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Fwd: [UASR]> Parallel double meteor trails

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  • Frits Westra
    ^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~^~ [U A S R] UFOs-, ALIENs-, SPACE- RESEARCH MAILING LIST
    Message 1 of 1 , May 30, 2004
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      [U A S R]> UFOs-, ALIENs-, SPACE- RESEARCH MAILING LIST <[U A S R]
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      Forwarding permission was given by William R. Corliss.

      Science Frontiers, No. 153, May-Jun, 2004, pp. 1 & 2
      < http://www.science-frontiers.com >


      ASTRONOMY

      Parallel double meteor trails

      Meteor-watchers, of which there are quite a few, report fairly often
      observations of doubled meteor trails shining bright in the night sky.
      Like aircraft contrails, these neatly parallel streaks are eventually
      twisted and contorted by the winds of the upper atmosphere. The
      Leonids are famous for producing a loose tapestry of bright trails
      containing a few doublets.

      Astronomers doubt that the pairs of parallel trails are traced out by
      split meteors plunging side-by-side through the increasingly dense air.
      If meteor break-up were the cause, they would also expect to see a few
      triple or even higher-order parallel trails. They don't

      The preferred explanation of double trails assumes that a single meteor
      leaves a hollow tube of glowing debris. A "limb effect" makes the tube's
      edges brighter than its center.

      In *Geophysical Research Letters*, M.C. Kelley et al assert that the
      brightness contrast between the edges of the putative tube and its center
      is too great for the limb-effect explanation. Their solution:

      ...one train is due to excited gas from the meteor and the other,
      lying below the first, comes from dust sedimenting under gravity.

      (Ball, Philip; "Parallel Lines," *Nature*, 426:784, 2003)

      Comment. If the components of the twin trails have different physical
      causes, wouldn't the parallelism disappear more quickly than is observed---
      especially in long sinuous double trails? In other words, the upper gas
      trail would be affected very differently than the lower dust trail---and
      quickly.


      [Science Frontiers is a bimonthly collection of digests of scientific
      anomalies in the current literature. Published by the Sourcebook Project,
      P.O. Box 107, Glen Arm, MD 21057. Annual subscription: $8.00.]
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