http://education.guardian.co.uk/higher/research/story/0,9865,1369270,00.html I was especially struck by this I remember listening to one of the astronauts who went to the moon...I think Armstrong...who years later commented on this. After his lunar trip and while still in biological isolation, one day he looked down and saw that ants were crossing the isolation barrier through a small crack in the concrete. He was laughing about this but also emphasizing the need for extreme caution wrt potential threats like this. Mistakes happen. If moonbugs could have killed everyone on earth, they might have. A sobering thought, I thought.