Gas might keep the dwarf planet's subsurface ocean from freezing.
Short answer: Because we changed the definition of the word “planet” to better fit its meaning.
Here are some highlights from its journey
The survey also confirmed the existence of two other moons, whose discovery was announced last year
Small, but mighty.
Should we go? Can we afford to go? All this, and more.
A gallery of photos, visualizations, and other pictures of outer space.
The moon won't be this close again for another 18 years
Imagine the space-scuba diving potential
This summer, the mission may get funding to travel to a mysterious rock at the edge of the solar system
The Triton Hopper can propel itself a half-mile into the air
Erupting slush instead of lava
Charon is the real #SuperBloodMoon in latest New Horizons pics
The ocean-filled moon might hold the life we've long searched for in space. And scientists have one shot to reach it.
Short answer: It depends who you ask
The latest and greatest images from the New Horizons mission
So. Many. Things.
New Horizons spacecraft reveals the dwarf planet is slightly larger, has polar ice cap, and more
After nine years and three billion miles, here's what we're learning from it all
New Horizons scientist Leslie Young discusses what to expect from the flyby on Tuesday, and the 28-year wait leading up to it
And he thinks the upcoming flyby will prove it
This year's missions to the outer solar system are set to shake up the planetary family tree
The little white dot is only going to get bigger