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Fwd = "Northern and southern auroras are mirror images of each other"

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  • Frits Westra
    Forwarded by: fwestra@hetnet.nl (Frits Westra) http://www.nzherald.co.nz/worldnews/../storydisplay.cfm?storyID=225933&thesection=news&thesubsection=world
    Message 1 of 1 , Nov 1, 2001
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      Forwarded by: fwestra@... (Frits Westra)
      http://www.nzherald.co.nz/worldnews/../storydisplay.cfm?storyID=225933&thesection=news&thesubsection=world
      Original Date: Thu, 1 Nov 2001 11:02:35 -0800

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      The picture of the auroras confirms a two-century-old theory.

      01.11.2001

      Scientists studying the effects of solar radiation have confirmed a
      two-century-old theory - the northern and southern auroras are mirror
      images of each other.

      Pictures taken by Nasa's polar satellite, which was launched in
      February 1996 to study the effects solar energy has on the Earth's
      atmosphere, prove the theory.

      The northern lights - the aurora borealis - and the southern lights -
      the aurora australis - are giant magnetic storms which usually occur
      during the autumn and spring equinoxes caused by sudden gusts in the
      solar wind.

      The northern lights have been pondered for millenniums, but it was
      only in September 1770 that the lights in both hemispheres were
      recorded at the same time.

      In that month, Captain James Cook saw lights in the south and Chinese
      astronomers spotted similar lights in the north.

      Scientists have since studied the auroras over both poles.

      But because images were taken at different times they did not allow
      comparison.

      One of the designers of the camera that took the satellite images, Dr
      John Sigwarth, said they showed for the first time that auroras were
      giant mirror images.

      Early analysis suggested they matched on a broad scale, but some of
      their fine features differed.

      The gust that caused this display erupted from the enormous sunspot
      9682 on October 20 and sped to Earth at about 1.6 million kilometres
      an hour.

      Witnesses in North America said the night-time show was spectacular. .

      Meanwhile, Australia and the Pacific could experience a dazzling
      hailstorm of shooting stars this month as the Earth hits a series of
      dense meteor trails.

      Experts believe that at the storm's peak more than 20,000 meteors an
      hour may be seen by observers in the western Pacific, eastern Asia and
      Australia, but not New Zealand as the display will occur during our
      daylight hours.

      But if the predictions are correct, the show will be awesome - a
      firestorm in the heavens the like of which has not been seen for 35
      years.

      The Leonid meteor shower occurs each November when the Earth ploughs
      through trails of tiny dust particles left by the comet Tempel-Tuttle
      as it sweeps through the inner solar system every 33 years.

      Sometimes thick trails are hit, resulting in a spectacular meteor
      storm as the particles - most no bigger than a grain of sand - burn up
      in the atmosphere at 240,000 km/h.

      This year's Leonid shower is expected to be so big it could threaten
      orbiting satellites. Astronomers believe at least one satellite could
      be knocked out between November 17 and 19, at the height of the meteor
      shower.

      Each time Tempel-Tuttle returns, it leaves a trail of shed comet
      debris in a slightly different position.

      �Copyright 2001, New Zealand Herald

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