What We Know


The Basics

  • Just the Pluto/Charon Facts
  • The Family of Planets
  • Pluto's Gravity
  • Orientation of Pluto and Charon
  • Pluto's Orbit Around the Sun

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Pluto's Orbit

  • Inclined to be Eccentric
  • Pluto's Orbital Dance with Neptune

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Discovery of Pluto

  • Percival Lowell: Search for Planet X
  • Clyde Tombaugh: The Discoverer of Pluto
  • Discovery Images
  • Pluto Gets a Name

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Discovery of Charon

  • Christy and Harrington: The Discoverers
  • The Discovery Image

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Discovering New Moons

  • Nix and Hydra
  • Kerberos
  • Styx

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What's In the Names?

  • How Did Pluto (the Planet) Get its Name?
  • Pluto in Classical Mythology?

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Pluto & System: Family Album

  • Keck Telescope
  • Subaru Telescope
  • Hubble Map
  • False Color Map
  • Pluto and Charon
  • New Moons
  • Color Map

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What Is a Binary Planet?

  • Binary planet
  • Other Binaries in the Solar System
  • Make a model of the Pluto/Charon system

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Phases & Seasons

  • Here's Looking at You!
  • Cycle of Phases
  • 'Tis the Seasons
  • Seasons on Pluto

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Making Maps

  • Even the Best Images are Fuzzy
  • Mutual Eclipses of Pluto and Charon
  • Turning Light Curves into Maps

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Surface Composition

  • It's Cold!
  • Observing Pluto
  • Icy Surfaces
  • Pluto's Spectrum

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Pluto's Atmosphere

  • The Discovery
  • Pluto's Nitrogen Atmosphere
  • Sublimation
  • The Haze Layer
  • Winds Redistribute Frost
  • An Atmospheric "Freeze Out" on Pluto?
  • Measuring the Atmosphere
  • Does Charon Have an Atmosphere?

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The Inside Story

  • Like a Rock
  • Ocean at the Edge of Forever?
  • Inside Charon

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Is Triton Pluto's Twin?

  • A Stray KBO

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The Kuiper Belt

  • Discovering Kuiper Belt Objects
  • Sizes and Colors
  • Atmospheres and Moons
  • Is Pluto a Typical KBO?
  • Jupiter Family Comets

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Comparative Planetology

  • The Outer Planets vs. the Inner Planets
  • Terrestrial Planets, Gas Giants and Dwarf Planets
  • A "Satellite System"
  • Surface Processes on a Dwarf Planet
  • Can Ice Behave Like Rock?
  • Geological Processes
  • Temperature Controls
  • Pluto's Age
  • Origin of Charon

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Is Pluto a Planet?

  • The Pluto Debate
  • What is a Plutino?

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