Dwarf Planets

By: Matt McQuaid

Elysian Records

Duskus - Outer Space by Elysian Records

Driving Question

What connections can you see between how the International Astronomical Union classifies planets, dwarf planets, and small solar system objects now and in the past.

The IAU

  • Founded in 1919.

  • 11447 members in the IAU, 96 countries participate in research.

  • Mission is to promote and safeguard the science of astronomy in all the aspects through international cooperation.
  • 96 countries participate

The Classification of Planets

How planets were previously classified was much simpler back then than it is now. They classified them by: Color Surface, texture was looked at, Elements like air, fire, earth, and water. The Nebula around it also was used to classify them


Now planets are classified more complexly. Now there's more tedious classifications like Inferior planets - inside Earth’s orbit Superior planets - outside Earth’s orbit Inner planets - inside the asteroid belt Outer planets - outside the asteroid belt Gas giants - sharing the gaseous structure (like Jupiter)

  • Planet originally meant wanderer.

  • Planet: a celestial body that orbits the Sun.

  • Classify: arrange in classes or categories according to stored qualities and characteristics.

  • A new distinct class of objects called dwarf planets was also decided on. It was agreed that planets and dwarf planets are two distinct classes of objects.

The Discovery of Pluto

Nearly 80 years ago Clyde Tombaugh discovered Pluto. He found Pluto by comparing 2 plates of pictures of Outer space. He switched back and fourth between the 2 showing a region in the constellation of Gemeni. As he switched back and fourth between them he saw a small object. The object Tombaugh discovered was named Pluto a name officially adopted by the American Astronomical Society

Dwarf Planets

Classification

  • A new distinct class of objects called dwarf planets was also decided on. It was agreed that planets and dwarf planets are two distinct classes of objects.

  • Currently five objects accepted as dwarf planets: ceres, pluto, makemake, eris, and haumea, previously known as 2003 UB313.

Small Solar System Bodies

  • SSSBs used to be called minor planets, but the name later changed.

  • The IAU classifies all objects orbiting the Sun that are too small to satisfy the definition of planet or dwarf planet as SSSBs.

  • Planet, dwarf planet, and SSSBs are all officially new definitions of the IAU.
  • Small solar system bodies (SSSB) include objects like: comets, asteroids, small planetary satellites, Triton, Pluto, Charon, and interplanetary dust.