Universe Guide


Eris is a Kuiper Belt object, a large rock that orbits round outside the orbit of Neptune. It has been categorised as a Trans-Neptunian object.

Eris was discovered on 21st October 2003 by M. E. Brown, C. A. Trujillo and D. Rabinowitz . Its takes 25.9 Hours to do a full rotation period.

The absolute magnitude of the object is -1.1 which is the brightness of the object. A higher absolute magnitude means that the object is faint whereas a very low number means it is very bright.

The Aphelion of the object is 97.471 A.U. which is the point in the orbit that is furthest from the object that it is orbit. At this point, it will then return back to the orbit target. The Perihelion of the object is 38.019 A.U. which is the point in the orbit that is closest to the object that it is orbit around. The Longitude of Ascending Node of the object is 35.9 degrees. The Argument of Perihelion is 151.7. It is the angle along the orbit of a planet or other Solar System object as measured from the ascending node (analogous to right ascension and longitude) Ref:Hawaii.

The mean anomoly is 205.4, is the angular distance of the planet from the perihelion or aphelion. Ref:Dictionary.The Semi-Major Axis of the orbit is 67.745, which is the furthest point from the centre to the edge of an elliptical point.

The orbital inclination, the angle at which Eris orbits in relation to the orbital plane is 44.1 degrees. The orbital eccentricity is 0.439, it is the degree at which Eris orbits close to a circular (0) orbit as opposed to an elliptical (1) orbit.

Eris and Pluto

Eris when it was discovered was believed to be larger than Pluto, the then ninth planet. Since Eris was discovered, Pluto was downgraded to that of dwarf planet because it doesn't clear the neighbourhood already. A lot of people call that reason a fudge. At one time, the kuiper belt Object was believed to be larger than Pluto. New analysis shows that Eris is about the same size as Pluto. Space

The search is on for another planet that is believed to be even further out than both Eris and Sedna. The evidence for this is that most of the distant Kuiper Belt Objects orbits are angled away from a certain area of the sky. The planet is believed to have a mass 10x that of the Earth and orbit 20x further out than Neptune. Neptune is about 30 A.U., the planet would be 300 A.U. At that distance, it would not be in the Oort cloud which is a distance of about 5,000 to 100,000 based on Google figures.

Distance to Eris

Eris is more than twice the distance from the Sun to Pluto and there are no plans at the present to send a probe that far out. It took about nine years for New Horizons mission to reach Pluto.National Geographic.

A mission to Eris would take an estimated 25 years (rounded up) to travel there using a Jupiter assistance in April 2032 or April 2044. Ref: Harvard Unless you're very young, you'll probably not get to see what Eris looks like if we could only see it by getting up close. It took 85 years for us to see what Pluto looked like.

The only way we'll be able to learn anything new about the planet at the moment is if we studied it from our Earth based telescopes (including those in orbit). If we ever discover how to travel faster than light, people would then be all over the planet.

Sedna was for a long time, the record holder of being the furthest point from the Sun within the solar system. Sedna is 86 Astronomical Units (1 Astronomical Unit is equal the distance from the Sun to the Earth) Ref: Wiki and Eris is 96.4 Astronomical Units. Eris is roughly three times the distance of Pluto. Ref: The Planets,

Xena, unofficial name for Eris

When Michael Brown and his associates discovered Eris, it was called Xena after the television character Xena, Warrior Princess. the moon of Eris was named Gabrielle after the character that accompanied Xena on her adventures. The I.A.U. didn't approve of the name and therefore named it Eris. Gabrielle was named Dysnomia. It took a long time for the dwarf planet to be given a name. Eris was chosen finally after a year and half. Eris was the goddess of discord and strife.

Path of Eris Orbit

If the white lines are above, then the path of the object is under the ecliptic. If the white lines are below, the path is above the ecliptic. This refers to the Inclination of the object. The image was created using N.A.S.A. Solar System Dynamics.

Path of Eris Orbit

Eris Facts

TypeKuiper Belt Object
Asteroid TypeCentaur
Date of Discovery21st October 2003
DiscovererM. E. Brown, C. A. Trujillo and D. Rabinowitz
Rotation Period25.9 Hours
Absolute Magnitude-1.1
Aphelion (Furthest)97.471 A.U.
Perihelion (Nearest)38.019 A.U.
Longitude Of Ascending Node35.9
Argument of Perihelion151.7
Mean Anomoly205.4
Semi-Major Axis67.745
Orbital Inclination (degrees)44.1
Orbital Eccentricity0.439

Comments and Questions

There's no register feature and no need to give an email address if you don't need to. All messages will be reviewed before being displayed. Comments may be merged or altered slightly such as if an email address is given in the main body of the comment.

You can decline to give a name which if that is the case, the comment will be attributed to a random star. A name is preferred even if its a random made up one by yourself.

This website is using cookies. More info. That's Fine