The official number of exoplanets—planets outside our solar system—tracked by NASA has reached 6,000. Confirmed planets are ...

The solar system lost its ninth planet back when Pluto was demoted to a dwarf planet, but research might indicate that there ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Our solar system ...

The coldest planet in the Solar System is Uranus, which is surprisingly colder than Neptune due to its unique internal heat ...

Astronomers have picked up evidence of an Earth-sized world, distinct from the previously hypothesised Planet Nine and Planet ...

Who hasn't looked into the sky and wondered if there's life out there, somewhere, looking back at us? Is it possible there's ...

A research team led by geophysicists at UC San Diego’s Scripps Institution of Oceanography provides an explanation for ...

Astronomers have been scouring the outer solar system for signs of a hypothetical ninth planet for almost a decade, without success. However, we may finally be on the cusp of finding it, experts say.

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labelled as Planet X, prominent astronomers ...

Earth will move between Saturn and the sun this weekend, offering prime views of Saturn in what's known as "opposition." Here's what to know.