Intelligent Life Beyond Earth

Christopher D. Impey, University Distinguished Professor, Astronomy
One question rises above all others when it comes to our place in a vast and ancient Universe, 'Are we alone?' With a billion habitable locations in the Milky Way galaxy, and more than ten billion years for biological experiments to play out, a search for intelligent life beyond Earth is well-motivated. Unfortunately, the single example of life on Earth gives no clear indication of whether intelligence is an inevitable or an extremely rare consequence of biological evolution. The search for extraterrestrial intelligence, or SETI, is more appropriately called the search for extraterrestrial technology. So far, the search for intelligent aliens by their electromagnetic communication has met with half a century of stony silence. It's challenging to define life, and even more difficult to make general definitions of intelligence and technology. We'll look at the premises and assumptions involved in the search, the strategies used, and the profound consequences of making contact.