Eris is the the biggest of the dwarf planets and is the ninth biggest
object that orbits the Sun. Eris was initially called the tenth planet
and then was formally downgraded to a dwarf planet along with Pluto and
Ceres. Eris is named after the Greek goddess of strife and discord but
was originally named 2003 UB313 and unofficially Xena after the the TV
show Xena: Warrior Princess
The surface of Eris is thought to be
made up of methane ice which may sublimate when the planet is closer to
the sun and re-condense when it goes further out.
A year on Eris is 557 Earth years and scientists think that a day might be 26 hours but they may be off by up to 8 hours.
Eris has at least one moon, it is named Dysnomia.
Eris was discovered in 2005 from
photographs taken in 2003. Eris is so new, it is so far away and dim
that there has not been much study of the plant. Scientists have
analyzed the reflected light from Eris to determine its surface makeup.
Eris is three-thousandths the size of Earth and has 9% of the gravitational pull that Earth has.
We have very little data about what
Eris may be made of If it is like Pluto it would have a solid core
surrounded with different ices but more research will need to be done
to know for sure.
in the Night Sky
Eris can only be seen with extremely powerful telescopes and then it is
still just a point of light. So unless you can get some time on a very
large telescope you will probably just have to look at pictures.