You remember it, even if you've forgotten how to pronounce it. Oumuamua was a cigar-shaped object that passed through our inner solar system and mystified plenty of scientists. It didn't fit any of the categories we have for space debris, comets or meteors. So what was it? Where did it come from? When will we find more?
A new book by a Harvard University astrophysicist makes the case that Oumuamua was proof of intelligent life beyond Earth. And as we build more powerful instruments, he says, it will only be the first of many we'll find.
GUEST: Avi Loeb, Harvard University, author of Extraterrestrial: The First Sign of Intelligent Life Beyond Earth