❄️ DWARF PLANETS
PAGE 1 OF 5 — NOT PLANETS?
NEW RULES
THE 2006 VOTE
For decades schoolchildren memorized nine planets. In 2006 the International Astronomical Union voted on a clearer definition. A planet must orbit the Sun, be round from its own gravity, and have cleared other objects from its orbital path. Pluto failed the third test because it shares space with many other icy bodies in the Kuiper belt. It was reclassified as a dwarf planet, sparking debate that continues today.
🏷️ 2006
The IAU defined dwarf planets in 2006, reclassifying Pluto because it has not cleared its orbit.
RULES!
THREE
☀️ Must orbit the Sun
⭕ Must be round from gravity
⭕ Must be round from gravity
CLEAR
🛤️ Must dominate its orbit
❄️ Pluto shares Kuiper belt
❄️ Pluto shares Kuiper belt
PAGE 2 OF 5 — MEET PLUTO
BELOVED WORLD
HEARTS AND ICE
Pluto is smaller than Earth's Moon but full of surprises. NASA's New Horizons spacecraft flew past in 2015 and sent home images of mountains of water ice, a vast plain called Sputnik Planitia, and a thin atmosphere that freezes and snows onto the surface. Pluto has a giant moon Charon so large that some call them a double world. Whether you call it a planet or dwarf planet, Pluto is a real, complex place.
❤️ 2015
New Horizons revealed Pluto's icy mountains, nitrogen plains, and atmosphere in 2015.
PLUTO!
SURFACE
🏔️ Water ice mountains
💙 Nitrogen ice plains
💙 Nitrogen ice plains
CHARON
🌙 Huge moon, tight pair
🛰️ New Horizons flyby
🛰️ New Horizons flyby
HEART
❤️ Tombaugh Regio plain
🏔️ Icy peaks and valleys
🏔️ Icy peaks and valleys
PAGE 3 OF 5 — FIVE RECOGNIZED
CERES
🪨 Largest asteroid belt object
❄️ Round but not cleared
❄️ Round but not cleared
FAR
🌌 Eris, Haumea, Makemake beyond Neptune
📋 More candidates may join
📋 More candidates may join
THE LIST
CERES TO ERIS
Today the IAU recognizes five dwarf planets: Ceres in the asteroid belt, and Pluto, Eris, Haumea, and Makemake beyond Neptune. Many more candidates wait for confirmation. Eris is about the same size as Pluto and helped trigger the definition debate. Haumea spins so fast it is stretched like an egg and has a ring. Makemake is bright and reddish, covered in frozen methane.
5 WORLDS
The five official dwarf planets are Ceres, Pluto, Eris, Haumea, and Makemake.
FIVE!
PAGE 4 OF 5 — DEBATE GOES ON
FEELINGS
SCIENCE KEEPS TALKING
Some scientists and many fans still call Pluto a planet in spirit. Others say the new rules help us sort worlds fairly. Dwarf planet does not mean unimportant. These bodies hold clues to how the solar system formed and how ice worlds behave. Missions like Dawn at Ceres and New Horizons at Pluto proved they deserve close study.
💬 DEBATE
The Pluto debate continues, but dwarf planet is an official category based on orbital clearing.
TALK!
FOR
📚 Clearer sorting of worlds
🔬 Focus on how orbits work
🔬 Focus on how orbits work
AGAINST
❤️ Pluto feels special to many
🏷️ Labels can confuse kids
🏷️ Labels can confuse kids
SCIENCE
🛰️ Missions still study them closely
❄️ Dwarf does not mean boring
❄️ Dwarf does not mean boring
PAGE 5 OF 5 — DWARF FACTS
WRAP UP
SMALL BUT FASCINATING
Dwarf planets orbit the Sun and are round, but have not cleared their paths. Pluto, Ceres, Eris, Haumea, and Makemake are the five recognized today. Pluto was reclassified in 2006. Spacecraft visits show these worlds are geologically rich. The Kuiper belt and asteroid belt hold many more icy and rocky bodies waiting to be explored.
DWARF!
EXPLORE
🛰️ New Horizons at Pluto 2015
🪨 Dawn visited Ceres
🪨 Dawn visited Ceres
REMEMBER
🪐 KEY FACTS
Dwarf planets orbit the Sun and are round but share their zone with other objects. Five are officially recognized: Ceres, Pluto, Eris, Haumea, and Makemake. Pluto was reclassified in 2006.
🏷️ IAU rules require clearing the orbit
❄️ Pluto lives in the crowded Kuiper belt
🔭 Spacecraft revealed surprising geology
❄️ Pluto lives in the crowded Kuiper belt
🔭 Spacecraft revealed surprising geology
🧠 QUIZ TIME!
❄️ DWARF PLANETS · 5 QUESTIONS
QUESTION 01
What must a dwarf planet do?
QUESTION 02
When was Pluto reclassified as a dwarf planet?
QUESTION 03
Which five worlds are officially recognized dwarf planets?
QUESTION 04
Which spacecraft flew past Pluto in 2015?
QUESTION 05
Where is Ceres located?
0/5
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