Far beyond Neptune, a handful of extreme trans-Neptunian objects like Sedna and 2012 VP113 make their closest approaches to the Sun in roughly the same direction, with similarly tilted orbits. This episode explains why that clustering should have smeared out over billions of years of precession, and why Konstantin Batygin and Michael Brown calculated a vanishingly small chance of it happening at random, pointing instead to a hidden shepherding mass.

We examine the current profile of Planet Nine, including 2025 estimates near 4.4 Earth masses at roughly 290 AU, and the formation puzzle: a super-Earth could not have formed that far out, so it must have been flung there during early giant-planet instability, slowed by residual gas or a passing star, or captured from elsewhere. We also give the skeptics full weight, including Samantha Lawler's  ...