I have this Earth-like planet that is running short on materials, like minerals and gasses, and they have a big spaceship that is able to gather materials from a gas giant that orbits the same star the planet does. What materials might the planet need that a gas giant could be realistically made of?
I am no expert, thus I'm asking, but I know that for an atmosphere to be breathable you need at least Nitrogen and Oxygen and that the gas giants in the Solar System are mainly made of Hydrogen (please correct me if i'm wrong). Now, it doesn't necessarily need to be a gas giant, but it must be at least a planet made of something the main planet is needing, like solid nitrogen that once melted gets pumped into the atmosphere, but is that even possible? What materials might a planet in a super distant future need for its own survival?