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Q & A: relativistic points of view

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Most recent answer: 08/31/2008
Q:
The General Theory of Relativity says that when your for example in a space ship accellerating at 9.8m/sec your experiencing gravity, not a "like-gravity" force. If you let a ball go, the floor of the spaceship will rush up to meet it instead of it falling to the groud as we would think of normal gravity (I read this in the For dummies einstein book by the way). It says that gravity is exactly like that spaceship so when you jump in the air, the earth and the entire universe rushes up to meet you. Anyway now my question how can this be if two people on opposite sides of the earth jumped at the same time?
- Paul (age 14)
Canada
A:
Each of them can make a consistent description of the universe, obeying all the laws of physics, in which they themselves are at rest. These two different descriptions assign different values to the velocities and accelerations of various objects, such as the Earth.  

Think of looking at some box from different angles. Depending on your perspective, you'll give different values for its height, depth, and width. However, they're equally valid ways of describing the same box.

Mike W.

(published on 08/31/2008)

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