Eris

Erisi (alama: 16px|⯰; pia (136199) Erisi au 136199 Erisi) ni sayari kibete kubwa inayojulikana katika mfumo wa Jua letu.
 Tabia ze Erisi 
Njia yake ya kuzunguka jua ni nje ya njia ya Pluto. Eros inaonekana ina angalau mwezi mmoja unaoitwa Dysnomia. Makadirio ya kipenyo chake ni 2400 km ambacho ni kikubwa kidogo kuliko Pluto. Inazunguka jua katika muda wa miaka 556.7 ya dunia. Umbali wake na jua ni mara 97 umbali wa dunia yetu. Kutoka Erisi hata jua letu laonekana kama nyota ndogo tu.

 Kutambuliwa kwa Erisi 
Erisi ilitambuliwa 2005 na wanaastronomia walioongozwa na Dr. Michael E. Brown kwenye paoneaanga Mount Palomar (Marekani). Walichungulia picha za anga zilizopigwa mwaka 2003 wakatambua nukta ya anga lililobadilika mahali. 

 Erisi ni chanzo cha utaratibu wa "Sayari Kibete" 
Kutambuliwa kwa Erisi kulisababisha wanafalaki kuanzisha kitengo kipya cha "sayari kibete". Brown aliwahi kutangaza Erisi kuwa sayari ya kumi ya jua letu. Lakini wataalamu wengine waliona uwezekano mkubwa ya kwamba magimba mengine ya kufanana na Erisi yatapatikana karibuni. Maana ya neno "sayari" kwa kulingana na sayari za ndani ilihofiwa kutavurugika. Hivyo utaratibu wa sayari kibete ulianzishwa.

Hivyo Erisi ilikuwa sababu ya kushushwa kwa cheo cha Pluto ambayo ni ndogo kuliko Erisi.

 Viungo vya Nje 
 [http://www.gps.caltech.edu/~mbrown/planetlila/ Michael Brown's webpage about 
 [http://www.gps.caltech.edu/~mbrown/planetlila/moon/ Tovuti ya Brown kuhusu mwezi wa Eris 
 compiled list of data
 MPEC listing 
 Java 3D orbit visualization
 Spaceflight Now article
 Slacker Astronomy Interview With Co-Discoverer Trujillo
 NASA - new planet discovered
 Trans-Neptunian Object mp|2003 UB|313 — IAU statement regarding the planetary status of Eris
 Simulation of mp|2003 UB|313's orbit — mp|2003 UB|313 is in a 17:5 resonance with Neptune
 Keck observatory page about the discovery of mp|2003 UB|313's moon
 Parade Magazine on the spacecraft New Horizons
 M. E. Brown et al., Satellites of the largest Kuiper belt objects, Astrophysics Journal Letters, 25 Desemba 2005 preprint

 Habari magazetini 
 Tenth planet discovered in outer solar system - NewScientistSpace.com
 Astronomers Discover "10th Planet"  - Sky & Telescope article
 Tenth Planet Discovered - Astronomy Magazine article
 LARGER THAN PLUTO! 10th Planet Discovered? - Planetary Society
 Tenth planet found! - spaceflightnow.com
 Object Bigger than Pluto Discovered, Called 10th Planet - space.com
 Astronomers detect '10th planet' - BBC News
 You Call That a Planet? How astronomers decide whether a celestial body measures up.  - Slate.com
 Hubblesite:Revised diameter (April 2006)
 A Dwarf Planet Is Named: Eris - New York Times

Eris