Human beings have long looked to the stars and hoped that alien life might look back at us. Yet the truth is that the first extraterrestrial life we discover is far more likely to be microbial — a prospect less romantic perhaps than the idea of bipedal aliens shaking hands with humans after landing on Earth.
Such microbial life has been theorized to have existed in the early days of Mars, before its water dried up, though we still don't know for certain. Now, astrobiologists are turning their gaze towards another nearby neighbor, Europa — an icy gray moon of Jupiter — as a suddenly much more alluring candidate for simple life.
