What is "eris"

goddess of discord in Greek mythology, from Greek eris "strife, discord," which is of uncertain origin. Watkins suggests PIE root *ere- (3) "to separate, adjoin." Related: Eristic.

Eris (; , "Strife") is the Greek goddess of strife and discord. Her name is the equivalent of Latin Discordia, which means "discord". Eris' Greek opposite is Harmonia, whose Latin counterpart is Concordia. Homer equated her with the war-goddess Enyo, whose Roman counterpart is Bellona. The dwarf planet Eris is named after the goddess, as is the religion Discordianism.

Eris is a genus of the spider family Salticidae (jumping spiders). It is not a large spider and, although it is prone to biting, is not poisonous to humans.

Eris ( minor-planet designation 136199 Eris) is the most massive and second-largest dwarf planet known in the Solar System. It is also the ninth-most-massive known body directly orbiting the Sun, and the largest known body in the Solar System not visited by a spacecraft. It is measured to be in diameter. Eris is 27% more massive than dwarf planet Pluto, though Pluto is slightly larger by volume. Eris' mass is about 0.27% of the Earth's mass.

Eris was discovered in January 2005 by a Palomar Observatory–based team led by Mike Brown, and its identity was verified later that year. It is a trans-Neptunian object (TNO) and a member of a high- eccentricity population known as the scattered disk. It has one known moon, Dysnomia. , its distance from the Sun is , roughly three times that of Pluto. With the exception of some comets, Eris and Dysnomia are currently the second-most-distant known natural objects in the Solar System, the farthest object being V774104 discovered in November 2015 at 103 AU.

Because Eris appeared to be larger than Pluto, NASA initially described it as the Solar System's tenth planet. This, along with the prospect of other objects of similar size being discovered in the future, motivated the International Astronomical Union (IAU) to define the term planet for the first time. Under the IAU definition approved on August 24, 2006, Eris is a "dwarf planet", along with objects such as Pluto, Ceres, Haumea and Makemake, thereby reducing the number of known planets in the Solar System to eight, the same as before Pluto's discovery in 1930. Observations of a stellar occultation by Eris in 2010 showed that its diameter was , not significantly different from that of Pluto. After New Horizons measured Pluto's diameter as in July 2015, it was determined that Eris is slightly smaller in diameter than Pluto.

Eriş is a Turkish name and may refer to:

Eris is a computer simulation of the Milky Way galaxy's physics. It was done by astrophysicists from the Institute for Theoretical Physics at the University of Zurich, Switzerland and University of California, Santa Cruz. The simulation project was undertaken at the NASA Advanced Supercomputer Division’s Pleiades and the Swiss National Supercomputing Centre for nearly eight months, which would have otherwise taken 570 years in a personal computer. The Eris simulation is the first successful detailed simulation of a Milky Way like galaxy. The results of the simulation were announced in August 2011.