It's a dark room, but I am able to see clearly the hand and the chair. If there are so much light that I see those objects, shouldn't I be able to see the ball as well?
thanks for the comments!
There is no room, only the ceiling and windows hanging in space, thats why its black.
Yes, the ball is floating.
The ball material is with 0 roughness, so that you dont see it. Thats the idea.