When astronomers found a large world farther out than Pluto, it became one of the final nails in the coffin of our ninth ...

The dwarf planet Sedna, discovered in late 2003, was the first known ETNO. Following Sedna's discovery was speculation that its odd orbit must imply the existence - and influence of - of some ...

The discovery of the 2012 VP113 object lent weight to the Sedna hypothesis because Sedna and 2012 VP113 had similar orbits.

Sedna has been cited as possible evidence for ... nine planets—which it had before Pluto’s demotion in 2006—the discovery of a distant Earth-mass planet would have profound implications ...