The Mayor Finding in the Physics History

Irmary Ortiz Carlo 

          If you ask to different physicians the same question: Which was the mayor finding in the physics history? Everybody will give you a different answer. Everyone has a different point of view of what was the best contribution of the physics to the science.  But a lot of scientists and physicians think that the best finding in the physics history was the Universal Law of Gravitation, of Isaac Newton. In 1687, Sir Isaac Newton in his work Philosophiae Naturalis Principia Mathematica formulated the three principles of the movement, and the fourth, The Universal Law of Gravitation, that transformed the physical world completely. All the phenomena could be seen in a mechanical way. This law states that all the objects are attracted with others with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance that separates its centers. When putting under a single mathematical law the more important physical phenomena of the observable universe, Newton demonstrated that the terrestrial physics and the celestial physics are a same thing. The gravitation concept obtained of a single blow:

Reveal the physical meaning of the three laws of Kepler about the planetary movement.

Solve the intricate problem of the origin of the tides.

Give to account of the peculiar and inexplicable observation of Galileo Galilei of which the movement of an object in free fall is independent of its weight.

        Newton compares the centripetal acceleration of the Moon, with the gravity acceleration. In the physics previous to Newton, an apple falls vertically towards the Earth in a rectilinear trajectory, whereas the Moon describes an almost circular orbit, which is a closed trajectory.  How these two categories of movements can be related?  If the apple that fell vertically is pushed by the force of the air, its trajectory no longer will be rectilinear but the arc of one curve. For example a projectile shot from a tube describes a parabolic trajectory as it was observed in the century XVII in which Newton lived. The conceptual jump that carried out Newton was the one to imagine that the projectiles could be shot from the stop of a mountain describing elliptical trajectories (being the parabola an approach of the ellipse). Therefore, the apple and the Moon are falling. The difference is that the Moon has a movement of permanent fall, whereas the apple hits the Earth surface. A same cause produces, therefore, the movements of the celestial and terrestrial bodies.

    Maybe, it can be hard to choose between all the fantastic findings that the physics history has. But the reality is that the Newton’s Universal Law of Gravitation changes the physics history forever.  

 

Bibliography:

http://www.sc.ehu.es/sbweb/fisica/celeste/kepler4/kepler4.html