Gravity

Gravity is caused by rotation of large objects.  Mass alone does cause gravity, but an object of large mass and surface area will cause gravity based on the speed of its rotation generating force.  This gravity will affect other bodies in space, causing moons and asteroids to rotate and orbit, which create their own less powerful gravity due to the smaller size of these objects.  Multiple small objects could form a loose surface area with some gravity generated from their speed and rotation.  

The Earth's gravity is not caused by a "spinning molten core," but by the rotation of the entire mass of earth causing gravitational force based on the size of its surface area.

Absense of rotation equals zero gravity.  If the Earth stopped rotating, we would all start floating towards space.

>>1 FAIL.

A scientific law attempts to explain what happens in a given phenomena so that experiments can be conducted.

Newton stated objects are attracted to each other, and
objects of greater mass attract each other more than objects > of less mass.
A law is always true once it is correct.

You are dealing with gravity theory. A scientific theory attempts to explain how a phenomena occurs; theories, once proven to be true, are then scientific fact.