Galileo Galilei (1564-1642), an Italian thinker and key figure in the scientific revolution who improved the telescope, made astronomical observations, and put forward the basic principle of relativity in physics
Italian astronomer and mathematician who was the first to use a telescope to study the stars; demonstrated that different weights descend at the same rate; perfected the refracting telescope that enabled him to make many discoveries (1564-1642), Galileo Galilei
an Italian astronomer (=a scientist who studies the stars) , mathematician, and physicist whose many discoveries had a great influence on modern science. He discovered that the planets move around the Sun, and that if you drop objects of different weights in a vacuum, they fall at the same speed (1564-1642). born Feb. 15, 1564, Pisa died Jan. 8, 1642, Arcetri, near Florence Italian mathematician, astronomer, and physicist. Son of a musician, he studied medicine before turning his attention to mathematics. His invention of the hydrostatic balance ( 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. There he disproved the Aristotelian contention that bodies of different weights fall at different speeds; he also proposed the law of uniform acceleration for falling bodies and showed that the path of a thrown object is a parabola. 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 moons (see Galilean satellite). His findings led to his appointment as philosopher and mathematician to the grand duke of Tuscany. During a visit to Rome (1611), he spoke persuasively for the Copernican system, which put him at odds with Aristotelian professors and led to Copernicanism's being declared false and erroneous (1616) by the church. Obtaining permission to write about the Copernican system so long as he discussed it noncommittally, he wrote his Dialogue Concerning the Two Chief World Systems (1632). Though considered a masterpiece, it enraged the Jesuits, and Galileo was tried before the Inquisition, found guilty of heresy, and forced to recant. He spent the rest of his life under house arrest, continuing to write and conduct research even after going blind in 1637. NASA mission to study Jupiter and its Galilean satellites with an orbiting spacecraft and an atmospheric probe, launched in 1989. Though the failure of its high-gain antenna resulted in its data being transmitted back to Earth very slowly, the mission returned a wealth of valuable information. En route to Jupiter, the craft took the first detailed images of two asteroids. On its arrival in 1995, its atmospheric probe descended by parachute into Jupiter's upper cloud layers, detecting large thunderstorms. In a series of flybys of the Galilean moons, the orbiter observed volcanoes on Io hotter than any on Earth and found evidence of a liquid ocean below Europa's icy surface, a magnetic field around Ganymede, and a possible subsurface ocean on Callisto
Italian astronomer and mathematician who was the first to use a telescope to study the stars; demonstrated that different weights descend at the same rate; perfected the refracting telescope that enabled him to make many discoveries (1564-1642)