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Know the Cosmos and our place within it.
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“Exploration is in our nature.” - Carl Sagan

Articles

Stories, updates, insights, and original analysis from The Planetary Society.

Saturn within its rings

Why do some planets have rings and others don't?

The giant planets of our Solar System all have rings, as do some dwarf planets and even asteroids. So why don’t Mercury, Venus, Earth, or Mars?

Haumea with a ring (artist's rendering)

Meet the Solar System's five official dwarf planets

The International Astronomical Union currently recognizes five dwarf planets: Ceres, Pluto, Haumea, Makemake, and Eris.

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