The appearance of the interstellar objects (ISOs) 'Oumuamua and Comet Borisov in 2017 and 2019, respectively, created a surge of interest. What were they? Where did they come from? Unfortunately, they ...

Interstellar asteroids visiting our solar system from parts unknown used to be the stuff of science fiction. But today, we know of at least two such bodies Oumuamua and 2I/Borisov respectively ...

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 ...