And yet that was a snapshot of a dynamic process. Seeing an image of the horse didn’t actually reveal how it galloped, we had plenty of those and got it wrong.

And yet that was a snapshot of a dynamic process. Seeing an image of the horse didn’t actually reveal how it galloped, we had plenty of those and got it wrong. Seeing many images of the dynamics did, that’s a subtle but important difference. Movies are way more helpful than photographs. A crystal (or cryoem) structure is a snapshot of a horse standing still. We rarely care about that, though maybe we can guess that it uses its hind legs intensely because it’s very muscular. We do care about how it gallops, and don’t have a clue how with a single picture. Put another way, we have “pictures” of dinosaurs, but have limited understanding of how they socialized, interacted, moved. We have ideas and guesses, sure, most based on descendants and modern context. Hypotheses, but few answers. Now if we had a movie of a dinosaur...