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  • richardmitnick 10:41 am on July 17, 2019 Permalink | Reply
    Tags: , , , , , Eos, ,   

    From Eos: “The Cassini Mission May Be Over, but New Discoveries Abound” 

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    From Eos

    Sarah Derouin

    NASA/ESA/ASI Cassini-Huygens Spacecraft

    New analysis of high-resolution images shows ring textures and disruptions within Saturn’s rings in unprecedented detail.

    The embedded moon Daphnis creates three waves in Saturn’s rings in this image taken by the spacecraft Cassini during its grand finale. Credit: NASA/JPL-Caltech /Space Science Institute
    After more than a decade observing Saturn, Cassini completed its mission in style—a grand finale sent the spacecraft on almost 2 dozen dives between the planet and the rings before it took its final descent into Saturn’s atmosphere.

    During these ring-grazing trips during summer 2017, Cassini collected high spatial resolution images and spectral and temperature scans of the rings. Years after its crash, researchers are still working with the piles of data Cassini collected, making new discoveries about the ringed planet.

    In a new paper in Science, researchers dove into these high-resolution data, and their synthesis revealed new features inside the rings that hadn’t been seen before. They found sculpted areas within the rings—including banded textures and disturbances from embedded bodies—that can be used to help theorists narrow in on how Saturn and its rings may have formed.

    Ring Disruptions

    During the grand finale, Cassini took high-resolution images of all the rings, from the ring closest to the planet (ring A) to the F ring, one of the most distant. The images are the highest-fidelity images ever to be taken of the rings, and they revealed some surprises to the research team.

    “We found a number of things that are new—a number of structures that we’d never been close enough to see before,” says Matthew Tiscareno, a senior research scientist at the SETI Institute in Mountain View, Calif., and lead author of the paper.

    The team explored disturbances within the rings related to moons or smaller moonlike debris embedded in the rings. The moon Daphnis, for example, leaves a wide trail of disruption in its wake, including a wide gap in the ring and trailing waves of debris.

    These waves, Tiscareno explains, are created by the rings moving at different speeds: The rings orbiting closer to Saturn move at a faster speed than those farther from the planet. This process creates a sheer flow, and “on the outward edge, the ring part, the ring material is falling behind Daphnis and its orbit,” he says.

    This propeller, informally called Bleriot, formed within Saturn’s rings. Propellers are caused by a central moonlet that alters the ring as it orbits around the planet. Credit: NASA/JPL-Caltech/Space Science Institute

    But it’s not just big moons like Daphnis that disrupt the rings. Smaller objects are trying their best to create ring gaps as well, but with less success. “These are objects that are 10 times smaller, which means they’re a thousand times less massive,” says Tiscareno.

    Instead of forming a gap, Tiscareno says these objects form a propeller-shaped disturbance. The swirled structure forms briefly but doesn’t stick around long enough to create a true gap in the ring.

    The researchers knew the propellers existed, so they asked Cassini to perform some targeted flybys to get a closer look.

    “The details of that [propeller] structure [are] telling us exactly how big the moons are at the center of the propeller…about a kilometer across,” says Tiscareno, adding that at that size, it’s not possible to see the actual moon with these image resolutions.

    Ring Textures

    Cassini’s instruments also revealed new details on textures within the rings. “We knew that there were textures before, but we had not seen them as comprehensively,” says Tiscareno. The team noted that the ring textures ranged from strawlike clumps to feathery regions, with sharp edges on their borders.

    One idea for the different textures within the rings is a changing particle composition, says Douglas Hamilton, an astronomer at the University of Maryland who was not involved with the paper. For example, one part of the ring could be more silicate rich, whereas another area has more ice. But Hamilton says the researchers “make a good case” for these textures being caused by something other than composition.

    The team inferred that the sharp borders along the ring textures were not due to a composition change, says Tiscareno, but instead result from the physical properties of the ring particles.

    One physical property might be the roughness of ring particles. Tiscareno explains: Is a ring particle more like a billiard ball or more like a snowball? Roughness can affect not only the reflection of light but also how particles interact with each other. “Do they bounce off of each other, like billiard balls do?” he asks. “Or are they kind of sticky, like a snowball would be?”

    Forming a Ring

    Getting close-up data from Cassini gives researchers information that reaches beyond our nearby ringed planet.

    “Rings are our only natural laboratory to understand disk processes more generally,” says Tiscareno. “And that goes to understanding baby solar systems, which are disk systems where you have massive objects that are embedded in the disk.”

    “We’re seeing massive objects embedded in the rings, and we’re seeing the disk itself doing things that we didn’t expect,” he adds.

    Hamilton says that papers like this help uncover how features like propellers might form. “The theory is our imagination,” Hamilton says. Work like this paper, he adds, allows theoretical researchers to be able to test their models on Saturn’s rings against observed data.

    “[These data are going] to be the basis for 10 years of effort by the entire field in trying to figure out how to make all this [propellers, textures] happen,” says Hamilton.

    See the full article here .


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    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 8:52 am on July 15, 2019 Permalink | Reply
    Tags: "Seismic Sensors Probe Lipari’s Underground Plumbing", , , Eos,   

    From Eos: “Seismic Sensors Probe Lipari’s Underground Plumbing” 

    Eos news bloc

    From Eos

    Francesca Di Luccio
    Patricia Persaud
    Luigi Cucci
    Alessandra Esposito
    Guido Ventura
    Robert W. Clayton

    An international team of scientists installed a novel, dense network of 48 seismic sensors on the island of Lipari to investigate the active magma system underground.

    The magma system underneath the island of Lipari, shown here, is connected to a regional fault system formed by tectonic activity rather than to volcanoes like nearby Etna and Stromboli. A research team recently deployed a dense network of seismic sensors to investigate Lipari’s unusual setting. Credit: F. Di Luccio

    Just north of the island of Sicily, near the toe of Italy’s “boot,” a chain of volcanic islands traces a delicate arc in the Mediterranean Sea. This chain, the Aeolian Islands, hosts popular tourist resorts in proximity to some of Earth’s most active and well-known volcanoes, including Etna and Stromboli. Lipari, the largest of these islands, lies just north of the island of Vulcano, for which these eruptive features are named. Lipari is less well characterized than some of the other nearby volcanoes, but one research group is setting out to change this.

    Lipari is located ~80 kilometers north of the well-monitored Etna volcano. The island’s hydrothermal system, in which magma heats the water underground, is not connected to eruptive centers, but, rather, is connected to the regional fault system that delimits the western boundary of the active Ionian subduction zone.

    Lipari holds a unique place in our understanding of the tectonic evolution and hydrothermal activity of volcanoes emplaced in subduction zones. Within the framework of the ring-shaped Aeolian arc, the unexpected NNW–SSE alignment of Lipari and Vulcano has been related to a major regional discontinuity, the Tindari-Letojanni subduction transform edge propagator (STEP) fault, a tear in a tectonic plate that allows one part of the plate to plunge downward while an adjacent part remains on the surface (Figure 1).

    Fig. 1. These tectonic and bathymetric maps show (a) southern Italy and (b) the Aeolian Islands. The bathymetric data are from Ryan et al. [2009]. Major faults are shown as black lines. Regional earthquakes larger than magnitude 3 (black dots) were recorded over the past 3 decades by the permanent Italian seismic network (magenta triangles). Events larger than M 3 that occurred in the time window of the current experiment are shown as cyan stars. The yellow star off the northeastern coast of Sicily shows the location of the 1 November 2018 ML 3.2 earthquake whose waveforms are shown in the left-hand plot of Figure 3. In Figure 1a, blue dashed lines in the Tyrrhenian Sea indicate the isodepths (50, 100, 200, and 300 kilometers) of the slab [Barreca et al., 2014]. Shown in Figure 1b are the locations of Lipari, the Sisifo-Alicudi fault (SAf), and the Tindari-Letojanni STEP fault (STEP-TLf).

    One innovative way to monitor the deep and shallow dynamics of magmatic systems is to deploy dense arrays of seismic sensors over active volcanoes [Hansen and Schmandt, 2015; Ward and Lin, 2017; Farrell et al., 2018]. Thus, to understand Lipari’s unusual setting, we deployed a dense array comprising 48 wireless, self-contained seismic instruments. This is the first time that a dense seismic array has been deployed to investigate a hydrothermal system in the volcanically active Aeolian Islands and the volcanism in the proximity of a STEP fault.

    Transporting the seismic sensors, called nodes, to Lipari required a transatlantic shipment from Louisiana State University (LSU) to Istituto Nazionale di Geofisica e Vulcanologia (INGV) in Rome, followed by a ferry trip to Lipari. Over the course of 2 days, two crews of two people each placed 48 instruments, spaced ~0.1–1.5 kilometers apart, in a wide variety of locales: with homeowners and hotel owners, at the Lipari observatory, on the sides of streets, and buried in the near surface beneath a few centimeters of soil (Figure 2).

    Fig. 2. Three-dimensional perspective view of a Google Earth map of Lipari Island, which covers an area of about 35 square kilometers. The last eruption on this island was in 1220 CE at Monte Pilato. The locations of the ZLand three-component seismic nodes are shown as yellow triangles. A magenta triangle indicates broadband station ILLI of the Italian permanent seismic network. Site photos taken at selected locations are also shown. The inset shows a detailed map of the hydrothermal area (modified from Cucci et al. [2017]) and the locations of photos A, B, and C, which characterize the hydrothermal alteration.

    Researchers from INGV in Rome, the Department of Geology and Geophysics at LSU, and the Seismological Laboratory of the California Institute of Technology deployed the 48 FairfieldNodal ZLand three-component nodes, which have a 5-hertz corner frequency. The nodes recorded one data point every 4 milliseconds from 16 October to 14 November 2018.

    After their transatlantic voyage from Louisiana to Rome, seismic sensors await a ferry trip to Lipari. Credit: A. Esposito

    Lipari’s Tectonic Neighborhood

    Lipari Island belongs to the Aeolian archipelago, a group of subaerial and submarine volcanoes located in southern Italy between the southern Tyrrhenian Sea back-arc basin and the Calabrian Arc, an orogenic belt affected by late Quaternary extensional tectonics. The NNW–SSE Lipari-Vulcano alignment (Figure 1) coincides with the regional tectonic boundary of the Ionian Sea–Calabrian Arc subduction system that is marked by the Tindari-Letojanni STEP fault [Barreca et al., 2014].

    To the west of the archipelago, the WNW–ESE oriented Sisifo-Alicudi fault accommodates shortening related to the eastern termination of the contractional belt (Figure 1). The Tindari-Letojanni and Sisifo-Alicudi fault systems are characterized by shallow seismicity, at depths of less than 25 kilometers, and recorded earthquakes of M 5.8 or less, including the M 4.7 Ferruzzano earthquake in 1978 [Gasparini et al., 1982].

    The Aeolian volcanoes, emplaced on 15- to 20-kilometer-thick continental crust, are the most recent evidence of the magmatism that started during the Pliocene epoch (5.3–2.6 million years ago). This magmatism started in the central sectors of the Tyrrhenian Sea and migrated southeastward toward the Calabrian Arc.

    From about 1 million years ago to the present time, the volcanoes have been producing magma with calc-alkaline, shoshonitic, and alkaline potassic compositions [De Astis et al., 2003; Barreca et al., 2014]. The geochemical affinity of these rocks and the deep seismicity (reaching depths of 550 kilometers) in the southern Tyrrhenian Sea indicate that the Aeolian Islands represent a volcanic arc related to the subduction and rollback of the Ionian slab beneath the Calabrian Arc [Milano et al., 1994; De Astis et al., 2003].

    Early volcanic activity at Lipari ejected lava and rocks into the air, but today, geothermally heated water is more common. Credit: L. Cucci

    Early volcanic activity on Lipari (150,000 years ago and earlier) was concentrated in the western part of the island and focused along north–south aligned vents. Later on, between 119,000 and 81,000 years ago, the Sant’Angelo and Monte Chirica volcanoes deposited lava and pyroclastics (volcanic material that is forcibly ejected into the air) in the central sector of the island (Figure 2).

    From 42,000 years ago to 1220 CE, the activity was concentrated in the southern and northern sectors. This activity included pyroclastics related to subplinian eruptions, domes, and lava flows. Currently, hydrothermal activity (the expulsion of geothermally heated water) characterizes Lipari, Vulcano, and areas offshore of Panarea and Salina. The Lipari hydrothermal field (approximately 0.5 × 0.15 kilometer; see inset in Figure 2) is located along a north–south striking alteration belt in the western and older sector of the island and is characterized by gypsum-filled veins, normal faults with a prevailing NNW–SSE to north–south strike, and active fumaroles.

    Hydrothermalism on Lipari is not associated with centers of recent volcanic activity (less than 40,000 years old), and fluid pathways are strictly controlled by faults and fractures [Cucci et al., 2017]. Vein networks of gypsum (a type of sulfur mineral) affect the hydrothermal system in the lavas and scorias of the oldest Timponi volcanoes, the overlying pyroclastics of Monte Sant’Angelo, the 27,000-year-old Pianoconte pyroclastic deposits, and the present-day soil (inset in Figure 2). The hydrothermal alteration process has been going on for less than 27,000 years and is still active [Cucci et al., 2017].

    A Mountain of Data

    Fig. 3. Seismograms from two earthquakes at local (left) and regional (right) distances recorded at the Lipari array. Vertical components of the ground velocity are low-pass filtered at 5 and 2 hertz for the ML 3.2 and MW 6.8 magnitude events, respectively, to improve the signal-to-noise ratio. Waveforms at the bottom of each plot are the seismograms of the two events recorded by the permanent broadband seismic station ILLI located on the southern tip of Lipari, as shown in Figure 1b, with numbers in bottom left corners indicating the epicentral distances.

    We collected more than 300 gigabytes of data, which include local, regional, and teleseismic (distant) earthquakes as well as ambient noise and volcanic tremor data. During the period of the experiment, about 50 earthquakes occurred within 100 kilometers of Lipari. Half of these had magnitudes of less than 2, but we also recorded 18 events larger than M 5 that occurred in the region and farther away. In Figure 3, we show two examples of recorded seismic waveforms from an ML 3.2 local earthquake and an Mw 6.8 regional earthquake.

    We aim to investigate in detail the crust and upper mantle beneath Lipari Island using receiver functions to characterize Earth’s structural response near the instrument and regional tomography to construct a three-dimensional image of Earth’s nearby interior. We will also analyze ambient noise and local volcanic tremors.

    We plan to merge the seismic data set with other observables such as geochemical measurements and structural data to get a more robust and complete picture of the tectonic setting. We will apply modern and sophisticated processing and analysis techniques used in seismological studies to the nodal seismic array data.

    The deployment of nodal arrays fills a unique niche in monitoring active volcanoes. In comparison to traditional portable seismic stations, nodal arrays enable a high-quality data set to be obtained over a short deployment period, at lower costs, with easier site selection capabilities, and with easy and quick installation procedures.

    Our collaborative field experiment is the latest vehicle for learning about the seismic structure of Lipari and an excellent approach to linking the unrest at depth to volcanic and hydrothermal activity at the surface in similar settings. This project will contribute to the evaluation of the geohazards of the Mediterranean region, where the African and Eurasian plates converge.


    We thank Comune di Lipari for hosting the experiment and INGV Catania and Lipari Observatory (L. Pruiti) for the logistical support. We are grateful to R. Vilardo and M. Martinelli of the Polo Museale di Lipari, Regione Sicilia; the Hotel Antea; Co.Mark and Tenuta Castellaro; and Alessandro (a grocery store) in Acquacalda for hosting some nodes of the experiment. We thank INGV Roma 1 for funding and supporting the project and the Department of Geology and Geophysics at LSU for supporting this project. A.E. was funded by INGV Osservatorio Nazionale Terremoti (ONT). LSU students R. Ajala and E. McCullison assisted with the deployment setup and preparation of the nodes. Data will be available in November 2020 (2 years after the last instrument was retrieved from the field) by contacting the corresponding author.

    Barreca, G., et al. (2014), New insights in the geodynamics of the Lipari–Vulcano area (Aeolian Archipelago, southern Italy) from geological, geodetic and seismological data, J. Geodyn., 82, 150–167, https://doi.org/10.1016/j.jog.2014.07.003.

    Cucci, L., et al. (2017), Vein networks in hydrothermal systems provide constraints for the monitoring of active volcanoes, Sci. Rep., 7, 46, https://doi.org/10.1038/s41598-017-00230-8.

    De Astis, G., G. Ventura, and G. Vilardo (2003), Geodynamic significance of the Aeolian volcanism (southern Tyrrhenian Sea, Italy) in light of structural, seismological, and geochemical data, Tectonics, 22(4), 1040, https://doi.org/10.1029/2003TC001506.

    Farrell, J., et al. (2018), Seismic monitoring of the 2018 Kilauea eruption using a temporary dense geophone array, Abstract V41B-07 presented at 2018 Fall Meeting, AGU, Washington, D.C., 10–14 Dec.

    Gasparini, G., et al. (1982), Seismotectonics of the Calabrian Arc, Tectonophysics, 84, 267–286, https://doi.org/10.1016/0040-1951(82)90163-9.

    Hansen, S. M., and B. Schmandt (2015), Automated detection and location of microseismicity at Mount St. Helens with a large-N geophone array, Geophys. Res. Lett., 42, 7,390–7,397, https://doi.org/10.1002/2015GL064848.

    Milano, G., G. Vilardo, and G. Luongo (1994), Continental collision and basin opening in southern Italy: A new plate subduction in the Tyrrhenian Sea?, Tectonophysics, 230, 249–264, https://doi.org/10.1016/0040-1951(94)90139-2.

    Ryan, W. B. F., et al. (2009), Global Multi-Resolution Topography synthesis, Geochem. Geophys. Geosyst., 10, Q03014, https://doi.org/10.1029/2008GC002332.

    Ward, K. M., and F.-C. Lin (2017), On the viability of using autonomous three-component nodal geophones to calculate teleseismic Ps receiver functions with an application to Old Faithful, Yellowstone, Seismol. Res. Lett., 88(5), 1,268–1,278, https://doi.org/10.1785/0220170051.

    See the full article here .


    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 8:25 am on July 15, 2019 Permalink | Reply
    Tags: "Teams Invited to Test Coastal Hyperspectral Imaging Algorithms", , , , Eos   

    From Eos: “Teams Invited to Test Coastal Hyperspectral Imaging Algorithms” 

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    From Eos

    Margaret A. McManus

    Eric Hochberg

    Hyperspectral Remote Sensing of Coastal and Inland Waters Webinar; 28 May 2019

    Hyperspectral imagery collected by NASA’s Coral Reef Airborne Laboratory (CORAL) shows part of Swain Reefs off the eastern coast of Australia. Participants in a webinar last May planned an upcoming technology demonstration of hyperspectral remote sensing algorithms applied to coastal and inland waters. Credit: Eric Hochberg

    Satellite remote sensing using a few discrete wave bands of light, selected to fit the specific application (multispectral imaging), is a well-established means of monitoring the world’s open oceans. Coastal and inland waters are often much more complex, and the methods used to study these waters are more complex as well. These waters have greater sediment and algal loads than the open oceans, and light can reflect off the bottoms of these shallower water bodies, which complicates data analysis.

    Remote sensing of coastal and inland environments requires hyperspectral imaging—simultaneously measuring tens to hundreds of narrow, contiguous wave bands (typically visible through near infrared)—to disentangle multiple confounding signals. Efficient manipulation of large hyperspectral image data volumes, as well as subsequent generation of meaningful and accurate data products, requires sophisticated algorithms, which continue to evolve and improve.

    In May 2018, participants in the Hyperspectral Imaging of Coastal Waters workshop, sponsored by the Alliance for Coastal Technologies (ACT) and the National Oceanic and Atmospheric Administration (NOAA), recommended a technology demonstration of hyperspectral remote sensing algorithms applied to coastal and inland waters. In May 2019, ACT followed up with an introductory webinar to plan the demonstration.

    Thirty-seven individuals participated in the webinar, representing academic and government research institutions, as well as technology developers from around the globe. There were representatives from ACT, seven members of a technical advisory committee established for this demonstration, four individuals and teams already registered to participate in the demonstration, and seven prospective individuals and teams.

    NOAA established ACT in 2001 to bring about fundamental changes in environmental technology innovation and research and in operations practices. ACT achieves its goal through specific technology transition efforts involving both emerging and commercial technologies. Its efforts include the explicit involvement of resource managers, small- and medium-sized firms, world-class marine science institutions, NOAA, and other federal agencies. ACT’s core efforts are as follows:

    technology evaluations for independent verification and validation of technologies
    technology workshops and webinars for capacity and consensus building and networking
    technology information clearinghouses, including an online technologies database

    For the hyperspectral technology demonstration, ACT is inviting individuals and teams with established processing routines and algorithms to work with highly described hyperspectral data sets and corresponding in situ validation data sets. The goal of the demonstration is to evaluate the capabilities and maturities of various algorithms. This exercise is not a research project; rather, it is an opportunity to enhance communication within the community and to advance future applications of hyperspectral remote sensing in coastal waters.

    Three views of the Torres Strait, between Australia and Papua New Guinea, from the CORAL mission illustrate an example of applied hyperspectral data: pseudotrue color image of 12 flightlines were acquired by the Portable Remote Imaging Spectrometer (PRISM) on 12 October 2016 (left); the results of CORAL data processing estimate the probabilities that image pixels are dominated by coral, algae, or sand (middle); and a map of the percentages of coral-dominated pixels in 1 × 1 kilometer grid cells, which enables researchers to fulfill CORAL’s science objective of investigating reef condition in relation to large-scale biogeophysical forcings (right). PRISM data collected for CORAL are freely downloadable.

    Data sets being used in the hyperspectral algorithm technology demonstration characterize kelp forests, coral reefs, harmful algal blooms (including those in inland waters), sea grass, and water quality. It is not required that all individuals and teams work with all data sets. Individuals and teams will select the data sets they are most familiar with, and they are welcome to work with more than one data set or contribute additional data sets that will be made available to all demonstration participants.

    The resulting data products are useful to scientists developing a greater understanding of these natural systems, as well as to resource managers tasked with conservation and decision-making. The data products also support future hyperspectral missions such as NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) and Surface Biology and Geology (SBG).

    The hyperspectral algorithm technology demonstration will be conducted over a 4- to 6-month time frame. The original request for technology was released 20 March 2019. The deadline for individuals and teams to register to participate is 31 August 2019.

    ACT anticipates an additional webinar or in-person workshop in fall 2019. Technology demonstration results will then be shared in a final workshop at the University of Hawai‘i at Mānoa in winter 2020. The overarching goal of the demonstration includes publishing individual project results and synthesis papers on learned best practices. Several manuscripts and a final report are expected to result from these collaborations.

    ACT continues to accept applications to participate in the demonstration. Please contact Thomas Johengen with expressions of interest. ACT will pay for travel costs for one to two members of each team to attend workshops.

    See the full article here .


    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 7:34 am on July 11, 2019 Permalink | Reply
    Tags: "New Proof That Accretion Disks Align with Their Black Holes", , , , , Bardeen-Petterson alignment, , Blue Waters Cray Linux XE/XK hybrid machine supercomputer, , Eos   

    From Eos: “New Proof That Accretion Disks Align with Their Black Holes” 

    Eos news bloc

    From Eos

    10 July 2019
    Rachel Crowell

    An image of an accretion disk around a black hole, as seen by an observer nearly edge on to the disk. Credit: NASA GSFC/J. Schnittman

    In 1975, physicist James Bardeen and astrophysicist Jacobus Petterson theorized the existence of a black hole phenomenon that researchers have since been scrambling to show.

    In a study published in the July issue of Monthly Notices of the Royal Astronomical Society, researchers announced that they finally demonstrated Bardeen-Petterson alignment, in which a spinning black hole causes the inner portion of a tilted accretion disk to align with the black hole’s equatorial plane. Finding this effect could change our understanding of how black holes grow and how their presence affects galaxies, according to Sasha Tchekhovskoy, a computational astrophysicist at Northwestern University and colead author of the study.

    In this image, the inner region of the accretion disk (red) aligns with the equatorial plane of the black hole, while the outer disk tilts away. The inner disk (where the black curve dips) is horizontal due to Bardeen-Petterson alignment. Credit: Sasha Tchekhovskoy/Northwestern University and Matthew Liska/University of Amsterdam.

    Powerful Resources Fueled the Simulation

    To accomplish the most detailed and highest-resolution black hole simulation to date, Tchekhovskoy and his team used the Blue Waters supercomputer at the University of Illinois at Urbana-Champaign.

    NCSA U Illinois Urbana-Champaign Blue Waters Cray Linux XE/XK hybrid machine supercomputer

    They also used adaptive mesh refinement, a research method that uses grids that change in response to movements within simulations, and a technique called local adaptive time stepping to bring down the simulation cost by 2 orders of magnitude.

    “It’s very difficult to model the [accretion] disks that show this effect” because they are extremely thin, said Tchekhovskoy. Using graphical processing units instead of central processing units (previously used in similar black hole simulations) enabled the team to “simulate the thinnest disks to date,” Tchekhovskoy said.

    These thin accretion disks have height-to-radius ratios of 0.03, and Tchekhovskoy says the team was surprised to discover that “all of these interesting effects,” including Bardeen-Petterson alignment, appear at that thickness. The thinnest disks simulated prior to this study were more than 1.5 times thicker.

    Cole Miller, an astrophysicist at the University of Maryland in College Park who wasn’t involved with the new study, said he’s impressed with the level of detail in the simulation.

    Unexpected Jets

    “A major surprise of this work is the finding of powerful jets, even in our thin disc accretion system,” the researchers wrote in the study.

    The finding runs counter to the team’s expectation that magnetic fields would rip through the thin accretion disks rather than producing jets, Tchekhovskoy said. Exploring this finding in future work could provide insights into a different phenomenon, he added: why only about 10% of bright, supermassive black holes produce these jets.

    Putting Bardeen-Petterson in Context

    Miller noted that some initial coverage of the new study incorrectly identified John Bardeen, James’s father and a two-time winner of the Nobel Prize in Physics, as one of the two people after which the Bardeen-Petterson effect is named.

    Besides theorizing the Bardeen-Petterson alignment, James Bardeen, now professor emeritus at the University of Washington in Seattle, is also known for formulating (with Stephen Hawking and Brandon Carter) the laws of black hole mechanics. Jacobus Petterson, who died in 1996, was “best known in the astronomical community for his analysis of X-ray binary systems,” according to an obituary written for the American Astronomical Society.

    “This groundbreaking discovery of Bardeen-Petterson alignment brings closure to a problem that has haunted the astrophysics community for more than four decades,” Tchekhovskoy said in a statement.

    “It’s an interesting paper and definitely takes things a step or two beyond previous work,” according to Julian Krolik, an astrophysicist at the University of California, Berkley, who wasn’t involved with the study.

    However, Krolik disagrees about the overall importance of the paper. “It’s not ‘ground-breaking,’ nor does it provide ‘closure.’ ‘Closure’ in this field would mean identification of all the principal mechanisms regulating where the steady-state orientation transition takes place, construction of a method to predict (given relevant disk parameters) the location of this transition, and definition of the boundaries in parameter space separating where alignment is successful and where it isn’t,” Krolik wrote in an email to Eos.

    There is one major question that Krolik said the researchers leave unanswered: why the accretion disk alignment “extends to only a short distance from the black hole, stopping far short of where they expected it to reach.”

    See the full article here .


    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 9:51 am on June 11, 2019 Permalink | Reply
    Tags: "Seeing the Light", , , , , Eos, , Lunar research   

    From Eos: “Seeing the Light” 

    From AGU
    Eos news bloc

    From Eos

    Damond Benningfield

    Apache Point Observatory’s laser fires at the Apollo 15 retroreflector during a lunar eclipse in 2014. Credit: Dan Long, Apache Point Observatory

    Apache Point Observatory, near Sunspot, New Mexico Altitude 2,788 meters (9,147 ft)

    When Neil Armstrong and Edwin “Buzz” Aldrin blasted off the Moon on 21 July 1969, they left a couple of packages at Tranquility Base. One was a solar-powered seismometer that collected 21 days of observations before expiring in late August. The other was an aluminum frame filled with chunks of fused-silica glass that looked a bit like a high-tech egg crate.

    Along with similar devices left on the Moon by Apollo 14 and 15, the instrument is still working—the only Apollo surface experiment that continues to provide data.

    Known as a lunar laser ranging retroreflector, it bounces pulses of laser light back to their sources on Earth. Scientists time the round-trip travel time of each pulse, allowing them to measure the Earth-Moon distance to within a millimeter. A half century of these observations has provided precise measurements of the shape of the Moon’s orbit, wobbles in the Moon’s rotation, and other parameters. Those, in turn, have helped scientists determine the Moon’s recession rate, probe its interior structure, and test gravitational theory to some of the highest levels of precision yet obtained.

    “This is a venerable technique that’s provided some of our best science about how gravity works,” says Tom Murphy, a professor of physics at the University of California, San Diego, who has headed a lunar laser-ranging project since the early 2000s.

    Peculiar Prisms on the Moon

    The devices left on the Moon by Apollo astronauts (as well as two others aboard Soviet Lunokhod rovers) consist of arrays of corner cube reflectors.

    McDonald Observatory’s 2.7-meter telescope beams a laser toward the Moon. The telescope, part of the University of Texas at Austin, conducted laser observations from 1969 to the mid-1980s, when laser ranging was moved to a smaller telescope. Credit: Frank Armstrong/UT Austin

    U Texas at Austin McDonald Observatory, Altitude 2,070 m (6,790 ft)

    “These are like peculiar prisms—they’re shaped like the upper corner of a room,” says Doug Currie, a professor of physics at the University of Maryland in College Park who has worked in the field since the 1960s. “You could throw a tennis ball in the corner, and it would hit all three sides and bounce back to you. The lunar reflectors do the same thing. The difference is, you can send up to 1023 photons at a time, and you’re happy when one comes back.”

    The Apollo 11 and 14 retroreflectors each contain one hundred 3.8-centimeter corner cubes, whereas the Apollo 15 array contains 300, so it produces the strongest return signal.

    Photons are beamed toward the Moon through a telescope, such as the 3.5-meter telescope at Apache Point Observatory in New Mexico, the largest instrument ever to conduct lunar laser ranging. The laser is fired in 100-picosecond pulses—“bullets of light” just 2 centimeters thick, says Murphy, who heads the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO).

    No more than a few photons from each pulse return to the telescope, but the telescope fires thousands of laser bullets during each ranging session, allowing it to collect thousands of photons per session. Statistical analysis smooths out the differences in ranges between individual photons, producing a distance to the Moon with an accuracy of about 1 millimeter.

    APOLLO ranges to the Moon about six times per month and targets all five of the retroreflectors during each session. France’s Observatoire de la Côte d’Azur, the other major lunar-ranging station, uses a smaller telescope but has begun ranging with an infrared laser, which is about 8 times more efficient than the standard green laser.

    An Array of Scientific Contributions

    All five of the current lunar retroreflectors are located near or north of the Moon’s equator, leaving the southern hemisphere uncovered. Credit: NASA

    Lunar laser ranging’s first scientific contribution was to produce an accurate measurement of how quickly the Moon is moving away from Earth: 3.8 centimeters per year. The retreat is the result of the ocean tides on Earth, which cause our planet’s rotation rate to slowly increase. To balance the books on the overall motion of the Earth-Moon system, the Moon speeds up, causing it to move away from Earth.

    Collecting data from the network of five retroreflectors over the course of several decades also has allowed planetary scientists to probe the Moon’s interior by measuring how the Moon “wobbles” on its axis.

    Some of those wobbles are caused by the Moon’s elliptical orbit, but others are produced by motions within the Moon itself. Measurements of that interior “sloshing” revealed that the Moon has a liquid outer core that’s about 700 kilometers in diameter, roughly 20% of the Moon’s overall diameter.

    “Everybody came in thinking, ‘we really know the Moon,’ but we didn’t,” says Peter Shelus, a research scientist at the University of Texas at Austin, which conducted lunar laser-ranging operations for more than 40 years. “We didn’t know the lunar rotation as well as we thought. As we got more data, though, everything fell into place, and the rotation rate allowed us to probe the interior.”

    When the lunar laser-ranging experiment was conceived in the early 1960s, however, learning about the Moon itself was a secondary goal. The primary goal was to study gravity. And so far, laser ranging has confirmed Isaac Newton’s gravitational constant to the highest precision yet seen and confirmed other tenets of gravitational theory, including the equivalence principle, which says that gravitational energy should behave like other forms of energy and mass.

    “What we’re after, the flagship science, is the strong equivalence principle,” says Murphy. “By, quote, dropping Earth and the Moon toward the Sun, we can use the Earth-Moon separation as a way to explore whether two bodies are pulled toward the Sun differently. That’s a foundational tenet of general relativity, and it would be very important if we saw a violation there.”

    So far, the lunar laser-ranging experiment has confirmed relativity’s predictions about the equivalence principle to the highest precision yet seen—within the experiment’s margin of error, Earth and the Moon “fall” toward the Sun at the same rate.

    “There’s Still Work to Do”

    Despite the experiment’s success, Murphy says he’s “disappointed” in the results to date.

    “We’ve managed to produce measurements we’re all confident in at the millimeter level of accuracy, but the model that it takes to extract science from this result has been slow to catch up. So we haven’t yet seen the order-of-magnitude level of improvement that we hoped for in those tests. We’ve seen maybe a factor-of-2 level of improvement, but that’s not very satisfying.”

    James Williams, a senior research scientist at NASA’s Jet Propulsion Laboratory and another pioneer in the lunar-ranging field, agrees that there’s work to do to improve our understanding of the results.

    “We’ve measured the Earth-Moon acceleration toward the Sun to 1.5 parts in 1013, which is a very, very sensitive test. It limits certain gravitational theories,” Williams says. “But there’s stuff in the model and in the data that we still don’t understand. There’s still work to do.”

    While the models catch up, the observational side of the project could stand some improvement as well, scientists say.

    The Lunokhod reflectors, for example, can be used only around sunrise and sunset; thermal problems scuttle observations at other points in the lunar cycle. The Apollo reflectors are degrading, probably because micrometeorite impacts on the surface are splashing dust onto the corner cubes. All of the current retroreflectors are placed near or north of the equator, leaving the southern half of the lunar globe uncovered. And current ranging is so precise that the orientation of the retroreflectors can cause a problem: As the laser bounces off opposite corners of an array, it can increase uncertainty in the measurements by a few centimeters.

    Currie has proposed sending new reflectors to the Moon using a new corner cube design.

    “We’ve been working on a 100-millimeter glass reflector that’s basically a scaled-up version of the Apollo reflectors,” he says. “You don’t have to worry whether a returned photon came from the near corner or the far corner of an array. We think that’ll improve the accuracy of a shot by a factor of a hundred. We’ve had to solve some thermal issues with the reflectors and the frame, but we can put together a package that can fly.”

    Currie’s group has submitted proposals to NASA to strap one of the new modules on an upcoming lunar mission and has signed an agreement with Moon Express, a company vying to launch a lander.

    “If you’re going to the Moon, these are almost no-brainer accompaniments,” says Murphy. “Their success is almost guaranteed; they require no power, they’ll work for decades and decades….It’s a low-cost, high-reward investment, which is why it was included on the initial Apollo mission.”

    It’s an investment that’s still paying dividends 50 years later.

    See the full article here .


    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 11:03 am on June 7, 2019 Permalink | Reply
    Tags: "Women in Oceanography Still Navigate Rough Seas", , Discrimination against women in the sciences still rages and it is our loss., Eos,   

    From Eos: “Women in Oceanography Still Navigate Rough Seas” 

    From AGU
    Eos news bloc

    From Eos

    Jenessa Duncombe

    Scientist inspects a sample of plankton on a research ship. Credit: Cultura/Monty Rakusen/Getty Images

    In 1872, the British Challenger expedition sailed around the globe on a voyage to study and sample the world’s oceans. The expedition is thought to be the first scientific oceanographic cruise.

    Of the 243 people on board the Challenger, not one was a woman. Women weren’t allowed on ships, research or otherwise.

    But nearly a century before the Challenger, a woman by the name of Jeanne Baret sailed around the world on a scientific expedition of her own. Baret disguised herself as a male assistant on a 1766 voyage led by the French admiral and explorer Louis-Antoine de Bougainville to document plants and ecosystems in distant countries. Baret is the first woman on record to have circumnavigated the globe.

    Science, especially science on ships, has a long history of excluding women. And since the beginning, women like Baret have undermined and pushed back against the rules. Women finally secured the ability to participate in scientific cruises in the United States in 1959 and now lead expeditions, research institutions, and federal agencies.

    Contemporary oceanographers face less obvious problems: a culture of scientific research founded in exclusion and still grappling with explicit and implicit bias, unsafe work environments, and a lack of institutional support.

    Robin Nelson, a biological anthropologist at Santa Clara University who studies issues of harassment and assault, said that discrimination threatens the meritocratic nature of science itself.

    “We frame science as this idea that folks with the best ideas, folks who are willing to work hard, are those who are going to succeed,” Nelson told Eos. But without safeguards protecting vulnerable scientists, she said, “those folks who could be supertalented, wonderful scientists get pushed out of our fields.”

    Peter Girguis, an oceanographer at Harvard University, agrees. “In the absence of gender equality, we’re doing mediocre science,” Girguis said.

    For the 2019 World Oceans Day theme of “Gender and the Ocean,” the United Nations writes that the empowerment of women and girls is “still needed” in all aspects of ocean-related sectors, including marine scientific research.

    The theme begs the question: What barriers do modern women face in the ocean sciences, particularly those working in the field? And how can recent upgrades in technology, policy, and cultural awareness counteract these issues?

    Potholes to Progress

    The rate of women’s professional involvement in oceanography is sometimes referred to as a “leaky pipeline.” Initially, the flow of young women into the profession is strong but dwindles as they choose to leave for numerous reasons.

    Women and men enroll in undergraduate and graduate programs in oceanography in equal numbers, according to a 2014 study in Oceanography. (Numbers for gender-nonconforming individuals were not reported.) But only 15% of full or senior faculty positions across 26 U.S. institutions were held by women in 2014. The authors found that women “continue to drop out as they progress along the tenure track,” which they note is similar to other disciplines in science.

    they progress along the tenure track,” which they note is similar to other disciplines in science.

    LuAnne Thompson, a physical oceanography professor at the University of Washington, said that the field has been trying to fix the leaky pipeline for decades.

    “People recognized it was a problem, but they thought of quick fixes,” Thompson said. Initiatives pushed the hiring of more female faculty in the 1990s, she said, but gave little thought to the cultural change needed to support them.

    The result left women navigating a landscape of potholes throughout their careers. One woman deliberated over whether to mention her family in a job interview. Another noticed how she was spoken over at meetings. And still others struggled with the aftermath of harassment and assault.

    Women belonging to marginalized groups, including people of color, LGBTQ+ individuals, and people of differing abilities, face heightened obstacles in the sciences. Marine geologist and chief Esri scientist Dawn Wright said that although the number of women may be increasing in the field, the number of women of color is not.

    “I can count other African American women in oceanography on one or two hands,” Wright told Eos. “That really needs to change.”

    To learn more about the challenges faced by female oceanographers in their everyday lives, Eos spoke with working oceanographers across disciplines. From outright bias to lackluster university support, from subtle discrimination to sexual assault, female scientists described a suite of challenges that build up over time, becoming what one researcher called a “death by a thousand cuts.”

    But just as female scientists struggled against cultural and structural barriers in the past, modern women have found ways to overcome and cope with inequality. Their actions, both interpersonal and policy facing, are part of the movement to rewrite an exclusive culture’s rules, just as Jeanne Baret did centuries before.

    “Isn’t That a Man’s Job?”

    When Asha De Vos left her home in Sri Lanka to pursue an education in Scotland, she said, “most people were convinced I would never come home.”

    De Vos had dreamed of a life as a marine biologist from a young age. But when she told others of her aspiration, she said, “most people had never heard of [it].” There were simply no marine biologists in Sri Lanka, despite it being an island nation.

    Marine scientist Asha De Vos and her team heading to sea to study blue whales off the coast of her native Sri Lanka. Credit: Erik Olsen

    After obtaining her Ph.D., De Vos returned home, where she studies populations of blue whales in the northern Indian Ocean, focusing on conservation and reducing instances of ship strikes. But government officials in Sri Lanka long ignored her recommendations, according to De Vos, often favoring the advice of men less qualified than she was.

    “They were invited to meetings and listened to, despite the fact that what they had to say was nothing concrete,” De Vos told Eos.

    De Vos frequently chafed against the male-driven society of Sri Lanka, coping with outright discrimination and bias.

    “They’ll continuously say things like, ‘Oh, but isn’t that a man’s job?’” said De Vos.

    After she appeared on an international television program speaking about her research, De Vos faced sharp criticism. When the video showed up as a clip on YouTube, De Vos called the video comments “horrific.”

    “I genuinely cried for about 4 hours reading them,” she recalled.

    De Vos found most of the criticism fixed on her gender, not her credibility.

    “I was at that point, and still am today, the only person with this kind of knowledge in this entire country,” she said. Still, critics “weren’t valuing me on what my capacity [was], but they were basically attacking me on my physical appearance.”

    “As a Human, I’m Not Addressed”

    Seagoing oceanographer Ivona Cetinic remembered hearing flack early in her career, like being told that because she was a woman, she “shouldn’t be doing certain things.”

    Oceanographer Ivona Cetinic preps instruments for a research cruise aboard the Schmidt Ocean Institute’s R/V Falkor in 2017. Credit: NASA

    Schmidt Ocean Institute RV Falkor

    As she advanced in her career, the comments stopped, and in their place, Cetinic faced a new type of barrier: a lack of institutional support for women starting families.

    Cetinic typically sailed on one or two long cruises per year as well as frequent daylong trips, retrieving new field data of phytoplankton populations to inform satellite images. In 2013, she planned to attend a cruise shortly after the birth of her first child. Since she had a nursing newborn, she didn’t want to throw away her milk while at sea.

    Cetinic checked the website of the organizational body in charge of university vessels, the University-National Oceanographic Laboratory System (UNOLS), for recommended procedures for lactation at sea. She discovered that the information didn’t exist. This realization came on the heels of another experience, months before, in which she couldn’t find clear guidelines regarding attending a cruise while pregnant.

    “There was, once again, no clear documentation that I could follow,” Cetinic said.

    Cetinic turned to Twitter and connected with women facing similar challenges, who recommended she bring a freezer on the ship to store her milk. Thanks to her network, she knew what to do on her upcoming cruise, but when it came to university policy, there was a lack of support for her needs.

    “As a human, I’m not addressed,” she said.

    “End of My Patience”

    Women in oceanography also cope with instances of sexual harassment and assault.

    Oceanographer Julia O’Hern, manager at the nonprofit Marine Mammal Center in Moss Landing, Calif., published an account in the Washington Post in 2015 describing her experiences facing discrimination, harassment, and assault while working on research ships as boat crew and as a scientist for her postdoctoral research at Texas A&M.

    Julia O’Hern responding to a sea lion entanglement issue in California while working for The Marine Mammal Center in 2018. Credit: Julie Steelman, The Marine Mammal Center

    O’Hern recounted a list of unwanted behaviors by coworkers, who made comments about her body and suggested that she wasn’t hirable because of her gender. One colleague’s behavior took a turn for the worse, O’Hern wrote, when he entered her room at night and groped her.

    O’Hern reported several instances of misconduct through numerous channels, including the National Oceanic and Atmospheric Administration (NOAA) and her university. O’Hern told Eos that after 3 years of investigations, the institutions decided that there was “insufficient evidence or jurisdiction.”

    After speaking out, O’Hern said she was not able to finish her postdoctoral project and lost several important professional relationships. Although she knew that going public about her experience would come with repercussions, O’Hern said that she couldn’t stay silent any longer.

    “I was just at the end of my patience level with certain behaviors,” O’Hern said. After finishing her Ph.D. and working hard on her shifts, it was just too insulting, she said, to “‘suck it up’ and ignore it.”

    She hoped that the article could open a conversation about not just assault but the culture of discrimination that women endure.

    “It’s hard when we feel like we can only talk about these things after it becomes a criminal case,” she said. “If we were to nip it in the bud a little earlier, we wouldn’t have to get to this horrible level.”

    Not Alone

    Not all women experience discrimination in science: Some have fulfilling careers and choose to stay or leave the field on their own terms. But the experiences of De Vos, Cetinic, and O’Hern mirror those of many others in oceanography, including experiences documented in published literature. The discrimination described by De Vos echoes an ethnography published in 2018 describing the culture of the Ocean Observatories Initiative, where project scientists chronicled instances of explicit and implicit bias. Several recent quantitative studies have also illuminated subtle biases in hiring, manuscript reviewing, and letters of recommendation in the geosciences.

    The dearth of support for new parents, recounted by Cetinic, parallels complaints of more than 200 autobiographical sketches of female ocean scientists outlined in a 2014 special issue in Oceanography. Nearly every sketch mentioned issues with work-life balance, and the special issue’s editor, Ellen Kappel, called it the “biggest challenge” facing women in science today.

    Instances of sexual harassment and assault, like those experienced by O’Hern, are frighteningly common across the sciences. Although no study on the prevalence of harassment and assault exists for oceanography, a 2014 PLoS ONE survey of over 600 scientists from fieldwork-intensive disciplines found that nearly two thirds of the survey respondents had personally experienced sexual harassment and close to a quarter had experienced sexual assault while conducting fieldwork. The study did not have a random sample and therefore cannot represent the prevalence of harassment and assault, but the study’s authors write that the findings reveal a “substantial degree” of problematic behavior in the sciences.

    New Policies, Technology, and Cultural Conversations Offer Hope

    Scientist Marta Torres (left) and marine geologist Dawn Wright (right) dressed as “roughnecks” on an Ocean Drilling Project cruise in 1989. Credit: John Beck

    Can recent shifts in policy, technology, and cultural norms make science more equitable? And how are women, with actions both big and small, rewriting the culture of oceanography to bolster all scientists?

    Shortly after O’Hern published her article in the Washington Post, staffers from the office of Sen. Charles Grassley (R-Iowa) reached out.

    An effort was underway in the legislature to clarify NOAA’s policy for reporting harassment and assault on vessels, and they wanted O’Hern’s input. She worked with legislatures to introduce policy to ease victims’ experiences reporting to NOAA.

    The new policy added several safeguards to support victims of harassment and assault. A new 24-hour hotline eases reporting from ships, letting victims report without the use of the boat’s often public and limited phone or radio channels. Under the new policy, anyone working on a NOAA vessel—from employees to contractors to university affiliates—will have the power to report, and be reprimanded, through the agency. This patches a loophole that O’Hern faced while reporting issues as a contracted deckhand and university scientist.

    Scientific societies and organizations are revising scientific policies to better protect scientists. The Oceanography Society (TOS) listed harassment and assault as scientific misconduct in late 2018 and created an ethics committee to investigate reported cases of misconduct. AGU instituted a similar policy in 2017 and recently created free legal consultations for students, postdoctoral researchers, and untenured faculty.

    Oceanographer Katy Croff Bell leads the Open Ocean initiative at the MIT Media Lab. Credit: Kris McMillan.

    Calls for better resources for women with children helped spur the creation of a UNOLS ad hoc committee to address the working conditions on the organization’s 21 research vessels. The group sent out recommended policies to ship operators for pregnant women and nursing mothers in 2016, which cochair Mark Brzezinski said many operators adopted.

    Telepresence on ships gives pregnant mothers and others a new way to participate in research cruises. Katy Croff Bell, a deep-sea explorer at the Massachusetts Institute of Technology (MIT), said that this technology has been used on research vessels for many years, like NOAA’s R/V Okeanos Explorer and the Ocean Exploration Trust’s E/V Nautilus.

    Finally, shifts in awareness offer hope. Nelson, who publishes papers on harassment and assault in science, said that initially, her colleagues brushed off her work. But after the #metoo movement, “that’s not a discussion anymore,” said Nelson.

    Thompson said that conversations about diversity have evolved since she was hired in the 1990s.

    “Now we’re in a place where the broader academic community is talking about diversity and culture and implicit bias and privilege,” said Thompson. The conversations go “beyond just women” to include ethnic and socioeconomic diversity, she added. Programs like Minorities Striving and Pursuing Higher Degrees focus on professional development for underrepresented minorities in the geosciences.

    Peter Girguis said that men can support and champion women in science as well. He encourages men to be aware of their biases and hear what women have to say. “Being inclusive and supportive of women is about listening and understanding individual needs,” he said.


    For De Vos, she said that she took refuge in building strong partnerships and in the support from her parents. She started to see those who lashed out at her as jealous of her ability and took it as a sign that she was “doing something right,” she said.

    These changes, said De Vos, “allowed me to just start to build self-belief that told me that, you know what? It doesn’t matter in the end,” De Vos said. “The ocean needs me more than what these people have to say.”

    After years of working to engage the government in marine conservation issues in Sri Lanka, she said, a government minister finally reached out and asked for her advice.

    Cetinic agreed that a supportive community and mentorship can be transformative. “It’s very hard to take a step into the unknown if there’s nobody down there to catch you if you fall,” she said.

    These women, and many others, take solace in the joys of their community, their families, and the ever-present pull of ocean exploration.

    O’Hern still works on boats, coordinating ship efforts to rescue and rehabilitate injured marine mammals. As she wrote in the Washington Post, “Why should I or other women pursue careers in which our colleagues devalue us in this manner? Because discrimination will never compare to the joy of sailing out toward the clouds, salt spray soaking the air.”

    See the full article here .


    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 12:30 pm on May 14, 2019 Permalink | Reply
    Tags: , Bárðarbunga-Eruption at Holuhraun September 4 2014, Eos,   

    From Eos: “More Than 30,000 Earthquakes Trace the Movement of Magma” 

    From AGU
    Eos news bloc

    From Eos

    Katherine Kornei

    Seismometers near Iceland’s Bárðarbunga volcanic system pinpointed thousands of earthquakes in 2014–2015, revealing where molten rock was moving underground before any eruptions occurred.

    Bárðarbunga-Eruption at Holuhraun, September 4, 2014, https://www.flickr.com/photos/41812768@N07/15146259395/

    As Iceland’s Bárðarbunga volcanic system erupts in the background, researcher Jenny Woods downloads data from a seismometer. Image courtesy of Cambridge Volcano Seismology. Credit: Jenny Woods

    Accurate forecasting of volcanic eruptions is life-saving science: Millions of people worldwide live in the shadow of a volcano.

    Researchers have now analyzed precise records of tens of thousands of earthquakes in Iceland and produced one of the most detailed pictures of how seismicity traces the movement of magma deep underground. These kinds of measurements, which reveal the location of molten rock, can be used to better predict when and where eruptions will occur, the scientists suggest.

    Lucky Placement

    Robert White, a geophysicist at the University of Cambridge in the United Kingdom, admits he was lucky. He and his colleagues on the Cambridge Volcano Seismology team had already installed over 60 seismometers near Iceland’s Bárðarbunga volcanic system when magma began moving underground in 2014.

    The instrumentation was intended for a neighboring volcano, but White and his collaborators soon realized the seismometers were perfectly placed to capture the rumblings of Bárðarbunga. “They were in just the right place,” said White. (The researchers also rushed to place 10 additional seismometers.)

    Bárðarbunga would go on to belch 1.6 cubic kilometers of molten rock, dwarfing the 2010 eruption of Eyjafjallajökull. The first eruption occurred for a few hours on 29 August, and the next one came on 31 August, this time lasting 6 months.

    Earthquakes and volcanic eruptions often go hand in hand: The movement of molten rock underground—a magmatic intrusion—triggers ground shaking as it deforms the surrounding rock.

    The Bárðarbunga magmatic intrusion cut a 48-kilometer-long path through Earth’s crust over the course of 2 weeks. And earthquakes were plentiful: White and his colleagues recorded over 30,000 ranging in magnitude from 0.5 to 3.5.

    Precise Triangulation

    White and his colleagues pinpointed the locations of the earthquakes in three-dimensional space by triangulation. By very precisely measuring—to within 0.001 second—how long it took the earthquake waves to travel to different seismometers, the researchers estimated locations with uncertainties of only about 100 meters. That’s about 10 times better than most other studies, said Jenny Woods, a volcano seismologist at the University of Cambridge and member of the research team.

    Using the locations of the recorded earthquakes, the researchers inferred that Bárðarbunga’s magma moved in fits and starts—sometimes it stalled, and sometimes it moved forward at nearly 5 kilometers per hour (roughly human walking speed).

    These kinds of measurements make it possible to track the path of magma underground, said Woods. “Monitoring microseismicity is one of the most important tools we have for tracking intrusions of magma in real time.”

    Their results were published earlier this year in Earth and Planetary Science Letters.

    This study highlights the importance of having a dense monitoring network, said Luigi Passarelli, a volcanologist at King Abdullah University of Science and Technology in Saudi Arabia not involved in the research. “[It] can lead to better understanding of physical processes and eventually to improved real-time risk mitigation.”

    White and his colleagues will be returning to Iceland this July to download data from the 27 seismometers still deployed around Bárðarbunga. Collecting these measurements is crucial because the volcano appears to be refilling with magma underground, said White. “It’s still active.”

    See the full article here .


    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 1:34 pm on April 24, 2019 Permalink | Reply
    Tags: "Bringing Clarity to What Drives Auroras", , , , , Eos   

    From Eos: “Bringing Clarity to What Drives Auroras” 

    From AGU
    Eos news bloc

    From Eos

    Mark Zastrow

    In this image taken from the International Space Station, both diffuse and intense auroras are visible, produced by charged particles propelled into Earth’s atmosphere. Credit: NASA

    The most spectacular auroras are produced by electrons zipping from space into Earth’s atmosphere. Although Earth’s magnetic field repels most electrons before they reach any wisps of air, under special conditions they can penetrate into the atmosphere, striking air molecules and causing them to glow.

    But how exactly those electrons, which normally circulate in Earth’s magnetic field, are accelerated or pushed down into the atmosphere is not fully clear.

    It’s generally agreed that there are three main ways to generate this “auroral precipitation.” One is small pockets of strong electric field high above Earth—also known as quasi-static potential structures (QSPS)—which can whisk them down. Another is strong waves in Earth’s magnetic field in which field lines vibrate like a plucked string—called Alfvén waves—propelling the charged particles along. These two mechanisms produce the most intense bands, curtains, and sheets of auroras.

    The other main cause is higher-frequency waves in Earth’s magnetic field that don’t increase electrons’ speed but scatter them, nudging the particles into trajectories that carry them down into the atmosphere. Wave scattering produces a less vivid, diffuse auroral glow but is commonly thought to be responsible for the bulk of the total auroral energy.

    But it’s difficult to decipher which of these three is happening at any given time. They can be identified only indirectly by analyzing spacecraft data measurements. Plus, these different mechanisms can occur simultaneously, which researchers have been unable to disentangle.

    Now, Dombeck et al. [JGR Space Physics] have developed a classification scheme that resolves many of these ambiguities and can detect multiple mechanisms. Their method used 13 years of data from NASA’s Fast Auroral Snapshot Explorer (FAST), a satellite launched into Earth orbit in 1996.

    NASA Fast Auroral Snapshot Explorer (FAST)

    Crucially, its instruments can observe electrons traveling both down toward Earth and up into space. In contrast, the previous, widely used scheme was based on data from satellites that could measure only downward traveling electrons and could identify only a single mechanism at a time.

    Being able to see upward traveling electrons makes it easier to determine whether they were accelerated by electric field structures or magnetic field vibrations, as the former reflect upgoing electrons back toward Earth and the latter do not. When the team compared their results, they found that misclassifications were common under the previous scheme.

    Applying their method to FAST data paints a complex picture of electron precipitation: Most of the time, multiple mechanisms contribute, and frequently, all three appear in intense auroral storms.

    Intriguingly, their results may also contradict the view that wave scattering contributes most of the energy of electron precipitation: The authors found that on Earth’s nightside, two thirds of the energy input comes from intense precipitation that is mostly caused by QSPS and Alfvén waves.

    Using this new method to better understand the mechanisms responsible for auroral precipitation will also help scientists better understand how Earth’s magnetic fields interact with the stream of charged particles coming from the Sun and how this interaction produces hazardous solar storms.

    See the full article here .


    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 2:35 pm on April 23, 2019 Permalink | Reply
    Tags: "National Volcano Warning System Gains Steam", Eos, Eruptions have the potential to pose significant security and economic threats across the nation., It took more than a decade but a bill that funds U.S. volcano monitoring efforts and establishes a single system became law on 12 March., Kīlauea Volcano in Hawaii, Mount St. Helens in Washington State, Passage of Public Law No. 116-9 authorizing funding for the implementation of the NVEWS was introduced by Sen. Lisa Murkowski (R-Alaska), Since 1980 there have been 120 eruptions and 52 episodes of notable volcanic unrest at 44 U.S. volcanoes, Volcano Observatories: Alaska Volcano Observatory; California Volcano Observatory; Cascades Volcano Observatory; Yellowstone Volcano Observatory; Hawaiian Volcano Observatory,   

    From Eos: “National Volcano Warning System Gains Steam” 

    From AGU
    Eos news bloc

    From Eos

    Forrest Lewis

    It took more than a decade, but a bill that funds U.S. volcano monitoring efforts and establishes a single system became law on 12 March.

    The string of 2018 eruptions at Kīlauea Volcano in Hawaii resulted in about $800 million in damages but no loss of life. Credit: USGS

    Early in the morning on 17 May 2018, Hawaii’s Kīlauea Volcano unleashed a torrent of ash more than 3,000 meters into the sky. The explosion was just one noteworthy event in a months-long series of eruptions that destroyed more than 700 homes and caused $800 million in damage. Remarkably—thanks in large part to the relentless monitoring efforts of scientists at the Hawaiian Volcano Observatory (HVO)—no one died as a result of the destructive eruption sequence, which lasted into August.

    Across the country, in Washington, D.C., Senate lawmakers happened to meet that same day to vote on a topical piece of legislation: Senate bill 346 (S.346), the National Volcano Early Warning and Monitoring System Act. The Senate passed the bill by unanimous consent, marking a big step forward for a piece of legislation more than a decade in the making.

    The 1980 eruption of Mount St. Helens in Washington was the most destructive volcanic eruption in U.S. history, responsible for the deaths of 57 people and $1.1 billion in damage. Credit: Austin S. Post, USGS.

    The bill sought to strengthen existing volcano monitoring systems and unify them into a single system, called the National Volcano Early Warning System (NVEWS), to ensure that volcanoes nationwide are adequately monitored in a standardized way.

    After ultimately lacking the floor time in the House necessary for a vote before the end of 2018, the bill was reintroduced as part of a larger package of natural resources–related bills at the start of the new Congress, which convened in January. The John D. Dingell, Jr. Conservation, Management, and Recreation Act (S.47) contained elements of more than 100 previously introduced bills related to public lands, natural resources, and water. This bill quickly breezed through Congress and was signed into law by President Donald J. Trump on 12 March; it’s now Public Law No. 116-9.

    Although the bipartisan effort and the bill’s other contents, including an urgent reauthorization of the recently expired Land and Water Conservation Fund, captured the media’s attention, Section 5001, National Volcano Early Warning and Monitoring System, will have lasting effects on the nation’s volcano hazard awareness and preparation.

    Volcano Observatories

    Only five U.S. volcano observatories monitor the majority of U.S. volcanoes, with support from the U.S. Geological Survey’s (USGS) Volcano Hazards Program and independent universities and institutions. These observatories are the Alaska Volcano Observatory in Fairbanks; the California Volcano Observatory in Menlo Park; the Cascades Volcano Observatory in Vancouver, Wash.; HVO; and the Yellowstone Volcano Observatory in Yellowstone National Park, Wyo.

    Volcanologists at these observatories monitor localized earthquakes, ground movement, gas emissions, rock and water chemistry, and remote satellite data to predict when and where volcanic eruptions will happen, ideally providing enough time to alert the local populace to prepare accordingly.

    The USGS has identified 161 geologically active volcanoes in 12 U.S. states as well as in American Samoa and the Northern Mariana Islands. More than one third of these active volcanoes are classified by the USGS as having either “very high” or “high” threat on the basis of their hazard potential and proximity to nearby people and property.

    Many of these volcanoes have monitoring systems that are insufficient to provide reliable warnings of potential eruptive activity, whereas at others, the monitoring equipment is obsolete. A 2005 USGS assessment identified 58 volcanoes nationwide as being undermonitored.

    “Unlike many other natural disasters…volcanic eruptions can be predicted well in advance of their occurrence if adequate in-ground instrumentation is in place that allows earliest detection of unrest, providing the time needed to mitigate the worst of their effects,” said David Applegate, USGS associate director for natural hazards, in a statement before a House subcommittee hearing in November 2017.

    During the 2018 Kīlauea eruption, HVO, the oldest of the five observatories, closely monitored the volcano and issued routine safety warnings. However, many volcanoes lack the monitoring equipment or attention given to Kīlauea. Of the 18 volcanoes identified in the USGS report as “very high threat,” Kīlauea is one of only three classified as well monitored (the other two are Mount St. Helens in Washington and Long Valley Caldera in California).

    Public Law No. 116-9 aims to change that. In addition to creating the NVEWS, the law authorizes the creation of a national volcano watch office that will operate 24 hours a day, 7 days a week. The legislation also establishes an external grant system within NVEWS to support research in volcano monitoring science and technology.

    More than three of every four U.S. volcanoes that have erupted in the past 200 years are in Alaska (including Mount Redoubt, above). Credit: R. Clucas, USGS

    Volcanic Impacts

    Since 1980, there have been 120 eruptions and 52 episodes of notable volcanic unrest at 44 U.S. volcanoes, according to the USGS Volcano Hazards Program. The cataclysmic eruption of Mount St. Helens in 1980 was the most destructive, killing 57 people and causing $1.1 billion in damage.

    Although active volcanoes are concentrated in just a handful of U.S. states and territories, eruptions have the potential to pose significant security and economic threats across the nation. A 2017 report by the National Academies of Sciences, Engineering, and Medicine concluded that eruptions “can have devastating economic and social consequences, even at great distances from the volcano.”

    In 1989, for example, an eruption at Mount Redoubt in Alaska nearly caused a catastrophe. A plane en route from Amsterdam to Tokyo flew through a thick cloud of volcanic ash, causing all four engines to fail and forcing an emergency landing at Anchorage International Airport. More than 80,000 aircraft per year, carrying 30,000 passengers per day, fly over and downwind of Aleutian volcanoes on flights across the Pacific. The potential disruption to flight traffic as well as air quality issues from distant volcanoes poses serious health and economic risks for people across the United States.

    “People think they only have to deal with the hazards in their backyard, but volcanoes will come to you,” says Steve McNutt, a professor of volcano seismology at the University of South Florida in Tampa.

    National Volcano Early Warning and Monitoring System Act

    Passage of Public Law No. 116-9 authorizes funding for the implementation of the NVEWS. The bill recommends that Congress, during the annual appropriations process, appropriate $55 million over fiscal years 2019 through 2023 to the USGS to carry out the volcano monitoring duties prescribed in the bill.

    The bill was introduced by Sen. Lisa Murkowski (R-Alaska), first elected in 2002 and consistently the most steadfast champion of NVEWS legislation. Her home state of Alaska contains the most geologically active volcanoes in the country, and more than three of every four U.S. volcanoes that have erupted in the past 200 years are in Alaska. Often in concert with Alaska’s sole House representative, Don Young (R), Murkowski has introduced volcano monitoring legislation in nearly every congressional session since her election. Five bills over the past decade have stalled in committee without reaching the floor for a vote.

    “Our hazards legislation has become a higher priority because we realize that monitoring systems and networks are crucial to ensuring that Americans are informed of the hazards that we face,” Murkowski said in a speech at AGU’s Fall Meeting 2018 in Washington, D.C., last December. “They help us prepare and are crucial to protecting lives and property.”

    See the full article here .


    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 1:57 pm on April 23, 2019 Permalink | Reply
    Tags: "Atacama’s Past Rainfall Followed Pacific Sea Temperature", A Lack of Rain and Records, “It seems that ‘wetter’ episodes in the recent past in the Coastal Cordillera between Antofagasta and Arica line up with El Niño–like conditions”, “Our record covers only the first glacial-interglacial cycle”, “Whether this pattern is representative for all glacial­-interglacial times has to be tested with longer paleoclimate records.”, Eos, Paleoclimatology, The abundance of some planktonic diatoms further indicates the existence of an ephemeral water body” meaning the basin may have periodically flooded to become a temporary lake., The researchers are working to see whether the El Niño–like pattern extends further back.   

    From Eos: “Atacama’s Past Rainfall Followed Pacific Sea Temperature” 

    From AGU
    Eos news bloc

    From Eos

    Kimberly M. S. Cartier

    This is the first paleoclimate record of precipitation near Atacama’s hyperarid core and suggests that its moisture source is different from that of the Andes.

    Past rainfall in the Atacama Desert may have coincided with El Niño–like conditions. The team that discovered this conducted a deep-drilling follow-up expedition in 2017, seen here. Credit: Jan Voelkel

    Even the driest place on Earth, the Atacama Desert in Chile, still sees intermittent rainfall. In the past 215,000 years, these sporadic rainfall events may have coincided with elevated sea surface temperatures nearby that resemble El Niño conditions.

    “The Atacama Desert experienced several interspersed episodes of ‘wetter,’ still arid, conditions,” Benedikt Ritter, a paleoclimatologist at the University of Cologne in Germany, told Eos. “We are exploring…the mutual evolutionary relationship between climate, geomorphology, and biological evolution.”

    Ritter and his team published these results last month in Scientific Reports.

    In 2014, Benedikt Ritter and his team, seen here, used percussion drilling to extract a sediment core from the top 6 meters of a clay pan basin in the Atacama Desert. Credit: Damian Lopez

    A Lack of Rain and Records

    The hyperarid core of the Atacama Desert currently gets less than 2 millimeters of rainfall a year. Scientists don’t know when those conditions began or how often they were interrupted or for how long. The area’s sediment record for the most recent geologic period “appears like a white spot on the map,” Ritter said.

    Water runoff from the Altiplano, or Andean Plateau, to the east confuses sediment records in the hyperarid region, making it difficult to isolate local precipitation records.

    “The mostly barren landscape is almost undiscovered in terms of paleoclimate studies for the younger timescale,” Ritter said.

    Ritter and his team focused on a basin in the coastal mountain range, the Coastal Cordillera, that cuts through the hyperarid region. The basin’s location separates it from the surrounding mountain drainage networks, and its clay pan bottom helps it retain water. Sediment cores collected from this endorheic basin, the researchers hypothesized, should track past precipitation near the hyperarid core of the desert.

    Relatively Wet Periods

    The team used percussion drilling to collect a sediment core from the top 6.2 meters of the clay pan. The rock record spans the past 215,000 years and is the first paleoclimate record of the middle and upper Pleistocene for this region.

    The researchers looked at the size and composition of sediment grains as well as the abundance of fossilized microorganisms at different depths along the core. On the basis of these measures, they identified two significant wet times in the paleoclimate record: one around 200,000 years ago and a shorter period around 120,000 years ago.

    “Wet” is relative in the most arid place on the planet, Ritter said. “What we can tell, based on the sedimentological data, is that there was enough water available to transport coarse-grained sediment from the catchment into this pan.”

    Moreover, “the abundance of some planktonic diatoms further indicates the existence of an ephemeral water body,” meaning the basin may have periodically flooded to become a temporary lake.

    Atlantic Versus Pacific

    The researchers compared the timing of the basin’s wet periods with other nearby climate records and found something pretty surprising, Ritter said.

    “It seems that ‘wetter’ episodes in the recent past in the Coastal Cordillera, between Antofagasta and Arica, line up with El Niño–like conditions,” specifically, higher sea surface temperatures along the Chilean and Peruvian coasts, he explained.

    The researchers extracted a pilot core, part of which is seen here, from a basin in the coastal mountain range of the Atacama. Credit: Tibor Dunai

    “The pattern is totally inverse to the Andes,” said Marco Pfeiffer, a geoscientist at the Universidad de Chile in La Pintana who has studied the Atacama’s paleolakes and paleoclimate. “In this sense, [the study] is extremely novel and without a doubt a great contribution to the local paleoclimatology.” Pfeiffer was not involved with this research

    Because Ritter’s team collected this sediment core from a basin near to, but not within, the hyperarid zone, “there is still the question [of whether] these results could be extrapolated to iconic sites of the hyperarid core such as Yungay,” Pfeiffer cautioned.

    Drilling Down Deeper

    “Our record covers only the first glacial-interglacial cycle,” Ritter said. “Whether this pattern is representative for all glacial­-interglacial times has to be tested with longer paleoclimate records.”

    The researchers are working to see whether the El Niño–like pattern extends further back. In 2017, they conducted a follow-up expedition to this region and drilled deeper into the clay pan. Their new cores reach 8 times deeper than their first, Ritter said.

    “This new deep drilling sediment record extends the published reconstructed paleoclimate in this part of the Atacama Desert to even older times,” he said. The team plans to publish these records in the near future.

    See the full article here .


    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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