Here some clues:
clue1 (http://www.google.com/hostednews/ap/article/ALeqM5ibGHSvFxr9kgRVuSSMuSsk5CfQAwD9AL9GKO2), clue2 (http://www.heavyliftpfi.com/content/NewsItem.aspx?id=704) , clue3 (http://www.nytimes.com/2009/09/11/science/earth/11passage.html?hpw)