1564-1642, Italian astronomer, mathematician, and physicist was born in Pisa, Italy. He started Pisa University as a medical student in 1581 and became a professor of mathematics at Padua(1592-1610), where he improved the refracting telescope (1610) and was the first person to use astronomy. At the age of 19, he found out the principle of isochronism-that each oscillation of a pendulum takes the same time despite the changes in amplitude. He found experimentally that bodies do not fall with velocities proportional to their weights, a conclusion received with hostility because it contradicted the accepted teaching of Aristotle.
Galileo discovered the path of a projectile is a parabola, and he is credited with anticipating
Newton’s laws of motion. Newton’s three laws of motion are: (1) a body at rest tends to remain at rest, or a body in motion tends to remain in motion at a constant speed in a straight line unless acted on by an outside force; (2) the acceleration an of a mass m by a force F is directly proportional to the force and inversely proportional to the mass, or a = (F/m; (3) for every action there is an equal and opposite reaction.
The third law implies that the total of a system of bodies not acted on by an external force remains constant.
1609, he constructed the first astronomical telescope, which he used to discover the four largest satellites of Jupiter and the stellar composition of the Milky Way. In a deep study of the theory of refraction, and he prepared a tube, at first of lead, in the ends of which he fitted two lenses, both plane on one side, but on the other side one spherically convex and the other concave.
He said, he saw
objects satisfactorily large and near, for they appeared one-third of the distance off and nine times larger than when they are seen by the naked eye alone. He shortly constructed another telescope with more nicety which magnified objects more than sixty times. By adding a third lens, Galileo made it possible to see objects, not upside down, but in the correct position. By the time he had completed his fifth instrument, crowds began to stand for hours before his house.
Under house arrest in Florence, he continued his research, although by 1637 he had become blind.
A work that upheld the Copernican System rather than the Ptolemaic System and marked a turning point in scientific and philosophical thought. The first modern European heliocentric theory of planetary motion; placed the sun motionless at the center of the solar system with all the planets, including the earth, revolving around it.
Galileo died on January 8, 1642, in Arcetri (near Florence) (now in Italy).