You walk out of “The Most Unknown” knowing a little more than you did, and with the sense there’s so much more you don’t. It’s a mystifying feeling, and a good reason to see this documentary that extols the wonders of science and of all that’s yet to discover.

The film begins deep underground as Jennifer Macalady, an American geomicrobiologist, explores simple life-forms found in the Frasassi Caves in Italy. As part of the documentary’s plan she travels to visit a scientist she has never met, who studies a discipline she is unfamiliar with — Davide D’Angelo, an Italian physicist researching dark matter — to discuss some of his work and how their fields may overlap.