space bookies
"as long as the probability of taking a single, unsterilized particle, measuring no less than 10 nanometers in diameter, contains a single microbe is less than 0.000001 per cent"
Who's setting those odds, though? Since we can say very little about the possibility of Martian microbes from whatever landers / rovers there, how are these odds estimated if not by basically making them up out of a bunch of assumptions?
Reminds me of Feynman's assertion in the shuttle investigation that every layer of management at NASA had an order-of-magnitude lower estimate of failure possibility than the layer below. When the data is so sparse, probability calculations are hardly better than guesswork.