From the startling Copernican revelation that the Earth was not the centre of the Universe, humanity has wondered if life is unique to our world. But how likely is it that the Earth is the only reservoir of life in the vastness of space? Come along for the ride as early planetary researches learn that conditions on our neighbouring planets may be too hostile to support life and discover how recent findings hint there may be alien life "hiding out" in places we've overlooked.

• David McNab

• Samuel West