In this episode, we talk about Chapters 7, 8, and 9 of Foundation and Earth, "Leaving Comporellon," "Forbidden World," and "Facing the Pack." I've largely stopped bothering with the spoiler warnings, but I'm going to spoiler enough in this episode description to warrant one. If you want to discover things as you read and you haven't read these chapters yet, you know what to do. Tau Ceti is the nearest "sun-like star" to Earth that isn't in a multiple-star system and so it's been a frequent locale in Science Fiction over the years. It was a natural choice for Asimov to place Aurora, the first of the Spacer Worlds, in the Tau Ceti system. Since Asimov made that decision, we've discovered and cataloged thousands of exoplanets, that is, planets orbiting stars other than our sun. Several of them are in the Tau Ceti system and two, Tau Ceti d and e, are super-Earths that appear to be at the outer edges of Tau Ceti's habitable zone. That seems to fit what we learn about Aurora in this book; it was a terraformed world that, without humans to maintain it, was slipping back into uninhabitability. There is another, proposed, exoplanet orbiting Tau Ceti, called PxP-4. That one could be smack in the middle of the habitable zone. In any event, it's time to return to the Tau Ceti system and take a good look around. Also, there are dogs! So Let's go!