Video narration
How many worlds really belong in our solar system-eight, nine, or even more? Think of it like a neighborhood map: the Sun is the main reference point, and the planets travel around it. Starting at the Sun and moving outward, the order is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. That makes Earth number three, with Mercury first and Venus second. Here's the part that clears up the confusion: "planet" is a category, not every round object in space. Pluto is round and travels around the Sun, but it belongs to a different category: a dwarf planet. The Moon is different too-it travels around Earth, so it is Earth's natural satellite, not a planet. So how many planets are in our solar system? Eight planets, and Pluto is a dwarf planet. Earth is the third from the Sun.