Two characters named after one man
The two physicists at the centre of The Big Bang Theory, SHELDON COOPER and LEONARD HOFSTADTER, are both named after the same person: Sheldon Leonard, a Hollywood producer and actor who made classic American sitcoms in the 1950s and 1960s. Leonard's surname, Hofstadter, is a nod to two real scientists, a Nobel prize-winning physicist and his son, a well-known writer about thinking and computers.
The show ran from 2007 to 2019, twelve series and 279 episodes, and when it ended it was the longest-running multi-camera sitcom in American history, filmed in front of a studio audience like the classics on our sitcoms page. Its theme song, which rattles through the history of the universe in under half a minute, was written by the Canadian band Barenaked Ladies.
Real science on the whiteboards
The equations on the whiteboards in Sheldon and Leonard's APARTMENT are real. A physicist at the University of California, Los Angeles, David Saltzberg, checked every script and filled the boards with genuine working, sometimes slipping in in-jokes for scientists watching. Fans with physics degrees would pause episodes to read them. The characters work at CALTECH, the California Institute of Technology, a real university in Pasadena.
Several real scientists appeared as themselves. Stephen Hawking guest-starred seven times, often teasing Sheldon, and our scientists page covers some of his fellow physicists. The actor who played AMY, a neuroscientist, Mayim Bialik, has a real doctorate in neuroscience.
Bazinga and a lullaby
Sheldon's catchphrase, BAZINGA, which he says after a joke or prank, first appeared in the second series and became so popular that it was printed on T-shirts, mugs and even adopted as a name for a newly discovered species of bee. His other famous habit is knocking three times and saying the name of the person inside, three times over, before entering a room. In one episode he explains that his favourite number is 73, because it is the twenty-first prime number, and its mirror image, 37, is the twelfth, and mathematicians later proved that 73 is the only number with that exact set of properties.
When he is ill, Sheldon insists on being sung SOFT KITTY, a lullaby his mother sang to him. The song was based on a real children's song from the 1930s, and in 2015 the family of the woman who wrote it went to court over its use. SPOCK, the logical science officer from Star Trek, is Sheldon's hero.
The rest of the gang
PENNY, the aspiring actor who lives across the hall, never has her maiden name revealed in all twelve series. HOWARD WOLOWITZ, an engineer, actually goes into space in one series, and RAJ, from India, spends the first few series too shy to speak to women at all. BERNADETTE, a microbiologist, marries Howard, and STUART runs the COMIC book shop. A prequel, Young Sheldon, showing Sheldon's childhood in Texas, ran from 2017 to 2024. In the final series, Sheldon and Amy win the Nobel Prize in physics for their made-up theory, super-asymmetry, and Jim Parsons, who played Sheldon, won four Emmy awards for the part. Some teachers in Britain even credited the show with helping to make physics more popular with students. The grid also holds PHYSICS, ROOMMATE, GEEK, NERD and SARCASM, which Sheldon famously cannot detect.