The “Petrova line” in Project Hail Mary is not something being physically blocked by an object; it’s the visible trail of Astrophage traveling between the Sun and Venus, and the Hail Mary uses a Petrovascope to see it. In the scene people usually mean, what looks like a blockage is really the ship or perspective cutting across the line of sight, not the line itself being stopped.

What it is

  • The Petrova line is the infrared trail associated with Astrophage activity.
  • It appears as a line because Astrophage is moving along that path between bodies in the system.

What seems to “block” it

  • In viewer discussions, the “blocked” effect is often just the ship or another object crossing in front of the camera’s view.
  • In the movie or visual adaptation, the Petrovascope display can make the line look interrupted depending on angle, framing, or where the ship is positioned.

Simple reading

If you mean “why does the Petrova line look cut off in that moment,” the answer is: the view is being obscured, not the Astrophage line itself.

TL;DR

Nothing is truly blocking the Petrova line in-universe; it’s a visual line of Astrophage, and any “blockage” is usually just the ship or the camera angle obscuring the view.