Page 377 - Encyclopedia Of World History Vol IV

1678 berkshire encyclopedia of world history

What moves men of genius, or rather what inspires their work, is not
new ideas, but their obsession with the idea that what has already been
said is still not enough. • Eugene Delacroix (1798–1863)

time that is needed. Galileo formulated this law in 1604 For this reason in 1600 he became an assistant to the
and made it public in 1632 in his book Dialogo sopra I Danish astronomer Tycho Brahe (1546–1601), who
due Massimi Sistemi del Mondo (Dialogues of the Two established the regular observation of stars and planets on
Chief Systems of the World). He described the law in the sky. When Brahe died in 1601 Kepler possessed a
detail in 1638 in his book Discorsi e Dimostrazioni huge amount of astronomical observations.From them he
Matematiche intorno a due nuove scienze attenenti alla finally formulated his famous three astronomical laws: (1)
Mecanica e I movimenti locali (Speeches and Mathemat- The orbits of the planets are ellipses,with one of their foci
ical Demonstrations around Two New Sciences Pertain- the sun. (2) A line joining a planet and its star sweeps out
ing to Mechanics and Local Movements). equal areas during equal intervals of time. (3) The square
According to tradition Galileo proved the accuracy of of the sidereal period of an orbiting planet is directly pro-
the law with experiments that he performed in the Tower portional to the cube of the orbit’s semimajor axis.
of Pisa, but historical evidence has not fully supported The first two laws were published in 1609 in Kepler’s
that tradition. On the contrary, he performed experiments book Astronomia Nova (New Astronomy), which shows
using an inclined plane that had been constructed to min- Kepler’s transition from animistic to mechanistic thought.
imize friction.
Furthermore, Galileo clarified the concept of inertia Newton
and expressed it in a form that was not far from the form Isaac Newton’s contributions to the Scientific Revolution
of the law of inertia that Newton proposed later. were many and included his mechanical universe and his
Galileo also was among the first scientists to use a tel- universal laws. His Philosophiae Naturalis Principia
escope to observe the heavens. He presented one of his Mathematica was possibly the most influential scientific
first telescopes to the doge (chief magistrate) of Venice, ask- book ever published. It contained his laws of motion,
ing that Galileo’s professorship be made permanent at the which formed the foundation of classical mechanics, as
University of Padua and receiving a doubling of his salary. well as his law of universal gravitation. Many scholars
Galileo’s observations of the surface of the moon and also credit Newton with inventing calculus.
the satellites of Jupiter, published in 1610 in Sidereus The mechanistic concept was the mainstream of scien-
Nuncius (Sidereal Messenger), supported the Copernican tific thought during the seventeenth century.The concept’s
system. However, many scientists disputed these obser- most important representative was the French mathe-
vations and questioned the reliability of observations matician and philosopher Rene Descartes (1596–1650).
made with a telescope. He argued that matter is everywhere in the universe and
To win over such skeptics Galileo used a clever strata- proposed his vortex theory to explain the movement of
gem: He sent his book and a telescope to members of the celestial bodies. He believed that fine matter in the ether
nobility to gain their political support. forms vortexes around the sun and other stars.
However, the Catholic Church finally forced Galileo to Although science would prove Descartes’s theory inad-
renounce Copernicus’s system, and tradition says that equate, its contribution was important because eventually
after his renunciation Galileo whispered “yet it moves.” no one would cite supernatural powers to explain phys-
ical phenomena.
Kepler Such advances created the necessary setting for the
The astronomer Johannes Kepler published his book next decisive step—the synthesis of a new view of the
Mysterium Cosmographicum (The Secret of the Universe) world. The person most prominent in creating this new
in 1596.When he realized that his theory about the move- view was Newton, who believed that the orbits of the
ments of the planets Mercury and Saturn was wrong he planets are determined by a central force that is reduced
began to try to improve the accuracy of his observations. in inverse proportion with the square of the distance.