While we were in school, we studied that our Solar System is made up of nine planets, namely Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Pluto. However, we may have to unlearn this knowledge. In the year 2006, the International Astronomical Union started using another method of classifying stellar objects. This classification believed that 3 types of stellar objects were present in the Solar System, namely planets, dwarf planets and bodies of Solar System.
Based on this classification, Pluto was assigned as a dwarf planet and no longer considered as a planet. While dwarf planets do orbit around the sun, they do not have sufficient force to overcome forces and form a round shape. Also, they are unable to clear the path of their orbit of objects that could be satellites of other planets. Today, there are 5 dwarf planets that we know of. They are Eris, Pluto, Haumea, Makemake and Ceres. Out of all the known dwarf planets, the largest is Eris, while the smallest is Ceres.
Eris was first spotted in the year 2003, but it was confirmed only in the year 2005, in January by an astronomer from California Institute of Technology named Michael Brown. It is the most distant stellar object to be discovered orbiting the Sun.
One being discovered, Eris was first named 2003 UB313. Then it earned the nickname Xena, and finally in September 2006, the dwarf planet was officially called Eris by the International Astronomical Union.
The name of the dwarf planet was taken from Greek mythology. Eris was the goddess of warfare and conflict. She was responsible for bringing hatred, anger and jealousy amongst men which caused them to fight one another. The name was carefully selected as the discovery of this dwarf planet was plagued with controversies. The astronomy community was happy with the way Eris was classified. Hence, it got an appropriate name.
Eris has a slightly bigger diameter compared to Pluto at 2,400 kilometers. It around 97 AU from the Sun and takes around 577 years to complete an orbit around the Sun. The temperature on Eris varies from -217 degrees Celsius to -243 degrees Celsius.
Scientists believe that Eris’ outer layer is made up of frozen methane that has managed to seep its way into the insides. As not too much radiation from the Sun reaches the dwarf planet, the surface of Eris is yellowish in color. Till now, scientists have been able to discover just one moon revolving around Eris and they have named the moon Dysnomia, who in Greek mythology was Eris’ daughter. Dysnomia takes around 2 weeks to orbit around Eris.
In order to see Eris, you need an extremely powerful telescope. You will not be able to see this planet with a pair of binoculars or naked eyes.