Solar System Overview

Our solar system is a giant family of objects held together by the gravity of the Sun. At the center is the Sun — a huge, glowing star. Eight planets travel around the Sun in nearly circular paths called orbits, along with moons, asteroids, comets, and dwarf planets like Pluto. Even though the planets look small in the sky, some of them are bigger than thousands of Earths put together.

The Eight Planets in Order

1. Mercury — the closest planet to the Sun and the smallest of the eight.
2. Venus — the hottest planet, wrapped in thick clouds that trap heat.
3. Earth — the only planet with liquid water on its surface and life.
4. Mars — the red planet, with rusty soil and the largest volcano in the solar system.
5. Jupiter — the largest planet, famous for the Great Red Spot, a giant storm.
6. Saturn — the planet with the most beautiful rings of ice and rock.
7. Uranus — an icy blue planet that spins on its side.
8. Neptune — the farthest planet, deep blue and very windy.

Inner and Outer Planets

Scientists split the planets into two groups. The inner planets — Mercury, Venus, Earth, and Mars — are small and rocky. The outer planets — Jupiter, Saturn, Uranus, and Neptune — are huge balls of gas and ice with no solid surface to stand on. Between the inner and outer planets is a wide ring of leftover rock called the asteroid belt.

• Inner planets: small, rocky, close to the Sun, few or no moons.
• Outer planets: huge, gassy or icy, far from the Sun, many moons and rings.
• Asteroid belt: zone of rocky pieces between Mars and Jupiter.

Why It Matters

Knowing the order and features of the planets helps you read space pictures, follow real space missions, and ask better questions about how the solar system formed. Each planet teaches us something different about our own home, Earth.