The endlessly fascinating question of whether we are alone in the universe has always been accompanied by another, more complicated one: if there is extraterrestrial life, how would we communicate with it? In his book Extraterrestrial Languages, Daniel Oberhaus leads readers on a quest for extraterrestrial communication. Exploring Earthlings’ various attempts to reach out to non-Earthlings over the centuries, he poses some not entirely answerable questions. If we send a message into space, will extraterrestrial beings receive it? Will they understand? What languages will they (and we) speak? If we can’t even communicate with dolphins and whales, which are mammals, or chimpanzees and gorillas, which are primates, how are we going to communicate with sentient beings that evolved on another planet? If we want to send a message to far-future humans to, say, warn them not to open a container of radioactive waste from a nuclear plant, what would we put on the container to communicate the danger within? Is there not only a universal grammar (as Noam Chomsky has posited), but also a grammar of the universe? In this incredibly fascinating conversation Shermer and Oberhaus also discuss: • the late-19 th • -century idea to communicate with Martians via Morse code and mirrors • the emergence in the 20 th • century of SETI (the search for extraterrestrial intelligence), CETI (communication with extraterrestrial intelligence), and finally METI (messaging extraterrestrial intelligence) • the one-way space voyage of Ella, an artificial intelligence agent that can play cards, tell fortunes, and recite poetry • different media used in attempts at extraterrestrial communication, from microwave systems to plaques on spacecrafts to formal logic, and our attempts to formulate a language for our message, including the Astraglossa and two generations of Lincos (lingua cosmica) • how philosophy, linguistics, mathematics, science, and art have informed the design or limited the effectiveness of our interstellar messaging. Daniel Oberhaus is a science and technology journalist whose work has appeared in Wired, the Atlantic, Popular Mechanics, Slate, the Baffler, Nautilus, Vice, the Awl, and other publications. Listen to Science Salon via Apple Podcasts, Spotify, Google Play Music, Stitcher, iHeartRadio, TuneIn, and Soundcloud. You play a vital part in our commitment to promote science and reason. If you enjoy the Science Salon Podcast, please show your support by making a donation, or by becoming a patron.