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  • richardmitnick 7:58 am on July 31, 2014 Permalink | Reply
    Tags: , , Atmospherics, , ,   

    From ESA: “Lifetime of Gravity Measurements Heralds New Beginning” 

    ESASpaceForEuropeBanner
    European Space Agency

    30 July 2014
    No Writer Credit

    Although ESA’s GOCE satellite is no more, all of the measurements it gathered during its life skirting the fringes our atmosphere, including the very last as it drifted slowly back to Earth, have been drawn together to offer new opportunities for science.

    ESA GOCE Spacecraft
    ESA/GOCE

    Carrying the first 3D gravity sensor in space, this state-of-the-art satellite measured Earth’s gravity with unprecedented accuracy.

    GOCE’s four years in orbit resulted in a series of four gravity models, each more accurate than the last. These models have been used to generate corresponding ‘geoids’ – the surface of a global ocean moulded by gravity alone.

    Shaped by differences in gravity, the geoid is a crucial reference for understanding ocean circulation, sea-level change and ice dynamics.

    2011
    2011 GOCE geoid

    From a mission that just keeps giving, a fifth model has now been produced. It incorporates data collected throughout the satellite’s 42-month operational life.

    The previous geoid, released in March 2013, was based on 27 months of measurements.

    The satellite was designed to orbit at an extremely low altitude of 255 km to gain the best possible gravity measurements. At the end of 2012, low fuel consumption allowed operators to extend its life and start to lower the satellite a further 31 km for even more accurate measurements. This was at the very limit of its capability but maximised the return for science.

    After more than doubling its planned life in orbit, the satellite ran out of fuel and drifted back into the atmosphere in November 2013.
    GOCE reenters atmosphere

    The fifth gravity model and geoid, which ESA has recently made available, includes these final precious measurements, right up until the satellite finally stopped working and ironically succumbed to the force it was designed to measure.

    Although the satellite is no longer in orbit, scientists now have the best possible information to hand about Earth’s gravity, effectively a new beginning for the mission.

    GOCE has already shed new light on different aspects of Earth and surpassed its original scope in a number of ways.

    It is being used to understand how oceans carry huge quantities of heat around the planet and to develop a global height reference system.

    It has provided information about atmospheric density and winds, mapped the boundary between Earth’s crust and upper mantle, and used to understand what is going on in these layers far below our feet.

    layers
    Moho and lithosphere

    And its achievements include mapping a scar in Earth’s gravity caused by the 2011 Japanese earthquake.

    The ultimate geoid model and gravity data will be used for years to come for a deeper understanding of Earth.

    scar
    Gravity scar over Japan

    ESA’s GOCE Mission Manager, Rune Floberghagen, said, “We are very happy with the results of the final, super-low altitude phase of our mission.

    “In fact, efforts made by the mission team and by scientists to secure flight operations at these extreme altitudes and to process the data have resulted in a doubling of the information content and a very significant increase in spatial resolution.

    “Indeed, our new ‘Release 5 solutions’ go well beyond the ambitious objectives we had when the GOCE project started.

    “Scientists worldwide now have a satellite-based gravity field model at hand that will remain the de facto standard for many years to come.”

    See the full article here.

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 4:28 pm on July 17, 2014 Permalink | Reply
    Tags: , Atmospherics, , ,   

    From Livermore lab: “Peering into giant planets from in and out of this world “ 


    Lawrence Livermore National Laboratory

    07/17/2014
    Anne M Stark, LLNL, (925) 422-9799, stark8@llnl.gov

    Lawrence Livermore scientists for the first time have experimentally re-created the conditions that exist deep inside giant planets, such as Jupiter, Uranus and many of the planets recently discovered outside our solar system.

    point
    The interior of the target chamber at the National Ignition Facility at Lawrence Livermore National Laboratory. The object entering from the left is the target positioner, on which a millimeter-scale target is mounted. Researchers recently used NIF to study the interior state of giant planets. Image by Damien Jemison/LLNL

    Researchers can now re-create and accurately measure material properties that control how these planets evolve over time, information essential for understanding how these massive objects form. This study focused on carbon, the fourth most abundant element in the cosmos (after hydrogen, helium and oxygen), which has an important role in many types of planets within and outside our solar system. The research appears in the July 17 edition of the journal, Nature.

    Using the largest laser in the world, the National Ignition Facility at Lawrence Livermore National Laboratory, teams from the Laboratory, University of California, Berkeley and Princeton University squeezed samples to 50 million times Earth’s atmospheric pressure, which is comparable to the pressures at the center of Jupiter and Saturn. Of the 192 lasers at NIF, the team used 176 with exquisitely shaped energy versus time to produce a pressure wave that compressed the material for a short period of time. The sample — diamond — is vaporized in less than 10 billionths of a second.

    Though diamond is the least compressible material known, the researchers were able to compress it to an unprecedented density greater than lead at ambient conditions.

    “The experimental techniques developed here provide a new capability to experimentally reproduce pressure-temperature conditions deep in planetary interiors,” said Ray Smith, LLNL physicist and lead author of the paper.

    Such pressures have been reached before, but only with shock waves that also create high temperatures — hundreds of thousands of degrees or more — that are not realistic for planetary interiors. The technical challenge was keeping temperatures low enough to be relevant to planets. The problem is similar to moving a plow slowly enough to push sand forward without building it up in height. This was accomplished by carefully tuning the rate at which the laser intensity changes with time.

    “This new ability to explore matter at atomic scale pressures, where extrapolations of earlier shock and static data become unreliable, provides new constraints for dense matter theories and planet evolution models,” said Rip Collins, another Lawrence Livermore physicist on the team.

    The data described in this work are among the first tests for predictions made in the early days of quantum mechanics, more than 80 years ago, which are routinely used to describe matter at the center of planets and stars. While agreement between these new data and theory are good, there are important differences discovered, suggesting potential hidden treasures in the properties of diamond compressed to such extremes. Future experiments on NIF are focused on further unlocking these mysteries.

    See the full article here.

    Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security
    Administration
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    NNSA

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  • richardmitnick 7:53 am on May 16, 2014 Permalink | Reply
    Tags: Atmospherics, CERN CLOUD   

    From CERN: “CERN experiment sheds new light on cloud formation” 

    CERN New Masthead
    CERN

    16 May 2014
    Dan Noyes

    In a paper published in the journal Science
    today, CERN’s CLOUD experiment has shown that biogenic vapours emitted by trees and oxidised in the atmosphere have a significant impact on the formation of clouds, thus helping to cool the planet. These biogenic aerosols are what give forests seen from afar their characteristic blue haze. The CLOUD study shows that the oxidised biogenic vapours bind with sulphuric acid to form embryonic particles which can then grow to become the seeds on which cloud droplets can form. This result follows previous measurements from CLOUD showing that sulphuric acid alone could not form new particles in the atmosphere as had been previously assumed.

    CERN CLOUD New
    CERN CLOUD

    “This is a very important result, since it identifies a key ingredient responsible for formation of new aerosol particles over a large part of the atmosphere – and aerosols and their impact on clouds have been identified by the Intergovernmental Panel on Climate Change as the largest source of uncertainty in current climate models.” Jasper Kirkby, CLOUD experiment

    Cloud droplets form on aerosol particles that can either be directly emitted, such as evaporated sea spray, or else form through a process known as nucleation, in which trace atmospheric vapours cluster together to form new particles that may grow to become cloud seeds. Around half of all cloud seeds are thought to originate from nucleated particles, but the process of nucleation is poorly understood.

    The CLOUD chamber has achieved much lower concentrations of contaminants than previous experiments, allowing nucleation to be measured in the laboratory under precisely controlled atmospheric conditions. The experiment has several unique aspects, including the ability to control the “cosmic ray” beam intensity from the CERN PS, the capability to suppress ions completely by means of a strong electric clearing-field, precise adjustment of “sunlight” from a UV fibre-optic system, and highly-stable operation at any temperature in the atmosphere.

    Sulphuric acid is thought to play a key role, but previous CLOUD experiments have shown that, on its own, sulphuric acid has a much smaller effect than had been assumed. Sulphuric acid in the atmosphere originates from sulphur dioxide, for which fossil fuels are the predominant source. The new result shows that oxidised biogenic vapours derived from alpha-pinene emitted by trees rapidly form new particles with sulphuric acid. Ions produced in the atmosphere by galactic cosmic rays are found to enhance the formation rate of these particles significantly, but only when the concentrations of sulphuric acid and oxidised organic vapours are relatively low. The CLOUD paper includes global modelling studies which show how this new process can account for the observed seasonal variations in atmospheric aerosol particles, which result from higher global tree emissions in the northern hemisphere summer.

    cloud
    Jasper Kirkby The CLOUD experimental chamber seen in October 2013 (Image: CERN, Jasper Kirkby)

    “The reason why it has taken so long to understand the vapours responsible for new particle formation in the atmosphere is that they are present in minute amounts near one molecule per trillion air molecules”, explains Jasper Kirkby. “Reaching this level of cleanliness and control in a laboratory experiment is at the limit of current technology, and CERN know-how has been crucial for CLOUD being the first experiment to achieve this performance.”

    Biogenic vapours join another class of trace vapours, known as amines, that have previously been shown by CLOUD to cluster with sulphuric acid to produce new aerosol particles in the atmosphere. Amines, however, are only found close to their primary sources such as animal husbandry, whereas alpha-pinene is ubiquitous over landmasses. This latest result from CLOUD could therefore explain a large fraction of the birth of cloud seeds in the lower atmosphere around the world. It shows that sulphuric acid aerosols do indeed have a significant influence on the formation of clouds, but they need the help of trees.

    See the full article here.

    Meet CERN in a variety of places:

    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New
    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New

    LHC

    CERN LHC New

    LHC particles

    Quantum Diaries


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