10 "Big Bang Theory'' Facts Most People Don`t Know

The Top Ten
1 Frequently, Leonard has no actual glass in his glasses.
2 Penny is the only one of the show's main characters whose last name is still a mystery.
3 Mayim Bialik is the only cast member with a PhD: In 2008, she received her advanced degree in neuroscience.
4 Penny has been using the same purse on the show since the second episode of the first season.
5 The line in the show's theme, "Autotrophs began to drool," is a purposeful error/joke: Autotrophs are life forms like plants or algae that create their own energy, and therefore don't need to eat.
6 The actors actually learned how to play the instruments their characters play on the show (theremin, cello, harp).
7 Sheldon's "soothing song," "Soft Kitty," is based on an Australian children's song from executive producer Bill Prady's daughter's preschool.

Is it weird that I sing this to my dog and it helps her fall asleep?

8 Melissa Rauch based her character's voice on her mother's, "Only without the Jersey."
9 Jim Parsons has never seen Star Trek or Doctor Who, a fact that would be seriously depressing to Sheldon Cooper.
10 Briefly, a complete rip-off of the show called The Theorists was aired in Belarus. When the actors discovered they were performing in a stolen show, they all quit, which negated the need for legal action from BBT's creators.
The Contenders
11 Salt and pepper are never used correctly
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