The possibility of alien life has captivated the human imagination for decades and has been at the center of some of our most popular fictional stories. But one scientist has made a controversial claim that aliens are no long a fiction but a reality.

Avi Loeb is a theoretical physicist and former chair of the astronomy department at Harvard University. For the past few years, he’s argued that an alien artifact, called Oumuamua, passed by Earth in 2017.

As you can imagine, a Harvard professor going on record that aliens exist caused quite a stir in the scientific community. On this episode, we talk through this controversy with Loeb and why he thinks we need to invest more in the search for alien life by developing a new field of “space archaeology.”