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  • richardmitnick 3:45 pm on September 21, 2017 Permalink | Reply
    Tags: , , Complexity is indeed the desired endpoint, Earth-Life Science Institute (ELSI) in Tokyo, Hyperbranched polymers, Many Worlds,   

    From Many Worlds: “Messy Chemistry: A New Way to Approach the Origins of Life” 

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    Many Worlds

    2017-09-21
    Marc Kaufman

    1
    Astrobiologist and chemist Irena Mamajanov and prebiotic chemist Kuhan Chandru in their messy chemistry garb at the Earth-Life Science Institute (ELSI) in Tokyo. Mamajanov leads an effort at the institute to study a new “messy” path to understanding how some prebiotic chemical systems led to building blocks of life on early Earth. (Nerissa Escanlar)

    More than a half century ago, Stanley Miller and Harold Urey famously put water and gases believed to make up the atmosphere of early Earth into a flask with water, sparked the mix with an electric charge, and produced amino acids and other chemical building blocks of life.

    The experiment was hailed as a ground-breaking reproduction of how the essential components of life may have been formed, or at least a proof of concept that important building blocks of life could be formed from more simple components.

    Little discussed by anyone outside the origins of life scientific community was that the experiment also produced a lot of a dark, sticky substance, a gooey tar that covered the beaker’s insides. It was dismissed as largely unimportant and regrettable then, and in the thousands of parallel origins of life experiments that followed.

    Today, however, some intrepid researchers are looking at the tarry residue in a different light.

    Just maybe, they argue, the tar was equally if not more important as those prized amino acids (which, after all, were hidden away in the tar until they were extracted out.) Maybe the messy tar – produced by the interaction of organic compounds and an energy source — offers a pathway forward in a field that has produced many advances but ultimately no breakthrough.

    Those now studying the tar call their research “messy chemistry,” as opposed to the “clean” chemistry that focused on the acclaimed organic compounds.

    There are other centers where different versions of “messy chemistry” research are under way — including George Cody’s lab at the Carnegie Institution for Sciences and Nicholas Hud’s at the Georgia Institute of Technology — but it is probably most concentrated at the Earth-Life Science Institute in Tokyo (ELSI.)

    There, messy chemistry is viewed as an ignored but promising way forward, and almost a call to arms.

    “In classical origin-of-life synthetic chemistry and biology you’re looking at one reaction and analyzing its maximum result. It’s A+B = C+D,” said Irena Mamajanov, an astrobiologist with a background in chemistry who is now a principal investigator ELSI and head of the overall messy chemistry project.

    “But life is not like that; it isn’t any single reaction. They’re looking at a subset of reactions and we ask: ‘Why not look at the whole complex system?’”

    2
    rena Mamajanov of ELSI, with colleague Yuki Suna, synthesizes particular complex molecules similar to enzymes to explore the many pathways that could have been involved in the production of actual early enzymes. The term “messy chemistry” grew out of an prebiotic chemistry conference at the Carnegie Institution of Science in Washington several years ago. (Nerissa Escanlar)

    There’s a scientific lineage here – researchers have worked with complex systems and reaction systems in many fields, and in principle this is the same. It’s taking a “systems” approach and applying it to that black box period on Earth when non- biological chemicals were slowly transformed (or transformed themselves) into chemical systems with the attributes of “life.”

    The messy chemistry work is getting noticed, and Mamajanov was a featured speaker on the “New Approaches to the Origins of Life” plenary at the 2017 Astrobiology Science Conference, in Mesa, Arizona. At ELSI alone, researchers have been working on messy chemistry using metals, using electricity, using radioactivity, using computational chemistry and using analytical chemistry to tease out patterns and structure in the tars.

    Mamajanov says this messy chemistry approach – which she learned to some extent as a fellow at both Carnegie and Georgia Tech — makes intuitive, as well as scientific sense because life is nothing if not complex.

    Wouldn’t it be logical for the origin of life to be found in some of the earliest complex systems on Earth. rather than in looking for straight-line processes that progress almost independent of all the chemistry happening around them?

    It stands to reason that the gunky tar played a role, she said, because tars allow some essential processes to occur. Tars can concentrate compounds, can encapsulate them, and can provide a kind of primitive (messy) scaffolding that could eventually evolve into the essential backbones of a living entity.

    It’s the structure, in fact, that stands out as a particularly promising aspect of messy chemistry. More traditional synthetic biology is looking for simple molecular structures created by clean reactions, while messy chemistry is doing the opposite.

    The goal of messy chemists is to see what interesting chemical processes take place within a defined portion of the messy, complex sample. What unexpected, surprising compounds or chemical structures might be formed? And how might they shed light on the process of chemical self-organization and more generally the origin of life question?

    In her lab on the basement floor of the ELSI main building, Mamajanov works with colleagues to synthesize her messy molecules and push further into understanding their structures, their potential ability to adapt, and their suitability as possible precursors to the RNA and DNA molecules that characterize life.

    Her specific area of study is hyperbranched polymers – three-dimensional, tree-shaped chains of repeating molecules that connect with other similar molecules. The result is globular, presents multitudes of chemical reactions and has some hidden and protected spaces inside their globs. Related synthetic, or bio-mimicked chemicals (i.e., modeled on biological compounds and processes) have been used by the drug industry for some time.

    With these hyperbranched polymers, Mamajanov has worked to produce pathways within the messy systems where the polymers show characteristics of evolvability.

    Her hyperbranched polymers are synthetic, as are those of noted synthetic chemists–in-search-of-biology such as Steven Benner, at the Foundation for Applied Molecular Evolution and Gerald Joyce of the Scripps Institute.

    But the starting points are quite different, as are the goals. The two men are working to create clean chemical systems that produce the building block molecules that they want, but without the tar. Mamajamov is intentionally making tar.

    Eric Smith, a specialist in complexity systems, physics and chemistry who is also at ELSI sees the messy approach as containing the seeds of an important new way forward. “What is now called messy chemistry used to be completely out of the mainstream,” he said. “That is no longer the case.”

    Smith described how John Sutherland of the Laboratory of Molecular Biology at Cambridge, U.K. won accolades for his work on the prebiotic assembly of important building blocks for RNA, using controlled chemistry that avoided all the messiness.

    But he was also criticized later for using a such a controlled model – early Earth, after all, did not have any outside controller – and Smith said Sutherland is incorporating the messier side of prebiotic chemistry today, although tar remains an enemy rather than a potential friend.

    “Now he’s going back to a one pot synthesis, allowing reactions that would have to be less controlled than what he was doing before,” Smith said of Sutherland. “He may do it in a way quite different from Irena and others involved in messy chemistry, but it seems to allow for many more complex reactions.”

    And complexity is indeed the desired endpoint. Not simply repetitive reactions and not random ones, but rather reactions that are very complex but ultimately structured.

    This is where another novel aspect of the messy chemistry approach comes into play: Mamajanov and others at ELSI are collaborating with practitioners of “artificial chemistry,” computer simulated versions of what could be happening in messy interactions.

    The work is being done primarily by Nathaniel Virgo, an artificial life specialist who uses computing to learn about how chemical systems behave once you leave the laboratory world where the number of chemical components is small and controlled.

    And his big question: “Are there situations in which you can get ‘order from disorder’ in chemistry – to start with a messy system and have it spontaneously become more ordered? If so, what kinds of conditions are required for this to happen, and what kinds of ordered states can result?

    Mamajanov needs Virgo’s computations to analyze and project forward what a messy chemical system might do, since the sheer number of possible chemical reactions involved is huge. And Virgo needs the messy chemistry as a test bed of sorts for his abstracted questions about, in effect, making order out of what appears to be chaos. They are, for each other, hypothesis-generating machines.

    Virgo pointed to several primary reasons why computational work is important for answering the question of creating order from disorder (and ultimately, he is convinced, life from non-life.)

    “The first is simply that studying messy chemistry experimentally is really hard. If you have a test tube containing a mess, it takes a lot of work to find out what molecules are in it, and basically impossible to know what reactions are happening, at least not without an enormous amount of work. In contrast, in a simulation you know exactly what molecules and reactions are present, even if there are millions of different types.”

    The second reason involves the fundamental issue of studying specific chemical systems versus studying general mechanisms.

    “As a complex systems scientist, I first want to know what, in general, is required, for a given phenomenon to occur. Once this is known, it should become clear which real systems will exhibit the right kinds of properties.

    “This allows us to narrow down the vast space of possible hypotheses for the origins of life, rather than simply testing them one at a time. It should also give us some insight into the question of whether life might be possible with completely different kinds of chemistry than the protein-nucleic acid-metabolite chemistry we have on Earth.

    From his studies he has found that in messy chemical systems, chemical self-production occurs and tht the systems can change dramatically in response to small changes such as an increased temperature.

    “This suggests that messy chemistry is fundamentally qualitatively different from clean chemistry – adding more species doesn’t just mean the system gets harder to study, it also means that fundamentally new things can happen.”

    And in the origins of life world, things are happening.

    See the full article here .

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    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

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  • richardmitnick 10:56 am on September 6, 2017 Permalink | Reply
    Tags: , , , , Many Worlds, NASA's future   

    From Many Worlds: “Is That the Foundation of NASA I Feel Shifting?” 

    NASA NExSS bloc

    NASA NExSS

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    Many Worlds

    2017-09-06
    Marc Kaufman

    1
    A lunar outpost was an element of the George W. Bush era Vision for Space Exploration, which has been replaced with President Barack Obama’s space policy. The outpost would have been an inhabited facility on the surface of the Moon. At the time it was proposed, NASA was to construct the outpost over the five years between 2019 and 2024. Now the man nominated to be the next NASA administrator, James Bridenstine, is a strong and vocal advocate of building a moon colony.(NASA)

    Reading about some of the views coming from the man recently nominated to become NASA’s Administrator, Rep. James Bridenstine of Oklahoma, I heard the sound of a door closing.

    Other doors will surely be opened if he is confirmed by the Senate, but that shutting door happens to be to the gateway to a realm that has engrossed and nurtured me and clearly many millions of Americans.

    What is happening, I fear, is that our Golden Age of space science, of exploration for the sake of expanding humanity’s knowledge and wonder, is about to wind down. The James Webb Space Telescope will (probably) still be launched, and missions to Europa and Mars are on the books. But to be a Golden Age there must be an on-going vision for the future building on what has been accomplished.

    NASA/ESA/CSA Webb Telescope annotated

    When it comes to space science, that clearly takes strong government support and taxpayer money. And if what I’m reading is correct, a lot of that future NASA funding for exploring and understanding the grand questions of space science will be going instead to setting up and maintaining that colony on the moon.

    And the goals Bridenstine appears to have in mind when he speaks of setting up a moon colony are decidedly military, strategic and commercial. As when Vice President Mike Pence spoke to NASA workers at the Kennedy Space Center to telegraph the Trump Administration’s space vision, space science is essentially an afterthought.

    Media coverage of the Bridenstine selection has tended to focus on the fact that he’s a politician and that he has earlier been quite critical of climate change science.

    But what concerns me most are his views about space science in general. Because with the money and focus a major moon colony project would take, NASA’s space science initiatives run the risk of returning to the back seat they occupied in the agency’s earlier days.

    2
    Rep. Jim Bridenstine, R-Okla., addresses the Space Symposium in Colorado Springs in 2016. (Tom Kimmell)

    A former jet pilot, director of the Tulsa Air and Space Museum and an early supporter of then candidate Donald Trump, Bridenstine has been clear for a long time about his priorities in space. I think we have to assume they correspond to the views of those in the White House.

    In a speech last year to the Lunar Exploration Group titled This is Our Sputnik Moment[Title stolen from then Energy Secretary Stephen Chu], he pointed to what he described as a major missed opportunity the mid 1990s “discovery” of water at the poles of the moon by a Defense Department mission. (It was actually a Navy-NASA mission that first made the detection, and it hinted at the presence of water rather than proving anything. The proof came later via missions by NASA, the Japanese space agency, the Chinese space agency and perhaps most important, the Indian space agency.)

    Here are excerpts from the talk he gave, which I am quoting at length to to give a better feel for his mindset and for the kind of change he is proposing. These are points consistent with talks he has given many times before and are memorialized in his proposed American Space Renaissance Act. American space activities, he makes clear, should focus first and foremost on cis-lunar space, the area between the moon and Earth.

    “This single discovery” of frozen water on the moon, he said, “should have immediately transformed America’s space program. Water ice not only represents a critical in situ resource for life support (air and water); it can be cracked into its components, hydrogen and oxygen, to create the same chemical propellant that powered the Space Shuttle.

    “From the discovery of water ice on the moon until this day, the American objective should have been a permanent outpost of rovers and machines at the poles with occasional manned missions for science and maintenance. The purpose of such an outpost should have been to utilize the materials and energy of the moon to drive down the costs and increase the capabilities of cis-lunar space. Let’s talk about why.

    “The watershed discovery of lunar ice happened at a time when space was transforming all of our lives, ” he continued. “Today, our very way of life depends on space. We have transformed how we communicate, navigate, produce food and energy, conduct banking, predict weather, perform disaster relieve, provide security, and so much more.

    “Each of these market segments continues to grow and improve the human condition on Earth, but a 2013 study by the Inter-Agency Space Debris Coordination Committee determined that the debris population in low earth orbit will continue to grow due to collisions even if nothing new is launched. Catastrophic collisions such as Iridium 33-Cosmos 2251 [which took place in 2009] will occur every five to nine years. Each such collision will create thousands of pieces of debris and result in more collisions.”

    With so many satellites and much debris in low-earth orbit, Bridenstine said, it has become increasingly hazardous to send up multi-million and billion-dollar satellites. One way to limit the congestion, he said, is to make satellites fly higher and live longer, and that means getting them additional fuel to stay on course. The way to do that, he argues, is to gear up that envisioned water-cracking facility on the moon to produce the hydrogen to refuel satellites. A potentially reasonable series of points.

    3
    Spent space satellites and debris, including that from a Chinese missile fired in 2007 that broke up one of the nation’s older weather satellites, are making low-Earth orbiting more hazardous. Can hydrogen fuel from cracked water ice on the moon help break the logjam by servicing satellites further from Earth and allowing them to orbit for longer periods of time? (NASA)

    Then comes what would be a real game-changer:

    “This is only possible because of all the risk that the government has already retired for these capabilities. Now, the U.S. government should play a part in developing the tools for lunar energy resource development, cis-lunar satellite servicing, and maintenance. The U.S. government must work to retire risk, make the operations routine, and once again empower commercial companies.

    In other words, the U.S. government and presumably NASA should do the heavy lifting to create (and fund) this architecture so that commercial companies — among others — can profit from it.

    This investment, he said, “has already worked to an extent in low Earth orbit, and now we should apply this model to cis-lunar space. This is not only appropriate for economic development and to improve the human condition on Earth, but to provide for national security, which is now entirely dependent on space-based capabilities. Every domain of warfare today depends on space.

    “Once the cis-lunar market develops to service and maintain our traditional space-based military and commercial capabilities, other opportunities will naturally follow. The surface of the moon is composed mainly of oxides of metals: iron, magnesium, aluminum, silicon, titanium and others.

    4
    Raw platinum

    “While these oxides can be used to produce oxygen for life support and metals for additive manufacturing in situ, they will not likely be exported to earth. However, it is possible, if not likely, that highly valuable platinum group metals are much more available on the moon from astroblemes than they are on earth.

    “Such a discovery with cis-lunar transportation capabilities would fundamentally transform American commercial lunar development and could profoundly alter the economic and geopolitical balance of power on Earth. This could explain the Chinese interest in the moon. The question is: What are WE, the United States, doing to make sure the free world participates economically in such a discovery? The U.S. government has a role to play here.

    “Competition for locations on the moon (the poles) and resources is inevitable. It must be stated that constitutionally, the U.S. government is required to provide for the common defense. This includes defending American military assets in space AND commercial assets in space, many of which have and will have a dual role of providing commercial and military capabilities. President Kennedy said, ‘Whatever men shall undertake, free men must fully share.’

    “The U.S. government must establish a legal framework and be prepared to defend private and corporate rights and obligations all within keeping the Outer Space Treaty. And to enable freedom of action, the United States must have cis-lunar situational awareness, a cis-lunar presence, and eventually must be able to enforce the law through cis-lunar power projection. Cis-lunar development will either take the form of American values with the rule of law, or it will take the form of totalitarian state control. The United States can decide who leads.”

    So this is where a moon colony leads us as viewed by a proponent: to a day when satellites and spacecraft can be fueled with lunar hydrogen while in space, but also with potential turf wars on the moon over the source of that precious hydrogen fuel. To an expansion of American might and power to meet the perceived need to dominate space between Earth and the moon. And to a desire to exploit the moon for platinum and potentially other riches.

    The only references I’ve seen from Bridenstine about space science are that a moon colony could be a good refueling and take-off point for travel to deeper space, and the belief that while sending humans to Mars should be a long-range vision, it isn’t going to happen anytime soon. In fairness, it must be said that Bridenstine has pretty consistently voted in favor of NASA space science projects in the past, and he has not shown hostility towards planetary or orbiting observatory missions. But that was before there was a costly moon colony infrastructure to potentially build.

    In some ways a NASA U-turn like this was almost inevitable. The agency that made its historic mark with the Apollo program has been, with limited exceptions, out of the humans-to-space business for years. Rockets and capsules to change this are on their way, and many possible uses for this very powerful and very costly equipment has been debated for some time.

    All the while, in the place of human exploration of space has been the phenomenal success of the space science program — with its grand observatories like the Hubble (and soon the James Webb Space Telescope), unmanned mission such as Cassini (to Saturn) and Juno (to Jupiter) and New Horizons (to Pluto,) ground-breaking surveys of the exoplanet world by Kepler, and the now five years of Curiosity roving on Mars.

    All have been immensely popular with the public by any measure, and I like to think they helped people understand much better the world in which we live. But the missions are clearly less appealing to commercial, military and generally strategic forces that seem to want a very different kind of American space program.

    Our overall national space effort has always spent more on the military side than the civilian, and NASA has also obviously played a role that is both geopolitically and militarily important.

    But at its heart, NASA has for some time been about exploring and better understanding the planets and exoplanets and stars and galaxies of our universe (those Many Worlds,) and thereby enriching, enormously, I believe, life here on Earth.

    The cis-lunar vision of Bridenstine and others may fail to get off the drawing boards, rather like the Obama Administration’s plan to capture and pull an asteroid towards Earth where astronauts could learn how to live and work in deep space.

    But change is in the air, and the selection of Bridenstine is a pretty clear sign of how and where the winds are blowing.

    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 2:46 pm on August 17, 2017 Permalink | Reply
    Tags: , , , , Many Worlds, ,   

    From Many Worlds: “Of White Dwarfs, “Zombie” Stars and Supernovae Explosions” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-08-17
    Marc Kaufman

    1
    Artistic view of the aftermath of a supernova explosion, with an unexpected white dwarf remnant. These super-dense but no longer active stars are thought to play a key role in many supernovae explosion. (Copyright Russell Kightley)

    White dwarf stars, the remnant cores of low-mass stars that have exhausted all their nuclear fuel, are among the most dense objects in the sky.

    Their mass is comparable to that of the sun, while their volume is comparable to that of Earth. Very roughly, this means the average density of matter in a white dwarf would be on the order of 1,000,000 times greater than the average density of the sun.

    Thought to be the final evolutionary state of stars whose mass is not high enough to become a neutron star — a category that includes the sun and over 97% of the other stars in the Milky Way — they are dim objects first identified a century ago but only in the last decade the subject of broad study.

    In recent years the white dwarfs have become more and more closely associated with supernovae explosions, though the processes involved remained hotly debated. A team using the Hubble Space Telescope even captured before and after images of what is hypothesized to be an incomplete white dwarf supernova. What was left behind has been described by some as a “zombie star.”

    Now a team of astronomers led by Stephane Vennes of the Czech Academy of Sciences has detected another zombie white dwarf, LP-40-365 , that they put forward as a far-flung remnant of a long-ago supernova explosion. This is considered important and unusual because it would represent a first detection of such a remnant long after the supernova conflagration.

    This dynamic is well captured in an animation accompanying the Science paper that describes the possible remnant.

    A supernova — among the most powerful forces in the universe — occurs when there is a change in the core of a star. A change can occur in two different ways, with both resulting in a thermonuclear explosion.

    Type Ia supernova occurs at the end of a single star’s lifetime. As the star runs out of nuclear fuel, some of its mass flows into its core. Eventually, the core is so heavy that it cannot withstand its own gravitational force. The core collapses, which results in the giant explosion of a supernova. The sun is a single star, but it does not have enough mass to become a supernova.

    The second type takes place only in binary star systems. Binary stars are two stars that orbit the same point. One of the stars, a carbon-oxygen white dwarf, steals matter from its companion star. Eventually, the white dwarf accumulates too much matter. Having too much matter causes the star to explode, resulting in a supernova.

    Type Ia supernovae, which are the result of the complete destruction of the star in a thermonuclear explosion, have a fairly uniform brightness that makes them useful for cosmology. The light emitted by the supernova explosion can be, for a short while at least, as bright as the whole of the Milky Way.

    Recently, astronomers have discovered a related form of supernova, called Type Iax, which look like Type Ia, but are much fainter. Type Iax supernovae may be caused by the partial destruction of a white dwarf star in such an explosion. If that interpretation is correct, part of the white dwarf should survive as a leftover object.

    And that leftover object is precisely what Vennes et al claim to have found.

    They have identified LP 40-365 as an unusual white dwarf with a low mass, high velocity and strange composition of oxygen, sodium and magnesium – exactly as might be expected for the leftover star from a Type Iax event. Vennes describes the white dwarf remnant his team has detected as a “compact star,” and perhaps the first of its kind in terms of the elements it contains.

    The team calculate that the explosion must have occurred between five and 50 million years ago.

    2
    The two inset images show before-and-after images captured by NASA’s Hubble Space Telescope of Supernova 2012Z in the spiral galaxy NGC 1309, what some call a “zombie star.”. The white X at the top of the main image marks the location of the supernova in the galaxy. A supernova typically obliterates the exploding white dwarf, or dying star. In 2014, scientists found that this faint supernova may have left behind a surviving portion of the white dwarf star.(NASA,ESA)

    In an email exchange, Vennes told me that he has been studying the local white dwarf population for thirty years.

    “These compact, dead stars tell us a lot about the “old” Milky Way, how stars were born and how they died,” he wrote.

    “Tens of thousands of these white dwarfs have been catalogued over this past century, most of them in the last decade, but we keep an eye on outliers, objects that are out of the norm. We look for exceedingly large velocity, peculiar chemical composition or abnormal mass or radii.

    “The strange case of LP40-365 came unexpectedly, but this was a classic case of serendipity in astronomy. Out of hundreds of targets we observed at the telescope, this one was uniquely peculiar. Fortunately, theorists are very imaginative and the model we adopted to interpret the observed properties of this object were only recently published. Our research on this object was certainly inspired and directed by their theory.”

    Vennes says the team was surprised to learn that the white dwarf LP40-365 is relatively bright among its peers and that similar objects did not show up in large-scale surveys such as the Sloan Digital Sky Survey.

    “This fact has convinced us that many more similarly peculiar white dwarfs await discovery. We should search among fainter, more distant samples of white dwarfs,” he wrote.

    And that search can be done by the European Space Agency’s Gaia astrometric space telescope, with follow-up observations at large telescopes such as the European Southern Observatory’s Very Large Telescope and the Gemini observatory in Chile.

    ESA/GAIA satellite

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level


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

    “It is also likely that our adopted model involving a subluminous {faint} Type Ia supernova will be modified or even superseded by teams of theorists coming up with new ideas. But we remain confident that these new ideas would still involve a cataclysmic event on the scale of a supernova.”

    A supernova burns for only a short period of time, but it can tell scientists a lot about the universe.

    One kind of supernova has shown scientists that we live in an expanding universe, one that is growing at an ever increasing rate.

    Scientists also have determined that supernovas play a key role in distributing elements throughout the universe. When the star explodes, it shoots elements and debris into space. Many of the elements we find here on Earth are made in the core of stars.

    These elements travel on to form new stars, planets and everything else in the universe — making white dwarfs and supernovae essential to the process that ultimately led to life.

    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 9:53 am on August 11, 2017 Permalink | Reply
    Tags: , , , , , Many Worlds   

    From Many Worlds: “Primordial Asteroids, And The Stories They Are Telling” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-08-07
    Marc Kaufman

    1
    The main asteroid belt of our solar system — with almost two million asteroids a kilometer in diameter orbiting in the region between Mars and Jupiter. There are billions more that are smaller. New research has identified the “family” of a primordial asteroid or planetesimal, one of the oldest ever detected.

    Asteroid, we’ve long been told, started tiny in our protoplanetary disk and only very gradually became more massive through a process of accretion. They collected dust from the gas cloud that surrounded our new star, and then grew larger through collisions with other growing asteroids.

    But in recent years, a new school of thought has proposed a different scenario: that large clumps of dust and pebbles in the disk could experience gravitational collapse, a binding together of concentrated disk material.

    This process would produce a large asteroid (which is sometimes called a planetesimal) relatively quickly, without that long process of accretion. This theory would solve some of the known problems with the gradual accretion method, though it brings some problems of its own.

    Now research just published in the journal Science offers some potentially important support to the gravitational collapse model, while also describing the computational detection of a primordial family of asteroids some 4 billion years old.

    Led by Marco Delbo’, an astrophysicist at the University of the Côte d’Azur in Nice, France, the scientists have identified a previously unknown family of darkly colored asteroids that is “the oldest known family in the main belt,” their study concluded.

    The family was identified and grouped together by the unusual darkness (low albedo) of its asteroids’ reflective powers, a signature that the object has a high concentrations of carbon-based organic compounds. This family of asteroids was also less extensively heated — having formed when the sun radiated less energy — and contains more water, making them potential goldmines for understanding the makeup and processes of the early solar system.

    2
    Artist depiction of a dusty disc surrounding a red dwarf.artist rendering of a protoplanetary dust disk, from which asteroid, planetesimals and ultimately planets are formed. NASA/JPL-Caltech/T. Pyle (SSC)

    “They are from an original planetesimal and the location of these fragments tell us they are very, very old,” Delbo’ told me. “So old that the original object is older than the epoch when our giant planets moved to their current locations.” That would make this ancient asteroid family more than 4 billion years old, formed when the solar system was but 600 million years from inception.

    By adding up the masses of the members of the asteroid family, the researchers could also come up with a size for the original planetesimal that gave birth to the asteroid family — at least 35 kilometers wide at its inception.

    Some background:

    What is termed our “solar nebula” is thought to have been a disk-shaped cloud of gas and dust that remained after the formation of the sun. Just like a dancer that spins faster as she pulls in her arms, the cloud began to spin as it collapsed. Eventually, the cloud grew hotter and more dense in the center, with a disk of gas and dust surrounding it that was hot near the center but cool at the edges.

    Since these earliest days of the solar system, a vast collection of dust and later rocks of all shapes and sizes has been circling the sun, especially in the broad expanse of space between Mars and Jupiter. This is both the material from which planets were formed, and also leftover material from the formation of the solar system.

    There are many of these asteroids, or planetesimals, but they don’t carry much mass — all of them together roughly equaling that of our moon.

    There are some 130 known “families” of asteroids. The effort to understand the processes that created the asteroids has been enormously difficult because they have been broken and then broken again and again as they crash into each other.

    But that is changing thanks to this discovery of the new family of “dark” asteroids. Unlike the brighter, highly reflective asteroid families nearby, the population of dark asteroids’ orbits are more spread out, interpreted to mean that more time has passed since the asteroids formed

    Most asteroid families are thought to have formed about 1 billion years ago. By aggregating the sizes of the modern dark asteroids, researchers suggest their original planetesimals formed about 4 billion years ago, making this one of the oldest asteroid families in the main asteroid belt.

    The scientists also determined that the dark family’s original planetesimals were no smaller than about 25 miles across.

    This provides support for the gravitational collapse hypothesis, originated at Germany’s Max Planck Institute, by suggesting the oldest asteroids started out large, and then became smaller through collisions and other destructive forces happening in the ancient solar system.

    The earlier and more conventional theory had the asteroids starting small and getting gradually bigger. This difference in hypotheses has been a hot topic among planetary scientists for nearly a decade.

    3
    This image, taken by NASA’s Near Earth Asteroid Rendezvous mission in 2000, shows a close-up view of Eros, an asteroid with an orbit that takes it somewhat close to Earth. American and Japanese and European missions to study and scoop up material from asteroids are now on their way. The European Space Agency has also undertaken an asteroid landing mission and a joint NASA-ESA asteroid-ramming mission is under consideration. NASA/JHUAPL

    These findings are not based on telescope viewing and measuring; that was all done by NASA’s Wide-field Infrared Survey Explorer in 2011. The spacecraft took images of some 750 million objects, including millions of asteroids.

    Delbo’ and his team used computer models to search for groups of related asteroids spread within a V-shaped region. This V pattern is what one would expect from a single object that fragmented into pieces, and the wider the V-shape the older the objects.

    Their asteroid family features rocks averaging 7.15 miles in diameter, and are found across the entire inner part of the main asteroid belt. The family has 108 members and counting, with the largest of which the largest being asteroid 282 Clorinde, which is about 26 wide.

    “Each family member drifts away from the center of the family in a way that depends on its size, with small guys drifting faster and further than the larger guys,” Delbo said. “If you look for correlations of size and distance, you can see the shapes of old families.”

    But that wasn’t all.

    “By identifying all the families in the main belt, we can figure out which asteroids have been formed by collisions and which might be some of the original members of the asteroid belt,” said Southwest Research Institute astronomer Kevin Walsh, a coauthor of the Science article.

    “We identified all known families and their members and discovered a gigantic void in the main belt, populated by only a handful of asteroids. These relics must be part of the original asteroid belt. That is the real prize, to know what the main belt looked like just after it formed.”

    These primordial objects had to have formed differently from those belonging to the newer families. They were the original inhabitants and were present in the inner asteroid belt before anything else.

    ranging from 21 to around 93 miles across, their size matches up with predictions from theoretical models of how large original asteroids might have been 4 billion years ago, when they initially formed.

    In other words, their age and size supports the gravitational collapse theory of asteroid formation.

    5
    An artist’s concept depicts a distant hypothetical solar system, similar in age to our own. Looking inward from the system’s outer fringes, a ring of dusty debris can be seen, and within it, planets circling a star the size of our Sun. This debris is all that remains of the planet-forming disk from which the planets evolved. Planets are formed when dusty material in a large disk surrounding a young star clumps together. (NASA)

    To put these findings into a larger context, I asked Elizabeth Tasker, astrophyscist at the Japan Space Agency and the Earth-Life Science Institute in Tokyo, to explain further. She is the author of the soon-to-be released book, “The Planet Factory,” which deals extensively with these issues. First is her take on the logic of gravitational collapse:

    “In the gravitational collapse model, the pebbles and small boulders around 1m-ish in size concentrate in one region of the protoplanetary disk. This concentration initially happens because nothing is ever perfectly homogeneous, but it grows because having a group of rocks together helps mitigate the gas drag.

    This grows until eventually its combined mass is enough that their total gravity finally becomes a big enough force to bind them together into a planetesimal. This doesn’t happen until you have a serious chunk of mass, so the result is always a big planetesimal tens to hundred of kilometers across (about the size of Ceres). A smaller group of rocks wouldn’t have enough total mass to produce the gravitational force needed to collapse.”

    And now why the Delbo’ paper is important:

    “The formation of our own solar system is the key to understanding the properties of exoplanets around other stars. For example, if we truly want to find another habitable world, we need to understand how the Earth acquired and kept its oceans, developed a protective magnetic field and a sizeable moon, while Venus and Mars did not.

    “A problem we face is that the early planet-forming action happened 4.6 billion years ago. We can build models, but how do we tell which one is correct when this all happened so long ago?

    “Marco Delbo’ and his team have identified a holy grail; an observational signature that can be used to constrain the myriad of formation ideas we are imaginative enough to create.”

    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 11:42 am on July 13, 2017 Permalink | Reply
    Tags: , , , , Has America Really Lost It’s 'Lead in Space?', Many Worlds   

    From Many Worlds: “Has America Really Lost It’s ‘Lead in Space?’ “ 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-07-13
    Marc Kaufman

    1
    Vice President Mike Pence addresses NASA employees, Thursday, July 6, 2017, at the Vehicle Assembly Building at NASA’s Kennedy Space Center (KSC) in Cape Canaveral, Florida. The Vice President spoke following a tour that highlighted the public-private partnerships at KSC, as both NASA and commercial companies prepare to launch American astronauts in the years ahead. Pence spoke at length about human space exploration, but very little about NASA space science. (NASA/Aubrey Gemignani).

    I was moved to weigh in after reading Vice President Mike Pence’s comments last week down at the Kennedy Space Center — a speech that seemed to minimize NASA’s performance in recent years (decades?) and to propose a return to a kind of Manifest Destiny way of thinking in space.

    The speech did not appear to bode well for space science, which has dominated NASA news with many years of exploration into the history and working of the cosmos and solar system, the still little-understood domain of exoplanets, the search for life beyond Earth.

    Instead, the speech was very much about human space exploration, with an emphasis on “boots on the ground,” national security, and setting up colonies.

    “We will beat back any disadvantage that our lack of attention has placed and America will once again lead in space,” Pence said.

    “We will return our nation to the moon, we will go to Mars, and we will still go further to places that our children’s children can only imagine. We will maintain a constant presence in low-Earth orbit, and we’ll develop policies that will carry human space exploration across our solar system and ultimately into the vast expanses. As the president has said, ‘Space is,’ in his words, ‘the next great American frontier.’ And like the pioneers that came before us, we will settle that frontier with American leadership, American courage and American ingenuity.” (Transcript here.)

    That a new president will have a different kind of vision for NASA than his predecessors is hardly surprising. NASA may play little or no role in a presidential election, but the agency is a kind of treasure trove of high profile possibilities for any incoming administration.

    That the Trump administration wants to emphasize human space exploration is also no surprise. Other than flying up and back to construct and use the International Space Station, and then out to the Hubble Space Telescope for repairs, American astronauts have not been in space since the last Apollo mission in 1972. It should be said, however, that no other nation has sent astronauts beyond low Earth orbit, either, since then.

    Where I found the speech off-base was to talk down the many extraordinary discoveries in recent decades about our planet, the solar system, the galaxy and beyond made during NASA missions and made possible by cutting-edge NASA technology and innovations.

    In fact, many scientists, members of Congress and NASA followers would enthusiastically agree that the last few decades have been an absolute Golden Age in space discovery — all of it done without humans in space (except for those Hubble repairs.)

    To argue for a more muscular human space program does not have to come with a diminishing of the enormous space science advances of these more recent years; missions and discoveries that brought to Americans and the world spectacular images and understandings of Mars, of Jupiter and Saturn and their potentially habitable moons, of Pluto, of hot Jupiters, super-Earths and exoplanet habitable zones, and of deep, deep space and time made more comprehensible because of NASA grand observatories.

    To say that the United States has given up its “lead in space,” it seems to me, requires a worrisome dismissal of all this and much more.

    2
    Selfie of Curiosity rover on sedimentary rock deposited by water in Gale Crater on Mars. (NASA) [Interesting, where is an arm carrying the camera that took the selfie?]

    Let’s start on Mars. For the past 20 years, NASA has had one or more rovers exploring the planet. In all, the agency has successfully landed seven vehicles on the planet — which is the sum total of human machinery that has ever arrived in operational shape on the surface (unless you count the Soviet Mars 3 capsule which landed in 1971 and sent back information for 14 seconds before going silent.)

    One of the two rovers now on Mars — Curiosity — has established once and for all time that Mars was entirely habitable in its early life. It has drilled into the planet numerous times and has tested the samples for essential-for-life carbon organic compounds (which it found.) It also has detected clear evidence of long-ago and long-standing lakes and rivers. And it measured radiation levels at the surface over years to help determine how humans might one day survive there.

    I think it’s fair to say that Curiosity has advanced an understanding of the history and current realities of Mars more than any other mission, and perhaps more than all the others combined.

    Equally important, the almost two-thousand pound rover was delivered to the surface via a new landing technique called the “sky crane.” If your goal is to some day land a human on Mars, then learning how to deliver larger and larger payloads is essential because a capsule for astronauts would weigh something like 80,000 pounds.

    The European Space Agency, as well as the Russians and Chinese, have tried to send landers to Mars in recent years, but with no success.

    And as for Curiosity, it has been exploring Mars now for almost five years — well past its nominal mission lifetime.

    3
    This Cassini image of Saturn is the of 21 frames across 7 footprints, filtered in groups of red, green, and blue. The sequence was captured by Cassini over the course of 90-plus minutes on the morning of October 28th. Like many premier images from space, an individual — here Ian Regan — used the public access information and images provided by NASA of all its missions to produce the mosaic. (NASA/JPL-Caltech/Space Science Institute/Ian Regan).

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    NASA missions to Saturn and Jupiter have sent back images that are startling in their beauty and overflowing in their science. And they have found unexpected features that could some day lead to a discovery of extraterrestrial life in our solar system.

    The most surprising discovery was at Saturn’s moon Enceladus, which turns out to be spewing water vapor into space from its south pole region. This water contains, among other important compounds, those organic building blocks of life, as well as evidence that the plumes are generated by hydrothermal heating of the ocean under the surface of the moon.

    In other words, there is a global ocean on Enceladus and at the bottom of it water and hot rock are in contact and are reacting in a way that, on Earth at least, would provide an environment suitable for life. And then the moon is spitting out the water to make it quite possible to study that water vapor and whatever might be in it.

    If the last decades are a guide, up-close study of these icy moons is a challenge and opportunity that the United States alone — sometimes in collaboration with European partners — has shown the ability and appetite to embrace make happen.

    4
    NASA’s Cassini spacecraft completed its deepest-ever dive through the icy plume of Enceladus on Oct. 28, 2015. (NASA/JPL-Caltech).

    The plumes were investigated and even traversed by the Cassini spacecraft, which is a joint NASA-ESA mission [with ASI]. The primary ESA contribution was the Huygens probe that descended to Titan in 2005. To people in the space science community, these kind of collaborations — generally with European space agencies — allow for more complex missions and good international relations.

    Plumes of water vapor have also been tentatively discovered identified on Jupiter’s moon, Europa. The data for the discovery came mostly from the Hubble Space Telescope, and is already a part of the previously approved NASA future. The Europa Clipper is scheduled to launch in the 2020s, to orbit the moon and intensively examine the solar system world believed most likely to contain life.

    NASA/Europa Clipper

    The plumes would be coming from another large global ocean under a thick shell of ice, a body of water understood to be much older and much bigger than that of Enceladus. Clearly, having some of that H2O available for exploration without going through the thick ice shell would be an enormous obstacle eraser.

    A follow-up Europa lander mission has been studied and got favorable reviews from a NASA panel, but was not funded by the Trump Administration. Several follow-up Enceladus life-detection missions are currently under review.

    5
    This very high resolution mosaic image of the Pillars of Creation was taken by the Hubble Space Telescope in 2014 and is a reprise of the iconic image first taken in 1995. The pillars are part of a nebula some 6,500-7000 light-years from Earth, and are immense clouds of gas and dust where stars are born. (NASA).

    NASA/ESA Hubble Telescope

    .

    I think one could make a strong case that the Hubble Space Telescope has been the most transformative, productive and admired piece of space technology ever made.

    For more than two decades now it has been the workhorse of the astrophysics, cosmology and exoplanet communities, and has arguably produced more world-class stunning images than Picasso. In terms of exploring the cosmos and illustrating some of what’s out there, it has no competition.

    There is little point to describing its specific accomplishments in terms of discovery because they are so many. Suffice it to say that a collection of published science papers using Hubble data would be very, very thick.

    And because of past NASA, White House and congressional commitment to space science, the over-budget and long behind-schedule James Webb Space Telescope is now on target to launch late next year.

    NASA/ESA/CSA Webb Telescope annotated

    The Webb will potentially be as revelatory as the Hubble, or even more so in terms of understanding the early era of the universe, the nature and origin of ubiquitous dark matter, and the composition of exoplanets.

    Preliminary planning for the great observatory for the 2030s is underway now, and nobody knows whether funding for something as ambitious will be available.

    NASA/WFIRST

    7
    The era of directly imaging exoplanets has only just begun, but the science and viewing pleasures to come are appealingly apparent. This evocative movie of four planets more massive than Jupiter orbiting the young star HR 8799 is a composite of sorts, including images taken over seven years at the W.M. Keck observatory in Hawaii. (Jason Wang/University of California, Berkeley and Christian Marois, National Research Council of Canada’s Herzberg Institute of Astrophysics. )


    Keck Observatory, Mauna Kea, Hawaii, USA

    Many of the early exoplanet discoveries were made by astrophysicists at ground-based observatories, and were made by both American, European and Canadian scientists. NASA’s Spitzer Space Telescope and others played a kind of supporting role for the agency, but that all changed with the launch of NASA’s Kepler Space Telescope.

    NASA/Spitzer Telescope

    .

    NASA/Kepler Telescope

    From 2009 to today, the Kepler has identified more than 4,000 exoplanet candidates with more than 2,400 confirmed planets, many of which are rocky like Earth. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.

    The census provided by Kepler, which looked fixedly at only one small part of the deep sky for four years until mechanical, led to the consensus conclusion that the Milky Way alone is home to billions of planets and that many of them are rocky and in the habitable zone of their host stars.

    In other words, Kepler made enormous progress in defining the population of exoplanets likely to exist out there — a wild menagerie of objects very different from what might have been expected, and in systems very different as well.

    Two additional NASA observatories designed to detect and study exoplanets are scheduled to launch in the next decade.

    Given the number of references to our moon in Pence’s Kennedy Space Station speech — and the enormous costs of the also often referenced humans-to-Mars idea — my bet is that moon landings and perhaps a “colony” will be the Administration’s human space exploration project of choice.

    I say this because it is achievable, with NASA rockets and capsules under construction and the fast-growing capabilities of commercial space competitors. We have, after all, proven that astronauts can land and survive on the moon, and a return there would be much less expensive than sending a human to Mars and back. (I’m also skeptical that such a trip to Mars will be technically feasible any time in the foreseeable future, though I know that others strongly disagree.)

    As readers of Many Worlds may remember, I’m a fan of a human spaceflight project championed by former astronaut and head of NASA’s Science Directorate John Grunsfeld to assemble a huge observatory in space designed to seriously look for life around distant stars. This plan is innovative, would give NASA and astronauts an opportunity learn how to live and work in deep space, and would provide another science gem.

    But here is why I think a moon colony is going to be the choice: Russia, China and the Europeans have all announced tentative plans to build moon colonies in the next decade or two. So for primarily strategic, competitive and national security reasons, it seems likely that this kind of “new frontier” is what the administration has in mind.

    After all, Pence also said in his speech at the KSC that “Under President Donald Trump, American security will be as dominant in the heavens as we are here on Earth.”

    Setting up an American moon colony would be very costly in dollars, time and focus, but it’s not necessarily a bad thing. Given that a pie can be sliced just so many ways, however, it’s pretty clear that a major moon colony project would end up taking a significant amount of funding away from space science missions.

    Returning to the moon and even setting up a colony is not, however, an example of American leadership. Rather, it would constitute a decision for the United States and NASA to, in effect, follow the pack.

    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 2:48 pm on July 6, 2017 Permalink | Reply
    Tags: , , , , Certain Big, Charged Molecules Are Universal to Life. Can They Help Detect It Elsewhere in the Solar System?, , Many Worlds   

    From Many Worlds: “Certain Big, Charged Molecules Are Universal to Life. Can They Help Detect It Elsewhere in the Solar System?” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-07-06
    Marc Kaufman

    1
    NASA’s Cassini spacecraft completed its deepest-ever dive through the icy plume of Enceladus on Oct. 28, 2015. The spacecraft did not have instruments that could detect life, but missions competing for NASA New Frontiers funding will — raising the thorny question of how life might be detected. (NASA/JPL-Caltech)

    As NASA inches closer to launching new missions to the Solar System’s outer moons in search of life, scientists are renewing their focus on developing a set of universal characteristics of life that can be measured.

    There is much debate about what might be considered a clear sign of life, in part, because there are so many definitions separating the animate from the inanimate.

    NASA’s prospective missions to promising spots on Europa, Enceladus and Titan have their individual approaches to detecting life, but one respected voice in the field says there is a better way that’s far less prone to false positives.

    Noted chemist and astrobiologist Steven Benner says life’s signature is not necessarily found in the presence of particular elements and compounds, nor in its effects on the surrounding environment, and is certainly not something visible to the naked eye (or even a sophisticated camera).

    Rather, life can be viewed as a structure, a molecular backbone that Benner and his group, Foundation for Applied Molecular Evolution (FfAME), have identified as the common inheritance of all living things. Its central function is to enable what origin-of-life scientists generally see as an essential dynamic in the onset of life and its increased complexity and spread: Darwinian evolution via transfer of information, mutation and the transfer of those mutations.

    “What we’re looking for is a universal molecular bio-signature, and it does exist in water,” says Benner. “You want a genetic molecule that can change physical conditions without changing physical properties — like DNA and RNA can do.”

    2
    Steven Benner, director of the Foundation for Applied Molecular Evolution or FfAME. (SETI)

    Looking for DNA or RNA on an icy moon, or elsewhere would presuppose life like our own — and life that has already done quite a bit of evolving.

    A more general approach is to find a linear polymer (a large molecule, or macromolecule, composed of many repeated subunits, of which DNA and RNA are types) with an electrical charge. That, he said, is a structure that is universal to life, and it can be detected.

    As described in a recent paper that Benner’s group published in the journal Astrobiology: “the only molecular systems able to support Darwinian information are linear polymers that have a repeating backbone charge. These are called ‘polyelectrolytes.’

    “These data suggest that polyelectrolytes will be the genetic molecules in all life, no matter what its origin and no matter what the direction or tempo of its natural history, as long as it lives in water.”

    Through years of experimentation, Benner and others have found that electric charges in these crucial polymers, or “backbones,” of life have to repeat. If they are a mixture of positive and negative charges, then the ability to pass on changing information without the structure itself changing is lost.

    And as a result, Benner says, detecting these charged, linear and repeating large molecules is potentially quite possible on Europa or Enceladus or wherever water is found. All you have to do is expose those charged and repeating molecular structures to an instrument with the opposite charge and measure the reaction.

    3
    Polyelectrolytes are long-chain, molecular semiconductors, whose backbones contain electrons. The structure and composition of the polyelectrolytes confers an ability to transfer electric charge and the energy of electronic excited states over distance. (Azyner Group, UCSC)

    James Green, director of NASA’s Planetary Sciences division, sees values in this approach.

    “Benner’s polyelectrolyte study is fascinating to me since it provides our scientists another critical discussion point about finding life with some small number of experiments,” he says.

    “Finding life is very high bar to cross; it has to metabolize, reproduce, and evolve — all of which I can’t develop an experiment to measure on another planet or moon. If it doesn’t talk or move in front of the camera we are left with developing a very challenging set of instruments that can only measure attributes. So polyelectrolytes are one more to consider.”

    Benner has been describing his universal molecular bio-signature to leaders of the groups competing for New Frontiers missions, which fill the gap between smaller Discovery missions and large flagship planetary missions. It’s taken a while but due to his efforts over several years, he notes that interest seems to be growing in incorporating his findings.

    4
    Astrobiologist Chris McKay at NASA’s Ames Research Center. (IDG News Service)

    In particular, Chris McKay, a prominent astrobiologist at NASA’s Ames Research Center and a member of one of the New Frontiers Enceladus proposal teams, says he thinks there is merit to Benner’s idea.

    “The really interesting aspect of this suggestion is that new technologies are now available for sequencing DNA that can be generalized to read any linear molecule,” McKay writes in an email.

    In other words, they can detect any polyelectrolytes.

    Other teams are confident that their own kinds of life detection instruments can do the job. Morgan Cable, deputy project scientist of the Enceladus Life Finder proposal, she says her team has great confidence in its four-pronged approach. A motto of the mission on some of its written material is: “If Encedadus has life, we will find it.”

    The package includes instruments like mass spectrometers able to detect large molecules associated with life; measurements of energy gradients that allow life to be nourished; detection of isotopic signatures associated with life; and identification of long carbon chains that serve as membranes to house the components of a cell.

    “Not one but all four indicators have to point to life to make a potential detection,” Cable says.

    NASA is winnowing down 12 proposals by late this year, so, Benner’s ideas could play a role later in the process as well. NASA’s goal is to select its next New Frontiers mission in about two years, with launch in the mid-2020s.

    The Europa Clipper orbiter mission is tentatively scheduled to launch in 2022, but its companion lander has been scrubbed for now by the Trump administration.

    Nonetheless, NASA put out a call last month for instruments that might one day sample the ice of Europa. Benner is once more hoping that his theory of polyelectrolytes as the key to identifying life in water or ice will be considered and embraced.

    5
    These composite images show a suspected plume of material erupting two years apart from the same location on Jupiter’s icy moon Europa. Both plumes, photographed in UV light by Hubble, were seen in silhouette as the moon passed in front of Jupiter. Europa is a major focus of the search for life beyond Earth. (NASA/ESA/STScI/USGS)

    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 4:21 pm on June 24, 2017 Permalink | Reply
    Tags: , , , , , Extremeophiles, Many Worlds, MatISSE - Maturation of Instruments for Solar System Exploration, Oxford Nanopore, , SETG - The Search for Extraterrestrial Genomes   

    From Many Worlds: “In Search of Panspermia (and Life on Icy Moons)” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-06-23
    Marc Kaufman

    1
    Early Earth, like early Mars and no doubt many other planets, was bombarded by meteorites and comets. Could they have arrived “living” microbes inside them?

    When scientists approach the question of how life began on Earth, or elsewhere, their efforts generally involve attempts to understand how non-biological molecules bonded, became increasingly complex, and eventually reached the point where they could replicate or could use sources of energy to make things happen. Ultimately, of course, life needed both.

    Researchers have been working for some time to understand this very long and winding process, and some have sought to make synthetic life out of selected components and energy. Some startling progress has been made in both of these endeavors, but many unexplained mysteries remain at the heart of the processes. And nobody is expecting the origin of life on Earth (or elsewhere) to be fully understood anytime soon.

    To further complicate the picture, the history of early Earth is one of extreme heat caused by meteorite bombardment and, most important, the enormous impact some 4.5 billion years of the Mars-sized planet that became our moon. As a result, many early Earth researchers think the planet was uninhabitable until about 4 billion years ago.

    Yet some argue that signs of Earth life 3.8 billion years ago have been detected in the rock record, and lifeforms were certainly present 3.5 billion years ago. Considering the painfully slow pace of early evolution — the planet, after all, supported only single-cell life for several billion years before multicellular life emerged — some researchers are skeptical about the likelihood of DNA-based life evolving in the relatively short window between when Earth became cool enough to support life and the earliest evidence of actual life.

    2
    A DNA helix animation. Life on Earth is based on DNA, and some researchers have been working on ways to determine whether DNA life also exists on Mars or elsewhere in the solar system.

    So what else, from a scientific as opposed to a religious perspective, might have set into motion the process that made life out of non-life?

    One long considered yet generally quickly dismissed answer is getting new attention and a little more respect. It invokes panspermia, the sharing of life via meteorites from one planet to another, or delivery by comet.

    In this context, the question generally raised is whether Earth might have been seeded by early Martian life (if it existed). Mars, it is becoming increasingly accepted, was probably more habitable in its early period than Earth. But panspermia inherently could go the other way as well, or possibly even between solar systems.

    A team of prominent scientists at MIT and Harvard are sufficiently convinced in the plausibility of panspermia that they have spent a decade, and a fair amount of NASA and other funding, to design and produce an instrument that can be sent to Mars and potentially detect DNA or more primitive RNA.

    In other words, life not only similar to that on Earth, but actually delivered long ago from Earth. It’s called the The Search for Extraterrestrial Genomes, or SETG.

    Gary Ruvkun is one of those researchers, a pioneering molecular biologist at Massachusetts General Hospital and professor of genetics at Harvard Medical School.

    I heard him speaking recently at a Space Sciences Board workshop on biosignatures, where he described the real (if slim) possibility that DNA or RNA-based life exists now on Mars, and the instrument that the SETG group is developing to detect it should it be there.

    3
    Did meteorites spread life between planets, and maybe even solar systems? Some pretty distinguished people think that it may well have happened. This illustration is an artist’s rendering of the comet Siding Spring approaching Mars in 2015. (NASA)

    The logic of panspermia — or perhaps “dispermia” if between but two planets — is pretty straight-forward, though with some significant question marks. Both Earth and Mars, it is well known, were pummeled by incoming meteorites in their earlier epochs, and those impacts are known to have sufficient force to send rock from the crash site into orbit.

    Mars meteorites have been found on Earth, and Earth meteorites no doubt have landed on Mars. Ruvkun said that recent work on the capacity of dormant microbes to survive the long, frigid and irradiated trip from planet to planet has been increasingly supportive.

    “Earth is filled with life in every nook and cranny, and that life is wildly diverse,” he told the workshop. “So if you’re looking for life on Mars, surely the first thing to look for is life like we find on Earth. Frankly, it would be kind of stupid not to.”

    The instrument being developed by the group, which is led by Ruvkun and Maria Zuber, MIT vice president for research and head of the Department of Earth, Atmospheric and Planetary Sciences. It would potentially be part of a lander or rover science package and would search DNA or RNA, using techniques based on the exploding knowledge of earthly genomics.

    The job is made easier, Ruvkun said, by the fact that the basic structure of DNA is the same throughout biology. What’s more, he said, there about 400 specific genes sequences “that make up the core of biology — they’re found in everything from extremeophiles and bacteria to worms and humans.”

    Those ubiquitous gene sequences, he said, were present more than 3 billion years ago in seemingly primitive lifeforms that were, in fact, not primitive at all. Rather, they had perfected some genetic pathways that were so good that they still used by most everything alive today.

    And how was it that these sophisticated life processes emerged not all that long (in astronomical or geological terms) after Earth cooled enough to be habitable? “Either life developed here super-fast or it came full-on as DNA life from afar,” Ruvkun said. It’s pretty clear which option he supports.

    Ruvkun said that the rest of the SETG team sees that kind of inter-planetary transfer — to Mars and from Mars — as entirely plausible, and that he takes panspermia a step forward. He thinks it’s possible, though certainly not likely nor remotely provable today, that life has been around in the cosmos for as long as 10 billion years, jumping from one solar system and planet to another. Not likely, but at idea worth entertaining.

    4
    A state-of-the-art instrument for reading DNA sequences in the field. The MIT/Harvard team is working with the company that makes it, and several others, on refining how it would do that kind of sequencing of live DNA on Mars. The extremely high-tech thumb drive weighs about 3 ounces. (Oxford Nanopore)

    Maria Zuber of MIT, who was the PI for the recent NASA GRAIL mission to the moon, has been part of the SETG team since near its inception, and MIT research scientist Christopher Carr is the project manager. Zuber said it was a rather low-profile effort at the start, but over the years has attracted many students and has won NASA funding three times including the currently running Maturation of Instruments for Solar System Exploration (MatISSE) grant.

    “I have made my career out of doing simple experiments. if want to look for life beyond earth helps to know what you’re looking for.

    “We happen to know what life on Earth is like– DNA based or possibly RNA-based as Gary is looking for as well. The point is that we know what to look for. There are so many possibilities of what life beyond Earth could be like that we might as well test the hypothesis that it, also, is DNA based. It’s a low probability result, but potentially very high value.”

    DNA sequencing instruments like the one her team is developing are taken to the field regularly by thousands of researchers, including some working with with SETG. The technology has advanced so quickly that they can pick up a sample in a marsh or desert or any extreme locale and on the spot determine what DNA is present. That’s quite a change from the pain-staking sequencing done painstakingly by graduate students not that long ago.

    Panspermia, Zuber acknowledged, is a rather improbable idea. But when nature is concerned, she said “I’m reticent to say anything is impossible. After all, the universe is made up of the same elements as those on Earth, and so there’s a basic commonality.”

    Zuber said the instrument was not ready to compete for a spot on the 2020 mission to Mars, but she expects to have a sufficiently developed one ready to compete for a spot on the next Mars mission. Or perhaps on missions to Europa or the plumes of Enceladus.

    The possibility of life skipping from planet to planet clearly fascinates both scientists and the public. You may recall the excitement in the mid 1990s over the Martian meteorite ALH84001, which NASA researchers concluded contained remnants of Martian life. (That claim has since been largely refuted.)

    Of the roughly 61,000 meteorites found on Earth, only 134 were deemed to be Martian as of two years ago. But how many have sunk into oceans or lakes, or been lost in the omnipresence of life on Earth? Not surprisingly, the two spots that have yielded the most meteorites from Mars are Antarctica and the deserts of north Africa.

    And when thinking of panspermia, it’s worthwhile to consider the enormous amount of money and time put into keeping Earthly microbes from inadvertently hitching a ride to Mars or other planets and moons as part of a NASA mission.

    The NASA office of planetary protection has the goal of ensuring, as much as possible, that other celestial bodies don’t get contaminated with our biology. Inherent in that concern is the conclusion that our microbes could survive in deep space, could survive the scalding entry to another planet, and could possibly survive on the planet’s surface today. In other words, that panspermia (or dispermia) is in some circumstances possible.

    Testing whether a spacecraft has brought Earth life to Mars is actually another role that the SETG instrument could play. If a sample tested on Mars comes back with a DNA signature result exactly like one on Earth–rather one that might have come initially from Earth and then evolved over billions of years– then scientists will know that particular bit of biology was indeed a stowaway from Earth.

    Rather like how a very hardy microbe inside a meteorite might have possibly traveled long ago.

    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 7:08 am on June 2, 2017 Permalink | Reply
    Tags: , , , , , Many Worlds, , Nobel laureate Jack Szostak, Nobel Laureate Jack Szostak: Exoplanets Gave The Origin of Life Field a Huge Boost   

    From Many Worlds: “Nobel Laureate Jack Szostak: Exoplanets Gave The Origin of Life Field a Huge Boost” 

    NASA NExSS bloc

    NASA NExSS

    Many Words icon

    Many Worlds

    2017-06-02
    Marc Kaufman

    1
    Jack Szostak, Nobel laureate and pioneering researcher in the origin-of-life field, was the featured speaker at a workshop this week at the Earth-Life Science Institute (ELSI) in Tokyo. One goal of his Harvard lab is to answer this once seemingly impossible question: was the origin of life on Earth essentially straight-forward and “easy,” or was it enormously “hard” and consequently rare in the universe. (Nerissa Escandar)

    Sometimes tectonic shifts in scientific disciplines occur because of discoveries and advances in the field. But sometimes they occur for reasons entirely outside the field itself. Such appears to be case with origins-of-life studies.

    Nobel laureate Jack Szostak was recently in Tokyo to participate in a workshop at the Earth-Life Science Institute (ELSI) on “Reconstructing the Phenomenon of Life To Retrace the Emergence of Life.”

    The talks were technical and often cutting-edge, but the backstory that Szostak tells of why he and so many other top scientists are now in the origins of life field was especially intriguing and illuminating in terms of how science progresses.

    Those ground-shifting discoveries did not involve traditional origin-of-life questions of chemical transformations and pathways. They involved exoplanets.

    “Because of the discovery of all those exoplanets, astronomy has been transformed along with many other fields,” Szostak said after the workshop.

    “We now know there’s a large range of planetary environments out there, and that has stimulated a huge amount of interest in where else in the universe might there be life. Is it just here? We know for sure that lots of environments could support life and we also would like to know: do they?

    “This has stimulated much more laboratory-based work to try to address the origins question. What’s really important is for us to know whether the transition from chemistry to biology is easy and can happen frequently and anywhere, or are there one or many difficult steps that make life potentially very rare?”

    In other words, the explosion in exoplanet science has led directly to an invigorated scientific effort to better understand that road from a pre-biotic Earth to a biological Earth — with chemistry that allows compounds to replicate, to change, to surround themselves in cell walls, and to grow ever more complex.

    With today’s increased pace of research, Szostak said, the chances of finding some solid answers have been growing. In fact, he’s quite optimistic that an answer will ultimately be forthcoming to the question of how life began on Earth.

    “The field is making real progress in understanding the pathway from pre-biotic chemistry to the earliest life,” Szostak told. “We think this is a difficult but solvable problem.”

    And any solution would inevitably shed light on both the potential make-up and prevalence of extraterrestrial life.

    2
    This artist’s concept depicts select planetary discoveries made to date by NASA’s Kepler space telescope. (NASA/W. Stenzel)

    NASA/Kepler Telescope

    Whether it’s ultimately solvable or not, that pathway from non-life to life would appear to be nothing if not winding and complex. And since it involves trying to understand something that happened some 4 billion years ago, the field has had its share of fits and starts.

    It is no trivial fact that probably the biggest advance in modern origin-of-life science — the renown Miller-Urey experiment that produced important-for-life amino acids out of a sparked test tube filled with gases then believed to be prevalent on early Earth — took place more than 60 years ago.

    Much has changed since then, including an understanding that the gases used by Miller and Urey most likely did not reflect the early Earth atmosphere. But no breakthrough has been so dramatic and paradigm shifting since Miller-Urey. Scientists have toiled instead in the challenging terrain of how and why a vast array of chemicals associated with life just might be the ones crucial to the enterprise.

    But what’s new, Szostak said, is that the chemicals central to the pathway are much better understood today. So, too, are the mechanisms that help turn non-living compounds into self-replicating complex compounds, the process through which protective yet fragile cell walls can be formed, and the earliest dynamics involved in the essential task of collecting energy for a self-replicating chemical system to survive.

    2
    The simple protocells that may have enabled life to develop four billion years ago consist of only genetic material surrounded by a fatty acid membrane. This pared down version of a cell—which has not yet been completely recreated in a laboratory—is thought to have been able to grow, replicate, and evolve. (Howard Hughes Medical Institute)

    This search for a pathway is a major international undertaking; a collective effort involving many labs where obstacles to understanding the origin-of-life process are being overcome one by one.

    Here’s an example from Szostak: The early RNA replicators needed the element magnesium to do their copying. Yet magnesium destroyed the cell membranes needed to protect the RNA.

    A possible solution was to find potential acids to bond with magnesium and protect the membranes, while still allowing the element to be available for RNA chemistry. His team found that citric acid, or citrate, worked well when added to the cells. Problem solved, in the lab at least.

    The Szostak lab at Harvard University and the Howard Hughes Medical Institute has focused on creating “protocells” that are engineered by researchers yet can help explain how origin-of-life processes may have taken place on the early Earth.

    6

    Their focus, Szostak said, is on “what happens when we have the right molecules and how do they get together to form a cell that can grow and divide.”

    It remains a work in progress, but Szostak said much has been accomplished. Protocells have been engineered with the ability to replicate, to divide, to metabolize food for energy and to form and maintain a protective membrane.

    The perhaps ultimate goal is to develop a protocell with with the potential for Darwinian evolution. Were that to be achieved, then an essentially full system would have been created.

    3
    How did something alive emerge from a non-living world. It’s a question as old as humanity, but may in time prove to be solvable. Here blue-green algae in Morning Glory Pool, Yellowstone National Park, Wyoming.

    Just as the discovery of a menagerie of exoplanets jump-started the origin of life field, it also changed forever its way of doing business.

    No longer was the field the singular realm of chemists, but began to take in geochemists, planetary scientists, evolutionary biologists, atmospheric scientists and even astronomers (one of whom works in Szostak’s lab.)

    “A lot of labs are focused on different points in the process,” he said. “And because origins are now viewed as a process, that means you need to know how planets are formed and what happens on the planetary surface and in the atmospheres when they’re young.

    “Then there’s the question of essential volatiles (such as nitrogen, water, carbon dioxide, ammonia, hydrogen, methane and sulfur dioxide); when do they come in and are they too much or not enough.”

    These were definitely not issues of importance to Stanley Miller and Harold Urey when they sought to make building blocks of life from some common gases and an electrical charge.

    But seeing the origin of life question as a long pathway as opposed to a singular event leaves some researchers cold. With so many steps needed, and with the precisely right catalysts and purified compounds often essential to allow the next step take place, they argue that these pathways produced in a chemistry lab are unlikely to have anything to do with what actually happened on Earth.

    Szostak disagrees, strongly. “That just not true. The laws of chemistry haven’t changed since early Earth, and what we’re trying to understand is the fundamental chemistry of these compounds associated with life so we can work out plausible pathways.”

    If and when a plausible chemical pathway is established, Szostak said, it would then be time to turn the scientific process around and see if there is a possible model for the presence of the needed pathway ingredients on early Earth.

    And that involves the knowledge of geochemists, researchers expert in photochemistry and planetary scientists who have insight into what conditions were like at a particular time.

    4
    Szostak and David Deamer, an evolutionary biologist at the University of California, Santa Cruz, at the ELSI origins workshop.

    Deamer supports the view that life on Earth may well have begun in and around hydrothermal springs on land. That’s where essential compounds could concentrate, where energy was present and organic compounds on interstellar dust could have landed, as they do today. (Nerissa Escandar)

    Given the work that Szostak, his group and others have done to understand possible pathways that lead from simple starting materials to life, the inevitable question is whether there was but one pathway or many.

    Szostak is of the school that there may well have been numerous pathways that resulted in life, although only one seems to have won out. He bases his view, in part at least, on a common experience in his lab. He and his colleagues can bang their collective heads together for what seems forever on a hard problem only to later find there was not one or two but potentially many answers to it.

    An intriguing implication of this “many pathways” hypothesis is that it would seemingly increase the possibility of life starting beyond Earth. The underlying logic of Szostak’s approach is to find how chemicals can interact to form life-like and then more complex living systems within particular environments. And those varied environments could be on early Earth or on a planet or moon far away.

    “All of this looked very, very hard at the start, trying to identify the pathways that could lead to life. And sure, there are gaps remaining in our understanding. But we’ve solved a lot of problems and the remaining big problems are a rather small number. So I’m optimistic we’ll find the way.”

    “And when we get discouraged about our progress I think, you know, life did get started here. And actually it must quite simple. We’re just not smart enough to see the answer right away.

    “But in the end it generally turns out to be simple and you wonder 20 years later, why didn’t we think of that before?”

    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 10:09 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 .

    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 11:22 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 .

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    About Many Worlds

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

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

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

    About NExSS

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

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

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

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

     
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