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Q & A: no rest for the weary

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Most recent answer: 10/22/2007
Q:
Is anything at rest? It seems the idea of anything being íat restí in relationship to anything else is flawed. From the macro to the micro, nothing is íat restí. Galaxies are moving away from other galaxies and sub atomic particles are spinning and in constant motion. What gives?
- Jack (age 35)
Hard Knocks U., Oregon
A:
We certainly donít think that anything is at rest (or not) in an absolute sense. The whole development of physics from Galileo through Einstein has worked best by discarding the idea that absolute motion has any meaning.

However, two different objects can often be at rest with respect to each other for at least a while. Consider the two ends of a stick. The distance between them hardly changes. If the stick isnít twirling around, the direction from one end of the stick to the other also isnít changing much, at least in frames which assume that the whole universe isnít twirling around.

Mike W.

(published on 10/22/2007)

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