Dwarf Planets Quiz

The Solar System's Dwarf Planets

• Our solar system consists of eight conventional planets, including four rocky terrestrial planets and four gas giants.
• Beyond the eight planets lie dozens of small icy worlds known as minor planets, including Pluto, which was reclassified as a dwarf planet in 2006.
• There are almost 800,000 known minor planets in the solar system, archived by the Minor Planet Center.
• The terminology for minor planets, planetoids, and asteroids has become more complicated due to discoveries in the outer solar system, leading to the need for clarifications.
• In 2006, the International Astronomical Union amended the definition of a planet, adding a criterion that a planet must clear out its orbital path.
• Pluto lost its planetary status due to not meeting the revised definition and was reclassified as a dwarf planet.
• The IAU then reclassified the term "minor planet" into two new sub-categories: dwarf planets and small solar system bodies (SSSBs).
• Dwarf planets are nearly spherical but don't dominate their surrounding space, while SSSBs encompass anything else that isn't a comet.
• The first dwarf planet ever discovered and visited is Ceres, located within the asteroid belt between the orbits of Mars and Jupiter.
• Ceres was initially mistaken for a comet and then for a planet before being reclassified as a dwarf planet due to its large size and mass compared to other objects in the asteroid belt.
• Ceres was discovered in 1801 by Giuseppe Piazzi and named after the Roman goddess of corn and harvests.
• Ceres is about 1000 kilometers in diameter and accounts for about a third of the asteroid belt's total mass.

The Solar System's Dwarf Planets and Kuiper Belt

• In 2015, NASA's Dawn spacecraft made flybys of the dwarf planet Ceres, sending back detailed images and clues about its composition.
• Ceres is composed of rock and water ice, with a core and mantle thought to have a layer of ice, potentially holding more water than Earth in solid form.
• It is believed that Ceres may have had an ocean of magnesium salt water on its surface billions of years ago.
• The Kuiper Belt, located beyond all eight planets, is a vast, densely populated region consisting of icy objects and debris.
• The Kuiper Belt is home to hundreds of millions of cometary nuclei, thousands of objects larger than 100 kilometers in diameter, and cold dwarf planets.
• Pluto, a Kuiper Belt object and dwarf planet, was visited by NASA's New Horizons mission in 2015, revealing its detailed landscape and complex features.
• Pluto's surface temperatures can fall as low as -240 degrees Celsius, leading to the formation of frozen nitrogen ice sheets.
• Pluto's heart-shaped region, Tombaugh Regio, is a smooth plane of volatile ice sheets with evidence of convection currents below the surface.
• The debate over the definition of a planet was prompted by the discovery of new dwarf planets, including Eris, Haumea, and Makemake, in the Kuiper Belt between 2003 and 2005.
• Eris, the second largest dwarf planet in the solar system, was initially set to be classified as the 10th planet but was later reclassified as a dwarf planet, prompting the addition of a third criterion in the definition of a planet.
• Haumea, a dwarf planet, has an elongated egg shape and is thought to be the largest constituent of a collection of trans-neptunian objects left over from a large collision of debris.
• Makemake, another dwarf planet, was discovered in 2005 and is the third dwarf planet discovered by Mike Brown.

The Solar System's Dwarf Planets

• Our solar system consists of eight conventional planets, including four rocky terrestrial planets and four gas giants.
• Beyond the eight planets lie dozens of small icy worlds known as minor planets, including Pluto, which was reclassified as a dwarf planet in 2006.
• There are almost 800,000 known minor planets in the solar system, archived by the Minor Planet Center.
• The terminology for minor planets, planetoids, and asteroids has become more complicated due to discoveries in the outer solar system, leading to the need for clarifications.
• In 2006, the International Astronomical Union amended the definition of a planet, adding a criterion that a planet must clear out its orbital path.
• Pluto lost its planetary status due to not meeting the revised definition and was reclassified as a dwarf planet.
• The IAU then reclassified the term "minor planet" into two new sub-categories: dwarf planets and small solar system bodies (SSSBs).
• Dwarf planets are nearly spherical but don't dominate their surrounding space, while SSSBs encompass anything else that isn't a comet.
• The first dwarf planet ever discovered and visited is Ceres, located within the asteroid belt between the orbits of Mars and Jupiter.
• Ceres was initially mistaken for a comet and then for a planet before being reclassified as a dwarf planet due to its large size and mass compared to other objects in the asteroid belt.
• Ceres was discovered in 1801 by Giuseppe Piazzi and named after the Roman goddess of corn and harvests.
• Ceres is about 1000 kilometers in diameter and accounts for about a third of the asteroid belt's total mass.