Since its discovery in 1930, until 2006, Pluto was counted as the ninth planet in the solar system. In 2006, the International Astronomical Union reclassified it as a ‘dwarf planet’, and our ...

A few decades ago, the Solar System had nine planets, but in 2006 the International Astronomical Union reclassified Pluto as a dwarf planet. Shortly thereafter, reports emerged about the possible ...

Aside from the solar system once again having nine planets—which it had before Pluto’s demotion in 2006—the discovery of a distant Earth-mass planet would have profound implications for ...