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  • richardmitnick 12:22 pm on January 5, 2019 Permalink | Reply
    Tags: , , , ‘Following the Water’, , , , , Fingerprinting Life, , , , , The habitable zone serves as a target selection tool, Trappist-1 star and planet system, , UCO Lick Observatory Mt Hamilton in San Jose California, UCR’s Alternative Earths Astrobiology Center   

    From UC Riverside: “Are We Alone?” 

    UC Riverside bloc

    From UC Riverside

    May 24, 2018
    Sarah Nightingale

    1
    Illustration by The Brave Union

    Forty years ago, the Voyager 2 spacecraft launched from Florida’s Cape Canaveral. Over the next decade, it swept across the solar system, sending back images of Jupiter’s volcanoes, Saturn’s rings, and for the first time, the icy atmospheres of Uranus and Neptune.

    NASA/Voyager 2

    2
    UCR’s Tim Lyons, left, and Stephen Kane are some of the only researchers in the world using Earth’s history as a guide to finding life in outer space. (Photo by Kurt Miller)

    The mission was more than enough to encourage Stephen Kane, a teenager growing up in Australia, to study planetary science in college. By the time he’d graduated, scientists had detected the first planet outside our solar system, known as an exoplanet, inspiring him to join the hunt and look for more.

    Over the past two decades, Kane, now an associate professor of planetary astrophysics at UC Riverside, has discovered hundreds of alien planets. At first, he focused on identifying giant Jupiter-like planets, which he describes as “low-hanging fruit” due to their large sizes. But in 2011, the Kepler Space Telescope identified the first rocky planet — Kepler 10b. Unlike gas giants such as Jupiter, rocky planets could potentially harbor life.

    NASA/Kepler Telescope

    With the discovery of more Earth-sized planets on the horizon, Kane realized that astrophysicists would struggle to understand the data they were receiving about terrestrial planets and their atmospheres.

    “During the course of the ongoing Kepler mission, I sought out planetary and Earth scientists because they’ve spent hundreds of years studying the solar system and how the Earth’s atmosphere has been shaped by biological and geophysical processes, so they have a lot to bring to the table,” Kane said.

    In 2017, Kane formalized that collaboration by joining an interdisciplinary research group led by Tim Lyons, a distinguished professor of biogeochemistry in the Department of Earth Sciences and director of UCR’s Alternative Earths Astrobiology Center. Backed by roughly $7.5 million from NASA, the center, one of only a handful like it in the world, brings together geochemists, biologists, planetary scientists, and astrophysicists from UCR and partner institutions to search for life on distant worlds using a template defined by the only known planet with life: Earth.

    3
    Astrobiology researchers study areas on Earth that hold evidence of ancient life, such as these stromatolites at the Hamelin Pool Marine Nature Reserve in Shark Bay, Australia. The rocky, dome-shaped structures formed in shallow water through the trapping of sedimentary grains by communities of microorganisms. (Photo by Mark Boyle)

    Fingerprinting Life

    Since its formation more than 4.5 billion years ago, Earth has undergone immense periods of geological and biological change.

    When the first life appeared — in the form of simple microbes — the sun was fainter, there were no continents, and there was no oxygen in the atmosphere. A new kind of life emerged around 2.7 billion years ago: photosynthetic bacteria that use the sun’s energy to convert carbon dioxide and water into food and oxygen gas. Multicellular life evolved from those bacteria, followed by more familiar lifeforms: fish about 530 million years ago, land plants 470 million years ago, and mammals 200 million years ago.

    “There are periods in the Earth’s past that are as different from one another as Earth is from an exoplanet,” Lyons said. “That is the concept of alternative Earths. You can slice the Earth’s history into chapters, pages, and even paragraphs, and there has been life evolving, thriving, surviving, and dying with each step. If we know what kind of atmospheres were present during the early stages of life on Earth, and their relationships to the evolving continents and oceans, we can look for similar signposts in our search for life on exoplanets.”

    While it might seem impossible to characterize ancient oceans and atmospheres, scientists can glean hints by studying rocks formed billions of years ago.

    “The chemical compositions of rocks are determined by the chemistry of the oceans and their life, and many of the gases in the atmosphere, through exchange with the oceans, are controlled by the same processes,” Lyons said. “These atmospheric fingerprints of life in the underlying oceans, or biosignatures, can be used as markers of life on other planets light years away.”

    The search for alien biosignatures typically centers on the gases produced by living creatures on Earth because they’re the only examples scientists have to work with. But Earth’s many chapters of inhabitation reveal the great number of possible gas combinations. Oxygen gas, ozone, and methane in a planet’s biosignature could all indicate the presence of life — and seeing them together could present an even stronger argument.

    The center’s search for life is different from the hunt for intelligent life. While those researchers probe for signs of alien civilizations, such as radio waves or powerful lasers, Lyons’ team is essentially looking for the byproducts of simple lifeforms.

    “As we’re exploring exoplanets, what we’re really trying to do is characterize their atmospheres,” he said. “If we see certain profiles of gases, then we may be detecting microbial waste products that are accumulating in the atmosphere.”

    The UCR team must also account for processes that produce the same gases without contributions from life, a phenomenon researchers call false positives. For example, a planetary atmosphere with abundant oxygen would be a promising biosignature, but that evidence could be misleading without fully addressing where it came from. Similarly, methane is a key biosignature, but there are many nonbiological ways to produce this gas on Earth. These distinctions require careful considerations of many factors, including seasonal patterns, tectonic activity, the type of planet and its star, among other data.

    False negatives are another concern, Lyons said. In previous research on ancient organic-rich rocks collected in Western Australia and South Africa, his group showed that about two billion years passed between the moment organisms first started producing oxygen on Earth and when it accumulated at levels high enough to be detectable in the atmosphere. In that scenario, a classic biosignature, oxygen, could be missed.

    “It’s also entirely possible that on some planets oxygen is produced through photosynthesis in pockets in the ocean and you’d never see it in the atmosphere,” Lyons said. “We have to be very clever to consider the many possibilities for biosignatures, and Earth’s past gives us many to choose from.”

    3
    Illustration by The Brave Union

    ‘Following the Water’

    With several hundred terrestrial planets confirmed and many more awaiting discovery, the search for life-bearing worlds is an almost overwhelming task.

    Astronomers are narrowing down their search by focusing on habitable zones — the orbital region around stars where it’s neither too hot nor too cold for liquid water to exist on the surface.

    “We know that liquid water is essential for life as we know it, and so we’re beginning our search by looking for planets that are capable of having similar environments to Earth. We call this approach ‘following the water,’” Kane said.

    While the habitable zone serves as a target selection tool, Kane said a planet nestled in this region won’t necessarily show signs of life — or even liquid water. Venus, for example, occupies the inner edge of the Sun’s habitable zone, but its scorching surface temperature has boiled away any liquid water that once existed.

    “We are extremely fortunate to have Venus in our solar system because it reminds us that a planet can be exactly the same size as Earth and still have things go catastrophically wrong,” Kane said.

    Equally important, being in the habitable zone doesn’t mean a planet will boast other factors that make Earth ideal for life. In addition to liquid water, the perfect candidate would have an insulating atmosphere and a protective magnetic field. It would also offer the right chemical ingredients for life and ways of recycling those elements over and over when continents collide, mountains lift up and wear down, and nutrients are swept back to the seas by rivers.

    “People question why we focus so intently on Earth, but the answer is obvious. We only know what we know about life because of what the Earth has given us,” said Lyons, who has spent decades reconstructing the conditions during which life evolved.

    “If I asked you to design a planet with the perfect conditions for life, you would design something just like Earth because it has all of these essential features,” he added. “We are studying how these building blocks have been assembled in different ways during Earth’s history and asking which of them are essential for life, which can be taken away. From that vantage point, we ask how they could be assembled in very different ways on other planets and still sustain life.”

    Kane said a distant planetary system called TRAPPIST-1, which NASA scientists discovered in 2017, could provide clues about the ingredients that are necessary for life.

    A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. NASA

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

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


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

    Although miniature compared to our own solar system — TRAPPIST-1 would easily fit inside Mercury’s orbit around the sun — it boasts seven planets, three of which are in the habitable zone. However, the planets don’t have moons, and they may not even have atmospheres.

    “We are finding that compact planetary systems orbiting faint stars are much more common than larger systems, so it’s important that we study them and find out if they could have habitable environments,” Kane said.

    4
    An artist’s illustration of the possible surface of TRAPPIST-1f, one of the planets in the TRAPPIST-1 system.

    Remote Observations

    At about 40 light-years (235 trillion miles) from Earth, the TRAPPIST-1 system is relatively close, but we’re never going to go there.

    “The fascinating thing about astronomy as a science is that it’s all based on remote observations,” Kane said. “We are trying to squeeze every piece of information we can out of photons that we are receiving from a very distant object.”

    While scientists have studied the atmospheres of several dozen exoplanets, most are too distant to probe with current instruments. That situation is changing. In April, NASA launched its Transiting Exoplanet Survey Satellite, known as TESS, which will seek Earth-sized planets around more than 500,000 nearby stars.

    NASA/MIT TESS

    In May 2020, NASA plans to launch the James Webb Space Telescope, which will perform atmospheric studies of the rocky worlds discovered by TESS.

    NASA/ESA/CSA Webb Telescope annotated

    Like Kepler, TESS detects exoplanets using the transit method, which measures the minute dimming of a star as an orbiting planet passes between it and the Earth.

    Planet transit. NASA/Ames

    Because light also passes through the atmosphere of planets, scientists will use the Webb telescope to identify the blanket of gases surrounding them through a technique called spectroscopy.

    Kane and Lyons are working with NASA to design missions that will directly image exoplanets in ways that will ensure that interdisciplinary teams such as theirs can properly interpret a wide variety of planetary processes.

    “As we design future missions, we must make sure they are equipped with the right instruments to detect biosignatures and geological processes, such as active volcanoes,” Kane said.

    UCR’s astrobiology team is one of only a few groups in the world studying ancient Earth to create a catalog of biosignatures that will inform mission design in NASA’s search for life on distant worlds. With quintillions — think the number of gallons of water in all of our oceans — of potentially habitable planets in the universe, Lyons said he is optimistic that we’ll find signs of life in the future.

    “Just like the Voyager missions were important because of what they taught us about our solar system — from the discovery of Jupiter’s rings to the first close-up glimpses of Uranus and Neptune — the TESS and James Webb missions, and more importantly the next generation of telescopes planned for the coming decades, are very likely to change our understanding of distant space,” Lyons said. And perhaps nestled in those discoveries will be an answer to the most fundamental of all questions, ‘are we alone?’

    Alternative Earths Astrobiology Center

    Founded in 2015

    One of 12 research teams funded by the NASA Astrobiology Institute, and one of only two using Earth’s history to guide exoplanet exploration

    Awarded $7.5 million over five years to cultivate a “search engine” for life on planets orbiting distant stars using Earth’s evolution over billions of years as a template

    Builds on existing UCR strengths in biogeochemistry, Earth history, and astrophysics

    Unites 66 researchers and staff at 11 institutions around the world, including primary partners led by former UCR graduate students now on the faculty at Yale and Georgia Tech

    4
    A NASA illustration of TESS monitoring stars outside our solar system.

    Through the Looking Glass

    In April, the Transiting Exoplanet Survey Satellite (TESS) Mission launched with the goal of discovering new Earths and super-Earths around nearby stars. As a guest investigator on the TESS Mission, Stephen Kane will use University of California telescopes, including those at the Lick Observatory in Mt. Hamilton to help determine whether candidate exoplanets identified by TESS are actually planets.

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

    UCSC Lick Automated Planet Finder telescope, Mount Hamilton, CA, 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 Shelley Wright at the 1-meter Nickel Telescope NIROSETI


    NIROSETI team from left to right Rem Stone UCO Lick Observatory Dan Werthimer UC Berkeley Jérôme Maire U Toronto, Shelley Wright UCSD Patrick Dorval U Toronto Richard Treffers Richard Treffers Starman Systems. (Image by Laurie Hatch)

    By studying the planet mass data obtained from the ground-based telescopes and planet diameter readings from spacecraft observations, Kane will also help determine the overall composition of the newly identified planets.

    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 10:21 am on November 28, 2018 Permalink | Reply
    Tags: , , , , The team found that all seven of the Trappist-1 worlds may have evolved like Venus, Trappist-1 star and planet system,   

    From University of Washington: “Study brings new climate models of small star TRAPPIST 1’s seven intriguing worlds” 

    U Washington

    From University of Washington

    November 20, 2018
    Peter Kelley

    Not all stars are like the sun, so not all planetary systems can be studied with the same expectations. New research from a University of Washington-led team of astronomers gives updated climate models for the seven planets around the star TRAPPIST-1.

    1
    The small, cool M dwarf star TRAPPIST-1 and its seven worlds. New research from the University of Washington speculates on possible climates of these worlds and how they may have evolved.NASA

    The work also could help astronomers more effectively study planets around stars unlike our sun, and better use the limited, expensive resources of the James Webb Space Telescope, now expected to launch in 2021.

    “We are modeling unfamiliar atmospheres, not just assuming that the things we see in the solar system will look the same way around another star,” said Andrew Lincowski, UW doctoral student and lead author of a paper published Nov. 1 in The Astrophysical Journal. “We conducted this research to show what these different types of atmospheres could look like.”

    The team found, briefly put, that due to an extremely hot, bright early stellar phase, all seven of the star’s worlds may have evolved like Venus, with any early oceans they may have had evaporating and leaving dense, uninhabitable atmospheres. However, one planet, TRAPPIST-1 e, could be an Earthlike ocean world worth further study, as previous research also has indicated.

    TRAPPIST-1, 39 light-years or about 235 trillion miles away, is about as small as a star can be and still be a star. A relatively cool “M dwarf” star — the most common type in the universe — it has about 9 percent the mass of the sun and about 12 percent its radius. TRAPPIST-1 has a radius only a little bigger than the planet Jupiter, though it is much greater in mass.

    All seven of TRAPPIST-1’s planets are about the size of Earth and three of them — planets labeled e, f and g — are believed to be in its habitable zone, that swath of space around a star where a rocky planet could have liquid water on its surface, thus giving life a chance. TRAPPIST-1 d rides the inner edge of the habitable zone, while farther out, TRAPPIST-1 h, orbits just past that zone’s outer edge.

    “This is a whole sequence of planets that can give us insight into the evolution of planets, in particular around a star that’s very different from ours, with different light coming off of it,” said Lincowski. “It’s just a gold mine.”

    Previous papers have modeled TRAPPIST-1 worlds, Lincowski said, but he and this research team “tried to do the most rigorous physical modeling that we could in terms of radiation and chemistry — trying to get the physics and chemistry as right as possible.”

    The team’s radiation and chemistry models create spectral, or wavelength, signatures for each possible atmospheric gas, enabling observers to better predict where to look for such gases in exoplanet atmospheres. Lincowski said when traces of gases are actually detected by the Webb telescope, or others, some day, “astronomers will use the observed bumps and wiggles in the spectra to infer which gases are present — and compare that to work like ours to say something about the planet’s composition, environment and perhaps its evolutionary history.”

    He said people are used to thinking about the habitability of a planet around stars similar to the sun. “But M dwarf stars are very different, so you really have to think about the chemical effects on the atmosphere(s) and how that chemistry affects the climate.”

    Combining terrestrial climate modeling with photochemistry models, the researchers simulated environmental states for each of TRAPPIST-1’s worlds.

    Their modeling indicates that:

    TRAPPIST-1 b, the closest to the star, is a blazing world too hot even for clouds of sulfuric acid, as on Venus, to form.
    Planets c and d receive slightly more energy from their star than Venus and Earth do from the sun and could be Venus-like, with a dense, uninhabitable atmosphere.
    TRAPPIST-1 e is the most likely of the seven to host liquid water on a temperate surface, and would be an excellent choice for further study with habitability in mind.
    The outer planets f, g and h could be Venus-like or could be frozen, depending on how much water formed on the planet during its evolution.

    Lincowski said that in actuality, any or all of TRAPPIST-1’s planets could be Venus-like, with any water or oceans long burned away. He explained that when water evaporates from a planet’s surface, ultraviolet light from the star breaks apart the water molecules, releasing hydrogen, which is the lightest element and can escape a planet’s gravity. This could leave behind a lot of oxygen, which could remain in the atmosphere and irreversibly remove water from the planet. Such a planet may have a thick oxygen atmosphere — but not one generated by life, and different from anything yet observed.

    “This may be possible if these planets had more water initially than Earth, Venus or Mars,” he said. “If planet TRAPPIST-1 e did not lose all of its water during this phase, today it could be a water world, completely covered by a global ocean. In this case, it could have a climate similar to Earth.”

    Lincowski said this research was done more with an eye on climate evolution than to judge the planets’ habitability. He plans future research focusing more directly on modeling water planets and their chances for life.

    “Before we knew of this planetary system, estimates for the detectability of atmospheres for Earth-sized planets were looking much more difficult,” said co-author Jacob Lustig-Yaeger, a UW astronomy doctoral student.

    The star being so small, he said, will make the signatures of gases (like carbon dioxide) in the planet’s atmospheres more pronounced in telescope data.

    “Our work informs the scientific community of what we might expect to see for the TRAPPIST-1 planets with the upcoming James Webb Space Telescope.”

    Lincowski’s other UW co-author is Victoria Meadows, professor of astronomy and director of the UW’s Astrobiology Program. Meadows is also principal investigator for the NASA Astrobiology Institute’s Virtual Planetary Laboratory, based at the UW. All of the authors were affiliates of that research laboratory.

    “The processes that shape the evolution of a terrestrial planet are critical to whether or not it can be habitable, as well as our ability to interpret possible signs of life,” Meadows said. “This paper suggests that we may soon be able to search for potentially detectable signs of these processes on alien worlds.”

    TRAPPIST-1, in the Aquarius constellation, is named after the ground-based Transiting Planets and Planetesimals Small Telescope, the facility that first found evidence of planets around it in 2015.

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


    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    Other co-authors are David Crisp of the Jet Propulsion Laboratory at the California Institute of Technology; Tyler Robinson of Northern Arizona University; Rodrigo Luger of the Flatiron Institute in New York City; and Giada Arney of the NASA/Goddard Space Flight Center in Greenbelt, Maryland. Robinson, Luger and Arney earned their doctoral degrees from the UW and were members of the UW Astrobiology Program.

    The team used storage and networking infrastructure provided by the Hyak supercomputer system at the UW, funded by the UW’s Student Technology Fee. The research was funded by the NASA Astrobiology Institute; Lincowski also received support from NASA under its Earth and Space Science Fellowship Program. The work benefited from researchers’ participation in the NASA Nexus for Exoplanet System Science (NExSS) research coordination network.

    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-washington-campus
    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
    So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
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