'The Big Bang Theory' Spoilers, Secrets: Names of Characters Based on Real People

Thirteen secrets about the TV series "The Big Bang Theory" have been revealed. Here they are:

1. Dr. Sheldon Cooper (Jim Parsons) is a big "Star Trek" fan. Parsons, however, has never seen a single episode of "Star Trek" and even "Dr. Who."

2. Mayim Blalik, "the girl who played Blossom," has a PhD in neuroscience, which she earned in 2008. She is the only actor from the show with a terminal degree.

3. Johnny Galecki actually dated Kaley Cuoco (his character Leonard's onscreen girlfriend, Penny) during the first few seasons. He also dated Sara Gilbert during his time on "Roseanne," again, his onscreen love interest.

4. Leonard and Sheldon's apartment 4A actually doesn't exist. The streets and places that point to its location exist though – Pasedena at 2311 Los Robles, across the street from Colorado Avenue Chevron station.

5. In 2010, a show called "The Theorists" aired in Belarus. But before anything needed to be done to address this obvious copying, the actors all quit when they discovered the show was a stolen idea from America.

6. Students and staff of the California Institute of Technology, or CalTech, attend the filming of most of the episodes.

7. Names of the characters are based on real people. Howard Wolowitz was someone the creator worked on computers with. Sheldon and Leonard are named from legendary TV producer Sheldon Leonard. Leonard's last name came from two well-known scientists, Douglas and Robert Hofstader.

8. The coffee table in Leonard and Sheldon's apartment are covered with authentic items – Mental Floss magazines and the like, and snacks like Red Vine locorice – showing that the set designers pay very close attention to the details.

9. Initially, there was no Penny. A character "Katie" was introduced, played by Amanda Walsh, and she played the character as a toughie. But because of negative audience reactions, she was changed and Cuoco was recast in the role of Penny.

10. The leading ladies suffered major injuries while filming, but the producers hid them well. Cuoco broke her leg while horseback-riding in Season 4. She missed some episodes and when she was back, she was usually behind the counter. Blalik was in a car accident in Season 6 and had to hide an injured right hand during filming.

11. In 2014, "The Big Bang Theory" was extended for another three years, extending the series to at least 10 seasons.

12. In 2013, Brazilian scientists named a newly discovered species of orchid bee "Euglossa bazinga" after Shedon's favorite catchphrase.

13. The Theremin is one of the most difficult instruments to play. When Sheldon plays it on the show, Parsons actually does the playing.