Celestial mechanics

The Celestial Mechanics is a branch of astronomy and mechanics aimed at studying the motions of bodies under gravitational effects exerted upon him other celestial bodies. The principles of physics known as classical mechanics apply Law of Universal Gravitation by Isaac Newton ). It studies the motion of two bodies, known as the Kepler problem, the motion of the planets around the Sun , its satellites, and the calculation of the orbits of comets and asteroids. It is the science that studies the motion and mutual gravitational pulls of celestial bodies in space.


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  • 1 Origin
  • 2 Discovery
  • 3 Contributions of scientists
    • 1 Nicholas Copernicus
    • 2 Galileo
    • 3 Newton
    • 4 Einstein
  • 4 Sources


Its birth can be made to coincide with the publication by Isaac Newton (1624.1727) of his Principle, that is, with the formulation of the theory of universal gravitation. Continuing this science were, in the 18th century , the Swiss physicist and mathematician Euler , who made precise calculations on the movement of the Moon , the major planets, and comets, and the Frenchman Alexis Claude Clairaut who calculated the disturbing effect of the planets on Halley’s Comet . In the following century, the most important discovery due to celestial mechanics is, without a doubt, the location of the planet Neptune from the measured disturbances onUranus . The calculation was independently performed by scientists JC Adams and U. Leverner.

The modern development of celestial mechanics allows the calculation of the trajectories of the probes for the exploration of the Solar System . Thanks to the help of computers, it has been possible to take advantage of the passage of the probes next to the planets to obtain fantastic accelerations and path deviations, which have led the probes themselves to successive appointments with other celestial bodies.


Marie Curie

Whoever observes the sky with a minimum of diligence very soon finds that there are stars that after a few days describe irregular trajectories, which also travel at variable speed, even giving rise to reversals of movement, albeit temporarily. In the 6th century the Ionian philosopher Anaximenes of Miletus called them Planets (the wanderers), a term that has remained in use ever since to differentiate them from the Stars . The first clear ideas about the movement of the planets were given by Eudoxius (408 – 355 BC). Its system consisted of concentric crystalline spheres, which with their regular movements reproduced the planetary movements, for themovements of the Sun required three; for the Moon three; four for each of the known planets, and a part of the starry sky; twenty-seven in all.

Aristotle modified the Eudoxium system transforming it into a compact mechanical model, which required fifty-five spheres to account for planetary movements; in both systems land occupies the center. Aristarchus of Samos was the first to formulate the Heliocentric TheoryThis astronomer worked from 310 to 230 BC and Archimedes was the most brilliant of the mathematicians of antiquity; who lived from 287 to 212, tells us that “Aristarchus wrote a treatise on certain hypotheses that fixed stars and the sun remained motionless and that the earth rotated around the sun according to a circumference, the sun being in the center of the orbit Hipparchus Greek astronomer worked on the island of Rhodes, he was the compiler of the catalog that has come down to the present day through Ptolemy in his Almagest.

Ptolemy in the second century of our era, made the review of Hipparchus and collected ancient observations of eclipses. But chaotically it preserved the geocentric theory, where the planets together with the sun are supposed to rotate around the earth in a period of one year, describing circular or deferential orbits. In addition, the five planets describe orbits with uniform motion on the vas. As a collapse of astronomy, the church supported the Ptolemy system, for about 1200 years until in 1543 a Polish cleric named Copernicus proposed a system where the planets rotate in circular orbits around the sun, Copernicus pointed to Aristarchus as the inspiration for the work. While the Catholic Church was swift, Copernicus received the printed copy on his deathbed inIn 1550 , in 1600 an astronomer named Giordano Bruno was condemned to the stake for supporting Copernicus’ ideas and in 1616 his work was placed among the heretics.

Contributions of scientists

Nicolaus Copernicus

Nicholas Copernicus formulated a theory that bodies did not revolve around Earth , but around the Sun. He also noted that gravity was the mechanism responsible for the movement of planets.


Galileo Galilei invented the first telescope and made the first planetary observations. Galileo discovered that all objects fall at the same speed and regardless of their mass.


Isaac Newton’s Universal Law of Gravitation states that each pair of particles in the universe attract each other. The attractive force of two bodies is directly proportional to each mass and inversely proportional to the square of the distance that separates them.


Albert Einsteinsolved Why gravity caused the planets to move. In his general theory of relativity he solved the equation proposed by Newton. Gravity was produced by a curvature in space-time. Its equivalence principle explains gravity as the free fall from one object to another. An orbit is really a straight line. An object falling toward another is traveling in a straight line through space-time. However, the curvature of time bends its path in a closed orbit and at the same time, space causes it to curve over itself. The distance between two points is precisely that space of curvature. Einstein affirmed that one could not speak of time and space separately, but inserted within the same concept. An object with greater mass will have greater gravity.


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