On January 5, 2005, astronomers at NASA discovered Eris, the second-largest dwarf planet in the solar system. Eris is just slightly smaller than Pluto, and it orbits the sun about three times farther ...

For More Webcasts: http://www.nasm.si.edu/webcasts/archive.cfm?siref=YouTube&video=PlutoErisDwarfPlanets Pluto, Eris, and the Dwarf Planets of the Outer Solar System ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. An illustration of confirmed dwarf planets and their moons. From left to right: Pluto (with ...

Pluto, once considered the ninth planet, was reclassified as a dwarf planet in 2006 because it shares its orbital path with ...