Tagged: COSMOS Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 6:18 pm on September 23, 2020 Permalink | Reply
    Tags: "New photodetector is a shining light", COSMOS, , RMIT University, The RMIT prototype can interpret light ranging from deep ultraviolet to near infrared wavelengths making it sensitive to a broader spectrum than a human eye. And it is less than a nanometre thick., Ultra-thin prototype can see the full spectrum.   

    From RMIT University AU via COSMOS: “New photodetector is a shining light” 

    RMIT AU

    From RMIT University AU

    via

    Cosmos Magazine bloc

    COSMOS

    23 September 2020

    Ultra-thin prototype can see the full spectrum.

    1
    An artist’s impression of RMIT University’s prototype photodetector. Credit: Ella Marushchenko.

    Australian engineers appear to have raised the bar for photodetector technology, developing a device that is incredibly thin but able to see all shades of light.

    Writing in the journal Advanced Materials, researchers from RMIT University, led by Vaishnavi Krishnamurthi, suggest their successful prototype provides new opportunities to integrate electrical and optical components on the same chip.

    Photodetectors, or photosensors, work by converting information carried by light into an electrical signal, and are used in everything from gaming consoles to fibre optic communication.

    However, they currently are unable to sense more than one colour in the one device, Krishnamurthi says, which means they have remained bigger and slower than other technologies, such as the silicon chip, with which they integrate.

    The RMIT prototype can interpret light ranging from deep ultraviolet to near infrared wavelengths, making it sensitive to a broader spectrum than a human eye. And it is less than a nanometre thick.

    Success came from taking a completely different approach.

    Current photodetector technology relies on a stacked structure of three to four layers, but the RMIT team worked out how to use a nanothin layer –a single atom thick – on a chip.

    The material used, tin monosulfide, also is low-cost and naturally abundant, making it attractive for electronics and optoelectronics, says co-author and chief investigator Sumeet Walia.

    “The material allows the device to be extremely sensitive in low-lighting conditions, making it suitable for low-light photography across a wide light spectrum,” he says.

    A major challenge was ensuring electronic and optical properties didn’t deteriorate when the photodetector was shrunk – a technological bottleneck that, the researchers say, had previously prevented miniaturisation of light detection technologies.

    Walia says the team is now looking at industry applications for the photodetector, which can be integrated with existing technologies such as CMOS chips.

    “With further development, we could be looking at applications including more effective motion detection in security cameras at night and faster, more efficient data storage,” he says.

    See the full article here .


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

    Stem Education Coalition

    Success came from taking a completely different approach.

    Current photodetector technology relies on a stacked structure of three to four layers, but the RMIT team worked out how to use a nanothin layer –a single atom thick – on a chip.

    The material used, tin monosulfide, also is low-cost and naturally abundant, making it attractive for electronics and optoelectronics, says co-author and chief investigator Sumeet Walia.

    “The material allows the device to be extremely sensitive in low-lighting conditions, making it suitable for low-light photography across a wide light spectrum,” he says.

    A major challenge was ensuring electronic and optical properties didn’t deteriorate when the photodetector was shrunk – a technological bottleneck that, the researchers say, had previously prevented miniaturisation of light detection technologies.

    Walia says the team is now looking at industry applications for the photodetector, which can be integrated with existing technologies such as CMOS chips.

    “With further development, we could be looking at applications including more effective motion detection in security cameras at night and faster, more efficient data storage,” he says.

     
  • richardmitnick 8:53 am on September 15, 2020 Permalink | Reply
    Tags: "Australia re-enters the space race", COSMOS, DEWC Systems, Each rocket will be a Netherlands-designed 2-stage DART., Gilmour Space, Southern Launch, The ability to launch satellites from Australia will be a return to a past capability.   

    From COSMOS: “Australia re-enters the space race” 

    Cosmos Magazine bloc

    From COSMOS

    14 September 2020
    Ben Lewis

    SA-based Southern Launch begins rocket test program.

    South Australia’s west coast will roar with the sound of rocket launches this week, as start-up Southern Launch begins its test program with two sub-orbital rockets.

    1
    Southern Launch apparatus and model of DART. Credit: Southern Launch.

    It will be a significant moment for Australia’s space industry – the next chapter in a history of rocket launches extending over six decades. It’s also the first tests by Southern Launch, a private company founded in 2017 to establish a site in South Australia for orbital rocket launches.

    The launch will take place near the Indigenous community of Koonibba, around 8 hours drive from Adelaide, where Southern Launch has established a testing range. Launching northwards, each rocket will be a Netherlands-designed 2-stage DART about 3.4 metres long and weighing 34 kilograms. In just 6 seconds of rocket burn they will scream to speeds of Mach 5. The test rockets won’t reach orbit, however, peaking around 85km above Earth.

    They will be carrying a payload though – a miniature probe designed and built by DEWC Systems, an Australian electronic warfare engineering company. After reaching apogee, DEWC-SP1, as the payload has been dubbed, will descend to Earth under parachute. As it comes down, the package of antennas and sensors will perform a sensing mission, as well as being a test of withstanding the 50g of force during launch.

    Once landed, the payload will be collected by DEWC Systems crew escorted by a local Aboriginal cultural monitor.

    “This event is more than just Australia’s first launch, but a testament to Australian companies coming together with our international partners to push the boundaries of the conceivable and inspire future generations to be spacefarers,” says Southern Launch CEO Lloyd Damp.

    “The ability to launch satellites from Australia will be a return to a past capability, that has big implications for our future,” says Swinburne University astronomer Alan Duffy*.

    “We can decide when and where to launch as a nation, allowing us to quickly respond and service a global space industry worth US$600bn by 2030. Our space industry is growing at a startling rate, and launching rockets is a small, but crucial, part of the industry.”

    The launch window opens on Monday 14 September, through to Sunday 20 September. During the window there are two launches planned. Should weather prevent them from going ahead, there is a backup launch window a week later.

    A company spokesperson told Cosmos the launches will be live streamed on Southern Launch’s social media accounts.

    2
    The DART test profile. Credit: Southern Launch.

    Engaging with Indigenous community vital

    The land for the test is leased from the Koonibba Community Aboriginal Corporation, however the partnership between Southern Launch and the local community goes beyond the lease and cultural monitors.

    Southern Launch is working with the Koonibba community to provide opportunities for them to contribute to the project, the company says, having actively worked with local Indigenous people throughout the whole project. The front section of the DART rocket will feature artwork created by local community members as recognition of the partnership.

    “Our people continue to have a strong connection with the land, the sea and the sky, so with Southern Launch developing a rocket test range on our lands, we are excited to develop a partnership role in developing Australia’s space future,” says Koonibba Community Aboriginal Corporation CEO Corey McLennan.

    “Working closely with local Indigenous groups is crucial for the space sector as they often own the remote, isolated sites which are critical to safely launching rockets,” says Duffy.

    “But more than that we want the exciting opportunities of space to be accessible to all Australians, and having that connection to the projects underway will inspire and provide access to the local groups to join that growing space workforce.”

    Continuing a history of Australian rockets

    This is far from the first rocket launch in Australia, or even South Australia. During the 1950s and 1960s Woomera played host to launches by the United Kingdom and European Launcher Development Organisation (a precursor to ESA), and for a time was the second busiest rocket range in the world.

    Then, in 1967 Australia became just the third nation to design and deploy its own orbital satellite, with the launch of WRESAT.

    3
    WRESAT. Weapons Research Establishment.

    Finally, in 1971, the United Kingdom launched the Prospero satellite into low-earth orbit from Woomera – the most recent time a satellite was launched from Australia.

    3
    UK Prospero satellite

    However, that should soon change, with Southern Launch and Equatorial Launch Australia both pushing ahead with establishing launch facilities. Additionally, Queensland company Gilmour Space expect to begin launching their Eris rocket in 2022.

    Ultimately Southern Launch plan to establish a launch complex at Whalers Way, near the South Australian town of Port Lincoln. From this southerly point Southern Launch can offer sun-synchronous or polar orbital launches.

    “In these types of orbits, a satellite passes over the same part of the Earth with the Sun in the same position, allowing for the same illumination of the ground,” says Duffy.

    “That makes it easy to see features on the ground change over time, such as the growth (or loss!) of forests or fluctuations in water bodies all without having to worry about changing shadows or other complications that a different alignment of satellite-Earth-Sun can bring.

    “The ability to deliver that service, be able to launch over a sea where there’s no risk of hitting populated areas, and in an area that doesn’t see hurricanes or extreme weather, is a global opportunity for Australia.”

    *Alan Duffy is Lead Scientist of the Royal Institution of Australia.

    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 9:38 am on September 14, 2020 Permalink | Reply
    Tags: "The basin" is a regime- a set of patterns and occurrences., "What tipping points are telling us", , “Planetary boundaries”, COSMOS, Once we cross a tipping point the new "basin" may be too large to escape.   

    From Arizona State University via COSMOS: “What tipping points are telling us” 


    From Arizona State University

    via

    Cosmos Magazine bloc

    COSMOS

    11 September 2020
    Andrew Bernier

    Why we need to understand them and respond.

    1
    Fire is a classic example of a tipping point. Credit: Andrew Merry / Getty Images.

    Lately, you may have heard someone say that we have reached a “tipping point.” This year alone, with the economic downturn caused by the Covid-19 pandemic and the sustained civil unrest sparked by the killing of George Floyd by a Minneapolis police officer, we have witnessed dramatic shifts in our social and economic states of being.

    These events may even have resulted in you or someone you know reaching a personal tipping point, such as the loss of a job or a large rift in a family regarding social perspectives. Big or small, these shifts — spurred by disruptions — indicate that in some way a point between the way things were in the past and the way they’ll be in the future has been met and passed.

    Ecosystems are also subject to disturbances and major shifts. A wildfire clears a forest, creating conditions for new tree species. Agricultural runoff pollutes local waters, depleting the oxygen fish need to thrive.

    Sometimes the change that is taking place is relatively small and reversible. But sometimes the change is large and extremely difficult, if not impossible, to reverse. It’s as though the entire system has taken a plunge over the edge of a precipice to a new place. That, in essence, is what a tipping point is.

    Being aware of when systems are headed toward this kind of change is the first step to being able to avoid undesirable plunges, encourage desirable ones or nudge systems that are in an undesirable state toward a desirable one.

    Visualising Tipping Points

    In Resilience Thinking: Sustaining Ecosystems and People in a Changing World, Brian Walker, a resilience researcher with Australian National University and the Commonwealth Scientific and Industrial Organisation, and science writer David Salt offer a mental picture to help visualise a tipping point: They describe a system’s state of being as a ball rolling around in a basin where the depth and diameter is constantly changing and the ball is adjusting its movements accordingly.

    2

    The basin is a regime, a set of patterns and occurrences. The edge of the basin is the tipping point — the point at which the ball can leave the basin entirely and enters an entirely new state. The deeper and wider the basin, the more likely the ball will stay in it, even though it’s in constant motion.

    A basin’s width and depth are always changing due to variables such as events (such as demonstrations), levels of something (such as greenhouse gases in the atmosphere) or public sentiment (such as attitudes toward wearing masks). These variables interact with feedback loops, in which the effects of a change in a system themselves affect the system.

    Feedback loops come in two types. Balancing feedback loops help temper the rate of change in a system. Reinforcing feedback loops speed up the change. If reinforcing loops outweigh balancing loops, the system may flip over the edge of the basin and into a new regime.

    Planetary Points

    In 2009, Johan Rockström, executive director of the Stockholm Resilience Centre at Stockholm University, and colleagues introduced nine “planetary boundaries” [Ecology and Society] — identifying what they call the “safe operating space for humanity” in areas of climate change, biogeochemical nitrogen and stratospheric ozone, among other critical ecological systems humans depend on. The team assigned specific boundaries for seven of these.

    Originally they wrote that we had passed three of them (nitrogen biochemical flows, biodiversity loss and climate change) and were approaching others at an increasing pace. In a 2015 update [Science], they included land-system change and phosphorus biochemical flows boundaries among those being passed. While they don’t say we’ve gone over any tipping points, exceeding these boundaries weakens balancing feedback loops and could indicate that the system is headed toward the edge of the basin.

    Focusing on climate change, there is some temperature at which ecosystems reach tipping points. Estimates of what that is change as scientists collect more data. Last year in the scientific journalNature, Timothy Lenton, director of the Global Systems Institute at the University of Exeter and colleagues provided evidence that myriad ecological systems will undergo regime shifts if planetary warming exceeds the tipping point of 1.5 °C (2.7 °F). This number is lower than goals set to limit warming at 2 °C and current projections of 3 °C.

    “In our view, the evidence from tipping points alone suggests that we are in a state of planetary emergency: both the risk and urgency of the situation are acute,” they wrote. Although acquiescing that we already may be past the point of no return on climate-related regime changes, they observe the reinforcing feedback loops can still be slowed, reducing planetary harm. They call for international action, noting that “the rate at which damage accumulates from tipping — and hence the risk posed — could still be under our control to some extent.”

    Why Think About Tipping Points?

    Thinking in terms of tipping points is a worthy endeavor because it provides a clear picture of variables and risks that decision makers can use to craft policies.

    To start, decision makers need to decide whether we should stay in a particular situation or flip the system into a new basin and adopt a new regime. In the case of climate change, wanting things to stay the same would involve heeding identified greenhouse gas thresholds.

    Once that decision is made, the next step is to figure out how to achieve the goal set in the first step. As policy makers debate how to mitigate climate change, options include reducing reinforcing feedback loops (for example, by reducing the amount of greenhouse gas emissions produced) or increasing balancing feedback loops (for example, by reducing deforestation and actively restoring carbon sinks).

    With limited resources to do both, Donella Meadows, in her landmark work Thinking in Systems,says the more effective decision is to reduce reinforcing feedback loops before increasing balancing feedback loops.

    Lenton and his colleagues, for their part, suggested that it might be possible to avoid the regime shifts they describe by stabilising the concentration of greenhouse gases in the atmosphere within 30 years. At the same time, they admitted that there’s a chance we may have already gone over the edge.

    One example of wanting to flip to a new regime is currently unfolding, as seen in the global protests in response to police killing unarmed black people. It could be said the killing of George Floyd was the tipping point, though his killing is one of many in a long succession.

    Right now we appear to be in the cascading effects of entering a new regime, be it protests, social media discord or city council resolutions regarding police funding. Crafting law and policies that foster social justice, along with reforms to police budgeting, would keep the system in this new regime of racial equality. If not enacted, the system can flip back to the old regime.

    Once we cross a tipping point, the new basin may be too large to escape. And even if we want to go back, the original basin may now be so altered that the regime we once knew, with its familiar patterns and behaviors, is no more.

    In the age of Covid-19 and talk about when things will go back to “normal,” those who argue we cannot go back to what once was for various reasons — be it ecological harm, economic inequality and/or social injustice — may be right simply because what was normal may no longer exist. Time will tell what visiting restaurants, salons and movie theaters will be like a year from now — but there’s good chance it won’t be like a year ago.

    Ecologically, we see this when a forest recovers after a fire. Vegetation returns, but it’s mostly new tree species better suited for damaged soil.

    Similarly, as our planet warms, efforts to return to the world we knew before climate change may be beyond our capacity. To the extent this is the case, our job becomes, not avoiding change — which may be impossible — but figuring out and adapting to the new circumstances.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition


    ASU is the largest public university by enrollment in the United States. Founded in 1885 as the Territorial Normal School at Tempe, the school underwent a series of changes in name and curriculum. In 1945 it was placed under control of the Arizona Board of Regents and was renamed Arizona State College. A 1958 statewide ballot measure gave the university its present name.
    ASU is classified as a research university with very high research activity (RU/VH) by the Carnegie Classification of Institutions of Higher Education, one of 78 U.S. public universities with that designation. Since 2005 ASU has been ranked among the Top 50 research universities, public and private, in the U.S. based on research output, innovation, development, research expenditures, number of awarded patents and awarded research grant proposals. The Center for Measuring University Performance currently ranks ASU 31st among top U.S. public research universities.

    ASU awards bachelor’s, master’s and doctoral degrees in 16 colleges and schools on five locations: the original Tempe campus, the West campus in northwest Phoenix, the Polytechnic campus in eastern Mesa, the Downtown Phoenix campus and the Colleges at Lake Havasu City. ASU’s “Online campus” offers 41 undergraduate degrees, 37 graduate degrees and 14 graduate or undergraduate certificates, earning ASU a Top 10 rating for Best Online Programs. ASU also offers international academic program partnerships in Mexico, Europe and China. ASU is accredited as a single institution by The Higher Learning Commission.

     
  • richardmitnick 10:59 am on September 8, 2020 Permalink | Reply
    Tags: "Grains of dust revise Solar System history", , Asteroids like Vesta formed in the inner Solar System are built of materials with a different array of chemical isotopes than those from asteroids which formed farther out in the Solar System., , , , Carbonaceous chondrite meteorites, , COSMOS, Such meteorites are chips off asteroids that have been blasted into space by collisions only to eventually fall to Earth where they can be examined in laboratories.,   

    From UC Davis via COSMOS: “Grains of dust revise Solar System history” 

    UC Davis bloc

    From UC Davis

    via

    Cosmos Magazine bloc

    COSMOS

    8 September 2020
    Richard A Lovett

    Scientists study the chemical composition of meteorites.

    1
    Credit: Science Photo Library – andrzej/Getty Images.

    Asteroids that formed far out in the Solar System appear to contain dust grains that themselves condensed from the infant Solar System’s protoplanetary disc much closer to the Sun, scientists say.

    That means this dust was somehow transported from the inner reaches of the disc to its outer reaches, says Curtis Williams, a geochemist at the University of California, Davis. Once there, it mixed with material that condensed from that part of the disc to form larger objects that eventually became asteroids.

    In a study described in the journal PNAS, Williams and a team of US and Japanese researchers found these dust grains in a type of meteorite known as carbonaceous chondrites.

    Such meteorites are chips off asteroids that have been blasted into space by collisions, only to eventually fall to Earth, where they can be examined in laboratories.

    Previous studies had found that rocks from Earth and Mars, as well as asteroids like Vesta, which formed in the inner Solar System, are built of materials with a different array of chemical isotopes than those from asteroids known to have formed farther out in the Solar System.

    Based on that, scientists had assumed that inner Solar System dust – which is different from outer Solar System dust because it condensed in hotter regions closer to the Sun – did not mix with outer Solar System dust. Instead, they assumed, it remained relatively close to the Sun.

    The reason for this separation, they assumed, was the formation of the giant planet Jupiter, whose enormous gravity created a gap through which dust could not migrate. This, they assumed, divided the young Solar System into two distinct parts.

    In the new study, however, Williams’s team delved into 30 carbonaceous chondrites and looked at their individual components. “They have microcomponents, called inclusions,” Williams says.

    Looking carefully at isotopes in these sand-grain-sized inclusions, he says, his team found that some formed in the outer Solar System, but some must have formed closer to the Sun, then migrated outward before accreting into a larger body.

    Since Jupiter is believed to have already been present at the time these grains dispersed, Williams says, “that has big implications. Either Jupiter was not a complete barrier, or these particles somehow jumped over Jupiter and landed in the outer Solar System.”

    It’s an important finding partly because it will help planet-formation modellers better understand how dust grains migrate around a protoplanetary disk – including one in which giant planets are forming – before being incorporated into larger objects.

    But it will also help modellers figure out important aspects of conditions in these protoplanetary discs, including the viscosity and turbulence of their gas and dust.

    “That plays a role in how you build planets,” Williams says.

    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 Davis Campus

    The University of California, Davis, is a major public research university located in Davis, California, just west of Sacramento. It encompasses 5,300 acres of land, making it the second largest UC campus in terms of land ownership, after UC Merced.

     
  • richardmitnick 11:10 am on September 1, 2020 Permalink | Reply
    Tags: "The spread and impact of marine structures", All marine construction replaces natural habitats and can modify environmental conditions critical to habitat persistence at regional scales., , COSMOS, , More than 32000 square kilometres of the world’s marine environment has been modified by human construction and this is likely to reach nearly 40000 by 2028 according to a new global assessment., Study quantifies human development in the oceans., Sydney Institute of Marine Science, When flow-on effects in surrounding areas are included the footprint is actually two million square kilometres.   

    From Sydney Institute of Marine Science via COSMOS: “The spread and impact of marine structures” 

    1

    From Sydney Institute of Marine Science

    via

    Cosmos Magazine bloc

    COSMOS

    1 September 2020

    Study quantifies human development in the oceans.

    1
    Credit: SumitAwinash / Wikimedia Commons.

    More than 32,000 square kilometres of the world’s marine environment has been modified by human construction and this is likely to reach nearly 40,000 by 2028, according to a new global assessment.

    When flow-on effects in surrounding areas are included, the footprint is actually two million square kilometres, or more than 0.5% of the total marine area. Development mostly occurs near coasts, which are the most biodiverse and biologically productive environments.

    The area directly affected is greater than the global area of some natural marine habitats, such as mangrove forests and seagrass beds, the researchers write in a paper in the journal Nature Sustainability.

    And just to underline the complexity of the problem, some of the modification is caused by initiatives designed to help the environment, such as wind farms.

    “The proliferation of marine built structures shown here provides a suite of ecological, social and economic benefits – for example, the expansion of renewable sources of energy in the oceans can minimise greenhouse gas emissions,” the authors write.

    “In addition, energy extraction infrastructure may sometimes serve to benefit sensitive habitats due to the fishing exclusion zones set up around them and even act as focal points for restoration activities.

    “Nevertheless, all marine construction replaces natural habitats and can modify environmental conditions critical to habitat persistence at regional scales.”

    The research was led by Ana Bugnot from the Sydney Institute of Marine Science and brought together scientists from Australia, Italy, the US and the UK.

    2
    Aquaculture farms in China’s Liaoning province. Credit: NASA Earth Observatory.

    They gathered data and made calculations to estimate the physical footprint and area of seascape modification around marine construction as of 2018, including future trends.

    This included 11 categories of activity: gas and oil rigs, subsea pipelines, wind farms, wave and tidal farms, telecommunication cables, aquaculture, commercial ports, tunnels and bridges, breakwaters, recreational marinas, and artificial reefs.

    “The numbers are alarming,” Bugnot says. “For example, infrastructure for power and aquaculture, including cables and tunnels, is projected to increase by 50 to 70% by 2028, yet this is an underestimate. There is a dearth of information on ocean development, due to poor regulation of this in many parts of the world.”

    This is not a new thing, of course. As the paper acknowledges, humans have been building marine infrastructure to support marine traffic for 4000 years.

    But things have “ramped up” since the middle of last century, Bugot says, with both positive and negative results.

    “For example, while artificial reefs have been used as ‘sacrificial habitat’ to drive tourism and deter fishing, this infrastructure can also impact sensitive natural habitats like seagrasses, mudflats and saltmarshes, consequently affecting water quality.”

    Land reclamation is an emerging trend, with the researchers identifying 479 human-made islands in marine environments worldwide, with some now moving into deeper waters up to 500 kilometres offshore.

    Others are built in groups, including The World (United Arab Emirates, 300 islands) and the Fortress Islands (Russia, 19 islands).

    “Ongoing demands for space to accommodate an increasing coastal population and the need for ‘designer islands’ to host climate refugees means that land reclamation will continue to spread and occupy a substantial extension of the marine environment, with many associated impacts,” the report says.

    The researchers say their study is the first to quantify the extent of human impact.

    Because of the difficulty of accurately mapping structures, to date “the most complete assessments of anthropogenic impacts on the oceans and ocean health have relied upon proxies for marine construction, such as human population density, mariculture production and night light intensity from oil and gas platforms”, they write.

    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 9:53 am on August 21, 2020 Permalink | Reply
    Tags: "Coral reefs are trying to recover", , COSMOS, , , Report reveals some hope for the Great Barrier Reef.   

    From COSMOS: “Coral reefs are trying to recover” 

    Cosmos Magazine bloc

    From COSMOS

    21 August 2020
    Natalie Parletta

    Report reveals some hope for the Great Barrier Reef.

    1
    Helix Reef and some others in the GBR’s central region appear unaffected by bleaching and maintain healthy coral assemblages. Credit: Australian Institute of Marine Science.

    Coral cover has shown small signs of recovery on two thirds of reefs surveyed along the Great Barrier Reef – but it’s a bittersweet victory amongst continued onslaught by bleaching, crown-of-thorn starfish outbreaks and tropical cyclones.

    And the full impact of last year’s mass coral bleaching event is yet to be revealed, according to an annual report from the Australian Institute of Marine Science (AIMS), which has been monitoring the vulnerable World Heritage-listed site for more than three decades.

    “The third mass coral bleaching in five years unfolded in late summer, and this event may well have reversed the gains in hard coral cover,” says project lead Mike Emslie from AIMS, based in Townsville, Queensland.

    The impact of bleaching, which results from prolonged high sea temperatures, continues weeks to months afterwards so it’s not fully covered by the report, which is based on surveys conducted between September 2019 and June 2020.

    2
    Crown-of-thorns starfish continue to decimate coral on many reefs in the southern Swain sector. Credit: AIMS.

    The Great Barrier Reef is the largest living structure on the planet. For now, its revival is encouraging, says Emslie, but there’s a long way to go and it needs more time to recover between damaging events, which are occurring more frequently.

    “Full recovery of coral reefs takes years to decades and requires many years without subsequent disturbances”, he explains, and although the Great Barrier Reef has shown an ability to start coming back, “such resilience clearly has limits”.

    At the time of the survey, the percentage of live hard coral cover along the seafloor – a proxy for reef health – varied considerably among the 86 reefs surveyed.

    The dynamic southern region, extending down to Rockhampton, had the most average cover at 24%, an increase of 1% and just over half of what it was in 1988. This was a slight setback from the reef’s remarkable recovery from 9% in 2011 to 32% in 2017 after crown-of-thorns starfish outbreaks.

    In the central region, between Hinchinbrook Island and Mackay, hard coral cover increased on average from 12% in 2019 to 14% in 2020. This area also had low numbers of crown-of-thorns starfish, likely due to a control program.

    3
    Some reefs in the northern region, mostly inshore, have yet to recover from recent disturbances. Credit: AIMS.

    Coral cover in the Northern Great Barrier Reef, north of Cooktown, remained stable at 15% after increasing from 12% since 2017.

    The team made their estimates using manta tow surveys, a standard technique that involves visual categorisation of percentage cover as low (0-10%) to extremely high (75-100%), averaged from a series of two-minute tows, each covering around 2000 square metres. AIMS deems coral as healthy with as low as 30% to 50% cover.

    Encouragingly, the survey also found that coral trout have continued to grow larger in size and number in a marine park rezoned in 2004 compared to reefs where fishing is still allowed. These Green Zones had nearly twice as many fish than the latter Blue Zones.

    This suggests “well-managed and resourced networks of no-take marine reserves have the desired conservation benefits,” says Emslie, and further, “larger trout inside no-take marine reserves produce more babies, which can help re-seed populations in areas that are open to fishing”.

    Some of the larvae from the trout, one of the most valuable species for recreational anglers and commercial fishers, are moved to the Blue Zones.

    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 8:56 am on August 17, 2020 Permalink | Reply
    Tags: "Alfred Wegener and the continental drift", , COSMOS, , , , , The Earth Institute’s State of the Planet blog   

    From COSMOS: “Alfred Wegener and the continental drift” 

    Cosmos Magazine bloc

    From COSMOS

    14 August 2020
    Jeff Glorfeld

    Astronomer’s geological theory didn’t please everyone.

    1
    Alfred Wegener during a 1912-1913 expedition to Greenland. Credit: Alfred Wegener Institute, via Wikimedia Commons.

    The Earth Institute’s State of the Planet blog recently featured a story headlined 8 Surprising Facts About Marie Tharp, Mapmaker Extraordinaire.

    The institute, part of New York’s Columbia University, was celebrating the centenary of the birth of the American geologist and oceanographic cartographer who spent most of her career working at Columbia’s Lamont Geological Observatory.

    Beginning in the early 1950s, Tharp, who died on 23 August 2006, “created some of the world’s first maps of the ocean floor”, the blog says.

    Her work led to the acceptance of the concepts of plate tectonics and continental drift, and a 2016 article about her in Smithsonian Magazine was headlined: Seeing is believing: How Marie Tharp changed geology forever.

    The tectonic plates of the world were mapped in 1996, USGS.

    It describes how Tharp’s findings were initially disbelieved and even ridiculed. One of her research partners, geologist Bruce Heezen, rejected her ideas as “girl talk”.

    Heezen, who would eventually come around to accepting Tharp’s analysis, claimed “that it sounded like the ‘debunked’ continental drift hypothesis as proposed by Alfred Wegener in 1912”, says a recent article in Forbes magazine.

    Just as Tharp had to overcome resistance to her ideas, reaction to Wegener’s theory “was almost uniformly hostile, and often exceptionally harsh and scathing”, says an article published by the University of California Museum of Paleontology (UCMP).

    Wegener expanded this “debunked” hypothesis in 1915 into what NASA calls “one of the most influential and controversial books in the history of science: The Origin of Continents and Oceans.

    3
    Wegener featured on an Austrian stamp. Credit: raclro / Getty Images.

    Wegener was born in Berlin, Germany, on 1 November 1880. Mott T Greene, author of the 2015 biography Alfred Wegener: Science, Exploration, and the Theory of Continental Drift, says he formulated the geological theory of continental drift but he wasn’t a geologist; he was an astronomer who specialised in atmospheric physics.

    In 1912, when he proposed his theory of continental displacement, he was 31 and teaching physics and astronomy at the University of Marburg, in southern Germany, Greene says.

    He was a renowned balloonist (setting the world record in 1906, with his brother Kurt, for time aloft in a free balloon – more than 52 hours), had been a part of a daring expedition to explore the unmapped north-east coast of Greenland, and was the author of a highly regarded textbook, Thermodynamics of the Atmosphere.

    “As important as Wegener’s work on continental drift has turned out to be,” Greene says, “it was largely a sideline to his principal career in atmospheric physics, geophysics and paleo-climatology.”

    In 2001, as part of its Earth Observatory website, NASA produced a seven-part series on Wegener.

    What began in 1910 as a simple observation, NASA says, became a lifelong fascination. “‘Doesn’t the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined?’ wrote Wegener to his future wife in December 1910. ‘This is an idea I’ll have to pursue’.”

    4
    Credit: Lotse / Wikimedia Commons.

    He searched out other papers about such continental coincidences. “As he read, his earlier conjecture that the continents had once been joined became a conviction he would boldly champion for the rest of his life.”

    In 1915 Wegener wrote The Origin of Continents and Oceans, but because of World War I it went unnoticed outside Germany, NASA says.

    “In 1922, however, a third (revised) edition was translated into English, French, Russian, Spanish and Swedish, pushing Wegener’s theory of continental drift to the forefront of debate in the earth sciences.”

    By then, NASA says, “Wegener was citing geological evidence that some 300 million years ago all the continents had been joined in a supercontinent stretching from pole to pole. He called it Pangaea (all lands), and said it began to break up about 200 million years ago, when the continents started moving to their current positions.”

    Although Wegener’s hypothesis proved to be largely correct, the UCMP notes several problems with it that led to the general lack of support.

    “Wegener had no convincing mechanism for how the continents might move,” it says. He thought the continents were “moving through the earth’s crust, like icebreakers plowing through ice sheets, and that centrifugal and tidal forces were responsible for moving the continents”.

    In 1930 Wegener returned to Greenland, planning to establish three observation posts. However, as the NASA series describes, the expedition was beset by bad weather, and Wegener perished on the ice, shortly after celebrating his 50th birthday.

    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 9:46 am on August 12, 2020 Permalink | Reply
    Tags: "Tracking the birth of a supercontinent", A dipping Moho, , COSMOS, Earth is the only planet we know of with plate tectonics., , , , , , The creation of supercontinent Nuna., We studied an area geologists call the Ordos block which is part of the North China craton.   

    From Macquarie University via COSMOS: “Tracking the birth of a supercontinent” 

    From Macquarie University

    via

    Cosmos Magazine bloc

    COSMOS

    7 August 2020
    Huaiyu Yuan, Macquarie University

    Scientists find some old and intriguing clues.

    1
    The present landscape near Dongshen, China. Credit: Wan et al., Author provided.

    Far beneath the city of Dongshen in northern China, we have discovered what may be the 2 billion-year-old birthmarks of Earth’s first supercontinent.

    An ancient dipping structure in the planet’s crust appears to be a trace of an early collision between two continental masses like the one that created the Himalaya – and may record the origin of the global system of plate tectonics that persists today.

    The tectonic plates of the world were mapped in 1996, USGS.

    When did plate tectonics begin?

    The theory of plate tectonics is one of the key scientific advances of the past century. It explains how Earth’s crust is made of enormous rocky “plates” floating on the planet’s molten interior, which slowly move around. These movements are responsible for earthquakes and mountain ranges.

    Earth is the only planet we know of with plate tectonics. The motion of the plates gradually cycles elements between the interior of the planet, the surface and the atmosphere, generating the resources and environment that make human life possible.

    At some point in the deep past, plate tectonics began as Earth cooled. When this happened, however, has remained controversial. Dates spanning three-quarters of Earth’s history have been proposed, from the Hadean eon (between 4.5 billion and 4 billion years ago) to the late Proterozoic eon (less than a billion years ago).

    Many of these dates come from isolated samples showing the existence of single plates. However, plate tectonics is a global phenomenon in which plates interact with each other. We studied one of these early interactions: a collision in what is now northern China, in which the edge of one plate was thrust upwards while the other was pushed down.

    The dipping Moho

    Our new study suggests plate tectonics began globally somewhere between 2 billion and 1.8 billion years ago. The research, published in Science Advances, was carried out by an international team from China, Germany and Australia, led by Wan, Bo from the Institute of Geology and Geophysics of the Chinese Academy of Sciences (IGGCAS).

    2
    The global network of ancient collisions that show the creation of supercontinent Nuna. Credit: Wan et al. / Science Advances, Author provided.

    We studied an area geologists call the Ordos block, which is part of the North China craton, a very stable chunk of the Asian continent that takes in parts of northeastern China, Mongolia and North Korea.

    In April 2019, we deployed 609 seismic recording stations spaced every 500 metres along a 300-kilometre line. By combining the earthquake data from these stations, we were able to form a detailed picture of Earth’s crust in this area.

    Beneath the city of Dongsheng, we found a feature called a dipping Moho in which the bottom of Earth’s crust dips from around 35km deep to more than 50km deep over a horizontal distance of only 40km.

    This dipping structure looks nearly identical to what is found beneath the Himalayan mountains, except it is around 2 billion years old.

    A global pattern

    Next, we collected seismic evidence from other studies around the world for similar dipping Moho structures that are about the same age. Putting observations from six continents together, we can form a picture of the creation of the ancient supercontinent Nuna.

    Nuna (sometimes also called Columbia) is believed to have been made up of parts of most of the continents that exist today. If Nuna was the first supercontinent, we can interpret these tectonic collisions that occurred around 2 billion years ago as the oldest evidence of plate tectonics in the global sense. Even though such collisions may have occurred here and there early on, it is likely that plate tectonics did not become a global network until this time.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Macquarie University campus

    Established in 1964, Macquarie University began as a bold experiment in higher education. Built to break from traditions: to be distinctive, progressive, and to be transformational. Today our pioneering history continues to be a source of inspiration as we celebrate our place among the best and brightest minds.

    Recognised internationally, Macquarie University is consistently ranked in the top two per cent of universities in the world* and within the top 10 in Australia*.

    Our research is leading the way in ground-breaking discoveries. Our academics are at the forefront of innovation and, as accomplished researchers, we are embracing the opportunity to tackle the big issues of our time.

    Led by the Vice-Chancellor, Professor S Bruce Dowton, Macquarie is home to five faculties. The fifth and newest – Faculty of Medicine and Health Sciences – was formed in 2014. We are also home to some of Australia’s most exceptional facilities – hubs of innovation that unite our students, researchers, academics and partners to achieve extraordinary things.

    Discover our story.

     
  • richardmitnick 9:40 am on July 6, 2020 Permalink | Reply
    Tags: "The supersizing of quantum physics", , , COSMOS, , , Squeezer table   

    From Australian National University via COSMOS: “The supersizing of quantum physics” 

    ANU Australian National University Bloc

    From Australian National University

    via

    Cosmos Magazine bloc

    COSMOS

    3 July 2020
    Phil Dooley

    Quantum physics is the realm of tiny particles no longer. Scientists at the giant gravitational wave detector LIGO in the US are now measuring the quantum effects of 40-kilogram mirrors used to detect gravitational waves.


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project


    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib

    ESA/eLISA the future of gravitational wave research

    While physicists routinely observe quantum effects in nanometre-scale experiments, LIGO team member Robert Ward says this new level of sensitivity was unmatched in other experiments.

    1
    ANU’s Nutsinee Kijbunchoo (left) and Terry McRae building a squeezer table at LIGO Hanford. Credit: ANU.

    “There’s nowhere else close, nothing like it. That’s as big as my kids!” says Ward, who is part of the OzGrav Research Centre based at the Australian National University (ANU).

    “The reality that we can measure to this level of precision on an instrument that is so large is incredible,” adds his ANU colleague Terry McRae, who recently spent a year installing new componentry at the Livingston site in Louisiana, US.

    Livingston is one of two linked gravitational wave detectors run by the LIGO organisation. Each detector is made of two high-powered laser beams at right angles, bouncing between mirrors four kilometres apart. The second is in Washington State, 3000 kilometres to the northwest.

    The LIGO team has published results in the journal Nature that accurately show quantum correlations between the 40-kilogram mirrors and the laser beam, which at 200 kilowatts is about 2000 times more powerful than a laser cutter.

    For the purpose of detecting gravitational waves, it has used the correlations and manipulated the quantum properties of the system, to reduce noise and make it more sensitive, a technique called quantum squeezing.

    The sensitivity of LIGO is crucial. Although black hole collisions are the most violent events known to humans, the gravitational waves from them reach earth as tiny flickers in space and time. In the triumphant first detections of gravitational waves, LIGO’s mirrors moved about a billionth of the diameter of the atoms making up the mirrors.

    The two-decade story of LIGO is one of tirelessly removing one noise source after another, says ANU’s Nutsinee Kijbunchoo.

    “We’re always trying to do better: sensitivity less than the width of a hair? Not good enough, we have to keep improving,” she says.

    Kijbunchoo worked with McRae on the recent upgrade at Livingston and was amazed to see people banging on parts of the apparatus to try to induce noise, characterise it precisely and work out how to cut it out.

    A recent paper [Physics]announced the new sensitivity levels reached, thanks to the new quantum squeezing system that Kijbunchoo and McRae were involved in installing. The paper estimated that the improvement would lead to a 50% jump in the rate of gravitational wave detections.

    This new paper takes a step back, however, and discusses the significance of the LIGO’s sensitivity, saying in its conclusions that “the measurements presented here represent long-awaited milestones in verifying the role of quantum mechanics in limiting the measurement of small displacements…”.

    Rob Ward says this moment has been a long time coming, citing Russian scientist Braginsky as one of the first to begin thinking [Reviews of Modern Physics] about the quantum limits of measurement in 1996.

    “Now we’ve crossed that threshold, and now we have to start thinking about the quantum mechanics of our test masses (mirrors). We’re being forced to grapple with the quantum mechanics of a human-sized objects,” Ward says.

    The quantum noise has been revealed after an intricate system of suspension wires, feedback systems, laser stabiliser and cooling systems have stabilised the experiment – removing the so-called classical noise.

    3
    Credit: Nutsinee Kijbunchoo ANU.

    You would think all of these vibrations and wobbles could be cut out completely, but quantum noise is a fundamental property of a system, first expressed by Heisenberg in the famous Uncertainty Principle, which lays out that measurements have limits to their precision, beyond which you cannot pass, no matter how cold, stable or isolated your experiment is.

    But there is a loophole: these measurements come in pairs, and the uncertainty is distributed between the pairs, and can be shifted from one quantity to the other.

    Imagine cleaning the house, which you could measure by how fast it was done, or how clean the house ends up. The quicker the clean-up, the lower the final standard of cleanliness. Or, an exhaustive spring clean could take well past tea time.

    It’s this kind of trade-off that the squeezing system uses – in this case playing off the radiation pressure against the randomness in the arrival time of the photons. The trick is the photons need to be paired – correlated – which enables the quantum link to be leveraged.

    These play into the overall noise differently for different signals, so the LIGO scientists constrain the value of one that will make the experiment most sensitive, say to a neutron star merger, and let the other be a little less certain.

    This is how the LIGO detector achieves sensitivity that is better than non-quantum physics could have imagined – a limit known as the standard quantum limit (SQL).

    These quantum tricks can only be used if the overall noise is infinitesimal, otherwise the pairings become smeared out, and quantum effects can’t be seen.

    This is the case in our everyday world. But now, says Ward, with this exquisite instrument we’re in a realm we’ve never seen before.

    “We never normally see quantum effects of big objects, and we don’t exactly know why, but now we’re getting to that level of precision,” he says. “We’re exploring fundamental questions about reality.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    ANU Campus

    ANU is a world-leading university in Australia’s capital city, Canberra. Our location points to our unique history, ties to the Australian Government and special standing as a resource for the Australian people.

    Our focus on research as an asset, and an approach to education, ensures our graduates are in demand the world-over for their abilities to understand, and apply vision and creativity to addressing complex contemporary challenges.

     
  • richardmitnick 10:04 am on July 2, 2020 Permalink | Reply
    Tags: "A chance to see a planet’s interior", , , , , COSMOS, , The planetary core named TOI 849 b,   

    From University of Warwick via COSMOS: “A chance to see a planet’s interior” 

    From University of Warwick

    via

    Cosmos Magazine bloc

    COSMOS

    2 July 2020

    1
    An artist’s impression of a Neptune-sized planet in the Neptunian Desert. Credit: University of Warwick/Mark Garlick

    Astronomers have discovered the surviving core of a gas giant orbiting a distant star, offering, they say, an unprecedented glimpse into the interior of a planet.

    Writing in the journal Nature, a team led by the University of Warwick, UK, says the core, named TOI 849 b, is the size of Neptune and is likely a gas giant that either was stripped of its gaseous atmosphere or failed to form one in its early life.

    Located 730 light-years away, it orbits so close to its host star that a year is a mere 18 hours and its surface temperature is around 1800 degrees Kelvin.

    “TOI 849 b is the most massive terrestrial planet – that has an earth like density – discovered,” says lead author David Armstrong.

    “We would expect a planet this massive to have accreted large quantities of hydrogen and helium when it formed, growing into something similar to Jupiter.

    “The fact that we don’t see those gases lets us know this is an exposed planetary core. This is the first time that we’ve discovered an intact exposed core of a gas giant around a star.”

    TOI 849 b was found in the Neptunian Desert – a term used, Armstrong says, for a region close to stars where we rarely see planets of Neptune’s mass or larger – by NASA’s Transiting Exoplanet Survey Satellite (TESS).

    NASA/MIT TESS replaced Kepler in search for exoplanets

    It was then analysed using the Harps instrument at the European Southern Observatory’s La Silla Observatory in Chile.

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    This utilises the Doppler effect to measure the mass of exoplanets by measuring their wobble – small movements towards and away from us that register as tiny shifts in the star’s spectrum of light.

    2
    Doppler effect. Iken Edu

    Armstrong and colleague determined that its mass is two to three times higher than Neptune’s and that it is also incredibly dense, with all the material that makes up that mass squashed into an object the same size.

    “While this is an unusually massive planet, it’s a long way from the most massive we know, but it is the most massive we know for its size, and extremely dense for something the size of Neptune, which tells us this planet has a very unusual history,” Armstrong says.

    “The fact that it’s in a strange location for its mass also helps; we don’t see planets with this mass at these short orbital periods.”

    Armstrong says the discovery provides an opportunity “to look at the core of a planet in a way that we can’t do in our own Solar System”.

    “There are still big open questions about the nature of Jupiter’s core, for example, so strange and unusual exoplanets like this give us a window into planet formation that we have no other way to explore.”

    He is also confident researchers will be able to find out more about the planet’s chemical composition.

    “Because TOI 849 b is so close to the star, any remaining atmosphere around the planet has to be constantly replenished from the core,” he says. “So if we can measure that atmosphere then we can get an insight into the composition of the core itself.”
    Cosmos Magazine
    Cosmos

    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 establishment of the The University of Warwick was given approval by the government in 1961 and received its Royal Charter of Incorporation in 1965.

    The idea for a university in Coventry was mooted shortly after the conclusion of the Second World War but it was a bold and imaginative partnership of the City and the County which brought the University into being on a 400-acre site jointly granted by the two authorities. Since then, the University has incorporated the former Coventry College of Education in 1978 and has extended its land holdings by the purchase of adjoining farm land.

    The University initially admitted a small intake of graduate students in 1964 and took its first 450 undergraduates in October 1965. In October 2013, the student population was over 23,000 of which 9,775 are postgraduates. Around a third of the student body comes from overseas and over 120 countries are represented on the campus.

     
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: