A gravitationally bound system of the Sun and all the things that orbit it, there is one
star, 8 planets, (used to be 9 (with Pluto) but considered to be a dwarf planet in 2006.) and
5 dwarf planets recognized by the IAU.
In prehistoric times, the first 7 planets (including
Luna, our moon.) and the Sun were discovered. In the Copernican system, the Moon was considered to be no longer a planet.
Luna was originally thought to be the only body in the system whose revolution was not centered on the Sun. The next 2 planets,
Uranus (yuhr-uh-nus) and Neptune, weren't discovered until 1781, when
Uranus was discovered, and 1846, when Neptune was discovered. Many of
Jupiter's (Galilean moons) and Saturn's moons were discovered during the 1600s. In 1787,
Uranus' first two moons, Titania and Oberon were discovered. 2 years later, Saturn has two more moons discovered. In 1801, Ceres was finally discovered by Giuseppe Piazzi, After Neptune was discovered in 1846, in the same year, Neptune's moon (Triton) was found. 2 years later, a moon of Saturn has been found. In 1851,
Uranus has two more moons. In 1877, the two moons of Mars were finally founded by Asaph Hall. Years later, a moon of
Jupiter and a moon of Saturn was discovered. Going to the 1900s, 4 more moons of Jupiter were found. Then in 1930, Pluto was found! But later on in 2006, after 76 years, Pluto was now considered a dwarf planet. Most of the dwarf planets were found in the 21st century.
