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

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

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

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

Astronomers from MIT have uncovered a dramatic celestial spectacle: a Mercury-sized exoplanet that is rapidly disintegrating ...

Saturn orbits the Sun at roughly 9.69 km/s, maintaining its grand system of rings as it cruises through space. Uranus moves at about 6.81 km/s, spinning on its unique sideways axis as it orbits ...

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

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

Astronomers discovered a planet that orbits its star so closely that its surface is being scorched into magma and vaporizing ...

It orbits not two stars but two brown dwarfs ... A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). Jupiter is our solar system’s largest planet. The two brown ...

Astronomers Spot First-of-Its-Kind Planet Disintegrating and Shedding Debris From a ‘Comet-Like’ Tail Planets have been one ...