Life elsewhere?

Yesterday I heard a lively and informative lecture by Professor Mike Edmunds about when and if we will find life elsewhere in the universe. I had often wondered in vain why it is so vital to discover evidence in just one more place bur he explained it clearly. If such evidence is found, say on Mars, it proves that our planet is not unique in this way and, since we know now there are many, many other planets, we may be sure that life must occur in other places. Scary?