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  • richardmitnick 8:26 am on October 7, 2015 Permalink | Reply
    Tags: , astrobio.net, Astrobiology, , Plant life   

    From astrobio.net: “Ancient alga knew how to survive on land before it left water & evolved into first plant” 

    Astrobiology Magazine

    Astrobiology Magazine

    Closterium strigosum is one of the green algae the scientists analyzed. Credit: Michael Melkonian

    A team of scientists led by Dr Pierre-Marc Delaux (John Innes Centre / University of Wisconsin, Madison) has solved a long-running mystery about the first stages of plant life on earth.

    The team of scientists from the John Innes Centre, the University of Wisconsin – Madison and other international collaborators, has discovered how an ancient alga was able to inhabit land, before it went on to evolve into the world’s first plant and colonise the earth.

    Up until now it had been assumed that the alga evolved the capability to source essential nutrients for its survival after it arrived on land by forming a close association with a beneficial fungi called arbuscular mycorrhiza (AM), which still exists today and which helps plant roots obtain nutrients and water from soil in exchange for carbon.

    The previous discovery of 450 million year old fossilised spores similar to the spores of the AM fungi suggests this fungi would have been present in the environment encountered by the first land plants. Remnants of prehistoric fungi have also been found inside the cells of the oldest plant macro-fossils, reinforcing this idea.

    However, scientists were not clear how the algal ancestor of land plants could have survived long enough to mediate a quid pro quo arrangement with a fungi. This new finding points to the alga developing this crucial capability while still living in the earth’s oceans!

    Dr Delaux and colleagues analysed DNA and RNA of some of the earliest known land plants and green algae and found evidence that their shared algal ancestor living in the Earth’s waters already possessed the set of genes, or symbiotic pathways, it needed to detect and interact with the beneficial AM fungi.

    The team of scientists believes this capability was pivotal in enabling the alga to survive out of the water and to colonise the earth. By working with the fungi to find sustenance, the alga was able to buy time to adapt and evolve in a very different and seemingly infertile environment.

    Dr Delaux said: “At some point 450 million years ago, alga from the earth’s waters splashed up on to barren land. Somehow it survived and took root, a watershed moment that kick-started the evolution of life on earth. Our discovery shows for the first time that the alga already knew how to survive on land while it was still in the water. Without the development of this pre-adapted capability in alga, the earth could be a very different place today.

    “This finding has filled a gap in our collective knowledge about the origins of life on earth. None of this would have been possible without the dedication of a world-wide team of scientists including a tremendous contribution from the 1KP initiative led by Gane KS Wong .”

    Professor Jean-Michel Ané, from the University of Wisconsin said: “The surprise was finding the mechanisms in algae which allow plants to interact with symbiotic fungi. Nobody has studied beneficial associations in these algae.”

    See the full article here .

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  • richardmitnick 6:02 pm on October 1, 2015 Permalink | Reply
    Tags: Astrobiology, , , , , U Kansas   

    From Kansas: “Scientists refine hunt for Mars life by analyzing rock samples in Western U.S” 

    U Kansas bloc

    University of Kansas

    LAWRENCE — The search for life beyond Earth is one of the grandest endeavors in the history of humankind — a quest that could transform our understanding of our universe both scientifically and spiritually.

    Petrographic thin section made from core sample. This 30 micron thin slice of rock allows a view of the types of features thought to be microbial. Here, the blue layers are an epoxy added in to see void-space in the rock, and the grey is sediment. The morphology of the orange-brown layers are suggestive of microbial activity, such as they way they roll over themselves in the bottom left and smoothly drape over the triangular feature. This type of deposition demonstrates that the sediment had to have a degree of cohesive stickiness, such as that provided by the presence of microbial mats.

    With news coming this week that NASA has confirmed the presence of flowing saltwater on the surface of Mars, the hunt for life on the Red Planet has new momentum.

    “One of the many reasons this is exciting is that life as we currently know it requires water,” said Alison Olcott-Marshall, assistant professor of geology at the University of Kansas. “So the fact that it’s present at Mars means that the most basic and universal requirement for life was fulfilled.”

    In the journal Astrobiology, Olcott-Marshall recently has published an analysis of Eocene rocks found in the Green River Formation, a lake system extending over parts of Colorado, Utah and Wyoming.

    Marshall and co-author Nicholas A. Cestari, a masters student in her lab, found these Green River rocks have features that visually indicate the presence of life, and they argue that probes to Mars should identify similar indicators on that planet and double-check them through chemical analysis.

    “Once something is launched into space, it becomes much harder to do tweaks — not impossible, but much, much harder,” Olcott-Marshall said. “Scientists are still debating the results of some of the life-detection experiments that flew to Mars on the Viking Missions in the late ’70s, in a large part because of how the experiments were designed. Looking at Earth-based analogs lets us get some of these bumps smoothed out here on Earth, when we can revise, replicate and re-run experiments easily.”

    Petrographic thin section made from core sample. This 30 micron thin slice of rock allows a view of the types of features thought to be microbial, such as the layers that fold over themselves in the middle of the sample marked 2534.8’. This demonstrates that the sediment had to have a degree of cohesive stickiness, such as that provided by the presence of microbial mats.

    The researchers examined cored samples of rock from 50 million years ago that included sections of “microbial mats.”

    “Microbial mats are essentially the microbial world’s version of apartment buildings — they are layered communities of microbes, and each layer represents a different metabolic strategy,” Olcott-Marshall said. “Generally, the photosynthetic microbes are at the top, and then every successive layer makes use of the waste products of the level above. Thus, not only does a microbial mat contain a great deal of biology, but a great number of chemicals, pigments and metabolic products are made, which means lots of potential biosignatures.”

    At times during the Eocene, the Green River Formation’s water chemistry purged fish and other organisms from the lake, providing room for these microbes to thrive.

    “During these times, ‘microbialites’ formed — these are rocks thought to be made by microbial processes, essentially the preserved remnants of microbial mats. The Green River Formation has a wide variety of these structures, and these features are why we went looking in these rocks, as microbialites are one life-detection target on Mars.”

    First, the researchers visually inspected the cored samples for signs of biology by identifying geological signs associated with microbialites — such as “stromatolites.”

    “These are things like finely laminated sediments, where each lamination follows the ones below, or signs of cohesive sediment, things like layers that roll over onto themselves or are at an angle steeper than what gravity would allow,” Olcott-Marshall said. “These are all thought to be signs that microbes are helping hold sediment together.”

    If visual examination pointed to the presence of biology in sections of the rock cores, the researchers looked to confirm the presence of life. They powdered those rock samples in a ball mill, and then used hot organic solvents like methanol to remove any organic carbons that might have been preserved in the rocks. That solvent was then concentrated and analyzed with gas chromatography/mass spectroscopy.

    “GC/MS allows an identification of compounds, including organic molecules, preserved in a rock,” Olcott-Marshall said. “Viking was the first time that a GC/MS was sent to Mars, and there is one up there right now on Curiosity collecting data.”

    NASA Viking 2
    NASA/Viking 2

    NASA Mars Curiosity Rover
    NASA/Mars Curiosity Rover

    Through GC/MS, the researchers determined that rock structures appearing to be biological indeed hosted living organisms millions of years ago: analysis showed the presence of lipid biomarkers.

    “A lipid biomarker is the preserved remnant of a lipid, or a fat, once synthesized by an organism,” Olcott-Marshall said. “These can be simple or very complex. Different organisms make different lipids, so identifying the biomarker can often allow a deeper understanding of the biota or the environment present when a rock was formed. These are a type of biosignature.”

    The researchers said their results could be a powerful guide for sample selection on Mars.

    “There is a GC/MS on Curiosity right now, but there are only nine sample cups dedicated for looking for biomarkers like these,” Olcott-Marshall said. “It’s crucial those nine samples are ones most likely to guarantee success. Additionally, one of the goals of the planned 2020 rover mission is to identify samples for caching for eventual return to Earth. The amount of sample that can be returned is likely very small, thus, once again, doing our best to guarantee success is very important. What this shows is that we can use visual inspection to help us screen for these samples that are likely to be successful for further biosignature analysis.”

    She said microbial and non-microbial rocks are found in similar environments, with identical preservation histories for millions of years, and many of the same chemical parameters, such as amounts of organic carbon preserved in the rocks.

    “The only difference is that one rock is shaped in a way people have associated with biology, and sure enough, those rocks are the ones that seem to preserve the biosignatures, at least in the Green River,” she said.

    See the full article here.

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    U Kansas campus

    Since its founding, the University of Kansas has embodied the aspirations and determination of the abolitionists who settled on the curve of the Kaw River in August 1854. Their first goal was to ensure that the new Kansas Territory entered the union as a free state. Another was to establish a university.

    Nearly 150 years later, KU has become a major public research and teaching institution of 28,000 students and 2,600 faculty on five campuses (Lawrence, Kansas City, Overland Park, Wichita, and Salina). Its diverse elements are united by their mission to educate leaders, build healthy communities, and make discoveries that change the world.

    A member of the prestigious Association of American Universities since 1909, KU consistently earns high rankings for its academic programs. Its faculty and students are supported and strengthened by endowment assets of more than $1.44 billion. It is committed to expanding innovative research and commercialization programs.

    KU has 13 schools, including the only schools of pharmacy and medicine in the state, and offers more than 360 degree programs. Particularly strong are special education, city management, speech-language pathology, rural medicine, clinical child psychology, nursing, occupational therapy, and social welfare. Students, split almost equally between women and men, come from all 50 states and 105 countries and are about 15 percent multicultural. The University Honors Program is nationally recognized, and KU has produced 26 Rhodes Scholars, more than all other Kansas schools combined.

  • richardmitnick 2:28 pm on September 22, 2015 Permalink | Reply
    Tags: Astrobiology, , , International Innovation, ,   

    From International Innovation- ” Life in the cosmos: Seth Shostak” 

    International Innovation


    SETI Seth Shostak
    Seth Shostak

    What is it about astronomy that captivates you?

    I find astronomy captivating, not only because it deals with huge and imposing celestial objects that have existed for billions of years, but it also answers big questions, questions that everybody, no matter where they live, might ask. Where did the Universe come from? Where is it going? What’s out there? For this reason, it’s a privilege to work in this field.

    As the only organisation addressing the full range of disciplines investigating life in the Universe, what is the Search for Extraterrestrial Intelligence (SETI) Institute’s mission?

    The Institute’s mission is to research life in the cosmos; it’s that simple. We’re not only looking for intelligent life forms – which is the purpose of the SETI experiments – we’re also looking for the existence of microbes closer to Earth, for example, on Mars or on some of the moons surrounding Saturn or Jupiter. There are more than half a dozen locations in our own solar system where life could exist, or where it could have once existed, with Mars being one of the favourites.

    Our work also involves investigating how life started on Earth, because this could give us some indication of how it might have started elsewhere, as well as finding exoplanets – planets orbiting other stars – that are possible habitats for life.

    When I joined the SETI Institute in 1991, the majority of its efforts were focused on radio SETI, which was by far its biggest project. However, today, 95 per cent of our scientists are working on what’s called astrobiology, looking for evidence of life on Mars, Jupiter, Saturn’s moons, etc. The Institute’s emphasis has greatly shifted.

    Could you share examples of R&D projects that are currently underway at the SETI Institute?

    In the astrobiology realm, there are around a dozen researchers studying the history of Mars. They are seeking to answer questions such as whatthe planet may have looked like 4 billion years ago and whether there was water on it. Today, Mars is cold and extremely dry – a terrible place for supporting life – but it wasn’t always so. The question is whether it could have supported life at one point. It’s certainly possible that we’ll find microbes there, so there is a lot of hardware roaming around the surface of Mars and orbiting the planet in an attempt to find out more about its history.

    Other researchers here are studying asteroids and meteors to find out whether they brought ingredients for life to Earth. If this is the case, it’s possible the same has happened to other planets. Similarly, a group is researching Jupiter and Saturn’s moons for water, and consequently life. We also have a team working on the New Horizons mission, which has just flown by Pluto. In fact, one of our senior research scientists, Dr Mark Showalter, found two of Pluto’s moons.

    Another important project for our astrobiologists is the search for exoplanets. We’re heavily involved with NASA’s Kepler Mission and that particular effort has found over 4,000 planets orbiting stars, some of which appear to be similar to Earth. We are also planning a large survey of dim stars, which are smaller than the Sun, because these might have habitable planets orbiting them. Finally, we’re making improvements to our equipment; for example, building new radio receivers.


    As part of a new trend in radio astronomy, the Allen Telescope Array (ATA) uses a large number of small dishes (LNSD) array to simultaneously survey numerous SETI targets. How does the ATA work and what are the key advantages of this approach?

    The ATA uses 42 relatively small antennas, which are 20 feet in diameter. This differs from past approaches in that radio telescopes built in the 1960s and 1970s used the largest possible antennas. While bigger antennas are able to receive more cosmic static and fainter signals, they are far more expensive to build. Thanks to advances in electronics, however, it’s now possible to connect a lot of small antennas together to achieve the same performance as one big antenna, only for a lot less money. Not only that, but small antennas can scan large swathes of the sky much more quickly than large antennas.

    Can you summarise the Institute’s most significant achievements to date?

    Our planetary discoveries have certainly made the headlines. For example, the planet Kepler 452b is 1,400 light-years away and orbits a star that is just like the Sun. This planet could be Earth’s cousin in that it’s a little bit bigger than Earth and its year is 385 days long rather than 365 days. Another planet, which is similar in size to Jupiter, was found by one of our astronomers around a nearby star. This planet was found using a ground-based telescope, which isn’t usually possible.

    Another significant achievement is the New Horizons mission. It took New Horizons almost ten years to arrive at Pluto, and the team working on this project didn’t know whether the spacecraft would actually make it or if there would be any data to collect at the end of its journey. It has been wonderfully successful, however, and we’ll be continuing to receive data for the next year and a half.

    In terms of the ATA, we haven’t found a signal yet, but the speed of our search is continually increasing. I have bet everyone a Starbucks coffee that we’ll find ET within 20 years. I may have to buy a lot of coffee, but there’s hope!

    What are the greatest challenges facing signal detection technology and how can the Center help to overcome these issues?

    One of the biggest challenges we face is funding because this directly affects what we can achieve and the types of equipment we can develop. The astrobiologists benefit from NASA funding but all of the Institute’s SETI experiments are privately funded. There are a number of approaches we could adopt to speed up our research; for example, the technology developed for video games uses specialised hardware that can complete computational tasks very quickly. The technical challenges associated with doing this could certainly be solved. When I bet people a cup of Starbucks coffee that we’re going to find ET, this assumes that we can develop the equipment necessary to greatly speed up our work – and this is possible if we have the funds.

    What more can be done to attract support from funding bodies and further engage the public?

    We get a lot of media attention and the public is interested in what we do. Indeed, we even have the attention of the House Committee on Science, Space & Technology in congress, where I testified about a year ago. I would say the public is aware of what we’re doing but what they don’t know is that we can’t do very much because of funding issues. Communicating that message would enable us to have a decent chance of success; if we can build the right equipment we might be able to find ET.

    Can you reveal what the future holds for the Institute?

    I’m very optimistic about the future because this really is a special time in history. We know so much more about astronomy and the planets orbiting other stars than we did when I was a kid, or even twenty-odd years ago. Now we know what’s out there, we have the ability to build equipment that could, in principle, find proof of life, whether in our solar system or somewhere else in space. This is the first time we can say this.

    I think the public recognises this at some level. Some people will have read about planets orbiting other stars or water on Mars, and it may occur to them that this could be the generation that finds extraterrestrial life. It’s rather like being alive at the end of the 15th Century when people were finally able to build wooden ships that could cross the ocean, and that rapidly changed the world as they knew it.


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  • richardmitnick 11:33 am on August 23, 2015 Permalink | Reply
    Tags: , Astrobiology, ,   

    From astrobio.net: “As Ice Age ended, greenhouse gas rise was lead factor in melting of Earth’s glaciers” 

    Astrobiology Magazine

    Astrobiology Magazine

    Aug 23, 2015
    No Writer Credit

    Improved dating methods reveal that the rise in carbon dioxide levels was the primary cause of the simultaneous melting of glaciers around the globe during the last Ice Age. The new finding has implications for rising levels of man-made greenhouse gases and retreating glaciers today. Courtesy: NSF

    A fresh look at some old rocks has solved a crucial mystery of the last Ice Age, yielding an important new finding that connects to the global retreat of glaciers caused by climate change today, according to a new study by a team of climate scientists.

    For decades, researchers examining the glacial meltdown that ended 11,000 years ago took into account a number of contributing factors, particularly regional influences such as solar radiation, ice sheets and ocean currents.

    But a reexamination of more than 1,000 previously studied glacial boulders has produced a more accurate timetable for the pre-historic meltdown and pinpoints the rise in carbon dioxide – then naturally occurring – as the primary driving factor in the simultaneous global retreat of glaciers at the close of the last Ice Age, the researchers report in the journal Nature Communications.

    “Glaciers are very sensitive to temperature. When you get the world’s glaciers retreating all at the same time, you need a broad, global reason for why the world’s thermostat is going up,” said Boston College Assistant Professor of Earth and Environmental Sciences Jeremy Shakun. “The only factor that explains glaciers melting all around the world in unison during the end of the Ice Age is the rise in greenhouse gases.”

    The researchers found that regional factors caused differences in the precise timing and pace of glacier retreat from one place to another, but carbon dioxide was the major driver of the overall global meltdown, said Shakun, a co-author of the report “Regional and global forcing of glacier retreat during the last deglaciation.”

    “This is a lot like today,” said Shakun. “In any given decade you can always find some areas where glaciers are holding steady or even advancing, but the big picture across the world and over the long run is clear – carbon dioxide is making the ice melt.”

    While 11,000 years ago may seem far too distant for a point of comparison, it was only a moment ago in geological time. The team’s findings fix even greater certainty on scientific conclusions that the dramatic increase in manmade greenhouse gases will eradicate many of the world’s glaciers by the end of this century.

    “This has relevance to today since we’ve already raised CO2 by more than it increased at the end of the Ice Age, and we’re on track to go up much higher this century — which adds credence to the view that most of the world’s glaciers will be largely gone within the next few centuries, with negative consequences such as rising sea level and depleted water resources,” said Shakun.

    The team reexamined samples taken from boulders that were left by the retreating glaciers, said Shakun, who was joined in the research by experts from Oregon State University, University of Wisconsin-Madison, Purdue University and the National Center for Atmospheric Research in Boulder, Colo.

    Each boulder has been exposed to cosmic radiation since the glaciers melted, an exposure that produces the isotope Beryllium-10 in the boulder. Measuring the levels of the isotope in boulder samples allows scientists to determine when glaciers melted and first uncovered the boulders.

    Scientists have been using this process called surface exposure dating for more than two decades to determine when glaciers retreated, Shakun said. His team examined samples collected by multiple research teams over the years and applied an improved methodology that increased the accuracy of the boulder ages.

    The team then compared their new exposure ages to the timing of the rise of carbon dioxide concentration in the atmosphere, a development recorded in air bubbles taken from ice cores. Combined with computer models, the analysis eliminated regional factors as the primary explanations for glacial melting across the globe at the end of the Ice Age. The single leading global factor that did explain the global retreat of glaciers was rising carbon dioxide levels in the air.

    “Our study really removes any doubt as to the leading cause of the decline of the glaciers by 11,000 years ago – it was the rising levels of carbon dioxide in the Earth’s atmosphere,” said Shakun.

    Carbon dioxide levels rose from approximately 180 parts per million to 280 parts per million at the end of the last Ice Age, which spanned nearly 7,000 years. Following more than a century of industrialization, carbon dioxide levels have now risen to approximately 400 parts per million.

    “This tells us we are orchestrating something akin to the end of an Ice Age, but much faster. As the amount of carbon dioxide continues to increase, glaciers around the world will retreat,” said Shakun.

    See the full article here.

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  • richardmitnick 11:22 am on August 9, 2015 Permalink | Reply
    Tags: Astrobiology, , , E.T.,   

    From Daily Galaxy: “New Advances in the Search for Extraterrestrial Life –‘Will It Be Inconceivable to Us?'” 

    Daily Galaxy
    The Daily Galaxy

    August 09, 2015
    No Writer Credit

    No image credit

    A thin layer near the surface of Earth is teeming with life of huge diversity: from micro-organisms to plants and animals, and even intelligent species. Up to now, this forms the only known sample of life in the Universe. We now readily accept that the laws and concepts of physics and chemistry apply throughout the cosmos. Is there a general biology as well: is there life beyond Earth?
    With the Sun just about half-way through its life-time, humankind as we know it is likely to constitute a rather short transient episode, and advanced extra-terrestrial life might be inconceivable to us in its complexity, just as human life is to amoebae.

    Pinpoints of light in the night sky have probably always made humankind speculate about the existence of other worlds, but the presence of planets orbiting stars other than the Sun has become a proven reality only within the last 15 years. While the vast majority of the more than 450 [number is far larger] extra-solar planets that are known to date are gas giants like Jupiter and Saturn, some spectacular discoveries of about 20 planets of less than 10 Earth masses have already indicated that rocky planets with conditions suitable to harbour life are probably rather common.

    One of the big unknowns is how likely it is for life to emerge once all conditions are right. There is no lack of its building blocks; the number of molecules fundamental to Earth’s biochemistry that have already been found in the interstellar medium, planetary atmospheres and on the surfaces of comets, asteroids, meteorites and interplanetary dust particles is surprisingly large. Giant “factories”, where complex molecules are being synthesised, appear to make carbonaceous compounds ubiquitous in the Universe.

    If the genesis of life arises from chemistry with a high probability, one might speculate whether this process occurred more than once on Earth itself, leading to the existence of a terrestrial “shadow biosphere” with a distinct Tree of Life. Moreover, there are several other promising targets within the Solar System, namely Mars, Europa, Enceladus, and, for biochemistry based on a liquid other than water, Titan. Evidence for life is not easy to gather; any chemical footprint needs to be unambiguously characteristic, and to exclude an abiogenic origin. The most powerful probe would result from returning a sample to a laboratory on Earth.

    The year 2010 marks the 50th anniversary of the first search for radio signals originating from other civilizations and up to now all “Search for Extra-Terrestrial Intelligence” (SETI) experiments have provided a negative result.

    Allen Telescope Array
    SETI Institut’s Allen Telescope Array

    SETI@home screensaver
    SETI@home massive personal computer project

    However these have probed only up to about 200 light-years distant, whereas the center of the Milky Way is 25,000 light-years away from us. And, even if there is no other intelligent life in the Milky Way, it could still be hosted in another of the remaining hundreds of billions of other galaxies.

    Advanced efforts are now on the drawing board or already underway for the further exploration of the Solar System and the detection of biomarkers in the atmospheres of extra-solar planets, while searches for signals of extra-terrestrial intelligence are entering a new era with the deployment of the next generation of radio telescopes.

    With the detection of extra-terrestrial life being technically feasible, one needs to address whether perceived societal benefits create an imperative to search for it, or whether such an endeavour may rather turn out to be a threat to our own existence.

    Evolutionary convergence, as seen in the biological history on Earth, suggests that the limited number of solutions to sensory and social organizational problems will make alien civilizations at a comparable stage of evolution not look too different from our own. As historical examples indicate, meeting a civilization similar to ours might actually turn into a disaster.

    Rather than aliens invading Earth, realistically expected detection scenarios will involve microbial organisms and/or extra-terrestrial life at a safe distance that prevents physical contact. As far as exploring other lifeforms is concerned, any applied strategy must exclude biological contamination – not only to protect ourselves, but also to support cosmic biodiversity. No legally enforceable procedures are in place yet, and a broad dialogue on the development of a societal agenda on extra-terrestrial life is required.

    The search for life elsewhere is nothing but a search for ourselves, where we came from, why we are here, and where we will be going. It encompasses many, if not all, of the fundamental questions in biology, physics, and chemistry, but also in philosophy, psychology, religion and the way in which humans interact with their environment and each other. The question of whether we are alone in the Universe still remains unanswered, with no scientific evidence yet supporting one possible outcome or the other. If, however, extra-terrestrial life does exist, an emerging new age of exploration may well allow living generations to witness its detection.

    See the full article here.

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  • richardmitnick 10:59 am on August 6, 2015 Permalink | Reply
    Tags: Astrobiology, ,   

    From NASA Astrobiology: “Researchers Use ‘Seafloor Gardens’ to Switch on Light Bulb” 



    NASA Astrobiology Institute

    Aug. 5, 2015
    Whitney Clavin 818-354-4673
    Jet Propulsion Laboratory, Pasadena, Calif.

    This photo simulation shows a laboratory-created “chemical garden,” which is a chimney-like structure found at bubbling vents on the seafloor. Some researchers think life on Earth might have got its start at structures like these billions of years ago, partly due to their ability to transfer electrical currents — an essential trait of life as we know it. The battery-like property of these chemical gardens was demonstrated by linking several together in series to light an LED (light-emitting diode) bulb. In this photo simulation, the bulb is not really attached to the chimney.
    The chimney membranes are made of iron sulfides and iron hydroxides, geologic materials that conduct electrons. Image credit: NASA/JPL-Caltech

    One of the key necessities for life on our planet is electricity. That’s not to say that life requires a plug and socket, but everything from shrubs to ants to people harnesses energy via the transfer of electrons — the basis of electricity. Some experts think that the very first cell-like organisms on Earth channeled electricity from the seafloor using bubbling, chimney-shaped structures, also known as chemical gardens.

    In a new study, researchers report growing their own tiny chimneys in a laboratory and using them to power a light bulb. The findings demonstrate that the underwater structures may have indeed given an electrical boost to Earth’s very first life forms.

    A laboratory-created “chemical garden” made of a combination of black iron sulfide and orange iron hydroxide/oxide is shown in this photo. Chemical gardens are a nickname for chimney-like structures that form at bubbling vents on the seafloor. Some researchers think that life may have originated at structures like these billions of years ago.

    “These chimneys can act like electrical wires on the seafloor,” said Laurie Barge of NASA’s Jet Propulsion Laboratory, Pasadena, California, lead author of a new paper on the findings in the journal Angewandte Chemie International Edition. “We’re harnessing energy as the first life on Earth might have.”

    This image from the floor of the Atlantic Ocean shows a collection of limestone towers known as the “Lost City.” Alkaline hydrothermal vents of this type are suggested to be the birthplace of the first living organisms on the ancient Earth.
    Credits: D. Kelley and M. Elend/University of Washington

    The findings are helping researchers put together the story of life on Earth, starting with the first chapter of its origins. How life first took root on our nascent planet is a topic riddled with many unanswered chemistry questions. One leading theory for the origins of life, called the alkaline vent hypothesis, is based on the idea that life sprang up underwater with the help of warm, alkaline (as opposed to acidic) chimneys.

    Chimneys naturally form on the seafloor at hydrothermal vents. They range in size from inches to tens of feet (centimeters to tens of meters), and they are made of different types of minerals with, typically, a porous structure. On early Earth, these chimneys could have established electrical and proton gradients across the thin mineral membranes that separate their compartments. Such gradients emulate critical life processes that generate energy and organic compounds.

    “Life doesn’t want to get electrocuted, but needs just the right amount of electricity,” said Michael Russell of JPL, a co-author of the study. “This new experiment confirms what that amount of electricity is — just under a volt.” Russell first proposed the alkaline vent hypothesis in 1989, and even predicted the existence of alkaline vent chimneys more than a decade before they were actually discovered in the Atlantic Ocean and dubbed “The Lost City.”

    Previously, researchers at the University of Tokyo and the Japan Agency for Marine-Earth Science and Technology recorded electricity in “black smoker” vent chimneys in the Okinawa Trough in Japan. Black smokers are acidic — and hotter and harsher — than alkaline vents.

    The new study demonstrates that laboratory chimneys similar to alkaline vents on early Earth had enough electricity to do something useful — in this case power an LED (light-emitting diode) light bulb. The researchers connected four of the chemical gardens, submerged in iron-containing fluids, to turn on one light bulb. The process took months of patient laboratory work by Barge and Russell’s team, with the help of an undergraduate student intern at JPL, Yeghegis “Lily” Abedian.

    “I remember when Lily told me the light bulb had turned on. It was shocking,” said Barge (while admitting she likes a good pun).

    The scientists hope to do the experiment again using different materials for their laboratory chimneys. In the current study, they made chimneys of iron sulfide and iron hydroxide, geological materials that can conduct electrons. Future experiments can assess the electrical potential of additional materials thought to have been present in Earth’s early oceans and hydrothermal vents, such as molybdenum, nickel, hydrogen and carbon dioxide.

    “With the right recipe, maybe one chimney alone will be able to light the LED – or instead, we could use that electrochemical energy to power other reactions,” said Barge. “We can also start simulating higher temperature and pressures that occur at hydrothermal vents.”

    Materials or other energy sources thought to have been involved in the possible development of life on other planets and moons can be tested too, such as those on early Mars, or icy worlds like Jupiter’s moon Europa.

    The electrical needs of life’s first organisms are only one of many puzzles. Other researchers are trying to figure out how organic materials, such as DNA, might have assembled from scratch. The ultimate goal is to fit all the pieces together into one amazing story of life’s origins.

    The JPL research team is part of the Icy Worlds team of the NASA Astrobiology Institute, based at NASA’s Ames Research Center in Moffett Field, California. The Icy Worlds team is led by Isik Kanik of JPL.

    JPL is managed by the California Institute of Technology in Pasadena for NASA.

    For more information about the NASA Astrobiology Institute, visit:


    See the full article here.

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    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 2:08 pm on July 29, 2015 Permalink | Reply
    Tags: , Astrobiology, ,   

    From astrobio.net: “‘Carbon sink’ detected underneath world’s deserts” 

    Astrobiology Magazine

    Astrobiology Magazine

    Jul 29, 2015
    No Writer Credit

    Scientists followed the journey of water through the Tarim Basin from the rivers at the edge of the valley to the desert aquifers under the basin. They found that as water moved through irrigated fields, the water gathered dissolved carbon and moved it deep underground. Credit: Yan Li

    The world’s deserts may be storing some of the climate-changing carbon dioxide emitted by human activities, a new study suggests. Massive aquifers underneath deserts could hold more carbon than all the plants on land, according to the new research.

    Humans add carbon dioxide to the atmosphere through fossil fuel combustion and deforestation. About 40 percent of this carbon stays in the atmosphere and roughly 30 percent enters the ocean, according to the University Corporation for Atmospheric Research. Scientists thought the remaining carbon was taken up by plants on land, but measurements show plants don’t absorb all of the leftover carbon. Scientists have been searching for a place on land where the additional carbon is being stored—the so-called “missing carbon sink.”

    The new study suggests some of this carbon may be disappearing underneath the world’s deserts – a process exacerbated by irrigation. Scientists examining the flow of water through a Chinese desert found that carbon from the atmosphere is being absorbed by crops, released into the soil and transported underground in groundwater—a process that picked up when farming entered the region 2,000 years ago.

    Underground aquifers store the dissolved carbon deep below the desert where it can’t escape back to the atmosphere, according to the new study.

    The new study estimates that because of agriculture roughly 14 times more carbon than previously thought could be entering these underground desert aquifers every year. These underground pools that taken together cover an area the size of North America may account for at least a portion of the “missing carbon sink” for which scientists have been searching.

    “The carbon is stored in these geological structures covered by thick layers of sand, and it may never return to the atmosphere,” said Yan Li, a desert biogeochemist with the Chinese Academy of Sciences in Urumqi, Xinjiang, and lead author of the study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union. “It is basically a one-way trip.”

    Knowing the locations of carbon sinks could improve models used to predict future climate change and enhance calculations of the Earth’s carbon budget, or the amount of fossil fuels humans can burn without causing major changes in the Earth’s temperature, according to the study’s authors.

    Although there are most likely many missing carbon sinks around the world, desert aquifers could be important ones, said Michael Allen, a soil ecologist from the Center for Conservation Biology at the University of California-Riverside who was not an author on the new study.

    If farmers and water managers understand the role heavily-irrigated inland deserts play in storing the world’s carbon, they may be able to alter how much carbon enters these underground reserves, he said.

    “This means [managers] can take practical steps that could play a role in addressing carbon budgets,” said Allen.

    Researchers gathered groundwater flowing under the desert sands. The amount of carbon carried by this underground flow increased quickly when the Silk Road, which opened the region to farming, began 2,000 years ago. Credit: Yan Li

    Examining desert water

    To find out where deserts tucked away the extra carbon, Li and his colleagues analyzed water samples from the Tarim Basin, a Venezuela-sized valley in China’s Xinjiang region. Water draining from rivers in the surrounding mountains support farms that edge the desert in the center of the basin.

    The researchers measured the amount of carbon in each water sample and calculated the age of the carbon to figure out how long the water had been in the ground.

    The study shows the amount of carbon dioxide dissolved in the water doubles as it filters through irrigated fields. The scientists suggest carbon dioxide in the air is taken up by the desert crops. Some of this carbon is released into the soil through the plant’s roots. At the same time, microbes also add carbon dioxide to the soil when they break down sugars in the dirt. In a dry desert, this gas would work its way out of the soil into the air. But on arid farms, the carbon dioxide emitted by the roots and microbes is picked up by irrigation water, according to the new study.

    In these dry regions, where water is scarce, farmers over-irrigate their land to protect their crops from salts that are left behind when water used for farming evaporates. Over-irrigating washes these salts, along with carbon dioxide that is dissolved in the water, deeper into the earth, according to the new study.

    Although this process of carbon burial occurs naturally, the scientists estimate that the amount of carbon disappearing under the Tarim Desert each year is almost 12 times higher because of agriculture. They found that the amount of carbon entering the desert aquifer in the Tarim Desert jumped around the time the Silk Road, which opened the region to farming, begin to flourish.

    After the carbon-rich water flows down into the aquifer near the farms and rivers, it moves sideways toward the middle of the desert, a process that takes roughly 10,000 years.

    Any carbon dissolved in the water stays underground as it makes its way through the aquifer to the center of the desert, where it remains for thousands of years, according to the new study.

    Estimating carbon storage

    Based on the various rates that carbon entered the desert throughout history, the study’s authors estimate 20 billion metric tons (22 billion U.S. tons) of carbon is stored underneath the Tarim Basin desert, dissolved in an aquifer that contains roughly 10 times the amount of water held in the North American Great Lakes.

    The study’s authors approximate the world’s desert aquifers contain roughly 1 trillion metric tons (1 trillion U.S. tons) of carbon—about a quarter more than the amount stored in living plants on land.

    Li said more information about water movement patterns and carbon measurements from other desert basins are needed to improve the estimate of carbon stored underneath deserts around the globe.

    Allen said the new study is “an early foray” into this research area. “It is as much a call for further research as a definitive final answer,” he said.

    See the full article here.

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  • richardmitnick 7:32 pm on April 9, 2015 Permalink | Reply
    Tags: Astrobiology, , ,   

    From astrobio.net: “Can we find an ancient Earth-like planet with a dying biosphere?” 

    Astrobiology Magazine

    Astrobiology Magazine

    Apr 9, 2015
    Amanda Doyle

    The life cycle of a solar-like star shows how our Sun will expand into a red giant. Credit: ESO/M. Kornmesser

    Our Sun will evolve into a red giant star billions of years from now. The increased heat from the expanding Sun will scorch the Earth with dire effects to life. Climate models can be used to predict how this will happen, but, of course, this cannot be tested out on Earth.

    Jack O’Malley-James of the Institute for Pale Blue Dots at Cornell University, along with colleagues, have been calculating the chances of discovering an old-Earth analog approaching the end of its habitable lifetime. This follows his work on Swansong Biospheres in which the potential bio-signatures of a dying world were assessed. The new paper, In Search of Future Earths: Assessing the possibility of finding Earth analogues in the later stages of their habitable lifetimes, has been accepted for publication in the journal Astrobiology and is available in preprint.

    The far future Earth

    Searches are already in place to find Earth’s twin, a planet with a similar mass and radius as the Earth and orbiting at the same distance as the Earth does from the Sun. However, finding an equivalent of Earth’s much older cousin involves a different set of criteria.

    The “habitable zone” is defined as the region where liquid water can exist on the surface of a planet. Habitable zones move outwards as a star ages, so a planet that was in the zone when the star was younger may not necessarily remain there. An old Earth analogue is one that has been in the star’s habitable zone for the entire main sequence lifetime of the star, known as the continuously habitable zone. As the purpose is to study planets in the final stages of habitability, a far future Earth would also have to be approaching the inner edge of the habitable zone.

    The habitable zone (in blue) extends to greater distances for stars hotter than the Sun. Similarly, the habitable zone will move outwards as our Sun becomes a red giant. The continuously habitable zone is a smaller region where a planet can remain habitable throughout the main sequence lifetime of the star. Credit: Wikimedia

    As up to one-third of main sequence solar-like stars are thought to be in the later stages of their evolution, it is feasible that old Earth analogues could be detected. If any of these planets exist in the solar neighborhood, then they would be excellent candidates for future space telescopes with the capability to characterize a planet’s atmosphere from its spectrum.

    Searching nearby

    There are six solar-like stars within 10 parsecs of the Sun that are old enough to harbor an old Earth analogue.

    A parsec is the distance from the Sun to an astronomical object that has a parallax angle of one arcsecond (the diagram is not to scale).

    A parsec is the equivalent of 3.26 light years. O’Malley-James calculated the location of the habitable zone for each star over its entire lifetime. He then placed hypothetical planets in each system at a distance where the planet could remain habitable for billions of years. The temperature changes on the planet over the main sequence lifetime of the star can be modeled by comparing the predicted incoming and outgoing radiation.

    The paper concludes that if Earth-like planets existed around these stars, then the one around 61 Vir would be at the right stage of its lifetime to be considered a far future Earth. Such a planet might be home to a declining microbial population, assuming that life evolved there in a similar manner to the Earth. This hypothetical planet would be akin to the stage in future Earth’s lifetime when the temperature has risen too high for complex life to survive, and microbes are the last lifeforms to cling to existence. Other stars could host planets similar to future Earth where only extremophile microbial life remains in a few select niches, however these biosignatures would be much more difficult to detect than the declining microbial biosphere.

    A Galaxy Teeming with Earth-like Planets?

    If an Earth-like planet existed around 61 Vir, it would provide a good opportunity to study the far future Earth. But what are the actual chances of such planets existing?

    O’Malley-James used previous studies by other scientists in order to find out. One study, based on the number of planets found by NASA’s Kepler mission, predicts that 8.6 percent of solar-like stars could harbor an Earth-like planet orbiting in the habitable zone.

    NASA Kepler Telescope

    A solar-like star is one that is of a similar temperature and mass as our own Star. There are 276 stars like our Sun within 100 parsecs, around half of which are older than six billion years. This means that there should be 11 potential targets.

    61 Vir as seen with a 12.5″ telescope with a field of view of 45.1 arc minutes. Credit: Kevin Heider

    However, another study showed that terrestrial planets are more likely to form less than one astronomical unit (AU), the distance between the Sun and the Earth) from the star. From the six example stars that O’Malley-James studied, the continuously habitable zone is located slightly further from the star than this. Combining these results indicates that there would actually only be one potential old-Earth analogue within the solar neighborhood.

    “It turned out that these planets are probably not that common at all, so in reality any habitable planets in the 61 Vir system will probably not resemble an older version of Earth,” said O’Malley-James. “This study highlights that finding replicas of our own world, in terms of the diversity and complexity of life, is going to be a much harder task than simply finding life.”

    Yet while there may only be one potential old-Earth analogue close enough to be studied in detail, there could still be thousands more in the distant reaches of our Galaxy.

    See the full article here.

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  • richardmitnick 2:46 pm on March 7, 2015 Permalink | Reply
    Tags: , Astrobiology, ,   

    From astrobio.net: “NASA Ames Reproduces the Building Blocks of Life in Laboratory” 

    Astrobiology Magazine

    Astrobiology Magazine

    Mar 7, 2015
    No Writer Credit

    Left to right: Ames scientists Michel Nuevo, Christopher Materese and Scott Sandford reproduce uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory. Image Credit: NASA/ Dominic Hart

    NASA scientists studying the origin of life have reproduced uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory. They discovered that an ice sample containing pyrimidine exposed to ultraviolet radiation under space-like conditions produces these essential ingredients of life.

    Pyrimidine is a ring-shaped molecule made up of carbon and nitrogen and is the central structure for uracil, cytosine, and thymine, which are all three part of a genetic code found in ribonucleic (RNA) and deoxyribonucleic acids (DNA). RNA and DNA are central to protein synthesis, but also have many other roles.

    “We have demonstrated for the first time that we can make uracil, cytosine, and thymine, all three components of RNA and DNA, non-biologically in a laboratory under conditions found in space,” said Michel Nuevo, research scientist at NASA’s Ames Research Center, Moffett Field, California. “We are showing that these laboratory processes, which simulate conditions in outer space, can make several fundamental building blocks used by living organisms on Earth.”

    An ice sample is deposited on a cold (approximately –440 degrees Fahrenheit) substrate in a chamber, where it is irradiated with high-energy ultraviolet (UV) photons from a hydrogen lamp. The bombarding photons break chemical bonds in the ices and break down the ice’s molecules into fragments that then recombine to form new compounds, such as uracil, cytosine, and thymine.

    Pyrimidine is a ring-shaped molecule made up of carbon and nitrogen and is the central structure for uracil, cytosine, and thymine, which are found in RNA and DNA. Image Credit: NASA

    NASA Ames scientists have been simulating the environments found in interstellar space and the outer Solar System for years. During this time, they have studied a class of carbon-rich compounds, called polycyclic aromatic hydrocarbons (PAHs), that have been identified in meteorites, and which are the most common carbon-rich compound observed in the universe. PAHs typically are structures based on several six-carbon rings that resemble fused hexagons, or a piece of chicken wire.

    The molecule pyrimidine is found in meteorites, although scientists still do not know its origin. It may be similar to the carbon-rich PAHs, in that it may be produced in the final outbursts of dying, giant red stars, or formed in dense clouds of interstellar gas and dust.

    “Molecules like pyrimidine have nitrogen atoms in their ring structures, which makes them somewhat wimpy. As a less stable molecule, it is more susceptible to destruction by radiation, compared to its counterparts that don’t have nitrogen,” said Scott Sandford, a space science researcher at Ames. “We wanted to test whether pyrimidine can survive in space, and whether it can undergo reactions that turn it into more complicated organic species, such as the nucleobases uracil, cytosine, and thymine.”

    The ring-shaped molecule pyrimidine is found in cytosine and thymine. Image Credit: NASA

    In theory, the researchers thought that if molecules of pyrimidine could survive long enough to migrate into interstellar dust clouds, they might be able to shield themselves from destructive radiation. Once in the clouds, most molecules freeze onto dust grains (much like moisture in your breath condenses on a cold window during winter).

    These clouds are dense enough to screen out much of the surrounding outside radiation of space, thereby providing some protection to the molecules inside the clouds.

    Scientists tested their hypotheses in the Ames Astrochemistry Laboratory. During their experiment, they exposed the ice sample containing pyrimidine to ultraviolet radiation under space-like conditions, including a very high vacuum, extremely low temperatures (approximately –440 degrees Fahrenheit), and harsh radiation.

    They found that when pyrimidine is frozen in ice mostly consisting of water, but also ammonia, methanol, or methane, it is much less vulnerable to destruction by radiation than it would be if it were in the gas phase in open space. Instead of being destroyed, many of the molecules took on new forms, such as the RNA/DNA components uracil, cytosine, and thymine, which are found in the genetic make-up of all living organisms on Earth.

    “We are trying to address the mechanisms in space that are forming these molecules. Considering what we produced in the laboratory, the chemistry of ice exposed to ultraviolet radiation may be an important linking step between what goes on in space and what fell to Earth early in its development,” said Christopher Materese, another researcher at NASA Ames who has been working on these experiments.

    An ice sample is held at approximately -440 degrees Fahrenheit in a vacuum chamber, where it is irradiated with high energy UV photons from a hydrogen lamp. The bombarding photons break chemical bonds in the ice samples and result in the formation of new compounds, such as uracil. Image Credit: NASA/Dominic Hart

    “Nobody really understands how life got started on Earth. Our experiments suggest that once the Earth formed, many of the building blocks of life were likely present from the beginning. Since we are simulating universal astrophysical conditions, the same is likely wherever planets are formed,” says Sandford.

    Additional team members who helped perform some of the research are Jason Dworkin, Jamie Elsila, and Stefanie Milam, three NASA scientists at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    The research was funded by the NASA Astrobiology Institute (NAI) and the NASA Origins of Solar Systems Program. The NAI is a virtual, distributed organization of competitively-selected teams that integrates and funds astrobiology research and training programs in concert with the national and international science communities.

    See the full article here.

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  • richardmitnick 7:03 pm on February 9, 2015 Permalink | Reply
    Tags: Astrobiology, , ,   

    From astrobio: “Planets Orbiting Red Dwarfs May Stay Wet Enough for Life” 

    Astrobiology Magazine

    Astrobiology Magazine

    Feb 9, 2015
    Charles Q. Choi

    Oceans currents would transport heat to the dark side of tidally-locked exoplanets. Image Credit: Lynette Cook

    Small, cold stars known as red dwarfs are the most common type of star in the Universe, and the sheer number of planets that may exist around them potentially make them valuable places to hunt for signs of extraterrestrial life.

    However, previous research into planets around red dwarfs suggested that while they may be warm enough to host life, they might also completely dry out, with any water they possess locked away permanently as ice. New research published on the topic finds that these planets may stay wet enough for life after all. The scientists detailed their findings online on November 12 in The Astrophysical Journal Letters.

    Red dwarfs, also known as M stars, are roughly one-fifth as massive as the Sun and up to 50 times fainter. These stars comprise up to 70 percent of the stars in the cosmos, and NASA’s Kepler space observatory has discovered that at least half of these stars host rocky planets that are one-half to four times the mass of Earth.

    NASA Kepler Telescope

    Red dwarf planets are potentially key places to search for life as we know it, not just because there are so many of them, but also because of their incredible longevity. Unlike our Sun, which will die in a few billion years, red dwarfs will take trillions of years to burn through their fuel, significantly longer than the age of the Universe, which is less than 14 billion years old. This longevity potentially gives red dwarfs a great deal more time for life to evolve around them.

    Research into whether a distant world might host life as we know it usually focuses on whether or not it has liquid water, since there is life virtually everywhere there is liquid water on Earth, even miles underground. Scientists typically concentrate on habitable zones, the area around a star where it is neither too hot for all its surface water to boil away, nor too cold enough for all its surface water to freeze.

    Recent findings suggest that planets in the habitable zones of red dwarf stars could accumulate significant amounts of water. In fact, each planet could possess about 25 times more water than Earth.

    The habitable zones of red dwarfs are close to these stars because of how dim they are, often closer than the distance Mercury orbits the Sun. This closeness makes them appealing to astrobiologists, since planets near their stars cross in front of them more often, making them easier to detect than planets that orbit farther away.

    However, when a planet orbits very near a star, the star’s gravitational pull can force the world to become “tidally locked” to it. When a planet is tidally locked to its star, it will always show the same side to its star, just as the Moon always shows the same side to Earth. This causes the planet to have one permanent day side and one permanent night side.


    The extremes of heat and cold that tidally locked planets experience could make them profoundly different from Earth. For example, prior research speculated the dark sides of tidally locked planets would become so cold that any water there would freeze. Sunlight would make water on the sunlit side evaporate, and this water vapor could get carried by air currents to the night sides, eventually leading to sheets of ice miles thick on the night sides and removing all water from the sunlit sides. Life as we know it probably could not develop on the day sides of such planets. Although they would have sunlight for photosynthesis, they would have no water to serve as the primordial soup for life to swim in.

    To see how habitable tidally-locked planets really are, scientists devised a 3D global climate model of planets that simulated interactions between the atmosphere, ocean, sea ice, and land, as well as a 3-D model of ice sheets large enough to cover entire continents. They also simulated a red dwarf with a temperature of about 5,660 degrees Fahrenheit (3,125 degrees Celsius), and investigated whether all the water on these planets would indeed get trapped on their night sides.

    “I’ve been interested in trying to make calculations relevant for M-star planet habitability since being convinced by astronomers that these types of planets will likely be closest (in proximity) to Earth,” said study co-author Dorian Abbot, a geoscientist at the University of Chicago.

    For instance, the nearest known star to the Sun, Proxima Centauri, is a red dwarf, and it remains uncertain whether or not it has a planet. The possibility that red dwarf planets might be relatively near to Earth “means that anything geoscientists can tell astronomers about habitability of these planets will be essential for planning future missions.”

    The researchers simulated planets of Earth’s size and gravity that experienced between 63 percent and 77 percent as much sunlight as Earth. They also modeled a super-Earth planet 50 percent wider than Earth with 38 percent stronger gravity, because astronomers have discovered super-Earth worlds around red dwarfs. For instance, Gliese 667Cb, a super-Earth at least 4.5 times the mass of Earth, orbits Gliese 667C, a red dwarf about 22 light years from Earth. They set this super-Earth on an orbit where it received about two-thirds as much as sunlight as Earth.

    The researchers modeled three different arrangements of continents for all these planets. One was a water world with no continents and global oceans of varying depths. Another involved a supercontinent covering the night side and an ocean covering the day side. The last mimicked Earth’s configuration of continents. The planets also had atmospheres similar to Earth’s, but the researchers also tested lower levels of the greenhouse gas, carbon dioxide, which traps heat and helps keep planets warm.

    When it came to super-Earths covered entirely in water, and super-Earths with continental arrangements like Earth’s, the researchers found it was unlikely that all their water would get trapped on their night sides.

    “This is because surface winds transport sea ice to the day side where it is melted easily,” said lead study author Jun Yang at the University of Chicago.

    Moreover, ocean currents transport heat from the day side to the night side on these planets.

    “Ocean heat transport strongly influences the climate and sea ice thickness on our Earth,” Yang said. “We found this may also work on exoplanets.”

    If a super-Earth has very large continents covering most of its night side, the scientists discovered ice sheets of at least 3,300 feet (1,000 meters) thick could grow on its night side. However, the day sides of these super-Earths would dry out completely only if they received less geothermal heat from volcanic activity than Earth, and had 10 percent of the amount of water on Earth’s surface or less. Similar results were seen with Earth-sized planets.

    “The important implication is that it may be easier than previously thought to keep liquid water on the dayside of a tidally locked planet, where photosynthesis is possible,” Abbot said. “There are many issues that will affect the habitability of M-star planets, but our results suggest at least that water-trapping on the night side will only be a problem for relatively dry planets with large continents on their nightside and relatively low geothermal heat flux.”

    Based on present and near-future technology, Yang said it would be very difficult for astronomers to gauge how thick the sea ice or the ice sheets are on the night sides of red dwarf planets and test whether their models are correct. Still, using current and upcoming technology “it may be possible to know whether the day sides are dry or not,” Yang said.

    See the full article here.

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