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A different 'Big bang' may have saved Earth

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  • derhexer@aol.com
    URL to an article that appeared in USA Today http://www.usatoday.com/tech/science/space/2005-01-26-big-bang_x.htm First few paragraphs A different Big Bang
    Message 1 of 1 , Jan 29, 2005
      URL to an article that appeared in USA Today
      http://www.usatoday.com/tech/science/space/2005-01-26-big-bang_x.htm

      First few paragraphs


      "A different 'Big Bang' may have saved Earth

      By Dan Vergano, USA TODAY
      SAN DIEGO — An exploding star in our solar system's infancy may have saved
      Earth from extinction.

      Astronomers studying the planet-forming disks of dust that orbit young,
      distant stars are hoping to solve the mystery of our own solar system's youth. Why
      is our system so different in form and function from others they can see?

      It's a difference that may have saved Earth, because the scientists suspect
      that Jupiter and Saturn would have collided with the planet — or slung it out
      of the solar system like a slingshot — if the disk surrounding our young sun
      hadn't been so damaged.

      These "protoplanetary" disks were a hot topic at a recent meeting of the
      American Astronomical Society. "Something very bad happened to our solar system's
      disk in its early years," says Steve Desch of Arizona State University in
      Tempe.

      An exploding star, or supernova, likely occurred within a light-year — about
      5.9 trillion miles — of our sun in its infancy, he argues. (The closest star
      to our solar system now, Proxima Centauri, is about 4 light-years away).

      First spotted by an infrared satellite in the 1980s, the disks are the
      swirling leftovers of nebulas, pockets of gas within galaxies that spawn new stars.

      Some of this dust compresses into planets, more of which have been discovered
      orbiting nearby stars during the past decade. A presentation at the meeting
      about a Hubble Space Telescope survey of 25 nearby stars, all youngsters less
      than 10 million years old, provides evidence that dust disks congeal into more
      compact bodies over only a few million years.

      Over time, the rest of the dust is blown away by solar wind or other effects.
      What is left behind is a solar system like our own.

      Glances at nearby disks, and some leftover clues, are telling researchers how
      things began for our sun. And it looks like we may inhabit a solar system
      that's something of a runt because of the damage from an exploding star.






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