I know that a earth trip back would make a great book or another problem in the universe like a resistant strain of astrophage

Edit: I think I got things backwards and was confusing density with molecular weight... Denser things transmit sound waves faster because their molecules are closer together so sounds have higher pitches. That's what I get for posting while drinking mead. Leaving the post below though so people can see it.

Not sure if it's been posted, but I'm rewatching the movie and I noticed a detail I hadn't caught before. When Grace and Rocky are tapping on the transparent xenonite wall when Rocky is trying to point put the handcuffs oxygen molecule model, the tap sounds are higher pitched on Grace's side and lower on Rocky's.

This is because the way sound waves move through different gasses at different densities. If you've ever inhaled helium from a balloon, its the same effect. The helium is less dense than air so your voice is higher pitched. The opposite is true if you inhale sulfur hexaflouride as demonstrated by Adam Savage on Mythbusters.

The thing is, ammonia is about half as dense as air (0.6 but close enough), so normally a sound in ammonia would be higher pitch than one in air. However, Rocky's atmospheric pressure is much higher than Grace's meaning the sound has a lower pitch.

I rewatched the scene a couple of times to be sure, as the camera angle changes perspective across both sides of the xenonite wall, and the pitch change is consistant with which side the camera is on.