How does viewing a movie on the sphere work? From my understanding it’s a sphere that displays things on the outside. Wouldn’t this mean you would only be able to see only a small part of the screen at any given time?
It's got two screens! One inside and one outside.
The interior screen is 16k by 16k pixels (the 18k camera resolution affords some cropping for image stabilization etc).
The exterior screen doesn't have much in the way of specs other than area, but I'd expect it is comparably lower pixel density.