Reading Journal 5 - The Theory of Gravitation

In this section of Six Easy Pieces, Feynman discusses the theory of gravitation. Despite gravities simplicity and the obvious presence of this seemingly strong force, it is a rather weak force when compared to nuclear forces (force binding the nucleus of atoms together), and electrical forces (positive and negative repulsion and attraction). By far the strongest of the three being nuclear forces and electrical forces are far still stronger than gravity. Gravity is only “inversely proportional to the mass of each and varies inversely as the square of the distance between them” (Feynman 89), (F=G(mm^1/r^2). In other words the bigger the two objects and the smaller the distance between them, the stronger the force will be. Feynman also discusses that the reason the Earth and other planets are circular is that gravity is pulling them as close together as they can be. The planets are not circles, however, they are ellipsis. They are ellipsis because the planet’s rotations causes a centrifugal effects which tend to oppose gravity around the equator spreading the middle of the planets farther out than the rest of it. Other than the brief background on gravitation and the explanation of the planets’ ellipsis shape, Feynman discusses the effects of gravity on moving objects. He states that because something is moving while be pulled it results in a curved motion. As if the object is strafing around the pull. This motion describes the revolutions of the planets around the sun, and the moons around the planets. Gravity most helps us predict the motion and position of stars. This is the reason gravity is used so often in astronomy. It is likely that the reason gravity was discovered so early was human natures fractionation with space and the stars. Without gravity we would know very little because without gravity we would not notice very much scientific.