If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth.

The presence of another planet in the solar system could explain the odd movements of some of the bodies in the Kuiper Belt.

Astronomers have detected a promising sign of a ninth planet lurking at the the farthest reaches of the Solar System.

The solar system consists of our star, the sun, and everything bound to it by gravity: the planets Mercury, Venus, Earth, ...

Astronomers using the James Webb Space Telescope have directly detected the faint glow of a planet that’s colder than any ...

Earth's forests play a critical role in keeping our planet habitable. Often called the "lungs of the Earth," forests cover ...

Once a year, this planet passes through a celestial beehive typically seen in the night sky during the spring. And it's about ...

A rare and dramatic scene unfolds 140 light-years from Earth. A rocky planet, once whole, is now crumbling to dust under the ...

Scientists have discovered a planet that is literally falling apart as it orbits its star. Located about 140 light-years from ...

Pluto was discovered in 1930 in Arizona, but in 2006 scientists decided to cut Pluto from the planetary line up. Here is why ...

Wildlife filmmaker Bertie Gregory curated the final selection for the "NatGeoYourShotOurHome" challenge from thousands of ...

The planet is "crumbling to pieces," shedding the equivalent of Mount Everest’s mass every 30.5-hour orbit and will be ...