Other contributors have said "What causes a formation of a shadow?" is the same question as "What is Shadow Formation?" If you believe that these are not asking the same thing and should be answered differently, click here
The property is that light travels in straight lines.(this is true only in normal gravitational conditions in very high gravitational fields this is wrong.) So when an object is placed in its path...
Because he absorbs or reflects light like any other solid object. Yes that and the fact that everyone and everything will have and always has had a shadow.
If I understand you correctly, you are saying that a bird flying in the sky does not have a shadow. If this is the case, it is not true. Birds do have shadows. I have noticed shadows of birds flying...
It depends on how the light hits the object. This may be applied to the division between the rings of Saturn, called the Cassini Division. It should carefully noted shadows are dependent on secondary...