Special guests livened up Friday’s writers panel for CBSEmmy-nominated comedy The Big Bang Theory, which opened with a taped message from Season 6’s guest star Stephen Hawking. “I’m sorry I can’t be there — I got a flat tire,” he joked. “When I’m not playing Words With Friends with Sheldon, I’m thinking about the universe.” Shortly into the panel led by surprise moderator Melissa Rauch, who plays Bernadette on the show, cast member Johnny Galecki stepped up to the fan microphone in full Star Wars Boushh cosplay before joining the panelists onstage. The hourlong chat with showrunner Bill Prady and exec producer/showrunner Steve Molaro, co-executive producers Dave Goetsch, Steve Holland, Eric Kaplan and Jim Reynolds, supervising producer Maria Ferrari, and science consultant Dr. David Saltzberg, mostly kept to fan inquiries and personal geek anecdotes revealing the nerdy leanings of Big Bang Theory‘s creators.A frequent subject of discussion was the sitcom’s OCD physicist character Sheldon, played by Jim Parsons, who yesterday earned an Emmy nom for the role. “It’s interesting in the writers room because in Sheldon you have a character who comes from a place of ‘no’ — ‘No, I’m not going to change at all,’ ” said Prady. As for next season, the panel teased that Raj will talk to girls, Bernadette and Amy will take a trip without Penny, and fans will see Leonard on Hawking’s ship. While you wait, have a look at Hawking’s message: