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Planety Goodness and the Darkest Hours
So I've pretty much decided that this is going to be a moon of a gas giant at this point. Which of course gives me a whole other set of things to decide!
First, of course, is the obliquity of the planet's rotation. The reason this is important is that it determines the relative inclination of the moon's revolution about the planet, and thus directly affects a) the seasons, and b) the eclipses. (The obliquity is the angle of the axis, relative to the orbital plane.)
There are a lot of eclipses.
The moon is tidally locked to the gas giant, meaning each day/night cycle is a single revolution about the planet. Probably somewhere in the vicinity of one of our weeks. Now, what this means is that every single day, the planet will eclipse the sun. The only case in which it wouldn't is if the planet has a pretty large obliquity, in which case it would only eclipse a few times a year or something.
Now, this doesn't have to be a complete eclipse every day. It could just be a partial eclipse. It depends on your location on the moon's surface and on the planet's obliquity/inclination of the moon's orbital plane. (Picture, if you will, the vast curve of the planet overhead, part of it eternally dipping below the horizon. Every day, the sun rises in the east, soaring across the sky. At the apex of its daily arc, it slowly dips behind the great planet, sending the world into a noontime darkness. And this is a perfectly normal and regular occurrence!)
Another interesting part of being a large moon orbiting a gas giant is that you can see your moon's shadow on the surface of the planet in the sky.
An interesting biological/evolutionary aspect of this is that there is no real concept of nocturnal or diurnal, because the length of the night or day is entirely too long to sleep through most of either of them. Animals will need to be functional in both times of day.
On the flip side of that, the planet itself will reflect quite a lot of light down during the night, so it never gets very dark. Except at noon! The darkest time of the day/night cycle.
First, of course, is the obliquity of the planet's rotation. The reason this is important is that it determines the relative inclination of the moon's revolution about the planet, and thus directly affects a) the seasons, and b) the eclipses. (The obliquity is the angle of the axis, relative to the orbital plane.)
There are a lot of eclipses.
The moon is tidally locked to the gas giant, meaning each day/night cycle is a single revolution about the planet. Probably somewhere in the vicinity of one of our weeks. Now, what this means is that every single day, the planet will eclipse the sun. The only case in which it wouldn't is if the planet has a pretty large obliquity, in which case it would only eclipse a few times a year or something.
Now, this doesn't have to be a complete eclipse every day. It could just be a partial eclipse. It depends on your location on the moon's surface and on the planet's obliquity/inclination of the moon's orbital plane. (Picture, if you will, the vast curve of the planet overhead, part of it eternally dipping below the horizon. Every day, the sun rises in the east, soaring across the sky. At the apex of its daily arc, it slowly dips behind the great planet, sending the world into a noontime darkness. And this is a perfectly normal and regular occurrence!)
Another interesting part of being a large moon orbiting a gas giant is that you can see your moon's shadow on the surface of the planet in the sky.
An interesting biological/evolutionary aspect of this is that there is no real concept of nocturnal or diurnal, because the length of the night or day is entirely too long to sleep through most of either of them. Animals will need to be functional in both times of day.
On the flip side of that, the planet itself will reflect quite a lot of light down during the night, so it never gets very dark. Except at noon! The darkest time of the day/night cycle.