The scene: Last night, bedtime. Phoebe: Mommy, are there monsters? Me: No, no monsters. Pho: There are no blue monsters to scare me? Me: No, there are no monsters here at all. Mallory: Phoebe, monsters aren't real. They're like vampires and unicorns and other things that aren't real. Pho: Oh! Mal: Mommy, what other things aren't real? Me: Um, dragons. Mal: Yeah. What else? Me: Dinosaurs. Mal: Dinosaurs are real! Me: Well, you're right. They used to be real, but there are no live dinosaurs now. Mal: I know what happened to them. Me: You do? Mal: Yeah! A big planet came and crushed them and they all ran away because they were scared and they died. Me: Hm. Mal: Is that right? Me: No one knows for sure, but yes, many people believe that an asteroid, which is a big big big big rock from outer space, crashed into the earth and changed the weather so much that the dinosaur's food couldn't grow, and so the dinosaurs died. Mal: Yeah, because if you don't have any...