Pluto – which is smaller than Earth’s Moon – has a heart-shaped glacier that’s the size of Texas and Oklahoma. This fascinating world has blue skies, spinning moons, mountains as high as the Rockies, and it snows – but the snow is red. Pluto takes an oval-shaped path with the Sun nowhere near its center. What's more, its path is quite tilted compared to the planets.

On July 14 2015, NASA’s New Horizons spacecraft made its historic flight through the Pluto system – providing the first close-up images of Pluto and its moons and collecting other data that has transformed our understanding of these mysterious worlds on the solar system’s outer frontier. In the years since that groundbreaking flyby, nearly every conjecture about Pluto possibly being an inert ball of ice has been thrown out the window or flipped on its head.

Pop Culture

When Pluto was reclassified in 2006 from a planet to a dwarf planet, there was widespread outrage on behalf of the demoted planet. As the textbooks were updated, the internet spawned memes with Pluto going through a range of emotions, from anger to loneliness. But since the release of New Horizons images showing a very prominent heart-shaped feature on the surface, the sad Pluto meme has given way to a very content, loving Pluto that would like to once again be visited by a spacecraft.

The Disney cartoon character Pluto, Mickey's faithful dog, made his debut in 1930, the same year Tombaugh discovered the dwarf planet. There is speculation that Walt Disney named the animated dog after the recently discovered planet to capitalize on its popularity, but other accounts are less certain of a direct link.