Measurements of this interstellar comet’s molecular makeup show an excess of heavy water molecules that is dramatically different from anything known to have ever formed around our sun ...

Swipe Down for Full Video Story We’ve thrown a lot of disasters at Earth over the years: from asteroids and aliens, to the ...

Billions of years ago, while the solar system was still young, a massive object may have drifted into it. It's not a spaceship, but it is an alien visitor in its own right—a colossal interstellar body ...

One million alien visitors from another star system could already be lurking in the solar system. We aren't talking about "little green men" here, however — more "little (and not so little) gray rocks ...

A rare comet from another star system is revealing just how different alien solar systems may be from our own.

Here’s what you’ll learn when you read this story: Every time an interstellar object comes whizzing into our Solar System, it brings with it a certain intrigue. Where is it from? How did it form? Why ...

A mysterious comet from beyond our solar system is giving astronomers a rare glimpse into alien worlds — and it may have ...