The Meta-Encyclopedia

Galilei

Collier's New Encyclopedia (1921)

GALILEO (gä-le-lā'ē), a commonly called Galileo (gal-i-lē'ō), in distinguished Italian physicist; born Pisa, Italy, Feb. 18, 1564. His father, Vincenzo Galilei, a nobleman of Florence, intended him for the medical profession; but his love of mathematical studies was so decided that he was allowed to pursue them. At the age of 24 he was approfessor at Pisa. pointed mathematical There he was constantly engaged in asserting the laws of nature against the scholastic philosophy, which raised up GALILEO such a host of enemies against him that in 1592 he was obliged to resign his professorship. He then went to Padua, where he lectured with unparalleled success, and students flocked to hear him from all parts of Europe. After remaining there 18 years, Cosmo III. invited him back to Pisa, and then to Florence, with the title of principal mathematician and philosopher to the grand-duke. Galileo had heard of the invention of the telescope by Janson, and making one for himself. He found that the moon, like the earth, has an uneven surface, and the he taught his scholars to measure height of its mountains by their shadow. His most remarkable discoveries were Jupiter's satellites, Saturn's ring, the Sun's spots, and the starry nature of the Milky Way. The result of his discoveries was his decided conviction of the truth of the Copernican system; though the blind conservatism of the monks charged him with heresy for it, and he was twice prosecuted by the Inquisition, first in 1615, and again in 1633. On both occasions he was compelled to abjure the system of Copernicus. In the following year, when he was 70 years old, and his health was declining, a very heavy blow fell on him by the death of his beloved daughter, Maria. Two years later he became blind. His latter years were spent near Florence, devoting himself to the perfecting of his telescope. His greatest work is the "Dialogue on the Copernican and Ptolemaic Systems." Among his others are "Dialogues on Motion," "Sidereus Nuncius," "Treatise on the Sphere, etc." He died in Arcetri, near Florence, Italy, Jan. 8, 1642. His remains were ultimately deposited in the Church of Santa Croce at Florence.

What Has Changed in the Last Century

The life Collier's sketched in 1921 is still the life we know, but two details have been corrected: the grand duke who called Galileo home to Tuscany in 1610 was Cosimo II, not Cosimo III, and what he saw around Saturn were puzzling "handles" he never resolved — the ring was identified by Christiaan Huygens in 1655. The 1615 episode is now generally described not as a prosecution but as a warning delivered in 1616, with the single trial coming in 1633. The largest shift is on the Church's side: the ban on Copernican works had gone in the eighteenth century, but only in 1992 did John Paul II accept the findings of a commission that the theologians who condemned Galileo had erred. Historians have also grown sceptical of the Leaning Tower experiment, which rests on a late account by Galileo's disciple Viviani.

Written for this edition, 2026.