The boundary between stars and planets appears increasingly indistinct. Objects such as brown dwarfs, neither fully stars nor ...

Astronomers have discovered a flattened structure of matter around the Milky Way that explains the unusual motion of nearby galaxies.

Mercury, Venus, and Mars sit within the same general neighborhood as Earth, yet each has followed a radically different path.

Previous studies found two of the closest planets outside the Solar System around this star, but missed the really exciting ...

The results, published in February in the journal Monthly Notices of the Royal Astronomical Society, show that under these conditions some exomoons could remain warm enough for liquid water — and ...