After many, many attempts on worldbuilding, I decided to go back to an old project of mine.
I need to design a planet that, at the same time, is habitable but hostile to human life.
I would like it to have as its principal ecological feature a very, very dense fog that covers a large part of the surface of the planet, regardless of the season of the year. What would be the requirements to make such fog possible? What would be the climatic and ecological effects of a fog like that on a ecosystem similar to Earth's?
At the same time, it should be a darker planet, somehow. Thematically, I would like to explore the possibilities and consequences of darkness as a distinctive ecological feature on societies.
Maybe, although my planet shouldn't be tidally locked, it could have a twilight / dawn more extensive in time than Earth's. Could it be possible? How?
Is it possible that an Earth-like planet may have a night longer than the day? Could it be habitable for human-like species?