'The Big Bang Theory' sneak peek: Sheldon's hairy situation

Despite all his scientific exploits, there's one thing that Sheldon (Jim Parsons) hasn't figured out how to do yet...make his hair stop growing. This becomes a problem on Thursday's (Feb. 23) episode of "The Big Bang Theory."

In some sneak preview photos, we get a look at what it's like when thing go haywire for Sheldon after his barber gets sick. Being the creature of habit that he is, the brilliant physicist is unable to cope. How else could you explain him playing bongos?

In another storyline, Howard (Simon Helberg) tells Bernadette (Melissa Rauch) that he is starting to have second thoughts about his planned trip into space. This is probably a good thing because it's unlikely that he'll be able to survive more than 10 minutes up there without having an anxiety attack. And lest we forget, he's also supposed to be getting married.

Here are some more photos...