Scientists decided to create a new classification for celestial objects in 2006.
This classification was announced by the IAU (International Astronomical Union) and addressed the need to further identify planets in a subcategory known as dwarf planets.
|Name||Discovered||Diameter||Distance from the Sun (times Earths distance)||Orbit Period (Earth Years)|
|Ceres||1801||950 km||2.8||4.6 years|
|Pluto||1930||2,372 km||39.5||248.0 years|
|Haumea||2003||1,960 km - 1,518 km × 996 km||43.1||283.3 years|
|Makemake||2005||1,434 km × 1,422 km||45.3||309.9 years|
|Eris||2003||2,326 km||68||560.9 years|
Another area that makes dwarf planets different is that regular planets have cleared the neighborhood around their orbits, whereas dwarf planets have not always done so.
Since the announcement, there have only been five celestial bodies defined as dwarf planets in our solar system: Ceres, Pluto, Haumea Makemake, and Eris.
At one time, Pluto was considered to be our 9th planet, and then it was downsized to a dwarf planet.
All of the dwarf planets except Ceres are located in the outer solar system near or in the Kuiper belt. Ceres is inside the asteroid belt that is between Jupiter and Mars’ orbit.
There are other objects that are waiting to become officially classified, and it’s believed that there may be around 10,000 dwarf planets in our solar system.
Dwarf planets are also smaller in size, and since they are so far out in our solar system, only some information has been gathered.
The New Horizons spacecraft mission is the single mission that collected the most data, including excellent images of Pluto.
Most of the pictures that we have had were blurred, without any detail. New Horizons cruised by Pluto, its moons, and various objects in the Kuiper belt.
It was once thought that Pluto was the largest of the dwarf planets but thanks to the New Horizons mission, we have learned that the largest dwarf planet is Eris.
Eris is only a little bit bigger than Pluto at 1,445 mi in diameter. Eris takes around 561.4 Earth years to complete an orbit around the sun.
The smallest of the dwarf planets include Makemake, Haumea, and Ceres. The orbital path of both Pluto and Eris actually cross each other.
One of the important things to note is that Pluto had been listed as the ninth planet in our solar system since 1930.
For some strange reason, people had an affection for this little planet and when it was demoted, there was a worldwide outcry.
Children, especially, wrote letters to astrophysicist Neil deGrasse Tyson, to register their complaints.
It does show that people had a connection with that little planet that was both wonderful and confusing.