The sun be crazy. Like, it's more or less a self-sustaining explosion that's so far away the energy of it takes almost ten minutes to cross the void to us, but is still so powerful it can burn and blind you if you're exposed to it for too long. And the effects are only that minor because our magnetosphere blocks most of the solar wind. That wind is coming at us at almost a million miles per hour
Yet society forces you to live under the huge burning ball of cancer generating plasma that defies the natural natural order of the universe.
-signed a night owl
a shadow is just a silhouette cast on a surface, so it can move much faster than light. An object moving near the speed of light in front of a small light source that casts a shadow on a very large, very distant object could appear to move billions of times faster than light (though you would need an extremely bright light source for the shadow to be noticeable to the naked eye)
there's really no upper limit, just how far you're willing to stretch the definition of "shadow" and "movement"
I've been pondering about responding to you. Since I can't see this as some sort of irony - here goes.
I'm sorry, but you're wrong. The shadow in your example would be bound by the speed of light, because the photons from the source of light are also bound by it.
A shadow is just a lack of photons on a surface surrounded by other photons.
The opposite of this realization is the plot of Nightfall by Isaac Asimov, now it makes me interested in a story about some kind of people realising that there is sunlight out there. I'm sure someone has made a story about this.