Discovery of the Petrova problem

The discovery of the Petrova problem begins with a single email. Dr. Irina Petrova, an astronomer at the Pulkovo Observatory in St. Petersburg, Russia, writes to the Astronomy Curiosities mailing list in search of help. She has spent two years working on a theory related to infrared emissions from nebulae, and during that work she made detailed observations in specific IR bands of light. What she found was not in any nebula but in Earth's own solar system: a very faint but detectable line emitting infrared light at the 25.984 micron wavelength, with no variance. The line is a lopsided arc that rises straight up from the Sun's North Pole for 37 million kilometers, then angles sharply down and away from the Sun toward Venus. At Venus, the arc's cross-section is as wide as the planet itself. To be certain of her findings, Petrova calls in a favor from the Atacama observatory in Chile, which she considers the best IR observatory in the world, and they confirm her results. She speculates that the arc could be space dust, particles moving along magnetic field lines, or some molecular compound absorbing and re-emitting energy, but she notes that Venus has no magnetic field to speak of, making the shape and behavior of the line particularly puzzling.

The Threat Escalates

The discovery takes on a far more urgent dimension when Ryland Grace, a former astronomer turned junior high school science teacher, receives a flash of memory while recovering from a coma aboard the Hail Mary. He remembers a conversation with his friend Marissa, who works for the U.S. Department of Energy. Over steak and beer at Murphy's on Gough Street in San Francisco, Marissa reveals that JAXA's Amaterasu solar probe has detected that the Sun's output is decreasing. The decrease is not part of the normal eleven-year solar cycle; it is a downward trend that is accelerating exponentially. JAXA scientists have determined that the Petrova line is getting brighter at the same rate the Sun is getting dimmer, meaning the line is somehow stealing energy from the Sun. Marissa shows Grace a graph with an exponential curve: the Sun's output will drop a full percent over the next nine years, and five percent within twenty years. Grace immediately understands the implications: an instant ice age, crop failures, mass starvation. The president of the United States is set to address the nation the next morning, coordinating with other world leaders to announce the crisis simultaneously.

The Scientific and Global Response

The discovery of the Petrova problem triggers an unprecedented global response. The world's space agencies and governments unite under the leadership of Eva Stratt, a Dutch administrator given near-absolute authority by a unanimous secret vote of every UN member nation. Stratt recruits Grace, despite his controversial academic past, because of his expertise in speculative extraterrestrial biology and his paper arguing that life does not require liquid water. The ArcLight probe, the most expensive unmanned spacecraft ever built, is sent to Venus to collect samples of the material making up the Petrova line. When ArcLight's microscope reveals that the black dots in the samples are moving and appear to be microbes, the world realizes it is facing an alien life-form that is consuming the Sun's energy. The microbe is later named Astrophage, and the exponential growth of its population is directly linked to the exponential dimming of the Sun. The discovery of the Petrova problem thus becomes the catalyst for the entire Hail Mary mission, as humanity races to find a solution before the Sun's energy loss triggers a global catastrophe.