Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't been for lack of trying. According to a new paper by Thomas Winterhalder of ...

The search for an unknown planet in our solar system has inspired astronomers for more than a century. Now, a recent study suggests a potential new candidate, which the paper’s authors have dubbed ...

A tiny meteorite is rewriting what scientists thought they knew about the origins of our solar system. New evidence found in shavings from a meteorite known as Northwest Africa 12264 — a 50-gram (1.8 ...

A planet-size object that possibly once visited the solar system may have permanently changed our cosmic neighborhood by warping the orbits of the four outer planets, a new study suggests. The ...

Our solar system is a smashing success. A new study suggests that from its earliest period — even before the last of its nebular gas had been consumed — Earth’s solar system and its planets looked ...