- Beam Me Up, Scotty!: 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 The Tonight Show. Word of God 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 Ascended Meme 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.
- Bonus Episode: 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 Spirit and Opportunity rovers, and later the 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.
- Playing Against Type: Most people would not normally associate Seth MacFarlane, he of Family Guy fame, with a science documentary. And even he 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.
- Schedule Slip: Season Two of the 2014 reboot was delayed as Fox and National Geographic investigated sexual misconduct charges against Neil.
- Unintentional Period Piece:
- In the third episode Sagan is shown picking up a copy of the New York Post which announces "THE BEATLES ARE BACK!". John Lennon was murdered two months after the episode first aired.
- The episode where Sagan explains how the Voyager data was received and collected now doubles as a fascinating portrait of the state of computer technology in The '70s. Data was collected on "magnetic disks, much like a phonograph record."note
- What Could Have Been: At the time of his death, Sagan and his wife Ann Druyan were planning a new miniseries, Cosmos For Kids. note
Trivia / Cosmos