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Q & A: gravitational potential energy.

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Most recent answer: 10/22/2007
Q:
The core of the earth is ’energized’ by the compression of mass above it. Since energy can be neither created nor destroyed, where prior did this energy exist?
- Stuart Doblin (age 44)
Prescott, AZ US
A:
When the Earth formed, pieces of previously separate matter clumped together, under the influence of gravity. As things get closer, they lose gravitational potential energy. That energy initially tends to go into the kinetic energy of large-scale motions, but thanks to friction it largely ends up as thermal energy in all the parts. I guess you'd say that the energy initially was associated with the separation of the different objects.
Since the Earth isn't really compressing any more, that's no longer a source of new thermal energy.

Mike W.

Lee H

(published on 10/22/2007)

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