When you buy through links on our articles, Future and its syndication partners may earn a commission. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute ...

Once the quirky underdog of our solar system, Pluto held planetary status until 2006, when it got a cosmic demotion that still stings space fans. Discovered in 1930, Pluto was the ninth planet for ...

Before Pluto was discovered, it was predicted. Astronomers had observed that massive objects can affect the orbits of their neighbors and, after seeing deviations in the orbits of Uranus and Neptune, ...

Pluto, with a mass that is 0.2 percent of Earth’s, should have lost its radioactive heat by now, said Bray. Will Grundy of Lowell Observatory said Pluto has enough rock to retain radioactivity from ...

When I was growing up, the list of planets in our solar system included a small planet far from the Sun called Pluto. Then, a number of objects about the same size as Pluto began to be discovered.

After passing in the state senate, a new bill that would officially designate Pluto as Arizona's state planet is now at the will of Gov. Katie Hobbs. Since its discovery in Flagstaff, Pluto has become ...

Pluto may be small, but it has one of the most unusual moons in the solar system. Charon is so big compared to Pluto that the ...

NASA explains Pluto's newly discovered "blue sky" and whether or not potential astronauts could ever witness an Earth-like sunrise. The New Horizons space probe sent back its first color images of ...