'The Big Bang Theory' preview: Will the Raj and Penny experiment have a positive outcome?

big-bang-theory-season-4-cbs.jpgAs far as comedy cliffhangers go, " The Big Bang Theory" gave us an Avogadro's number at the end of last season.

When last we joined our group of geeks, Raj and Penny engaged in a covalent bond, Leonard and Priya's relationship seemed to be undergoing exponential decay and Howard and Bernadette's partnership appears to be headed for a tensile strength test. And then there's whatever Sheldon does, which is typically talk about things we're not smart enough to understand.

Here's some of what we have to look forward to during Thursday's (Sept. 22) premiere and for the rest of Season 5...

Raj and Penny -- This probably should be items #1 and #2 given how unlikely this pairing is. Raj ( Kunal Nayyar) can't talk to women unless he's been drinking and Penny ( Kaley Cuoco), well, she's never really expressed an interest in Raj. So the fact that last season concluded with a 'big bang' between the two was a surprised to everyone. Will this relationship continue? Will Raj now be able to talk to other women when he's not under the influence? Is Penny as horrified as she looks?

Leonard and Priya -- Will she or won't she? Priya ( Aarti Mann) is considering breaking up with Leonard ( Johnny Galecki) and moving back to India because her parents don't want them to date. And does Leonard still have feelings for his one-time love, Penny?

Howard and Bernadette -- Howard's ( Simon Helberg) self-loathing goes to a new low after his fiancee Bernadette ( Melissa Rauch) announces she's not only earned her Ph.D., but she's secured a high-paying job. With her new-found financial status, she buys Howard a Rolex. While most would be grateful for such a present, Howard is the center of his own universe. He feels emasculated and resentful on so many levels. Will the wedding go forward, or will Howard find a way to screw it up?

Sheldon and Amy -- Will their relationship ever extend beyond the computer screen and into the bedroom? Will they ever display a human emotion? Do they only think in 1s and 0s?

The atomic clock is ticking to the premiere at 8 p.m. ET.
Photo/Video credit: CBS