Galileo: Quick Facts

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Nov. 12, 2026

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Facts

Also Known As	Galileo Galilei
Born	February 15, 1564 • Pisa • Italy
Died	January 8, 1642 (aged 77) • Italy
Inventions	Galilean telescope • hydrostatic balance • thermometer • compass
Notable Works	“Dialogue Concerning the Two Chief World Systems—Ptolemaic and Copernican” • “The Sidereal Messenger”
Notable Family Members	father Vincenzo Galilei
Subjects Of Study	Jupiter • Milky Way Galaxy • Pleiades • Sun • Copernican system • Galilean satellite • Galilean transformations • gravity • motion • planet • solar system • sunspot • pendulum

Did You Know?

Galileo constructed his famous telescope without having seen an example of the Dutch instruments.
Galileo designed a new form of hydrostatic balance, an instrument for weighing objects using air and water.

Photos and Videos

Galileo's telescopes

Six sepia-toned sketches by Galileo show different phases of the Moon, each with shaded and illuminated areas, on aged paper with handwritten numbers and notes.

Engraving by Galileo Galilei showing the Copernican heliocentric system with the Sun at the center, planets in concentric orbits, and Jupiter with four orbiting moons.

Engraving from Galileo Galilei's 1613 work showing a circular diagram of the sun with labeled sunspots scattered across its surface.

$Engraving of Father Christoph Scheiner observing sunspots by projecting the sun's image through a refracting telescope onto a screen, with another man seated at a table.$

frontispiece to Galileo's Dialogue Concerning the Two Chief World Systems, Ptolemaic & Copernican

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