Shadow Propagation Speed
The farther the distance from the object blocking the light to the surface of projection, the larger the silhouette (they are considered proportional). Also, if the object is moving, the shadow cast by the object will project an image with dimensions (length) expanding proportionally faster than the object's own rate of movement. The increase of size and movement is also true if the distance between the object of interference and the light source are closer. This, however, does not mean the shadow may move faster than light, even when projected at vast distances, such as light years. The loss of light, which projects the shadow, will move towards the surface of projection at light speed.
The misconception is that the edge of a shadow "moves" along a wall, when in actuality the increase of a shadow's length is part of a new projection, which will propagate at the speed of light from the object of interference.
Since there is no actual communication between points in a shadow (except for reflection or interference of light, at the speed of light), a shadow that projects over a surface of large distances (light years) cannot give information between those distances with the shadow's edge.
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Famous quotes containing the words shadow and/or speed:
“Erasmus was the light of his century; others were its strength: he lighted the way; others knew how to walk on it while he himself remained in the shadow as the source of light always does. But he who points the way into a new era is no less worthy of veneration than he who is the first to enter it; those who work invisibly have also accomplished a feat.”
—Stefan Zweig (18811942)
“The greatest felony in the news business today is to be behind, or to miss a big story. So speed and quantity substitute for thoroughness and quality, for accuracy and context. The pressure to compete, the fear somebody else will make the splash first, creates a frenzied environment in which a blizzard of information is presented and serious questions may not be raised.”
—Carl Bernstein (b. 1944)