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  • richardmitnick 11:57 am on September 14, 2019 Permalink | Reply
    Tags: , , , , , COSMOS, , , ,   

    From from the University of Melbourne and Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) via COSMOS: “The hunt for a 12-billion-year-old signal” 

    From

    u-melbourne-bloc

    From University of Melbourne

    and

    arc-centers-of-excellence-bloc

    From ARC Centres of Excellence

    via

    10 September 2019
    Nick Carne

    1
    In this image the Epoch of Reionization, neutral hydrogen, in red, is gradually ionised by the first stars, shown in white.
    Paul Giel and Simon Mutch / UNIVERSITY OF MELBOURNE DARK-AGES REIONIZATION AND GALAXY OBSERVABLES FROM NUMERICAL SIMULATIONS (DRAGONS) PROGRAM

    Astronomers believe they are closing in on a signal that has been travelling across the Universe for 12 billion years.

    In a paper soon to be published in The Astrophysical Journal, an international team reports a 10-fold improvement on data gathered by the Murchison Widefield Array (MWA), a collection of 4096 dipole antennas set in the remote hinterland of Western Australia.

    SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    The MWA was built specifically to detect electromagnetic radiation emitted by neutral hydrogen – a gas that made up most of the infant Universe in the period when the soup of disconnected protons and neutrons spawned by the Big Bang started to cool down.

    Eventually those atoms began to clump together to form the very first stars, initiating the major phase in the evolution of the Universe known as the Epoch of Reionization, or EoR.

    2
    Epoch of Reionization. Caltech/NASA

    “Defining the evolution of the EoR is extremely important for our understanding of astrophysics and cosmology,” says research leader Nichole Barry from the University of Melbourne and Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D).

    “So far, though, no one has been able to observe it. These results take us a lot closer to that goal.”

    The neutral hydrogen that dominated space and time before and in the early period of the EoR radiated at a wavelength of approximately 21 centimetres.

    Stretched now to somewhere above two metres because of the expansion of the Universe, the signal persists – and detecting it remains the theoretical best way to probe conditions in the early days of the Cosmos.

    But that’s difficult to do, the researchers say, as the signal is old and weak and there are a lot of other galaxies in the way.

    That means the signals recorded by the MWA and other EoR-hunting devices, such as the Hydrogen Epoch of Reionisation Array (HERA) in South Africa and the Low Frequency Array (LOFAR) in The Netherlands, are extremely messy.

    UC Berkeley Hydrogen Epoch of Reionization Array (HERA), South Africa

    ASTRON LOFAR Radio Antenna Bank, Netherlands

    Using 21 hours of raw data, Barry and colleagues explored new techniques to refine analysis and exclude consistent sources of signal contamination, including ultra-faint interference generated by radio broadcasts on Earth.

    The result was a level of precision that significantly reduced the range in which the EoR may have begun, pulling in constraints by almost an order of magnitude.

    “We can’t really say that this paper gets us closer to precisely dating the start or finish of the EoR, but it does rule out some of the more extreme models,” says co-author Cathryn Trott, from Australia’s Curtin University.

    “That it happened very rapidly is now ruled out. That the conditions were very cold is now also ruled out.”

    The research was conducted by researchers from a number of institutions in Australia and New Zealand, in collaboration with Arizona State University, Brown University and MIT in the US, Kumamoto University in Japan, and Raman Research Institute in India.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The objectives for the ARC Centres of Excellence are to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
    develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
    offer Australian researchers opportunities to work on large-scale problems over long periods of time
    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

    u-melbourne-campus

    The University of Melbourne (informally Melbourne University) is an Australian public research university located in Melbourne, Victoria. Founded in 1853, it is Australia’s second oldest university and the oldest in Victoria. Times Higher Education ranks Melbourne as 33rd in the world, while the Academic Ranking of World Universities places Melbourne 44th in the world (both first in Australia).

    Melbourne’s main campus is located in Parkville, an inner suburb north of the Melbourne central business district, with several other campuses located across Victoria. Melbourne is a sandstone university and a member of the Group of Eight, Universitas 21 and the Association of Pacific Rim Universities. Since 1872 various residential colleges have become affiliated with the university. There are 12 colleges located on the main campus and in nearby suburbs offering academic, sporting and cultural programs alongside accommodation for Melbourne students and faculty.

    Melbourne comprises 11 separate academic units and is associated with numerous institutes and research centres, including the Walter and Eliza Hall Institute of Medical Research, Florey Institute of Neuroscience and Mental Health, the Melbourne Institute of Applied Economic and Social Research and the Grattan Institute. Amongst Melbourne’s 15 graduate schools the Melbourne Business School, the Melbourne Law School and the Melbourne Medical School are particularly well regarded.

    Four Australian prime ministers and five governors-general have graduated from Melbourne. Nine Nobel laureates have been students or faculty, the most of any Australian university.

     
  • richardmitnick 11:40 am on September 9, 2019 Permalink | Reply
    Tags: "Super corals can handle acid; heat; and suffocation", , COSMOS, , University of Technology Sidney   

    From University of Technology Sidney via Cosmos: “Super corals can handle acid, heat and suffocation” 

    1

    From University of Technology Sidney

    via

    Cosmos Magazine bloc

    COSMOS Magazine

    Emma F Camp
    David Suggett

    1
    Resilient corals are offering hope for bleached reefs. Emma Camp

    Climate change is rapidly changing the oceans, driving coral reefs around the world to breaking point. Widely publicised marine heatwaves aren’t the only threat corals are facing: the seas are increasingly acidic, have less oxygen in them, and are gradually warming as a whole.

    Each of these problems reduces coral growth and fitness, making it harder for reefs to recover from sudden events such as massive heatwaves.

    Our research, published in Marine Ecology Progress Series, investigates corals on the Great Barrier Reef that are surprisingly good at surviving in increasingly hostile waters. Finding out how these “super corals” can live in extreme environments may help us unlock the secret of coral resilience helping to save our iconic reefs.

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    Bleached coral in the Seychelles. Emma Camp, Author provided.

    Coral conservation under climate change

    The central cause of these problems is climate change, so the central solution is reducing carbon emissions. Unfortunately, this is not happening rapidly enough to help coral reefs, so scientists also need to explore more immediate [Nature Ecology & Evolution] conservation options.

    To that end, many researchers have been looking at coral that manages to grow in typically hostile conditions, such as around tide pools and intertidal reef zones, trying to unlock how they become so resilient.

    These extreme coral habitats are not only natural laboratories, they house a stockpile of extremely tolerant “super corals” [Global Change Biology].

    What exactly is a super coral?

    “Super coral” generally refers to species that can survive both extreme conditions and rapid changes in their environment. But “super” is not a very precise term!

    Our previous research quantified these traits so other ecologists can more easily use super coral in conservation. There are a few things that need to be established to determine whether a coral is “super”:

    What hazard can the coral survive? For example, can it deal with high temperature, or acidic water?

    How long did the hazard last? Was it a short heatwave, or a long-term stressor such as ocean warming?

    Did the coral survive because of a quality such as genetic adaption, or was it tucked away in a particularly safe spot?

    How much area does the coral cover? Is it a small pocket of resilience, or a whole reef?

    Is the coral trading off other important qualities to survive in hazardous conditions?

    Is the coral super enough to survive the changes coming down the line? Is it likely to cope with future climate change?

    If a coral ticks multiple boxes in this list, it’s a very robust species. Not only will it cope well in our changing oceans, we can also potentially distribute these super corals along vulnerable reefs [PNAS].

    4
    Some corals cope surprisingly well in different conditions. Emma Camp, Author provided.

    Mangroves are surprise reservoirs

    We discovered mangrove lagoons near coral reefs can often house corals living in very extreme conditions – specifically, warm, more acidic and low oxygen seawater.

    Previously we have reported corals living in extreme mangroves of the Seychelles, Indonesia, New Caledonia – and in our current study living on the Great Barrier Reef. We report diverse coral populations surviving in conditions more hostile than is predicted over the next 100 years of climate change [Frontiers in Marine Science].

    Importantly, while some of these sites only have isolated populations, other areas have actively building reef frameworks.

    Particularly significant were the two mangrove lagoons on the Great Barrier Reef. They housed 34 coral species, living in more acidic water with very little oxygen. Temperatures varied widely, over 7℃ in the period we studied – and included periods of very high temperatures that are known to cause stress in other corals.

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    Mangrove lagoons can contain coral that survives in extremely hostile environments, while nearby coral reefs bleach in marine heatwaves. Emma Camp, Author provided.

    While coral cover was often low and the rate at which they build their skeleton was reduced, there were established coral colonies capable of surviving in these conditions.

    The success of these corals reflect their ability to adapt to daily or weekly conditions, and also their flexible relationship with various symbiotic micro-algae that provide the coral with essential resources.

    While we are still in the early phases of understanding exactly how these corals can aid conservation, extreme mangrove coral populations hold a reservoir of stress-hardened corals. Notably the geographic size of these mangrove locations are small, but they have a disproportionately high conservation value for reef systems.

    However, identification of these pockets of extremely tolerant corals also challenge our understanding of coral resilience, and of the rate and extent with which coral species can resist stress.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    UTS is a public university of technology defined by our support for the economic, social and cultural prosperity of our communities. We are measured by the success of our students, staff and partners and committed to research, innovation and the dissemination of knowledge of public value. We are, and always will be, an inclusive university.

    UTS has a culturally diverse campus life and vibrant international exchange study and research programs that prepare graduates for the workplaces of today and the future. Our campus is in the heart of Sydney’s creative and digital precinct and alongside Sydney’s central business district. Continuing a 10-year period of major development, the ongoing transformation of the UTS campus will ensure we continue to maintain and develop a purpose- and sustainably-built campus to support innovation in education and research.

    Our UTS 2027 strategy outlines our vision to be “a leading public university of technology recognised for our global impact” . Our purpose is to advance knowledge and learning through research-inspired teaching, research with impact and partnerships with industry, the professions and community. UTS is part of the Australian Technology Network of universities: a group of prominent universities committed to working with industry and government to deliver practical and professional courses.

    With a total enrolment of over 44,000 students, UTS is one of the largest universities in Australia.

     
  • richardmitnick 8:51 am on August 22, 2019 Permalink | Reply
    Tags: , COSMOS, , ,   

    Woods Hole Oceanographic Institute via COSMOS: ” Geology creates chemical energy” 

    From Woods Hole Oceanographic Institute

    22 August 2019

    Origin of a massive methane reservoir discovered.

    1
    The manipulator arm of the remotely operated vehicle Jason samples a stream of fluid from a hydrothermal vent.
    Chris German/WHOI/NSF, NASA/ROV Jason 2012 / Woods Hole Oceanographic Institution

    Scientists know methane is released from deep-sea vents, but its source has long been a mystery.

    Now a team from Woods Hole Oceanographic Institution, US, may have the answer. Analysis of 160 rock samples from across the world’s oceans provides evidence, they say, of the formation and abundance of abiotic methane – methane formed by chemical reactions that don’t involve organic matter.

    Nearly every sample contained an assemblage of minerals and gases that form when seawater, moving through the deep oceanic crust, is trapped in magma-hot olivine, a rock-forming mineral, the researchers write in a paper published in Proceedings of the National Academy of Science.
    .

    As the mineral cools, the water trapped inside undergoes a chemical reaction, a process called serpentinisation, which forms hydrogen and methane.

    “Here’s a source of chemical energy that’s being created by geology,” says co-author Jeffrey Seewald.

    On Earth, deep-sea methane might have played a critical role for the evolution of primitive organisms living at hydrothermal vents on the seafloor, Seewald adds. And elsewhere in the solar system, methane produced through the same process could provide an energy source for basic life forms.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Woods Hole Oceanographic Institute

    Vision & Mission

    The ocean is a defining feature of our planet and crucial to life on Earth, yet it remains one of the planet’s last unexplored frontiers. For this reason, WHOI scientists and engineers are committed to understanding all facets of the ocean as well as its complex connections with Earth’s atmosphere, land, ice, seafloor, and life—including humanity. This is essential not only to advance knowledge about our planet, but also to ensure society’s long-term welfare and to help guide human stewardship of the environment. WHOI researchers are also dedicated to training future generations of ocean science leaders, to providing unbiased information that informs public policy and decision-making, and to expanding public awareness about the importance of the global ocean and its resources.
    Mission Statement

    The Woods Hole Oceanographic Institution is dedicated to advancing knowledge of the ocean and its connection with the Earth system through a sustained commitment to excellence in science, engineering, and education, and to the application of this knowledge to problems facing society.

     
  • richardmitnick 9:23 am on August 16, 2019 Permalink | Reply
    Tags: "Superdeep diamonds have a story to tell", , “If we have a lot of helium-4 it means it must have had quite a bit of time to form. If we find a lot of helium-3 this must be because it’s ancient.”, COSMOS, Focusing on helium gas trapped in tiny bubbles of fluid in 23 of these diamonds., , Helium comes in two forms: helium-3 and helium-4.   

    From COSMOS Magazine: “Superdeep diamonds have a story to tell” 

    Cosmos Magazine bloc

    16 August 2019
    Richard A Lovett

    1
    Diamonds from the Juina area of Brazil. Most are superdeep diamonds. Credit Graham Pearson

    Tiny imperfections in Brazilian diamonds have revealed a pocket of the Earth’s primordial past, deep in its interior.

    In fact, scientists say, these rocks appear to have survived largely undisturbed for 4.5 billion years, making them older than the Moon or anything on the Earth’s surface.

    Diamonds form naturally only under high-pressure conditions existing deep beneath the Earth’s crust. That makes them messengers from the mantle, which then rise toward the surface via volcanic conduits, where miners ultimately find them.

    Most diamonds form at depths of 150 to 200 kilometres, says Suzette Timmerman, a Dutch geochemist who conducted her research at Australian National University. Diamonds from the Juina area of western Brazil are different, however.

    “The Juina area is special because more than 99% of the diamonds form between 410 and 660 kilometres in depth,” she says.

    That’s important, because diamonds are notoriously durable.

    “Diamonds are the hardest, most indestructible natural substance known,” she says, “so they form a perfect window into the deep Earth.”

    Timmerman’s study, published in the journal Science, focused on helium gas trapped in tiny bubbles of fluid in 23 of these diamonds.

    Helium comes in two forms: helium-3 and helium-4. The early Solar System had a mix of the two determined by the composition of the interstellar gas cloud from which it formed. But helium-4 continues to be formed as a byproduct of certain types of radioactive decay, particularly the decay of heavy elements such as uranium and thorium.

    “If we have a lot of helium-4, it means it must have had quite a bit of time to form,” Timmerman says. “If we find a lot of helium-3, this must be because it’s ancient.”

    It’s not quite that simple, of course, because geological processes when the Earth was young tended to move uranium and thorium (and their subsequent production of helium-4) out of the mantle into upper-level rocks.

    But when this is corrected for, Timmerman says, the helium isotope ratios in her diamonds prove that the helium trapped within them comes from regions very close in composition to the primordial matter from which the Earth initially formed – mantle rocks that, for whatever reason, never mixed with the rest of the mantle or with material descending from the crust.

    “In order to get the compositions we see today,” she says, “it mustn’t have interacted with the rest of the mantle at least since the core and mantle separated” – something that probably occurred in the aftermath of the giant impact that formed the Moon. “It’s definitely a part of the Earth that hasn’t been interacting with the crust, basically since the beginning of time.”

    How much of this primordial matter remains is unclear, she says, but one place it apparently does exist is beneath the diamond mines of Brazil. And, she notes, “with this work we are beginning to home in on what is probably the oldest remaining, comparatively undisturbed, material on Earth”.

    Other scientists are impressed. “This is an interesting result, with a lot of potential to ‘map out’ elevated helium-3/helium-4 domains in the Erath’s deep interior,” says Matthew Jackson, a geochemist at the University of California, Santa Barbara who was not part of the study team.

    It’s also intriguing because it comes only a year before the Japanese space agency hopes to return a sample of even more primordial material from asteroid 162173 Ryugu, and four years before NASA hopes to do the same for asteroid 101955 Bennu.

    See the full article here .


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  • richardmitnick 7:52 am on August 1, 2019 Permalink | Reply
    Tags: "When it comes to volcanoes Monte Carlo may save Naples", , COSMOS, , , Monte Carlo simulations,   

    From COSMOS Magazine: “When it comes to volcanoes, Monte Carlo may save Naples” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    01 August 2019
    Barry Keily

    Researchers combine stress and statistics to refine eruption risk.

    1
    Monte Nuovo is the vent of one of the smallest eruptions at Campi Flegrei, Italy. Credit Mauro Antonio Di Vito.

    Contrary to cartoon depictions, volcanoes rarely erupt more than once from the same hole. In some cases, explosive ejections of magma, ash and rocks can kick off a substantial distance away from previous hotspots.

    The ability to identify with any degree of precision likely eruption sites is a matter that has been the subject of intensive research for decades, but to date evidence has been substantially, and sometimes catastrophically, at odds with predictions.

    Now, however, a team led by Eleonora Rivalta from the GFZ German Research Centre for Geosciences, in Potsdam, Germany, has come up with a new and promising approach that marries physics and mathematics.

    Although the method has yet to be real-world tested, the researchers report that a retrospective comparison using eruptions that took place over centuries at Italy’s densely populated Campi Flegrei volcanic field, which includes the city of Naples, has shown encouraging results.

    The problem of predicting exact eruption spots is at its keenest in the case of calderas – volcanoes on which the summit has collapsed, leaving craters that can be as big as 100 kilometres in diameter.

    “Calderas have fed some of the most catastrophic eruptions on Earth and are extremely hazardous,” Rivalta and colleagues write in the journal Science Advances.

    “However, their eruptions are generally few and far apart; thus, hazard is often underestimated by the local population, which, at some calderas, approaches one million.”

    Predicting when and where eruptions could happen, the researchers add, is thus regarded as “extremely challenging”.

    The difficulty arises because it is impossible to test the assumptions on which current models rest.

    Hazard estimation proceeds from the not unreasonable idea that future eruptions are likely to occur in close proximity to the sites of past ones.

    However, this presumes that the distribution of past volcanic vents indicates areas of geologic weakness. Such a presumption, the researchers write, is not supported by the evidence.

    A second approach concedes an unknown mechanism determines the path which ascending magma takes but assumes there is a higher probability of a new vent opening near clusters of old ones than in somewhere unscarred.

    This method is valid, Rivalta and colleagues confirm, inasmuch as the probabilities are borne out by the history of eruptions on Campi Flegrei, but because these events don’t happen very often, the number of available data points is insufficient to produce predictions with a useful degree of precision.

    To overcome these issues, the researchers turned to the physics of magma flows, a field that has been comprehensively studied ever since Canadian geologist Reginal Aldworth Daly published the first research on it in the late nineteenth century.

    They combined this with a statistical approach known as the Monte Carlo method, wherein calculations of events are run thousands of times in order to encompass the possible influence of unpredictable variables.

    Monte Carlo simulations are widely used for risk analysis in fields as diverse as insurance, mining and finance.

    Rivalta and colleagues based the limits of their calculations on existing data describing the stresses present, and already measured, across Campi Flegrei. The results showed that previous assumptions regarding the importance of existing faults in influencing magma flow were incorrect.

    Faults certainly play a role, but it is less significant than assumed, and less direct – magma is likely to move at a tangent to them rather than mirror them.

    Instead, the results showed that it was possible to predict the direction of magma flows as long as the stresses involved and the exact location of the subterranean magma chamber were known – matters that the researchers quickly concede are often “very poorly constrained”.

    Nevertheless, they conclude, their method produces more accurate predictions – at least retrospectively – than existing ones.

    “We show that magma trajectories, and thus eruptive vent locations, are so sensitive to stress variations that the previous vent locations at a volcano can be used to constrain the stress field to a sufficient degree of accuracy to render reliable physics-based vent forecasts possible,” they write.

    See the full article here .


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  • richardmitnick 9:36 am on July 27, 2019 Permalink | Reply
    Tags: "Astronomers see the Sun’s future in a dying star", , , , , , COSMOS, The convulsion of T Ursae Minoris (T UMi)   

    From COSMOS Magazine: “Astronomers see the Sun’s future in a dying star” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    27 July 2019

    T UMi’s convulsion a rare dynamic event.

    1
    The Sun and T UMi are expected to end their days much like U Camelopardalis (pictured).
    European Space Agency/Hubble

    NASA/ESA Hubble Telescope

    Astronomers have witnessed a rare dynamic event they say reinforces predictions about the Sun’s ultimate demise.

    The convulsion of T Ursae Minoris (T UMi) – a star similar to the Sun but older and nearer the end of its life – was significant because “the signs of ageing could be directly observed in a star over human timescales,” says Meredith Joyce from the Australian National University.

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    Dr Meridith Joyce. Lannon Harley, ANU

    This supports the idea that the Sun will turn into a red giant and then into an expanding and glowing ring-shaped shell of gas in five billion years, leaving behind a small white dwarf as a remnant.

    “It will become much bigger as it approaches death – eating Venus, Mercury and possibly the Earth in the process – before shrinking to become a white dwarf,” says Joyce, who led the international study with László Molnár and László Kiss from the Hungarian Academy of Sciences.

    Their findings are reported in a paper in The Astrophysical Journal.

    T UMi was born about 1.2 billion years ago, with a mass roughly twice that of the Sun, in the Little Bear constellation more than 3000 light-years from Earth.

    The researchers found that over the past few million years, during its last stage of life before its ultimate transition to a white dwarf, it has been undergoing a series of pulses, whereby its size, brightness and temperature have fluctuated enormously.

    “Energy production in T UMi has become unstable. During this phase, nuclear fusion flares up deep inside, causing ‘hiccups’ that we call thermal pulses,” says Joyce.

    “These pulses cause drastic, rapid changes in the size and brightness of the star, which are detectable over centuries. The pulses of old stars like T UMi also enrich the entire universe with elements including carbon, nitrogen, tin and lead.”

    Joyce and colleagues believe the star is entering one of its last remaining pulses. They expect to see it expanding again “in our lifetimes”, before becoming a white dwarf within a few hundred thousand years.

    “Both amateur and professional astronomers will continue to observe the evolution of the star in the coming decades, which will provide a direct test of our predictions within the next 30 to 50 years,” she says.

    See the full article here .
    See also ANU article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 10:16 pm on July 22, 2019 Permalink | Reply
    Tags: "10 billion years ago the Milky Way ate a smaller galaxy dubbed Gaia-Enceladus", , , , , COSMOS, ,   

    From COSMOS Magazine: “10 billion years ago, the Milky Way ate a smaller galaxy dubbed Gaia-Enceladus” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    23 July 2019
    Barry Keily

    1
    Artist’s impression of the merger between the Gaia-Enceladus galaxy and the Milky Way. NASA/ESA/Hubble, CC BY-SA 3.0 IGO

    NASA/ESA Hubble Telescope

    The Milky Way achieved its present form about 10 billion years ago when it merged with a smaller, neighbouring galaxy, new observations and modelling show.

    Researchers led by astrophysicist Carme Gallar of the Universidad de La Laguna in Spain took advantage of measurements taken by the European Space Agency’s Gaia space observatory, which was launched in 2013 for the dedicated purpose of mapping the positions of stars with unprecedented accuracy.

    ESA/GAIA satellite

    They took the new data and subjected it to the two most commonly used techniques for estimating the age of stars – comparison with existing stellar models and what is known as colour-magnitude diagram fitting.

    The approach was applied to Gaia measurements for the galaxy’s two outer rings of stars – known as the blue and red haloes – and what astronomers call its thick central disc.

    The results showed that the stars in the haloes were all more ancient than those in the disc, with those in the former category all exceeding 10 billion years old.

    MIlky Way Galaxy NASA/JPL-Caltech /ESO R. Hurt

    The sharp age difference, the researchers say, confirms and, for the first time, accurately dates a titanic encounter between the progenitor of the Milky Way and a neighbouring, smaller galaxy, dubbed Gaia-Enceladus.

    The different colours of the two haloes are an indication of the iron content of their respective stars. Red stars contain more of it than blue ones. Colour also often indicates great age. Until now, thus, astronomers assumed that the Milky Way’s blue halo was younger than its red one.

    Gallar and colleagues used Gaia data to show that this is not the case. Their modelling reveals that the red and blue haloes contain stars of identical age, and that each region started and ceased star production at about the same time.

    The difference in iron content, the researchers say, is a function of a galaxy size – more massive galaxies contain larger amounts of metal than smaller ones. Thus, they write, the result “means that the stars in the red sequence of the halo, being more metal-rich, must have formed in a galaxy that was more massive than the one where the stars in the blue sequence were formed.”

    The blue halo, they say, represents the remnants of Gaia-Enceladus – a galaxy they estimate to have been around a quarter of the size of the proto Milky Way.

    The research is published in the journal Nature Astronomy.

    See the full article here .


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  • richardmitnick 9:53 am on July 21, 2019 Permalink | Reply
    Tags: , , , Cecilia Payne, , COSMOS, , Payne discovered that hydrogen and helium are the dominant elements of the stars -1925 Ph.D. thesis., ,   

    From COSMOS Magazine: Women in STEM- “This week in science history: The woman who found hydrogen in the stars is born” Cecilia Payne 

    Cosmos Magazine bloc

    From COSMOS Magazine

    THIS POST IS DEDICATED TO L.Z. OF RUTGERS PHYSICS AND HP, WHO BROUGHT CECILIA PAYNE TO MY ATTENTION. I HOPE HE SEES THIS. IF HE SEES IT, HE CAN ADVISE ME BY EMAIL.

    1
    Meet the Woman Who Discovered the Composition of the Stars, Cecilia Payne. Mental Floss, Caitlin Schneider August 26, 2015

    Cecilia Payne is today recognised as an equal to Newton and Einstein, but it wasn’t always so.

    10 May 2018
    Jeff Glorfeld

    2
    Cecilia Payne, photographed in 1951. Bettmann / Contributor / Getty Images

    Cecilia Payne, born on May 10, 1900, in Wendover, England, began her scientific career in 1919 with a scholarship to Cambridge University, where she studied physics. But in 1923 she received a fellowship to move to the United States and study astronomy at Harvard. Her 1925 thesis, Stellar Atmospheres, was described at the time by renowned Russian-American astronomer Otto Struve as “the most brilliant PhD thesis ever written in astronomy”.

    In the January, 2015, Richard Williams of the American Physical Society, wrote: “By calculating the abundance of chemical elements from stellar spectra, her work began a revolution in astrophysics.”

    In 1925 Payne received the first PhD in astronomy from Radcliffe, Harvard’s college for women, – because Harvard itself did not grant doctoral degrees to women.

    In the early 1930s she met Sergey Gaposchkin, a Russian astronomer who could not return to the Soviet Union because of his politics. Payne was able to find a position at Harvard for him. They married in 1934.

    Finally, in 1956, she achieved two Harvard firsts: she became its first female professor, and the first woman to become department chair.

    In a 2016 article about Payne for New York magazine, writer Dava Sobel reports that when she arrived at Harvard, Payne found the school had a collection of several hundred thousand glass photographs of the night sky, taken over a period of 40 years. Many of these images stretched starlight into strips, or spectra, marked by naturally occurring lines that revealed the constituent elements.

    As she painstakingly examined these plates, Payne reached her controversial – and groundbreaking – conclusion: that unlike on Earth, hydrogen and helium are the dominant elements of the stars.

    At the time, most scientists believed that because stars contained familiar elements such as silicon, aluminium and iron, similar to Earth’s make-up, they would be present in the same proportions, with only small amounts of hydrogen.

    Although the presence of hydrogen in stars had been known since the 1860s, when chemical analysis at a distance first became possible, no one expected the great abundance claimed by Payne.

    Richard Williams, writing for the American Physical Society in 2015, said: “The giants – Copernicus, Newton, and Einstein – each in his turn, brought a new view of the universe. Payne’s discovery of the cosmic abundance of the elements did no less.”

    However, at the time of her thesis publication the foremost authority on stellar composition, Henry Norris Russell, of Princeton University, convinced Payne that her conclusions had to be wrong, encouraging her write that her percentages of hydrogen and helium were “improbably high” and therefore “almost certainly not real”.

    But in brilliant vindication, Russell devoted the next four years to studying Payne’s findings, and in the issue of the Astrophysical Journal, he agreed with her and cited her 1925 study, concluding for the record that the great abundance of hydrogen “can hardly be doubted”.

    Cecilia Payne-Gaposchkin died on December 7, 1979.

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 1:12 pm on July 11, 2019 Permalink | Reply
    Tags: , Coral on the move to escape sea heat, COSMOS, , ,   

    From University of Washington and COSMOS: “Reefs on the move- Coral reefs shifting away from equator, new study finds” 

    U Washington

    From University of Washington

    AND

    Cosmos Magazine bloc

    From COSMOS Magazine

    July 9, 2019

    1
    Corals and kelp.Soyoka Muko/Nagasaki University

    Coral reefs are retreating from equatorial waters and establishing new reefs in more temperate regions, according to new research published July 4 in the journal Marine Ecology Progress Series. The researchers found that the number of young corals on tropical reefs has declined by 85% — and doubled on subtropical reefs — during the last four decades.

    “Climate change seems to be redistributing coral reefs, the same way it is shifting many other marine species,” said lead author Nichole Price, a senior research scientist at Bigelow Laboratory for Ocean Sciences in Maine. “The clarity in this trend is stunning, but we don’t yet know whether the new reefs can support the incredible diversity of tropical systems.”

    As climate change warms the ocean, subtropical environments are becoming more favorable for corals than the equatorial waters where they traditionally thrived. This is allowing drifting coral larvae to settle and grow in new regions. These subtropical reefs could provide refuge for other species challenged by climate change and new opportunities to protect these fledgling ecosystems.

    “This study is a great example of the importance of collaborating internationally to assess global trends associated with climate change and project future ecological interactions,” said co-author Jacqueline Padilla-Gamiño, an assistant professor at the University of Washington School of Aquatic and Fishery Sciences. “It also provides a nugget of hope for the resilience and survival of coral reefs.”

    The researchers believe that only certain types of coral are able to reach these new locations, based on how far the microscopic larvae can swim and drift on currents before they run out of their limited fat stores. The exact composition of most new reefs is currently unknown, due to the expense of collecting genetic and species diversity data.

    “We are seeing ecosystems transition to new blends of species that have never coexisted, and it’s not yet clear how long it takes for these systems to reach equilibrium,” said co-author Satoshi Mitarai, an associate professor at Okinawa Institute of Science and Technology Graduate University who earned his doctorate at the UW. “The lines are really starting to blur about what a native species is, and when ecosystems are functioning or falling apart.”

    2
    The study site on Palmyra Atoll, one of the Northern Line Islands that lies between Hawaii and American Samoa.
    Nichole Price/Bigelow Laboratory for Ocean Sciences

    This experiment in the Palmyra Atoll National Wildlife Refuge in the Pacific is allowing researchers to enumerate the number of baby corals settling on a reef.

    Recent studies show that corals are establishing new reefs in temperate regions as they retreat from increasingly warmer waters at the equator.

    Writing in the journal Marine Ecology Progress Series [above], researchers from 17 institutions in six countries report that the number of young corals has declined by 85% on tropical reefs during the last four decades, but -doubled on subtropical reefs.

    “Climate change seems to be redistributing coral reefs, the same way it is shifting many other marine species,” says lead author Nichole Price, from Bigelow Laboratory for Ocean Sciences, US.

    “The clarity in this trend is stunning, but we don’t yet know whether the new reefs can support the incredible diversity of tropical systems.”

    The research team has compiled a global database of studies dating back to 1974, when record-keeping began. They hope other scientists will add to it, making it increasingly comprehensive and useful to other research questions.

    See the full U Washington article here .
    See the full COSMOS article here .


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    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.

     
  • richardmitnick 11:14 am on July 10, 2019 Permalink | Reply
    Tags: "Tamu Massif no longer our biggest volcano", And this all means that Mauna Loa on the island of Hawaii should once again be considered the world’s largest single volcano., “The largest volcano in the world is really the mid-ocean ridge system which stretches about 65000 kilometres around the world like stitches on a baseball", COSMOS,   

    From COSMOS Magazine: “Tamu Massif no longer our biggest volcano” 

    Cosmos Magazine bloc

    From COSMOS Magazine

    10 July 2019
    Nick Carne

    1
    Tamu Massif – no longer the biggest, but still impressive. University of Houston

    Tamu Massif was declared the largest single volcano in the world when it was located in the Pacific Ocean about 1600 kilometres east of Japan in 2013 – but now it seems it probably isn’t.

    And the leader of the team that found it is the first to agree.

    “The largest volcano in the world is really the mid-ocean ridge system, which stretches about 65,000 kilometres around the world, like stitches on a baseball,” says William Sager, a geophysicist at the University of Houston, US.

    “This is really a large volcanic system, not a single volcano.”

    In their original paper [Nature Geoscience], Sager and colleagues concluded that Tamu Massif was an enormous shield volcano, formed by far-reaching lava flows emanating from its summit.

    However, new findings by Sager and others, published in the journal Nature Geoscience, conclude that it is a different breed of volcanic mountain altogether.

    A research team from the US, China and Japan analysed magnetic field data over Tamu Massif, finding that magnetic anomalies – perturbations to the field caused by magnetic rocks in the Earth’s crust – resemble those formed at mid-ocean ridge plate boundaries.

    They compiled a magnetic anomaly map using 4.6 million magnetic field readings collected over 54 years along 72,000 kilometres of ship tracks, along with a new grid of magnetic profiles, positioned with modern GPS navigation.

    The map shows that linear magnetic anomalies around Tamu Massif blend into linear anomalies over the mountain itself, implying that the underwater volcano formed by extraordinary mid-ocean ridge crustal formation.

    The new findings also weaken the accepted analogy between eruptions of continental flood basalts and oceanic plateaus because the formation mechanisms are shown to be different, the researchers say.

    Sager is philosophical. “Science is a process and is always changing,” he says. “There were aspects of that explanation that bugged me, so I proposed a new cruise and went back to collect the new magnetic data set that led to this new result.

    “In science, we always have to question what we think we know and to check and double check our assumptions. In the end, it is about getting as close to the truth as possible – no matter where that leads.”

    And this all means that Mauna Loa, on the island of Hawaii, should once again be considered the world’s largest single volcano.

    4
    Mauna Loa Volcano, Hawaii, USA, towers nearly 3,000 m above the much smaller Kilauea Volcano (caldera in left center). Hualalai Volcano is in upper right. In recent years Mauna Loa has not erupted with the frequency of Kilauea, but its 33 historical eruptions have, on average, generated much larger volumes of lava on a daily basis — more than 10 times the lava output from Kilauea’s current Pu`u`O`o eruption. Lava flows on Mauna Loa tend to travel much longer distances in a shorter period of time than those on Kilauea. Thus, warnings and notifications in the first few hours of an eruption are critical for public safety.

    4
    OpenStreetMap – Map of Hawaii

    5
    Map showing relationship of Mauna Loa to other volcanoes that form the island of Hawai’i—the Big Island.

    See the full article here .


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

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