Discovery of the Petrova problem

Grace recalls a dinner conversation with his friend Marissa, a Department of Energy employee. Marissa reveals that the sun's output is decreasing exponentially due to a mysterious energy-siphoning phenomenon called the Petrova line, discovered by Russian astronomer Irina Petrova. The line, an arc of infrared light from the sun's north pole to Venus, is stealing the sun's energy, threatening Earth with an ice age and mass starvation. This memory establishes the existential crisis that drives the entire plot: the sun is dying, and humanity must find a solution.