Yeah, I was thinking radio communication would be the most likely scenario. I was thinking they'd be different species that developed separately up to a point. Of course once communication was possible they could have shared knowledge from then on. But then again, one race could consider itself supe...

I'm looking for a book, or books, that contain a story about two alien worlds in the same system where the aliens can see there's another world with intelligent life there but they haven't the technology to travel to each others worlds yet. I think there's a great potential to explore the implicatio...