springs or delivery of organic material to Mars by interplanetary dust or fragments of asteroids and comets.

    It needs to be said that today’s Mars organics announcement was not the first we have heard. In 2014, a NASA team reported the presence of chlorine-based organics in Sheepbed mudstone at Yellowknife Bay, the first ancient Mars lake visited by Curiosity.

    That work, led by NASA Goddard scientists Caroline Freissinet and Daniel Glavin and published in the Journal of Geophysical Research, focused on signatures from unusual organics not seen naturally on Earth.

    The organics were complex and made entirely of Martian components, the paper reported. But because they combined chlorine with the organic hydrocarbons, they are not considered to be as “natural” as the discovery announced today.

    And when it comes to organics on Mars, the complicated history of research into the presence of the gas methane (a simple molecule that consists of carbon and hydrogen) also shows the great challenges involved in making these measurements on Mars.

    4
    By measuring absorption of light at specific wavelengths, the tunable laser spectrometer on Curiosity measures concentrations of methane, carbon dioxide and water vapor in the Martian atmosphere. (NASA)

    4
    The gold-plated Sample Analysis on Mars contains three instruments that make the measurements of organics and methane. (NASA/Goddard Space Flight Center)

    The second Science paper, authored by Chris Webster of NASA’s Jet Propulsion Lab and colleagues, reports that the gas methane has been detected regularly in recent years, with surprising seasonality.

    “The history of Mars methane has been frustrating, with reports of some large plumes and spikes detected, but none have been repeatable. It’s almost like they’re random,” he told me. “But now we can see a large seasonal cycle in the background of these detections, and that’s extremely important.”

    Over three Mars years, or almost five Earth years, Webster said there have been significant increases in methane detected during the summer, and especially the late summer. That tripling of the methane counts is considered too great to be random, especially since the count declines as predicted after the summer ends.

    No definite explanation of why this happens has emerged yet, but one theory has been embraced by some scientists.

    While it is still cold in the Martian summer, it can get warm enough where the sun shines directly on a collection of ice for some melting to occur. And that melting, the paper reports, could provide an escape valve for methane collected long ago under the surface. The process is termed “microseepage.”

    5
    This illustration shows the ways in which methane from the subsurface might find its way to the
    surface where its release could produce the large seasonal variation in the atmosphere
    as observed by Curiosity. Potential methane sources include byproducts from organisms alive or long dead, ultraviolet degradation of organics, or water-rock chemistry; and its losses include atmospheric photochemistry and surface reactions. Seasons refer to the northern hemisphere. The plotted data is from Curiosity’s TLS-SAM instrument, and the curved line through the data is to aid the eye. (NASA/JPL-Caltech)

    Methane is a crucial organic in astrobiology because most of that gas found on Earth comes from biology, although various non-biological processes can produce methane as well.

    Today’s paper by Webster et al is the third in Science on Mars methane as measured by Curiosity, and it is the first to find a seasonal pattern. The first paper, in 2013 Science, actually reported there was no methane measured in early runs, a conclusion that led to push-back from many of those working in the field.

    While the Mars methane results released today are being described as a “breakthrough,” they follow closely the findings of a Science paper in 2009 by Michael Mumma and Geronimo Villanueva, both at NASA Goddard.

    The two reported then similar findings of plumes of methane on Mars, of a seasonality associated with their distribution, and a similar conclusion that the methane probably was coming from subsurface reservoirs. Like Webster et al, Mumma and Villanueva said they were unable to determine if the source of methane was biological or geological.

    The methane levels in the plumes they found were considerably higher than detected so far by Curiosity, but what they were detecting was quite different. Using ground-based telescopes, they detected the high concentrations in two specific areas over a number of years, while Curiosity is measuring methane levels that are more global or regional.

    Just as Webster was criticized for his initial paper saying there was no methane detected on Mars, the Mumma team also got sharp questions about their methodology and conclusions. This grew as their numerous follow-up efforts to detect the Mars methane proved unsuccessful.

    But now Webster says the Curiosity findings have essentially “confirmed” what Mumma and Villanueva reported nine years ago.

    Still, the Curiosity results are a breakthrough because they were made on Mars rather than through a telescope. Mumma, who described the new Curiosity results as “satisfying,” agreed that they were a major step forward.

    “This is how science works,” he said. “We do our work and put out our papers and other scientists react. We take it all in and make changes if needed. But the big changes come when new, and maybe different, data is presented.”

    And that’s exactly what will be happening soon regarding methane on Mars. Beginning early this year, the European/Russian Trace Gas Orbiter (TGO) has been collecting data specifically on Mars gases including methane. Unlike previous Mars methane campaigns, this one can potentially determine whether the methane being released from below the surface was formed by biology or geology — although not without great difficulty.

    Mumma, who is part of that TGO team, said the first release of information is due in the fall.

    See the full article here .


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    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

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    • stewarthoughblog 12:28 am on June 8, 2018 Permalink | Reply

      Fascinating results and science from exploration and experiments on Mars. Understanding that much of the funding justification is predicated on the possibility of hopefully finding evidence of life, past or present, the whole thing is seriously over-optimistic and not scientifically based on reality. Proposing Mars was once habitable to a level similar on Earth is extremely speculative, especially considering that primordial Earth conditions are not comprehensively understood. More importantly, there are no naturalistic processes capable of creating life, no matter the planet examined. Consequently, the only life found on Mars will be Earth effluent.

      Like

  • richardmitnick 11:45 am on May 30, 2018 Permalink | Reply
    Tags: , Existence of a thick haze around the early Archean Earth and probably today around some and perhaps many exoplanets, Exoplanet biosignatures, Many Worlds, NASA Goddard Space Flight Center astronomer and astrobiologist Giada Arney, Niki Parenteau of NASA’s Ames Research Center, Radiation-under what conditions the organisms can survive, So how did organisms survive the radiation assault?, The microbes-and-haze experiment is one of many that Parenteau is working on in the general field of biosignatures, The search for extraterrestrial life, This can all tested in a lab   

    From Many Worlds: “Joining the Microscope and the Telescope in the Search for Life Beyond Earth” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    2018-05-30
    Marc Kaufman

    1
    Niki Parenteau of NASA’s Ames Research Center is a microbiologist working in the field of exoplanet and Mars biosignatures. She adds a laboratory biology approach to a field generally known for its astronomers, astrophysicists and planetary scientists. (Marisa Mayer, Stanford University.)

    The world of biology is filled with labs where living creatures are cultured and studied, where the dynamics of life are explored and analyzed to learn about behavior, reproduction, structure, growth and so much more.

    In the field of astrobiology, however, you don’t see much lab biology — especially when it comes to the search for life beyond Earth. The field is now largely focused on understanding the conditions under which life could exist elsewhere, modeling what chemicals would be present in the atmosphere of an exoplanet with life, or how life might begin as an organized organism from a theoretical perspective.

    Yes, astrobiology includes and learns from the study of extreme forms of life on Earth, from evolutionary biology, from the research into the origins of life.

    But the actual bread and butter of biologists — working with lifeforms in a lab or in the environment — plays a back seat to modeling and simulations that rely on computers rather than actual life.

    There are certainly exceptions, and one of the most interesting is the work of Mary “Niki” Parenteau at NASA’s Ames Research Center in the San Francisco Bay area.

    2
    Niki Parenteau with her custom-designed LED array, can reproduce the spectral features of different simulated stellar and atmospheric conditions to test on primitive microbes. (Marc Kaufman)

    A microbiologist by training, she has been active for over five years now in the field of exoplanet biosignatures — trying to determine what astronomers could and should look for in the search for extraterrestrial life.

    Working in her lab with actual live bacteria in laboratory flasks, test tubes and tanks, she is conducting traditional biological experiments that have everything to do with astrobiology.

    She takes primitive bacteria known to have existed in some form on the early Earth, and she blasts them with the radiation that would have hit the planet at the time to see under what conditions the organisms can survive. She has designed ingenious experiments using different forms of ultraviolet light and a LED array that simulate the broad range of radiations that would come from different types of stars as well.

    What makes this all so intriguing is that her work uses, and then moves forward, cutting edge modeling from astronomers and astrobiologists regarding thick photochemical hazes understood to have engulfed the early Earth — making the planet significantly colder but also possibly providing some protection from deadly ultraviolet radiation.

    That was a time when the atmosphere held very little oxygen, and when many organisms had to make their living via carbon dioxide and sulfur-based photosynthesis that did not use water and did not produce oxygen. This kind of photosynthesis has been the norm for much of the history of life on Earth, and certainly could be common on many exoplanets orbiting other stars as well.

    So anything learned about how these early organisms survived in frigid conditions with high ultraviolet radiation — and what potentially detectable byproducts they would have produced under those conditions — would be important in the search for biosignatures and extraterrestrial life.

    Parenteau has spent years learning from astronomers working to find ways to characterize exoplanet biosignatures, and she has been eager to convert her own work into something useful to them.

    “These are not questions that can be answered by one discipline,” she told me. “I certainly understand that when it comes to exoplanet biosignatures and life detection, astronomy has to be in the lead. But biologists have a role to play, especially when it comes to characterizing what life produces.”

    Here is the back story to Parenteau’s work:

    Recent work by NASA Goddard Space Flight Center astronomer and astrobiologist Giada Arney and colleagues points to the existence of a thick haze around the early Archean Earth and probably today around some, and perhaps many, exoplanets.

    3
    Giada Arney is an astronomer and astrobiologist at NASA’s Goddard Space Flight Center. As with Parenteau, her general approach to science was formed at the University of Washington’s pioneering Virtual Planetary Laboratory. (NASA/Goddard Space Flight Center)

    This haze — which is more like pollution than clouds — is produced by the interaction of strong incoming radiation and chemicals (most commonly methane and carbon dioxide) already in the atmosphere.

    The haze, Arney concluded based on elaborate modeling of those radiation-chemical interactions, would be hard on any life that might exist on the planet because it would reduce surface temperatures significantly, though probably not always fatally.

    On the other hand, the haze would also have the effect of blocking 84 percent of the destructive ultraviolet radiation bombarding the planet — especially the most damaging ultraviolet-C light that would otherwise destroy nucleic acids in cells and disrupt the working of DNA. (Ultraviolet-C radiation is used as a microbial disinfectant.)

    Ozone in our atmosphere now plays the role of blocking the most destructive forms of UV radiation, but ozone is formed from oxygen and on early Earth there was very little oxygen at all.

    So how did organisms survive the radiation assault? Might it have been that haze? And might there be hazes surrounding exoplanets as well? (None have been found so far.)

    It’s difficult enough to sort through the potentially protective role of a haze on early Earth. To do it for exoplanets requires not only an understanding of the effects of a haze on ultraviolet light, but also how the dynamics of a haze would change based on the amounts and forms of radiation emitted by different types of stars.

    It’s all very complicated, but the answers needn’t be theoretical, Arney concluded. They could be tested in a lab.

    And that’s where Parenteau comes in, with her desire and ability to design biological experiments that might help scientists understand better how to look for life on distant exoplanets.

    “I knew that (Parenteau) had been super interested in this kind of question for a long time,” Arney said. “She one of the few people in the world with the know-how to simulate an atmosphere, and probably the only one in the world who could do the experiment.”

    4
    The 48 LEDs (light-emitting diodes) of the board designed and created by Parenteau and Ames intern Cameron Hearne. Each one is independently controlled and can be used to simulate the amount of radiation arriving on a planetary surface — taking into account the flux from the planet’s star and some aspects of its atmosphere. A microbe is then exposed to the radiation to see whether or how it can survive. (Niki Parenteau.)

    Parenteau’s experiment at first looks pretty low-tech, but in fact it’s very much custom-designed and custom-built.

    The ultraviolet bulbs include the powerful, germicidal ultraviolet-C variety, some of the glass for the experiment is made of special quartz that is transparent to that ultraviolet light, the LED array has 48 tiny bulbs that can be controlled by software to provide different amounts and kinds of light as identified and provided by Arney

    Before designing and making her own LED board with Ames intern Cameron Hearne, Parenteau met with solar panel specialists who might be able to provide an instrument she could use, but it turned out they were very expensive and not nearly as versatile as she wanted. Having grown up on a farm in northern Idaho, Parenteau is comfortable with making things from scratch, and her experiments reflect that comfort and talent.

    How would Parenteau determine whether the haze does indeed protect the microbial cells after exposing them to the various radiation regimes? This is how she explained the process, which measures the number of cells living or dead given a simulated UV and stellar bombardment:

    “Imagine the cells as soap bubbles in a clear glass. If you look through the glass, the soap bubbles prevent you from seeing through and the glass has a higher ‘optical density.’ However, if you pop or lyse the soap bubbles, suddenly you can see through the glass and the optical density decreases.

    “The latter represents dead ‘popped’ cells that were killed by the UV irradiation. I predict that by simulating the spectral qualities of the haze, which decreases the UV flux by 84%, more cells will survive.”

    The Parenteau-Arney collaboration is being funded through a National Astrobiology Institute grant to the University of Washington’s famously-interdisciplinary Virtual Planetary Laboratory.

    The microbes-and-haze experiment is one of many that Parenteau is working on in the general field of biosignatures. While the haze experiment is primarily designed to determine if microbes could survive a UV bombardment if a haze was present, she is also working on the central question of what might constitute a biosignature.

    With that in mind, she is also measuring the gases produced by microbes under different radiation and atmospheric conditions, and that is directly applicable to searching for extraterrestrial life.

    5
    A densely-packed community of microbes, including oxygen-producing cyanobacteria as well as anoxygenic purple and green bacteria, being studied with Parenteau’s LED array. A central question involves what gases are emitted and might be detectable on a distant planet. (Niki Parenteau)

    6
    Parenteau’s lab glove box with green, purple and other bacteria that is regularly exposed to radiation conditions believed to have existed on early Earth when a photochemical haze is believed to have been present. (Marc Kaufman)

    If and when she does find particularly interesting results in the gas measurements inside the anaerobic glove box, she says, she knows where to go.

    “I would hand the results to an astronomer. We could say that if a particular kind of exoplanet with a particular atmosphere had microbial life, this is the suite of gases we would expect to be emitted.”

    Those gases, Parenteau says, may be photochemically altered as they as they rise through the planet’s atmosphere to the upper levels where they could be detected by the telescopes of the future. But in the challenging and complex world of biosignatures, every bit of hard-won data is most valuable since it could some day lead to a discovery for the ages.

    See the full article here .


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    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 9:42 pm on May 18, 2018 Permalink | Reply
    Tags: , , , , , Know Thy Star Know Thy Planet: How Gaia is Helping Nail Down Planet Sizes, Many Worlds   

    From Many Worlds: “Know Thy Star, Know Thy Planet: How Gaia is Helping Nail Down Planet Sizes” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-05-17
    (This column was written by my colleague Elizabeth Tasker, now at the Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Sciences (ISAS). Trained as an astrophysicist, she researches planet and galaxy formation and also writes on space science topics. Her book, The Planet Factory, came out last year.)

    1
    Gaia’s all-sky view of our Milky Way and neighboring galaxies. (ESA/Gaia/DPAC) [Small and Large Magelaic Clouds are visible]

    Last month, the European Space Agency’s Gaia mission released the most accurate catalogue to date of positions and motions for a staggering 1.3 billion stars.

    ESA/GAIA satellite

    Let’s do a few comparisons so we can be suitably amazed. The total number of stars you can see without a telescope is less than 10,000. This includes visible stars in both the northern and southern hemispheres, so looking up on a very dark night will allow you to count only about half this number.

    The data just released from Gaia is accurate to 0.04 milli-arcseconds. This is a measurement of the angle on the sky, and corresponds to the width of a human hair at a distance of over 300 miles (500 km.) These results are from 22 months of observations and Gaia will ultimately whittle down the stellar positions to within 0.025 milli-arcseconds, the width of a human hair at nearly 680 miles (1000 km.)

    OK, so we are now impressed. But why is knowing the precise location of stars exciting to planet hunters?

    The reason is that when we claim to measure the radius or mass of a planet, we are almost always measuring the relative size compared to the star. This is true for all planets discovered via the radial velocity and transit techniques — the most common exoplanet detection methods that account for over 95% of planet discoveries.

    It means that if we underestimate the star size, our true planet size may balloon from being a close match to the Earth to a giant the size of Jupiter. If this is true for many observed planets, then all our formation and evolution theories will be a mess.

    The size of a star is estimated from its brightness. Brightness depends on distance, as a small, close star can appear as bright as a distant giant. Errors in the precise location of stars therefore make a big mess of exoplanet data.

    This issue has been playing on the minds of exoplanet hunters.

    In 2014, a journal paper authored by Fabienne Bastien [The Astrophysical Journal] from Vanderbilt University suggested that nearly half of the brightest stars observed by the Kepler Space Telescope are not regular stars like our sun, but actually are distant and much larger sub-giant stars. Such an error would mean planets around these stars are 20 – 30% larger than estimated, a particularly hard punch for the exoplanet community as planets around bright stars are prime targets for follow-up studies.

    Previous improvements in the accuracy of the measured radii and other properties of stars have already proved their worth. In 2017, a journal paper led by Benjamin Fulton [The Astrophysical Journal]at the University of Hawaii revealed the presence of a gap in the distribution of sizes of super Earths orbiting close to their star. Planets 20% and 140% larger than the Earth appeared to be common, but there was a notable dearth of planets around twice the size of our own.

    2
    Super Earth planets with orbits of less than 100 days seem to come in two different sizes. (NASA/Ames/Caltech/University of Hawaii. (B.J.Fulton))

    The most popular theory for this gap is that the peaks belong to planets with similar core sizes, but the planets with larger radii have deep atmospheres of hydrogen and helium. This would make the planets belonging to the smaller radii peak true rocky worlds, whereas the second peak would be mini Neptunes: the first evidence of a size distinction between these two regimes.

    This split in the small planet population was spotted due to improved measurements of planet radii based on higher precision stellar observations made using the Keck Observatory.


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    With a gap size of only half an Earth-radius, it had previously gone unnoticed due to the uncertainty in planet size measurements.

    Both the concern of a significant error in planet sizes and the tantalizing glimpse at the insights that could be achieved with more accurate data is why Gaia is so exciting.

    Launched on December 19, 2013, Gaia is a European Space Agency (ESA) space telescope for astrometry; the measurement of the position and motion of stars. The mission has the modest goal of creating a three-dimensional map of our galaxy to unprecedented precision.

    Gaia measures the position of stars using a technique known as parallax, which involves looking at an object from different perspectives.

    Parallax is easily demonstrated by holding up your finger and looking at it with one eye open and the other closed. Switch eyes, and you will see your finger moves in relation to the background. This movement is because you have viewed your finger from two different locations: the position of your left eye and that of your right.

    3
    Parallax is the apparent shift in the position of stars as the Earth orbits the sun. It can be used to determine distances between stars. (ESA/ATG medialab)

    The degree of motion depends on the separation between your eyes and the distance to your finger: if you move your finger further from your eyes, its parallax motion will be less. By measuring the separation of your viewing locations and the amount of movement you see, the distance to an object can therefore be calculated.

    Since stars are far more distant than a raised finger, we need widely separated viewing locations to detect the parallax. This can be done by observing the sky when the Earth is on opposite sides of its orbit. By measuring how far stars seem to move over a six month interval, we can calculate their distance and precisely estimate their size.

    This measurement was first achieved by Friedrich Wilhelm Bessel in 1838, who calculated the distance to the star 61 Cygni. Bessel estimated the star was 10.3 light years from the Earth, just 10% lower than modern measurements which place the star at a distance of 11.4 light years.

    However, measuring parallax from Earth can be challenging even with powerful telescopes. The first issue is that our atmosphere distorts light, making it difficult to measure tiny shifts in the position of more distant stars. The second problem is that the measured motion is always relative to other background stars. These more distant stars will also have a parallax motion, albeit smaller than stars closer to Earth.

    As a result, the motion measured and hence the distance to a star, will depend on the parallax of the more distant stars in the same field of view. This background parallax varies over the sky, leaving no way on Earth of creating a consistent catalogue of stellar positions.

    4
    The Gaia spacecraft’s billion-pixel camera maps stars and other objects in the Milky Way. (C. Carreau/ESA)

    These two conundrums are where Gaia has the advantage. Orbiting in space, Gaia simply avoids atmospheric distortion. The second issue of the background stars is tackled by a clever instrument design.

    Gaia has two telescopes that point 106.4 degrees apart but project their images onto the same detector. This allows Gaia to see stars from different parts of the sky simultaneously. The telescopes slowly rotate so that each field of view is seen once by each telescope and overlaid with a field 106.4 degrees either clockwise or counter-clockwise to its position. The parallax motion of stars during Gaia’s orbit can therefore be compared both with stars in the same field of view, and with stars in two different directions.

    Gaia repeats this across the sky, linking the fields of view together to globally compare stellar positions. This removes the problem of a parallax measurement depending on the motion of stars that just happen to be in the background.

    The result is the relative position of all stars with respect to one another, but a reference point is needed to turn this into true distances. For this, Gaia compares the parallax motion to distant quasars.

    Quasars are black holes that populate the center of galaxies and are surrounded by immensely luminous discs of gas. Being outside our Milky Way, the distance to quasars is so great that their parallax during the Earth’s orbit is negligibly small. Quasars are too rare to be within the field of view of most stars, but with stellar positions calibrated across the whole sky, Gaia can use any visible quasars to give the absolute distances to the stars.

    What did these precisely measured stellar motions do to the properties of the orbiting planets? Did our small worlds vanish or the intriguing division in the sizes of super Earths disappear?

    This was bravely investigated in a journal paper this month led by Travis Berger from the University of Hawaii. By matching the stars observed by Kepler to those in the Gaia catalogue, Berger confirmed that the majority of bright stars were indeed sun-like and not the suspected sub-giant population. However, the more precise stellar sizes were slightly larger on average, causing a small shift in the observed small planet radii towards bigger planets.

    5
    Planet radii derived from the new Gaia data and the Kepler (DR25) Stellar Properties Catalogue. Red points are confirmed planets while black points are planet candidates. Bottom panel shows the ratio between the two data sets. There is a small shift towards larger planets in the new Gaia data. (Figure 6 in Berger et al, 2018.)

    The same result was found in a parallel study led by Fulton, who found a 0.4% increase in planet radii from Gaia compared with the (higher precision than Kepler, but less precision than Gaia) results using Keck.

    The papers authored by Berger and Fulton investigated the split in super Earth sizes on short orbits, confirming that the two planet populations was still evident with the high precision Gaia data. Further exploration also revealed interesting new trends.

    Fulton noticed that two peaks in the super Earth population appear at slightly larger radii for planets orbiting more massive stars. This is true irrespective of the level radiation the planets are receiving from the star, ruling out the possibility that more massive stars are simply better at evaporating away atmospheres on bigger planets. Instead, this trend implies that bigger stars build bigger planets.

    Models proposed by Sheng Jin (Chinese Academy of Sciences) and Christoph Mordasini (the Max Planck Institute for Astronomy) in a paper last year [The Astrophysical Journal] proposed that the location of the split in the super Earth population could be linked to composition.

    Planets made of lighter materials such as ices would need a larger size to retain their atmospheres, compared to planet cores of denser rock. If the planet size at the population split marks the transition from large rocky worlds without thick atmospheres to mini-Neptunes enveloped in gas, then it corresponds to the size needed to retain that gas.

    Berger suggests that the gap between the planet populations seen in the new Gaia data is best explained by planets with an icy-rich composition. As these planets all have short orbits, this suggests these close-in worlds migrated inwards from a much colder region of the planetary system.

    The high precision planet radii measurements from Gaia seem to leave our planet population intact, but suggest new trends worth exploring. This will be a great job for TESS, NASA’s recently launched planet hunter that is preparing to begin its first science run this summer.

    NASA/TESS

    Gaia’s astrometry catalogue of stars will be ensuring we get the very best from this data.

    See the full article here .

    Please help promote STEM in your local schools.

    stem

    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 11:41 am on May 11, 2018 Permalink | Reply
    Tags: , , , , , First Mapping of Interstellar Clouds in Three Dimensions- a Key Breakthrough for Better Understanding Star Formation, Many Worlds   

    From Many Worlds: “First Mapping of Interstellar Clouds in Three Dimensions; a Key Breakthrough for Better Understanding Star Formation” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    From Many Worlds

    2018-05-11
    Marc Kaufman

    1
    This snakelike gas cloud (center dark area) in the constellation Musca resembles a skinny filament. But it’s actually a flat sheet that extends about 20 light-years into space away from Earth, an analysis finds. (Dylan O’Donnell, deography.com/WikiCommons)

    When thinking and talking about “astrobiology,” many people are inclined to think of alien creatures that often look rather like us, but with some kind of switcheroo. Life, in this view, means something rather like us that just happens to live on another planet and perhaps uses different techniques to stay alive.

    But as defined by NASA, and what “astrobiology” is in real scientific terms, is the search for life beyond Earth and the exploration of how life began here. They may seem like very different subjects but are actually joined at the hip; having a deeper understanding of how life originated on Earth is surely one of the most important set of clues to how to find it elsewhere.

    Those con-joined scientific disciplines — the search for extraterrestrial life and the extraordinarily difficult task of analyzing how it started here — together raise another most complex challenge.

    Precisely how far back do we look when trying to understand the origins of life? Do we look to Darwin’s “warm little pond?” To the Miller-Urey experiment’s conclusion that organic building blocks of life can be formed by sparking some common gases and water with electricity? To an understanding the nature and evolution of our atmosphere?

    The answer is “yes” to all, as well as to scores of additional essential dynamics of our galaxies. Because to begin to answer those three questions, we also have to know how planets form, the chemical make-up of the cosmos, how different suns effect different exoplanets and so much more.

    This is why I was so interested in reading about a breakthrough approach to understanding the shape and nature of interstellar clouds. Because it is when those clouds of gas and dust collapse under their own gravitational attraction that stars are formed — and, of course, none of the above questions have meaning without preexisting stars.

    In theory, the scope of astrobiology could go back further than star-formation, but I take my lead from Mary Voytek, chief scientist for astrobiology at NASA. The logic of star formation is part of astrobiology, she says, but the innumerable cosmological developments going back to the Big Bang are not.

    So by understanding something new about interstellar clouds — in this case determining the 3D structure of such a “cloud” — we are learning about some of the very earliest questions of astrobiology, the process that led over the eons to us and most likely life of some sort on the billions of exoplanets we now know are out there.

    2
    Cepheus B, a molecular cloud located in our Milky Galaxy about 2,400 light years from the Earth, provides an excellent model to determine how stars are formed. This composite image of Cepheus B combines data from the Chandra X-ray Observatory and the Spitzer Space Telescope.The Chandra observations allowed the astronomers to pick out young stars within and near Cepheus B, identified by their strong X-ray emission.
    Credits X-ray: NASA/CXC/PSU/K. Getman et al.; IRL NASA/JPL-Caltech/CfA/J. Wang et al.

    NASA/Chandra X-ray Telescope

    NASA/Spitzer Infrared Telescope

    So, what is an interstellar cloud?

    It’s the generic name given to an accumulation of gas, plasma, and dust in our and other galaxies, left over from galaxy formation. So an interstellar cloud is a denser-than-average region of the interstellar medium.

    Hydrogen is its primary component, and that hydrogen exists in a wide variety of states depending on the density, the age, the location and more of the cloud.

    Until recently the rates of reactions in interstellar clouds were expected to be very slow, with minimal products being produced due to the low temperature and density of the clouds. However, organic molecules were observed in the spectra that scientists would not have expected to find under these conditions, such as formaldehyde, methanol, and vinyl alcohol.

    The reactions needed to create such substances are familiar to scientists only at the much higher temperatures and pressures of earth and earth-based laboratories. The fact that they were found indicates that these chemical reactions in interstellar clouds take place faster than suspected, likely in gas-phase reactions unfamiliar to organic chemistry as observed on earth.

    What was newly revealed this week is that it is possible to determine the 3D structure of an interstellar cloud. The advance not only reveals the true structure of the molecular cloud Musca, which differs from previous assumptions in looking more like a pancake than a needle.

    But the two authors, astrophysicist Konstantinos Tassis of the University of Crete and Aris Tritsis, now a postdoctoral fellow at Australian National University, say their discovery will lead to a better understanding of the evolution of interstellar clouds in general. This, in turn, which will help astronomers answer the longstanding questions of how and why the enormous number and wild variety of stars exists in our galaxy and beyond.

    The two put together a video to help explain the science of Musca and its dimensions. The work was published in the journal Science, and here is their description of what the video shows:

    “The first part of the movie gives an overview of the problem of viewing star-forming clouds in 2D projection. The second part of the video shows the striations in Musca, and the process through which the normal mode spatial frequencies are recovered. The third part of the movie demonstrates how the apparently complex profiles of the intensity cuts through striations are reproduced by progressively summing the theoretically predicted normal modes. At this part of the video (1:30-1:52) the spatial frequencies are scaled to the frequency range of human hearing and are represented by the musical crescendo.”

    In an email, Tritsis said that this is the first time that the 3-dimensional coordinates of an interstellar cloud have been measured.

    “There have been other crude estimates of the 3D sizes of clouds that relied on many assumptions so this is the first time we were able to determine the size with such accuracy and certainty,” he wrote.

    “What we are after is the physics that controls the nature of the stars that will form. This physics will dictate how many star will form and with what masses, but it will also be responsible for shaping the cloud. Thus, this physics is encoded in the shape and that is why we are so interested about it.”

    Their pathway in to mapping a 3D cloud was the striations (wispy stripe-like patterns) they detected within the cloud. They show that these striations form by the excitation of fast magnetosonic waves (longitudinal magnetic pressure waves) – the cloud is vibrating, like a bell ringing after it has been struck.

    “What we have actually found is that the entire cloud oscillates just like waves on the surface of a pond,” he wrote in his email.

    “However, in this instance is not the surface of the water that is oscillating but the magnetic field that is threading the cloud. Furthermore, because these waves get trapped, they act like a fingerprint. They are unique and by studying their frequencies we can deduce the sizes of the boundaries that confined them.

    “It is the same concept as a violin and a cello making very different sounds. In a similar fashion, clouds with different shapes and sizes will vibrate differently. After having identify the frequencies of these oscillations we scaled them to the frequency range of human hearing to get the ‘song of Musca’!”

    By analyzing the frequencies of these waves the authors produce a model of the cloud, showing that Musca is not a long, thin filament as once thought, but rather a vast sheet-like or pancake structure that stretches 20 light-years away from Earth. (The cloud is some 27 light 490 and 650 light-years from Earth.)

    With the determination of its 3D nature, the scientists modeled a cloud that is ten times more spacious than earlier thought.

    From the 3D reconstruction, the authors were able to determine the cloud’s density. Tritsis and Tassis note that, with its geometry now determined, Musca can be used to test theoretical models of interstellar clouds.

    “Because of the fact that Musca is isolated and it is very ordered, it was the obvious choice for us to test our method,” Tritis wrote. “However, other clouds out there could also vibrate globally.

    “Knowing the exact dimensions of Musca, we can simulate it in great detail, calculate many different properties of this particular cloud based on different star formation models, and compare them with observations.

    “We believe that, with its 3D structure revealed, Musca will now act as a prototype laboratory to study star formation in greater detail than ever before. The Musca star formation saga is only now beginning, and this is a very exciting development that goes beyond this particular discovery.”

    And in that way, the discovery is very much a part of the long and broad sweep of astrobiology.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 9:23 pm on May 2, 2018 Permalink | Reply
    Tags: , , , , , Exoplanet Fomalhaut b On the Move, Many Worlds, ,   

    From Many Worlds: “Exoplanet Fomalhaut b On the Move” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2018-04-30
    Marc Kaufman

    1
    Enlarge on the full blog post or the full article and enjoy. Fomalhaut b on its very long (1,700 year) and elliptica orbit, as seen here in five images taken by the Hubble Space Telescope over seven years. The reference to “20 au” means that the bar shows a distance of 20 astronomical units, or 20 times the distance from the sun to the Earth. (Jason Wang/Paul Kalas; UC Berkeley)

    Direct imaging of exoplanets remains in its infancy, but goodness what a treat it is already and what a promise of things to come.

    Almost all of the 3,714 exoplanets confirmed so far were detected via the powerful but indirect transit and radial velocity methods — measures of slightly decreased light as a planet crosses in front of its star, or the measured wobble of a star caused by the gravitational pull of a planet.

    But now 44 planets have also been detected by telescopes — in space and on the ground — looking directly at distant stars. Using increasingly sophisticated coronagraphs to block out the blinding light of the stars, these tiny and often difficult-to-identify specks are nonetheless results that are precious to scientists and the public.

    To me, they make exoplanet science accessible as perhaps nothing else so far. Additionally, they strike me as moving — and I don’t mean in orbit. Rather, as when you see your own insides via x-rays or MRIs, direct imaging of exoplanets provides a glimpse into the otherwise hidden realities of our world.

    And in the years ahead – actually, most likely the decades ahead — this kind of direct imaging of our astronomical neighborhood will become increasingly powerful and common.

    This is how the astronomers studying the Fomalhaut system describe what you are seeing:

    “The Fomalhaut system harbors a large ring of rocky debris that is analogous to our Kuiper belt. Inside this ring, the planet Fomalhaut b is on a trajectory that will send it far beyond the ring in a highly elliptical orbit.

    “The nature of the planet remains mysterious, with the leading theory being the planet is surrounded by its own ring or a sphere of dust.”

    2
    An animated simulation of one possible orbit for Fomalhaut b derived from the analysis of Hubble Space Telescope data between 2004 and 2012, presented in January 2013 by astronomers Paul Kalas and James Graham of Berkeley, Michael Fitzgerald of UCLA and Mark Clampin of NASA/Goddard. (Paul Kalas)

    Fomalhaut b was first described in 2008 by Paul Kalas, James Graham and colleagues at the University of California, Berkeley. If not the first object identified through direct imaging — a brown dwarf failed star preceded it, as well as other objects that remain planet candidates — Fomalhaut was among the very first.

    Direct imaging-This false-color composite image traces the motion of the planet Fomalhaut b, a world captured by direct imaging. Credit: NASA, ESA, and P. Kalas (University of California, Berkeley and SETI Institute)

    The data came via the Advanced Camera for Surveys [ACS] on the Hubble Space Telescope.

    NASA/ESA Hubble ACS

    NASA/ESA Hubble Telescope

    But Fomalhaut b is an unusual planet by any standard, and that resulted in a lot of early debate about whether it really was a planet. Early efforts to confirm the presence of the planet failed, in part because the efforts were made in the infrared portion of the spectrum.

    Instead, Fomalhaut b had been detected only in the optical portion of the spectrum, which is uncommon for a directly imaged planet. More specifically, it reflects bluish light, which again is unusual for a planet. Some contended that the planet detection made by Hubble was actually a noise artifact.

    A pretty serious debate ensued in 2011 but by 2013 the original Hubble data had been confirmed by two teams and its identity as a planet was broadly embraced, although the noise of the earlier debate to some extent remains.

    As Kalas told me, this is probably because “no one likes to cover the end of a debate.” Nonetheless, he said, it is over.

    “Fomalhaut b at age 440 Myr (.44 billion years) is much older than the other directly imaged planets,” Kalas explained. “The younger the planet, the greater the infrared light it emits. Thus it is not particularly unusual that it is hard to image planets in the Fomalhaut system using infrared techniques.”

    Kalas believes that a ring system around the planet could be reflecting the light. Another possibility, he said, is that two dwarf planets collided and a compact dust cloud surrounding a dwarf planet is moving through the Fomalhaut system.

    That scenario would be very difficult to test, he said, but the alternate possibility of a Saturnian exoplanet with a ring is something that the James Webb Space Telescope will be able to explore.

    In any case, the issue of whether or not the possibly first directly-imaged planet is in fact a planet has been resolved for now.

    When the International Astronomical Union held a global contest to name some of the better known exoplanets several years ago, one selected for naming was Fomalhaut b, which also now has the name “Dagon.” The star Fomalhaut is the brightest in the constellation Pisces Australis — the Southern Fish — and Dagon was a fish god of the ancient Philistines.

    3
    This animated video of Beta Pictoris and its exoplanet was made using nine images taken with the Gemini Planet Imager over more than two years years. The planet is expected to come our from behind its star later this year, and the GPI team hopes to capture that event. (Jason Wang; UC Berkeley, Gemini Planet Imager Exoplanet Survey)

    NOAO Gemini Planet Imager on Gemini South


    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    While instruments on the W.M. Keck Observatory in Hawaii, the European Very Large Telescope in Chile and the Hubble Space Telescope have succeeded in directly imaging some planets, the attention has been most focused on the two relatively newcomers. They are the Gemini Planet Imager (GPI), now on the Gemini South Telescope in Chile [above] and funded largely by American organizations and universities, and the largely European Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument, also in Chile.


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    ESO VLT Platform at Cerro Paranal elevation 2,635 m (8,645 ft)

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level


    ESO/SPHERE extreme adaptive optics system and coronagraphic facility on the VLT, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level


    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    In real time, the two instruments correct for distorting atmospheric turbulences around Earth and also block the intense light of the host stars. Any residual incoming light is then scrutinized, and the brightest spots suggest a possible planet and can be photographed as such.

    The ultimate goal is have similar instruments improved until they are powerful enough to read the atmospheres of the planets through spectroscopy, which has been done so far only to a limited extent.

    Kalas, Graham and Jason Wang (a graduate student at Berkeley who put together the direct imaging movies ) are part of the GPI team, which since 2014 has been searching for Jupiter-sized and above planets orbiting some distance from their suns. The group is a member of NASA’s NExSS initiative to encourage exoplanet scientists from many disciplines to work together.

    While GPI has had successes detecting important exoplanets such as 51 Eridani b, it also studies already identified planets to increase understanding of their orbits and their characteristics.

    5
    The Gemini Planet Imager when it was being connected to the Gemini South Telescope in Chile. (Gemini Observatory)

    GPI has been especially active in studying the planet Beta Pictoris b, a super Jupiter discovered using data collected by the European Southern Observatory Very Large Telescope. While the data was first collected in 2003, it took five years to tease out the planet orbiting the young star and it took several more years to confirm the discovery and begin characterizing the planet.

    GPI has followed Beta Pictoris b for several years now, compiling orbital and other data used for video above.

    The planet is currently behind its sun and so cannot be observed. But James Graham told me that the planet is expected to emerge late this year or early next year. It remains unclear, Graham said, whether GPI will be able to capture that emergence because it will soon be moved from the Gemini telescope in Chile to the Gemini North Telescope on Hawaii. But he certainly hopes that it will be allowed to operate until the planet reappears.

    The planet 51 Eridani b was the first exoplanet discovered by the GPI and remains one of its most important. The planet is a million times fainter than its parent star and shows the strongest methane signature ever detected on an alien planet, which should yield additional clues as to how the planet formed.

    The four-year GPI campaign from Chile has not discovered as many Jupiter-and-greater sized planets as earlier expected. Graham said that may well be because there are fewer of them than astronomers predicted, or it may be because direct imaging is difficult to do.

    But Graham said the campaign is actually nowhere near over. Much of the data collected since 2014 remains to be studied and teased apart, and other Jupiters and super Jupiters likely are hidden in the data.

    Right now the exoplanet science community, and especially those active in direct imaging, are anxiously awaiting a decision by NASA, and then Congress, about the fate of the Wide Field Infrared Survey Telescope (WFIRST.)

    Designed to be the first space telescope to carry a coronagraph and consequently a major step forward for direct imaging, it was scheduled to be NASA’s big new observatory of the 2020s.

    But the Trump Administration cancelled the mission earlier this year, Congress then restored it but with the caveat that NASA had to provide a detailed plan for its science, its technology and its cost. That plan remains an eagerly-awaited work in progress.

    Meanwhile, here is another example of what direct imaging, with the help of soon-to-be Caltech postdoc Jason Wang, can provide. The video of the HR 8799 system went viral when first made public in early last year.

    6
    The four planet system orbiting the planet HR 8977, first partially identified in 2008 by Christian Marois of the National Research Council of Canada’s Herzberg Institute of Astrophysics and Bruce Macintosh of Stanford and others. The video was created in 2017 after all four planets had been identified via direct imagine and their orbits had been followed for some years. (Jason Wang of UC Berkeley/Christian Marois of NRC Herzberg.)

    The promise of direct imaging is enormous. The collected photons can be used for spectroscopy that can potentially tell scientists about a planet’s radius, mass, age, effective temperature, clouds, molecular composition, rotation rate and atmospheric dynamics.

    For a small, potentially habitable planet, direct imaging can measure surface temperate and pressure and determine whether it can support liquid water. It can also potentially determine if the atmosphere is in the kind of disequilibrium regarding oxygen, ozone and perhaps methane that signal the presence of life.

    But almost all this is in the future since none of the current instruments are powerful enough to collect that data.

    7
    University of California at Berkeley astronomy grad student Lea Hirsch at [the very important to me] Lick Observatory [at UCSC, on Mt Hamilton This was the location running the UCO system under the great Sandra Faber, who was a major contributor to the salvation of Hubble with COSTAR]. She will be going soon to Stanford University for a postdoc with Gemini Planet Imager Principal Investigator Bruce Macintosh.

    In the meantime, researchers such as Berkeley graduate student Lea Hirsch, soon to be a Stanford postdoc, are focused on using the strengths of the different detection methods to come up with constraints on exoplanetary characteristics (such as mass and radius) that one technique alone could not provide.

    For instance, the transit technique works best for identifying planets close to their stars, direct imaging is the opposite and radial velocity is best that detecting large and relatively close-in planets. Radial velocity gives a minimum (but not maximum) mass, while transits provide an exoplanet radius.

    Planet transit. NASA/Ames

    Radial velocity Image via SuperWasp http://www.superwasp.org/exoplanets.htm

    Radial Velocity Method-Las Cumbres Observatory

    What Hirsch would like to do is determine constraints (limits) on the size of exoplanets using both radial velocity measurements and direct imaging.

    As she explained, radial velocity will give that minimum mass, but nothing more in terms of size. But in an indirect way for now, direct imaging can provide some maximum mass.

    If, for instance, astronomers know through the radial velocity method that exoplanet X orbits a certain star and is twice the size of Jupiter, they can then look for it using direct imaging with confidence that something is there. Let’s say the precision of the imaging is such that if a planet six times the size of Jupiter was present they would — over a period of time — detect it.

    A detection would indeed be great and the planet’s mass (and more) would then be known. But if no planet is detected — as often happens — then astronomers still collect important information. They know that the planet they are looking for is less than six Jupiter masses. Since the radial velocity method already determined it was at least larger than two Jupiters, scientists would then know that the planet has a mass of between two and six Jupiters.

    “All the techniques in our toolkit {of exoplanet searching} have their strengths and weaknesses,” she said. “But using those techniques together is part of our future because there’s a potential to know much more.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 1:13 pm on April 13, 2018 Permalink | Reply
    Tags: A tiny bit of water ice known as ICE-VII inside several other deep diamonds, Diamonds, Diamonds and the bits of minerals gases and water encased in them offer a unique opportunity to probe the deepest regions of our planet, ICE-VII is a global phenomenon, Kimberlites, Lamproites, Many Worlds,   

    From Many Worlds: “Diamonds are a Deep-Earth Geologist’s Best Friend” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2018-04-13
    Marc Kaufman

    1
    Deep Earth diamond with garnet inside. These inclusions, which occur during the diamond formation process, provide not only a way to date the diamonds, but also a window into conditions in deep Earth when they wee formed. (M. Gress, VU Amsterdam)

    We all know that cut diamonds sparkle and shine, one of the great aesthetic creations from nature.

    Less well known is that diamonds and the bits of minerals, gases and water encased in them offer a unique opportunity to probe the deepest regions of our planet.

    Thought to be some of the oldest available materials found on Earth — some dated at up to 3.5 billion years old — they crystallize at great depth and under great pressure.

    But from the point of view of those who study them, it’s the inclusions that loom large because allow them to know the age and depth of the diamond’s formation. And some think they can ultimately provide important clues to major scientific questions about the origin of water on Earth and even the origin of life.

    The strange and remarkable subterranean world where the diamonds are formed has, of course, never been visited, but has been intensively studied using a variety of indirect measurements. And this field has in recent weeks gotten some important discoveries based on those diamond inclusions.

    First is the identification by Fabrizio Nestola of the University of Padua and colleagues of mineral that has been theorized to be the fourth most common on Earth, yet had never been found in nature or successfully synthesized in a laboratory. As reported in the journal Nature, the mineral is a variant of calcium silicate (CaSiO3), created at a high pressure that gives it a uniquely deep-earth crystal structure called “perovskite,” which is the name of a mineral, too.

    Mineral science does not allow a specimen to be named until it has actually been found in name, and now this very common form of mineral finally will get a name. But more important, it moves forward our understanding of what happens far below the Earth’s surface.

    2
    Where diamonds are formed and found on Earth. The super-deep are produced very far into the mantle and are pushed up by volcanoes and convection The lithospheric diamonds are from the rigid upper mantle and crust and the alluvial diamonds are those which came to the surface and then were transported elsewhere by natural forces. (Fabrio Nestola, Joseph R Smyth)

    The additional discovery was of a tiny bit of water ice known as ICE-VII inside several other deep diamonds. While samples of H2O ice have been identified in diamonds before, none were ICE-VII which is formed only under tremendous deep-Earth pressure.

    In addition to being a first, the ICE-VII discovery adds to the growing confidence of scientists that much H2O remains deep underground, with some inferring as much deep subsurface water as found in the surface oceans. That paper was authored by University of Nevada, Las Vegas geoscientist Oliver Tschauner and colleagues, and appeared in the journal Science.

    Diamonds are a solid form of carbon with a distinctive cubic crystal structure. They are generally formed at depths of 100 to 150 miles in the Earth’s mantle, although a few have come from as deep as 500 to 600 miles down.

    Those super-deep diamonds form in a cauldron up to 1,000 degrees F and at 240,000 times the atmospheric pressure at sea level. They are made from carbon-containing fluids that dissolve minerals and replace them with what over time become diamonds.

    Much more recently (tens to hundreds of million years ago), the would have been pushed to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites (blue-tinged in color and coarse grained) and lamproites (rich in potassium and also from deep in the mantle.)

    The mantle – which makes up more than 80 percent of the Earth’s volume – is made of silicate minerals containing iron, aluminum, and calcium among others. Blue diamonds are that color because of the presence of the trace mineral boron in the mantle.

    And now we can add water the list as well.

    3
    Professor of Mineralogy Fabrizio Nestola while a visiting professor at the University of Alberta. One of his collaborators on the recent high-pressure calcium silicate paper is Alberta professor Graham Pearson. Here Nestola presented on his recent work in advances in X-ray crystallography on diamonds and their inclusions.

    Nestola, who has been conducting his deep-Earth studies with a major grant from the European Union, is eager to take his already substantial work much further.

    First he is looking for answers to the basic question of the origin of water on Earth (from incoming asteroids and comets or an integral component at formation) and ultimately to the origin of life. Diamonds, he says, offer a pathway to study both subjects.

    For water, his goal is to find a range of diamond-encircled samples that can be measured for their deuterium to hydrogen ratio — a key diagnostic to determining where in the solar system an object and its H2O originated, Deuterium, or heavy hydrogen, is an isotope of hydrogen with an extra neutron.

    4
    An example of a super-deep diamond from the Cullinan Mine, where scientists recently discovered a diamond that provides first evidence in nature of Earth’s fourth most abundant mineral–calcium silicate perovskite. (Petra Diamonds)

    As the number of diamond samples with evidence of water grows, Nestola says it will be possible to determine how the D/H ratio changes over time and as a result gain a better understanding of where the Earth’s water came from.

    When it comes to clues regarding the origin of life, Nestola will be looking for carbon isotopes in the diamonds.

    Regarding the high-pressure form of calcium silicate that he and his colleagues recently identified, Nestola said that many scientists have tried to reproduce it in their labs but have found there’s no way to keep the mineral stable at surface pressures. So the discovery had to be made from inside the nearly impermeable container of a diamond.

    The diamond that contained the common yet never before found mineral was just 0.031 millimeters across, is also a super-rare specimen.

    Adding to the interest in this discovery is that other trace minerals and elements found in the inclusion strongly suggest that the material was once on the Earth’s crust. The logic is that it would have been subducted as a function of plate tectonics billions of years ago, then encased in a forming diamond deep in the mantle, and ultimately sent back up near the surface again.

    Most diamonds are born much closer to Earth’s surface, between 93 and 124 miles deep. But this particular diamond would have formed at a depth of around 500 miles, the researchers said.
    “The diamond keeps the mineral at the pressure where it was formed, and so it tells us a lot about the ancient deep-Earth environment,” Nestola said. “This is how we’ll learn about deep Earth and ancient Earth. And we hope about those central origin questions too.”

    5
    A South African diamond crystal on kimberlite, an igneous rock formed deep in the mantle and famous for the frequency with which it contains diamonds. (Shutterstock)

    For his ICE-VII study, Tschauner used diamonds found in China, the Republic of South Africa, and Botswana that had been pushed up from inside Earth. He believes the range of locations strongly suggests that the presence of the ICE-VII is a global phenomenon.

    Scientists theorize the diamonds used in the study were born in the mantle under temperatures reaching more than 1,000-degrees Fahrenheit.

    “One essential question that we are working on is how much water is actually stored in the mantle. Is it oceans, or just a bit?” Tschauner said. “This work shows there can be free excess fluids in the mantle, which is important.”

    The mantle is a vast reservoir of mostly solid and very hot rock under immense pressure beneath the crust. It has an upper layer, a transition zone, and a lower layer. The upper layer has a little bit of water, but scientist estimate 10 times more water may be in the transition zone, where the enormous pressure is changing crystal structures and minerals seem to be more soluble. Minerals in the lower layer don’t seem to hold water as well.

    There’s already evidence of water in the mantle in different forms, such as water that has been broken up and incorporated into other minerals. But these diamonds contain water frozen into a special kind of ice crystal. There are lots of different ways water can crystallize into ice, but ice-VII is formed under higher pressures.

    While the diamond was forming, it must have encapsulated some liquid water from around the transition zone. The high temperatures prevented this water from crystalizing under the high pressures. As geologic activity moved the diamonds to the surface, they maintained the high pressures in their rigid crystal structures—but the temperature dropped. This would have caused the water to freeze into ice-VII.

    The discovery of Ice-VII in the diamonds is the first known natural occurrence of the aqueous fluid from the deep mantle. Ice-VII had been found as a solid in prior lab testing of materials under intense pressure. As described before, it begins as a liquid in the mantle.

    “These discoveries are important in understanding that water-rich regions in the Earth’s interior can play a role in the global water budget and the movement of heat-generating radioactive elements,” Tschauner said.

    This discovery can help scientists create new, more accurate models of what’s going on inside the Earth, specifically how and where heat is generated under the Earth’s crust.

    In other words: “It’s another piece of the puzzle in understanding how our planet works,” Tschauner said.

    6
    A polished and enlarged section of the Esquel pallasite meteoritemeteorite that delivered tiny nano-diamonds to Earth. This is a common occurrence, as there is believed to be substantial amounts of high-pressure carbon in the galaxies, and thus some diamonds. (Trustees of the NHM, London)

    Diamonds are by no means exclusive to Earth. Not only are they contained in minute form in meteorites, but atmospheric data for the gas giant planets indicates that carbon is abundant in its famous crystal form elsewhere in the solar system and no doubt beyond.

    Lightning storms turn methane into sooty carbon which, as it falls, hardens under great pressure into graphite and then diamond.

    These diamond “hail stones” eventually melt into a liquid sea in the planets’ hot cores, researchers told a an American Astronomical Society conference in 2013.

    The biggest diamonds would likely be about a centimeter in diameter – “big enough to put on a ring, although of course they would be uncut,” says Dr Kevin Baines, of the University of Wisconsin-Madison and NASA’s Jet Propulsion Laboratory.

    “The bottom line is that 1,000 tons of diamonds a year are being created on Saturn. People ask me – how can you really tell? Because there’s no way you can go and observe it.

    “It all boils down to the chemistry. And we think we’re pretty certain.”

    These potential raining diamonds, and all sorts of other extraterrestrial diamonds including possible diamond worlds, doubtless have their own scientifically compelling and important stories to tell.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 9:12 am on March 15, 2018 Permalink | Reply
    Tags: , , , , Many Worlds, NASA Space Initiative in Tatters, Space Science In Peril   

    From Many Worlds: “Space Science In Peril” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    1

    NASA’s decades-long success at enabling ground-breaking discoveries about our planet, our solar system, our galaxy, our origins and the billions of other planets out there is one of the crown jewels of our nation’s collective inventiveness and will, and surely of our global soft power.

    Others have of course made major contributions as well. But from the Viking Mars landings of the 1970s on to the grand space observatories Hubble and Spitzer and Chandra, to the planetary explorations such as Cassini (Saturn), Galileo and Juno (Jupiter), New Horizons (Pluto and beyond) and Curiosity (Mars), to the pioneering exoplanet census of Kepler, the myriad spacecraft enhancing our understanding of our own planet and the sun, and the pipeline confidently filled with of missions to come, NASA has been the consistent and essential world leader.

    NASA/Viking 1 Lander

    NASA/ESA Hubble Telescope

    NASA/Spitzer Infrared Telescope

    NASA/Chandra Telescope

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    NASA/New Horizons spacecraft

    NASA/Mars Curiosity Rover

    NASA/Kepler Telescope

    What we know of our world writ large has just exploded in these decades, and we’re far richer for it.

    But of late, the future of these efforts to ever expand our knowledge of the logic and make-up of our universe has become worryingly unclear.

    First there are the recently revealed new problems with the James Webb Space Telescope, initially scheduled to launch years ago and now reportedly unlikely to meet its launch date next year. It is also over budget again and under serious threat.

    NASA/ESA/CSA Webb Telescope annotated

    This news came as Congress wrestled with the White House decision to scuttle the WFIRST dark energy, planet and star formation, and exoplanet mission, planned as NASA’s major flagship mission of the 2020s.

    NASA/WFIRST

    And perhaps most worrisome, NASA now wants to fold its Space Technology Mission Directorate into the Human Exploration and Operations Directorate, surely to support the administration’s goal of setting up a human colony on the moon.

    This is an Apollo-sized, many-year and very costly effort that would have to take funds away from potential space science missions unless the NASA budget was growing substantially. But the proposed 2019 NASA budget would cap spending for the next four years.

    Might our Golden Era of space discovery be winding down?

    First the JWST situation. The telescope, far more powerful and complex than anything sent into space, is expected to open up new understandings about the origins of the universe, xxx, and exoplants.

    But late last month, the General Accounting Office released a report that said:

    “The James Webb Space Telescope, the planned successor to the Hubble Telescope, is one of NASA’s most complex and expensive projects.

    NASA recently announced that JWST’s launch would be delayed several months, from October 2018 to no later than June 2019, because components of the telescope are taking longer to integrate than planned.

    Based on the amount of work NASA has to complete before JWST is ready to launch, we found that it’s likely the launch date will be delayed again. If that happens, the project will be at risk of exceeding the $8 billion cost cap set by Congress.”

    That cost cap was put in place in 2011, after a House subcommittee voted to end the project entirely because of overruns. The full Congress then agreed to continue funding but only to the $8 billion mark.

    Will Congress agree to more money if the agency needs more time to complete launch preparations? Or will the money have to come out of the existing NASA budget? It seems highly unlikely that the project will be halted but all the overruns and delays — often based on the difficulties associated with new technologies — cast a pall of sorts over plans for big space science projects in the decades ahead.

    The long-term ramifications of the JWST delays and overruns could be substantial. The space community began pushing in the 1970s for the launching of a new grand space observatory every decade, and the science and public engagement results have been tremendous. The process of selecting a grand observatory mission for the 2030s is underway now, with teams of scientists and engineers feverishly gathering ideas, data, technology know-how and cost predictions for four contenders.

    Two focus on astrophysics and questions about the make-up and origins of the universe and two on exoplanets and the effort to determine if some might have the conditions that could support life and, perhaps, might actually do so. Those two are the Habitable-Exoplanet Imaging Mission (HabEx), and Large Ultraviolet-Optical-Infrared Surveyor (LUVOIR).

    NASA Habitable Exoplanet Imaging Mission (HabEx) The Planet Hunter

    NASA Large UV Optical Infrared Surveyor (LUVOIR)

    Both are likely to be quite costly, and LUVOIR in particular. But unlike HabEx, LUVOIR would have the power and kinds of instruments needed to determine not only if life might be possible on an exoplanet, but potentially if that life is present. It would be a Hubble on steroids — a dream observatory that would have the ability to transform (or greatly deepen) space science.

    But the enormous promise of a LUVOIR or HabEx helps explain some of the scientific dismay about the administration’s decision to cancel the “flagship” observatory of the 2020s, the Wide Field Infrared Survey Telescope (WFIRST.)

    Selected in 2010 by the space science community and later the National Academy of Sciences as the priority mission of the 2020s, WFIRST would focus on the nature of dark matter, the expansion of the universe, and would push forward some exoplanet observing as well.

    So cancelling of the mission — if Congress now allows that to happen — would not only eliminate an important observatory that would keep NASA in the forefront of space astrophysics, but would also send a message that even being selected as the top priority space mission for the decade does not provide ironclad protection.

    At space subcommittee hearing of the House Science Committee with NASA Acting Administrator Robert Lightfoot, Rep. Ami Bera (D. Calif.) voiced that concern earlier this month.

    “The decadal survey has served us well, and not looking at this scientific-based prioritization and moving away from that can certainty set a dangerous precedent,” Bera warned.

    The elephant in the room in this discussion is easy to identify — the administration’s well-publicized desire to set up an on-going human colony of Americans on the moon, or at least to get astronauts back on the lunar surface during the 2020s. The stated goals are exploration, commercial and international joint ventures and geopolitics, with seldom a mention of science.

    The proposed 2019 budget does not set aside a great deal of money for the moon project, but it does do something that worries many former NASA leaders and NASA followers — the funding for space technology and innovation ($1 billion) will now be housed within the human exploration directorate, as “Exploration Research and Technology.”

    The stated logic is that technological advancement should be directed toward human space exploration.

    “The FY 2019 budget is restructured to align with the Administration’s new space exploration policy by consolidating and refocusing existing NASA technology development activities on space exploration,” the budget document reads.

    This will inevitably take some funds away from technology projects that could be useful across NASA’s directorates, but more important sets the stage for a ramp up in funding for moon missions in the years ahead. And since the proposed 2019 budget would cap NASA funds for the next four years, other NASA programs would have to suffer — most notably Earth sciences and other science exploration unrelated to the moon.

    Seldom discussed by those excited by the prospect of continuing the legacy of the Apollo program and having Americans return to the moon is that Apollo was extraordinarily expensive and required great national sacrifice.

    During the 1960s the NASA budget (which was directed in large part into the Mercury and Apollo manned missions) took up as much as four percent of the federal budget (the equivalent of $40 billion today.) For six years it took up three percent or more of the budget. The NASA budget is now at its lowest point since 1959 as a percentage of the federal budget since — less than one-half of one percent of the budget — and provides less than $20 billion and has for decades.

    It seems pretty clear that ambitious humans-on-the-moon project would mean fewer Cassinis, fewer Hubbles, fewer Keplers.

    Another sign of the lowering profile of NASA science is the proposal in the 2019 budget to launch the other NASA flagship science mission of the 2020s, the flyby of Jupiter’s moon Europa, on a commercial heavy-lift rocket rather than NASA’s Space Launch System. The SLS was sold to Congress as the vehicle that could send spacecraft speedily to outer planets, but now both production delays and a desire to quickly get astronauts into space on the SLS has made that far less likely and some years further out, if at all.

    Heavy lift rockets other than SLS—including SpaceX’s Falcon Heavy and the Delta IV from United Launch Alliance —lack the power to blast the Europa Clipper directly from Earth to Jupiter. A conventional rocket would rely on three gravity assists from Earth and one from Venus, increasing the transit time from about 3 years to at least 6 years.

    Missions happen when they are a priority, and clearly now not just a scientific priority. Nothing is settled, but the warning signs are there that the moon program will force space science down the priority list unless NASA suddenly gets a lot more money.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 7:48 am on February 19, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds, Northern Lights   

    From Many Worlds: “The Northern Lights, the Magnetic Field and Life” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2018-02-19
    Marc Kaufman

    1
    Northern Lights over a frozen lake in Northern Norway, inside the Arctic Circle near Alta. The displays can go on for hours, or can disappear for days or weeks. It all depends on solar flares. (Ongajok.no)

    May I please invite you to join me in the presence of one of the great natural phenomena and spectacles of our world.

    Not only is it enthralling to witness and scientifically crucial, but it’s quite emotionally moving as well.

    Why? Because what’s before me is a physical manifestation of one of the primary, but generally invisible, features of Earth that make life possible. It’s mostly seen in the far northern and far southern climes, but the force is everywhere and it protects our atmosphere and us from the parched fate of a planet like Mars.

    I’m speaking, of course, of the northern lights, the Aurora Borealis, and the planet’s magnetic fields that help turn on the lights.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

    My vantage point is the far northern tip of Norway, inside the Arctic Circle. It’s stingingly cold in the silent woods, frozen still for the long, dark winter, and it’s always an unpredictable gift when the lights show up.

    But they‘re out tonight, dancing in bright green and sometimes gold-tinged arches and spotlights and twirling pinwheels across the northerly sky. Sometimes the horizon glows green, sometimes the whole sky fills with vivid green streaks.

    It can all seem quite other-worldly. But the lights, of course, are entirely the result of natural forces.

    2
    Northern Lights over north western Norway. Most of the lights are green from collisions with oxygen, but some are purple from nitrogen. © Copyright George Karbus Photography.

    It has been known for some time that the lights are caused by reactions between the high-energy particles of solar flares colliding in the upper regions of our atmosphere and then descending along the lines of the planet’s magnetic fields. Green lights tell of oxygen being struck at a certain altitude, red or blue of nitrogen.

    But the patterns — sometimes broad, sometimes spectral, sometimes curled and sometimes columnar — are the result of the magnetic field that surrounds the planet. The energy travels along the many lines of that field, and lights them up to make our magnetic blanket visible.

    Such a protective magnetic field is viewed as essential for life on a planet, be it in our solar system or beyond.

    But a magnetic field does not a habitable planet make. Mercury has a strong magnetic field and is certainly not habitable. Mars also once had a weak magnetic field and stir has some remnants on its surface. But it fell apart early in the planet’s life, and that may well have put a halt to the emergence or evolution of living things on the otherwise habitable planet.

    I will return to some of the features of the northern lights and the magnetism is makes visible, but this is also an opportunity to explore the role of magnetism in biology itself.

    This was a quasi-science for some time, but more recently it has been established that migrating birds and fish use magnetic sensors (in their beaks or noses, perhaps) to navigate northerly and southward paths.

    3
    Graphic from Science Magazine.

    But did you know that bacteria, insects and mammals of all sorts appear to have magnetic compasses as well? They can read the magnetism in the air, or can read it in the rocks (as in the case of some sea turtles.) A promising line of study, pioneered by scientists including geobiologist Joseph Kirschvink of the California Institute of Technology (Caltech) and the Earth-Life Science Institute (ELSI) in Tokyo, is even studying potentially remnant magnetic senses in humans.

    “There no doubt now that magnetic receptors are present in many, many species, and those that don’t have it probably lost it because it wasn’t useful to them,” he told me. “But there’s good reason to say that the magnetic sense was most likely one of the earliest on Earth.”

    But how does it work for animals? How do they receive the magnetic signals? This is a question of substantial study and debate.

    One theory states that creatures use the iron mineral magnetite — that they can produce and consume – to pick up the magnetic signals. These miniature compass needles sit within receptor cells, either near a creature’s nose or in the inner ear.

    Another posits that magnetic fields trigger quantum chemical reactions in proteins called cryptochromes, which have been found in the retina. But no one has determined how they might send signals and information to the brain.

    Kirschvink was part of a team that Earth’s magnetic field dates back to the Archean era, 3 to 3.5 billion years ago. “My guess is that magnetism has been a major influence in the biosphere since then, the biological ability to make magnetic materials.”

    He said that when the sun is particularly angry and active, the geomagnetic storms that occur around the planet seem to interfere with these magnetic responses and that animals don’t navigate as well.

    Kirschvink sees magnetism as a possibly important force in the origin of life. Magnetite that is lined up like beads on a chain has been detected in bacteria, and he says it may have provided an evolutionary pathway for structure that allowed for the rise of eukaryotes — organisms with complex cells, or a single cell with a complex structures.

    Kirschvink and his team are in the midst of a significant study of the effects of geomagnetism on humans, and the pathways through which that magnetism might be used.

    That’s rather a long way from some of the early biomagnetism discoveries, which involved the gumboot chiton. A mollusk relative of the snail and the limpet, the gumboot chiton holds on to rocks in the shallow water and uses its magnetite-covered teeth to scrape algae from rocks. The teeth are on a tongue-like feature called the radula and those teeth are capped with so much magnetite that a magnet can pick up the foot-long gumboot chiton.

    4
    The underside of a gumboot chiton, with its teeth covered with magnetite, can be lifted up with a magnet. No image credit.

    Back at most northern and southerly regions of the planet, where the magnetic field lines are most concentrated, the lights put on their displays for ever larger audiences of people who want to experience their presence.

    We had part of one night of almost full sky action, with long arches, curves large and small, waves, spotlights , shimmers and curtains. It had the feel of a spectacular fireworks display, but magnified in its glory and power and, of course, entirely natural. (I hope to post images taken by others that night which, alas, were not captured by my camera because the battery froze in the 10 degree cold.)

    Our grand night was one of the special ones when the colors (almost all greens, but some reds too) were so bright that their shapes and movements were easy to see with the naked eye.

    Good cameras (especially those with batteries that don’t freeze) see and capture a much broader range of the northern light presence. The horizon, for instance, can appear just slightly green to the naked eye, but will look quite brightly green in an image.

    Thanks to the National Oceanic and Atmospheric Administration, the National Weather Service and NASA, forecasting when and where the lights are likely to be be active in the northern and southern (the Aurora Australis) polar regions.

    This forecasting of space weather revolves around the the eruption of solar flares. The high-energy particles they send out collide with electrons in our upper atmosphere accelerate and follow the Earth’s magnetic fields down to the polar regions.

    5
    Models based on measuring solar flares, or coronal mass ejections, coming from sunspots that rotate and face Earth every 27 or 28 days. Summer months in the northern hemisphere often make the sky too light for the lights to be seen, so the long winter nights are generally the best time to see them. But they do appear in summer, too. (NOAA).

    In these collisions, the energy of the electrons is transferred to the oxygen and nitrogen and other elements in the atmosphere, in the process exciting the atoms and molecules to higher energy states. When they relax back down to lower energy states, they release their energy in the form of light. This is similar to how a neon light works.

    The aurora typically forms 60 to 400 miles above Earth’s surface.

    All this is possible because of our magnetic field, which scientists theorize was created and is sustained by interactions between super-hot liquid iron in the outer core of the Earth’s center and the rotation of the planet. The flowing or convection of liquid metal generates electric currents and the rotation of Earth causes these electric currents to form a magnetic field which extends around the planet.

    If the magnetic field wasn’t present those highly charged particles coming from the sun, the ones that set into motion the processes that produce the Northern and Southern Lights, would instead gradually strip the atmosphere of the molecules needed for life.

    This intimate relationship between the magnetic field and life led to me ask Kirschvink, who has been studying that connection for decades, if he had seen the northern or southern lights.

    No, he said, he’d never had the chance. But if ever in the presence of the lights, he said he know exactly what he would do: take out his equipment and start taking measurements and pushing his science forward.

    6
    Northern Lights in northern Norway, near Alta. Sometimes they dance for minutes, sometimes for hours, but often they never come at all. It all depends on the rotation of the sun; if and when it may be shooting out high-energy solar flares. (Wiki Commons)

    See the full article here .

    Please help promote STEM in your local schools.

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    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
  • richardmitnick 2:29 pm on January 29, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds, National Academy of Sciences decadal study   

    From Many Worlds: “False Positives, False Negatives; The World of Distant Biosignatures Attracts and Confounds” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2018-01-29
    Marc Kaufman

    1
    This artist’s illustration shows two Earth-sized planets, TRAPPIST-1b and TRAPPIST-1c, passing in front of their parent red dwarf star, which is much smaller and cooler than our sun. NASA’s Hubble Space Telescope looked for signs of atmospheres around these planets. (NASA/ESA/STScI/J. de Wit, MIT)

    NASA/ESA Hubble Telescope

    What observations, or groups of observations, would tell exoplanet scientists that life might be present on a particular distant planet?

    The most often discussed biosignature is oxygen, the product of life on Earth. But while oxygen remains central to the search for biosignatures afar, there are some serious problems with relying on that molecule.

    It can, for one, be produced without biology, although on Earth biology is the major source. Conditions on other planets, however, might be different, producing lots of oxygen without life.

    And then there’s the troubling reality that for most of the time there has been life on Earth, there would not have been enough oxygen produced to register as a biosignature. So oxygen brings with it the danger of both a false positive and a false negative.

    Wading through the long list of potential other biosignatures is rather like walking along a very wet path and having your boots regularly pulled off as they get captured by the mud. Many possibilities can be put forward, but all seem to contain absolutely confounding problems.

    With this reality in mind, a group of several dozen very interdisciplinary scientists came together more than a year ago in an effort to catalogue the many possible biosignatures that have been put forward and then to describe the pros and the cons of each.

    “We believe this kind of effort is essential and needs to be done now,” said Edward Schwieterman, an astronomy and astrobiology researcher at the University of California, Riverside. “Not because we have the technology now to identify these possible biosignatures light years away, but because space and ground telescopes of the future need to know what to look for and what kind of equipment they will need to make the potentially find it.

    “It’s part of the very long road to learning whether or not we are alone in the universe.”

    2
    Artistic representations of some of the exoplanets detected so far with the greatest potential to support liquid surface water, based on their size and orbit. All of them are larger than Earth and their composition and habitability remains unclear. They are ranked here from closest to farthest from Earth. Mars, Jupiter, Neptune an Earth are shown for scale on the right. (Planetary Habitability Laboratory, managed by the University of Puerto Rico at Arecibo.)

    The known and inferred population of exoplanets — even small rocky exoplanets — is now so vast that it’s tempting to assume that some support life and that some day we’ll find it. After all, those billions of planets are composed of same basic chemical elements as Earth and are subject to the same laws of physics.

    That assumption of life widespread in the galaxies may well turn out to be on target. But assuming this result, and proving or calculating a high probability of finding extraterrestrial life, are light years apart.

    The timing of this major community effort is hardly accidental. There is a National Academy of Sciences effort underway to review progress in the science of reading possible biosignatures from distant worlds, something that I wrote about recently.

    The results from the NAS effort will in term flow into the official NAS decadal study that will follow and will recommend to Congress priorities for the next ten or twenty years. In addition, two NASA-ordered science and technology definition teams are currently working on architectures for two potential major NASA missions for the 2030s — HabEx (the Habitable Exoplanet Imaging Mission) and Luvoir (the Large Ultraviolet/Optical/Infrared Surveyor.)

    The two mission proposals, which are competing with several others, would provide the best opportunity by far to determine whether life exists on other distant planets.

    With these formal planning and prioritizing efforts as a backdrop, NASA’s Nexus for Exoplanet System Science (NExSS) called for a biosignatures workshop in the fall of 2016 and brought together scientists from many disciplines to wrestle with the subject. The effort led to the white paper submitted to NAS and will result in publication of as many as five much more detailed papers in the journal Astrobiology this spring. The overview paper with Schwieterman as first author, which has already been made available to the community for peer review, is expected to lead off the package.

    So what did they find? First off, that Earth has to be their guide.

    “Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet,” the paper reads. “Aided by the universality of the laws of physics and chemistry, we turn to Earth’s biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere.

    Considering the insights gained from modern and ancient Earth, and the broader array of hypothetical exoplanet possibilities, we have compiled a state-of-the-art overview of our current understanding of potential exoplanet biosignatures including gaseous, surface, and temporal biosignatures.”

    In other words, potential biosignatures in the atmosphere, on the ground, and that become apparent over time. We’ll start with the temporal:

    4
    These vegetation maps were generated from MODIS/Terra measurements of the Normalized Difference Vegetation Index (NDVI). Significant seasonal variations in the NDVI are apparent between northern hemisphere summer and winter. (Reto Stockli, NASA Earth Observatory Group, using data from the MODIS Land Science Team.)

    NASA AQUA MODIS

    NASA/Terra satellite

    Vegetation is probably clearest example of how change-over-time can be a biosignature. As these maps show and we all know, different parts of the Earth have different seasonal colorations. Detecting exoplanetary change of this sort would be a potentially strong signal, though it could also have some non-biological explanations.

    If there is any kind of atmospheric chemical corroboration, then the time signal would be a strong one. That corroboration could come in seasonal modulations of biologically important gases such as CO2 or O2. Changes in cloud cover and the periodic presence of volcanic gases can also be useful markers over time.

    Plant pigments themselves which have been proposed as a surface biosignature. Observed in the near infrared portion of the electromagnetic spectrum, the pigment chlorophyll — the central player in the process of photosynthesis — shows a sharp dropoff in reflectance at a particular wavelength. This abrupt change is called the “red edge,” and is a measurement known to exist only which chlorophyll engaged in photosynthesis.

    So the “red edge,” or parallel dropoffs in reflectance of other pigments on other planets, is another possible biosignature in the mix.

    And then there is “glint,” reflections from exoplanets that come from light hitting water.

    5
    True-color image from a model (left) compared to a view of Earth from the Earth and Moon Viewer (http://www.fourmilab.ch/cgi-bin/Earth/). A glint spot in the Indian Ocean can be clearly seen in the model image.

    Since biosignature science essentially requires the presence of H2O on a planet, the clear detection of an ocean is part of the process of assembling signatures of potential life. Just as detecting oxygen in the atmosphere is important, so too is detecting unmistakable surface water.

    But for reasons of both science and detectability, the chemical make-up exoplanet atmospheres is where much biosignature work is being done. The compounds of interest include (but are not limited to) ozone, methane, nitrous oxide, sulfur gases, methyl chloride and less specific atmospheric hazes. All are, or have been, associated with life on Earth, and potentially on other planets and moons as well.

    The Schwieterman et al review looks at all these compounds and reports on the findings of researchers who have studied them as possible biosignatures. As a sign of how broadly they cast their net, the citations alone of published biosignature papers number more than 300.

    (Sara Seager and William Bains of MIT, both specialists in exoplanet atmospheres, have been compiling a separate and much broader list of potential biosignatures, even many produced in very small quantities on Earth. Bains is a co-author on one of the five biosignature papers for the journal Astrobiology.)

    All this work, Schwieterman said, will pay off significantly over time.

    “If our goal is to constrain the search for life in our solar neighborhood, we need to know as much as we possibly can so the observatories have the necessary capabilities. We could possibly save hundreds of millions or billions of dollars by constraining the possibilities.”

    “The strength of this compilation is the full body of knowledge, putting together what we know in a broad and fast-developing field,” Schwieterman said. ”

    He said that there’s such a broad range of possible biosignatures, and so many conditions where some might be more or less probable, that’s it’s essential to categorize and prioritize the information that has been collected (and will be collected in the future.)

    “We have a lot of observations recorded here, but they will all have their ambiguities,” he said. “Our goal as scientists will be to take what we know and work to reduce those ambiguities. It’s an enormous task.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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 5:31 pm on January 15, 2018 Permalink | Reply
    Tags: , , , , , Many Worlds   

    From Many Worlds: “Putting Together a Community Strategy To Search for Extraterrestrial Life” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2018-01-15
    Marc Kaufman

    1
    The scientific search underway for life beyond Earth requires input from many disciplines and fields. Strategies forward have to hear and take in what scientists in those many fields have to say. (NASA)

    Behind the front page space science discoveries that tell us about the intricacies and wonders of our world are generally years of technical and intellectual development, years of planning and refining, years of problem-defining and problem-solving. And before all this, there also years of brainstorming, analysis and strategizing about which science goals should have the highest priorities and which might be most attainable.

    That latter process is underway now in regarding the search for life in the solar system and beyond, with numerous teams of scientists tackling specific areas of interest and concern and turning their group discussions into white papers. In this case, the white papers will then go on to the National Academy of Sciences for a blue-ribbon panel review and ultimately recommendations on which subjects are exciting and mature enough for inclusion in a decadal survey and possible funding.

    This is a generally little-known part of the process that results in discoveries, but scientists certainly understand how they are essential. That’s why hundreds of scientists contribute their ideas and time — often unpaid — to help put together these foundational documents.

    With its call for extraterrestrial habitability white papers, the NASA got more than 20 diverse and often deeply thought out offerings. The papers will be studied now by an ad hoc, blue ribbon committee of scientists selected by the NAS, which will have the first of two public meetings in Irvine, Calif. on Jan. 16-18.

    Then their recommendations go up further to the decadal survey teams that will set formal NASA priorities for the field of astronomy and astrophysics and planetary science. This community-based process that has worked well for many scientific disciplines since they began in the late 1950s.

    I’m particularly familiar with two of these white paper processes — one produced at the Earth-Life Science Institute (ELSI) in Tokyo and the other with NASA’s Nexus for Exoplanet System Science (NExSS.) What they have to say is most interesting.

    This is what Shawn Domagal-Goldman, an astrobiologist at the Goddard Space Flight Center, had to say about their effort, which began 16 months ago with a workshop in Seattle:

    “This is an ‘all-hands-on-deck’ problem, and we held a workshop to start drawing a wide variety of scientists to the problem. Once we did, the group gave itself an ambitious goal – to quantify an assessment of whether or not an exoplanet has life, based on remote observations of that world.

    “Doing that will take years of collaboration of scientists like the ones at the meeting, from diverse backgrounds and diverse experiences.”

    Chaitanya Giri, a research scientist at ELSI with a background in organic planetary chemistry and organic cosmochemistry, said that his work on the European Rosetta mission to a comet convinced him that it is essential to “develop technological capacities to explore habitable niches on various planetary bodies and find unambiguous signatures of life, if present.” There is some debate about the organic molecules — the chemical building blocks of life — identified by Rosetta.

    “Over the years there have been scattered attempts at building such instruments, but a coherent collaborative network was missing,” Giri said. “This necessity inspired me to put on this workshop,” which led to the white paper.

    We’ll discuss the conclusions of the papers, but first at little about the decadal surveys:

    2
    NASA Decada:

    Here are the instruction from the NAS to potential white paper teams working on life beyond Earth projects and issues:

    Identify promising key research goals in the field of the search for signs of life in which progress is likely in the next 20 years.
    Identify key technological challenges in astrobiology as they pertain to the search for life in the solar system and extrasolar planetary systems.
    Identify key scientific questions in astrobiology as they pertain to the search for life in the solar system and extrasolar planetary systems
    Discuss scientific advances that can be addressed by U.S. and international space missions and relevant ground-based activities in operation or funded and in development
    Discuss how to expand partnerships (interagency, international and public/private) in furthering the study of life’s origin, evolution, distribution, and future in the universe

    Quite a wide net, from specific issues to much broader ones. But the teams submitting their papers are not expected to address all the issues, but only one or perhaps a related second.
    The papers range from a SETI Institute call for a program to increase the use of artificial intelligence and machine learning to address a range of astrobiology issues; to tempting possibilities offered by teams already in the running for future missions to Europa or Enceladus or elsewhere; to recommendations from the Planetary Science Institute about studying and searching for microbialites, living carbonate rock structures once common on Earth and possibly on Mars as well.

    Proposed White Paper Subjects

    3
    Several white papers discussed the desirability of sending a proble to Saturn’s moon Enceladus. plume of water vapor flowing out from its South Pole. (NASA)

    4
    Microbialites are fresh water versions of the organic and carbonate structures called stromatolites — which are among the oldest signs of life detected on Earth.

    The white paper from ELSI focuses how to improve and discover technology that can detect potential life on other planets and moons. It calls for an increasingly international approach to that costly and specialized effort.

    The paper from Giri et al begins with a disquieting conclusion that only “lately,
    scattered efforts are being undertaken towards the R&D of the novel and as-yet space unproven
    ‘life-detection’ technologies capable of obtaining unambiguous evidence of
    extraterrestrial life, even if it is significantly different from {Earth} life. As the suite of
    space-proven payloads improves in breadth and sensitivity, this is an apt time to examine the
    progress and future of life-detection technologies.”
    The paper points to one discovery in particular as indicative of what the team feels is necessary — an ability to search for life in regions theoretically devoid of life and therefore requiring novel detection
    techniques or probes.
    “For example,” they write, “air sampling in Earth’s stratosphere with a novel
    scientific cryogenic payload has led to the isolation and identification of several new species
    of bacteria; this was an innovative technique analyzing a region of the atmosphere that was
    initially believed to be devoid of life.”
    Other technologies they see as promising and needing further development are high-sensitivity fluorescence microscopy techniques that may be able to detect extraterrestrial organic compounds with catalytic activity surrounded by membranes, i.e., extraterrestrial cells. In addition, they support on-going and NASA-funded work on genetic samplers that could go to Mars and — if present — actually identify nucleic acid-based life.
    “With back-to-back missions under development and proposed by various space agencies to the potentially habitable Mars, Enceladus, Titan, and Europa, this is a right time for a detailed envisioning of the technologies needed for detection of life,” Giri said in an e-mail.

    5
    Yellowknife Bay on Mars, where the rover Curiosity first found conditions that were habitable to life. The rover subsequently found many more habitable spots, but no existing or fossil life so far. (NASA)

    The NExSS white paper is an especially ambitious one, and focuses on potential biosignatures from distant exoplanets. The NASA-sponsored effort brought in many top scientists working in the field of biosignatures, and in the past year has already resulted in the publication or submission of five major science papers in addition to the white paper.
    In keeping with the interdisciplinary mission of NExSS, the paper brought in people from many fields and ultimately advocates for a Bayesian approach to exoplanet life detection (named after 18th century statistician and philosopher Thomas Bayes. )
    In most basic terms, the Bayes approach describes the probability of an event based on prior knowledge of conditions that might be related to the event. A simple example: Runners A and B have competed four times, and runner A won three times. So the probability of A winner is high, right? But what if the two competed twice on a rainy track and each won one race. If the forecast for the day of the next race is rain, the probability of who will be the winner would change.
    This approach not only embraces probability as an essential way forward, but it is especially useful in terms of weighing probabilities involving many measurements and fields. Because the factors involved in finding a biosignature are so complex and potentially confounding, they argue, the field has to think in terms of the probability that a number of biosignatures together suggest the presence of life, rather than a 100 percent certain detection (although that may some day be possible.)
    Both Domagal-Goldman and collaborator exoplanet photosynthesis expert Nancy Kiang of NASA’s Goddard Institute for Space Studies are eager to adopt climate modeling and it’s ability to use known characteristics of divergent sub-fields to put together a big picture.
    For instance, Kiang said, the Global Climate Modeling program at GISS simulates the circulation patterns of Earth’s wind, heat, moisture, and gases, and can make pretty good predictions of what climate conditions will result. She sees a similar possibility with exoplanets and biosignatures.
    Such a computer model can take in data from different fields and come up with some probabilities. The model “might tell us that a planet is habitable over a certain percent of its surface,” she said.
    “A geochemist or planetary formation person might then tell us that if certain chemistry exists on that planet, it has good potential for prebiotic compounds to form. A biologist and geologist might tell us that certain surface signatures on the planet are plausible for either life or mineral background.” That’s not a robust biosignature, but the probability that it could be life is not zero, depending on origin of the signature.
    “These different forms of information can be integrated into a Bayesian analysis to tell us the likelihood of life on the planet,” she wrote.
    One arm of the NExSS team is already using the tools of climate modeling to predict how particular conditions on exoplanets would play out under different circumstances.

    6
    This example of how Earth planet modeling can be used for exoplanets is a plot of what the sea ice distribution could look like on a synchronously rotating ocean world. The star is off to the right, blue is where there is open ocean, and white is where there is sea ice. (NASA/GISS/Anthony Del Genio)

    I will return to the NExSS biosignatures white paper later, since it is so rich with cutting edge thinking about this upcoming stage in space science. But I do want to include one specific recommendation made by what is called the Exoplanet Biosignatures Workshop Without Walls (EBWWW).
    What they say is necessary now is for more biologists to join the search for extraterrestrial life.
    “The EBWWW revealed that the search for exoplanet life is still largely driven by astronomers
    and planetary scientists, and that this field requires more input from origins of life researchers
    and biologists to advance a process-based understanding for planetary biosignatures.
    “This includes assessing the {already assessed probability} that a planet may have life, or a life process evolved for a given planet’s environment. These advances will require fundamental research into the origins and processes of life, in particular for environments that vary from modern Earth’s. Thus, collaboration between origins of life researchers, biologists, and planetary scientists is critical to defining research questions around environmental context.”
    The recommendation, it seems to me, illustrates both the infancy and the maturing of the field.

    See the full article here .

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    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
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