Dwarf Planets
- Ishita Chintala
- Oct 3, 2022
- 3 min read
Dwarf planets are distant worlds that do not resemble any familiar planets, such as Mercury or Venus. In fact, dwarf planets can be observed in any shape and size, and they are located in different regions, such as the asteroid belt and the kuiper belt. In this blog, we’ll explore what distinguishes a planet from a dwarf planet, examples of dwarf planets, and detailed descriptions of each dwarf planet listed.
What is a dwarf planet?
In our planets blog, we described planets to be, “a celestial body that essentially wanders in outer space around a host star”. While dwarf planets are also celestial bodies that wander in outer space around a host, they are different in several ways, which will be explained below.
According to NASA (2021), planets in our solar system must meet the following requirements:
Orbit the sun
Have a spherical shape
Clear its orbit of any similarly sized objects
Dwarf planets are any bodies in space that orbit the sun and have a spherical shape, but the key difference between them and a planet is that they do not meet the third requirement, which is to clear its orbit of any similarly sized objects.
Pluto
Pluto has been referred to as a planet until 2006, which is when NASA classified it to be a dwarf planet instead. The reason for this “demotion” (as some would say) is because Pluto has not cleared its orbit of similar-sized objects, which is the third requirement to be a planet. Despite this, Pluto still stands out in many aspects- one being that it is the first object to be discovered in the Kuiper Belt. Another cool fact about Pluto is that one Plutonian year is 248 earth years, and one Plutonian day is 6.4 earth days (NASA 2021)! Pluto has several moons, which are Charon, Nix, Styx, Kerberos, and Hydra. Pluto is still amazing in its own way, even if it’s not a planet!
Ceres
Ceres is a dwarf planet located in the asteroid belt. It's also the biggest object in the region, taking up a third of the belt’s mass! While Ceres takes up a lot of the asteroid belt’s mass, Pluto is still "14 times more massive" (NASA, 2022). Ceres is the first object to be discovered in the asteroid belt and the first dwarf planet to be visited by a spacecraft in said region. In 2006, Ceres was deemed a dwarf planet rather than an asteroid due to the fact that it has a significantly bigger mass and has distinct features that separates it from the asteroids that surround it.
Makemake
Makemake is the second brightest object in the Kuiper belt, after Pluto. One day on Makemake is about 22 hours, and one year is about 305 Earth years. Currently, the dwarf planet does not have any moons of its own. Makemake and Eris were two significant dwarf planets that "prompted the International Astronomical Union (IAU) to reconsider the definition of a planet and to create the new group of dwarf planets” (NASA, 2021).
Haumea
Haumea is named after the Hawaiian goddess of fertility. One day in Haumea is only 4 hours. The fastness of Haumea’s orbit is what gives it its distorted shape. One year is 285 Earth years. Haumea has two moons: Namaka (named after the water spirit in Hawaiian mythology) and Hi’iaka (named after the goddess of Hula dancers and island of Hawaii). What’s fascinating about this dwarf planet is its rings; in fact “Haumea is the first known Kuiper Belt Object to have rings” (NASA, 2021).
Eris
Last but not least, Eris, named after the Greek goddess of discord, is the largest dwarf planet in our solar system. In fact, it was so big, the IAU had to reconsider the definition of a planet in 2006. Eris has a moon named “Dysnomia”. One day on Eris is about 26 hours, and one year is 557 Earth years.
Thank you for reaching the end of this blog. Be sure to check out our CBSS series on Instagram for more information on each dwarf planet! Stay tuned for our next blog post. Until then, keep gazing skywards!
Bibliography
Ceres. (2022). NASA Solar System Exploration. Retrieved September 29th, 2022, from
Eris. (2021). NASA Solar System Exploration. Retrieved September 29th, 2022, from
Haumea. (2021). NASA Solar System Exploration. Retrieved September 29th, 2022, from
Makemake. (2021). NASA Solar System Exploration. Retrieved September 29, 2022, from
Planets. (2021). NASA Solar System Exploration. Retrieved September 29th, 2022, from
Pluto. (2021). NASA Solar System Exploration. Retrieved September 29th, 2022, from
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