On a rubber mat
In the classical physics Newton's laws of gravitation explained gravity as a fundamental attractive force between any objects having mass. According to a legend Isaac Newton realized that there must be a force when an apple dropped from a tree. Around 1687 he presented that the force behaves same way between the Earth and moon or Earth and any object. Later the mathematical presentation of the gravitational force was determined as it's strength was proportional to the masses and inversely to the their distance square. Additionally, to make equation to work in the standard units a multiplier called gravitational constant was needed. By1862 James Clerk Maxwell described that electric and magnetic fields are generated by charges and currents. Analogously, Gauss's law for gravity presented gravity as a field caused by mass according to Newton's law in the classical physics. In the early 20th century the modern physics changed our understanding of the reality. The theory o