A free idea.
Out at the edge of the sensible universe is Pluto. Not the orange cartoon dog. I'm talking about something much less normal. Pluto is a rock that's sometimes a planet and sometimes not depending on the vagaries of people. Pluto, of course, cares nothing for our opinion and carries on doing what it does (which isn't much) anyway.
Orbiting Pluto is Charon, one of Satan's names, but in this case it's a lump of rock commonly known as a 'moon'. Earth has one of these. Ours is a rock too and we haven't thought of a name for it so we just call it 'the moon'. It's really embarrassing when uninhabited planets have more imaginatively-named moons than we do, you know.
On those rare occasions when the clouds part over Dume Swamp, I've caught the occasional glimpse of The Moon. It doesn't look like a good place for a holiday.
Earth's moon moves about the sky. Pluto's does not. Pluto's moon is orbitally locked, which means it's in the same place in the sky all the time. If you were to spend a day on Pluto, the sun would move across the sky but the moon looks as though it's nailed in place.
Therein lies the idea. I'm not sure if it can be a horror idea but the SF folk might be able to pick it up. It's free. I'm not going to do anything with it. No copyright.
Imagine if Earth's moon was orbitally locked. If you were born, lived and died on one side of the planet, you'd never see a moon. If you were born, lived and died on the other side, the moon would be permanently fixed to the sky.
So one culture has a perfect view of the stars with no moonlight in the way. The other has the moon permanently fixed in place, day and night. If the moon orbit and the inclination to the sun matched, there might even be (for part of the world) a total solar eclipse every day.
Eventually those cultures will meet. Those of the Moon will place the Moon above the sun, because while the sun comes and goes, the Moon is eternal and (for some) demonstrates its power by defeating the sun every day.
Those on the No-Moon side won't know about the Moon and will more likely worship the Sun.
So the moon men will declare themselves more important because the moon beats the sun each day, while the sun men will declare the moon a hoax, and the moon men deluded.
Or any other twist you like.
Can you use such an idea? Go for it. I'll never use it. It's free, I won't be coming after you for royalties later.
I just don't like to see ideas disappear.
