Pluto

Recent observations that a tiny object in our solar system is a likely dwarf planet has some planetary scientists grumbling again about Pluto's demotion to that status.

NASA's New Horizons spacecraft is now more than halfway from Pluto, which it famously flew past in July 2015, to its next flyby target: a distant object known as 2014 MU69.

After more than a decade of controversy, the debate over the icy world's demotion to "dwarf planet" status shows no sign of stopping

A group of planetary scientists is making the case for a new definition of a planet; this one would include Pluto and most moons. Here's why these researchers think the new definition is better.

Pluto's famous heart-shaped feature is on the road to getting an official name, nearly two years after its discovery.

The New Horizons probe that flew by Pluto in 2015 sent back data suggesting this icy world possesses organics, water and energy, or what scientists consider the necessary ingredients for life.

NASA's New Horizons spacecraft performed a brief engine burn Wednesday (Feb. 1) in preparation for its 2019 flyby of a small, distant object known as 2014 MU69.