Eris

Eris is the furthest dwarf planet from the Sun. It only has one moon, Dysnomia.

Frozen Mystery
Since it is far away from the Sun, very little is presently known about the mysterious dwarf planet. Eris is so sluggish and yet it's so large it takes a mere 557 years to complete one period.

Frozen Elements
Nearly all gases we know of today that exist in Earth's atmosphere would not be liquids, but frozen. The oxygen we breathe today would be frozen, so would methane and ethane, and even chlorine yet.