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  • richardmitnick 9:34 am on May 11, 2021 Permalink | Reply
    Tags: "Ocean Sensors Record Rare Triple Tsunami near New Zealand", A fault rupture-specifically the vertical thrust produced by a converging subduction plate boundary can be a recipe for a tsunami., A new suite of DART buoys in the South Pacific Ocean spotted waves set in motion by three tsunamigenic earthquakes that occurred within hours of one another., , Despite the dangers of tsunamis some subduction plate boundaries still remain relatively poorly monitored. One example is the Kermadec Trench north of New Zealand., , Eos, In tsunami-prone regions an earthquake is a cue to head to higher ground., The buoys currently in the water are already collecting data and on 5 March they spotted something rare: a triple tsunami., The data DART buoys collect will be disseminated to countries like Chile and the United States that also border the Pacific Ocean and therefore could experience tsunamis from a distant source., Today over 60 DART buoys stand sentry around the world’s oceans.   

    From Eos: “Ocean Sensors Record Rare Triple Tsunami near New Zealand” 

    From AGU
    Eos news bloc

    From Eos

    29 April 2021
    Katherine Kornei

    A new suite of DART buoys in the South Pacific Ocean spotted waves set in motion by three tsunamigenic earthquakes that occurred within hours of one another.

    1
    Ocean sensors recently installed near New Zealand watch for tsunamis. Credit: NIWA-National Institute of Water and Atmospheric Research Climate (NZ).

    In tsunami-prone regions an earthquake is a cue to head to higher ground. But deadly waves can still be on the way if a temblor is felt only weakly—or not at all. Now, researchers working in the southwestern Pacific Ocean have deployed a new suite of ocean-based sensors to detect tsunamis directly. And earlier this year, the instruments spotted a rare triple tsunami caused by three tsunamigenic earthquakes that struck within hours of one another.

    Measure the Wave

    A fault rupture-specifically the vertical thrust produced by a converging subduction plate boundary can be a recipe for a tsunami. But inferring a tsunami’s severity using data from land-based seismometers—before the waves roll ashore—is fraught with uncertainty. That’s why instruments that measure tsunamis directly—tsunameters—are key, said Bill Fry, a seismologist at GNS Science in Wellington, New Zealand, and a member of the New Zealand Tsunami Experts Panel. “Rather than using the earthquake as a proxy, we’re actually measuring the tsunami wave.”

    Tsunameters come in many different forms: Coastal sea level gauges measure changes in water level near shorelines. Cables snaking across the seafloor detect variations in pressure caused by passing tsunamis. Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys record changes in sea surface height.

    DART buoys in particular have many advantages, said Fry. They’re cheaper to deploy than seafloor cables, and they’re not as influenced by nearshore wave effects as coastal sea level gauges are. If they’re placed near the source of an earthquake—such as above an ocean trench—they can also provide advance warning of incoming tsunamis.

    The first DART buoy was deployed in 2000, and five others, all moored in the Pacific Ocean, were added by the end of 2001. Three years later, an official network of the tsunameters was established in response to the deadly tsunami that followed the Sumatra–Andaman earthquake on 26 December 2004. Today over 60 DART buoys stand sentry around the world’s oceans.

    “They’re fascinating things,” said Jose Borrero, a coastal and tsunami scientist at eCoast Marine Consulting and Research in Raglan, New Zealand, and a member of the Tsunami Experts Panel. A DART buoy is composed of a bottom pressure recorder on the seafloor and a surface buoy for transmitting data via satellites, and it can detect minuscule changes in sea surface height. “It can distinguish millimeters of water level fluctuation,” said Borrero.

    Filling in the Gaps

    Despite the dangers of tsunamis some subduction plate boundaries still remain relatively poorly monitored. One example is the Kermadec Trench north of New Zealand. This subduction zone is particularly likely to spawn earthquakes, said Stephen P. Hicks, a seismologist at Imperial College London, because its tectonic plates are converging rapidly, at roughly 7 centimeters per year. “That’s one of the fastest plate boundaries on Earth,” said Hicks.

    The Kermadec Trench, and others nearby, could send tsunamis rolling up on the northern coasts of New Zealand. Armed with that knowledge, the government of New Zealand decided to add 12 new DART buoys to the southwestern Pacific. In December 2019, researchers working aboard the R/V Tangaroa deployed the first four off the eastern coast of New Zealand. The bright yellow buoys, emblazoned with “New Zealand Tsunami Detection,” were joined within a year by four others. By the end of 2021, four more will be installed. Altogether, they’ll monitor the active Hikurangi, Kermadec, Tonga, and New Hebrides trenches.

    Three Earthquakes, Three Tsunamis

    The buoys currently in the water are already collecting data and on 5 March they spotted something rare: a triple tsunami. That day, three separate earthquakes, all greater than magnitude 7, struck near New Zealand. They occurred in rapid succession—at 2:27 a.m., 6:41 a.m., and 8:28 a.m. local time—within 1,000 kilometers of one another. Each launched its own tsunami, and the new DART buoys detected the waves.

    These three overlapping events made for a great test of the new tsunameter network, said Borrero. “Any sort of response system is hard-pressed to deal with that.”

    The new data make it possible to more rapidly estimate potential tsunami impacts in the southwestern Pacific. Observations on 5 March of the waves set in motion by the third earthquake, the largest, at M8.1, allowed researchers to more accurately measure the maximum wave amplitude and better estimate the duration of the tsunami threat to New Zealand’s shorelines. In particular, officials used the measurements to conclude that dangerous waves were no longer likely more than 4 hours earlier than would have been possible previously.

    “Pre-DART, cancellation decisions would have been based on coastal tide gauges,” Fry told Eos. “Many of New Zealand’s tidal gauges are in harbors that can trap energy for hours to days after tsunami waves arrive.”

    These new DART buoys will protect more than just the southwestern Pacific, said Borrero. The data they collect will be disseminated to countries like Chile and the United States that also border the Pacific Ocean and therefore could experience tsunamis from a distant source. “They give us the warning we need, but then [they also feed] into the global network,” said Borrero.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 8:16 pm on May 5, 2021 Permalink | Reply
    Tags: "Taking Stock of Cosmic Rays in the Solar System", Eos   

    From Eos : “Taking Stock of Cosmic Rays in the Solar System” 

    From AGU
    Eos news bloc

    From Eos

    5.5.21
    Jure Japelj

    1
    High-energy particles, also known as cosmic rays, permeate the solar system. Credit:European Space Agency [[Agence spatiale européenn] [Europäische Weltraumorganisation] (EU)

    Scientists hope to find traces of life in exoplanet atmospheres by looking for telltale patterns in an atmosphere’s chemical composition. Those patterns, however, could be altered by cosmic rays. As these energetic charged particles smash into planetary atmospheres at reasonable fractions of the speed of light, they create cascades of secondary particles and radiation that alter atmospheric chemistry. At the extreme, the invisible particles shape a planet’s capacity to host life.

    Cosmic rays’ behavior and impact are poorly understood even in our own solar system, let alone around another star. A team of researchers recently investigated the history of cosmic rays’ barrage on Earth. In a recent paper published in MNRAS, the team showed how the production and transport of cosmic rays in the solar system have changed throughout the Sun’s lifetime. The insight may help facilitate the search for life using atmospheric signals.

    Planets encounter cosmic rays mostly from two distinct sources. One source is the planet’s star, which produces stellar cosmic rays: Stars spew out high-energy particles, primarily protons and the nuclei of helium atoms, through the flares and coronal mass ejections that also feed stellar winds. (Although they come from the same source, a stellar cosmic ray has a million times the energy of a stellar wind particle and is much rarer.) A second, more constant source of cosmic rays is the Milky Way itself, which produces galactic cosmic rays: These particles arise from the remnants of supernova explosions and swarm all over the galaxy.

    “The shape and irregularities of the solar magnetic field determine how particles travel in the solar system,” said Donna Rodgers-Lee, lead author of the study and postdoctoral researcher at the University of Dublin. Solar particles are shoved, pushed, and thrown around by magnetic fields as they move away from the Sun. Galactic particles, on the other hand, need to overcome the push of the solar wind as they move in proximity to the Sun. An increase in stellar cosmic rays usually sweeps away incoming galactic cosmic rays, which are then observed to decrease during that time.

    Modeling a Young Sun

    The younger Sun was more magnetically active and interacted differently with both types of cosmic rays. It used to produce more particles, and its solar wind extended farther into space, which changed the relative contribution of solar and galactic cosmic rays on planets in the solar system. “The fluxes at the position of Earth are anticorrelated. Stellar cosmic rays’ flux was larger when the Sun was younger, and galactic cosmic rays’ flux was lower,” said Rodgers-Lee.

    Federico Fraschetti, a visiting scientist at the Harvard-Smithsonian Center for Astrophysics and senior scientist at the University of Arizona (US), welcomes studies like this one. “Knowing the absolute flux of energetic particles from the Sun at a given energy and how it relates with the total energy released in coronal flares will be very valuable,” he said. Fraschetti was not involved in the research.

    However, Fraschetti pointed out, the team used a simplified model to calculate the transport of particles through the solar magnetic field—a more comprehensive model that includes the solar wind’s natural eddies and turbulence might lead to additional surprises, especially for the very energetic particles.

    Cosmic Weather Around Other Stars

    Although the solar system is the principal arena for studying cosmic rays, findings aren’t directly applicable to other stars. Production of cosmic rays varies from star to star, as does stellar rotation and the consequent patterns of stellar magnetic fields. The present study addressed those variables by simulating the Sun’s evolution, but the options for study are far from exhausted.

    Rodgers-Lee and her team will use their findings to study a sample of exoplanets whose stars have well-measured stellar winds. With the addition of chemical models describing chemical processes in an atmosphere, they believe science will eventually get a grip on the energetic particles in other planetary systems.

    Observations of exoplanet atmospheres have become common in recent years. Nevertheless, Rodgers-Lee can’t wait for the game-changing data from the upcoming James Webb Space Telescope (JWST).

    “JWST will constrain the chemical abundances in the atmospheres of different types of planets around different stars,” she said. “The level of detail will open so many new options.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 10:23 am on April 30, 2021 Permalink | Reply
    Tags: "Imagining What a Metal Volcano Would Look Like", , , , Eos, Ferrovolcanism, ,   

    From Eos: “Imagining What a Metal Volcano Would Look Like” 

    From AGU
    Eos news bloc

    From Eos

    21 April 2021
    Kimberly M. S. Cartier

    1
    Researchers explored what happens when silicate lava and metallic lava mix—or, as it turned out, don’t. Credit: Soldati et al., 2021.

    In 2018, designs for NASA’s Psyche mission to explore the metal asteroid of the same name were being finalized, awaiting approval to be built in a facility in California.

    Meanwhile, across the country, Arianna Soldati was conducting large-scale experiments that involved melting metal-rich basaltic rocks in a furnace, pouring the lava out, and studying how it flowed.

    “During our last pour of the day, I saw this metal come out and I made the connection,” said Soldati, a volcanologist at North Carolina State University (US) at Raleigh. Asteroid Psyche, thought to be a shard of a failed planet’s metallic core, was likely partially molten at one point.

    “To be honest, I didn’t set out saying, ‘Oh, I’m going to study ferrovolcanism. Let me design an experiment to do that.’ It was more opportunistic than that,” Soldati said. That summer, “the Psyche mission…was definitely fresh on my mind.” What would those flows of molten metal have looked like, Soldati wondered, and what features would they have left behind for us to study?

    “We’ve never seen a ferrovolcanic eruption. We’re not even sure if there is one,” Soldati said. “We’re trying to imagine what something that we’re not even sure exists could look like.”

    From Out of the Crucible

    “Ferrovolcanism is a very recent term—it’s only been around for a few years,” and it refers to volcanism that occurs on a metallic body, Soldati explained. The magma that erupts could be entirely metallic (type I in Soldati’s classification) or some combination of rock and metal (type II).

    The first scenario describes what could have taken place on a mostly metallic asteroid like Psyche, but the second scenario might not be unknown on Earth: There’s an open debate among scientists whether the large iron deposit near El Laco volcano in Chile was the result of ferrovolcanism.

    Soldati and her colleagues tested a ferrovolcanism scenario involving both silicate rock and metal. Using one of the furnaces at the Lava Project at Syracuse University in New York, the team melted metal-rich basaltic rock in a silicon carbide crucible. Under heat, the crucible degraded and released carbon which combined with oxygen to form carbon monoxide. The carbon monoxide then chemically reacted with the basaltic melt and separated it into a silicate melt and a denser metallic melt. When the crucible was poured out, the silicate melt flowed first, and the metallic one followed (see video below).


    Ferrovolcanism flow experiment.

    The scientists went into the experiment with few expectations. “There have been no previous experiments that we’re aware of with two materials that are so different and trying to get them to flow together,” Soldati said. “We weren’t sure what would happen.”

    They found that the metallic flow was about 3 times denser and about 100 times less viscous and traveled about 10 times faster than the silicate flow at the same temperature—all in line with fluid dynamics theories. “But it was surprising how independent the two flows remained,” Soldati said. “The silicate flow started earlier, and then the metallic one followed, but it went underneath the rock flow and did its own thing. There was not a lot of interaction between the two. They remained fairly sharply separated.”

    When the metallic flow reached the front edge of the rock flow, it burst out and started flowing freely. “It allowed us to study not only type II but also type I,” Soldati said. “For every experiment, we could get out information on two different types of ferrovolcanism.” On its own, the purely metallic flow was very turbulent: Thin streams separated and braided themselves together like a river delta, and ribbons and beads of metal broke off from the flow completely, only to be subsumed into the silicate flow. The results were published in March in Nature Communications.

    2
    Silicate lava (black) and metallic lava (silver) remained largely separate as they flowed from the lava furnace. Denser and faster flowing metallic lava traveled underneath slower moving and less dense silicate lava and remained unmixed as both cooled. Credit: Soldati et al., 2021.

    “The experiments demonstrate a mingling but inefficient mixing between silicate and metallic lavas,” explained planetary volcanologist Pranabendu Moitra. “It provides better insights to the flow behavior and morphology of dense, less viscous and turbulent metallic melts,” which behave very differently than silicate flow. Moitra, at the University of Arizona in Tucson, was not involved with the study.

    Imagining the Unknown

    If a ferrovolcano did exist, what would it look like? This experiment could help give a very basic idea. “Metal, because it is very dense and [of] very low viscosity, forms low-relief topography,” Soldati said. “There’s not going to be a tall ferrovolcano. There’s not going to be a Mount Fuji made of metal. The topography is going to be very shallow, with flows that will extend very far away from the vents. And these flows are probably going to be extremely braided, with many tiny channels.”

    “These are gorgeous experiments! I would have loved to see them happen,” said Lindy Elkins-Tanton, a planetary scientist at Arizona State University in Tempe and principal investigator of the Psyche mission who was not involved with this research. But as this particular experiment involved both rock and metal, “I’m not confident they apply to Psyche; we can’t think of a circumstance when metal—really, it would likely be sulfide, FeS—and silicate magma would be erupting at the same time. Still, we’ll look for those textures.”

    Soldati and her team will be going back to the Syracuse Lava Project later this year to conduct more experiments, including some that will explore purely metallic lava flows with different types of metals and under different flow conditions. “The experimental results could further validate lava flow models,” Moitra said. “It will be interesting to explore the effects of various experimental parameters such as the slope, and the lava and ambient temperature, etc., on the speed and morphology of metallic lava flows as compared to the silicate ones.”

    Experiments like these, said Soldati, offer volcanologists the rare opportunity to come up with a theory first and then go out and see whether they were right or wrong. “When the paper was in review, a comment from one of the reviewers corrected the spelling of the title, changing it from ‘Imagining Ferrovolcanism’ to ‘Imaging Ferrovolcanism.’ But the point of the study was not to image something. It was really to imagine what a certain landscape could look like, which, I think, is still an important part of science, especially in volcanology, which is such an observation-based scientific field.”

    “We have to put in the imagination work first so we can compare with our observations later.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 12:54 pm on April 27, 2021 Permalink | Reply
    Tags: "1.3 Million Pairs of Stars Surround the Sun", , , , , Eos   

    From Eos: “1.3 Million Pairs of Stars Surround the Sun” 

    From AGU
    Eos news bloc

    From Eos

    31 March 2021 [Just now in social media.]
    Kimberly M. S. Cartier

    1
    The Hubble Space Telescope captured this view of Milky Way stars in the constellation Sagittarius in 2017. Credit: European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU)/National Aeronautics Space Agency (US).

    Data from a galaxy-mapping satellite have revealed that the solar neighborhood is teeming with stars that travel in pairs. Using data from the Gaia mission, researchers have identified 1.3 million binary pairs (2.6 million stars) within about 3,200 light-years of the Sun on the basis of the stars’ positions and trajectories. From this discovery, researchers learned that roughly half of all Sun-like stars are gravitationally bound to a companion star and that the paired-up stars prefer to be separated by about the distance between the Sun and Pluto.

    Previous catalogs had identified roughly 200 binary pairs through independent measurements and about 100,000 unconfirmed candidates. Not only is this 3D atlas a significant leap forward in binary star identification, but it also will help astronomers better understand how stars form and dynamically evolve, pinpoint the ages of some stars and their planets, and study how stellar companions might affect the formation of planetary systems.

    “Just like single stars, many binaries have planets around them,” said Kareem El-Badry, an astronomy doctoral student at the University of California, Berkeley (US), and lead researcher on the catalog. “From studying the population demographics of binaries in this catalog—such as their distributions in periods, eccentricities, separations, masses, things like that—we learn details about how the star formation process happens, which is intimately related to how planets form.”

    One Star, Two Star, Close Star, Far Star

    When it comes to objects in space, the distance to that object is one of the most challenging, and most important, measurements to take. For example, a star that is very close to Earth but very dim could look the same as a star that is very bright and very far away. But knowing whether it’s one or the other is very critical for understanding how that star, and any planets it may host, formed and evolved.

    Stellar parallax is the most precise way to measure the distance from Earth to a star (see video at right), and it can be done only for stars that are close enough to Earth for their movement to be seen. About 30 years ago, the European Space Agency’s (ESA) Hipparcos space astrometry mission used this method to measure the distances to roughly 2.5 million stars in the Milky Way, and astronomers have relied on those data as starting points to calculating distances to objects farther away.

    In the past few years, however, ESA’s Gaia mission has been picking up the torch.

    Gaia is systematically measuring the positions, distances, and motions of nearly 1 billion stars in our galaxy and beyond, creating an unprecedented 3D map of Earth’s cosmological home.

    El-Badry’s team used these data to search for nearby binary stars, that is, two stars that formed at the same time from the same cloud of gas and dust and gravitationally interact with each other. In Gaia data, binary stars would appear to be the same distance from Earth, move through the galaxy with the same directions and speeds, and be separated from each other by no more than about 3 light-years. (Beyond that separation, gravity isn’t strong enough to keep the pair together.) The researchers also evaluated the chances that a pair had one star that was a random background star, that a pair might have a third star, and that pairs might be part of a cluster of stars, and they filtered out pairs that had a high likelihood of any of those.

    Out of about 65 million stars and about 2 quadrillion possible pairings within about 3,200 light-years of the Sun, the team identified 1.3 million pairs of stars with a high likelihood of being gravitationally bound (see video below). Of those pairs, nearly 900,000 are pairs of hydrogen-burning stars like the Sun, about 16,000 have one hydrogen-burning star and one white dwarf, and nearly 1,400 have two white dwarfs. The results, which were published in MNRAS in February, support the long-held theory that most Sun-like stars have a binary companion and that binary companions are typically separated by 30–50 times the Earth-Sun distance (an astronomical unit, or AU), roughly the distance from the Sun to Pluto.


    Stars aligned: An atlas of binary stars.

    This study showed that “for stars about the mass of the Sun, something like 25% of them have a companion beyond about 30 AU,” El-Badry said. “And then from other work, we think that another 25% have a companion closer than 30 AU. So when you add it up, about half of Sun-like stars have a stellar companion.”

    Twins, White Dwarfs, and Planets

    “Another thing we can look at is what is the distribution of mass ratios in the systems. Do the stars like to be about the same mass or very different?” El-Badry explained. “One of the most surprising and exciting results that’s come out of [this work] is that there is an unexpected excess population of binaries where the two stars are almost exactly the same mass. We call them identical twins.” This result is surprising because at such wide separations, the stars should form independently of each other, and so their mass ratios should be more randomized. The team suspects that twin stars were actually born much closer together and drifted apart over the years. These dynamics could influence the stability of a hypothetical planetary system, the researchers say.

    2
    Around half of all Sun-like stars are one of a pair. Above, a collage of some of these binary star pairs as seen by the Gaia spacecraft. Credit: ESA/Gaia/ESA DPAC Consortium – Gaia – Cosmos [Data Processing and Analysis Consortium] (EU).

    Moreover, this catalog could help astronomers determine the ages of hydrogen-burning stars, which is also very difficult to do. “It’s relatively easy to measure age of a white dwarf, at least compared to how hard it is to measure the age of a normal star,” El-Badry said. For pairs that have a hydrogen-burning star and a white dwarf, the white dwarf’s age can be assumed for all components in the system, including exoplanets.

    That’s exactly how the team, led by astronomer David Martin, used this catalog to study planet candidate TOI-1259Ab [https://arxiv.org/abs/2101.02707], first discovered by the Transiting Exoplanet Survey Satellite (TESS).

    NASA/MIT Tess

    NASA/MIT Tess in the building.


    NASA/MIT TESS replaced Kepler in search for exoplanets.

    TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center.

    Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Center for Astrophysics – Harvard and Smithsonian in Cambridge; MIT Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore.

    “The TESS satellite has discovered thousands of candidate transiting exoplanets,” Martin said. “What we did was cross match the two catalogs, restricting the Gaia binaries to special ones containing at least one white dwarf. From that, we came up with this candidate, TOI-1259, which has a planet transiting a main sequence star and a white dwarf companion. The fact that it has a white dwarf companion came from [El-Badry’s] catalog. Such systems are rare and can tell us a lot about how stellar and planetary systems evolve.” With the white dwarf’s age calculated to be 4.1 billion years, TOI-1259Ab has one of the oldest-known ages for an exoplanet. Martin, at The Ohio State University (US), was not involved with the creation of the binary star catalog.

    Martin plans to keep working with the new catalog. “Right now, we are working on expanding this work from this first candidate to other similar systems that contain both a planet and a white dwarf,” Martin said. There are at least 300 more of those types of systems in El-Badry’s catalog. “That, of course, is just a targeted use.…Really, if you find any planet transiting any star, you should cross match it with [the] catalog to see if there is any type of stellar companion!”

    El-Badry hopes that other astronomers use these data to help calibrate relationships between a star’s age and its easily measured characteristics like rotation, in addition to studying population-level demographics for these systems. Future releases of Gaia data will increase the precision with which they can calculate the positions and motions of stars, El-Badry said, letting scientists detect binary stars that are very close together and also detect movement caused by an unseen companion, like a black hole.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 12:02 pm on April 27, 2021 Permalink | Reply
    Tags: "A Massive Methane Reservoir Is Lurking Beneath the Sea", , , Eos   

    From Eos: “A Massive Methane Reservoir Is Lurking Beneath the Sea” 

    From AGU
    Eos news bloc

    From Eos

    4.27.21
    Fanni Daniella Szakal
    fanni.szakal@gmail.com

    Scientists have found a methane reservoir below the permafrost seabed of the Laptev Sea—a reservoir that could suddenly release large amounts of the potent greenhouse gas.

    1
    A massive methane reservoir beneath the submarine permafrost of the Laptev Sea has started to leak. Credit: NASA Earth Observatory (US) images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey.

    Methane bubbles regularly reach the surface of the Laptev Sea in the East Siberian Arctic Ocean (ESAO), each of them a small blow to our efforts to mitigate climate change. The source of the methane used to be a mystery, but a joint Swedish-Russian-U.S. investigation recently discovered that an ancient gas reservoir is responsible for the bubbly leaks.

    Methane in the Laptev Sea is stored in reservoirs below the sea’s submarine permafrost or in the form of methane hydrates—solid ice-like structures that trap the gas inside. It is also produced by microbes in the thawing permafrost itself. Not all of these sources are created equal: Whereas microbial methane is released in a slow, gradual process, disintegrating hydrates and reservoirs can lead to sudden, eruptive releases.

    Methane has now started to escape as the Laptev’s submarine permafrost is thawed by the relative warmth of overlying seawater. With an even stronger greenhouse effect than carbon dioxide, methane releases into the atmosphere could substantially amplify global warming.

    “To anticipate how these methane releases will develop over the coming decades or centuries, we need to understand what reservoirs of methane the releases are coming from,” said Örjan Gustafsson, leader of the research group that conducted the investigation.

    1
    This map shows the study area and sampling locations for methane concentrations and isotopes. Credit: Steinbach et al., CC BY 4.0.

    Distinguishing Sources of Methane

    Julia Steinbach, a researcher at Stockholm University [Stockholms universitet](SE) and lead author of the new research, was instrumental in devising the triple-isotope-based method for finding methane sources. Stable isotopes detect the origin of the molecules, and radioactive isotopes help to find their age. Using this novel approach, the team discovered that the source of the methane was an old reservoir, deep below the permafrost. The study was published in the PNAS of the United States of America in March.

    “The big finding was that we really have something that’s coming out from a deep pool,” said Steinbach. As the permafrost thaws, it opens up new pathways that allow methane to pass through.

    According to Gustafsson, this is worrying, as the pool likely contains more methane than is currently in the atmosphere. “There is, unfortunately, a risk that this methane release might increase, so it will eventually have a sizable effect on the climate,” he said.

    The Challenge of Predicting Methane Releases

    Although intrigued by the study, Jennifer Frederick, a geoscientist at DOE’s Sandia National Laboratories (US) not involved in the recent research, warned against trying to inflate its findings. “It is very challenging to be able to be confident that your small area is representative of the larger area,” she said. She is hopeful, however, that with enough of these types of studies, scientists will get to a point where they can make accurate predictions about methane releases.

    Gustafsson also emphasized that the results are applicable only to this specific location. “It is quite plausible that there are other sources—the thawing permafrost or the hydrates that can be the major source of methane in other parts of this enormous system.”

    Even though the study area concerns one of the places on Earth most difficult to reach, the scientists hope to conduct more expeditions to map methane sources in the ESAO. “The permafrost is a closed lid over the seafloor that’s keeping everything in place. And now we have holes in this lid,” said Steinbach. “That means that we really have to keep a close look on it.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 11:33 pm on April 24, 2021 Permalink | Reply
    Tags: , "Auroral dunes", "Charting Satellite Courses in a Crowded Thermosphere", "Cubist Geomorphology: Your Kinship with Picasso Explained", "Ham Radio Forms a Planet-Sized Space Weather Network", , Eos   

    From Eos: “Paying Attention to the ‘Ignorosphere'” 

    From AGU
    Eos news bloc

    From Eos

    22 April 2021
    Heather Goss

    1
    A view of Earth’s thin atmosphere from the International Space Station. Credit: National Aeronautics and Space Administration (US).

    In our May issue of Eos, we are looking up at a region of Earth’s atmosphere, the scientists in these pages argue, that we aren’t looking at quite enough. That region is called geospace, which encompasses the mesosphere and the thermosphere from altitudes of around 45 to 1,000 kilometers.

    In An Observational Gap at the Edge of Space, Martin Mlynczak and colleagues write about how geospace is sensitive to changes in carbon dioxide. Some research has already shown that effects from climate change are changing the density of geospace and thus aerodynamic drag in this “atmospheric borderland” where satellites orbit. Although there are missions observing this region right now, most are past their design lifetimes and have no successors, leaving a looming gap.

    Sean Bruinsma and colleagues go into more detail about the consequences to the ever more populated low Earth orbital paths in Charting Satellite Courses in a Crowded Thermosphere. “Despite progress made over the past couple of decades, large uncertainties still exist in estimates of the solar, magnetospheric, and gravity wave energy input to—and thus in how this energy affects—the thermosphere,” write the authors, who suggest that a geospace-focused study be commissioned in time for the next heliophysics decadal survey.

    Could one solution for the data gap be…ham radio? One group called the Ham Radio Science Citizen Investigation, or HamSCI, is harnessing access to inexpensive, open-source instrumentation along with their passionate, global community to create usable data sets for researchers. The group is particularly focused on the ionosphere, the layer of geospace that reflects radio waves, and how it experiences variability that affects the propagation of those signals. This work may not replace the real-time, continuous observations that space missions can provide, but it is already contributing to research. Read more from Kristina Collins and colleagues in Ham Radio Forms a Planet-Sized Space Weather Network.

    In another wonderful story about nonscientists providing important data to researchers, read about auroral dunes. A group of amateur astronomers in Finland had gathered online to celebrate a new book featuring their photography when one of them saw peculiar green stripes in the sky—3 years to the day since the group had last seen this auroral phenomenon. The club members are now collaborating with researchers to use the observations of the unusual structure of the dunes to study this part of the upper mesosphere where they occur.

    Finally, be sure to take a Braque break. When glaciologist Donovan Dennis told us he wanted to write about Cubist Geomorphology: Your Kinship with Picasso, Explained, we were excited to read his unusual take. He reminds us that “this Cubist example is one of many possible comparing the intellectual endeavors of artists and geoscientists and demonstrates the long-observed belief that both disciplines stand to strongly benefit from each other.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 2:06 pm on April 16, 2021 Permalink | Reply
    Tags: "Making the Universe Blurrier", Another fire threatened Mount Wilson Observatory near Pasadena CA (US), Cerro Paranal- the site of the ESO VLT and other telescopes-remains one of the best observing sites on the planet. Yet it’s not as pristine as it was at the time of its selection in 1990., Climate change could make the telescopes’ observations a little less crisp., Eos, Many observatories are remote- they have limited access- so defending them against forest fires can be very difficult., , Siding Spring Observatory in Australia lost its lodge for visiting astronomers and other structures in 2013 and the country’s Mount Stromlo Observatory lost several major telescopes in 2003., Threats on the Ground-fire on California’s Mount Hamilton burned one residence and damaged others at Lick Observatory.   

    From Eos: “Making the Universe Blurrier” 

    From AGU
    Eos news bloc

    From Eos

    13 April 2021
    Damond Benningfield

    1
    The domes of the Very Large Telescope (CL) and smaller telescopes are reflected in the aftermath of an infrequent rainfall atop Mount Paranal, Chile. Climate change could make the telescopes’ observations a little less crisp. Credit: A. Ghizzi Panizza/ESO, CC BY 4.0

    When the European Southern Observatory (ESO) selected Cerro Paranal, a 2,664-meter mountain in Chile’s Atacama Desert, to host its Very Large Telescope (VLT), it touted the location as “the best continental site known in the world for optical astronomical observations, both in terms of number of clear nights and stability of the atmosphere above.”

    Cerro Paranal remains one of the best observing sites on the planet. Yet it’s not as pristine as it was at the time of its selection in 1990. A study released last September [Nature Astronomy] showed that temperatures have climbed and jet streams are more troublesome making the VLT’s observations of distant stars; galaxies; and exoplanets a tiny bit fuzzier.

    “The main motivation of this study was to raise awareness among the astronomical community that climate change is impacting the quality of observations,” said Faustine Cantalloube, an astrophysicist at Laboratoire d’Astrophysique de Marseille (FR) and lead author of the report.

    “As atmospheric conditions influence the astronomical measurements, it is important to be prepared for any changes in the climate,” agreed Susanne Crewell, a coauthor and a professor of meteorology at the University of Cologne [Universität zu Köln](DE). These preparations are especially relevant as ESO is building the Extremely Large Telescope (ELT), a 39-meter behemoth that will be the largest telescope in the world, on a peak about 20 kilometers from Paranal.

    ELT is expected to be a “workhorse” for decades, said Crewell.

    Astronomers are just beginning to consider how those changes are affecting observations or might affect them in the years ahead. Potential problems include reduced “seeing”—the clarity with which a telescope observes the universe—plus greater risk from forest fires and a need for more power-consuming air-conditioning to keep telescope mirrors cool.

    “Long term, we’re concerned about how climate change will affect the viability of certain observing sites,” such as Paranal and others in Chile, said Travis Rector, an astronomer at the University of Alaska Anchorage and chair of the American Astronomical Society (US) Sustainability Committee. “Will we enjoy the same quality observing conditions many years down the road?”

    Evaluating the VLT as a Test Case.

    Paranal is the first observatory for which scientists have studied that question. Cantalloube’s team compiled more than 3 decades of weather observations made at the site, including temperature, wind speed and direction, and humidity. The study also included a reanalysis of information from two European climate databases that date to 1980.

    The records revealed a temperature increase of 1.5°C over the study period. The change is important because the VLT’s domes are cooled during the day to match the expected ambient temperature at sunset. If the telescope mirrors are warmer than the air temperature, heat waves ripple above them like those above a desert highway on a summer afternoon, blurring the view.

    The VLT’s current cooling system was designed to maintain a temperature no higher than 16°C because when the telescopes were designed, sunset temperatures exceeded that value roughly 10% of the time. In 2020, though, they did so roughly one quarter of the time. As a result, Cantalloube said, air-conditioning capacity, as well as cooling capacity for many telescope instruments, will need to be increased in the future as the temperature continues to rise (perhaps by up to 4°C by the end of the century, according to some models).

    The study also found that changes in the jet stream cause periodic increases in wind shear in the upper troposphere, particularly during El Niño events, creating a blurring effect known as a wind-driven halo. The VLT’s four component 8-meter telescopes are equipped with adaptive optics, which use lasers and deformable mirrors to create and focus an artificial “guide star” in the upper atmosphere, compensating for most of the blurring.

    But turbulence from the wind shear is making it tougher for the system to work. That’s particularly troublesome for efforts to image exoplanets, which require both high resolution and high contrast, the study noted.

    “Monitoring meteorological parameters on site is one way to make the best out of the telescope time thanks to an adapted observing schedule,” said Cantalloube. For example, “some observations are less affected by humidity and some more, so if we know in advance the atmospheric humidity content, we can schedule observing programs accordingly.”

    Cantalloube said her team is continuing to evaluate the Paranal data while expanding its work to study conditions at major observatories in Hawaii, Arizona, and the Canary Islands.

    Threats on the Ground

    Rector notes that climate challenges aren’t limited to the quality of the view, though. “The most obvious threat is forest fires,” he said. “In recent years we’ve seen several major fires come near observatories, especially in California.”

    Last August, for example, a fire on California’s Mount Hamilton burned one residence and damaged others at Lick Observatory and barely missed some of the telescopes.

    A month later, another fire threatened Mount Wilson Observatory, near Pasadena.

    Siding Spring Observatory in Australia lost its lodge for visiting astronomers and other structures in 2013 and the country’s Mount Stromlo Observatory lost several major telescopes in 2003.

    “Many observatories are remote- they have limited access- so defending them against forest fires can be very difficult” Rector said. “They’re the most vivid threat.”

    Proposed Solutions

    One proposed solution to climate change could actually cause more problems for astronomy, Rector said. Some climate scientists have suggested that injecting aerosols into the upper atmosphere could reduce the amount of sunlight reaching the surface, perhaps reversing the warming trend. However, that would also reduce the amount of light from stars and other astronomical objects reaching the surface. “Aerosols are probably best saved as a last-ditch Hail Mary,” Rector said.

    Cantalloube and others said that astronomers also must reduce their own carbon footprint by reducing travel, cutting back their reliance on energy-guzzling supercomputers, and taking other steps. “Technological developments can cope with these subtle effects due to climate change,” Cantalloube said. “I’m more concerned about the way round: How can we make our observatories greener?”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 4:41 pm on April 8, 2021 Permalink | Reply
    Tags: "Relating Seismicity and Volcano Eruptions", , , , Eos, ,   

    From Eos: “Relating Seismicity and Volcano Eruptions” 

    From AGU
    Eos news bloc

    From Eos

    4.7.21
    Ilya Zaliapin

    A global study suggests that volcanic eruption forecasting and detection may be improved by examining earthquake mechanisms and clustering in combination with individual volcano properties.

    1
    Seismicity near Mount Rinjani volcano (white square) at Lombok Island, Indonesia, during July-September 2018, according to the USGS ComCat catalog. Colors represent event timing as indicated in the legend. Moment tensors (beachballs) are shown for the four earthquakes with magnitude above M6. Dashed circle shows the 30 km radius used to associate earthquakes with volcanoes in the study. Currently, over 1 million people live within this circle. The lack of similar historical seismicity in the area, the swarm-like nature of the earthquakes, and a substantial percentage of the non-double-couple components raise concerns that the volcano may be awakening. Credit: Pesicek et al. [2021], Figure 10.

    Earthquakes are known to precede and coincide with volcanic activity, being triggered by multiple mechanisms (such as stress and pore pressure changes) related to the magmatic processes. Thus it might be possible to use seismicity to forecast impending volcanic eruptions and detect ongoing eruptions at remote and submarine locations that may lack permanent close monitoring.

    Pesicek et al. [2021] offer a global quantitative perspective on the problem. They examine 870 volcanoes with confirmed Holocene eruptions (those that happened within the past 11,700 years) in relation to the earthquakes with magnitude equal to or above 4 within 30 kilometers of the vent. The occurrence of such an earthquake by itself does not tell much (only 1 percent of events are followed by an eruption and only 11 percent of eruptions are preceded by earthquakes), but additional properties of volcanos and seismicity may have improved predictive power. In particular, more than half of the examined multiple-event swarms with an increased percentage of non-double-couple earthquake mechanisms preceded eruptions.

    The results suggest that combining individual volcano properties and multiple earthquake statistics may inform and improve multi-disciplinary approaches to probabilistic volcano forecast and detection.

    Science paper:
    Journal of Geophysical Research: Solid Earth

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 4:17 pm on April 5, 2021 Permalink | Reply
    Tags: "Probing the Age of the Oldest Ocean Crust in the Pacific", , , Eos, , , The current GPTS extends from today backward in time down to magnetic anomaly M29 (approximately 157 million years ago)., The geomagnetic polarity time scale (GPTS) is based on the marine magnetic anomalies- the striping pattern of strong and weak magnetic signals recorded by the ocean crust., Tominaga et al. [2021] extend the geomagnetic polarity time scale down to the Mid Jurassic (M44- about 170 million years ago) based on a composite of the Japanese lineation set they published previous   

    From Eos: “Probing the Age of the Oldest Ocean Crust in the Pacific” 

    From AGU
    Eos news bloc

    From Eos

    4.5.21
    Mark J. Dekkers

    1
    Map of magnetic anomaly field intensity in the study area in the Pacific Ocean, with the location of the magnetic anomaly profiles indicated with green lines. Blue colors indicate a positive polarity (normal field) and red colors negative polarity (reverse field); pale (intense) colors indicate weak (strong) magnetic anomaly expression. Credit: Tominaga et al. [2021] [below], Figure 8b.

    The geomagnetic polarity time scale (GPTS) is based on the marine magnetic anomalies- the striping pattern of strong and weak magnetic signals recorded by the ocean crust. Strong signals correspond to normal polarity and weak signals to reverse polarity. Adjacent normal and reverse stripes are numbered, backward in time from C1 (top = today) to C34, of which the normal portion is a long period of normal polarity in the Mid Cretaceous. Older magnetic stripes are referred to as the M-sequence (Mesozoic sequence) starting with M0 below the very long C34 anomaly.

    The current GPTS extends from today backward in time down to magnetic anomaly M29 (approximately 157 million years ago). Older oceanic crust is rare and typically has subdued magnetic anomaly patterns that are difficult to correlate. Thus, pre-M29 time scales remain controversial because the marine magnetic anomaly data is of rather poor quality. This complicates analysis of important features of the geomagnetic field: the reversal frequency and the expression of the Mesozoic dipole low (also termed Jurassic Quiet Zone).

    Tominaga et al. [2021] extend the geomagnetic polarity time scale down to the Mid Jurassic (M44- about 170 million years ago) based on a composite of the Japanese lineation set they published previously, and a new, highly detailed, multiscale magnetic anomaly profile of the Hawaiian lineation set, both from the western Pacific Ocean.

    The weak anomaly portion M41-M39 is best expressed in the Japanese profile and argued to represent the onset and maximum expression of the Mesozoic dipole low or the core of the Jurassic Quiet Zone, an important long-lasting low-intensity feature of the geomagnetic field. From the midwater reference profile, the Jurassic reversal frequency in the M29-M44 time span (157-170 million years ago) appears to have been about 19 reversals per million years, i.e. extraordinarily high, and double the previous estimates for that period.

    Citation: Tominaga, M., Tivey, M. A., & Sager, W. W. [2021] Journal of Geophysical Research: Solid Earth.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 9:25 am on April 2, 2021 Permalink | Reply
    Tags: "The Difficulty of Defining the Anthropocene", , , Eos, One person’s Anthropocene is not another person’s Anthropocene is not another person’s Anthropocene and if the difference between the meaning stretches too widely then there’s always a possibi   

    From Eos : “The Difficulty of Defining the Anthropocene” 

    From AGU
    Eos news bloc

    From Eos

    29 March 2021
    Alka Tripathy-Lang

    Humans may be in a new geologic epoch—the Anthropocene—but different groups define its start at varied times. When should the Anthropocene have begun?

    1
    A plastiglomerate from Kamilo Beach in Hawaii is displayed at Museon in The Hague, Netherlands. Plastiglomerates are just one of several examples of the collision between geological processes and industrialization. Credit: Aaikevanoord/Wikimedia, CC BY-SA 4.0.

    At the bottom of Crawford Lake in Ontario, Canada, pristine layers of fine sediment accumulate year after year. Because the lake is small and tranquil, bottom currents do not jostle the sediment, nor does lacustrine life chew through the laminations. Each layer, called a varve, represents an annual record of any hubbub (or lack thereof) affecting the lake waters, going back almost 1,000 years.

    In sediment cores carefully extracted from the lake, scientists can see traces of Iroquois horticultural activity dating back at least 750 years, and evidence of invading European settlers in the mid-19th century, said University of Leicester paleobiologist Jan Zalasiewicz. In the topmost layers curated by the lake, scientists can systematically search for signs of plutonium, cesium, radiocarbon, fly ash, and microplastics. Such signatures might indicate the beginning of the Anthropocene, a proposed addition to the geologic timescale governed by the International Commission on Stratigraphy (ICS).

    The idea of the Anthropocene, introduced by late atmospheric scientist Paul Crutzen at a conference in Mexico in 2000, expresses humanity’s profound impact on the planet and signals an end to the Holocene epoch, which began 11,700 years ago. Because the Anthropocene results from the intersection of the natural world and human society, the term has been adopted by numerous scholarly communities including archaeology, philosophy, and even international law.

    In a recent paper, Zalasiewicz [Earth’s Future], chair of the ICS Subcommission on Quaternary Stratigraphy (SQS), and a corps of colleagues in fields ranging from history to soil science explored what the Anthropocene means to the various groups who use the term. “One person’s Anthropocene is not another person’s Anthropocene” said Zalasiewicz, “and if the difference between the meaning stretches too widely then there’s always a possibility of confusion.”

    Identifying Ground Zero

    To define a new unit of geologic time, scientists must find a synchronous, globally identifiable signal. For example, at the end of the Cretaceous, an asteroid crashed into what is now the Gulf of Mexico’s Yucatan Peninsula, decimating nonavian dinosaurs and countless other species. The extraterrestrial impactor vaulted gas and ash into the atmosphere and left behind a globally distributed, iridium-rich layer that today formally defines the Cretaceous–Paleogene boundary.

    However, finding the base of the Anthropocene has been “a long and fiddly process,” said Zalasiewicz, in part because the SQS Anthropocene Working Group originally focused on a red herring: the beginning of the Industrial Revolution, around 1800. More recently, the group has found promise in the Great Acceleration of the 1950s, defined by a surge in numerous measures of human activity. The newest veneers of the geologic record contain various human-sourced signals like radionuclides produced from aboveground nuclear tests, plastics intermingled with sediment, and fine particles of coal combustion called fly ash. Although not traditionally geological, these features can be treated as geological ingredients of strata, said Zalasiewicz.

    To find the best possible candidate for the fabled golden spike that will serve as the type locality should the Anthropocene become formally defined, “there is quite a long initial sift,” explained Zalasiewicz. The SQS group is studying a dozen or so candidates, including coral skeletons, Antarctic ice cores, peat bogs, and, of course, lake sediments. Layer by layer, the search for plutonium content, radiocarbon signals, and other signatures will form the bricks for constructing descriptions of each candidate. The most robust site with the strongest foundation of data will then be recommended as the type locality of the shift from the Holocene to the Anthropocene, said Zalasiewicz.

    Carrying the Burden

    Some geologists argue that the Anthropocene should remain an informal term, said Dipesh Chakrabarty, a historian at the University of Chicago who was not involved in the recent review. For example, hominin management of fire marks the first time that a biological species had more energy available than it could produce on its own. Alternatively, the transition from hunting and gathering to agrarian food production denotes a striking change in societal litter.

    Besides these examples, some scholars wish to “connect the beginning of [the Anthropocene] to European expansion and [the] death of hundreds of thousands of people in Latin America,” Chakrabarty said, because “they want to find a political origin.” Proponents of these political definitions suggest various portmanteaus that reflect colonialism’s role in industrialization, including terms like Capitalocene, Econocene, or even Plantationocene. Anthropo- implies that all humans have been equally responsible for greenhouse gas emissions, but “privileged people emit more emissions, [and] the bad impact of climate change will fall unevenly in the world,” explained Chakrabarty, possibly making the term misleading, depending on the context.

    In addition, nongeologists may not recognize that “the name of a geological time period does not have to account for why that period came about,” Chakrabarty said. “That term ‘Anthropocene’ doesn’t have to carry the burden of pointing to [its] causal factors.”

    Indeed, Zalasiewicz and his colleagues, several of whom are nongeologists, want to “encourage the interchange between different disciplines while making the clarity of the communication as precise as possible.” They suggest that should the Anthropocene become a formal unit of geologic time, other groups could use alternate terms, similar to how different communities use the terms Pleistocene and Paleolithic for a roughly contemporaneous period of time. (The former denotes a geological time span corresponding to the most recent episode of glaciations, whereas the latter denotes an anthropological time span corresponding to the human use of stone tools.)

    “If [the Anthropocene] does get ratified, said Chakrabarty, “that would be great, but for somebody who is trying to think through human history…I’m deeply interested in the predicament.” That predicament is the one recorded by threatened corals, warming ice, and the sediments of Lake Crawford, laden with evidence of humanity’s excesses.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
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