So, I read the Project Hail Mary book last year, and after watching the movie, I thought I'd listen to the audiobook this time. While doing so, I came across what I think may be a continuity error in the book. I'll explain in detail:
When Rocky rebuilds the xenonite tunnel with the clear xenonite wall, he places 2 balls on Grace's side, one representing the Hail Mary, the other representing the Blip-A. The Hail Mary ball has 2 rings of 8 beads each connected by a thread, which represents 2 molecules of oxygen (O2). The Blip-A ball has 29 rings of 7 beads, each with 3 individual beads connected to them, representing ammonia (NH3). The comparison shows that the Blip-A has 29 times the atmosphere of the Hail Mary.
In fact, when Grace compares Erid's atmosphere to Earth's, he says the same thing; Erid has 29 times Earth's atmosphere.
However, the sample of Grace's air that Rocky got from the tunnel was at the same pressure as the Hail Mary. But, as mentioned earlier, the Hail Mary was at 0.4* Earth atmospheres to make airlock decompression and recompression faster. By this comparison, Rocky's atmospheric pressure is not 1 x 29, it is actually 0.4 x 29, meaning it is actually 11.6 Earth atmospheres.
Another thing that bugs me: isn't there a ton of nitrogen in the Hail Mary to maintain the air pressure? How could it even be 100% oxygen? Wouldn't that cause oxygen toxicity to the crew?
So, I come to a few possible conclusions:
- The Blip-A is also set at 0.4 of Erid's atmosphere, so the ratio turns out to be equivalent anyway
- Andy Weir forgot this technicality, so Erid and the Blip-A are actually at 11.6 Earth atmospheres
- I'm dumb, and should read/listen to the book properly
I am completely open to being assaulted by corrections in my theory.
*Edit: The Hail Mary was actually at 0.2 Earth atmospheres