Photos from space never cease to amaze, so it seems strange to have a favorite, especially one that’s so mundane — just a smiling, hardworking guy in a cramped interior, almost like an RV. But I’ve learned so much from Harrison Schmitt’s snapshot.The moon dust — Cernan looks more like a coal miner than a pilot. There are amazing stories about moon dust, but for now just a moment of peace for the last living human to set foot on the moon. It’s worth thinking about what it means that there aren’t any more.