I/ATLAS might be over 7 billion years old, a new study reports, which would make it the oldest comet known. But experts caution we need more data.

A mystery interstellar object discovered last week is likely to be the oldest comet ever seen—possibly predating our solar ...

The Milky Way could have many more satellite galaxies than scientists have previously been able to predict or observe, ...

A renowned physicist believes he's cracked the mystery of where a giant unidentified object hurtling through our solar system ...