A popular theory holds that ocean water was brought to Earth by the ancient impacts of comets and asteroids. However, new data from the European Space Agency?s Rosetta spacecraft indicate that terrestrial water did not come from comets like 67P/Churyumov-Gerasimenko.
FULL STORY: http://science.nasa.gov/science-news/science-at-nasa/2014/14dec_cometwater/
