A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in our solar system.

Pluto is a bit of a loner. The dwarf planet is no longer considered a regular planet; it does not orbit on the same plane as the solar system's eight planets; and its orbit is both highly elliptical ...

It's been 20 years since Pluto was declassified as the ninth planet in our solar system, and many people wish it had never lost its status. A recent comment from NASA Administrator Jared Isaacman ...

The head of NASA says maybe Pluto is a planet after all. He is wrong because Pluto is part of the rest of the solar system ...

Pluto was reclassified as a dwarf planet in 2006, but new discoveries and fresh debate are reigniting calls to restore its planet status. Learn why Pluto lost its title, what scientists discovered ...

On August 24, 2006, our solar system lost a planet. It wasn't by cataclysmic destruction, but rather by the vote of the International Astronomical Union, which declared that Pluto, considered the ...

Current NASA head Jared Isaacman, himself something of a controversial choice, is determined to get Pluto reclassified as a planet again. Here's why.

In the far reaches of our solar system — beyond the outermost planet Neptune — resides a host of icy and desolate celestial ...

The celestial body’s status as the solar system's ninth planet was withdrawn in 2006. Now some experts say we might want to reconsider ...