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  • richardmitnick 8:10 am on October 7, 2022 Permalink | Reply
    Tags: "How satellites harm astronomy - what’s being done", , , , , , , International Telecommunication Union, , , Square Kilometer Array Observatory (SKAO), The European Southern Observatory   

    From “EarthSky” : “How satellites harm astronomy – what’s being done” 

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    From “EarthSky”

    10.6.22
    Kelly Kizer Whitt

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    Artist’s concept shows the 30,000 planned satellites from the Starlink Generation 2 constellation as of 2022. Different sub-constellations are in different colors. Learn more about how mega constellations of satellites harm astronomy. Image via The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europäische Südsternwarte](EU)(CL).

    You may have heard the growing complaints from astronomers as companies such as SpaceX add more satellites to our sky. Astronomers are not against the communication networks that the satellites provide, but they have valid concerns for the future of ground-based explorations of the universe. And there is only so much astronomers can do on their own to mitigate the problem. A report from the 2021 conference for Dark and Quiet Skies stated:

    “The advantages to society that the communication constellations are offering cannot be disputed, but their impact on the pristine appearance of the night sky and on astronomy must be considered with great attention because they affect both the cultural heritage of humanity and the progress of science.”

    How satellites harm astronomy: The problem with increasing satellites

    Astronomers face a variety of problems with the increasing numbers of satellites filling low-Earth orbit. Optical and near-infrared telescopes feel the impacts from these mega constellations. Some of the biggest are on wide-field surveys, longer exposures and evening and morning twilight observations when sunlight reflects off the satellites. The European Southern Observatory, the European Space Organization, reported these findings from a 2021 study [Astronomy & Astrophysics(below)]:

    “The effect is more pronounced for long exposures, up to three percent of which may be ruined during twilight. The study also found that the greatest impact of new satellite constellations will be on wide-field surveys made by telescopes such as the US National Science Foundation’s Vera C. Rubin Observatory. Up to 30-50 percent of twilight observations being seriously impacted.”

    And because we’re talking about scientists, of course they’ve officially started studying the issue. Studies in 2020 [ Astronomy and Astrophysics (below)] and 2021 [Astronomy & Astrophysics (below)] showed the impact on optical and near-infrared telescopes. They found that telescopes such as the Very Large Telescope (VLT) and the future Extremely Large Telescope (ELT) will be “moderately affected” by new satellite mega constellations.

    Some telescopes, such as the Rubin Observatory under construction in Chile, will experience greater impacts. These telescopes scan wide areas quickly. This makes them crucial in spotting supernovae or potentially dangerous asteroids.

    The impact on radio astronomy

    Radio astronomy has its own particular concerns. Radio telescopes don’t look in the visible wavelengths of the electromagnetic spectrum, so it’s not the same “visibility” issue. For radio telescopes, the main problem is with the signals the satellites transmit down to Earth. Plus, radio telescopes aren’t only looking at dim lights in the night. They’re looking at the sky 24/7. So, satellites are a problem every hour of the day, not just at twilight.

    But there’s more. A satellite’s signal is much, much stronger than the faint background sources that radio astronomers study. And a satellite doesn’t have to pass right in front of the object of study to cause interference. Satellite sources in a radio telescope’s “peripheral vision” also interfere.

    The European Southern Observatory (ESO) described the potential impact of satellites on radio astronomy:

    “They amount to hundreds of radio transmitters above the observatory’s horizon, which will affect the measurements made by our highly sensitive radio telescopes.”

    Radio astronomy has some protection against interference. Radio astronomers call this spectrum management, and the Radio Communication Sector of the International Telecommunication Union (ITU-R) create regulations that help protect astronomers studying certain frequency bands and wavelength ranges. But the recent large constellations of telecommunication satellites pose new threats.

    One recommendation is for satellite designs that avoid direct illumination of radio telescopes and radio-quiet zones. Also, the cumulative background electromagnetic noise created by satellite constellations should be kept below the limit already agreed to by the ITU.

    Philip Diamond of the Square Kilometer Array Observatory (SKAO) summed up the issue:

    “The deployment of thousands of satellites in low-Earth orbit in the coming years will inevitably change this landscape by creating a much larger number of fast-moving radio sources in the sky, which will interfere with humanity’s ability to explore the universe.”

    What can visual astronomers do?

    It would be great if a computer program could quickly eliminate all the satellites trails or interference from astronomers’ data. But it’s not quite that easy. One recent report outlined the problem of low-Earth orbit satellites on images:

    “They leave traces of their transit on astronomical images, significantly decreasing the scientific usability of the collected data. Post-processing of the affected images only partially remedies the problem: the brighter trails may saturate the detectors, making portions of images unusable, while the removal of the fainter trails leaves residual effects that seriously affect important scientific programs, as, for example, statistical, automated surveys of faint galaxies.”

    But there are some things astronomers could do, and have been doing thus far. They can avoid observing where satellites will pass, limit observations to areas of the sky that are in Earth’s shadow and close the shutter precisely when a satellite crosses the field of view. This all takes a lot of knowledge of the paths of thousands of satellites and plenty of pre-planning. Obviously, these are not realistic possibilities for many situations.

    What can satellite operators do?

    Another way to mitigate the problem is for satellite operators to adjust their designs (for example, darkening the satellite). They can also operate the satellites in a way that would raise their orbits out of vision of the optical telescopes, deorbit satellites that are no longer functioning, as well as other considerations for minimizing disruption. In several cases, the satellite operators have shown willingness to cooperate on this.

    Unfortunately, the companies planning these mega satellite constellations did not warn astronomers in advance. So many of these satellites were already filling the skies without any restrictions as astronomers scrambled to figure out how to save their observations and lessen the impact. Their efforts led to the creation of a new center that is collecting data from the community, astronomers and the general public, among others, to learn more about the effects on the night sky.

    Official efforts to reduce harm from satellites

    In June 2022, the International Astronomical Union (IAU), together with the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab) and SKAO, opened the Center for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (CPS). The center highlights the dramatically increased risk of interference from low-Earth orbit satellites – both planned and already in orbit – that provide broadband services. On their website, you can see a running total of the number of operational constellation satellites (2,994) and the number of planned constellation satellites (431,713), among other stats.

    Co-director Connie Walker from NOIRLab said:

    “Three years ago SpaceX launched the first 60 Starlink satellites. The number of satellites from this and other companies is increasing exponentially and impacting the field of astronomy. During the last two years, four key workshops identified issues and recommended mitigation solutions with the help of astronomers, satellite industry folk, space lawyers and people from the general community worldwide.”

    In the peer-reviewed journal Air & Space Law [below], scientists at ESO published a study in September 2021 extensively warning of the dangers of unlimited satellites on astronomy. They’re trying to address satellite constellations’ impact on astronomy. They’re making efforts to coordinate solutions so both satellites and observational astronomy can continue developing without harmful interference.

    A reminder of what we’re losing when satellites harm astronomy

    One of ESO’s studies estimated that in the future, up to 100 satellites could be visible to the unaided eye during twilight. Imagine how that will change your own view of the night sky. Then imagine if your profession depended upon seeing what is beyond the satellites. How will we learn about the universe or detect potential threats to Earth?

    The IAU created the Dark and Quiet Skies Working Group. As Debra Elmegreen, IAU President, summed up:

    “Interference of our view of the sky caused by ground-based artificial lights, optical and infrared trails of satellite constellations and radio transmission on the ground and in space is an existential threat to astronomical observations. Viewing the night sky has been culturally important throughout humanity’s history, and dark skies are important for wildlife as well.”

    Science papers:
    Astronomy & Astrophysics
    Astronomy and Astrophysics 2020
    Astronomy & Astrophysics 2021
    Air & Space Law 2021
    See the science papers for instructive material.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 8:29 pm on November 1, 2021 Permalink | Reply
    Tags: "How plants survive in the Atacama", , , , , , , , Only the most resilient plant life can cling on among the water-parched rocks and sand., Phylogenomics, Some Atacama plants are closely related to staple crops including grains; legumes and potatoes., , The European Southern Observatory, The international team of researchers has identified the smoking gun: key genes that have helped Atacama’s hardy shrubs adapt to their desiccated homelands., The research area is home to a surprising variety of plant species including grasses; annuals and perennial shrubs., The scientists sequenced the genes expressed in the 32 dominant plant species of the region as well as the genomes of the microbes living in the Atacama soil .   

    From COSMOS (AU) : “How plants survive in the Atacama” 

    Cosmos Magazine bloc

    From COSMOS (AU)

    2 November 2021
    Amalyah Hart

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    The Atacama Desert in northern Chile, one of the driest and harshest environments on Earth. Credit: Melissa Aguilar.

    In the harsh, arid conditions of Chile’s vast Atacama Desert – the driest non-polar desert on the planet – only the most resilient plant life can cling on among the water-parched rocks and sand.

    How these plants came to thrive in such a hostile place is of particular interest to scientists hoping to understand how plant life might adapt to changing ecosystems in a warming world. Now, in a new study published today in PNAS, an international team of researchers has identified the smoking gun: key genes that have helped Atacama’s hardy shrubs adapt to their desiccated homelands.

    The study was an international collaboration between botanists, microbiologists, ecologists, evolutionary biologists and genomic scientists, headed up by a team of Chilean researchers who established a pioneering “natural laboratory” in the Atacama, where they conducted experiments over a decade to understand how the unforgiving landscape was able to nourish life. They measured climate, soil and plant life at 22 sites across varying elevations and types of vegetation.

    The research area is home to a surprising variety of plant species including grasses; annuals and perennial shrubs, all of which are adapted to manage the region’s aridity, altitude, nutrient-poor soil, and the Sun’s harsh radiation.

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    Gabriela Carrasco is identifying, labelling, collecting, and freezing plant samples in the Atacama Desert. These samples then travelled 1600km, kept under dry ice to be processed for RNA extractions in Santiago de Chile. The species Carrasco is collecting here are Jarava frigida and Lupinus oreophilus. Credit: Melissa Aguilar.

    The team brought samples 1000 miles (1600km) to their laboratory, where they sequenced the genes expressed in the 32 dominant plant species of the region as well as the genomes of the microbes living in the Atacama soil that co-exist with the plants.

    Critically, they found some plant species developed growth-promoting bacteria near their roots to optimise their uptake of nitrogen – a nutrient they need in order to grow, but which is notoriously sparse in the Atacama.

    Then, researchers at New York University (US) used an approach called phylogenomics to identify which genes had adapted protein sequences, comparing the 32 Atacama species with 32 genetically similar ‘sister’ species.

    “The goal was to use this evolutionary tree based on genome sequences to identify the changes in amino acid sequences encoded in the genes that support the evolution of the Atacama plant adaptation to desert conditions,” says Gloria Coruzzi, co-author of the study and a professor at NYU’s Department of Biology and Center for Genomics and Systems Biology.

    “This computationally intense genomic analysis involved comparing 1,686,950 protein sequences across more than 70 species,” adds Gil Eshel, who conducted the analysis using the High Performance Computing Cluster at NYU.

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    “Greene,” NYU’s New High-Performance Computing Cluster, is the most powerful supercomputer in the New York metropolitan area, one of the top 10 Most Powerful Supercomputers in Higher Education, and one of the Top 100 Greenest Supercomputers in the world.

    “We used the resulting super-matrix of 8,599,764 amino acids for phylogenomic reconstruction of the evolutionary history of the Atacama species.”

    The studied found 265 candidate genes whose protein sequences were found across multiple Atacama species. Some of these genes adapted the plants’ ability to respond to light and manage photosynthesis, which may have helped them adapt to the extreme irradiation of these high desert plains. Other genes found are involved in the regulation of stress responses and the management of salt intake and detoxification, which could have adapted the plants to Atacama’s high-stress, low-nutrient environment.

    A “genetic goldmine” of precious information

    The research is timely, as this week the world’s leaders attempt to negotiate a global approach to climate change at COP26.

    “Our study of plants in the Atacama Desert is directly relevant to regions around the world that are becoming increasingly arid, with factors such as drought, extreme temperatures, and salt in water and soil posing a significant threat to global food production,” says Rodrigo Gutiérrez, co-author of the study and a professor in the Department of Molecular Genetics and Microbiology at The Pontifical Catholic University of Chile [Pontificia Universidad Católica de Chile] (CL).

    “Most of the plant species we characterised in this research have not been studied before,” he says. “As some Atacama plants are closely related to staple crops including grains; legumes and potatoes, the candidate genes we identified represent a genetic goldmine to engineer more resilient crops, a necessity given the increased desertification of our planet.”

    The Atacama is the home site for the astronomical assets of The European Southern Observatory [Observatoire européen austral][Europäische Südsternwarte](EU)(CL).

    Paranal Observatory pictured with Cerro Paranal in the background. The mountain is home to one of the most advanced ground-based telescopes in the world, the VLT. The VLT telescope consists of four unit telescopes with mirrors measuring 8.2 meters in diameter and work together with four smaller auxiliary telescopes to make interferometric observations. Each of the 8.2m diameter Unit Telescopes can also be used individually. With one such telescope, images of celestial objects as faint as magnitude 30 can be obtained in a one-hour exposure. This corresponds to seeing objects that are four billion (four thousand million) times fainter than what can be seen with the unaided eye.

    European Southern Observatory(EU) , Very Large Telescope at Cerro Paranal in the Atacama Desert •ANTU (UT1; The Sun ) •KUEYEN (UT2; The Moon ) •MELIPAL (UT3; The Southern Cross ), and •YEPUN (UT4; Venus – as evening star). Elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.


    European Southern Observatory(EU) La Silla Observatory 600 km north of Santiago de Chile at an altitude of 2400 metres.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

     
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