# ## EINSTEIN   RELATIVITY

One of the peculiar aspects of Einstein's theory of special relativity is that the length of objects moving at relativistic speeds undergo a contraction along the dimension of motion. An observer at rest (relative to the moving object) would observe the moving object to be shorter in length. That is to say, that an object at rest might have be measured to be 200 feet long; yet the same object when moving at relativistic speeds relative to the observer/measurer would have a measured length which is less than 200 ft. This phenomenon is not due to actual errors in measurement or faulty observations; the object is actually contracted in length as seen from the stationary reference frame. The amount of contraction of the object is dependent upon the object's speed relative to the observer ## Spaceship Moving at the 10 % the Speed of Light Spaceship Moving at the 86.5 % the Speed of Light

## Spaceship Moving at the 99 % the Speed of Light ## Spaceship Moving at the 99.99 % the Speed

### Observed Height

At rest
200 ft
40 ft
10 % the speed of light
199 ft
40 ft
86.5 % the speed of light
100 ft
40 ft
99 % the speed of light
28 ft
40 ft
99.99 % the speed of light
3 ft
40
Note that the length contraction is only significant when the object is moving at relativistic speeds - i.e., speeds which are a significant fraction of the speed of light. Furthermore, note that the contraction only occurs in the dimension of the object's motion. That is, if the object is moving horizontally, then it is the horizontal dimension which is contracted; there would be no contraction of the height of the object