Astronomers have uncovered a massive new trans-Neptunian object, 2017 OF201, lurking at the edge of our solar system. With an ...

From the scorching surface of Mercury to the icy edges of Neptune, our planetary neighborhood is full of wonders. The order of the planets isn’t just trivia—it tells a story about temperature, ...

These planets have circular orbits similar to the orbits of planets in our solar system. At least two of the recently detected planets have approximately circular orbits.

NASA's Voyager 1 launched 48 years ago in September 1977 on a decades-spanning journey to study the cosmos and search for ...

New discoveries of objects in the Kuiper Belt have also presented challenges for the Planet Nine theory. The latest is known ...

PLANET MAKER. In this artwork showing the early solar system, an enormous dust disk stretches around the Sun and serves as a breeding ground for new planets as material clumps together.

Such synchrony may occur when planets first form, but astronomers theorize that as time goes on, its likely for orbits to get knocked out of rhythm.

Carbon dioxide has been detected on a planet outside our solar system for the first time. The gas has been observed directly by the James Webb Space Telescope on four exoplanets, all belonging to ...

A smaller planet more like Earth or Mars could have been pushed to the outer reaches of our solar system (or into deep space), according to a new paper. Scientists think Planet 9 used to be more ...