How many dwarf planets are there in our solar system? The recent discovery of 2017 OF201 makes the tally anywhere between ...

At the far reaches of our Solar System lies Pluto, a mysterious world shrouded in shadows and icy terrain. NASA’s latest ...

Pluto's status has been a heated debate for decades with arguing over a dwarf planet classification. Here's what international standards say in 2023.

When did Pluto stop being a planet, and why? Pluto was always in a tough spot when it came to being a planet. Just 1,477 miles across, it's only one-fifth the diameter of Earth.

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists — including hints about how the solar system formed.

The James Webb Space Telescope (JWST), operated by NASA, has uncovered intriguing new details about Charon—Pluto’s largest ...

Pluto was discovered in 1930 in Arizona, but in 2006 scientists decided to cut Pluto from the planetary line up. Here is why Pluto isn't a planet.

Arizona Gov. Katie Hobbs signed a bill making Pluto the official state planet. It was discovered at an observatory in Arizona, but was downgraded to a dwarf planet in 2006.

But why isn't Pluto considered a planet anymore? It starts with the definition of a planet — or lack thereof. Before 2006, there weren't strict criteria for a planet.

Pluto, officially a dwarf planet, has surprising complexity on its surface. While certainly a world, not everyone agrees it is a planet.

Yet, something was odd about Pluto. While Planet X was estimated to be about six times more massive than Earth, Pluto’s mass is only 20% that of the Moon, itself 1% of the Earth’s mass.

The year was 2015. After traveling billions and billions of miles through the Erebus, New Horizons encounters the boatman, and the somber lord of the departed. The spacecraft could have been ...