Annie McEwen went to a mountain in Pennsylvania to help catch some migratory owls. Then Scott Weidensaul peeled back the owl’s feathery face disc, so that she could look at the back of its eyeball. No owls were harmed in the process, but this brief glimpse into the inner workings of a bird sent her off on a journey to a place where fleshy animal business bumps into the mathematics of subatomic…