I'm surprised no one has pointed out that the opening animation in the show displays a solar system of ring worlds around a central star and different rings at different orbital inclinations that appear to be changing over time, resulting in variations of shadow seasons for the outer rings. This is consistent with the zoomed in maps that are in the opening scenes as well where the world's curvature can clearly be seen to be consistent with a ring. I noticed it in the first episode when I watched and was a little surprised they never addressed it directly, but I watched the whole series and didn't notice any scenes that would be inconsistent with this world structure.

I'm surprised no one has pointed out that the opening animation in the show displays a solar system of ring worlds around a central star and different rings at different orbital inclinations that appear to be changing over time, resulting in variations of shadow seasons for the outer rings. This is consistent with the zoomed in maps that are in the opening scenes as well where the world's curvature can clearly be seen to be consistent with a ring. I noticed it in the first episode when I watched and was a little surprised they never addressed it directly, but I watched the whole series and didn't notice any scenes that would be inconsistent with this world structure.

This discussion with the title sequence creator even mentions the concept of the world being inside a dyson sphere: Link