I know many people like both these guys. Neil Tyson (famous astrophysicist) has been many times on the daily show interviewed by Jon Stewart and also in the Colbert Report with Stephen Colbert.
This time it was Neil Tyson who interviewed Jon Stewart. In Tyson's radio show the Startalk Radio. Stewart revealed many things. Says he's also a very scientific person who even took chemistry in college. But abandoned that in favor of psychology because "it was easier and didn't need to find any exact answers. All I needed was to write alot - well I can do that".
Here's the link to the show. It's a podcast of about 40min or so.