Time and distance

  • Thread starter kwerk
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In Brian Greene's article The Time We Thought We Knew, he writes:

"Were you to board a spaceship, head out from earth at 99.999999 percent of light speed, travel for six months and then head back home at the same speed, your motion would slow your clock, relative to those that remain stationary on earth, so that you'd be one year older upon your return -- while everyone on earth would have aged about 7,000 years."

What if you instead flew the spaceship in close circles around the earth (close enough to be observed). Would people on earth observe you flying for 7000 years? Inside the spaceship you should experience 1 year, so would you have traveled 1 light year or 7000 light years?

Or did you travel both distances? 7000 viewed from earth but only 1 viewed from inside the spaceship.
 

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  • #2
bcrowell
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What if you instead flew the spaceship in close circles around the earth (close enough to be observed). Would people on earth observe you flying for 7000 years?
Yes.

Inside the spaceship you should experience 1 year, so would you have traveled 1 light year or 7000 light years? Or did you travel both distances? 7000 viewed from earth but only 1 viewed from inside the spaceship.
This is basically right, except that in your own frame you traveled zero distance, while the Earth moved.
 

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