A distand light source illuminates the scene with the three wheels from above and behind as shown by the shadow of the static red wheel.
It is clearly visible that the rolling wheel always outruns its shadow. Also, the shape of the shadow appears not to match the shape of the wheel, this is most obvious in the case of the green wheel in Figure 12b.
These observations, too, can be explained by considering light travel times because these times differ on the different paths from the object to the eye, on the one hand directly and on the other hand indirectly via the shadow.
Contact: Would you like to be notified of new contributions or to send us a message?
Survey: How do you use this site and how would you like it to develop?