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 ...

Simulations reveal that Jupiter’s rapid growth disrupted the early solar system, creating rings where new planetesimals formed much later than expected. These late-forming bodies match the ages and ...

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 ...