In 2017, the Pan-STARRS telescope in Hawaii spotted an interstellar object passing by Earth for the first time. Shortly after, Harvard’s Prof Avi Loeb was met with a backlash from the scientific community for suggesting it could be of alien origin.Now, several years on, he has written a book, Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, outlining why we still can’t out rule the possibility, and why scientists should always keep an open mind.We speak to Avi on this week's episode of the Science Focus Podcast. He tells us why he believes the object, 'Oumuamua, was of alien origin, and what problems this reveals about the way modern physics is conducted.Read an edited excerpt of this interviewLet us know what you think of the episode with a review or a comment wherever you listen to your podcasts.Subscribe to the Science Focus Podcast on these services: Acast, iTunes, Stitcher, RSS, OvercastRead the full transcription of this episode [this will open in a new window]Listen to more episodes of the Science Focus Podcast:Dr Douglas Vakoch: Should we try to contact aliens?Bergur Finnbogason: Project Discovery and its search for exoplanetsDr Erin Macdonald: Is there science in Star Trek?What if the Earth’s magnetic field died? – Jim Al-KhaliliBuilding a base on the Moon, and crafting believable sci-fi – Andy WeirDr Becky Smethurst: How do you actually find a black hole? Hosted on Acast. See acast.com/privacy for more information.