If the question is life - and that's one of the most profound questions we can ask, he says - the answer is almost certainly not Mars or an asteroid, but rather the icymoons orbiting distant planets like Saturn and Jupiter.
"One of the most fascinating aspects of Enceladus is that it's so very small as icymoons go, but so very geophysically active, " said Dr Bob Brown, from the University of Arizona, US, and team leader for Cassini's visual and infrared mapping spectrometer.