Great question — answering as the UphillTech team:
Your question could be interpreted as either: Our Earth doesn't have a view like this. What is different about these planets that makes this view correct? The answer to this is simple. Earth is a planet, with a smaller orbiting moon. Both examples of inhabited "planets" you show here (Panora and Annwn) are smaller moons orbiting larger planets. You would expect, especially in the case of Pandora, orbiting a much larger gas-giant, to see this represented in the sky. Or why do the writers and directors choose a situation like this for their stories? This is a little harder to have a distinct verifyable answer since it may vary from story to story. However it does provide a distinctly alien...
Full answer by iandotkelly: https://movies.stackexchange.com/a/116490 (CC BY-SA 4.0).
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