In our Solar System there are eight planets, among them the Earth, all revolving around the king star. But few know that there are also five dwarf planets. What are they and why are they called that?
The dwarf planets of the Solar System are those celestial bodies that orbit around the Sun and have a spherical shape.
They are called that because they do not meet all the criteria established by the International Astronomical Union to be considered part of the group of “traditional” planets, so to speak. At the end, we will talk about What is the criterion they are missing? to be part of the main group.
The 5 dwarf planets Of the solar system:
- Ceres, the largest in the asteroid belt, located between Mars and Jupiter.
- Pluto, the best known, which was “demoted” to a dwarf planet in 2006.
- Eris, which is larger than Pluto, discovered in 2005.
- makemake, found in 2005, which is similar to Pluto in size and composition.
- Haumea, Discovered in 2004, with an elongated shape: it is the fastest of the dwarf planets.
Evidently, none have the capacity to generate life, as the Earth does.
The criteria established by the International Astronomical Union to be considered planets are the following:
- To orbit Around the sun.
- Have sufficient mass so that its own gravity overcomes the cohesive forces of the solid body, so that it acquires an almost spherical shape.
- To have cleared its orbital neighborhood.
In the case of dwarf planets, do not meet the third criterion, since they share their orbit with other celestial objects. An example: Pluto shares its orbit with the Kuiper Belt, which we previously talked about on FayerWayer as a site where the so-called Planet Nine possibly exists.
The reclassification of Pluto as a dwarf planet It resulted in an important change in the understanding of the Solar System. Until that time, Pluto was the ninth planet in the Solar System; but the discovery of Eris, an object larger than Pluto, led the scientific community to reconsider its status.
That is why, in 2006, the UAI approved a new definition of a planet that reclassified Pluto as a dwarf planet. This decision was controversial, but ended up being accepted by the majority of scientists.