I have been thinking about this on-and-off, recently. What is the difference between the Sagan Cosmos, and the Tyson Cosmos? There are lots of fairly uncharitable things to say about both of these men, but if we were forced to provide an actual explanation, I think three things could be said: Era / Audience. The original Cosmos was released in 1980. Not since the early eighties, have I felt the same sense of optimism and yearning for the promise of the future.