This scene is commonly seen: A huge starship levitates over the surface of a planet or a moon, staying effortlessly in one place, or moving slowly around at the fixed height. But how?
- Doesn't make noise or much of the noticeable influence below, except by making a huge shadow. It can make some effect measurable by sensitive instruments, but humans usually won't feel a thing.
- Doesn't rely on the atmosphere, i.e. it can levitate equally well over the planets and moons with no atmosphere.
- Can levitate above any solid surface, i.e. doesn't require special infrastructure or alloys below.
- Doesn't expend (much) energy in order to stay in place.
- It behaves as if some fixed height is a point of equilibrium (like with floating objects).
- Can levitate above liquid surface.
With the minimum possible amount of hand-waving, how can a massive starship achieve this?
EDIT: To make things more clear, I'm thinking about starships like those from Independence Day and District 9, Star Destroyer over Jedha city in Rogue One and other floating starships and vechiles from SW and so on.
And it doesn't need to be possible with the currently known physics, but I'd like an answer that uses only Occam's-razor-like minimal required amount of new physics (e.g. if one approach needs a fifth force and another needs space wizards, I'll prefer the former). Imagine that a physicist sees such a starship and tries to explain it.
EDIT2: Typical height above the ground should be comparable to the ship's (horizontal) size.