What is wrong with skepticism? What is wrong with saying " I don't know " ? I recommend reading Peter Ward's " Rare Earth " . Given the Over-abundant research and data listed in that book, i would say Khipu is rather spot on. Listing the fact that you " Know Scientists " is rather like living in LA and saying you " know some famous people". None of the ones listed in your references are specialists the Astronomical or Geological sciences. I would like to say that, yes, possibly a good chance exists when you think of the Milky Way or our Universe. but when you get into the distances involved and the actual probability of it, it becomes a bit more desolate than one would imagine.