Stardust evidence points to planet collision

• Stardust evidence points to planet collision
  
  WASHINGTON, Sep 21, Masses of dust floating around a binary star system
  suggest that two Earth-like planets obliterated each other in a violent
  collision, U.S. researchers reported on Friday.
  
  "It's as if Earth and Venus collided with each other," Benjamin
  Zuckerman, an astronomer at the University of California Los Angeles, who
  worked on the study, said in a statement.
  
  "Astronomers have never seen anything like this before; apparently major,
  catastrophic, collisions can take place in a fully mature planetary system."
  
  Writing in the Astrophysical Journal, the team at UCLA, Tennessee State
  University and the California Institute of Technology said it spotted the dust
  orbiting a star known as BD +20 307, 300 light-years from Earth in the
  constellation Aries.
  
  A light-year is the distance light travels in a year, or about 6 trillion
  miles. So the observations are, in essence, looking back in time 300 years.
  
  "If any life was present on either planet, the massive collision would have
  wiped out everything in a matter of minutes: the ultimate extinction event,"
  said Gregory Henry of Tennessee State University.
  
  BD +20 307 appears to be composed of two stars, both very similar in mass,
  temperature and size to the Earth's sun. They spin about their common center
  of mass every 3 1/2 days or so.
  
  "The planetary collision in BD +20 307 was not observed directly but, rather,
  was inferred from the extraordinary quantity of dust particles that orbit the
  binary pair at about the same distance as Earth and Venus are from our sun,"
  Henry said.
  
  "If this dust does indeed point to the presence of terrestrial planets,
  then this represents the first known example of planets of any mass in orbit
  around a close binary star."
  
  In July 2005, the team reported it had spotted the system, then believed to
  consist of a single star. It was surrounded by more warm orbiting dust than
  any other sun-like star known to astronomers.
  
  "This poses two very interesting questions," said Tennessee State's
  Francis Fekel. "How do planetary orbits become destabilized in such an old,
  mature system? Could such a collision happen in our own solar system?"