Almost 10 years ago, a NASA spacecraft was able to take several photos of Pluto, known for decades as a planet before it was ...

A powerful new observatory is the best hope yet for finding the elusive Planet 9, a large planet that some scientists say is ...

A ninth planet, Pluto, had been discovered ... where you can see mountains and craters and valleys, all this stuff up close," ...

The relative quantities of volatile gases like methane and ethane can reveal key details about distant Kuiper Belt objects.

We bring up this history because it is directly related to the story of Pluto. In 1846, Neptune, the fourth of the giant planets beyond the asteroid belt, was discovered—thirty times farther ...

Unlike other planets that have a more or less circular, equatorial orbit around the sun, Pluto’s is sharply inclined and ...

But by counting all the asteroids, the number got up above ... nine planets, which came about in the 1960s and lasted only until 2006, was a blip on the screen. And if you are still a Pluto ...

With the exception of Pluto, planets in ... remotely for terrestrial planets around other stars. The layers of gases surrounding the surface of a planet make up what is known as an atmosphere.