http://boards.straightdope.com/sdmb/sho ... ostcount=8
Quoting their quoting of the opening paragraph:
That's some good scientific paper to back up this comic.Calculating the Velocity of Darkness and its Possible Relevance to Lawn Maintenance
The velocity of light is approximately 186,000 miles/sec. This velocity, often represented as a constant (c), is of central importance to our present understanding of physical law. In contrast, the velocity of darkness (as manifested by the movement of the edges of a shadow) is not constant; nor is it generally derived for simple systems. The derivation presented here demonstrates that shadows are capable of moving at speeds much greater than the speed of light. Further, it is demonstrated that shadows can exhibit the unusual attribute of arriving at their destination before leaving their origin. The practical implications of these results are completely unknown, but are discussed at length anyway.