Gravitational Physics, also known as classical mechanics or Newtonian physics, is the branch of physics that describes the motion and interactions of celestial bodies under the influence of gravity. It is named after Sir Isaac Newton, who developed the laws of motion and universal gravitation in the 17th century. The key concept of Gravitational Physics is the force of gravity, which is the attractive force between two objects with mass. This force is directly proportional to the masses of the two objects and inversely proportional to the distance between them.