That's a great question! It depends on the situation. Here's a breakdown:

* A luminous object itself does not cast a shadow. A shadow is formed when an opaque object blocks light from a light source. Since the luminous object is the light source, it can't be blocked by itself.

* However, a luminous object can cast a shadow if it's shining on another opaque object. Think of the sun, which is luminous. It casts shadows on the Earth because the Earth blocks the sunlight.

Let me know if you have any other questions!