In Subspace Radio #92, Rob and I return from 65 million years in Earth’s past on a conspicuous chunk of iridium-rich rock to discuss “Valles Marineris” (SNW) before examining other closed-loop time puzzles that are best not to over-think. We consider the Bell Riots of “Past Tense” (DS9), the subspace fractures of “Time and Again” (VOY), and the Ed Begley Juniors of “Future’s End” (VOY).