what is petrova line?

The Petrova Line in Project Hail Mary is a key astronomical phenomenon tied to how humanity discovers the threat posed by Astrophage:

What is the Petrova Line

1. It’s an arc or streak of infrared light observed extending from the Sun toward Venus, first detected by astronomer Irena Petrova. This feature becomes known as the “Petrova Line.”
2. The line isn’t just a visual oddity—it’s tied to strange “dots” or dimming phenomena along its length, which seem to block or reduce the Sun’s output to Earth. Observations of this line spark alarm because they indicate something is interfering with sunlight.

Why it matters

• The Petrova Line is the trail that leads scientists to realize the existence of Astrophage, a microorganism that drains solar energy and uses the line to travel between the Sun and Venus. This sets off the chain of events that forces humanity to try to stop the impending environmental collapse.
• Understanding and sampling along the Petrova Line is one of the first critical scientific efforts in the story. The samples collected lead to the discovery of Astrophage’s biology and behavior.

If you want, I can show how the Petrova Line compares with similar plot devices in sci-fi, or how it functions in the film vs. the book.