Tagged: Astrobiology Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 12:41 pm on September 26, 2021 Permalink | Reply
    Tags: "How to Search for Life as We Don't Know It", , Astrobiology, , ,   

    From Scientific American (US) : “How to Search for Life as We Don’t Know It” 

    From Scientific American (US)

    September 26, 2021
    Avi Loeb

    Much of astrobiology is focused on looking for organisms with chemistry similar to ours—but there could well be other kinds.

    1
    Credit: Getty Images.

    In my freshman seminar at Harvard last semester, I mentioned that the nearest star to the sun, Proxima Centauri, emits mostly infrared radiation and has a planet, Proxima b, in the habitable zone around it.

    As a challenge to the students, I asked: “Suppose there are creatures crawling on the surface of Proxima b? What would their infrared-sensitive eyes look like?” The brightest student in class responded within seconds with an image of the mantis shrimp, which possesses infrared vision. The shrimp’s eyes look like two ping-pong balls connected with cords to its head. “It looks like an alien,” she whispered.

    When trying to imagine something we’ve never seen, we often default to something we have seen. For that reason, in our search for extraterrestrial life we are usually looking for life as we know it. But is there a path for expanding our imagination to life as we don’t know it?

    In physics, an analogous path was already established a century ago and turned out to be successful in many contexts. It involves conducting laboratory experiments that reveal the underlying laws of physics, which in turn apply to the entire universe. For example, around the same time when the neutron was discovered in the laboratory of James Chadwick in 1932, Lev Landau suggested that there might be stars made of neutrons. Astronomers realized subsequently that there are, in fact, some 100 million neutron stars in our Milky Way galaxy alone—and a billion times more in the observable universe. Recently, the LIGO experiment detected gravitational-wave signals from collisions between neutron stars at cosmological distances. It is now thought that such collisions produce the precious gold that is forged into wedding bands. The moral of this story is that physicists were able to imagine something new in the universe at large and search for it in the sky by following insights gained from laboratory experiments on Earth.

    The search for extraterrestrial life can follow a similar approach. By creating synthetic life in various ways from a soup of chemicals in the lab, we might be able to imagine new environments where life might occur differently than on Earth. The situation is similar to composing a recipe book with prescriptions for baking different types of cakes. In order to write a rich recipe book, we need to experiment with many types of chemicals. And also, as I noted in a paper with Manasvi Lingam, this experimentation may use fluids other than water, which is considered essential for life as we know it.

    One of my Harvard colleagues, the Nobel laureate Jack Szostak, is getting close to creating synthetic life in his laboratory. Any success with a single recipe may suggest variations that would produce a diversity of outcomes, to be assembled into our recipe book for synthetic life. By identifying suitable environmental conditions from our laboratory experiments, we can later search for real systems where they are realized in the sky, just as in the case of neutron stars.

    In following this approach, we should be as careful as we are in tapping nuclear energy. Creating artificial variants of life in our laboratories brings the risk of causing an environmental disaster, as imagined in the story of Frankenstein. Such experimentation must be performed in isolated environments so that mishaps with life as we don’t know it will not endanger the life we know.

    Although the surfaces of planets and asteroids can be explored remotely for biological signatures, extraterrestrial life might be most abundant under the surface. Habitable conditions could exist in the oceans that lie under thick icy surfaces, not only within moons like Saturn’s Enceladus or Jupiter’s Europa, but also inside free-floating objects in interstellar space. In other research with Lingam, we showed that the number of life-bearing objects could exceed the number of rocky planets in the habitable zone around stars by many orders of magnitude.

    The adaptation of life to extreme environments could take exotic forms, as exemplified by extremophiles on Earth. For example, frozen microscopic animals were recently discovered [Current Biology] to survive 24,000 years in the Siberian permafrost, and microbial life was found to persist 100 million years beneath the seafloor. These microbes were born during the warm Cretaceous period when dinosaurs dominated the Earth.

    In the solar system, the closest conditions to Earth were realized on its nearest neighbors, Venus and Mars. NASA recently selected two new missions to study Venus, and its Perseverance rover is searching for traces of life on Mars. If extraterrestrial life is found, the key follow-up question is whether it is “life as we know it.” If not, we will realize that there are multiple chemical pathways to natural life. But if we find evidence for Martian or Venusian life that resembles terrestrial life, then this might indicate a special preference for “life as we know it.” Alternatively, life could have been transported by rocks that traveled between planets through a process called panspermia. My student Amir Siraj and I wrote a paper showing that the transfer of life could have been mediated by planet-grazing asteroids. We should also keep in mind the very remote possibility that life was seeded in the inner solar system by an “extrasolar gardener,” namely through “directed panspermia”.

    My most vivid childhood memory is of dinner conversations in which the adults in the room pretended to know much more than they actually did. This was undoubtedly a form of “intellectual makeup” that they wore to improve their appearance. And if I asked a question to which these pretenders had no ready answer, they would dismiss it as irrelevant. My experience as a senior scientist is no different, especially when asking the question: “Are we the smartest kid on the cosmic block?”

    Science offers the privilege of maintaining our childhood curiosity. The advance of scientific knowledge through experimentation cannot be stopped. Here’s hoping that we will find a recipe for artificial life that will allow us to imagine something far more intelligent than the natural life we encountered so far. This will be a humbling experience. But even if we will not discover this supreme intelligence in our laboratories, its by-products may just show up in our sky as mail posted from faraway neighborhoods in the Milky Way. And we’ll be searching for that through the telescopes of the recently announced Galileo Project.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    Scientific American (US) , the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

     
  • richardmitnick 9:06 am on December 8, 2020 Permalink | Reply
    Tags: "Using Earth’s history to inform the search for life on exoplanets", Astrobiology, , , , , How to detect planets that could host life and remain habitable despite tremendous change over time., Humans will likely never visit exoplanets- at least not soon., Our research focuses on diverse chapters of Earth’s history-or alternative Earths-that span billions of years and offer critical templates for examining exoplanets far beyond our solar system., RCNs-Research Coordination Networks, Studying biosignature gases in Earth’s past will allow the team to design telescopes and refine interpretative models for potential traces of life in distant exoplanet atmospheres., Success in this mission will require biological; chemical; geological; oceanographic and astronomical expertise.,   

    From UC Riverside: “Using Earth’s history to inform the search for life on exoplanets” 

    UC Riverside bloc

    From UC Riverside

    December 8, 2020

    Jules L Bernstein
    Senior Public Information Officer
    (951) 827-4580
    jules.bernstein@ucr.edu

    1
    UC Riverside-led team looks back to find life beyond. UC Riverside.

    2
    This image shows an Earth-like “exomoon” orbiting a gas giant planet in a star’s habitable zone. Credit: NASA/JPL-Caltech.

    UC Riverside is leading one of the NASA Astrobiology Program’s eight new research teams tackling questions about the evolution and origins of life on Earth and the possibility of life beyond our solar system.

    The teams comprise the inaugural class of NASA’s Interdisciplinary Consortia for Astrobiology Research program. The UCR-led team is motivated by the fundamental question of how to detect planets that could host life and remain habitable despite tremendous change over time, which requires hunting for biological gases in the atmospheres of planets light years beyond our solar system.

    “To achieve this goal, our research focuses on the many diverse chapters of Earth’s history — or alternative Earths — that span billions of years and offer critical templates for examining exoplanets far beyond our solar system,” said UCR biogeochemist Timothy Lyons, the project leader.

    Because of their immense distance from us, humans will likely never visit those planets, at least not soon, Lyons said. However, in the near future, scientists will be able to analyze the compositions of these planets’ atmospheres, looking for gases like oxygen and methane that could come from life.

    Earth has undergone dramatic changes over the last 4.5 billion years, with major transitions occurring in plate tectonics, climate, ocean chemistry, the structure of our ecosystems, and composition of our atmosphere.

    “These changes represent an opportunity,” Lyons said. “The different periods of Earth’s evolutionary history provide glimpses of many, largely alien worlds, some of which may be analogs for habitable planetary states that are very different from conditions on modern Earth.”

    Exciting new research frontiers for Lyons’ team include studies of Earth’s first 500 million years, as well as predictions about our planet and its life billions of years in the future.

    Studying biosignature gases in Earth’s past will allow the team to design telescopes and refine interpretative models for potential traces of life in distant exoplanet atmospheres, noted Georgia Tech biogeochemist Christopher Reinhard.

    Once the researchers understand how Earth and its star — the sun — changed together to maintain liquid oceans teeming with life over billions of years, the team can predict how other planetary systems might also have developed and maintained life and better understand how to search for it.

    “Such a ‘mission to early Earth’ must include broad interdisciplinarity within the team, impactful synergy within and across the Research Coordination Networks, or RCNs, of the NASA Astrobiology Program, and a commitment to deliverables that will help steer NASA science for decades to come,” said UCR astrobiologist Edward Schwieterman.

    Success in this mission will require biological, chemical, geological, oceanographic, and astronomical expertise. Yale University biogeochemist Noah Planavsky said, “our team brings all that to the table.” Accordingly, the diverse expertise within the team includes astronomers, planetary scientists, geologists, geophysicists, oceanographers, biogeochemists, and geobiologists.

    The team will collect ancient rock samples and modern sediments from around the world spanning billions of years and use the data they generate to drive wide-ranging computational models for Earth’s ancient and future oceans and atmospheres.

    “The models will allow the team to evaluate whether different periods in Earth’s history were characterized by gases that would have been detectable from a distant vantage as products of life, much the way oxygen fingerprints life on our planet today,” said Purdue University Earth and exoplanetary scientist Stephanie Olson.

    This work requires a multipronged view of the Earth as a complex system that has varied dramatically over time. Yet despite all the change, Earth has remained persistently habitable, with liquid water oceans teeming with life.

    How Earth became and remained habitable and whether its life would have been detectable to a distant observer are the questions that will ultimately define and refine the search for life on exoplanets.

    “In short,” said Lyons, “the exciting goal of our team is to provide a new and more holistic view of Earth’s evolutionary history in order to help guide NASA’s mission-specific search for life on distant worlds.”

    The RCNs are the new face of astrobiology at NASA, following 20 years of exciting research under the umbrella of the NASA Astrobiology Institute, which supported the UCR-led team previously.

    The $4.6 million new award from NASA will span five years and includes team members from Georgia Tech, Yale University, Purdue University, UCLA, NASA Ames Research Center and collaborators from around the world.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 12:07 pm on November 17, 2020 Permalink | Reply
    Tags: "UC Santa Cruz leads interdisciplinary consortium for astrobiology research", Astrobiology, , , , ,   

    From UC Santa Cruz: “UC Santa Cruz leads interdisciplinary consortium for astrobiology research” 

    From UC Santa Cruz

    November 16, 2020
    Tim Stephens
    stephens@ucsc.edu

    With funding from NASA, the UCSC-led team will lay the foundation for detecting the signatures of life in the atmospheres of other planets.

    1
    Follow the Volatiles: The new consortium will trace chemical species relevant to habitability from star-forming clouds to exoplanet atmospheres. Credit: Dina Clark.

    The NASA Astrobiology Program has awarded a five-year, $5 million grant to an interdisciplinary consortium led by the University of California, Santa Cruz, to trace the volatile elements that form the atmospheres of planets, establishing a scientific foundation for detecting the signatures of life on other worlds.

    Natalie Batalha, professor of astronomy and astrophysics at UC Santa Cruz, will lead the consortium, one of eight new research teams selected by NASA to inaugurate its Interdisciplinary Consortia for Astrobiology Research (ICAR) program. In addition to UCSC, the consortium includes researchers at the University of Hawaii at Manoa, University of Colorado, Boulder, University of Kansas, and NASA Ames Research Center.

    “We want to understand the physical processes that impact planetary atmospheres,” Batalha said. “We must understand those physical processes and their effects in the absence of life so that we will be able to recognize the signs of life when we see them.”

    Batalha served as the project scientist for NASA’s highly successful Kepler Mission, which discovered more than 2,500 exoplanets. A recent analysis of Kepler data suggests there are at least 300 million potentially habitable worlds in our galaxy. Batalha noted, however, that a planet in the “habitable zone” of its star (where liquid water could pool on the planet’s surface) is not guaranteed to be a truly habitable environment.

    “One of the takeaways from the Kepler Mission is that the diversity of exoplanets in the galaxy far exceeds the diversity of our own solar system,” she said. “If we want to understand the diversity of rocky, habitable zone planets, we have to study the physical processes that sculpt the atmospheres of all planets—even those not amenable to life as we know it.”

    For Batalha’s team, that means “following the volatiles,” tracing the path of the volatile elements like carbon and oxygen that make up a planet’s atmosphere. That path goes from star-forming clouds into protoplanetary disks, to the building blocks of planets, and eventually into planets themselves, where volatile elements can move between the surface, atmosphere, and interior, and even be lost to space.

    The launch of the James Webb Space Telescope (JWST) in 2021 will usher in a new era of exoplanet exploration and the characterization of exoplanet atmospheres. The consortium will develop the tools needed to interpret observations of exoplanet atmospheres made by JWST and the latest generation of ground-based telescopes.

    The researchers will address four fundamental science questions: What is the inventory of volatiles in planetary building blocks? What are a planet’s external sources and sinks of volatiles (in other words, where do they come from and where do they go)? How are volatiles distributed between a planet’s interior, surface, and atmosphere? And what can atmospheric observations tell us about the volatile inventories and chemistries of exoplanets?

    Researchers at the University of Hawaii led by Eric Gaidos will investigate the formation of planets and their volatile content using astronomical observations of protoplanetary disks and young planets, laboratory experiments that simulate conditions in the interiors of planetesimals and growing planets, and analysis of meteorites and samples returned from asteroids.

    Meredith MacGregor at the University of Colorado, Boulder, will lead analysis of circumstellar disk observations using the Atacama Large Millimeter/submillimeter Array (ALMA) combined with other ground-based observatories. She will also coordinate multi-wavelength observing campaigns to explore the properties of and mechanisms behind stellar flaring in order to better understand how these events can damage planetary atmospheres over time.

    Ian Crossfield at the University of Kansas will lead isotopic abundance analyses of exoplanets, brown dwarfs, and dwarf stars. He will also consult and assist with the planning and analysis of Hubble Space Telescope and JWST spectroscopy of nearby exoplanets. Thomas Greene is leading the effort at NASA Ames Research Center to provide guaranteed-time JWST observations of exoplanet atmospheres and model their chemical abundances, clouds, and photochemical effects.

    “Our team has a broad range of expertise and unparalleled access to the telescopes and facilities needed to carry out this research and meet the challenge of not just finding life on other worlds, but having confidence that we can identify signatures of life when we see them,” Batalha said.

    At UC Santa Cruz, the team includes faculty in two departments, Astronomy & Astrophysics and Earth & Planetary Sciences (EPS). Jonathan Fortney, professor of astronomy and astrophysics and director of the Other Worlds Laboratory, will conduct theoretical and modeling work on exoplanet structure and atmospheres; Ruth Murray-Clay, the Gunderson Professor of Theoretical Astrophysics, will conduct a wide array of theoretical work, including the physics of disk structure and evolution and the processes of atmospheric mass loss.

    Francis Nimmo, professor of EPS, will model planetesimal volatile acquisition and retention; Myriam Telus, assistant professor of EPS, will study meteorite outgassing and cosmochemistry; and Xi Zhang, assistant professor of EPS, will model exoplanet atmospheres and help interpret exoplanet spectra in the context of cloud physics. Andrew Skemer, associate professor of astronomy and astrophysics, and Rebecca Jensen-Clem, assistant professor of astronomy and astrophysics, will also contribute to the consortium.

    Batalha, who leads UCSC’s interdisciplinary Astrobiology Initiative, said the NASA ICAR award is a testament to the strength of UCSC’s faculty in this area of research.

    “I came to UC Santa Cruz knowing that the pieces were in place already for a strong astrobiology program. This funding allows us build on that foundation and means that astrobiology at UCSC can flourish,” she said.

    The UCSC Office of Research provided seed funding for the Astrobiology Initiative.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Observatories Lick Automated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA.

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Santa Cruz campus.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory’s 36-inch Great Great Refractor telescope housed in the South (large) Dome of main building.

     
  • richardmitnick 11:14 am on November 14, 2020 Permalink | Reply
    Tags: "Tree rings may hold clues to earthly impacts of distant supernovas", Astrobiology, , , , ,   

    From University of Colorado Boulder : “Tree rings may hold clues to earthly impacts of distant supernovas” 

    U Colorado

    From University of Colorado Boulder

    Nov. 11, 2020
    Daniel Strain

    1
    The remnants of a supernova in the Large Magellanic Cloud, a dwarf galaxy that sits close to the Milky Way. Credit: NASA/ESA/HEIC and The Hubble Heritage Team.

    Massive explosions of energy happening thousands of light-years from Earth may have left traces in our planet’s biology and geology, according to new research by CU Boulder geoscientist Robert Brakenridge.

    The study, published this month in the International Journal of Astrobiology, probes the impacts of supernovas, some of the most violent events in the known universe. In the span of just a few months, a single one of these eruptions can release as much energy as the sun will during its entire lifetime. They’re also bright—really bright.

    “We see supernovas in other galaxies all the time,” said Brakenridge, a senior research associate at the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder. “Through a telescope, a galaxy is a little misty spot. Then, all of a sudden, a star appears and may be as bright as the rest of the galaxy.”

    A very nearby supernova could be capable of wiping human civilization off the face of the Earth. But even from farther away, these explosions may still take a toll, Brakenridge said, bathing our planet in dangerous radiation and damaging its protective ozone layer.

    To study those possible impacts, Brakenridge searched through the planet’s tree ring records for the fingerprints of these distant, cosmic explosions. His findings suggest that relatively close supernovas could theoretically have triggered at least four disruptions to Earth’s climate over the last 40,000 years.

    3
    A bubble of gas expanding at roughly 11 million miles per hour created by the shockwave from a supernova. Credit: NASA.

    The results are far from conclusive, but they offer tantalizing hints that, when it comes to the stability of life on Earth, what happens in space doesn’t always stay in space.

    “These are extreme events, and their potential effects seem to match tree ring records,” Brakenridge said.

    Radiocarbon spikes

    His research hinges on the case of a curious atom. Brakenridge explained that carbon-14, also known as radiocarbon, is a carbon isotope that occurs only in tiny amounts on Earth. It’s not from around here, either. Radiocarbon is formed when cosmic rays from space bombard our planet’s atmosphere on an almost constant basis.

    “There’s generally a steady amount year after year,” Brakenridge said. “Trees pick up carbon dioxide and some of that carbon will be radiocarbon.”

    Sometimes, however, the amount of radiocarbon that trees pick up isn’t steady. Scientists have discovered a handful of cases in which the concentration of this isotope inside tree rings spikes—suddenly and for no apparent earthly reason. Many scientists have hypothesized that these several-year-long spikes could be due to solar flares or huge ejections of energy from the surface of the sun.

    Brakenridge and a handful of other researchers have had their eye on events much farther from home.

    “We’re seeing terrestrial events that are begging for an explanation,” Brakenridge said. “There are really only two possibilities: A solar flare or a supernova. I think the supernova hypothesis has been dismissed too quickly.”

    Beware Betelgeuse

    Betelgeuse, in the infrared from the Herschel Space Observatory, is a superluminous red giant star 650 light-years away. Stars much more massive, like Betelgeuse, end their lives as supernova.Credit: ESA/Herschel/PACS/L. Decin et al.

    He noted that scientists have recorded supernovas in other galaxies that have produced a stupendous amount of gamma radiation—the same kind of radiation that can trigger the formation of radiocarbon atoms on Earth. While these isotopes aren’t dangerous on their own, a spike in their levels could indicate that energy from a distant supernova has traveled hundreds to thousands of light-years to our planet.

    To test the hypothesis, Brakenridge turned to the past. He assembled a list of supernovas that occurred relatively close to Earth over the last 40,000 years. Scientists can study these events by observing the nebulas they left behind. He then compared the estimated ages of those galactic fireworks to the tree ring record on the ground.

    He found that of the eight closest supernovas studied, all seemed to be associated with unexplained spikes in the radiocarbon record on Earth. He considers four of these to be especially promising candidates. Take the case of a former star in the Vela constellation. This celestial body, which once sat about 815 light-years from Earth, went supernova roughly 13,000 years ago. Not long after that, radiocarbon levels jumped up by nearly 3% on Earth—a staggering increase.

    The findings aren’t anywhere close to a smoking gun, or star, in this case. Scientists still have trouble dating past supernovas, making the timing of the Vela explosion uncertain with a possible error of as much as 1,500 years. It’s also not clear what the impacts of such a disruption might have been for plants and animals on Earth at the time. But Brakenridge believes that the question is worth a lot more research.

    “What keeps me going is when I look at the terrestrial record and I say, ‘My God, the predicted and modeled effects do appear to be there.’”

    He hopes that humanity won’t have to see those effects for itself anytime soon. Some astronomers think they’ve picked up signs that Betelgeuse, a red giant star in the constellation Orion, might be on the verge of collapsing and going supernova. And it’s only 642.5 light-years from Earth, much closer than Vela.

    “We can hope that’s not what’s about to happen because Betelgeuse is really close,” he said said.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Colorado Campus

    As the flagship university of the state of Colorado CU-Boulder is a dynamic community of scholars and learners situated on one of the most spectacular college campuses in the country. As one of 34 U.S. public institutions belonging to the prestigious Association of American Universities (AAU) – and the only member in the Rocky Mountain region – we have a proud tradition of academic excellence, with five Nobel laureates and more than 50 members of prestigious academic academies.

    CU-Boulder has blossomed in size and quality since we opened our doors in 1877 – attracting superb faculty, staff, and students and building strong programs in the sciences, engineering, business, law, arts, humanities, education, music, and many other disciplines.

    Today, with our sights set on becoming the standard for the great comprehensive public research universities of the new century, we strive to serve the people of Colorado and to engage with the world through excellence in our teaching, research, creative work, and service.

     
  • richardmitnick 12:24 pm on November 10, 2020 Permalink | Reply
    Tags: "Radioactive elements may be crucial to the habitability of rocky planets", Astrobiology, , , , , Geodynamo-an internal dynamo that generates the planet’s magnetic field., Heavy elements crucial to radiogenic heating are created during mergers of neutron stars., It has long been speculated that internal heating drives plate tectonics., , Radioactive elements power geological activity and the magnetic field., Radiogenic heating, The lack of a magnetic field is apparently part of the reason along with its lower gravity why Mars has a very thin atmosphere.,   

    From UC Santa Cruz: “Radioactive elements may be crucial to the habitability of rocky planets” 

    From UC Santa Cruz

    November 10, 2020
    Tim Stephens
    stephens@ucsc.edu

    Earth-size planets can have varying amounts of radioactive elements, which generate internal heat that drives a planet’s geological activity and magnetism.

    1
    These illustrations show three versions of a rocky planet with different amounts of internal heating from radioactive elements. The middle planet is Earth-like, with plate tectonics and an internal dynamo generating a magnetic field. The top planet, with more radiogenic heating, has extreme volcanism but no dynamo or magnetic field. The bottom planet, with less radiogenic heating, is geologically “dead,” with no volcanism. Credit: Melissa Weiss.

    The amount of long-lived radioactive elements incorporated into a rocky planet as it forms may be a crucial factor in determining its future habitability, according to a new study by an interdisciplinary team of scientists at UC Santa Cruz.

    That’s because internal heating from the radioactive decay of the heavy elements thorium and uranium drives plate tectonics and may be necessary for the planet to generate a magnetic field. Earth’s magnetic field protects the planet from solar winds and cosmic rays.

    Convection in Earth’s molten metallic core creates an internal dynamo (the “geodynamo”) that generates the planet’s magnetic field. Earth’s supply of radioactive elements provides more than enough internal heating to generate a persistent geodynamo, according to Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz and first author of a paper on the new findings, published November 10 in The Astrophysical Journal Letters.

    “What we realized was that different planets accumulate different amounts of these radioactive elements that ultimately power geological activity and the magnetic field,” Nimmo explained. “So we took a model of the Earth and dialed the amount of internal radiogenic heat production up and down to see what happens.”

    What they found is that if the radiogenic heating is more than the Earth’s, the planet can’t permanently sustain a dynamo, as Earth has done. That happens because most of the thorium and uranium end up in the mantle, and too much heat in the mantle acts as an insulator, preventing the molten core from losing heat fast enough to generate the convective motions that produce the magnetic field.

    With more radiogenic internal heating, the planet also has much more volcanic activity, which could produce frequent mass extinction events. On the other hand, too little radioactive heat results in no volcanism and a geologically “dead” planet.

    “Just by changing this one variable, you sweep through these different scenarios, from geologically dead to Earth-like to extremely volcanic without a dynamo,” Nimmo said, adding that these findings warrant more detailed studies.

    “Now that we see the important implications of varying the amount of radiogenic heating, the simplified model that we used should be checked by more detailed calculations,” he said.

    Habitability

    A planetary dynamo has been tied to habitability in several ways, according to Natalie Batalha, a professor of astronomy and astrophysics whose Astrobiology Initiative at UC Santa Cruz sparked the interdisciplinary collaboration that led to this paper.

    “It has long been speculated that internal heating drives plate tectonics, which creates carbon cycling and geological activity like volcanism, which produces an atmosphere,” Batalha explained. “And the ability to retain an atmosphere is related to the magnetic field, which is also driven by internal heating.”

    Coauthor Joel Primack, a professor emeritus of physics, explained that stellar winds, which are fast-moving flows of material ejected from stars, can steadily erode a planet’s atmosphere if it has no magnetic field.

    “The lack of a magnetic field is apparently part of the reason, along with its lower gravity, why Mars has a very thin atmosphere,” he said. “It used to have a thicker atmosphere, and for a while it had surface water. Without the protection of a magnetic field, much more radiation gets through and the surface of the planet also becomes less habitable.”

    Primack noted that the heavy elements crucial to radiogenic heating are created during mergers of neutron stars, which are extremely rare events. The creation of these so-called r-process elements during neutron-star mergers has been a focus of research by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics.

    “We would expect considerable variability in the amounts of these elements incorporated into stars and planets, because it depends on how close the matter that formed them was to where these rare events occurred in the galaxy,” Primack said.

    Astronomers can use spectroscopy to measure the abundance of different elements in stars, and the compositions of planets are expected to be similar to those of the stars they orbit. The rare earth element europium, which is readily observed in stellar spectra, is created by the same process that makes the two longest-lived radioactive elements, thorium and uranium, so europium can be used as a tracer to study the variability of those elements in our galaxy’s stars and planets.

    Natural range

    Astronomers have obtained europium measurements for many stars in our galactic neighborhood. Nimmo was able use those measurements to establish a natural range of inputs to his models of radiogenic heating. The sun’s composition is in the middle of that range. According to Primack, many stars have half as much europium compared to magnesium as the sun, and many stars have up to two times more than the sun.

    The importance and variability of radiogenic heating opens up many new questions for astrobiologists, Batalha said.

    “It’s a complex story, because both extremes have implications for habitability. You need enough radiogenic heating to sustain plate tectonics but not so much that you shut down the magnetic dynamo,” she said. “Ultimately, we’re looking for the most likely abodes of life. The abundance of uranium and thorium appear to be key factors, possibly even another dimension for defining a Goldilocks planet.”

    Using europium measurements of their stars to identify planetary systems with different amounts of radiogenic elements, astronomers can start looking for differences between the planets in those systems, Nimmo said, especially once the James Webb Space Telescope is deployed. “The James Webb Space Telescope will be a powerful tool for the characterization of exoplanet atmospheres,” he said.

    In addition to Nimmo, Primack, and Ramirez-Ruiz, the coauthors of the paper include Sandra Faber, professor emerita of astronomy and astrophysics, and postdoctoral scholar Mohammadtaher Safarzadeh.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Observatories Lick Automated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA.

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Santa Cruz campus.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory’s 36-inch Great Great Refractor telescope housed in the South (large) Dome of main building.

     
  • richardmitnick 11:44 pm on November 9, 2020 Permalink | Reply
    Tags: "Life on Ancient Earth and Alien Planets- UArizona to Lead NASA Astrobiology Projects", , Astrobiology, , , , ,   

    From University of Arizona: “Life on Ancient Earth and Alien Planets- UArizona to Lead NASA Astrobiology Projects” 

    From University of Arizona

    11.9.20
    Daniel Stolte
    Science Writer, University Communications
    stolte@arizona.edu
    520-626-4402

    Daniel Apai
    Steward Observatory
    apai@as.arizona.edu
    520-621-6534

    Betül Kaçar
    Department of Astronomy
    Department of Molecular and Cellular Biology
    Department of Planetary Sciences
    betul@arizona.edu

    NASA awarded approximately $12 million to UArizona astrobiology researchers to establish two major new research teams tasked with advancing our fundamental understanding of early Earth biology and biogeochemistry, and with exploring which nearby planets outside our solar system may be suitable for hosting life.

    1
    The NASA Astrobiology Program has selected eight new interdisciplinary research teams to inaugurate its Interdisciplinary Consortia for Astrobiology Research program, including two teams at the University of Arizona. Led by Betül Kaçar and Dániel Apai, the teams were selected from a pool of more than 40 proposals. The breadth and depth of the research of these teams spans the spectrum of astrobiology research, from cosmic origins to planetary system formation, origins and evolution of life, and the search for life beyond Earth.

    The two ICAR grants total approximately $12 million.

    “Being part of this inaugural effort will position the University of Arizona in a leading role at the forefront of the most pressing and challenging questions in astrobiology,” said University of Arizona President Robert C. Robbins. “It is an incredible honor to have two teams from the university selected for this important work and I look forward to following their progress in this groundbreaking research.”

    Astrobiology is a discipline devoted to the study of the origins, evolution and distribution of life in the universe, the declared goal of NASA’s Astrobiology Program. The program is central to NASA’s continued exploration of the solar system and beyond, and supports research into the origin and early evolution of life, the potential of life to adapt to different environments, and the implications for life elsewhere.

    Kaçar’s ICAR project team is named Metal Utilization and Selection Across Eons, or MUSE, and will explore “What Life Wants: Exploring the Natural Selection of Elements,” which focuses on a question fundamental to the field of astrobiology as a whole, she said.

    “What are the essential attributes of life, and how should they shape our notions of habitability and the search for life on other worlds?” Kaçar said. Motivated by this broad question, her project team will explore the natural selection of the chemical elements during the coevolution of life and environment on Earth.

    “We will connect earth sciences with astronomy and biology, using tools drawn from synthetic biology, genomics and evolution, as well as geochemistry and biochemistry, to pioneer an entirely new scientific discipline – ‘evolutionary metallomics’ – studying the evolution of metal use in biological pathways, particularly the biological nitrogen cycle.”

    2
    Rewinding the tape of evolution: Betül Kaçar’s group explores the evolution of reconstructed ancient proteins and why life on Earth chose the chemical elements it did.

    Kaçar’s research program will cultivate a new cohort of scientists with experimental and analytical expertise who can combine earth and life science disciplines to inform astrobiology search strategies. Being able to tease apart the essential attributes of life would have a direct impact on scientists’ ideas of habitability and the search for life on other worlds.

    “While we have learned a tremendous amount about how nature uses these elements in the biochemistry of organisms, there remains deep uncertainty about why evolution selected for these elements,” she said. “In other words, what does life want, and why does it want what it wants?”

    Kaçar’s team will approach this puzzle by studying life on early Earth. This will involve geochemical and biological investigations that involve ancient materials, experiments and modern natural systems, such as tracking down microbes in extreme environments and remote locations, as well as studying ancient variants of proteins and microbial metabolisms in the lab.

    “ICAR will allow us to rewind the evolutionary clock in the laboratory, and explore the evolution of reconstructed ancient proteins, and experimentally study their characteristics,” Kaçar said. “We look forward to supporting NASA’s Science Mission Directorate on priority astrobiology goals.”

    The project will bring together earth scientists and life scientists in a unique, problem-focused collaboration closely aligned with NASA’s strategies, Kaçar said.

    “It is easy to see on Earth today that life depends on certain elements,” she said. “We want to study whether this dependence is an inevitable consequence of the elements available to life, or whether it is an accident of history that might have worked out very differently if we replayed the tape of evolution under slightly different conditions – as seems inevitable on other worlds.”

    Apai is an associate professor in the UArizona departments of astronomy and planetary sciences, and Kaçar is an assistant professor with joint appointments in the departments of molecular and cellular biology and astronomy and planetary sciences. She also is a member of UArizona’s BIO5 Institute.

    The team led by Apai, “Alien Earths,” is poised to transform scientists’ understanding of the habitability of nearby planetary systems. Alien Earths will carry out 14 closely coordinated research projects, including theoretical, laboratory analysis and observational studies.

    Recent discoveries suggest that habitable planets may be very common, Apai said, which begs the question, “Which nearby planetary systems are likely to host habitable planets and possibly life?” NASA and the astrobiology community are working on ideas for powerful next-generation space telescopes that could scan the atmospheres of nearby planets for gases that indicate the presence of life.

    “Earthlike planets remain very difficult to find and, even more so, to characterize,” Apai said. “Our team will help assess which nearby planetary systems are more likely to be good targets, an essential step in defining the optimal strategy for our search for life in the universe.”

    3
    Searching for alien Earths: The work of Daniel Apai’s team is poised to inform future NASA missions that search for life on other worlds. Credit: Marton Apai.

    Apai’s ICAR grant builds on and extends a major research program led by his group called “Earths in Other Solar Systems,” or EOS, a five-year program that led to more than 140 refereed scientific papers and is now in its final year of funding. EOS is dedicated to finding out how habitable planets form, and the new ICAR project will take those insights, complement them with new projects, and apply the combined knowledge to nearby planets to investigate which ones may be suitable for life, Apai said.

    “Like EOS, Alien Earths will not only be a fascinating research program,” Apai said. “We defined it strategically to closely tie into upcoming and next-generation NASA exoplanet missions, with the goal to inform, guide and enhance the capabilities of future NASA missions that search for life on other worlds.”

    The NASA ICAR award is critically important to launch the work of the Alien Earths team, a team of more than 50 undergraduate and graduate students, plus junior and senior researchers from seven countries. The team will form a powerful, international, multidisciplinary hub for the exploration of habitable planetary systems.

    Both projects will include interdisciplinary collaborations within UArizona, connecting Steward Observatory and the Lunar and Planetary Laboratory, with the departments of molecular and cellular biology, chemistry and biochemistry, computer science, ecology and evolutionary biology, and the BIO5 Institute.

    “The University of Arizona has deep, unparalleled expertise and decades-long tradition in space science, and, perhaps now more than ever, we are focused on leading ambitious, imaginative research programs that leverage our unique capabilities while bringing together talented scientists from across the state and nation,” said Elizabeth “Betsy” Cantwell, senior vice president for research and innovation. “Drs. Kaçar and Apai’s astrobiological research is absolutely demonstrative of that effort.”

    The Alien Earths team is led by the University of Arizona and includes the following partner institutions: Arizona State University; the Massachusetts Institute of Technology; NSF’s National Optical-Infrared Astronomy Research Laboratory; the University of Chicago; Adolfo Ibáñez University (CL); Bern University (CH); Lund University (SE); Paris Observatory (FR); the University of Exeter (UK); and Xiamen University (CN).

    Kaçar’s project is a first of its kind and includes the following partner institutions:
    Arizona State University; Stanford University; Utah State University; the University of Minnesota; the University of Tennessee, Knoxville; Iowa State University; and the University of Alberta (CA).

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of Arizona (UA) is a place without limits-where teaching, research, service and innovation merge to improve lives in Arizona and beyond. We aren’t afraid to ask big questions, and find even better answers.

    In 1885, establishing Arizona’s first university in the middle of the Sonoran Desert was a bold move. But our founders were fearless, and we have never lost that spirit. To this day, we’re revolutionizing the fields of space sciences, optics, biosciences, medicine, arts and humanities, business, technology transfer and many others. Since it was founded, the UA has grown to cover more than 380 acres in central Tucson, a rich breeding ground for discovery.

    U Arizona mirror lab-Where else in the world can you find an astronomical observatory mirror lab under a football stadium?

    University of Arizona’s Biosphere 2, located in the Sonoran desert. An entire ecosystem under a glass dome? Visit our campus, just once, and you’ll quickly understand why the UA is a university unlike any other.

     
  • richardmitnick 1:29 pm on October 7, 2020 Permalink | Reply
    Tags: "New research explores how super flares affect planets’ habitability", Astrobiology, , , , , Evryscope South telescope at NOIRLab CTIO in Chile, Researchers from UNC-Chapel Hill have for the first time measured the temperature of a large sample of super flares from stars and the flares’ likely ultraviolet emissions., Ultraviolet light from giant stellar flares can destroy a planet’s habitability.,   

    From University of North Carolina-Chapel Hill: “New research explores how super flares affect planets’ habitability” 

    From University of North Carolina-Chapel Hill

    October 7th, 2020

    UNC-Chapel Hill and NASA measure temperature for the largest ever sample of super flares.

    1
    The Evryscope South dome overlooks the Pacific from NOIRLab CTIO in Chile, one of the driest places with the clearest skies on Earth. Many dark cloudless nights give the system over 6 hours of simultaneous observing time each night alongside NASA’s TESS space telescope to hunt for flares Credit: UNC-Chapel Hill

    NASA/MIT TESS replaced Kepler in search for exoplanets.

    Ultraviolet light from giant stellar flares can destroy a planet’s habitability. New research from the University of North Carolina at Chapel Hill will help astrobiologists understand how much radiation planets experience during super flares and whether life could exist on worlds beyond our solar system.

    Super flares are bursts of energy that are 10 to 1,000 times larger than the biggest flares from the Earth’s sun. These flares can bathe a planet in an amount of ultraviolet light huge enough to doom the chances of life surviving there.

    Researchers from UNC-Chapel Hill have for the first time measured the temperature of a large sample of super flares from stars, and the flares’ likely ultraviolet emissions. Their findings, published Oct. 5 ahead of print in The Astrophysical Journal [EvryFlare III: Temperature Evolution and Habitability Impacts of Dozens of Superflares Observed Simultaneously by Evryscope and TESS], will allow researchers to put limits on the habitability of planets that are targets of upcoming planet-finding missions.

    “We found planets orbiting young stars may experience life-prohibiting levels of UV radiation, although some micro-organisms might survive,” said lead study author Ward S. Howard, a doctoral student in the Department of Physics and Astronomy at UNC-Chapel Hill.

    Howard and colleagues at UNC-Chapel Hill used the UNC-Chapel Hill Evryscope telescope array and NASA’s Transiting Exoplanet Survey Satellite (TESS) to simultaneously observe the largest sample of super flares.

    The team’s research expands upon previous work that has largely focused on flare temperatures and radiation from only a handful of super flares from a few stars. In expanding the research, the team discovered a statistical relationship between the size of a super flare and its temperature. The temperature predicts the amount of radiation that potentially precludes on-surface life.

    Super flares typically emit most of their UV radiation during a rapid peak lasting only five to 15 minutes. The simultaneous Evryscope and TESS observations were obtained at two-minute intervals, ensuring multiple measurements were taken during the peak of each super flare.

    This is the first time the temperatures of such a large sample of super flares has ever been studied. The frequency of observations allowed the team to discover the amount of time super flares can cook orbiting planets with intense UV radiation.

    The flares observed have already informed the TESS Extended Mission to discover thousands of exoplanets in orbit around the brightest dwarf stars in the sky. TESS is now targeting high priority flare stars from the UNC-Chapel Hill sample for more frequent observations.

    “Longer term these results may inform the choice of planetary systems to be observed by NASA’s James Webb Space Telescope based on the system’s flaring activity,” said study co-author Nicholas M. Law, associate professor of physics and astronomy at UNC-Chapel Hill and principal investigator of the Evryscope telescope.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    UNC-University of North Carolina-Chapel Hill
    Carolina’s vibrant people and programs attest to the University’s long-standing place among leaders in higher education since it was chartered in 1789 and opened its doors for students in 1795 as the nation’s first public university. Situated in the beautiful college town of Chapel Hill, N.C., UNC has earned a reputation as one of the best universities in the world. Carolina prides itself on a strong, diverse student body, academic opportunities not found anywhere else, and a value unmatched by any public university in the nation.

     
  • richardmitnick 11:37 am on October 4, 2020 Permalink | Reply
    Tags: "Life on Earth may have begun in hostile hot springs", Astrobiology, , , Understanding how complex molecules formed on our planet could guide the search for life elsewhere in the solar system.   

    From Science News: “Life on Earth may have begun in hostile hot springs” 

    From Science News

    September 24, 2020
    Jack J. Lee

    1
    Hot springs, like those at Lassen Volcanic National Park’s Bumpass Hell in California, provide conditions that may have supported life as it began on Earth. Credit: Blake Smith.

    Understanding how complex molecules formed on our planet could guide the search for life elsewhere in the solar system.

    At Bumpass Hell in California’s Lassen Volcanic National Park, the ground is literally boiling, and the aroma of rotten eggs fills the air. Gas bubbles rise through puddles of mud, producing goopy popping sounds. Jets of scorching-hot steam blast from vents in the earth. The fearsome site was named for the cowboy Kendall Bumpass, who in 1865 got too close and stepped through the thin crust. Boiling, acidic water burned his leg so badly that it had to be amputated.

    Some scientists contend that life on our planet arose in such seemingly inhospitable conditions [Astrobiology]. Long before creatures roamed the Earth, hot springs like Bumpass Hell may have promoted chemical reactions that linked together simple molecules in a first step toward complexity. Other scientists, however, place the starting point for Earth’s life underwater, at the deep hydrothermal vents where heated, mineral-rich water billows from cracks in the ocean floor.

    As researchers study and debate where and how life on Earth first ignited, their findings offer an important bonus. Understanding the origins of life on this planet could offer hints about where to search for life elsewhere, says Natalie Batalha, an astrophysicist at the University of California, Santa Cruz. “It has very significant implications for the future of space exploration.” Chemist Wenonah Vercoutere agrees. “The rules of physics are the same throughout the whole universe,” says Vercoutere, of NASA’s Ames Research Center in Moffett Field, Calif. “So what is there to say that the rules of biology do not also carry through and are in place and active in the whole universe?”

    2
    At Bumpass Hell hot spring, cycles of wetting and drying at the edges of the geothermal pools are thought to promote the assembly of biomolecules. Credit: Joe Benning/Alamy Stock Photo.

    Lure of the land

    At its biochemical core, the recipe for life relies on only a few ingredients: chemical elements, water or other media where chemical reactions can occur and an energy source to power those reactions. On Earth, all of those ingredients exist at terrestrial hot springs, home to some hardy creatures. Great Boiling Spring in Nevada, for example, is a scalding 77° Celsius, yet microbes manage to eke out an existence in water near the spring’s clay banks, researchers reported in 2016 in Nature Communications. Such conditions may reflect what it was like on early Earth, so these life-forms are most likely “related to some of the organisms that were originally on this planet,” says Jennifer Pett-Ridge, a microbial ecologist at Lawrence Livermore National Laboratory in California.

    Microorganisms at hot springs can form communities called microbial mats. Made up of layers of microbes, mats have been found in geothermal areas all over the world, including in Yellowstone National Park, the Garga hot spring in southern Russia and Lassen — home to Bumpass Hell.

    Over time, microbial mats can form into stromatolites, structures of microbes and minerals that have accumulated on top of one another; the layered appearance of a stromatolite reflects the passage of time, like a tree’s growth rings. Researchers found evidence of stromatolites in the Dresser Formation, a 3.5-billion–year-old rock feature in the Western Australia outback, along with evidence of hot spring mineral deposits, describing the findings in 2017 in Nature Communications. These findings, plus other signs of past microbes, led the team to suggest that some of the earliest life on Earth flourished in a hot spring environment.

    David Deamer, a biophysicist at UC Santa Cruz, has spent four and a half decades exploring how life on our planet may have begun. He started out studying lipids, oily molecules that make up the membranes surrounding cells. Deamer, a big proponent of hot springs as the source of life’s start, has shown that conditions at terrestrial hot springs can produce bubblelike vesicles, with an outer layer made up of lipids. Such structures may have been the ancestral precursors of modern-day cells (SN: 7/3/10, p. 22).

    Bruce Damer, an astrobiologist at UC Santa Cruz who brings a computer science approach to questions about the origins of life, worked with Deamer to test whether conditions at hot springs could drive condensation reactions, which join two molecules into one larger composite.

    When water splashes out of a hot spring and evaporates, molecules that were in the liquid could undergo condensation reactions and link up. A subsequent splash would add more molecules that could undergo additional condensation reactions as liquid dries again. Repeated rounds of wetting and drying could produce chains of molecules.

    In 2018, Damer set up shop at an active geothermal area in New Zealand, named along the usual theme — Hells Gate — to test that hypothesis. He prepared vials with ingredients needed to assemble strands of RNA, a nucleic acid that acts as a messenger during protein synthesis and may have catalyzed chemical reactions involved in the origins of life on early Earth (SN: 4/10/04, p. 232). The concoction included two of the four RNA building blocks — the nucleotides that link together to form RNA chains.

    2
    In February, astrobiologists Bruce Damer and Luke Steller (shown) performed wet-dry cycling experiments in acidic hot spring pools at Hells Gate in New Zealand. Credit: B. Damer.

    Damer stood the open vials in a metal block, roughly the size of two CD cases stacked together, and set the contraption into a near-boiling hydrothermal pool. To simulate the sometimes-wet, sometimes-dry burbling of the primordial Earth, Damer squirted acidic hot spring water into the vials, let them dry out and then repeated the wet-dry cycle several more times. When he brought the vials back to the lab, he found that they contained RNA-like strands that were 100 to 200 nucleotides long.

    These results, reported in December 2019 in Astrobiology, indicate that complex molecules can form at hot springs, supporting the hypothesis that life on Earth may have developed in such an environment. In 2020, Damer returned to Hells Gate with Deamer and colleagues to confirm Damer’s results and do more wet-dry cycling studies.

    Nicholas Hud, a chemist at Georgia Tech in Atlanta, studies the origins of life from a slightly different perspective: He explores how DNA and RNA nucleotides originated. He agrees that molecules are more likely to link together by condensation reactions on land, where wet-dry cycles can occur, than in the ocean. These reactions produce water; the formation of such a chemical bond isn’t energetically favorable when there’s already a lot of water around. “The best place to form that is in a hot, dry place,” Hud says. “The worst place to form it is in a wet, hot place.”

    3
    Bruce Damer has visited Hells Gate in New Zealand twice to test whether the conditions are right for linking nucleotides into strands of RNA. Credit: Joshua Hawley/iStock/Getty Images Plus.

    Underwater visions

    Yet, wet, hot environs are just the place for life to originate, other evidence suggests. At hydrothermal vents on the deep, dark ocean floor, heated water spews into seawater that’s just a few degrees Celsius above freezing (SN: 7/23/16, p. 8).

    In 2017, researchers found fossils in 3.77-billion-year-old rocks from Quebec that originated from the ancient ocean floor and had signs of hydrothermal activity (SN: 4/1/17, p. 6). The researchers claim that the distinct structures resemble those of microbes, suggesting that deep-sea environments may have supported some of the earliest life on Earth.

    These environments can be extreme: Some vents belch dark plumes of water as hot as 400° C. However, if vents played a role in nurturing early forms of life, it likely happened at milder vents. For example, Lost City is a hydrothermal area in the middle of the Atlantic Ocean where the fluid streaming from vents ranges in temperature from 40° to 90° C. The region is named for dramatic limestone chimneys that rise as much as 60 meters above the seafloor.

    4
    The chemistry of vents like the limestone chimneys found at the Atlantic Ocean’s Lost City supports microbial life. Credit: Courtesy of Susan Lang/Univ. of S. Carolina, NSF, ROV Jason/2018 © Woods Hole Oceanographic Institution.

    These spires are home to microbes that feed off the products of a chemical reaction known as serpentinization. “Hydrothermal vents are interesting because they are at the interface of water and rock,” says astrophysicist Laurie Barge of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

    A chemical reaction between water and rock at sites like Lost City makes the water coming out of vents more alkaline than the water in the ocean, which has a higher concentration of positively charged hydrogen ions. The resulting gradient from alkaline to more acidic water is like the difference between the positive and negative ends of a battery and can serve as an energy source for chemical activity.

    To study the conditions at underwater vents, Barge creates simulated environments in the lab that, she says, “can mimic what you see in the natural world.” To represent an ocean on early Earth, she fills an inverted glass bottle with an acidic mixture containing iron but no oxygen. One end of a plastic tube pokes through the narrow end of the bottle, connected to a steady supply of a basic, or alkaline, solution just like a vent.

    5
    NASA’s Laurie Barge simulates an alkaline hydrothermal vent in an acidic ocean to explore the chemistry of ancient oceans. The conditions produce chimney structures like the one above. Credit: NASA JPL-Caltech.

    When Barge and colleagues injected an alkaline vent solution containing RNA nucleotides into an ocean-simulating bottle, individual RNA nucleotides linked up into short chains. These strands were only three or four nucleotides long, but the results suggest that the conditions at deep-sea vents could have supported reactions that led to the emergence of life on Earth, the researchers proposed in 2015 in Astrobiology.

    Problems with both

    To Deamer, there are big barriers to putting life’s pieces together near underwater vents: The vastness of the ocean would dilute molecules so they wouldn’t be concentrated enough to drive chemical reactions. Also, there are “no wet-dry cycles underwater.” In his view, repeated evaporation is needed to pull together enough molecules to bump into each other and react to form longer chains. Plus, unlike a hot spring’s freshwater, salty ocean water inhibits the formation of membranes and reactions that link together molecules, he says.

    However, Deamer’s hot springs theory has its critics as well. DNA and RNA strands are composed of alternating phosphate and sugar molecules, but sugars “are profoundly unstable in hot spring environments,” says David Des Marais, an astrobiologist at NASA’s Ames Research Center.

    And it may be too soon to rule out wet-dry cycles underwater. “You can have a little bit of water get stuck in a pore,” says Bill Brazelton, a marine microbiologist at the University of Utah in Salt Lake City. And then, because the serpentinization reaction at a vent uses up water in making other molecules, “you can have these cycles of dehydration inside a rock underneath the ocean.”

    It may be impossible to nail down how life truly began on Earth: Most geologic records of what actually happened during Earth’s earliest days have long disappeared. There are numerous alternative hypotheses for where life began, beyond terrestrial hot springs and deep-sea vents. Recent research, for example, suggests that asteroid impacts could have sent superheated seawater into the crust to produce hydrothermal systems resembling hot springs (SN: 7/4/20, p. 10).

    “I think we have to admit that there might be more than one little torturous path that might have been traversed in order for life to begin,” Des Marais says.

    6
    The Bláhver hot spring in Iceland is one of many locations that Bruce Damer and David Deamer argue are the kind of environment where life may have formed on early Earth. Credit: imageBROKER/Alamy Stock Photo.

    Life beyond Earth

    Researchers are using what they’ve learned about how and where life may have originated on Earth to guide the search for biological signatures beyond our planet. There are several promising locales in our solar system.

    “One of the things that NASA is really interested in knowing is whether or not there could be life in the subsurface oceans of the icy moons, like Europa and Enceladus,” says Batalha, of UC Santa Cruz. Scientists have evidence that the two moons, one orbiting Jupiter and the other, Saturn, have oceans of salty, liquid water beneath their icy shells (SN Online: 6/14/19).

    These moons are intriguing because, along with liquid water, both have plumes of water erupting from their surfaces (SN: 6/9/18, p. 11), suggesting ongoing hydrothermal activity. NASA’s Cassini space probe even identified compounds containing carbon, nitrogen and oxygen within Enceladus’ plumes, some of the ingredients of amino acids, the building blocks of proteins. Europa and Enceladus fascinate astronomers because activity on their ocean floors may resemble the hydrothermal vents found on our own planet and may provide the chemical conditions to support life (SN: 4/18/15, p. 10).

    7
    Plumes of water vapor, plus compounds containing carbon, nitrogen and oxygen, spew from the frozen surface of Enceladus, a moon of Saturn, as captured by NASA’s Cassini spacecraft. Hydrogen in the plumes is evidence of hydrothermal activity in the ocean beneath the ice, similar to deep-sea vents on Earth. Credit: JPL-Caltech/NASA, Space Science Institute, Planetary Science Institute.

    Icy moons may also promote condensation reactions. “Even if you were on an icy moon, you might have … freezing and thawing of ice,” Barge says. “So, I think it’s important to say, if wet-dry cycling is important, then we should look for any environment in the solar system that might be able to promote oscillating conditions of dehydration.”

    But to find signs of past life, Damer and Deamer believe Mars is a more promising place to look. Mineral deposits indicate the presence of hot springs and hydrothermal activity in the planet’s past, which would have sustained the wetting and drying cycles that the two researchers see as crucial for condensation reactions to get life going.

    Missions to the Red Planet are already under way. NASA’s Perseverance rover will be searching for signs of ancient life, such as telltale minerals in rock samples, at Mars’ Jezero crater when the mission lands in February 2021 (SN: 7/4/20 & 7/18/20, p. 30). Though at least 54.6 million kilometers separate them, Mars and Bumpass Hell may not be so different.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 8:03 am on September 30, 2020 Permalink | Reply
    Tags: "Venus might be habitable today if not for Jupiter", Astrobiology, , , , , ,   

    From UC Riverside: “Venus might be habitable today, if not for Jupiter” 

    UC Riverside bloc

    From UC Riverside

    September 30th, 2020

    Jules L Bernstein
    Senior Public Information Officer
    jules.bernstein@ucr.edu
    (951) 827-4580

    Jupiter NASA ESA and A Simon GSFC.

    Hot as hell, but long ago Venus might have hosted abundant life. Credit: NASA/ROGER RESSMEYER/CORBIS/VCG.

    Study shows destabilizing effect of the giant gas planet.

    Venus might not be a sweltering, waterless hellscape today, if Jupiter hadn’t altered its orbit around the sun, according to new UC Riverside research.

    1
    Animation depicts eccentricities of the inner planet orbits, and illustrates how circular the orbit of Venus is. Credit: ChongChong He.

    Jupiter has a mass that is two-and-a-half times that of all other planets in our solar system — combined. Because it is comparatively gigantic, it has the ability to disturb other planets’ orbits.

    Early in Jupiter’s formation as a planet, it moved closer to and then away from the sun due to interactions with the disc from which planets form as well as the other giant planets. This movement in turn affected Venus.

    Observations of other planetary systems have shown that similar giant planet migrations soon after formation may be a relatively common occurrence. These are among the findings of a new study published in the Planetary Science Journal.

    Scientists consider planets lacking liquid water to be incapable of hosting life as we know it. Though Venus may have lost some water early on for other reasons, and may have continued to do so anyway, UCR astrobiologist Stephen Kane said that Jupiter’s movement likely triggered Venus onto a path toward its current, inhospitable state.

    “One of the interesting things about the Venus of today is that its orbit is almost perfectly circular,” said Kane, who led the study. “With this project, I wanted to explore whether the orbit has always been circular and if not, what are the implications of that?”

    To answer these questions, Kane created a model that simulated the solar system, calculating the location of all the planets at any one time and how they pull one another in different directions.

    Scientists measure how noncircular a planet’s orbit is between 0, which is completely circular, and 1, which is not circular at all. The number between 0 and 1 is called the eccentricity of the orbit. An orbit with an eccentricity of 1 would not even complete an orbit around a star; it would simply launch into space, Kane said.

    Currently, the orbit of Venus is measured at 0.006, which is the most circular of any planet in our solar system. However, Kane’s model shows that when Jupiter was likely closer to the sun about a billion years ago, Venus likely had an eccentricity of 0.3, and there is a much higher probability that it was habitable then.

    “As Jupiter migrated, Venus would have gone through dramatic changes in climate, heating up then cooling off and increasingly losing its water into the atmosphere,” Kane said.

    Recently, scientists generated much excitement by discovering a gas in the clouds above Venus that may indicate the presence of life. The gas, phosphine, is typically produced by microbes, and Kane says it is possible that the gas represents “the last surviving species on a planet that went through a dramatic change in its environment.”

    For that to be the case, however, Kane notes the microbes would have had to sustain their presence in the sulfuric acid clouds above Venus for roughly a billion years since Venus last had surface liquid water — a difficult to imagine though not impossible scenario.

    “There are probably a lot of other processes that could produce the gas that haven’t yet been explored,” Kane said.

    Ultimately, Kane says it is important to understand what happened to Venus, a planet that was once likely habitable and now has surface temperatures of up to 800 degrees Fahrenheit.

    “I focus on the differences between Venus and Earth, and what went wrong for Venus, so we can gain insight into how the Earth is habitable, and what we can do to shepherd this planet as best we can,” Kane said.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 3:16 pm on September 29, 2020 Permalink | Reply
    Tags: "Seed funding grants support plans for innovative research centers", , , Astrobiology, Cyber-Physical Systems for Intelligent Transportation, Energy-efficient Magnetoelectronics, Resilience to Climate Change in Crops with Artificial Intelligence, Splicing Therapeutics,   

    From UC Santa Cruz: “Seed funding grants support plans for innovative research centers” 

    From UC Santa Cruz

    September 28, 2020
    Tim Stephens
    stephens@ucsc.edu

    1

    The UCSC Office of Research has awarded seed funding to six campus research groups to support their efforts to develop innovative new research centers.

    The Seed Funding for Center Scale Research Initiatives program supports collaborative, multidisciplinary proposals and aims to bring together faculty with diverse backgrounds, areas of inquiry, and expertise.

    “Our goal with this program is to make strategic investments in collaborative and multidisciplinary projects that will lead to innovative, inventive, and serendipitous discoveries and findings with big impacts and significant long-term funding,” said Scott Brandt, vice chancellor for research. “Each of these projects meets these criteria and we are very excited to see what they will produce going forward.”

    The first cohort of awards includes the following groups:

    An Interdisciplinary Research Network for Astrobiology at UCSC,” led by Natalie Batalha, professor of astronomy and astrophysics, explores new models of planetary development and how it could lead to the conditions for life, and furthers our understanding of the prevalence of life in the universe.
    Developing a Collaborative, Interdisciplinary Center Research Proposal for Energy-efficient Magnetoelectronics,” led by David Lederman, professor of physics, will design 2-dimensional material layered stacks to precisely control performance properties such as magnetism and superconductivity at the quantum scale for future microelectronics.
    The Applied Artificial Intelligence Initiative,” led by J. Xavier Prochaska, professor of astronomy and astrophysics, will continue to build bridges across disciplines and between industry, academia, and under-represented minorities to develop UCSC as a leader in the growing field of artificial intelligence.
    Building Resilience to Climate Change in Crops with Artificial Intelligence and AgTech Devices,” led by Marco Rolandi, professor of electrical and computer engineering, will use bioelectronic devices paired with AI algorithms that can regulate specific plant hormones to increase agricultural yields and crop resilience.
    Computation-Aware Algorithmic Design for Cyber-Physical Systems for Intelligent Transportation,” led by Ricardo Sanfelice, professor of electrical and computer engineering, will build a framework for merging feedback control algorithms with computing system designs to reduce operational risks and optimize performance for intelligent transportation systems and other cyber-physical systems.
    UCSC Center for Open Access Splicing Therapeutics (COAST),” led by Michael Stone, professor of chemistry and biochemistry, will pursue meaningful precision therapies for patients with rare diseases. The COAST team will leverage their ribonucleic acid (RNA) expertise to intervene with small populations where the medical industry cannot make cost effective treatments economically viable.

    Each group will use their seed funding over the next year to pursue center-scale research proposals. The awards of $60,000 to $75,000 provide support for grant planning, capacity building, research development activities, and acquisition of key data.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Observatories Lick Automated Planet Finder, fully robotic 2.4-meter optical telescope at Lick Observatory, situated on the summit of Mount Hamilton, east of San Jose, California, USA.

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft).

    UC Santa Cruz campus.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory’s 36-inch Great Great Refractor telescope housed in the South (large) Dome of main building.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: