Our solar system consists of the sun, planets,moons, dwarf planets, asteroids, comets, meteors, and others. Of all the planets in our solar system, the six nearest the Sun can be seen with the naked eye. So these planets Mercury, Venus, Earth, Mars, Jupiter, and Saturn- have been observed since ancient times. The first planet to be discovered using a telescope was Uranus, in 1781. Neptune, the eighth planet was discover only in 1846. Pluto was discovered in 1930, but in is now not classified as a planet,and so Neptune is considered to be the last planet to be discovered in our solar system.