A goat standing on a cow’s back. That’s the hook of the story. But as much promise as that image seems to provide as it comes through the speakers, it’s just an entry point into a story that starts with letters written by American soldiers during WWII that were found in the dirt on the side of the road when a middle-school teacher pulled over to try to see the goat standing on the cow’s back. Those letters, all to one woman from different soldiers, are clues to a whole other fascinating story, presented in the creative, magnetic way that is typical of Radiolab, the syndicated radio show that takes listeners on explorations of science and other curiosities. You might already know that the show plays locally in rotation with other short-run programs on North State Public Radio Presents (Sundays, 3-4 p.m., on KCHO, 91.7FM), but you don’t have to wait for one of the only five episodes produced per year to show up on the airwaves. Every show from all nine-plus seasons is available for free (supported, in part, by the donations of listeners like you, of course) in podcast form at radiolab.org—including 2007’s “Goat on a Cow.” You can also subscribe to the podcast for free, and listen to the newest episodes (including the new Radiolab Shorts that air between episodes) at your leisure.