Ask a person what Dysnomia refers to... But in addition to being a condition that affects the memory (where people have a hard time remembering words and names), it is also the only known moon of the distant dwarf planet Eris. In fact, the same team that discovered Eris a decade ago – a discovery that threw our entire notion of what constitutes a planet into question – also discovered a moon circling it shortly thereafter. ... The actual size of Dysnomia is subject to dispute, and estimates are based largely on the planet’s albedo relative to Eris. For example,...