Which pioneering scientist discovered the moons of Jupiter?

The discovery of the moons of Jupiter is credited to Galileo Galilei, who made this significant observation in 1610. Using one of the first telescopes, he was able to observe four large moons orbiting Jupiter: Io, Europa, Ganymede, and Callisto, now collectively known as the Galilean moons. This discovery was crucial because it provided strong evidence against the geocentric model of the universe, which held that all celestial bodies revolve around the Earth. Instead, it supported the heliocentric model proposed by Copernicus, which argued that planets, including Earth, revolve around the Sun. Galileo's findings not only changed our understanding of the solar system but also marked a pivotal moment in the history of astronomy, demonstrating the importance of empirical observation and the use of instruments to advance knowledge.

Other scientists mentioned in the choices made significant contributions in their own rights. Isaac Newton developed the laws of motion and universal gravitation, Johannes Kepler formulated his laws of planetary motion, and Carl Sagan was known for his work in astrobiology and science communication, but none were involved in the discovery of Jupiter's moons.