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Q & A: gravity and energy

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Most recent answer: 10/22/2007
Q:
Geavity is a force. So to influence ’spacetime’ it must need to expend energy. Where does this energy come from and why does it never run out? MUWAHAHAHAHA! Answer that, if you dare!!
- Muhammed (age 17)
Sir George Monoux College, London
A:
Gravity isn't really a force but rather a distortion of spacetime, i.e. a difference from simple flat geometry. It doesn't need to influence spacetime because it is spacetime. We approximately treat it as a force when we pretend that spacetime has a simple geometry.

As for the part about energy, you know that it the classical Newtonian approximation, the field energy (potential energy) can be converted to kinetic energy when things fall, and vice versa when massive objects move apart. I'm not sure what the problem is. MUWAHAHAHAHA!

Mike W.

(published on 10/22/2007)

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