Humans have long wondered whether life exists beyond our home planet. In recent years, a host of new technologies are turning speculation into science. We now have the ability to discern the atmostphere of an extra-solar planet so distant we can't even see it, to detect the presence of dozens of new planets circling stars similar to our own sun, and have discovered life in environments on Earth so extreme it's not unreasonable to imagine that microbes -- or more -- may flourish elsewhere in the Universe.