Eris Facts

Eris is a dwarf planet beyond the orbit of Neptune (a trans-Neptunian dwarf planet) and is the most distant planet known to us. Eris was one of the first dwarf planets to be discovered. It is almost the same size as Pluto.

Eris Profile

Interesting Eris Facts

  • Eris was discovered on 5th January 2005.
  • It has been named after the Greek Goddess Eris, the personification of strife and discord.
  • It was discovered by a team of scientists consisting of Mike Brown, Chad Trujillo, and David Rabinowitz on 5th January 2005.
  • Eris is 96.4 astronomical units away from the sun.
  • Eris is not always the farthest dwarf planet from the sun as its nearest approach to the sun is closer than Pluto’s farthest approach.
  • It has a radius of 1163 km. This radius was determined with the help of NASA’s New Horizons spacecraft when it reached Pluto.
  • It is the second largest dwarf planet in terms of size and the most massive dwarf planet out of the five in the solar system.
  • If all the objects in the asteroid belt were clubbed together, they could easily fit inside Eris.
  • It is the sixteenth most massive body in the entire solar system and the ninth most massive body orbiting the sun directly.
  • It is a part of the Kuiper Belt and is a Trans Neptunian Object or a TNO.
  • The distance between the sun and Eris is nearly twice the distance between the sun and the dwarf planet Pluto.
  • The range of surface temperatures on the dwarf planet is from -217 °C or -359 °F to -243 °C or 405°F.
  • Eris is known to have one moon called Dysnomia which takes nearly 16 days to complete one orbit around it.
  • Dysnomia has been named after the Greek goddess of lawlessness.
  • It is sometimes referred to as the tenth planet of the solar system.
  • It is sometimes known as the Twin of Pluto.
  • Eris and Dysnomia are two of the farthest known objects of the solar system.
  • Eris has been mentioned in a lot of books, TV shows, films and even video games.

Eris

Eris is one of the five recognized Dwarf planets of our solar system. Eris and its moon Dysnomia are two of the farthest objects of the solar system known to mankind.

Obviously because of its distance, not much is known about this dwarf planet or its moon. But a significant amount of information is available about the dwarf planet thanks to advanced telescopes and modern technology. The details about this dwarf planet and its moon have been explained in this article.

A dwarf planet is a celestial body or object that does not fall into the category of either planets or natural satellites. For an object to be classified as a planet, it has to satisfy three criteria. The object must be orbit the sun directly. It should have a considerable mass. Lastly, it must have cleared the space around it that is they must be gravitationally influential.

Usually, any celestial body that does not meet one of these requirements is considered as a dwarf planet. In general, dwarf planets do not need the third requirement to be considered as a planet.

The term ‘dwarf planet’ was adopted in the year 2006 when astronomical objects were discovered beyond the orbit of the planet Neptune. According to the International Aeronautical Unit or IAU, there are five recognized dwarf planets in the solar system. They are Ceres, Pluto, Haumea, Makemake, and Eris.

History

Eris was discovered by a team of scientists consisting of Mike Brown, Chad Trujillo, and David Rabinowitz on 5 January 2005. It was discovered the same day as Makemake. Haumea was discovered just two days before Eris and Makemake. The discovery of the dwarf planets was officially announced on 29th of July 2005.

Earlier images of the dwarf planet date back to 3 September 1954. Eris’ only moon, Dysnomia, was discovered in the month of October the same year.

Eris has been named after a figure from Greek mythology. It was the name of the Greek Goddess Eris, who was the personification of strife and discord. The name was officially assigned to the dwarf planet on the 6th of September 2006. Its moon Dysnomia has been named after the Greek Goddess of lawlessness. The discovery of Dysnomia was announced in September 2005.

Initially it was not clear whether Eris was a dwarf planet or a minor planet. Since different rules of nomenclature apply to minor planets and dwarf planets it was difficult to designate Eris.

In common terms, the dwarf planet was quite often referred to as Xena. This name came from the name of the titular character of a series. Initially, Eris was described as the tenth planet of the solar system as it was thought to be larger than Pluto.

Eris was officially categorized as a dwarf planet when the rules to qualify as a planet were ordered by the International Astronomical Union or the IAU.

Eris is a member of the Trans Neptunian region called the Kuiper Belt which is similar in appearance to the asteroid belt and consists of several smaller celestial bodies. Hence it can be estimated that the formation of this dwarf planet took place really 4.5 million years ago along with the formation of the entire solar system.

Appearance

The dwarf planet Eris has a greyish appearance. This could be because of the presence of frozen methane on its surface. This also results in Eris looking very foggy from a distance. It cannot be seen directly from the naked eye as it is very far away from the Earth. It requires advanced telescopes to view and observe this dwarf planet. Not much is known about Eris’s only moon, Dysnomia.

Size

It has a radius of 1163 km or 722 miles. The radius of the earth is nearly one fifth of the radius of the earth. It is very much similar to Pluto in terms of size. This is believed to be almost perfectly spherical in shape and about 27% denser than Pluto which gives it more Mars.

It is sometimes known as the Twin of Pluto because it shares many properties that are similar to Pluto. This includes size, mass and probably even composition.

Surface & Composition

The surface of the dwarf planet is extremely reflective in nature. It is believed to reflect back nearly 96% of the total light that it receives. This makes it one of the most reflective bodies in the entire solar system. The surface of Eris is believed to be very much similar to the surface of Terrestrial planets or even the dwarf planet Pluto with whom it shares several similar properties.

The surface is rocky and cold. The surface may contain nitrogen in abundance with water ice and frozen methane. It may also have a very thin layer for a mantle. According to scientists, the surface temperatures on the dwarf planet could range from -217 °C or -359 °F to -243 °C or -405 °F.

Not much is known about the internal structure of Eris or its moon Dysnomia.

Orbit & Rotation

Eris takes about 558 years on Earth to complete one orbit around the sun. This time duration is extremely large as Eris is at a great distance from the sun. On an average, it is nearly 96.4 astronomical units (AU) which is around 14,062,199,874 km away from the sun.

Orbit of Eris
Orbit of Eris. Pic courtesy: wikimedia

The distance between the sun and Eris is nearly 3 times larger than the distance between the sun and the dwarf planet, Pluto. Eris and its only moon, Dysnomia, are the farthest known objects of the solar system, keeping aside the long-period comets. Eris is so far away from the sun that sunlight takes approximately 5 hours and 15 minutes to reach the dwarf planet.

This dwarf planet has a highly eccentric orbit. At its perihelion, it comes very close to the Sun it comes at a distance of nearly 39 astronomical units. Eris takes 26 hours to rotate about its own axis once. Interestingly, the closest point of Eris to the sun is closer to the sun than the farthest point of Pluto. Hence this isn’t always the farthest dwarf planet from the sun.

Magnetic Field

It is not known whether or not Eris has a magnetic field.

Atmosphere

Not much is known about the atmosphere of Eris, but it is assumed to be very thin. All so much like most of the other Trans-Neptunian Objects (TNO), the atmosphere of the dwarf planet collapses as it goes away from the Sun and thaws when it comes close to it.

Moons

Eris with Moon Dysnomia
Eris with Moon Dysnomia: Pic : https://upload.wikimedia.org/wikipedia/commons/d/d4/Artist%27s_impression_dwarf_planet_Eris.jpg

Eris has one moon Dysnomia. discovered in 2005, and was named Dysnomia, after the daughter of the goddess Eris.

Dysnomia

Dysnomia was discovered in 2005 only a few months after its parent Eris was discovered. It was named Gabrielle was also a character from TV the sidekick of Xena which was the nickname for Eris. It has been named after the Greek goddess of lawlessness. Dysnomia cannot be seen from the earth with the naked eye. It is also a little difficult to see the moon from the telescope as it is very small and dim.

This moon takes nearly 16 days to complete one Orbit around Eris. Dysnomia and its parent Eris are two of the farthest known objects in the entire solar system. Hence not much is known about Dysnomia and its properties including its internal structures.

Eris Exploration

Eris has never been visited by any spacecraft. However, it was observed by NASA’s New Horizons spacecraft when it reached its apparent neighbor Pluto. The spacecraft helped in determining the size and the mass of the dwarf planet which turned out to be pretty close to what had been previously estimated using other techniques.

No human being has ever visited Eris. It would be very difficult to build a spacecraft and send humans to Eris as the spacecraft would take several years to reach the dwarf planet.
However human missions to father planets may become possible in the future.

Life on Eris

No evidence of life has been found on it up till now. The first and the most obvious reason for this could be its great distance from the Sun. This could also be because Eris has a very cold surface and the conditions which are too extreme for the presence of life and hence it is less likely that life could exist on this dwarf planet.

Eris in Pop Culture

Eris was earlier named as Xena and when its moon was discovered it was named Gabrielle (who was the sidekick of the TV character Xena).

Timeline

  • 2005: Eris is discovered and nicknamed ‘Xena’
  • 2005: Xena’s moon, Dysnomia is discovered
  • 2006: Xena is declared a dwarf planet
  • 2006: Xena is renamed ‘Eris’

References

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