If there were a sphere or a cube where time is stopped, how would someone passing by perceive that? I have something in mind that stops everything, including air and light, not only solid matter.
My first thought was, if nothing comes out it must be pitch black. But that would lead to this region building up enormous amount of energy over time, absorbing all light. When the time starts moving again I think this would result in some kind of huge catastrophe eliminating everything inside the area (and probably outside too).
Not only when time stops there should be no change at all. So no energy build up. But also it would be inconvenient for the plot ;)
But if it can't be black, how should it look? Bonus points for how it would feel to touch it.