“Unafraid of the Dark” is a delightful, fascinating tale of the mystery of the universe we don’t yet know, and the perfect finale to ‘Cosmos: A Spacetime Odyssey.’ While still teaching new facts (ie., dark matter), it reiterates all of its past points. Don’t be afraid to make mistakes in the pursuit of knowledge, it says. Pursue the truth.

Just as importantly, in between explanations of dark matter and supernovas, it brings in one of Carl Sagan’s triumphs, the Voyager space probe. The episode explains the imagery on the disc we placed there should another intelligent species happen upon it, and then it reminds of us Sagan’s most famous speech.

When Voyager cleared Neptune, the camera was turned around to take one last photo of Earth, which looked like an unremarkable pale blue dot in a starry sky. It’s a reminder of how small we are, and how we need to protect the Earth’s resources, and its message is just as meaningful and immediate as it is today.

Even more beautifully, “Unafraid of the Dark” concludes this thirteen episode odyssey of trial and error of our greatest scientists on the same beach that the 1980s serial first began when Carl Sagan told the world he would take them on a journey through the cosmos on a spaceship of the imagination.

The series has been a wonder of knowledge, and expertly structured in both science as in poetry, and I can only hope that we will not have to wait another twenty years to get a new version.