What is more frightening? Believing to be alone in the universe, or think that there is someone else out there? Humanity always wondered about it, looking at the starry sky. But since some decades we have moved imagination to action. This book tells the story of the explorations carried out so far with often surprising results, which encourage us to continue to search for life in the cosmos. Did you know for example that each year many pieces of Mars fall on the Earth? And that in a comet it has been found one of our amino acids? Behind the corner there are important discoveries that will shed light on the other big question: how did life on Earth born? Giovanni Fabrizio Bignami, academic and member of the Lincei Academy of France, is among the most prominent scientists in astrophysics and space research. He identified Geminga, new neutron star, and has directed international projects and research institutes in Italy and abroad. He is very active in the diffusion of knowledge with books, articles, lectures and television programs.