Question

The inner and outer planets, Mercury and Venus, Mars, Jupiter and Saturn, were identified by ancient Babylonian astronomers between 2000 to 1001 BC. It was not until the 1600's that Galieleo and Cassini, using telescopes, discovered what?

A) The planet Pluto.
B) Stars in other solar systems.
C) The moons of Jupiter and Saturn.
D) The fact that the moon is a satellite of Earth.

Answer 1

The moons of Jupiter and Saturn. Option C

Galileo Galilei used a telescope to make important astronomical observations in the 1600s. His discoveries included the rings of Saturn and the four largest moons of Jupiter, which are now referred to as the Galilean moons: Io, Europa, Ganymede, and Callisto.

These discoveries upheld Copernicus' heliocentric theory and transformed our knowledge of the solar system and other celestial bodies. It was not until much later that the other options—Pluto, stars in other solar systems, and the moon's status as an Earthly satellite—were discovered.