* BeamMeUpScotty: Sagan says "billions" with a strong "B" many times on this show, but he never utters the phrase "Billions and billions." That came from an affectionate parody of Sagan done by Johnny Carson on Series/TheTonightShow. WordOfGod has it that he found it annoying at first, but got over it. And the whole reason he said "billions" with a strong "B" was to emphasize that it wasn't millions, but three whole orders of magnitude greater. He lampshaded and did say the phrase years later in the prologue of his last book, mostly just to be able to say he actually said it. "So just for the record, Billions and Billions." He made it an AscendedMeme when he ''named'' the book ''Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium''. (Despite the parody, Sagan was a regular guest on the Tonight Show, and may have uttered the phrase during one of his appearances, too.)
** Tyson drops "Billions and billions" in the episode "Hiding in the light" pointing out that zero is useful when you write billions.
* BonusEpisode: The original VHS release of the series included an additional episode in which Sagan is interviewed by Ted Turner for an hour about the series and its concepts. This bonus episode is not included in the later DVD release.
* {{Defictionalization}}: The Mars rovers that Sagan spoke of in Episode 5, ''"Blues for a Red Planet"'', were defictionalized 23 years later with the highly successful [[http://en.wikipedia.org/wiki/Mars_Exploration_Rover Spirit and Opportunity]] rovers, and later the [[http://en.wikipedia.org/wiki/Curiosity_rover Curiosity]] rover. Also, the spacecraft ''Cassini'' did eventually reach Saturn and explored the system until September 2017, and its ''Huygens'' lander did successfully reach and photograph the surface of Titan, as Sagan had hoped.
* PlayingAgainstType: Most people would not normally associate Creator/{{Seth MacFarlane}}, he of ''WesternAnimation/FamilyGuy'' fame, with a science documentary. And even he [[SelfDeprecation says he's the least important person involved]]. And yet without him, the series likely would not have happened. And Ann Druyan has noted that Seth and Carl would have gotten along quite well.
* ScheduleSlip: Season Two of the 2014 reboot was delayed as Fox and National Geographic investigated sexual misconduct charges against Neil.
* ScienceMarchesOn: Interestingly, although many of the details are no longer accurate, remarkably few of the theories and principles Sagan discusses have been completely supplanted by more current research. The DVD commentary discusses this, and Ann Druyan, in her introduction to the first episode, states that, 20 years after the fact, at least, the series needed little revision. That said, when the series was rebroadcast by PBS in the early 1990s each episode ended with newly recorded comments by Sagan discussing any points either proven wrong or new discoveries related to the episode since it first aired.
* WhatCouldHaveBeen: At the time of his death, Sagan and his wife Ann Druyan were planning a new miniseries, ''Cosmos For Kids''. [[note]]The early-80s Japanese educational series ''[[Anime/MiimuIroiroYumeNoTabi Meme]]'' has very strong ''Cosmos'' influences.[[/note]]
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