Professor Avi Loeb is a theoretical physicist whose areas of professional interest include cosmology and astrophysics. His new book, "Extraterrestrial: The First Sign of Intelligent Life Beyond Earth", proposes that 'Oumuamua, the interstellar object that passed through our solar system in 2017, may have been the creation of an alien intelligence. Learn more about your ad choices. Visit podcastchoices.com/adchoices