I'm Seth Shostak, Senior Astronomer at the SETI Institute AMA.
My day job, believe it or not, is to hunt for aliens -- just like in the movie "Contact". I'm also the host of the "Big Picture Science" radio show, produced right here at the SETI Institute in lovely, glamorous Mountain View, California. I'll be around for at least the next 2 hours to answer questions about astronomy, SETI, or what you should do if gray guys from another stellar system haul you out of your bedroom.
EDIT: Verification https://twitter.com/#!/SethShostak EDIT2: Well, I gotta go feed the pet muskrats. It's been fun, and we'll do it again soon ... if you want!