[Vertigo]

Let's see if I can explain what I'm after here.

Imagine a moderately large habitat style spaceship, a rotating cylinder, say something like a 1000m in diameter and several km in length. Assuming no access to any kind of external sensors and no windows, is there any way you could tell if you were in orbit around a planet or just coasting through interstellar space?

I'm pretty sure I read something a while back that described a way of doing this.

Also how would such a thing orbit? Would it orbit end on, so that the cylinders axis points at the centre of the planet, or lengthwise so the axis is pointing along a tangent to the orbit?

I was wondering if you could do something like this:

The orbit radius is dependent upon the speed; faster speed, bigger radius. If the ship is orbiting end on then the orbit radius would be based on the speed of the cylinder's centre of gravity. So if you floated a balloon at one end of the cylinder would it then naturally drift towards the centre to get it's (the balloon's that is) orbit radius right for it's speed.

If it was orbiting lengthwise, would there be a measurable difference in the centrifugal pseudo-gravity when the spin of the cylinder places you closest to the planet as oppopsed to when it places you farthest away from the planet?

Hope that makes sense!