New studies find the interstellar comet 2I/Borisov is the most "pristine" ever discovered.
Was ‘Oumuamua a rock or an alien scout? Harvard astronomer talks controversial hypothesis in new book
Ari Loeb, who suggested in 2018 that the mysterious object was an alien craft, is back to discuss the evidence.
For the first time, an object from outside our solar system is observed traveling through our neighborhood.