Mercury
The smallest planet and closest to the Sun, with dramatic day-night temperature swings.
Solar System Guide
The Solar System is our local cosmic neighborhood: one star, eight planets, many moons, dwarf planets, asteroids, comets, and icy bodies beyond Neptune. This site gives you a friendly path through the key ideas, with practical facts you can scan quickly.
Meet the 8 Planets
Venus
A rocky world with a thick atmosphere and runaway greenhouse heating.
Earth
Our ocean-rich home planet, the only known world with life.
Mars
A cold desert world with ancient river valleys and active exploration.
Jupiter
The largest planet, famous for its storms and many moons.
Saturn
Known for bright rings made mostly of water-ice particles.
Uranus
An ice giant tipped on its side, with unusual seasons.
Neptune
A distant, windy ice giant with powerful storms.
How the Solar System Works
Gravity is the main organizer of the Solar System. The Sun contains most of the mass, so planets orbit it in predictable paths. Inner planets are rocky and compact, while outer planets are larger and richer in gas and ice. Small-body regions like the asteroid belt and the Kuiper Belt preserve clues about early planet formation.
Planet motion is not random. Rotations create days, orbital periods create years, and tilted axes create seasons. Moons, rings, and magnetic fields add complexity that helps scientists test ideas about how planetary systems form and evolve.
Continue with topic pages: How Planets Form, Inner vs Outer Planets, and Solar System Moons.