Learn the planets in order from the Sun, plus key facts, memory tricks, and why Pluto is no longer counted among them.

Learn why gravity, motion, and orbital balance keep planets circling stars instead of flying away or falling inward.

Learn why the asteroid belt exists, how Jupiter shaped it, and what it reveals about the solar system’s formation.

Explore how planets rotate, what drives spin and tilt, and why different worlds have dramatically different day lengths and axial behaviors.

Learn what the Kuiper Belt is, where it sits in the solar system, what it contains, and why astronomers study it closely.

Discover why Venus is the hottest planet in the solar system and how its atmosphere traps extreme heat.

Explore how moons form, why planets keep them, and what their diversity reveals about the Solar System.

Learn what a comet is, how it forms, why it glows, and what makes these icy solar system objects so scientifically important.

Mercury endures extreme heat, solar radiation, and gravitational stress through an airless surface, a metallic core, and a tightly bound orbit.