It’s an image of a particle collision. Abhijat Mital, one of the book’s characters, is a theoretical physicist. The book’s about a town whose residents are in conflict over plans to build the Superconducting Super Collider (a tool for studying particle physics) under their homes, schools, and farmland.
Did you pass high school physics?
Barely. And only thanks to a kind physics teacher who was either unable to do basic math while computing my grade or–more likely–was just ridiculously kind and indulgent with his students.