Saturday Citations: Moon origins, rat whimsy, microgravity orientation. Plus: Starfish are bodiless heads, it turns out

Good morrow and a cheerful week's end to you. This week, we reported on notable developments in the lack of starfish body development. Physicists used a new method to revisit the planetary collision that likely formed the moon and might have found chunks of doomed planet Theia deep in the Earth's mantle. And in experiments, rats, as seen in the subway, are demonstrating the power of imagination, as seen on LeVar Burton's "Reading Rainbow." Worlds collide!