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 ...

Astronomers have discovered two new exoplanets that are similar to other worlds found in the Milky Way, but unlike any in our ...

LONDON — A long-lost planet that helped create the Moon may have formed much closer to the Sun than scientists once thought, according to new research. Scientists have discovered that Theia, the ...

An artist's impression shows the "inside out" planetary system around the star LHS 1903. - ESA An exoplanetary system about 116 light-years from Earth could flip the script on how planets form, ...