I can, however, rebut one point you said about there being no experiment to show different masses attracting each other on Earth. That's incorrect. You can look it up at Wikipedia: The Cavendish Experiment. Cavendish used heavy metal balls inside a glass cabinet (so air currents wouldn't affect the experiment) to measure the very, very weak attraction between them. He not only verified Newton's Law of Universal Gravitation, but was also able to calculate the Universal Gravitational Constant. Most college physics labs have this apparatus available for students to replicate the experiment Cavendish did.