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Old 13-03-2015, 18:06   #9
Wittmann
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Re: What is Gravity ?

Quote:
Originally Posted by downquark1 View Post
Classically speaking the energy is always there. It's called gravitation potential energy.

As you lift a ball onto a table you are giving it the potential energy to fall back down. When it falls it will exhibit no more energy than what it took to lift it.

There was the view that all the potential energy in the universe would eventually cause it to end in a big crunch. But I don't think this is the favored model these days.
The ball is no example, the energy is supplied by you, an energy source.

Gravitational potential energy is energy an object possesses because of its position in a gravitational field. Huh ! Catch 22 ! We are back to gravity and where does it come from. What is it ? The base question of this thread.

Inert masses are incapable of exerting or generating energy. Back to the drawing board.
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