I was about ten years old when I first saw the PBS series Cosmos, hosted by the late astronomer Carl Sagan. I was a pretty bright kid, if I do say so myself, and I think I probably knew more about science and history at that age than a lot of grown-ups do now. Still, I was only a kid, which meant that a lot of the series’ content went over my head until I saw it again years later. Even so, I remember being utterly captivated by the big ideas behind Cosmos: that history, both of our puny little species and of the entire universe, is like an epic journey; that life, even intelligent life, may be ubiquitous in the universe but is nevertheless incredibly fragile and therefore precious; that knowledge and the quest to understand is at the core of our species; and that human beings are simultaneously — and paradoxically — insignificant in our scale to creation, but infinite in our spirits, destined for great things if we can only avoid destroying ourselves. I was equally fascinated by the show’s host, Dr. Sagan, who seemed to my ten-year-old self like such a gentle, kind-hearted man, but also, in some way I couldn’t quite put my finger on, a very sad man. I imagined that his sometimes grim demeanor must’ve come from his knowing everything there was to know, and that he suffered because of that awful, burdensome knowledge. (Yes, I really was a brooding Romantic even at the age of ten.)

Carl Sagan had a son, Nick Sagan, who grew up to become a science-fiction novelist. On his blog the other day, I found the following video clip from Cosmos, in which his father sums up so much of what that series was about. Curiously — or perhaps frighteningly — his words from almost 30 years ago still seem relevant today: