That there are not significate amounts of dark matter wihtin our solar system.
The dark matteris a component of the universe whose presence is discerned from its gravitational attraction rather than its luminosity.
The force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface is known as gravitational attraction.
The luminous normal matter, such as protons, neutrons, electrons, and atoms in the universe, there are about 4 grams of nonluminous normal matter, mainly intergalactic hydrogen and helium.