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Thread: Astronomy

  1. #1216
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    This is yet another probe that I knew nothing about: NASA's Messenger orbiting the planet Mercury.

  2. #1217
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    I did indeed know about this, just not got round to searching for the internet link:

    https://astronomynow.com/2017/10/05/...to-early-2019/

  3. #1218
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    Quote Originally Posted by Dreamwoven View Post
    This is from the notes I still get from my subscription to the Society for Popular Astronomy (which is no longer active).

    This report suggests there is surface ice on Mercury, if confirmed this would be astonishing.

    MERCURY'S POLES ICIER THAN WAS THOUGHT
    Brown University

    The scorching-hot surface of Mercury may seem an unlikely place to
    find ice, but research over the past 30 years has indicated that water
    is frozen there, hidden away on crater floors that are permanently
    shadowed from the Sun's blistering rays. Now, a new study suggests
    that there could be much more ice on Mercury's surface than previously
    thought. The study adds three new members to the list of craters
    near Mercury's north pole that appear to harbour large surface ice
    deposits. But in addition to those large deposits, the research also
    shows evidence that smaller-scale deposits are scattered around
    Mercury's north pole, both inside craters and in permanently shadowed
    areas between craters. Those deposits may be small, but they could
    add up to a lot of previously-unaccounted-for ice. The idea that
    Mercury might have frozen water emerged in the 1990s, when Earth-based
    radars detected highly reflective regions inside several craters near
    Mercury's poles. The planet's axis does not have much tilt, so its
    poles get little direct sunlight, and the floors of some craters get
    no direct sunlight at all. Without an atmosphere to hold in any heat
    from surrounding surfaces, temperatures in those eternal shadows have
    been calculated to be plenty low enough for water ice to be stable.
    That raised the possibility that the 'radar-bright' regions could be
    ice. That idea got a boost after NASA's MESSENGER probe entered an
    orbit around Mercury in 2011. The spacecraft detected neutron signals
    from the planet's north pole that were consistent with water ice.
    These recent finds suggests that there probably exist other water freezing physical laws, than the ones one learns at school.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  4. #1219
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    Quote Originally Posted by Dreamwoven View Post
    I did indeed know about this, just not got round to searching for the internet link:

    https://astronomynow.com/2017/10/05/...to-early-2019/
    With so much involved I think they are right in taking the necessary time.

    By the way, French Guiana is one of our northern neighbors:

    https://www.lonelyplanet.com/maps/so...french-guiana/
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  5. #1220
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    Quote Originally Posted by Danik 2016 View Post
    These recent finds suggests that there probably exist other water freezing physical laws, than the ones one learns at school.
    Maybe!

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  7. #1222
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    A very interesting theory. Maybe England is on the way to something there.

    "Self-organization in physical systems
    When energy is applied to a system, the laws of physics dictate how that energy dissipates. If an external heat source is applied to that system, it will dissipate and reach thermal equilibrium with its surroundings, like a cooling cup of coffee left on a desk. Entropy, or the amount of disorder in the system, will increase as heat dissipates. But some physical systems may be sufficiently out of equilibrium that they "self-organize" to make best use of an external energy source, triggering interesting self-sustaining chemical reactions that prevent the system from reaching thermodynamic equilibrium and thus maintaining an out-of-equilibrium state, England speculates. (It's as if that cup of coffee spontaneously produces a chemical reaction that sustains a hotspot in the center of the fluid, preventing the coffee from cooling to an equilibrium state.) He calls this situation "dissipation-driven adaptation" and this mechanism is what drives life-like qualities in Englandís otherwise lifeless physical system.

    A key life-like behavior is self-replication, or (from a biological viewpoint) reproduction. This is the basis for all life: It starts simple, replicates, becomes more complex and replicates again. It just so happens that self-replication is also a very efficient way of dissipating heat and increasing entropy in that system."
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  8. #1223
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    I've lost the drift of this logic, sorry...

  9. #1224
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    One of the features of self-organization is the ability to be goal directed. That system has goals and purposes. It makes choices. Machines don't do that.

    To say that life may be a "fluke" is an admission of defeat, so England is at least trying to find an explanation which is what science should be doing. Even if the explanation comes down to some conscious choice at some level, that is a better explanation than to say it happened by chance. However, I don't think England wants there to be a conscious choice at all involved.

  10. #1225
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    Quote Originally Posted by Dreamwoven View Post
    I've lost the drift of this logic, sorry...
    No matter, I only cited from the article.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  11. #1226
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    "New research helps solve galactic murders

    Why do galaxies stop making stars?

    The stars and galaxies we see in the night sky appear unchanging, but they all undergo dynamic processes, evolving throughout their lifetimes. While scientists donít know exactly what mixture of cosmic events leads to the termination of star formation across galaxies, they have found several key players.

    A leading cause of galaxy death is ram-pressure stripping. Drawn in by gravitation attraction, galaxies tend to group together in clusters. The space between galaxies in these clusters is filled with hot gas, and as the galaxies move through the cluster, the gas acts as a headwind. When the wind is strong enough, it can remove loose gas within the galaxy itself ó gas that would typically be used to create new stars."

    http://www.astronomy.com/news/2017/1...lactic-murders
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  12. #1227
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    The birth and death of stars is especially interesting.

  13. #1228
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    Notes from the Society for Popular Astronomy:

    NANOSAT FLEET PROPOSED TO VISIT 300 ASTEROIDS
    European Planetary Science Congress

    A fleet of tiny spacecraft could visit over 300 asteroids in just
    over three years, according to a mission study led by the Finnish
    Meteorological Institute. The Asteroid Touring Nanosat Fleet concept
    comprises 50 spacecraft propelled by innovative electric solar wind
    sails (E-sails) and equipped with instruments to take images and
    collect spectroscopic data on the composition of the asteroids. Each
    nanosat would visit six or seven asteroids before returning to Earth
    to deliver the data. In the mission scenario, the nanosats fly by
    their target asteroids at a range of around 1000 kilometres. Each
    nanosat carries a 4-centimetre telescope capable of imaging the
    surface of asteroids with a resolution of 100 metres or better. An
    infrared spectrometer analyses spectral signatures in light reflected
    or emitted by the asteroid to determine its mineralogy. The instru-
    ments can be pointed at the target by the use of two internal reaction
    wheels inside the nanosats. E-sails make use of the solar wind -- a
    stream of electrically charged particles emitted from the Sun -- to
    generate efficient propulsion without the need for any propellent.
    Thrust is generated by the slow rotation of a tether, attached at one
    end to a main spacecraft carrying an electron emitter and a high-
    voltage source and at the other to a small remote unit. The spinning
    tether completes a rotation in about 50 minutes, tracing out a broad,
    shallow cone around a centre of mass close to the main spacecraft.
    By altering its orientation in relation to the solar wind, the nanosat
    can change thrust and direction

  14. #1229
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    I only wonder what all these mega space projects are going to cost.
    "You can always find something better than death."
    Jacob and Wilhelm Grimm, The Bremen Town Musicians

  15. #1230
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    One good reason for co-operation, though I notice that the idea of collaborating with Russia has been dropped. I guess Trump has taken too much flack for that idea, which is a real pity.

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