In part 1 of this story I told about the discovery of Sedna, the first – and still only – body found far beyond the edge of the Kuiper belt. Part 2 described some of our early theories on how Sedna had gotten there and what it was telling us about the early history of the solar system. Here I’ll begin talking about the most recent searches for more things like Sedna and how we’re doing so far.
Seven years ago, I knew with certainty that the discovery of Sedna in a strange orbit that never brought it close to any planet was telling us something profound about our solar system. I also knew that Sedna would never divulge her secrets alone. To learn more, we’d have to find more things like Sedna.