What happened to the Neanderthals?

   It used to be that carbon 14 dating of Neanderthal sites and modern human sites showed a 20,000 to 30,000 year overlap.  The Neanderthals were believed to had co existed with modern humans in Europe for 20 or 30 thousand years. 

    Then there was a recalibration of the Carbon 14 data that showed the Neanderthal sites disappeared about the same time that sites of modern men appeared.  Which leads to the obvious conclusion that Neanderthals lost the competition with modern man and were wiped out.  Unpleasant idea, but likely.

Carbon 14 data is tricky.  Energetic particles from the Sun and cosmic rays strike ordinary Carbon 12, and turn it into radioactive Carbon 14.  This has a half life of 14 thousand years, a good long time.  Living organisms take in both sorts of carbon.  When the organism dies it stops taking in carbon.  By measuring the radioactivity from the carbon 14 in the organic material we can tell how many years has passed since the organism died.  It’s a delicate measurement; the radioactivity of the Carbon 14 is not very strong, compared to say Uranium.   It gets even weaker as time goes by, 14 thousand years, Carbon 14 half life, reduces the radiation by half. 

  I am not hep to just how the Carbon 14 dating was adjusted, but the result moved the oldest Neanderthal sites back 20 to 30 thousand years, putting then up again modern men moving into Europe.