[Stark_GOP]

"Hasn't Stark_GOP been told this before? We need to keep track of the names of the creationists who are told the difference between "theory" and "law", especially those who use the term "Law of Gravity" and are corrected on the matter so we can find out who is genuinely ignorant and who is willfully ignorant."
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http://en.wikipedia.org/wiki/Gravity

Newton's law of universal gravitation states the following:

Every object in the Universe attracts every other object with a force directed along the line of centers of mass for the two objects. This force is proportional to the product of their masses and inversely proportional to the square of the separation between the centers of mass of the two objects.

[Dimensio]

So why does that force exist? What causes it?

Newton's Law doesn't explain that. It simply provides a means for making statements about what force will result from two masses in any given observation. That's why it is not and has never been a theory.