It seems that we expect an alien civilization, if it exists, to follow a similar discovery path as we did. As such we listen for radio signals as a way of communication, because that's what we are doing.<p>How likely is it for another civilization to follow the same path? Some of our breakthrough scientific advances happened by accident. What are the odds that we missed some big new technologies because we haven't happened upon the accident yet, even though it was right here all the time?