Leonard and Penny
After Leonard and Sheldon co-publish a physics paper, they must defend themselves against criticism from an online bully. Also, girls' night finds Penny, Amy and Bernadette confronting embarrassing moments from their past, on THE BIG BANG THEORY, Thursday, Feb. 5 (8:00-8:31, ET/PT), on the CBS Television Network. Pictured left to right: Johnny Galecki and Kaley Cuoco-Sweeting Photo: Michael Yarish/Warner Bros. Entertainment Inc. © 2015 WBEI. All rights reserved.