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  • richardmitnick 10:09 am on May 22, 2017 Permalink | Reply
    Tags: , , , , , Getting Real About the Oxygen Biosignature, Many Worlds   

    From Many Worlds: “Getting Real About the Oxygen Biosignature” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-05-22
    Marc Kaufman

    1
    Oxygen, which makes up about 21 percent of the Earth atmosphere, has been embraced as the best biosignature for life on faraway exoplanets. New research shows that detecting distant life via the oxygen biosignature is not so straight-forward, though it probably remains the best show we have. (NASA)

    I remember the first time I heard about the atmospheres of distant exoplanets and how could and would let us know whether life was present below.

    The key was oxygen or its light-modified form, ozone. Because both oxygen and ozone molecules bond so quickly with other molecules — think rust or iron oxide on Mars, silicon dioxide in the Earth’s crust — it was said that oxygen could only be present in large and detectable quantities if there was a steady and massive source of free oxygen on the planet.

    On Earth, this of course is the work of photosynthesizers such as planets, algae and cyanobacteria, which produce oxygen as a byproduct.

    2
    An image of Cyanobacteria, Tolypothrix.
    Date 22 January 2013
    Author Matthewjparker

    No other abiotic, or non-biological, ways were known at the time to produce substantial amounts of atmospheric oxygen, so it seemed that an oxygen signal from afar would be a pretty sure sign of life.

    But with the fast growth of the field of exoplanet atmospheres and the very real possibility of having technology available in the years ahead that could measure the components of those atmospheres, scientists have been busy modelling exoplanet formations, chemistry and their atmospheres.

    One important goal has been to search for non-biological ways to produce large enough amounts of atmospheric oxygen that might fool us into thinking that life has been found below.

    And in recent years, scientists have succeeded in poking holes in the atmospheric oxygen-means-life scenario.

    3
    Oxygen bonds quickly with many other molecules. That means has to be resupplied regularly to be present as O2 in an atmosphere . On Earth, O2 is mostly a product of biology, but elsewhere it might be result of non-biological processes. Here is an image of oxygen bubbles in water.

    Especially researchers at the University of Washington’s Virtual Planetary Laboratory (VPL) have come up with numerous ways that exoplanets atmospheres can be filled (and constantly refilled) with oxygen that was never part of plant or algal or bacteria photo-chemistry.

    In other words, they found potential false positives for atmospheric oxygen as a biosignature, to the dismay of many exoplanet scientists.

    In part because she and her own team were involved in some of these oxygen false-positive papers, VPL director Victoria Meadows set out to review, analyze and come to some conclusions about what had become the oxygen-biosignature problem.

    The lengthy paper (originally planned for 6 pages but ultimately 34 pages because research from so many disciplines was coming in) was published last month in the journal Astrobiology. It seeks to both warn researchers about the possibilities of biosignature false-positives based on oxygen detection, and then it assures them that there are ways around the obstacles.

    “There was this view in the community that oxygen could only be formed by photosynthesis, and that no other process could make O2,” Meadows told me. “It was a little simplistic. We now see the rich complexity of what we are looking at, and are thinking about the evolutionary paths of these planets.

    4
    Artist’s impression of the exoplanet GJ 1132 b, which orbits the red dwarf star GJ 1132. Earlier this year, astronomers managed to detect the atmosphere of this Earth-sized planet and have determined that water and methane are likely prevalent in the atmosphere. (Max Planck Institute for Astronomy)

    “What I see is a maturing of the field. We have models that show plausible ways for oxygen to be produced without biology, but that doesn’t mean that oxygen is no longer an important biosignature.

    “It is very important. But it has to be seen and understood in the larger context of what else is happening on the planet and its host star.”

    Before moving forward, perhaps we should look back a bit at the history of oxygen on Earth.

    For substantial parts of our planet’s history there was only minimal oxygen in the atmosphere, and life survived in an anaerobic environment. When exactly oxygen went from a small percentage of the atmosphere to 21 percent of the atmosphere is contested, but there is broader agreement about the source of the O2 in the atmosphere. The source was photosynthesis, most importantly coming from cyanobacteria in the oceans.

    As far back as four billion years ago, photosynthesis occurred on Earth based on the capturing of the energy of near infrared light by sulfur-rich organisms, but it did not involve the release of oxygen as a byproduct.

    5
    A chart showing the percentage rise in oxygen in Earth’s atmosphere over the past 3.8 billion years. The great oxidation event occurred some 2.3 billion years ago, but it took more than a billion additional years for the build-up to have much effect on the composition of the planet’s atmosphere.

    Then came the the rise of cyanobacteria in the ocean and their production of oxygen. With their significantly expanded ability to use photosynthesis, this bacterium was able to generate up to 16 times more energy than its counterparts, which allowed it to out-compete and explode in reproduction.

    It took hundreds of millions of years more, but that steady increase in the cyanobacteria population led to what is called the “Great Oxidation Event” of some 2.3 billion years ago, when oxygen levels began to really climb in Earth’s atmosphere. They did level off and remained well below current levels for another billion years, but then shot up in the past billion years.

    As Meadows (and others) point out, this means that life existed on Earth for at least two billion years years without producing a detectable oxygen biosignature. It’s perhaps the ultimate false negative.

    But as biosignatures go, oxygen offers a lot. Because it bonds so readily with other elements and compounds, it remains unbonded or “free” O2 only if it is being constantly produced. On Earth, the mode of production is overwhelmingly photosynthesis and biology. What’s more, phototrophs — organism that manufacture their own food from inorganic substances using light for energy — often produce reflections and seasonally dependent biosignatures that can serve as secondary confirmations of biology as the source for abundant O2 in an atmosphere.

    So in a general way, it makes perfect sense to think that O2 in the atmosphere of an exoplanet would signify the presence of photosynthesis and life.

    The problem arises because other worlds out there orbiting stars very different than our own can have quite different chemical and physical dynamics and evolutionary histories, with results at odds with our world.

    For instance, when it comes to the non-biological production of substantial amounts of oxygen that could collect in the atmosphere, the dynamics involved could include the following:

    Perhaps the trickiest false positive involves the possible non-biological release of O2 via the photolysis of water — the breaking apart of H2O molecules by light. On Earth, the water vapor in the atmosphere condenses into liquids after reaching a certain height and related temperature, and ultimately falls back down to the surface. How and why that happens is related to the presence of large amounts of nitrogen in our atmosphere.

    But what if an exoplanet atmosphere doesn’t have a lot of an element like nitrogen that allows the water to condense? Then the water would rise into the stratosphere, where it would be subject to intense UV light,. The molecule would be split, and an H atom would fly off into space — leaving behind large amounts of oxygen that had nothing to do with life. This conclusion was reached by Robin Wordsworth and Raymond Pierrehumbert of the University of Chicago and was published by the The Astrophysical Journal.

    Another recently proposed mechanism to generate high levels of abiotic oxygen, first described by Rodrigo Luger and Rory Barnes of Meadow’s VPL team, focuses on the effects of the super-luminous phase of young stars on any rocky planets that might be orbiting them.

    Small-mass M dwarfs in particular can burn much brighter when they are young, exposing potential planets around those stars to very high levels of radiation for as long as one billion years.

    Modeling suggests that during this super-luminous phase a terrestrial planet that forms within what will become the main sequence habitable zone around an M dwarf star may lose up to several Earth ocean equivalents of water due to evaporation and hydrodynamic escape, and this can lead to generation of large amounts of abiotic O2 via the same H2O photolysis process.

    Non-biological oxygen can also build up on an exoplanet, according to a number of researchers, if the host star sends out a higher proportion of far ultraviolet light than near ultraviolet. The dynamics of photo-chemistry are such, they argue, that the excess far ultraviolet radiation would split CO2 to an extent that O2 would build up in the atmosphere.

    There are other potential scenarios that would produce an oxygen false positive, and almost all of them involve radiation from the host star driving chemistry in the planet’s atmosphere, with the planetary environment then allowing O2 to build up. While some of these false positive mechanisms can produce enough oxygen to make a big impact on their planets, some may not produce enough to even be seen by telescopes currently being planned.

    As Meadows tells it, it was Shawn Domagal-Goldman of NASA Goddard and VPL who first brought the issue of oxygen false-positives to her attention. It was back in 2010 after he found an anomaly in his photo-chemical code results regarding atmospheric oxygen and exoplanets, and followed it. Since that initial finding, several other VPL researchers discovered new ways to produce O2 without life, and often while undertaking research focused on a different scientific goal.

    Six years later, when she was writing up a VPL annual report, it jumped out that the group (and others) had found quite a few potential oxygen false positives — a significant development in the field of biosignature detection and interpretation. That’s when she decided that an analysis and summary of the findings would be useful and important for the exoplanet community. “Never let it be said that administrative tasks can’t lead to inspiration!” she wrote to me.

    While Meadows does not downplay the new challenges to defining oxygen and ozone as credible biosignatures, she does say that these new understandings can be worked around.

    Some of that involves targeting planets and stars for observation that don’t have the characteristics known to produce abiotic oxygen. Some involves finding signatures of this abiotic oxygen that can be identified and then used to discard potential false positives. And perhaps most telling, the detection of methane alongside free oxygen in an exoplanet atmosphere would be considered a powerful signature of life.

    The official goal of Meadows’ VPL is to wrestle with this question: “How would we determine if an extrasolar planet were able to support life or had life on it already?”

    This has led her to a highly interdisciplinary approach, bringing together fifty researchers from twenty institutions. In addition to its leading role in the NASA Astrobiology Institute, the VPL is also part of a broad NASA initiative to bring together scientists from different locales and disciplines to work on issues and problems of exoplanet research — the Nexus for Exoplanet System Science, or NExSS.

    Given this background and these approaches, it is hardly surprising that Meadows would be among the first to see the oxygen-false positive issue in both scientific and collective terms.

    “I wanted the community to have some place to go to when thinking about O2 false positives,” she said. “We’re learning now about the complexity and richness of exoplanets, and this is essential for preparing to do the best job possible {in terms of looking for signs of life on exoplanets} when we get better and better observations to work with.”

    “This story needed to be told now. Forewarned is forearmed.”

    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.

     
  • richardmitnick 11:22 am on May 15, 2017 Permalink | Reply
    Tags: , , , , , Many Worlds, , Planetary Protection is a “Wicked” Problem   

    From Many Worlds: “Planetary Protection is a “Wicked” Problem” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-05-15
    Marc Kaufman
    marc.kaufman@manyworlds.space

    1
    The Viking landers were baked for 30 hours after assembly, a dry heat sterilization that is considered the gold standard for planetary protection.

    NASA/Viking 1 Lander

    Before the baking, the landers were given a preliminary cleaning to reduce the number of potential microbial spores. The levels achieved with that preliminary cleaning are similar to what is now required for a mission to Mars unless the destination is an area known to be suitable for Martian life. In that case, a sterilizing equivalent to the Viking baking is required. (NASA)

    The only time that a formally designated NASA “life detection” mission was flown to another planet or moon was when the two Viking landers headed to Mars forty years ago.

    The odds of finding some kind of Martian life seemed so promising at the time that there was little dispute about how much energy, money and care should be allocated to making sure the capsule would not be carrying any Earth life to the planet. And so after the two landers had been assembled, they were baked at more than 250 °F for three days to sterilize any parts that would come into contact with Mars.

    Although the two landers successfully touched down on the Martian surface and did some impressive science, the life detection portion of the mission was something of a fiasco — with conflict, controversy and ultimately quite a bit of confusion.

    Clearly, scientists did not yet know enough about how to search for life beyond Earth and the confounding results pretty much eliminated life-detection from NASA’s missions for decades.

    But scientific and technological advances of the last ten years have put life detection squarely back on the agenda — in terms of future searches for fossil biosignatures on Mars and for potential life surviving in the oceans of Europa and Enceladus. What’s more, both NASA and private space companies talk seriously of sending humans to Mars in the not-too-distant future.

    With so many missions being planned, developed and proposed for solar system planets and moons, the issue of planetary protection has also gained a higher profile. It seems to have become more contentious and to some seems far less straight-forward as it used to be.

    A broad consensus appears to remain that bringing Earth life to another planet or moon, especially if it is potentially habitable, is a real possibility that is both scientifically and ethically fraught. But there are rumblings about just how much time, money and attention needs to be brought to satisfying the requirements of “planetary protection.”

    In fact, it has become a sufficiently significant question that the first plenary session of the recent Astrobiology Science Conference in Mesa, Arizona was dedicated to it. The issue, which was taken up in later technical sessions as well, was how to assess and weigh the risks of bringing Earth life to other bodies versus the benefits of potentially sending out more missions, more often and more cheaply.

    It is not a simple problem, explained Andrew Maynard, director of the Risk Innovation Lab at Arizona State University. Indeed, he told the audience of scientists that it was a “wicked problem,” a broadly used terms for issues that are especially complex and involve numerous issues and players.

    2
    A primary barrier to keeping microbes off spacecraft and instruments going to space is to build them in clean rooms, such as this one at JPL. These large rooms with filtered air do help lower the count of microbes on surfaces, but the bacteria are everywhere and further steps are essential. (NASA/JPL-Caltech)

    As he later elaborated to me, other “wicked” risk-benefit problems include gene editing and autonomous driving — both filled with great potential and serious potential downsides. Like travel to other planets and moons.

    “This is subjective,” Maynard said, “but I’d put planetary protection on the more wicked end of the spectrum. It combines individual priorities and ethics — what people and groups deeply believe is right — with huge uncertainties. That makes it something never really experienced before and so escalates all factors of wickedness.”

    Those groups include scientists (who very much don’t want Mars or another potentially habitable place to be contaminated with Earth life before they can get there), to advocates of greater space exploration (who worry that planetary protection will slow or eliminate some missions they very much want to proceed), to NASA mission managers (worried about delays and costs associated with planetary protections surprises.)

    And then there’s the general public which might (or might not) have entirely different ethical concerns about the potential for contaminating other planets and moons with Earth life.

    No wonder the problem is deemed wicked.

    We’ll get into the pros and cons, but first some background:

    I asked NASA’s Planetary Protection officer, Catharine Conley, whether Earth life has been transported to its most likely solar system destination, Mars.

    3
    Catharine “Cassie” Conley has been NASA’s Planetary Protection officer since 2006. There is only one other full-time official in the world with the same responsibilities, and he works for the European Space Agency. (NASA/W. Hrybyk)

    Her reply: “There are definitely Earth organisms that we’ve brought to Mars and are still alive on the spacecraft.”

    NASA/Mars Curiosity Rover

    She said it is quite possible that some of those organisms were brushed off the vehicles or otherwise were shed and fell to the surface. Because of the strong ultraviolet radiation and the Earth life-destroying chemical makeup of the soil, however, it’s unlikely the organisms could last for long, and equally unlikely that any would have made it below the surface. Nonetheless, it is sobering to hear that Earth life has already made it to Mars.

    Related to this reality is the understanding that Earth life, in the form of bacteria, algae and fungi and their spores, can be extraordinarily resilient. Organisms have been discovered that can survive unimagined extremes of heat and cold, can withstand radiation that would kill us, and can survive as dormant spores for tens of thousands of years.

    What’s more, Mars scientists now know that the planet was once much warmer and wetter, and that ice underlies substantial portions of the planet. There are even signs today of seasonal runs of what some scientists argue is very briny surface water.

    So the risk of Earth life surviving a ride to another planet or moon is probably greater than imagined earlier, and the possibility of that Earth life potentially surviving and spreading on a distant surface (think the oceans of Europa and Enceladus, or maybe a briny, moist hideaway on Mars) is arguably greater too. From a planetary protection perspective, all of this is worrisome.

    The logic of planetary protection is, like almost everything involved with the subject, based on probabilities. Discussed as far back as the 1950s and formalized in the 1967 Outer Space Treaty, the standard agreed on is to take steps that ensure there is less than a 1 in 10,000 chance of a spaceship or lander or instrument from Earth bringing life to another body.

    This figure takes into account the number of microorganisms on the spacecraft, the probability of growth on the planet or moon where the mission is headed, and a series of potential sanitizing to sterilizing procedures that can be used. A formula for assessing the risk of a mission for planetary protection purposes was worked out in 1965 by Carl Sagan, along with Harvard theoretical physicist Sidney Coleman.

    4
    Deinococcus radiodurans is an extremophilic bacterium, one of the most radiation-resistant organisms known. It can survive cold, dehydration, vacuum, and acid, and is therefore known as a polyextremophile and is considered perhaps the world’s toughest bacterium. It can withstand a radiation dose 1,000 times stronger than what would kill a person. No image credit.

    A lot has been learned since that time, and some in the field say it’s time to re-address the basics of planetary protection. They argue, for instance, that since we now know that Earth life can (theoretically, at least) be carried inside a meteorite from our planet to Mars, then Earth life may have long been on Mars — if it is robust enough to survive when it lands.

    In addition, a great deal more is known about how to sanitize a space vehicle without baking it entirely — a step that is both very costly and could prove deadly to the more sophisticated capsules and instruments. And more is known about the punishing environment on the surface of Mars and elsewhere.

    People ranging from Mars Society founder Robert Zubrin to Cornell University Visiting Scientist Alberto G. Fairén in Nature Geoscience have argued — and sometimes railed — against planetary protection requirements. NASA mission managers have often voiced their concerns as well. The regulations, some say, slow the pace of exploration and science to avoid a vanishingly small risk.

    5
    Brent Sherwood, planetary mission formulation manager for JPL, is currently overseeing two proposed projects for New Frontiers missions. One is to search for signs of life on Saturn’s moon Enceladus and the other for habitability on the moon Titan. (Brent Sherwood)

    Brent Sherwood, program manager for solar system mission formulation at JPL, spoke at AbSciCon about what he sees as the need for a review and possibly reassessment of the planetary protection rules and regulations. As someone who helps scientists put together proposals for NASA missions in the solar system, he has practical and long considered views about planetary protection.

    He and his co-authors argue that the broad conversation that needs to take place should include scientists, ethicists, managers, and policy makers; and especially should include the generations that will actually implement and live with the consequences of these missions.

    In the abstract for his talk, Sherwood wrote:

    “The (1 chance in 10,000) requirement may not be as logically sound or deserving of perpetuation as generally assumed. What status should this requirement have within an ethical decision-making process? Do we need a meta-ethical discussion about absolute values, rather than an arbitrary number that purports to govern the absolute necessity of preserving scientific discovery or protecting alien life?”
    As he later he told me: “I’m recommending that we be proactive and engage the broadest possible range of stakeholder communities…. With these big, hairy risk problems, everything is probabilistic and open to argument. People are bad at thinking of very small and very big numbers, and the same for risks. They tend to substitute opinion for fact.”
    Sherwood is no foe of planetary protection. But he said planetary protection is a “foundational” part of the space program, and he wants to make sure it is properly adapted for the new space era we are entering.”

    6
    Elon Musk of SpaceX, Jeff Bezos of Blue Origins and NASA have all talked about potentially sending astronauts to Mars or establishing a colony on Mars in the decades ahead. Many obstacles remain, but planning is underway. (Bryan Versteeg/Spacehabs.com)

    Planetary protection officer Conley contends that regular reviews are already built into the system. She told me that every mission gets a thorough planetary protection assessment early in the process, and that there is no one-size-fits-all approach. Rather, the risks and architecture of the missions are studied within the context of the prevailing rules.

    In addition, she said, the group that oversees planetary protection internationally — the Committee on Space Research (COSPAR) — meets every two years and its Panel on Planetary Protection takes up general topics and welcomes input from whomever might want to raise issues large or small.

    “You hear it said that there are protected areas on Mars or Europa where missions can’t go, but that’s not the case,” she said. “These are sensitive areas where life just might be present now or was present in the past. If that’s the case, then the capsule or lander or rover has to be sterilized to the level of the Viking missions.”

    She said that she understood that today’s spacecraft are different from Viking, which was designed and built from scratch with planetary protection in mind. Today, JPL and other mission builders get some of their parts “off the shelf” in an effort to make space exploration less expensive.

    “We do have to balance the goals of exploration and space science with making sure that Earth life does not take hold. We also have to be aware that taxpayer money is being spent. But if a mission sent out returns a signal of life, what have we achieved if it turns out to be life we brought there?

    “I see planetary protection as a great success story. People identified a potential contamination problem back in the 50s, put regulations into place, and have succeeded in avoiding the problem. This kind of global cooperation that leads to the preventing of a potentially major problem just doesn’t happen that often.

    The global cooperation has been robust, Conley said, despite the fact that only NASA and the European Space Agency have a full-time planetary protection officer.

    She cited the planning for the joint Russian-Chinese mission to the Martian moon Phobos as an example of other nations agreeing to very high standards. She and her European Space Agency (ESA) counterpart traveled twice to Moscow to discuss planetary protection steps being taken.

    7
    Andrew Maynard is the director of Arizona State University’s Risk Innovation Lab and is a professor in School for the Future of Innovation in Society. (ASU.)

    So far, she said private space companies have been attentive to planetary protection as well. Some of the commercial space activity in the future involve efforts to mine on asteroids, and Conley said there is no planetary protection issues involved. The same with mining on our moon.

    But should the day arrive that private companies such as SpaceX and Blue Origin seriously propose a human mission to Mars — as they have said they plan to — Conley said they would have the same obligations as for NASA mission. The US has not yet determined how to ensure that compliance, she said, but companies already would need Federal Aviation Administration approval for a launch, and planetary protection is part of that.

    Risk innovation expert Maynard, however, was not so sure about those protections. He said he could imagine a situation where Elon Musk of SpaceX or Jeff Bezos of Blue Origin or any other space entrepreneur around the world would decide to move their launch to a nation that would be willing to provide the service without intensive planetary protection oversight.

    “The risk of this may be small, but this is all about the potentially outsize consequences of small risks,” he said.

    Maynard said that was hardly a likely scenario — and that commercial space pioneers so far have been supportive of planetary protection guidelines — but that he was well aware of the displeasure among some mission managers and participating scientists about planetary protection requirements.

    Given all this, it’s easy to see how and why planetary protection advocates might feel that the floodgates are being tested, and why space explorers looking forward to a time when Mars and other bodies might be visited by astronauts and later potentially colonized are concerned about potential obstacles to their visions.

    8
    An artist’s rendering of a sample return from Mars. Both the 2020 NASA Mars mission and the ESA-Russian mission are designed to identify and cache intriguing rocks for delivery to Earth in the years ahead. (Wickman Spacecraft & Propulsion)

    This column has addressed the issue of “forward contamination” — how to prevent Earth life from being carried to another potentially habitable solar system body and surviving there. But there is another planetary protection worry and that involves “backward contamination” — how to handle the return of potentially living extraterrestrial organisms to Earth.

    That will be the subject of a later column, but suffice it to say it is very much on the global space agenda, too.

    The Apollo astronauts famously brought back pounds of moon rocks, and grains of asteroid and comet dust have also been retrieved and delivered. A sample return mission by the Russian and Chinese space agencies was designed to return rock or grain samples from the Martian moon Phobos earlier this decade, but the spacecraft did not make it beyond low Earth orbit.

    However, the future will see many more sample return attempts. The Japanese space agency JAXA launched a mission to the asteroid 162173 Ryugu in 2014 (Hayabusa 2) and it will arrive there next year.

    JAXA/Hayabusa 2

    The plan is collect rock and dust samples and bring them back to Earth. NASA’s OSIRIS-REx is also making its way to an asteroid, 101955 Bennu, with the goal of collecting a sample as well for return to Earth.

    NASA OSIRIS-REx Spacecraft

    And in 2020 both NASA and ESA (with Russian collaboration) will launch spacecraft for Mars with the intention of preparing for future sample returns. Sample return is a very high priority in the Mars and space science communities, and many consider it essential for determining whether there has ever been life on Mars.

    So the “wicked” challenges of planetary protection are only going to mount in the years ahead.

    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 4:08 pm on May 8, 2017 Permalink | Reply
    Tags: , , , , Many Worlds, , ,   

    From Many Worlds: “Supernovae Give, And Can Take Away” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-05-08
    Marc Kaufman

    1
    What is likely the brightest supernova in recorded human history, SN 1006 lit up planet Earth’s sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, still puts on a cosmic light show across the electromagnetic spectrum. The supernova is located about 7,000 light-years from Earth, meaning that its thermonuclear explosion actually happened 7,000 years before the Earth. Shockwaves in the remnant accelerate particles to extreme energies and are thought to be a source of the mysterious cosmic rays. NASA, ESA, Zolt Levay (STScI)

    We live in a dangerous universe. We know about meteor and comets, about harmful radiation that could extinguish life without an electromagnetic shield, about major changes in climate that are both natural and man-made.

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

    There’s another risk out there that some scientists assert could cause large-scale extinctions even though it would occur scores of light-years away. These are supernovae – explosions of massive stars that both create and spread the heavy elements needed for life and send out high energy cosmic rays that can travel far and cause enormous damage.

    6
    http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/snovcn.html

    As with most of these potential threats, they fortunately occur on geological or astronomical time scales rather than human ones. But that doesn’t mean they don’t happen.

    At the recent Astrobiology Science Conference (AbSciCon) a series of talks focused on that last threat – starting with a talk on “When Stars Attack.”

    And together five different presenters made a persuasive case that Earth was on the receiving end of a distant supernova explosion some two to three million years ago, and probably around 7 or 8 million years ago as well. The effects of the cosmic ray bombardment have been debated and disputed, but the evidence for the occurrences is based on the rock record and is now strong.

    “The evidence is there on the ocean floor, in rocks, nodules and sediment,” said Brian Fields, professor of astronomy at University of Illinois. “We’ve been able to date it and provide some idea of how far away the star blew up.” The answer is between about 90 and 300 light-years.

    2
    Supernova 1994D exploded on the outskirts of disk galaxy, and outshines even the center of the galaxy. Supernovae may expel much, if not all, of the material away from a star, at velocities up to 30,000 km/s or 10% of the speed of light. This drives an expanding and fast-moving shock wave into the surrounding interstellar medium that, if close to Earth (or any other planet) can have dire consequences. Supernovae also create, fuse and eject the bulk of the chemical elements produced by nucleosynthesis, the heavier elements needed to form planets and later make possible life. ( High-Z Supernova Search Team, HST, NASA)

    “Supernova explosions happen all the time– on average every 30 years in our galaxy, though they are most often obscured from view,” Fields said. “They generate cosmic rays that can spread through the galaxy for 100 million years. These are the cosmic rays that make carbon-14 and can threaten astronauts in space. But that’s not what we’re focused on — we look at the ones that are close to us and could have a far more dramatic effect, and they are pretty rare.”

    HESS Cherenko Array, searching for cosmic rays, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg

    What is deemed to be the “kill zone” for a planet nearby a supernova is 30 light-years; the high energy particles from an explosion that close would, he said, likely end all or most life on Earth by setting into motion a variety of atmospheric and surface changes. Fields there is no evidence of such a close and damaging supernove within the past 10 million years, the period that has been studied with some rigor.

    But because a close supernova explosion hasn’t happened recently doesn’t mean that it didn’t happened during earlier times. Or that it couldn’t happen in the far future.

    “By nailing the signal of a close but not ‘kill zone’ supernova two to three million years ago, and most likely another at 7 to 8 million years ago, we make the case that supernova can and do have significant effects on Earth.”

    The community of scientists who study supernovae and their effects on Earth, both potential and known, is small, and has been most active in the past decade. There was an earlier time when scientists focused on supernovae as the potential cause for the massive dinosaur extinction, but the field shrank with confirmation in 1990 that a six-mile wide meteor landed on Mexico’s Yucatan Peninsula about million years ago and was the likely cause of the global extinction.

    But now, with the advent of new theories and some very high tech and precise measuring the field and subject has come to life, with research nodes in Germany, Australia and the American Midwest.

    The key to understanding the effects of distant supernovae on Earth involves a radioactive isotope of iron, iron-60.

    7
    Nailing the half-life of iron-60, http://physicsworld.com/cws/article/news/2015/jan/30/nailing-the-half-life-of-iron-60

    It’s one of the many elements known to be sent into the cosmos by the massive thermonuclear blasts that define a supernova, that send out shock waves capable of spurring the formation of new stars as well as providing the universe with the heavier chemical elements needed to form everything from planets to genes.

    It was the young Fields and colleagues who theorized some two decades ago that iron-60 could be a telltale sign of a relatively nearby supernova. He told me that no other sources of iron 60 are known to exist, and so if it were found on Earth scientists would know where it came from.

    With a half-life of some three million years, the iron-60 would be a potentially strong signal for that length of time and and then a weaker but potentially detectable signal after that.

    The question was how do you find iron-60 on Earth? The answer came from the bottom of the ocean.

    First in 1999 a group from the Technical University of Munich [TUM] in Germany identified some iron-60 in iron-manganese crustal rocks at the bottom of the Pacific, and then last year an overlapping group from the Technical University of Berlin reported finding the telltale isotope in not only rocks but also in nodules and most important in sea-floor sediments. They used ultra-sensitive accelerator mass spectrometry to isolate and identify the iron-60, which they reported was deposited some 1.6 to 3 million years ago.

    9
    Accelerator mass spectrometer at Lawrence Livermore National Laboratory
    “The 1 MV accelerator mass spectrometer was (see photo) developed partially under the Resource funding. 14C and tritium analyses of biomedical samples submitted by Resource users are conducted using this 1 MV system. The AMS spectrometer consists of a cesium sputter source, low-energy injection beam line, the high voltage collision cell (accelerator), a high-energy mass spectrometer and a particle detector for energy measurements (proceeding clockwise from lower left in the photograph).”
    Source http://bioams.llnl.gov/equipment.php

    3
    These are transmission electron microscope images showing tiny magnetofossils containing iron-60, a form of iron produced during the violent explosion and death of a massive star in a supernova. They were deposited by bacteria in sediments found on the floor of the Pacific Ocean.© Marianne Hanzlik, Chemie Department, FG Elektronenmikroskopie, Technische Universität München

    Last year as well the Australian group, led by Anton Wallner of the Australian National University, found the iron-60 to be deposited globally and to have arrived within the same general time frame. And Gunther Korschinek, a physicist at the Technical University of Munich involved in the initial German iron-60 detections, led a team that found elevated amounts of iron-60 in moon rocks returned to Earth during the Apollo program.

    As Fields put it, the studies together gave a clear signal of a supernova explosion, or series of explosions, at 2 to 3 million years ago, and a less clear but likely signal of the same at 7 to 8 million years ago.

    Since Fields and other scientists were presenting during the AbSciCon conference, the talks not surprisingly focused on potential biological implications of supernova explosions. And while supernova impacts on the biosphere are not particularly well understood, a number of intriguing theories were presented.

    Brian Thomas of Washburn University described how cosmic rays from close supernova would significantly increase levels of electrically charged elements and molecules in the atmosphere, lasting thousands of years. In the upper atmosphere this would have the effect of setting into motion a chemical cascade that would deplete stratospheric ozone. In the lower atmosphere, the effect would likely be changes in climate and minor mass extinctions.

    The “holy grail” of their supernova work is matching a detected one with a dramatic event in the Earth biosphere, most especially a mass extinction. The 2 to 3 million years ago period includes the boundary between the Pleistocene and Pliocene epochs, when Earth climate changed and major glaciations periods began — possibly supernova-related changes but not the extreme change a close supernova could produce.

    Another potential effect of the supernova event of 2 to 3 million years ago is increased rates of mutation and of lightning, and thus forest fires on Earth.

    Adrian Merlott of the University of Kansas suggested that expected mutations from radiation sources such as supernovae could explain evolutionary changes in a variety of groups of organisms and creatures during that period — as a result of increased deadly cancers in some species and increased positive mutations in others.

    He also said that evidence of more widespread wildfires during that long period — as measured in charcoal deposits — could be the result of increased cloud to ground lightning induced by the additional high-energy particle environment created by a relatively close supernova explosion.

    4
    The Crab nebula – one of the most glorious images produced by the Hubble Space Telescope — is the remnant of supernovae explosions that occurred at a distance of some 6,700 light-years. The very bright light of the explosion was noted in 1054 and remained visible for around two years. The event was recorded in contemporary Chinese astronomy, and references to it are also found in a later (13th-century) Japanese document, perhaps in pictograph associated with the Anasazi people of the Southwest. The supernova, SN 1054 has been widely studied and is often considered the best known supernova in astronomy. (NASA).

    The iron-60 signatures of a close supernova have been a great boon to the field, but they do not go back beyond that almost 10 million year period when the radioactivity was present. To go back further than that, Fields said different radioactive signatures would be needed — and not those that go back to the formation of the planet.

    “It’s a hard problem because nature has been unkind,” he said. “The early mass extinctions – 100 million and more years ago – need radioactivity that lasts that long. And the only element we’ve found is plutonium-244, which is not stable in any form.”

    9
    http://www.alamy.com/stock-photo/plutonium-244.html

    Plutonium-244 has a half life of 80 million years, and so could potentially be used to identify close supernova explosions in a manner similar to iron-60, but during that much longer time frame. And as Fields explained it, plutonium-244 is produced in only two ways: during the explosion of a nuclear bomb or the explosion of a supernovae.

    Although the science around the formation and detection of plutonium-244 in nature is immature, he said it remains the best pathway to find that “holy grail” — a known mass extinction directly associated with a close supernova explosion.

    5
    Supernovae can burn with a luminosity of ten billion suns. This show a before and after for supernova 1987A, which exploded in 1987 in the Large Magellanic Cloud (LMC), a nearby galaxy. (Australian Astronomical Observatory/ David Malin)

    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 7:21 am on April 24, 2017 Permalink | Reply
    Tags: , , , Many Worlds, , Natalie Batalha,   

    From Many Worlds: Women in STEM – “The Influential Natalie Batalha” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-04-24
    Marc Kaufman

    1
    Natalie Batalha, project scientist for the Kepler mission and a leader of NASA’s NExSS initiative on exoplanets, was just selected as one of Time Magazine’s 100 most influential people in the world. (NASA, TIME Magazine.)

    I’d like to make a slight detour and talk not about the science of exoplanets and astrobiology, but rather a particular exoplanet scientist who I’ve had the pleasure to work with.

    The scientist is Natalie Batalha, who has been lead scientist for NASA’s landmark Kepler Space Telescope mission since soon after it launched in 2009, has serves on numerous top NASA panels and boards, and who is one of the scientists who guides the direction of this Many Worlds column.

    Last week, Batalha was named by TIME Magazine as one of the 100 most influential people in the world. This is a subjective (non-scientific) calculation for sure, but it nonetheless seems credible to me and to doubtless many others.

    Batalha and the Kepler team have identified more than 2500 exoplanets in one small section of the distant sky, with several thousand more candidates awaiting confirmation. Their work has once and for all nailed the fact that there are billions and billions of exoplanets out there.

    “NASA is incredibly proud of Natalie,” said Paul Hertz, astrophysics division director at NASA headquarters, after the Time selection was announced.

    “Her leadership on the Kepler mission and the study of exoplanets is helping to shape the quest to discover habitable exoplanets and search for life beyond the solar system. It’s wonderful to see her recognized for the influence she has had on the world – and on the way we see ourselves in the universe.”

    And William Borucki, who had the initial idea for the Kepler mission and worked for decades to get it approved and then to manage it, had this to say about Batalha:

    “She has made major contributions to the Kepler Mission throughout its development and operation. Natalie’s collaborative leadership style, and expert knowledge of the population of exoplanets in the galaxy, will provide guidance for the development of successor missions that will tell us more about the habitability of the planets orbiting nearby stars.”

    1
    Batalha has led the science mission of the Kepler Space Telescope since it launched in 2009. (NASA)

    As a sign of the perceived importance of exoplanet research, two of the other TIME influential 100 are discoverers of specific new worlds. They are Guillem Anglada-Escudé (who led a team that detected a planet orbiting Proxima Centauri) and Michael Gillon (whose team identified the potentially habitable planets around the Trappist-1 system.)

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets, NASA announced on Wednesday. (NASA)

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

    But Batalha, and no doubt the other two scientists, stress that they are part of a team and that the work they do is inherently collaborative. It absolutely requires that many others also do difficult jobs well.

    For Batalha, working in that kind of environment is a natural fit with her personality and skills. Having watched her at work many times, I can attest to her ability to be a strong leader with extremely high standards, while also being a kind of force for calm and inclusiveness.

    We worked together quite a bit on the establishing and running of this column, which is part of the NASA Nexus for Exoplanet System Science (NExSS) initiative to encourage interdisciplinary thinking and collaboration in exoplanet science.

    It was NASA’s astrobiology senior scientist Mary Voytek who set up the initiative and saw fit to start this column, and it was Batalha (along with several others) who helped guide and focus it in its early days.

    I think back to her patience. I was visiting her at NASA’s Ames Research Center in Silicon Valley and talking shop — meaning stars and planets and atmospheres and the like. While I had done a lot of science reporting by that time, astronomy was not a strong point (yet.)

    So in conversation she made a reference to stars on the Hertzsprung-Russell diagram and I must have had a somewhat blank look to me. She asked if I was familiar with Hertzsprung-Russell and I had to confess that I was not.

    Not missing a beat, she then went into an explanation of what is a basic feature of astronomy, and did it without a hint of impatience. She just wanted me to know what the diagram was and what it meant, and pushed ahead with good cheer to bring me up to speed — as I’m sure she has done many other times with many people of different levels of exposure to the logic and complexities of her very complex work.

    4
    Hertzsprung–Russell diagram with 22,000 stars plotted from the Hipparcos Catalogue and 1,000 from the Gliese Catalogue of nearby stars. Stars tend to fall only into certain regions of the diagram. The most prominent is the diagonal, going from the upper-left (hot and bright) to the lower-right (cooler and less bright), called the main sequence. In the lower-left is where white dwarfs are found, and above the main sequence are the subgiants, giants and supergiants. The Sun is found on the main sequence at luminosity 1 (absolute magnitude 4.8) and B−V color index 0.66 (temperature 5780 K, spectral type G2V). Wikipedia

    (Incidently, the Hertzsprung-Russell diagram plots each star on a graph measuring the star’s brightness against its temperature or color.)

    I mention this because part of Batalha’s influence has to do with her ability to communicate with individuals and audiences from the lay to the most scientifically sophisticated. Not surprisingly, she is often invited to be a speaker and I recommend catching her at the podium if you can.

    3
    By chance — or was it chance? — the three exoplanet scientists selected for the Time 100 were at Yuri Milner’s Breakthrough Discuss session Thursday when the news came out. On the left is Anglada-Escude, Batalha in the middle and Gillon on the right.

    Batalha was born in Northern California with absolutely no intention of being a scientist. Her idea of a scientist, in fact, was a guy in a white lab coat pouring chemicals into a beaker.

    As a young woman, she was an undergrad at the University of California at Berkeley and planned on going into business. But she had always been very good and advanced in math, and so she toyed with other paths. Then, one day, astronaut Rhea Setton came to her sorority. Setton had been a member of the same sorority and came to deliver a sorority pin she had taken up with during on a flight on the Space Shuttle.

    “That visit changed my path,” Batalha told me. “When I had that opportunity to see a woman astronaut, to see that working for NASA was a possibility, I decided to switch my major — from business to physics.”

    After getting her BA in physics from UC Berkeley, she continued in the field and earned a PhD in astrophysics from UC Santa Cruz. Batalha started her career as a stellar spectroscopist studying young, sun-like stars. Her studies took her to Brazil, Chile and, in 1995, Italy, where she was present at the scientific conference when the world learned of the first planet orbiting another star like our sun — 51 Pegasi b.

    It had quite an impact. Four years later, after a discussion with Kepler principal investigator Borucki at Ames about challenges that star spots present in distinguishing signals from transiting planets, she was hired to join the Kepler team. She has been working on the Kepler mission ever since.

    Asked how she would like to use her now publicly acknowledged “influence,” she returned to her work on the search for habitable planets, and potentially life, beyond earth.

    “We’ve seen that there’s such a keen public interest and an enormous scientific interest in terms of habitable worlds, and we have to keep that going,” she said. “This is a very hard problem to solve, and we need all hands on deck.”

    She said the effort has to be interdisciplinary and international to succeed, and she pointed to the two other time 100 exoplanet hunters selected. One is from Belgium and the other is working in the United Kingdom, but comes from Spain.

    When the nominal Kepler mission formally winds down in September, she says she looks forward to more actively engaging with the exoplanet science Kepler has made possible.

    4
    The small planets identified by Kepler as of one year ago that are small and orbit in the region around their star where water can exist as a liquid. NASA Ames/N. Batalha and W. Stenzel

    Batalha’s role in the NASA NExSS initiative offers a window into what makes her a leader — she excels at making things happen.

    Voytek and Shawn Domogal-Goldman of Goddard founded and oversee the group. They then chose Batalha two other leaders (Anthony Del Genio of the Goddard Institute for Space Studies and Dawn Gelino of NASA Exoplanet Science Institute ) to be the hands-on leaders of the 18 groups of scientists from a wide variety of American universities.

    (Asked why she selected Batalha, Voytek replied, “TIME is recognizing what motivated us to select her as one of the leaders for….NExSS. Her scientific and leadership excellence.”)

    This is the official NExSS task: “Teams will help classify the diversity of worlds being discovered, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Scientists are developing ways to identify habitable environments on these worlds and search for biosignatures, or signs of life. Central to the work of NExSS is understanding how biology interacts with the atmosphere, surface, oceans, and interior of a planet, and how these interactions are affected by the host star.”

    She has encouraged and helped create the kinds of collaborations that these tasks have made essential, but also helped identify upcoming problems and opportunities for exoplanet research and has started working on ways to address them. For instance, it became clear within the NExSS group and larger community that many, if not most exoplanet researchers would not be able to effectively apply for time to use the James Webb Space Telescope (JWST) for several years after it launched in late 2018.

    NASA/ESA/CSA Webb Telescope annotated

    To be awarded time on the telescope, researchers have to write detailed descriptions of what they plan to do and how they will do it. But how the giant telescope will operate in space is not entirely know — especially as relates to exoplanets. So it will be impossible for most researchers to make proposals and win time until JWST is already in space for at least two of its five years of operation.

    Led by Batalha, exoplanet scientists are now hashing out a short list of JWST targets that the community as a whole can agree should be the top priorities scientifically and to allow researchers to learn better how JWST works. As a result, they would be able to propose their own targets for research much more quickly in those early years of JWST operations. It’s the kind of community consensus building that Batalha is known for.

    She also has an important roles in the NASA Astrophysics Advisory Committee and hopes to use the skills she developed working with Kepler on the upcoming Transiting Exoplanet Survey Satellite (TESS) mission.

    NASA/TESS

    5
    Batalha preparing for the Science Walk in San Francisco on Earth Day.

    A mother of four (including daughter Natasha, who is on her way to also becoming an accomplished astrophysicist), Batalha is active on Facebook sharing her activities, her often poetic thoughts, and her strong views about scientific and other issues of the day.

    She was an active participant, for instance, in the National March for Science in San Francisco, posting photos and impressions along the way. I think it’s fair to say her presence was noticed with appreciation by others.

    And that returns us to what she considers to be some of her greatest potential “influence” — being an accomplished, high ranking and high profile NASA female scientist.

    “I don’t have to stand up and say to young women ‘You can do this.’ You can just exist doing your work and you become a role model. Like Rhea Setton did with me.”

    And it is probably no coincidence that four other senior (and demanding) positions on the Kepler mission are filled by women — two of whom were students in classes taught some years ago by Natalie Batalha.

    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 11:23 am on April 21, 2017 Permalink | Reply
    Tags: , , , , Many Worlds,   

    From Many Worlds: “NASA Panel Supports Life-Detecting Lander for Europa; Updated” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-04-20
    Marc Kaufman

    1
    Artist conception of water vapor plumes coming from beneath the thick ice of Jupiter’s moon Europa. The plumes have not been definitively detected, but Hubble Space Telescope images made public earlier this month appear to show plume activity in an area where it was detected once before. How will this finding affect decision-making about a potential NASA Europa lander mission? (NASA)

    As I prepare for the Astrobiology Science Conference (Abscicon) next week in Arizona, I’m struck by how many speakers will be discussing Europa missions, Europa science, ocean worlds and habitability under ice. NASA’s Europa Clipper mission to orbit that moon, scheduled for launch to the Jupiter system in the mid 2020s, explains part of the interest, but so too does the unsettled fate of the Europa lander concept.

    NASA Europa Clipper

    The NASA Science Definition Team that studied the Europa lander project will both give a science talk at the conference and hold an afternoon-long science community meeting on their conclusions. The team argued that landing on Europa holds enormous scientific promise, most especially in the search for life beyond Earth.

    But since the Europa lander SDT wrote its report and took its conclusions public early this year, the landscape has changed substantially. First, in March, the Trump Administration 2018 budget eliminated funding for the lander project. More than half a billion dollars have been spent on Europa lander research and development, but the full project was considered to be too expensive by the White House.

    Administration budget proposals and what ultimately become budget reality can be quite different, and as soon as the Europa lander was cancelled supporters in Congress pushed back. Rep. John Culberson (R-Tex.) and chair of the House subcommittee that oversees the NASA budget, replied to the proposed cancellation by saying “NASA is a strategic national asset and I have no doubt NASA will receive sufficient funding to complete the most important missions identified by the science community, including seeking out life in the oceans of Europa.”

    More recently, researchers announced additional detections of plumes of water vapor apparently coming out of Europa — plumes in the same location as a previous apparent detection. The observing team said they were confident the difficult observation was indeed water vapor, but remained less than 100 percent certain. (Unlike for the detection of a water plume on Saturn’s moon Enceladeus, which the Cassini spacecraft photographed, measured and flew through.)

    So while suffering a serious blow in the budgeting process, the case for a Europa lander has gotten considerably stronger from a science and logistics perspective. Assuming that the plume detections are accurate, a lander touching down in that general area would potentially have some access to surface H20 that was in the vast global ocean under the ice not too long ago.

    Science fiction writer and proto-astrobiologist Arthur C. Clarke famously wrote decades ago that the first life found beyond Earth would most likely be in the oceans of Europa. In the early 1980s he wrote a sequel to “2001: A Space Odyssey” called “2010: Odyssey Two”, with life under the ice of Europa central to the plot.

    At the climactic moment in the novel, the hero returns to the iconic computer HAL which sends out this message:

    ALL THESE WORLDS ARE YOURS – EXCEPT EUROPA.
    ATTEMPT NO LANDINGS THERE.

    Hopefully Congress and the White House, if not HAL, can be persuaded otherwise.

    Here is a column I wrote about the Europa lander SDT in February:

    2
    Artist rendering of a potential life-detecting lander mission to Europa that would follow on the Europa Clipper orbiter mission. In the background is Jupiter. NASA/JPL/Caltech

    It has been four long decades since NASA has sent an officially-designated life detection mission into space. The confused results of the Viking missions to Mars in the mid 1970s were so controversial and contradictory that scientists — or the agency at least — concluded that the knowledge needed to convincingly search for extraterrestrial life wasn’t available yet.

    But now, a panel of scientists and engineers brought together by NASA has studied a proposal to send a lander to Jupiter’s moon Europa and, among other tasks, return to the effort of life-detection.

    In their recommendation, in fact, the NASA-appointed Science Definition Team said that the primary goal of the mission would be “to search for evidence of life on Europa.”

    The other goals are to assess the habitability of Europa by directly analyzing material from the surface, and to characterize the surface and subsurface to support future robotic exploration of Europa and its ocean.

    Scientists agree that the evidence is quite strong that Europa, which is slightly smaller than Earth’s moon, has a global saltwater ocean beneath its deep ice crust, and that it contains twice as much water as exists on Earth.

    For the ocean to be liquid there must be substantial sources of heat — from tidal heating based on the shape of its orbits, or from heat emanating from radioactive decay and entering the ocean through hydrothermal vents. All could potentially provide an environment where life could emerge and survive.

    Kevin Hand of the Jet Propulsion Laboratory is a specialist in icy worlds and is deputy project scientist for the Europa project. He was one of the co-chairs of the Science Definition Team (SDT) and he said the group was ever mindful of the complicated history of the Viking missions. He said that some people called Viking a “failure” because it did not clearly identify life, but he described that view as “entirely unscientific.”

    “It would be misguided to set out to ‘find life’,” he told me. “The real objective is to test an hypothesis – one we have that if you bring together the conditions for life as we know them, then they might come together and life can inhabit the environment.

    “As far as we can tell, Europa has the water, the elements and the energy needed to create a habitable world. If the origin of life involves some relatively easy processes, then it just might be there on Europa.”

    4
    This artist’s rendering shows NASA’s Europa orbiter mission spacecraft, which is being developed for a launch sometime in the 2020s. The mission would place a spacecraft in orbit around Jupiter in order to perform a detailed investigation of the planet’s moon Europa. The spacecraft will arrive at Jupiter after a multi-year journey, orbiting the gas giant every two weeks for a series of 45 flybys of Europa. NASA generally sends orbiters to a planet or moon before sending a lander. (NASA)

    The conclusions of the SDT team, which is made is up of dozens of scientists and engineers, will set the stage for further review, rather than for immediate action. The report goes to NASA, where it is assessed in relation to other compelling and competing missions. Both the Congress and White House can and do weigh in

    If it is approved, the Europa lander mission would be a companion to the already funded Europa multiple flyby mission scheduled to launch in the 2020s. While that spacecraft, the Europa Clipper, would have some capacity to determine whether or not the icy moon is habitable, a lander would be needed to search for actual signs of life.

    A mission to Europa was a top priority of the 2010 Decadal Review, a synthesis of potential projects in various disciplines that is reviewed by the National Research Council of the National Academy of Sciences.

    Its recommendations from the Decadal Review are generally followed by NASA. It remains unclear whether the Europa lander is a natural follow-on to the Europa Clipper or a new initiative to be judged on its own. But the project does have strong support — last year Rep. John Culberson (R-Tex.) pushed a bill through Congress making it illegal to not send a lander to Europa.

    Although there are many hurdles to clear for the Europa lander, the SDT report is nonetheless a rather momentous event since it strongly recommends a life-detection mission. So I thought it was worthwhile to include the entire preface of the team’s conclusions.

    “The Europa Lander Science Definition Team Report presents the integrated results of an intensive science and engineering team effort to develop and optimize a mission concept that would follow the Europa Multiple Flyby Mission and conduct the first in situ search for evidence of life on another world since the Viking spacecraft on Mars in the 1970s.

    The Europa Lander mission would be a pathfinder for characterizing the biological potential of Europa’s ocean through direct study of any chemical, geological, and possibly biological, signatures as expressed on, and just below, the surface of Europa. The search for signs of life on Europa’s surface requires an analytical payload that performs quantitative organic compositional, microscopic, and spectroscopic analysis on five samples acquired from at least 10 cm beneath the surface, with supporting context imaging observations.

    This mission would significantly advance our understanding of Europa as an ocean world, even in the absence of any definitive signs of life, and would provide the foundation for the future robotic exploration of Europa.”

    (Here is the full Europa lander SDT report.)

    Hand said that a lander would be a natural complement to the Europa Clipper, which is being designed to orbit Jupiter and pass by Europa 45 times at altitudes varying from 1675 miles to 16 miles. The flybys, he said, could potentially identify cracks and fissures in the crust of the moon, and thereby help identify where a lander should touch down.

    What’s more, images taken by the Hubble Space Telescope in 2012 suggest that Europa may be spitting out water in plumes that those clearly detected on Saturn’s moon, Enceladus.

    “If a plume was identified during a flyby, you better believe that we would do all we could to land somewhere close to it. The goal is to get as near as possible to the water coming out from under the crust because that’s how we’ll best learn whether that water has complex organic molecules, nitrogen compounds needed for life and possibly life itself.”

    If the lander project does get the green light in the months (or years) ahead, NASA would then put out a call to propose instruments that could search for the various chemical building blocks and manifestations life, as well morphological signs that life once was present. The search for life, in other words, would involve checking the boxes of building blocks or known molecular signs of possible life as they are found (or not found.)

    This is quite a different approach from that used during the Viking missions.

    Famously, the so-called “Labelled Release” experiments on both Viking 1 and Viking 2 met the criteria for having detected life as set out by NASA scientists before the mission began. Those criteria involved the detection of metabolism, the chemical processes that occur within a living organism in order to maintain life. A detection would imply the presence of life right on the harsh, irradiated Martian surface.

    In the LR experiment, a drop of very dilute aqueous nutrient solution was dropped into a sample collected of Martian soil. The nutrients (seven molecules that were products of the Miller-Urey experiment) were tagged with radioactive carbon 14 and the air above the soil was monitored for the evolution of radioactive CO2 gas. The presence of the gas was interpreted as evidence that microorganisms in the soil had metabolized one or more of the nutrients.

    5
    A picture of the Martian surface, as seen by NASA’s Viking 2 lander in 1976.

    The LR was followed with a control experiment, and the results consistently met the criteria for having detected “life.” Two other biology experiments on Viking, however, came up negative, including the one considered most conclusive — that no carbon-based organic material was detected in the soil, except for one interpreted as contamination from Earth.

    Subsequent Mars missions have strongly suggested that those organics interpreted as contamination were, in fact, organics interacting with perchlorate molecules now known to be common on the Martian surface. But despite this revision, the Mars science community remains broadly skeptical of the Labelled Release results, arguing that the CO2 could have been produced without biology. That, however, has not stopped LR principal investigator Gilbert Levin, and some others, from arguing now for forty years that the experiment did find life, creating a controversy that NASA has long struggled with.

    Hand said that in hindsight, “we can see that it didn’t make sense to look for metabolism until we knew a lot more. We need to follow the water, follow the carbon, follow the nitrogen, follow the complex molecules, and if all of that succeeds then we look for a living, breathing creature.”

    One of the inspirations for the hypothesis that Europa might harbor life under and within its ice is the recognition that frozen Antarctica also is home to microbial life. The most significant laboratory is Lake Vostok, an enormous collection of water beneath more than two miles of Antarctic ice.

    Researchers have determined that microbial life exists miles down through the ice. The distribution is small — something like 100 cells per milliliter of melted ice — but researchers have been trying for years to drill down into the lake and determine if the lake itself is home to more abundant life. The research has been done primarily by Russian scientists and engineers, and has been slowed by the harsh conditions and innumerable technical problems.

    6
    Three dimensional model of Lake Vostok drilling. (National Science Foundation)

    But as a proof of concept, Hand said, Lake Vostok and other subglacial lakes in Antarctica show that life can survive in freezing conditions. He said the science teams recommended that any life detection instrument that might go to Europa be able to identify life in the very low concentrations found at Vostok.

    Tori Hoehler, a research scientist at NASA’s Ames Research Center, is a specialist in microbial life in low energy environments (like Vostok and perhaps Europa,) and he is also a member of the Europa lander science definition team.

    “Our present understanding of Europa suggests that it is habitable, but it is more difficult to constrain how abundant or productive a Europan biosphere — should one exist — might be. For that reason, a conservative approach is to look to some of Earth’s most sparsely populated ecosystems when setting measurement targets for the lander.”

    But however low that abundance might be, the detection of anything with characteristics of life on Europa would be a huge advance for science.

    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 3:36 pm on April 13, 2017 Permalink | Reply
    Tags: , , , , , Many Worlds, Plumes on Enceladus   

    From Many Worlds: “Ocean Worlds: Enceladus Looks Increasingly Habitable, and Europa’s Ocean Under the Ice More Accessible to Sample” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-04-13
    Marc Kaufman

    1
    NASA’s Cassini spacecraft completed its deepest-ever dive through the icy plume of Enceladus on Oct. 28, 2015. (NASA/JPL-Caltech)

    It wasn’t that long ago that Enceladus, one of 53 moons of Saturn, was viewed as a kind of ho-hum object of no great importance. It was clearly frozen and situated in a magnetic field maelstrom caused by the giant planet nearby and those saturnine rings.

    That view was significantly modified in 2005 when scientists first detected signs of the icy plumes coming out of the bottom of the planet. What followed was the discovery of warm fractures (the tiger stripes) near the moon’s south pole, numerous flybys and fly-throughs with the spacecraft Cassini, and by 2015 the announcement that the moon had a global ocean under its ice.

    NASA/ESA/ASI Cassini Spacecraft

    Now the Enceladus story has taken another decisive turn with the announcement that measurements taken during Cassini’s final fly-through captured the presence of molecular hydrogen.

    To planetary and Earth scientists, that particular hydrogen presence quite clearly means that the water shooting out from Enceladus is coming from an interaction between water and warmed rock minerals at the bottom of the moon’s ocean– and possibly from within hydrothermal vents.

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

    A logical conclusion of these findings: the odds that Enceladus harbors forms of simple life have increased significantly.

    To be clear, this is no discovery of extraterrestrial life. But it is an important step in the astrobiological quest to find life beyond Earth.

    “The key here is that Enceladus can produce fuel that could be used by biology,” said Mary Voytek, NASA’s senior scientist for astrobiology, referring to the detection of hydrogen.

    2
    This graphic illustrates how scientists on NASA’s Cassini mission think water interacts with rock at the bottom of the ocean of Saturn’s icy moon Enceladus, producing hydrogen gas (H2). It remains unclear whether the interactions are taking place in hydrothermal vents or more diffusely across the ocean. (NASA)

    “So now on this moon we have many of the components associated with life — water, a source of energy and many of the important chemical building blocks. Nothing coming from Cassini will tell is if there is biology there, but we definitely have found another important piece of evidence of possible habitability.”

    The finding of molecular hydrogen (H2 rather a single hydrogen atom) in the Enceladus plumes was described in a Science paper lead by authors Hunter Waite and Christopher Glein of the Southwest Research Institute, headquartered in San Antonio.

    They went through a number of possible sources of the hydrogen and then concluded that the clearly most likely one was that chemical interaction of cool water and hot rocks — both heated by tidal forces in the complex Saturn system — at the bottom of the global ocean.

    “We previously thought that the water was heated but now we have evidence that the rocks are as well,” Waite told me. “And the evidence suggests that the rock is quite porous, which means that water is seeping through on a large scale and producing these chemical interactions that have a byproduct of hydrogen.”

    4
    The plumes of Enceladus originate in the long tiger stripe fractures of the south polar region pictured here. (Cassini Imaging Team, SSI, JPL, ESA, NASA)

    He said that the process could be taking place in and around those chimney-like hydrothermal vents, or it could be more diffuse across the ocean floor. The vent scenario, he said, was “easier to envision.”

    What’s more, he said, the conditions during this water-rock interaction are favorable for the production of the gas methane, which has been detected in the Enceladus plume.

    This is another tantalizing part of the Enceladus plume story because the earliest lifeforms on Earth are thought to have both consumed and expelled that gas. At this point, however, Waite said there is no way to determine how the methane was formed, which would be a key finding if and when it is made.

    “Our results leave us agnostic on the presence of life,” he said. “We don’t have enough information for that.”

    “But we now can make a strong case that we have a very habitable environment on this moon.” It’s such a strong case, he said, that it would be almost as scientifically interesting to not find life there than to detect it.

    One of the more interesting remaining puzzles is why the hydrogen is present in the plume in such unexpectedly substantial (though initially difficult to detect) amounts. If there was a large microbial community under the ice, then it could plausibly be argued that there wouldn’t be so much hydrogen left if they were consuming it.

    The possibilities: Waite said that it could mean there is just a lot of “food” being produced for potential microbes to survive on in the ocean, or that other factors limit the microbe population size. Or, of course, it could mean that there are no microbes at all to consume the hydrogen food.

    5
    Astronomers have twice found evidence of a plume of water vapor coming from the same location. Both plumes, photographed in UV light by Hubble, were seen in silhouette as the moon passed in front of Jupiter. (NASA/ESA/STScI/USGS)
    [Also shown today in a post from NASA/ESA Hubble]

    News of the Enceladus discovery came on the same day that other researchers announced that strong evidence of detecting a similar plume on Jupiter’s moon Europa using the Hubble Space Telescope.

    This was not the first plume seen on that larger moon of Jupiter, but is perhaps the most important because it appeared to be was spitting out water vapor in the same location as an earlier plume. In other words, it may well be the site of a consistently or frequently appearing geyser.

    “The plumes on Enceladus are associated with hotter regions,” said William Sparks of the Space Telescope Science Institute. “So after Hubble imaged this new plume-like feature on Europa, we looked at that location on the Galileo thermal map. We discovered that Europa’s plume candidate is sitting right on the thermal anomaly,”

    Sparks led the Hubble plume studies in both 2014 and 2016, and their paper was published in The Astrophysical Journal. He said he was quite confident, though not completely confident of the result because of the limits of the Hubble resolution. A 100 percent confirmation, he said, will take more observations.

    Since Europa has long been seen as a strong candidate for harboring extraterrestrial life, this is extraordinarily good news for those hoping to test that hypothesis. Now, rather than devising a way to blast through miles of ice to get to Europa’s large, salty and billions-of-years-old ocean, scientists can potentially learn about the composition of water by studying the plume — as has happened at Enceladus.

    As their paper concluded, “If borne out with future observations, these indications of an active European surface, with potential access to liquid water at depth, bolster the case for Europa’s potential habitability and for future sampling of erupted material by spacecraft.”

    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 9:57 am on April 10, 2017 Permalink | Reply
    Tags: , , , , Many Worlds, ,   

    From Many Worlds: “What Scientists Expect to Learn From Cassini’s Upcoming Plunge Into Saturn” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-04-10
    Marc Kaufman

    1
    Saturn as imaged from above by Cassini last year. Over the next five months, the spacecraft will orbit closer and closer to the planet and will finally plunge into its atmosphere. (NASA)

    NASA/ESA/ASI Cassini Spacecraft

    Seldom has the planned end of a NASA mission brought so much expectation and scientific high drama.

    The Cassini mission to Saturn has already been a huge success, sending back iconic images and breakthrough science of the planet and its system. Included in the haul have been the discovery of plumes of water vapor spurting from the moon Encedalus and the detection of liquid methane seas on Titan. But as members of the Cassini science team tell it, the end of the 13-year mission at Saturn may well be its most scientifically productive time.

    Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory (JPL) put it this way: “Cassini will make some of its most extraordinary observations at the end of its long life.”

    This news was first announced last week, but I thought it would be useful to go back to the story to learn more about what “extraordinary” science might be coming our way, with the help of Spilker and NASA headquarters Cassini program scientist Curt Niebur.

    And the very up close encounters with Saturn’s rings and its upper atmosphere — where Cassini is expected to ultimately lose contact with Earth — certainly do offer a trove of scientific riches about the basic composition and workings of the planet, as well as the long-debated age and origin of the rings. What’s more, everything we learn about Saturn will have implications for, and offer insights into, the vast menagerie of gas giant exoplanets out there.

    “The science potential here is just huge,” Niebur told me. “I could easily conceive of a billion dollar mission for the science we’ll get from the grand finale alone.”

    2
    The Cassini spacecraft will make 22 increasingly tight orbits of Saturn before it disappears into the planet’s atmosphere in mid-September, as shown in this artist rendering. (NASA/JPL-Caltech)

    The 20-year, $3.26 billion Cassini mission, a collaboration of NASA, the European Space Agency and the Italian Space Agency, is coming to an end because the spacecraft will soon run out of fuel. The agency could have just waited for that moment and let the spacecraft drift off into space, but decided instead on the taking the big plunge.

    This was considered a better choice not only because of those expected scientific returns, but also because letting the dead spacecraft drift meant that theoretically it could be pulled towards Titan or Enceladus — moons that researchers now believe just might support life.

    Although the spacecraft was sterilized before launch, scientists didn’t want to take the chance that some bacteria might remain in the capsule that could possibly contaminate the moons with life from Earth.

    So instead Cassini will be sent on 22 closer and closer passes around Saturn, into the region between the innermost ring and the atmosphere where no spacecraft has ever gone. On April 26, Cassini will make the first of those dives through a 1,500-mile-wide gap between Saturn and its rings as part of the mission’s grand finale.

    As it makes those terminal orbits, the spacecraft will have to be maneuvered with precision so it doesn’t actually fly into one of the rings. They consist of water ice, small meteorites and dust, and are sufficiently dense to fatally damage Cassini.

    “Based on our best models, we expect the gap to be clear of particles large enough to damage the spacecraft. But we’re also being cautious by using our large antenna as a shield on the first pass, as we determine whether it’s safe to expose the science instruments to that environment on future passes,” said Earl Maize, Cassini project manager at the NASA Jet Propulsion Lab. “Certainly there are some unknowns, but that’s one of the reasons we’re doing this kind of daring exploration at the end of the mission.”

    Then in mid-September, following a distant encounter with Titan and its gravity, the spacecraft’s path will be bent so that it dives into the planet itself. The final descent will occur in mid September, when Cassini enters the atmosphere where it will soon begin to spin and tumble, lose radio contact with Earth, and then ultimately explode due to pressures created by the enormous planet.

    All the while it will be taking pioneering measurements, and sending back images predicted to be spectacular.

    3
    The age and origin of the rings of Saturn remains a subject of a great debate that may soon come to an end. Ring particle sizes range from tiny, dust-sized icy grains to a few particles as large as mountains. Two tiny moons orbit in gaps (Encke and Keeler gaps) in the rings and keep the gaps open. (NASA)

    While the Cassini team has to keep clear of the rings, the spacecraft is expected to get close enough to most likely answer one of the most long-debated questions about Saturn: how old are those grand features, unique in our solar system?

    One school of thought says they date from the earliest formation of the planet, some 4.6 billion years ago. In other words, they’ve been there as long as the planet has been there.

    But another school says they are a potentially much newer addition. They could potentially be the result of the break-up of a moon (of which Saturn has 53-plus) or a comet, or perhaps of several moons at different times. In this scenario, Saturn may have been ring-less for eons.

    As Niebur explained it, the key to dating the rings is a close view of, essentially, how dirty they are. Because small meteorites and dust are a ubiquitous feature of space, the rings would have significantly more mass if they have been there 4.6 billion years. But if they are determined to be relatively clean, then the age is likely younger, and perhaps much younger.

    “Space is a very dirty place, with dust and micro-meteorites hitting everything. Over significant time scales this stuff coats things. So if the rings the rings are old, we should find very dirty ice. If there is little covering of the ice, then the rings must be young. We may well be coming to the end of a great debate.”

    A corollary of the question of the age of Saturn’s rings is, naturally, how stable they are.

    4
    Curt Neibur, lead program scientist at NASA headquarters for the Cassini mission. (NASA)

    If they turn out to be as old as the planet, then they are certainly very stable. But if they are not old, then it is entirely plausible that they could be a passing phenomenon and will some day disappear — to perhaps re-appear after another moon is shattered or comet arrives.

    Another way of looking at the rings is that they may well have been formed at different times.

    As Spilker explained in an email, Cassini’s measurements of the mass of the rings will be key. “More massive rings could be as old as Saturn itself while less massive rings must be young. Perhaps a moon or comet got too close and was torn apart by Saturn’s gravity.”

    The voyage between the rings will also potentially provide some new insights into the workings of the disks present at the formation of all solar systems.

    “The rings can teach us about the physics of disks, which are huge rings floating majestically and with synchronicity around the new sun,” Niebur said. “That said, the rings of Saturn have a very active regime, with particles and meteorites and micrometeorites smacking into each other. It’s an amazing environment and has direct relevance to the nebular model of planetary formation.”

    5
    This recently released Cassini image show’s moon Daphnis, which is embedded within a ring. The moon
    kicks up waves as it orbits within what is called the Keeler gap. This mosaic combines several previous images to show more waves in the gap edges. (NASA/JPL-Caltech)

    Another open question that scientists hope will be answered during the plunge is how long, precisely, is a day on Saturn.

    The saturnine day is often given as between 10.5 and 11 hours, but that lack of precision is unique in our solar system.

    The usual way to determine a planet’s rotation is to look for a distinctive point and watch to see how long it takes to reappear. But Saturn has thousands of miles of thick clouds between the rings and the core, and so no distinctive points have been found.

    The planet’s inner rocky core and outer core of metallic hydrogen create magnetic fields that potentially could be traced to measure a full rotation. But competing magnetic fields in the complex Saturn ring and moon system make that also difficult.

    “The truth is that we don’t know how long a day is on Saturn,” Niebur said. “But after the finale, we will finally know.”

    The answer will hopefully come by measuring the expected “wobble” of the magnetic field inside the rings. Since Cassini will pass beyond the magnetic interference of those rings, the probe should get the most precise magnetic readings ever taken.

    Project scientist Spilker is optimistic. “With the magnetic field we’ll be able to get, for the first time, the length of day for the interior of Saturn. If there’s just a slight tilt to the magnetic field, then it will wobble around and give us the length of a day.”

    6
    Artist rendering of Cassini over Saturn’s north pole, with it huge hexagon-shaped storm. (NASA/JPL-Caltech)

    Perhaps the most consequential findings to come out of the Cassini finale are expected to involve the planet’s internal structure and composition.

    The atmosphere is known to contain hydrogen, helium, ammonia and methane, but Niebur said that other important trace elements are expected to be present. The probe will use its mass spectrometer to “taste” the chemistry of the gases on the outermost edge of Saturn’s atmosphere and return the most detailed information ever about Saturn’s high-altitude clouds, as well as about the ring material.

    Instruments will also measure Saturn’s powerful winds (which blow up to 1,000 miles an hour), and determine how deep they go in the atmosphere. Like much about Saturn, that basic fact falls in the “unknown” category.

    For both Spilker and Niebur, the biggest prize is probably determining the size and mass of Saturn’s rocky core, made up largely of iron and nickel. That core is estimated to be 9 to 22 times the mass of the Earth, and to have a diameter of perhaps 18,000 miles.

    But these are broad estimates, and neither the size nor mass is really known. Those thousands of miles of thick clouds atop the atmosphere and the planet’s chaotic magnetic fields have made the necessary readings impossible.

    The Cassini instruments, however, are expected to make those measurements during its final months. As Cassini makes its close-in passes and then enters the atmosphere for the final plunge, it will send back the data needed to make detailed maps of Saturn’s inner magnetic and gravitational fields. These are what scientists need to understand the core and other structures that lay beneath the planet’s atmosphere.

    This work will compliment the parallel efforts underway at Jupiter, where the Juno mission is collecting data on that planet’s core as well. If scientists can measure the sizes and masses of both cores, they will be able to use that new information to answer many other questions about our solar system and beyond.

    “A better understanding Saturn’s interior, coupled with what Juno mission learns about the interior of Jupiter, will lead to (new insights into) how the planets in our solar system formed, and how our solar system itself formed,” Spilker said in an email.

    “This is then related to how exoplanets form around other stars. Studying our own giant planets will help us understand giant planets around other stars.”

    In other words, Saturn and Jupiter are planetary types expected to be found across the galaxies. And it’s our good fortune to be able to touch and learn from them, and to use that information to analyze distant planets that we can only indirectly detect or just barely see.

    NASA at Saturn: Cassini’s Grand Finale

    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 10:01 am on March 15, 2017 Permalink | Reply
    Tags: A Vision That Could Supercharge NASA, , , , , Hab-Ex, LUVOIR Mission Flyer, Many Worlds,   

    From Many Worlds: “A Vision That Could Supercharge NASA” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-03-15
    Marc Kaufman

    1
    LUVOIR Mission Flyer
    An artist rendering of an approximately 16-meter telescope in space. This image was created for an earlier large space telescope feasibility project called ATLAST, but it is similar to what is being discussed inside and outside of NASA as a possible great observatory after the James Webb Space Telescope and the Wide-Field Infrared Survey Telescope. Advocates say such a large space telescope would revolutionize the search for life on exoplanets, as well as providing the greatest observing ever for general astrophysics. (NASA)


    NASA/ESA/CSA Webb Telescope annotated


    NASA/WFIRST telescope

    Let your mind wander for a moment and let it land on the most exciting and meaningful NASA mission that you can imagine. An undertaking, perhaps, that would send astronauts into deep space, that would require enormous technological innovation, and that would have ever-lasting science returns.

    Many will no doubt think of Mars and the dream of sending astronauts there to explore. Others might imagine setting up a colony on that planet, or perhaps in the nearer term establishing a human colony on the moon. And now that we know there’s a rocky exoplanet orbiting Proxima Centauri — the star closest to our sun — it’s tempting to wish for a major robotic or, someday, human mission headed there to search for life.


    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    All are dream-worthy space projects for sure. But some visionary scientists (and most especially one well-known former astronaut) have been working for some time on another potential grand endeavor — one that you probably have not heard or thought about, yet might be the most compelling and achievable of them all.

    It would return astronauts to deep space and it would have them doing the kind of very difficult but essential work needed for space exploration in the far future. It would use the very costly and very powerful Space Launch System (SLS) rocket and Orion capsule being built now by NASA and Lockheed Martin respectively. Most important, it would almost certainly revolutionize our understanding of the cosmos near and far.

    At a recent meeting of the House Science Committee, chairman Lamar Smith, said of the hearing’s purpose that, “Presidential transitions offer the opportunities to reinvigorate national goals. They bring fresh perspectives and new ideas that energize our efforts.”

    That said, here’s the seemingly feasible project that fires my imagination the most.

    It has been quietly but with persistence promoted most visibly by John Grunsfeld, the former astronaut who flew to the Hubble Space Telescope three times to fix and upgrade it, who has spent 58 hours on spacewalks outside the Shuttle, and towards the end of his 40 years with the agency ultimately became an associate administrator and head of the agency’s Science Mission Directorate.

    3
    A visualization of the assembly in space of a large segmented telescope, with work being done by astronauts and robots. The honeycomb blocks are parts of the mirror, and the grey cylinders on the right are habitats for astronauts. (NASA)

    His plan: Build a segmented space telescope mirror that is 16 meters (52 feet) in diameter or larger, package it into one or several payload fairings and launch it into deep space. Accompanying astronauts would put it together either at its final destination or at a closer point where it could then be propelled to that destination.

    This would provide invaluable humans-in-space experience, would put the Orion and SLS to very good use in advance of a projected human mission to Mars, and would deploy the most penetrating telescope observing ever. By far.

    No mirror with a diameter greater than 3.5 meters (11.5 feet) has ever been deployed in space, although the the James Webb Space Telescope mirror will be substantially larger at 6.5 meters (21 feet) when launched in 2018. The largest ground telescopes are in the 10-meter (33 foot) range [for now].

    What Grunsfeld’s space behemoth would provide is an unprecedented power and resolution to see back to the earliest point possible in the history of the universe, and doing that in the ultraviolet and visible wavelengths. But perhaps more significantly and revolutionary, it would supercharge the agency’s ability to search for life beyond Earth.

    Like nothing else currently in use or development, it would provide a real chance to answer what is arguably humanity’s most fundamental question: Are we alone in the universe?

    Grunsfeld has been introducing people to the project/vision inside NASA for some time. He also told me that he has spoken with many members of Congress about it, and that most have been quite supportive. Now he’s starting to make the case to the public.

    “We need our leaders to be bold if we want to stay in the forefront of science and engineering,” he said. “Assembling a 16-meter telescope in space would not be easy by any means. But we can do it and — this is the key — it would be transformational. It’s a rational thing to do.”

    His confidence in the possibility of launching the segmented mirror parts and having astronauts assemble them in space comes, he says, from experience. Not only has he flown on the space shuttle five times and has his three very close encounters with the Hubble, but he has also overseen the difficult process of getting the JWST project — with its pioneering segmented, folding mirror — back on track after large budget overruns and delays. He’s also trained in astrophysics and is enamored of exoplanets.

    “If your goal is to search for inhabited planets, you just have to go up to the 16-meter range for the primary telescope mirror,” he said.

    “Think about it: if we sent up something smaller, it will give us important and potentially very intruiging information about what planets might be habitable, that could potentially support life. But then we’d have to send up a bigger mirror later to actually make any detection. Why not just go to the 16-meter now?”

    6
    The strongest driver on the size of the LUVOIR telescope is the desire to have a large sample of exoEarth candidates to study. This figure shows the real stars in the sky for which a planet in the habitable zone can be observed. The color coding shows the probability of observing an exoEarth candidate if it’s present around that star (green is a high probability, red is a low one). This is a visualization of the work of Chris Stark at Space Telescope Science Institute, who created an advanced code to calculate yields of exoplanet observations with different facilities. (C. Stark and J. Tumlinson, STScI)

    While all this may sound to many like science fiction, NASA actually has a team in place studying the science and technology involved with a very large space telescope, and has funded studies of in-space assembly as well.

    The current team is one of four studying different projects for a grand observatory for the 2030s. Their mission is called LUVOIR (the Large UV/Optical/IR Surveyor), and both it and a second mission under study (Hab-Ex) have exoplanets as a primary focus. It was Grunsfeld and Paul Hertz, director of NASA’s astrophysics division, who selected the four concepts for more in-depth study based in large part on astronomy and astrophysics community thinking and aspirations, especially as laid out in the 2013 Thirty-Year Astrophysics Visionary Roadmap.

    7
    Hab-Ex

    The LUVOIR team started out with the intention of studying the engineering and technological requirements — and science returns — of a space telescope between 8 and 16 meters in diameter, while Hab-Ex would look at the 4 to 7 meter option for a telescope designed to find exoplanets. Grunsfeld addressed the LUVOIR study team and encouraged them to be ambitious in their thinking — a message delivered by quite a few others as well. What’s more, a number of study team members were inclined towards the 16-meter version from the onset.

    he LUVOIR team has not addressed the issue of assembly in space — their goals are to understand the science made possible with telescopes of different sizes, to design an observatory that can be repaired and upgraded, and to determine if the technology to pull it all together is within reach for the next decade or two.

    A key issue is how large a folded up mirror the launch vehicle rocket nose cone (the fairing) can hold. While the current version of the SLS would certainly not accommodate a 16-meter segmented mirror, team study scientist Aki Roberge — an astrophysicist at the Goddard Space Flight Center — said that the team just recently got the good news that a next generation SLS fairing looks like it could well hold a folded mirror of up to 15 meters. Quite a few “ifs” involved, but still promising.

    “We’re still in the midst of our work, but it’s clear that a LUVOIR with a large aperture (mirror) gives us a major science return,” she said. “Going up to nine meters would be a major leap forward, and going to 16 would be a dramatic advance on that.”

    “But we have to assess what we gain in terms of going large and what we might lose in terms of added technical difficulty, cost and time.” As is, the 9 or 16-meter project — if selected — would not be ready to launch until the mid 2030s. All the great space observatories and missions have had decades-long gestation periods.

    The results from the LUVOIR and other formal NASA study teams will be reviewed by the agency and then assessed by a sizeable group of experts convened by the National Academy of Sciences for the 2020 Astrophysics Decadal Survey. They set the next decade’s topic and mission priorities for the astronomy and astrophysics communities (as well as others) — assessments that are sent back to NASA and generally followed.

    One of Grunsfeld’s goals, he told me, is to make the assembled-in-space 16-meter telescope a top Decadal Survey priority. While supportive of the LUVOIR efforts, he believes that including astronauts in the equation, deploying a somewhat larger mirror even if the difference in size is not great, and making a mirror that he says will be easier to fix and upgrade than a folded up version, gives the assembled-in-space option the advantage.

    These images, which are theoretical simulations using the iconic Hubble Deep Field image, are adjusted to reflect the light collected by telescopes of different sizes. They show the increased resolution and quality of images taken by a 16-meter telescope, a 9-meter, and the Hubble Space Telescope, which is 2.4 meters in diameter. They illustrate pretty clearly why astronomers and exoplanet hunters want ever larger telescope mirrors to collect those photons from galaxies, stars and planets.

    Whether or not the LUVOIR project is selected to be a future NASA flagship observatory, and whether or not it will be an assembled-in-space version of it, many at the agency clearly see human activity and habitation in space (as well as on planets or moons) as a necessary and inevitable next step.

    Harley Thronson is the senior scientist for Advanced Concepts in Astrophysics at Goddard, and he has worked on several projects related to how and where astronauts might live and work in space. He said this research goes back decades, having gained the attention of then-NASA Administrator Dan Goldin around 2000. It has recently experienced another spurt of interest as the agency has been assessing opportunities for human operations beyond the immediate vicinity of the Earth.

    “It’s inevitable that the astronomy community will want and need larger space observatories, and so we have to work out how to design and build them, how and where they might be assembled in space, and how they can be serviced,” Thronson said. The JWST will not be reachable for upgrades and servicing, and Congress responded to that drawback by telling NASA will make sure future major observatories can be serviced if at all possible.

    Thronson said that he supports and is inspired by the idea of a 16-meter space telescope, and he agrees with Grunsfeld that assembly in space is the wave of the future. But he said “I’m not quite as optimistic as John that we’re ready to attack that now, though it would be terrific if we were.”

    Part of Thronson’s work involves understanding operation sites where space telescopes would be most stable, and that generally involves the libration points, where countervailing gravity pulls are almost neutralized. LUVOIR, like JWST, is proposed for the so-called Sun-Earth L-2 point, about one million miles outward from Earth where the Earth and sun create a gravitational equilibrium of sorts.

    Thronson said there has been some discussion about the possibility of assembling a telescope at a closer Earth-moon libration point and then propelling it towards its destination. That assembly point could, over time, become a kind of depot for servicing space telescopes and as well as other tasks.

    8
    One of the locations in relatively nearby space where a space telescope would have a stable gravitational environment. (NASA


    LaGrange Points map. NASA

    As a sign of the level of interest in these kind of space-based activities, NASA last year awarded $65 million to six companies involved in creating space habitats for astronauts on long-duration missions in deep space.

    At the time, the director of NASA’s Advanced Exploration Systems, Jason Crusan, said that “the next human exploration capabilities needed beyond the Space Launch System rocket and Orion capsule are deep space, long duration habitation and in-space propulsion. We are now adding focus and specifics on the deep space habitats where humans will live and work independently for months or years at a time, without cargo supply deliveries from Earth.”

    Not surprisingly, building and maintaining telescopes and habitats in space will be costly (though less so than any serious effort to send humans to Mars). As a result, how much support NASA gets from the White House, Congress and the public — as well as the astronomy and astrophysics communities — will determine whether and when this kind of space architecture becomes a reality.

    John Grunsfeld, who has walked the walk like nobody else, plans to be stepping up his own effort to explain how and why this is a vision worth embracing.

    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 5:03 pm on February 16, 2017 Permalink | Reply
    Tags: , Many Worlds   

    From Many Worlds: “Ceres, Asteroids And Us” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-02-16
    Marc Kaufman

    1
    Ceres Up Close. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    For most of us, asteroids exist primarily as a threat. An asteroid that landed around the Yucatan peninsula, after all, is generally considered to have set into motion the changes that resulted in the elimination of the dinosaurs.

    Other large in-coming asteroids laid waste to swaths of Siberia in 1908, dug the world’s largest crater (118 mile wide) in South Africa long ago, and formed the Chesapeake Bay a mere 35 million years past. And another large asteroid will almost certainly threaten Earth again some day.

    There is, however, a reverse and possibly life-enhancing side to the asteroid story, one that is becoming more clear and intriguing as we learn more about them where they live. Asteroids not only contain a lot of water — some of it possibly delivered long ago to a dry Earth — but they contain some pretty complex organic molecules, the building blocks of life.

    The latest chapter in the asteroid saga is being written about Ceres, the largest asteroid in the solar system and recently declared to also be a dwarf planet (like Pluto.)

    Using data from NASA’s Dawn spacecraft, a team led by the National Institute for Astrophysics in Rome and the University of California, Los Angeles identified a variety of complex organic compounds, amino acids and nucleobases — the kind that are the building blocks of life.

    NASA/Dawn Spacecraft
    NASA/Dawn Spacecraft

    The mission has also detected signs of a possible subsurface ocean as well as cryovolcanos, which spit out ice, water, methane and other gases instead of molten rock.

    “This discovery of a locally high concentration of organics is intriguing, with broad implications for the astrobiology community,” said Simone Marchi, a senior research scientist at Southwest Research Institute and one of the authors of the paper in Science. “Ceres has evidence of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and now organic materials.”

    He said that the organic-rich areas include carbonates and ammonia-based minerals, which are Ceres’ primary constituents. Their presence along with the organics makes it unlikely that the organics arrived via another asteroid.

    In an accompanying comment in the Feb. 16 edition of Science, Michael Küppers of the European Space Astronomy Center in Madrid makes the case that Ceres might be, or might once have been, habitable.

    The paper provides “the first observations of organic material on Ceres, confirming the presence of such material in the asteroid belt,” he writes. “Furthermore, because Ceres is a dwarf planet that may still preserve internal heat from its formation period and may even contain a subsurface ocean, this opens the possibility that primitive life could have developed on Ceres itself. It joins Mars and several satellites of the giant planets in the list of locations in the solar system that may harbor life.”

    2
    Illustration of the minor bodies in the inner part of the Solar System, including Jupiter trojans and the main asteroid belt. These objects are byproducts of planet formation and have key information about that process. Detecting them in extrasolar systems may help us to understand the early evolution of planetary systems. (NASA)

    Asteroids are as ancient as the solar system, some 4.6 billion years old. They are the leftovers from the planet formation process that took place in the disk around the very early sun — pieces of rock that didn’t become parts of planets or moons and weren’t otherwise smashed to bits.

    Both their age and their composition have made asteroids increasingly interesting to space scientists studying how the solar system came to look and behave as it does. The result has been a suite of missions to asteroids organized by NASA, the Japanese Aerospace Exploration Agency (JAXA), the European Space Agency, the Russian space agency Roskosmos, and the China National Space Administration.

    Many of the missions include substantial collaboration between different national space agencies. The Dawn effort has major European involvement and NASA’s OSIRIS-REx mission to the asteroid Bennu and the Japanese Hayabusa2 mission to Ryugu each have three principal investigators from the other agency.

    NASA OSIRIS-REx Spacecraft
    NASA OSIRIS-REx Spacecraft

    hayabasu2-spacecraft
    JAXA Hayabasu 2 spacecraft

    Both spacecraft are now on their way, will spend months on their destination asteroids, and are designed to bring home samples (in 2018 for Hayabusa2 and 2023 for OSIRIS-REx.)

    NASA also approved two additional asteroid missions earlier this year. The first mission, called Lucy, will study asteroids, known as Trojan asteroids, trapped by Jupiter’s gravity.

    The Psyche mission will explore a very large and rare object in the solar system’s asteroid belt — an asteroid made of metal. Scientists believe it might be the exposed core of a planet that lost its rocky outer layers from a series of violent collisions. Lucy is targeted for launch in 2021 and Psyche in 2023.

    Left NASA Lucy; right NASA PSYCHE. NASA
    Left NASA Lucy; right NASA PSYCHE

    Why so many asteroid missions?

    I put the question to Harold C. Connolly Jr. of Rowan University, mission sample scientist for OSIRIS-REx and a co-investigator for the mission. He answered by email from Japan, together with Shogo Tachibana of Hakkaido University, who is a principal investigator for Hayabusa2. Both are co-principal investigators for the others’ sample analysis efforts.

    “The science is really driving the interest,” they wrote. “There now exists broader understanding that asteroids are time capsules to the past and can help illuminate the origin of Earth-like planets and potentially even the materials and conditions that lead to the origin of life.

    “The target asteroids of both missions are a treasure box of the earliest time period of the solar system, with such riches as prebiotic compounds (precursors to life-building organics) preserved in them.”

    In Japan, the Hayabusa2 mission is also a follow-on to the hugely popular original Hayabusa mission, which returned with grains from the asteroid Itokawa in 2010. Despite enormous difficulties and the failure of its lander, the spacecraft brought back enough sample to tell scientists that the asteroid was four billion years old, at one time was exposed to temperatures of 800 degrees centigrade, and much more.

    Hayabusa inspired so much interest in Japan that it led to not only the follow-on mission but also three movies, including one with star actor Ken Watanabe.

    In a phone conversation, Küppers of the European Space Astronomy Center expanded on the scientific importance of asteroids.

    He said that Ceres research has already determined that asteroid most likely was formed further out in the solar system and then migrated in. This conclusion flows from the observed presence of geological features and minerals on the surface that require the presence of water to form. Closer-in asteroids are believed to have had any water baked out of them, strongly suggesting that Ceres was once further from the sun.

    That asteroidal (and cometary) water plays an important role in the history of Earth. “The oceans on Earth certainly could have been filled with water, and organic compounds, from asteroids like Ceres,” Küppers said. Different kinds of water have different isotopic signatures, and the water signature on Earth is very much like that detected in some asteroids and comets.

    The Dawn spacecraft has already visited the large asteroid Vesta on its mission, and found minerals formed in water, a geology with steep cliffs and landslides, and the presence of an enormous crater at one of the poles. For Vesta, as for Ceres, a primary goal of the Dawn mission is to map the asteroid in various ways and with substantial precision. The overall goal, however, is to explore the conditions and processes found worlds as old as the solar system.

    While Vesta is a described as a “protoplanet” because of its size, Ceres is considered a dwarf planet (as well as an asteroid) because it has sufficient mass and gravity to be rounded like a planet. Vesta, and the other asteroids, are not. Itokawa, below, is considerably smaller than Ceres or Vesta, and so has been rounded far less.

    3
    Ceres, the largest asteroid in the solar system, features areas with concentrations of shiny, white material. Scientists have described them as likely to be salts and ice. The dwarf planet contains about one third of the mass in the asteroid belt between Mars and Jupiter, yet it is still dwarfed in size by our moon. The more detailed images was taken by Dawn from 3,200 miles away. NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

    4
    NASA’s Dawn spacecraft captured this image of the asteroid Vesta while in orbit on July 18, 2011. The view looks across Vesta’s cratered and heavily-scarred south pole from a distance of about 6,500 miles. Vesta is the last remaining rocky protoplanet of the kind that formed the terrestrial planets. Numerous fragments of Vesta were ejected by collisions one and two billion years ago that left two enormous craters occupying much of Vesta’s southern hemisphere. Debris from these events has fallen to Earth as meteorites which have been a rich source of information about Vesta. (NASA/JPL-Caltech/UCLA/MPS)

    What was planned to be the biggest NASA asteroid mission is the Asteroid Redirect Mission. It was proposed as the first robotic mission to visit a large near-Earth asteroid, to collect a multi-ton boulder from its surface, and to then redirect it into a stable orbit around the moon. Once in orbit around the moon, astronauts would explore it and return with samples in the 2020s.

    The proposed mission was driven by science, but also was part of NASA’s plan to advance the new technologies and spaceflight experience needed for a human mission to the Martian system in the 2030s. What’s more, some space scientists are concerned about the possibility of a large asteroid heading our way, and they want to develop techniques for just slightly changing an in-coming asteroid’s path so it would miss Earth.

    Many in Congress were never excited by the asteroid re-direct plan, and the future of the mission remains quite uncertain.

    But the part of the mission involved with learning more about asteroid pathways and how they might be changed is still, at least indirectly, alive.

    That’s because the asteroid Bennu, the destination for OSIRIS-REx, is one that often comes close to the Earth. (The acrony, by the way, stands for the Origins Spectral Interpretation Resource Identification Security Regolith Explorer.)

    As explained on the NASA OSIRIS-REx webside, “Bennu is a B-type asteroid with a ~500 meter diameter. It completes an orbit around the Sun every 436.604 days (1.2 years) and every 6 years comes very close to Earth, within 0.002 astronomical units (the term used to describe the distance from the sun to Earth.) These close encounters give Bennu a high probability of impacting Earth in the late 22nd century.”

    Some place that probability considerably lower, but it is nonetheless a sobering thought given the damage that asteroids have periodically inflicted on the Earth.

    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 10:43 am on February 2, 2017 Permalink | Reply
    Tags: , , Atmospheres can protect and nurture or they can destroy, “L” is for the longevity of a potentially civilized intelligent world, , , , , , Many Worlds, , The fate of Earth is indeed in our hands   

    From Many Worlds: “Do Intelligent Civilizations Across the Galaxies Self Destruct? For Better and Worse, We’re The Test Case” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-02-01
    Marc Kaufman

    1
    The Eastern Seaboard as seen from the International Space Station in 2012. (NASA)

    In 1950, while working at Los Alamos National Laboratory, renowned physicist Enrico Fermi was lunching with colleagues including Edward Teller, Herbert York an Emil Konopinski. The group talked and laughed about a spate of recent UFO reports during the meal, as well as a cartoon about who might be stealing garbage can top.

    A bit later in the meal Fermi famously asked more seriously, “Where are they?” Sure, there were many bogus reports back then about alien flying saucers, but Fermi was asking what has turned out to be a significant and long-lasting question.

    If there are billions of exoplanets out there — as speculated back then but proven now — why have there been no bona fide reports of advanced extraterrestrials visiting Earth, or somehow leaving behind their handiwork?

    Many answers have been offered in the following decades — that we are alone in the universe, that the distances between solar systems are too great to travel, that Earth became home to life early in the galaxy’s history and other planets are only now catching up, that life might be common in the universe but intelligent life is not.

    I would like to focus on another response, however, one that came to mind often while reading a new book by the former holder of the astrobiology chair at the Library of Congress, planetary scientist David Grinspoon.

    This potential explanation is among the most unsettling: that intelligent and technologically advanced beings are likely to ultimately destroy themselves. Along with the creativity, the prowess and the gumption, intelligence brings with it an inherent instinct for unsustainable expansion and unintentional self destruction.

    I should say right off that this is not a view shared by Grinspoon. His Earth in Human Hands, in fact, argues with data and conviction that humans are more likely than not to ultimately find ways to work together and avoid looming global threats from climate change, incoming asteroids, depleting the ozone layer and myriad other potential sources of mass extinction.

    But his larger point is the sobering one: that the fate of Earth is, indeed, in our hands. We humans are a force shaping the planet that is as powerful as a ring of volcanoes, a giant impactor from space, the long-ago rise of lifeforms that could, and did, dramatically change our atmosphere and along the way caused near global extinction.

    It may sound odd, but as he sees it we are now the planet’s most powerful and consequential force of nature.

    2
    Since the Industrial Revolution and the spread of technology over the past 200 years, humans have become the dominant force on the planet, says David Grinspoon, the first Chair in Astrobiology at the Library of Congress. (Credit: Tony Steele)

    “What I’ve sought to do is describe what is reality on our planet,” Grinspoon told me. “Some people have been hostile and told me it’s arrogant to say humans have so much control over the fate of the planet, and I agree that it’s a sobering thing.”

    But the Earth has been and will be dramatically changed by us. The big question for the future is whether change can be for the better, or will it be unsustainable and for the worse.”

    While Grinspoon’s major themes involve competing paths for the future of our planet, they consistently are based on and informed by knowledge gained in recent decades about planets in our solar system and those very far away. The logic and track record of the search for intelligent life beyond Earth (SETI) also plays a role, as does the author’s relationships — initially via family in childhood — with Carl Sagan and some of the scientists he mentored.

    For instance, Grinspoon has studied Venus and the evolution of its atmosphere. He says that an understanding of the runaway greenhouse effect that created surface temperatures of 800 degrees F has been instumental in the study of climate change on Earth.

    3
    David Grinspoon is a senior scientist at the Planetary Science Institute, and the author of “Earth in Human Hands.”

    Similarly, the disappearance of much of the Martian atmosphere left the once warmer planet frigid and likely lifeless. Sagan’s work on the dust storms of Mars, which have the effect of making the planet colder still, was an early scientific foray into understanding the importance of atmosphere and climate on a potential biosphere. So was Sagan’s work on the possible effects of atomic war — the globally life-destroying “nuclear winter.”

    The clear inference: Planetary atmospheres can change, as ours is doing now with major buildups in carbon dioxide. Atmospheres can protect and nurture, or they can destroy.

    And Exhibit A is the three rocky solar system planets in what is a slightly expanded habitable zone. But only one supports life.

    The buildup of carbon dioxide in the atmosphere and oceans since the onset of the industrial revolution, Grinspoon writes, is a prime example of how intelligent people and their technology can unintentionally have a huge impact on nature and the planet. The jury remains out as to how humanity will respond.

    But Grinspoon also points to the way that nations around the globe responded to the discovery that the ozone layer was being depleted as an example of how humanity can repair unintentional yet potentially extinction-threatening challenges.

    It took a while, but the artificial refrigerants — chlorofluorocarbons (CFCs) — causing the damage were ultimately curtailed and then banned, and there are signs that the worrisome holes in the ozone layer are if not shrinking, at least no longer growing.

    4
    The Drake equation, created by astronomer Frank Drake in 1961, assesses the probability of how many planets in our galaxy might have civilizations that can communicate. The last factor — the “L” for longevity — is considered key. Drake was one of the founders of SETI, and its effort to detect signals from intelligent life beyond Earth.

    This brings us back to the Fermi paradox, and the apparent absence of signs of extraterrestrial intelligence.

    Fermi, and many others, have assumed that successful, technological civilizations elsewhere would have the desire and ultimately know-how to expand beyond their original planet and colonize others. Indeed, early SETI gatherings here and in the former Soviet Union took that drive to expand for granted, a reflection of attitudes of the times.

    This presumed drive to colonize was often discussed as either a kind of biological imperative or an acknowledgement that these “intelligent” civilizations are likely to have seriously damaged their own planets through unsustainable and hazardous growth. Either way, they would be on the move.

    Yet after more than a half century of listening for signals from these presumed intelligent and mobile beings, the SETI effort to detect such life via radio telescopes has come up empty. There are many potential reasons why, but let’s focus on the one introduced earlier.

    The pioneering Drake equation, first put forward in 1961, attempts to assess the probability of finding intelligent civilizations beyond Earth based on factors such as rate of star formation in the galaxy, the number of planets formed and then the percentage with life, then the number with complex life and finally intelligent and technologically-sophisticated life. But it’s the “L” at the end of the equations, says Grinspoon, that is widely considered the most important.

    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA
    SETI/Allen Telescope Array situated at the Hat Creek Radio Observatory, 290 miles (470 km) northeast of San Francisco, California, USA

    The “L” is for the longevity of a potentially civilized, intelligent world, or “the length of time over which such civilizations release detectable signals.”

    Of all the components of the Drake equation, which is filled with unknowns and partially known estimates, L is no doubt the least well defined. After all, no extraterrestrial life, and certainly no intelligent life, has ever be detected.

    Yet as describe by Grinspoon, “L” — which for Earth is about 200 years now — is the key.

    “Let’s say that it’s impossible for a civilization with very powerful technology to last for 10,000 years, or even 1,000 years. That makes the likelihood of ever making contact with them vanishingly small even if life and intelligence are out there. The chances of them being close enough to detect and communicate with are pretty much nil.”

    If the opposite is true, if it’s possible for a civilization to get over their technological adolescence, then they ought to be detectable. Actually, they could last for millions of years using their technology to enhance and protect the planet.”

    Planets face all kinds of dire threats, and catastrophes and extinctions are the rule. But if technology can be used intentionally for the benefit the planet — like protecting it from an asteroid or avoiding the next Ice Age – longevity would clearly improve greatly.”

    This interstellar view, he says, helps to see more clearly what is happening on Earth. Now that through our technologies we have become the prime movers regarding the planet’s health and safety, it is really up to us as a species to choose between allowing these “advances” to knowingly or unintentionally harm the planet, or to consciously use technology to make it better.

    Grinspoon does not see our current century as one when the effects of technology are likely to be intentionally positive. But he does see the movement towards a more sustainable planet to be irreversible, whatever blips might come our way. What’s more, he said, fossil fuels will be largely gone by 2100 and there’s reason to believe the world’s human population will have stabilized — two enormous changes that favor a longer-lived human civilization.

    “The long-held view that humans will always expand, that they will maintain that biologically primitive imperative, that growth is always good — it’s interesting to wonder if those assumptions aren’t inherently wrong,” he said.

    “I suggest that true ‘intelligence’ able to sustain itself involves an inherent questioning of those values, and that a more measured and strategic growth pattern, or even material stasis might be values that come with a more universal intelligence.”

    Whether that intelligence is on Earth or many hundreds of light years away.

    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.

     
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