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Rings around the Earth??

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  • David
    Yep...and they could ve been responsible for climate change. http://www.sandia.gov/news-center/news-releases/20 02/earth-sci-fossil-fuel/ringworld.html Sandia
    Message 1 of 5 , Sep 12 10:52 AM
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      Yep...and they could've been responsible for climate change.

      http://www.sandia.gov/news-center/news-releases/20
      02/earth-sci-fossil-fuel/ringworld.html

      Sandia National Laboratories
      FOR IMMEDIATE RELEASE
      September 11, 2002

      Rings around the Earth: A clue to climate change?

      ALBUQUERQUE, N.M. - Rings around the earth?

      While most of us know about rings around Saturn and Jupiter, some
      scientists believe there once were rings of rock debris around our own
      planet. Two scientists - Peter J. Fawcett, of the University of New
      Mexico, and Mark B.E. Boslough, of the U.S. Department of Energy's
      Sandia National Laboratories - have suggested that a geologically
      "recent" collision (about 35 million years ago) may have caused such a
      temporary debris ring.

      The two also suggest that such temporary rings - lasting from 100,000
      to a few millions of years - may explain some patterns of climate
      change observed in the earth's geological record. These conclusions
      are spelled out in an article in the Journal of Geophysical Research,
      Atmospheres, August 16 edition.

      Lore of the Rings

      "One way to get a ring," says Sandia's Boslough, "is with an impact."
      There is a growing body of evidence showing that the earth has been
      subjected to numerous impacts by comets and asteroids throughout its
      history. Among these impacts are the Meteor Crater, in Arizona, the
      buried Chixulub crater, in the Yucatan Peninsula of Mexico, and a
      chain of at least five craters spread across several continents.

      Several studies, both theoretical and with laboratory data, suggest
      that some large impacts are capable of ejecting material into space in
      the form of debris rings, if the mechanics of the impact meet certain
      requirements. The authors conclude that the mostly likely scenario for
      ring creation is a low-angle impact by a large asteroid. Some earth
      materials and melted meteoric debris, called "tektites" would form the
      ring materials.

      Boslough describes an impact where the collision object ricochets back
      into the atmosphere. The ricochet becomes part of an expanding vapor
      cloud, setting up an interaction that allows some of the debris to
      attain orbit velocity. The orbiting debris will collapse into a single
      plane by the same mechanics that led to the rings of Saturn and other
      planets, Boslough explains. Such a ring would most likely form near
      the equator, because of the dynamics involved with the moon and the
      earth's equatorial bulge.

      Speculation on climates past

      The effects of the larger impact events on earth's environment and
      climate have been the subjects of much speculation and research over
      the past two decades. "Clearly, large impacts have affected the
      evolution of the earth, life on it and its atmospheric environment,"
      says Fawcett.

      Much of the work has focused on the Cretaceous-Tertiary (K-T) boundary
      event, which marked a mass extinction and the end of the age of the
      dinosaurs about 65 million years ago. A number of these studies
      suggest an impact resulting in the suspension of a layer of dust in
      the upper atmosphere blocking sunlight and cooling the earth. The two
      researchers asked could other impacts result in different
      atmosphere-altering phenomena?

      An equatorial ring would cast a shadow primarily in the tropics, as it
      does for Saturn. Depending on location, surface area, and darkness of
      the ring shadow, the amount of incoming solar warmth, or insolation,
      could be significantly altered, the two authors conclude. To test
      their theory, the two assumed an opaque ring, like Saturn's B-ring,
      scaled to earth-size and tested global climate affects using a climate
      model.

      The model selected and modified for the simulation was developed by
      the National Center for Atmospheric Research (NCAR.) The Center's
      "Genesis" climate model includes atmospheric circulation information
      and layers of vegetation, soil, snow, sea temperature and land ice
      data. The goals of the internally funded project were for Sandia to
      adapt a popular climate code to run on distributed-memory parallel
      computers and to establish relationships with the climate change
      research community, Boslough explained. The Labs made use of its
      Sandia University Research Program to fund Fawcett's efforts to
      analyze the data from the adapted code.

      A Ring World

      "The equatorial debris ring has a profound effect on climate, because
      it reflects a significant fraction of tropical insolation back to
      space before it can interact with the atmosphere," the authors
      conclude. Surface and atmospheric temperatures, changes in temperature
      ranges from equator to poles, circulation patterns and the rain and
      snow cycles were all impacted by the ring, the model shows.

      The two scientists looked at changes shown in the model to predict
      changes that might be found in the earth's geologic record as a way to
      test their work. In addition to the K-T boundary event, they looked at
      a more recent impacts and a much older one.

      The most recent event - about 35 million years ago - is identified by
      an iridium layer (often associated with meteors) and two pronounced
      mico-tektite fields, where these melted meteor-related materials have
      been found and dated. Climatic records from sedimentary materials just
      above the iridium/micro-tektite interval indicate a 100,000-year
      cooling interval. Orbiting debris in a ring, casting its shadow in the
      subtropics could have sustained such a cooling trend, the authors
      suggest.

      The K-T boundary impact - about 65 million years ago - was much larger
      than the more recent impact and had a much larger immediate effect on
      the environment as measured by extinctions and atmospheric changes.
      But there were no long-term effects on the climate, leading the
      authors to conclude the event probably did not generate a debris ring.

      Snowball Earth

      Another interesting aspect of the modeling work is its implications
      for the so-called "Snowball Earth" theory. This theory holds that the
      earth was completely frozen over at the surface as many as four times
      in the neoproterozoic period - 750 to 580 million years ago. While
      much remains to be learned about the geologic evidence for this
      theory, "an opaque ring could have acted as the trigger to at least
      one episode of global glaciation," the two researchers say. This would
      address one difficult question for the theorists: how did earth come
      to be frozen?
    • kirk
      Snowball Earth Another interesting aspect of the modeling work is its implications for the so-called Snowball Earth theory. This theory holds that the earth
      Message 2 of 5 , Sep 12 9:07 PM
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        Snowball Earth

        Another interesting aspect of the modeling work is its implications
        for the so-called "Snowball Earth" theory. This theory holds that the
        earth was completely frozen over at the surface as many as four times
        in the neoproterozoic period - 750 to 580 million years ago. While
        much remains to be learned about the geologic evidence for this
        theory, "an opaque ring could have acted as the trigger to at least
        one episode of global glaciation," the two researchers say. This would
        address one difficult question for the theorists: how did earth come
        to be frozen?


        If the earth was completely frozen where did the life survive? Land plants
        and trees don't grow well in the ocean.
        Land animals either.

        Kirk
      • David
        ... plants ... Beats the heck outta me! I m assuming they don t mean that it was literally a solid impenetrable sheet of ice.
        Message 3 of 5 , Sep 12 10:08 PM
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          > If the earth was completely frozen where did the life survive? Land
          plants
          > and trees don't grow well in the ocean.
          > Land animals either.
          >
          > Kirk

          Beats the heck outta me! I'm assuming they don't mean that it was
          literally a solid impenetrable sheet of ice.
        • foryeshua1@juno.com
          I would reject the idea that the earth could have been frozen over its whole surface. If the SE causes the ice to form as I believe it does, it will only
          Message 4 of 5 , Sep 13 10:01 AM
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            I would reject the idea that the earth could have been frozen over its
            whole surface. If the SE causes the ice to form as I believe it does, it
            will only freeze two spots at the same time. The North and South poles.
            Walter
            On Thu, 12 Sep 2002 22:07:24 -0600 "kirk" <kirk@...> writes:
            >
            > Snowball Earth
            >
            > Another interesting aspect of the modeling work is its implications
            > for the so-called "Snowball Earth" theory. This theory holds that
            > the
            > earth was completely frozen over at the surface as many as four
            > times
            > in the neoproterozoic period - 750 to 580 million years ago. While
            > much remains to be learned about the geologic evidence for this
            > theory, "an opaque ring could have acted as the trigger to at least
            > one episode of global glaciation," the two researchers say. This
            > would
            > address one difficult question for the theorists: how did earth
            > come
            > to be frozen?
            >
            >
            > If the earth was completely frozen where did the life survive? Land
            > plants
            > and trees don't grow well in the ocean.
            > Land animals either.
            >
            > Kirk
            >
            >
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          • David
            ... does, it ... I must admit that I had heard of the snowball earth theory before. It does sound a bit hard to believe.
            Message 5 of 5 , Sep 13 8:30 PM
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              --- In methanehydrateclub@y..., foryeshua1@j... wrote:
              > I would reject the idea that the earth could have been frozen over its
              > whole surface. If the SE causes the ice to form as I believe it
              does, it
              > will only freeze two spots at the same time. The North and South poles.
              > Walter
              > On Thu, 12 Sep 2002 22:07:24 -0600 "kirk" <kirk@3...> writes:

              I must admit that I had heard of the "snowball earth" theory before.
              It does sound a bit hard to believe.
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