How did Newton's theories explain why planets orbit the sun and why moons orbit planets?

Answer 1

Newton's theories of gravity and the laws of motion, with the differential calculus he also invented (Leibnitz did the same in Germany), explained why the planets and other objects obey Kepler's laws of planetary motion, which were deduced from observations.

It happens because of the Sun's gravity, an inverse-square force (which means that the force reduces with the square of the distance). Newton showed that a central force of this type produces an orbit exactly as Kepler had described many years before.

Different planets at different distances, with a range of different initial conditions, take up a family of orbits that all follow the same theory.

Answer 2

Newton's law of universal gravitation explains that objects with mass attract each other. The gravitational force between the Sun and planets causes the planets to orbit around the Sun, while the gravitational force between planets and their moons causes moons to orbit around planets. This gravitational attraction creates a balance between the object's inertia and the gravitational pull, resulting in stable orbits.