Worms can think, Charles Darwin said. The naturalist wrote in his last book, which was devoted entirely to the study of the beast, that “[w]e may therefore infer—improbable as is the inference—that worms are able by some means to judge.” So what do you suppose goes through a lowly oligochaete’s mind as it’s scarfed down by an even lowlier reality-show contestant? Oddly, author and worm enthusiast Amy Stewart doesn’t tackle this question in her latest book, The Earth Moved: On the Remarkable Achievements of Earthworms, but she does explore some scary realities of their underground world. “The more I know about what they’re capable of,” she writes, “the more I wonder whether it is such a good idea for them to outnumber me a million to one right here at home.” Stewart speaks at 10:30 a.m. at Green Spring Gardens Park, 4603 Green Spring Road, Alexandria. Free. For reservations call (703) 642-5173. (Mike Kanin)