What happens when you cross medical science with geophysics?In one study published last year, the result was one-part interdisciplinary and one-part science fiction.

Scientists have studied the presence of a magnetic mineral, magnetite, in organisms, but work on the human brain has been far and few between. Tiny chains of magnetite crystals in the cells of magnetotactic bacteria, for example, help the bacteria swim in the right direction. Could pigeons, turtles, or even, humans, have built-in compasses too?

Stu Gilder, a geophysicist from Ludwig-Maximilian's University in Munich, wanted to find out. He and his coauthors, many of them medical professionals, published the first systematic look at magnetite in human brains. The results reveal that humans have concentrated areas of magnetite in the more “ancient” parts of the brain.

This episode was produced by Jenessa Duncombe and mixed by Kayla Surrey.