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:
“There is no shadow of protection to be had by sheltering behind the slender stockades of visionary speculation, or by hiding behind the wagon-wheels of pacific theories.”
—Madame Chiang Kai-Shek (b. 1898)
“There was such speed in her little body,
And such lightness in her footfall,
It is no wonder her brown study
Astonishes us all.”
—John Crowe Ransom (1888–1974)