When it comes to the search for extraterrestrial intelligence (SETI), sometimes light years from Earth, how do you even know where to start? 

Our guest this week is Jason Wright, professor of astronomy and astrophysics at Penn State, and an expert in SETI. If there is intelligent life out there, he and his colleagues are best-placed to be able to find it. 

We asked him about where it all started, and the signals and signatures he looks for in his searches.