Galileo Galilei was an Italian physicist, astronomer, mathematician and philosopher who was one of the founders of modern science and played a major role in the Scientific Revolution of the 17th Century.
By his investigation of natural laws he laid foundations for modern experimental science, and by the construction of astronomical telescopes he greatly enlarged humanity's vision and conception of the universe. Also he gave a mathematical formulation to many physical laws.
Galileo's main contributions in science include; discovering the constancy of a pendulum's swing, formulating the law of uniform acceleration of falling bodies; describing the true parabolic paths of cannonballs and other projectiles; coming up with the ideas behind Newton's laws of motion; and confirming the Copernican theory. Galileo also worked in applied science and technology: he invented a horse-powered pump to raise water building the first high-powered astronomical telescope, improving compass design.
Contributions to Physics. While professor (1589-92) at the University of Pisa, he initiated his experiments concerning the laws of bodies in motion, which brought results so contradictory to the accepted teachings of Aristotle that strong antagonism was aroused. Galileo proved that objects with different masses fall at the same velocity. Galileo put forward the theory of hydrostatic balance and the theory on the center of gravity of solid bodies.
Contributions to Astronomy. His achievements include improvements to the telescope and consequent astronomical observations, and support for Copernicanism. The first to use a telescope to study the skies, he discovered (1609 – 10) that the surface of the Moon is irregular, that the Milky Way is composed of stars, and that Jupiter has four largest satellites of Jupiter (Callisto, Europa, Ganymede, and Io). He observed and studied the oval shape of Saturn, the phases of Venus, and the spots on the sun.
Scientific methods mathematics.
Galileo made original contributions to the science of motion through an innovative combination of experiment and mathematics.
Galileo unquestionably holds that science based on observation is the true source of knowledge of the physical world, as opposed to traditional authority and philosophical speculation.
He also advocates a becoming modesty concerning what we know about nature, in opposition to the dogmatic certainties of much late medieval thought. The conception of the world associated with modern science is frequently referred to as the Galilean world view.
His invention of the hydrostatic balance (c. 1586) made him famous. In 1589 he published a treatise on the centre of gravity in solids, which won him the post of mathematics lecturer at the University of Pisa.
In 1591 his father died and he was entrusted with the care of his younger brother Michelagnolo. In 1592, he moved to the University of Padua, teaching geometry, mechanics, and astronomy until 1610. There, in 1609, having heard reports of a simple magnifying instrument put together by a lens-grinder in Holland, he constructed the first complete astronomical telescope.
At the age of 8, his family moved to Florence, but he was left in Pisa under guardianship of Jacopo Borghini for two years.
Although a genuinely pious Roman Catholic, Galileo fathered three children out of wedlock with Marina Gamba. They had two daughters, Virginia in 1600 and Livia in 1601, and one son, Vincenzo, in 1606.
His acceptance of the Copernican system was rejected by the Catholic Church, and under threat of torture from the Inquisition he publicly recanted his " heretical" views. He spent the rest of his life under house arrest, continuing to write and conduct research even after going blind in 1637.
Galileo was a true Renaissance man, excelling at many different endeavors, including lute playing and painting.
He died on 8 January 1642 in Arcetri.
Remains: Buried, Santa Croce Church, Florence, Italy.