full name Galileo Galilei. 1564–1642, Italian mathematician, astronomer, and physicist. He discovered the isochronism of the pendulum and demonstrated that falling bodies of different weights descend at the same rate. He perfected the refracting telescope, which led to his discovery of Jupiter's satellites, sunspots, and craters on the Earth's moon. He was forced by the Inquisition to recant his support of the Copernican system

a US spacecraft, launched 1989, that entered orbit around Jupiter in late 1995 to study the planet and its major satellites; burned up in the planet's atmosphere in 2003