Loading ...
Sorry, an error occurred while loading the content.
 

Hominid Ancestors Saw Nearby Supernova As Second Sun

Expand Messages
  • Stig Agermose
    Source: http://news.bbc.co.uk/low/english/sci/tech/newsid_388000/388291.stm Stig *** BBC News Online: Sci/Tech Wednesday, July 7, 1999 Published at 16:11 GMT
    Message 1 of 1 , Jul 9, 1999
      Source:

      http://news.bbc.co.uk/low/english/sci/tech/newsid_388000/388291.stm

      Stig

      ***

      BBC News Online: Sci/Tech

      Wednesday, July 7, 1999 Published at 16:11 GMT 17:11 UK

      'Star material' recovered from South Pacific

      By BBC News Online Science Editor Dr David Whitehouse

      **

      Atoms that have travelled to Earth from a distant, exploded star have been
      discovered for the first time, scientists claim.

      The radioactive iron-60 atoms were recovered from ocean sediment on a
      seafloor site in the South Pacific. German astronomers believe they came to
      Earth from a supernova, one of nature's grandest spectacles.

      When a single star explodes, it can outshine an entire galaxy of suns for
      several days. It becomes brighter than a hundred thousand million stars and
      light from the explosion can still be detected on Earth even if the
      explosion is right on the edge of the known Universe.

      Scientists are seeing supernovae all the time - they have become useful
      tools for measuring the size of the Universe. On one occasion, rare and
      ghostly particles called neutrinos have even been detected from a supernova.

      However, finding atoms that have been ejected in the explosion is a little
      controversial. In a sense, all the atoms on Earth, with the exception of
      hydrogen and helium, have been processed through, or created in, supernovae
      many millions - even billions - of years ago. Without supernovae there
      would be no heavier elements in the Universe.


      Close event


      But the German team, from Technische Universit�t M�nchen and the Max-Plank
      Institute, say the iron-60 atoms were deposited on Earth relatively
      recently - only a few million years ago.

      Several sediment layers in the South Pacific were dated, and the samples
      looked at with a device called an accelerator mass spectroscope that can
      detect faint traces of iron isotopes.

      Because Iron-60 decays by half every 1.5 million years, the levels detected
      in the sample, and the lack of terrestrial sources of the isotope point to
      a relatively nearby and recent supernova as its source, the researchers say.

      They think the supernova may have been just 90-180 light years from the
      Earth.

      If this is true, our hominid ancestors must have seen it as the brightest
      thing in the sky after the Sun. If the supernova had been any closer, it
      might even have affected the Earth's climate, possibly causing the
      extinction of species and damage to the land and upper layers of the oceans.


      Relevant Stories:

      *Universe is 12 billion years old (26 May 99�|�Sci/Tech)
      *When a star explodes (08 Feb 99�|�Sci/Tech)
      *Explosion on the edge of space (18 Dec 98�|�Sci/Tech)


      Internet Links:

      *Supernova Cosmology Project


      The BBC is not responsible for the content of external internet sites.

    Your message has been successfully submitted and would be delivered to recipients shortly.