The cast members learned to play their instruments for the show. (Amy plays the harp, Sheldon plays the theremin and recorder, and Leonard plays the cello). In addition, Howard is a professional piano player.
Jim Parsons' audition for the role of Dr. Sheldon Cooper was so good, that Creator Chuck Lorre immediately asked him to come in for a second one, because Lorre wanted to be one hundred percent sure Parsons was as brilliant as he seemed. After the second audition went perfectly, Lorre cast him on the spot.
During the third season, the producers became aware of a series called "The Theorists," produced and broadcast in the country of Belarus, that was a virtual copy of this show. Legal action over copyright infringement would have been futile, since the production company was pretty much owned by the Belarus government. However, a lawsuit turned out not to be necessary, because when word got out that the show was a rip-off, the actors and actresses quit, and the show was immediately cancelled.
On January 14, 2011, CBS gave the series a rare vote of confidence when it issued a three-year renewal through the 2013-14 season. It then received another three-season renewal on March 12, 2014, meaning the show will run at least twelve seasons. This marked the first time in modern television history a scripted television series received back-to-back three-season renewals.
During a first season episode Raj, Leonard, and Howard are trying to find a fourth person to replace Sheldon on their physics bowl team. Raj suggests Mayim Bialik, saying, "You know who's apparently very smart, is the girl who played TV's Blossom (1990). She got a PhD. in neuroscience or something." Leonard responds, "Raj, we're not getting TV's Blossom to join our physics bowl team." During season three, Bialik started playing the regular role of Dr. Amy Farrah-Fowler on the show. Dr. Fowler has a PhD. like Dr. Bialik, in Neurobiology, a.k.a. Neuroscience.
Kaley Cuoco missed filming two episodes of season three, because of a broken leg, that was the result of a horseback riding accident. In her first appearance following the accident, she was filmed standing behind a counter.
Sheldon's soothing song, "Soft Kitty", is based on an Australian children's song from Executive Producer Bill Prady's daughter's pre school. The song has been featured on Australian children's television show Play School (1966).
On January 3, 2013, a team of Brazilian biologists announced their name for a newly-discovered species of orchid bee: Euglossa bazinga. This was to honor the show, and specifically Sheldon's mocking catchphrase "bazinga". Long mistaken for another bee, Euglossa ignita, the new species was deliberately tagged "bazinga" for its history of fooling entomologists. Executive Producer Steven Molaro responded in a press release: "We are always extremely flattered when the science community embraces our show. Sheldon would be honored to know that Euglossa bazinga was inspired by him. In fact, after Mothra (1961) and griffins, bees are his third-favorite flying creature."
Despite the fact that some viewers take Sheldon's behavior, mannerisms, and social skills as a sign that he has Asperger's syndrome, or otherwise falls on the autism spectrum, the producers have persistently denied in many interviews that Sheldon has Asperger's or any other type of autism. It should be noted, however, that Jim Parsons (Sheldon) has stated that he does think that Sheldon actually does have Asperger's syndrome, and portrays him as such.
Sheldon can be seen wearing various versions of "Flash" t-shirts throughout the series. In the series The Flash (2014), character Cisco Ramon frequently wears "The Big Bang Theory"-based shirts, such as one with Sheldon's catchphrase "Bazinga!"
Sheldon frequently wears t-shirts with the characters or symbols of the Green Lantern, the Flash, or the old television show The Greatest American Hero (1981). The shirts from the "Green Lantern" comic book series are various colors with a corresponding symbol, with each color representing a different corps of heroes or villains (Red Lanterns, Orange Lanterns, et cetera). In the comics, each color also represents an emotion, thus possibly giving the viewer a clue to Sheldon's temperament for the day.
Each of the male characters has a signature clothing article that is worn in virtually every episode: Sheldon, t-shirts worn over long-sleeve shirts; Leonard, hoodies worn over a t-shirt and under a jacket; Raj, sweater-vest worn over a shirt, and usually under some type of outerwear; Howard, dickie worn under some type of outerwear. Howard usually has a pin on the left side of his dickie of the head of a space alien, and he wears large belt buckles.
On five episodes or more of season six, Mayim Bialik's right hand was hidden in certain ways and camera shots to conceal the the injury she received, and the glove she wore to cover it, from an automobile accident in August of 2012.
Floors two, three and four of Sheldon and Leonard's apartment building are the same set just re-dressed for each scene. This can be seen in the fact that the scuff marks on the molding are identical on each level as they walk up the stairs.
The full names and occupations of the characters are as follows: Dr. Leonard Leakey Hofstader, Ph.D., Experimental Physicist; Dr. Sheldon Lee Cooper, B.S., M.S., M.A., Ph.D., Sc.D., Theoretical Physicist; Howard Joel Wolowitz, M.Eng, Aerospace Engineer; Dr. Rajesh Ramayan Koothrappali, Ph.D., Astrophysics; Dr. Bernadette Mary Ann Rostenkowski Wolowitz, Ph.D., Microbiology; and Dr. Amy Farrah Fowler, Ph.D., Neurobiology. Penny's last name has yet to be revealed.
Bernadette did not originally have such a high pitched voice. When she first appeared, she had a rather normal pitch voice and as her character began to take shape, she adopted the quirky high pitched voice which Melissa Rauch says she based off her mother's voice "without the Jersey".
The theme song uses the line "Autotrophs began to drool." This is a science joke. The word "autotroph" means "self-nourishing" and refers to life-forms (plants and algae) that create their own food internally and don't need to eat.
The opening cast shot always features the series' regulars enjoying dinner together. The opening cast credits cast shot in seasons two through four, for instance, depict Howard, Raj, Leonard, Penny, and Sheldon on what appears to be pizza night. However, Leonard is seen holding a plate with a white meat, and some type of vegetable, such as asparagus spears. This is apparently a reference to his lactose intolerance, which would make him averse to pizza (unless he ordered it without cheese). Amy and Bernadette were added to the shot starting in season six, even though both had been regulars on the show since season four.
Penny was an add-on from a different sitcom concept. She had been originally envisioned as Katie, a more cynical, hard-drinking, streetwise girl who worked at a make-up salon. In the original unaired pilot, she was played by Amanda Walsh.
During his appearance on Inside the Actors Studio (1994), Jim Parsons revealed his three favorite scenes: Sheldon receiving a gift from Penny - a napkin signed and used by Leonard Nimoy, Sheldon presenting Amy the relationship agreement, and Sheldon drinking Long Island Iced Tea for the first time.
In the early episodes of season one, Sheldon has two character traits that were not established right away. First, he understood the nature of romantic and sexual relationships. In the first few episodes, he chides Leonard for his hopes of getting into a relationship with Penny, often telling Leonard that he has no chance of having sex with her. Also, Sheldon understood the nature of sarcasm, as he occasionally used it himself in the early episodes. Later, his character evolved into a purely intellectual person and an emotional "man-child", who does not fully understand sex, love, or sarcasm. Second, in the early episodes, Sheldon did not use his three-times knock (knock-knock-knock "Penny", et cetera) that has become one of the character's now well known idiosyncrasies that did not begin until midway through season one.
All of the figurines and posters in Howard's room (and later on in his house with Bernadette) are female superheroes or science fiction characters. The one non-female figurine, Jabba the Hutt, has Princess Leia (in her slave girl costume) sitting in front. Later on in the series, they accumulate a figurine of Bernadette after the episode where he and Raj got a 3-D printer.
Jim Parsons (Sheldon) and Kaley Cuocuo (Penny) are the world's highest paid television actor and actress, with earnings of twenty-nine million dollars and twenty-eight and a half million dollars, having made that income from June 1, 2014 to June 1, 2015. (Forbes 2015)
According to numerous entertainment reports, CBS has reported a large jump in the series' ratings for season six, and has attributed the increased audience to the exposure of the show in re-runs on TBS, which airs the series three nights a week in prime-time blocks of up to three hours.
Leonard's last name, Hofstadter, refers to two well-known scientists: Robert Hofstadter, the 1961 Nobel Laureate in Physics, and his son Douglas R. Hofstadter, who researched consciousness and cognition, and whose best-selling book about philosophy, mathematics, puzzles, art, and music, "Gödel, Escher, Bach: An Eternal Golden Braid", was published in 1979, and won him the 1980 Pulitzer Prize for general non-fiction.
While a guest on the National Public Radio program "Talk of the Nation", Mayim Bialik confirmed that the university, at which the characters attend and/or teach, is based on the California Institute of Technology (Caltech) in Pasadena. Additionally, in one episode, the character of Leonard stated that he worked at Caltech.
Raj says that Spock had a date every seven years. He is referring to Pon Farr, the Vulcan mating cycle that occurs every seven years. Vulcans must mate in the time of Pon Farr, otherwise they will die, so Spock has a mandatory hook-up every seven years.
As avid comic book fans, the guys frequently talk about comic book characters, or are wearing t-shirts or other paraphernalia of comics. They frequently mention DC Comics characters such as Superman, Batman, Green Lantern, the Flash, and Wonder Woman. DC Comics and this show are owned and produced by subsidiaries of Time Warner, Inc.
In tribute to Carol Ann Susi, who played Howard's mom, who recently passed, a small picture of her is on the side of Sheldon and Leonard's fridge. It is a small square that can be seen in episodes after her death. The picture is so small that it cannot be recognized. However, in the behind the scenes DVD feature, it is mentioned that it is her.
While much of the show has focused on String Theory, the most often mentioned physicist is Hawking. However, the "Father of String Theory" is Dr. Leonard Susskind, who has proven Hawking wrong on several occasions.
Sheldon has invented a time of day called "pre-evening". In Turkish, there's a time of day called "aksamustu", which basically means "pre-evening". In Bengali, there is a time called "godhuli", which also means "pre-evening". In Czech, there is a time of day called "podvecer", which also means "pre-evening".
Sheldon verbally reveals his and Leonard's Pasadena apartment 4A's location as being 2311 Los Robles in season four, episode five, "The Desperation Emanation". In the one hundredth episode, Sheldon also reveals that their apartment building is across the street from the Colorado Avenue Chevron gas station, making their building a corner location, on the corner of Los Robles and Colorado. There are two incidences of this intersection in southern California, both located in Los Angeles County, the first one is E. Colorado Boulevard and N. Los Robles Avenue, Pasadena, California, 91101, and the second one is Colorado Boulevard and Los Robles Street, Los Angeles, California, 90041. However, 2311 Los Robles is not an address by either one of those intersections. Leonard does reveal, however, that they live in Pasadena, while declaring himself the Darth Vader of Pasadena.
Howard's mother was almost never seen, only heard, despite often being as close as the next room. Conversely, via Skype, Raj's parents are quite often seen, despite being across the world in India, except when his father visited Pasadena.
In one of the episodes, Raj and Leonard run into Nathan Fillion. They greet him and tell him they are big fans of Firefly (2001) and Dr. Horrible's Sing-Along Blog (2008). Simon Helberg (Howard) played the character "Moist" in Dr. Horrible's.
In early episodes of season one, Sheldon mentions having an older brother, in addition to his twin sister, Missy. In one instance, he mentions being bullied by this older brother. However, while Missy has been seen on the show, the brother was never mentioned again, even when his mother visits. She only mentions Missy. He was mentioned in season three episode four, as well. In later seasons, Sheldon's brother was mentioned in season seven episode eleven, season eight episode twenty, season eight episode twenty-three, and season nine episode five.
The names Sheldon, Leonard, Cooper, and Hofstadter all appear on the list of Nobel Laureates in Physics. Furthermore, Sheldon and Cooper are names of physicists who won the prize for theory, and Leonard and Hofstadter are names of those who won for experiment.
Leonard's middle name is Leakey. Leakey is the name of a renowned family in the fields of archaeology, anthropology, and paleontology. Louis Leakey (1903-72) was a British archaeologist and naturalist, whose critical work helped to establish human evolutionary development in Africa. He also created or co-created several organizations for future research and for protecting wildlife in Africa. He also helped to establish a tradition of palaeoanthropological inquiry, and was able to motivate the next generation to continue, especially within his own family. Mary Leakey (1913-96), his wife, was a British archaeologist and anthropologist who discovered many firsts. For much of her career, she worked together with her husband in Kenya's Olduvai Gorge, uncovering relics of ancient hominines. She also developed a system of classifying the relics they found. After Louis' death, she became a leading palaeoanthropologist, helping to further establish the Leakey name and tradition with the training of her son, Richard Leakey.
In every one of the main female characters' first appearances on the show, the first person to speak to them are their future mates. In the pilot, when Penny is introduced, the first person to speak to her is Leonard, in season three, episode five, "The Creepy Candy Coating Corollary", when Bernadette is introduced, the first person to speak to her is Howard, and in season three, episode twenty-three, "The Lunar Excitation", when Amy is introduced, the first person to speak to her is Sheldon.
In the same scene that Raj says that "Blossom" would be a great addition to the Physics Bowl team, he also mentions that the "girl from The Wonder Years" was also smart. In a later episode, Danica McKeller (who played Winnie on The Wonder Years (1988)) plays a character who makes out with Raj.
While having lunch at the University canteen, or other eating scenes, characters don't actually eat most of the time. Howard only pretends to eat the food by moving his mouth like he is chewing it, Sheldon and Leonard just play with their food with fork. Amy and Penny are sometimes shown eating food. They only talk most of the time.
Leonard is the only male lead character who hasn't taken his pants off while under the influence: Raj took his off at the coffee shop while under the influence of an experimental personality altering drug, Howard took his off on the international space station after his teammates gave him a shot for his anxiety, and Sheldon took his off on stage while accepting an award in science after Penny gives him multiple glasses of wine.
From June 2015 to June 2016, cast members Jim Parsons, Johnny Galecki, Simon Helberg, and Kunal Nayyar were the top four highest paid television actors, and actress Kaley Cuoco was the highest paid actress for the same time period.
When Chuck Lorre first pitched the show to the studios, he intended for it be an adult version of the show as seen today. In the hopes of attracting as many male viewers as possible, he wrote the show with an all female cast. The female characters associated with the male main characters reflect the original characters' personas: Sheldon was originally Missy (a tall, attractive brunette from Texas, who lacked intelligence), and lived with an older woman named Beverly (an intelligent scientist from New Jersey, who took advantage of her roommate. Penny lived, as she does now, across the hall, but originally had an Indian roommate named Priya (a lawyer from New Delhi). It could be assumed that characters like Bernadette and Amy might have been potential characters to add later, as well as a single male love interest in the form of unintelligent Zack.
In season five, episode nineteen, "The Weekend Vortex", for some reason, Kaley Cuoco is omitted from the credits, dispite appearing in the episode. In the beginning of the episode, while Leonard, Howard, and Raj are walking up the stairs, the credits start with "Starring Johnny Galecki, Jim Parsons, Simon Helberg, Kunal Nayyar..." instead of "Starring Johnny Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, Kunal Nayyar..."
While Wil Wheaton was appearing on the show, he took a photo of the set's coffee table and posted it on his much-followed blog. Among the materials on the coffee table, were copies of "Mental Floss Magazine"; "The Sandman Vol. 6: Fables and Reflections" by Neil Gaiman; a package of Pepperidge Farm Sausalito milk chocolate macadamia nut chunk cookies; a package of Red Vines; and a package of Tim's brand original-flavor lightly salted potato chips.
In one Halloween episode, Amy and Sheldon are brainstorming couples-themed costumes, in which to dress up. Sheldon has a list of their suggestions written on a whiteboard, and while his half of the board has various genre characters listed, Amy's half has mostly romantic couples. The only exception is a listing that reads "Blossom and Joey", a reference to the title character Mayim Bialik portrayed in Blossom (1990), and that character's brother.
In season one, episode seven, "The Dumpling Paradox", when Leonard talks about cutting Raj in half to play Halo, Raj speaks with Penny in the room. If you look at the table, you will notice that Raj does not have an alcoholic drink.
In season six, episode ten, "The Fish Guts Replacement", Sheldon reveals that his favorite cartoon theme song is Teenage Mutant Ninja Turtles..."turtle power!" The infectious 90's anthem was written by none other than Big Bang Theory show runner and writer Chuck Lorre.
Sheldon and Leonard are atheists, yet the scientific theory that is the basis for their careers (and the show's title) "The Big Bang Theory" was actually proposed and developed by a Catholic priest, Father Georges Lemaître.
Simon Helberg's father guest starred on M*A*S*H (1972), in season eleven, episode eight, "The Moon is Not Blue". He played Corporal Bannister, who is plagued with panic attacks whenever he is around women. Hawkeye and B.J. give him pills for confidence without telling him they are placebos. The pills work, and he becomes a ladies' man. This is the same as Raj, but he remedies it with alcohol.
In season four, Penny is going out with Zack, and they attend a costume party at the comic book store, where he goes as Superman, and she goes as Wonder Woman. Kaley Cuoco briefly dated Henry Cavill, who portrays Superman in Man of Steel (2013), Batman v Superman: Dawn of Justice (2016), and the upcoming Justice League movies.
Penny (Kaley Cuoco) has never had her maiden name disclosed on-screen before. An interview with one of the writer's of the show revealed that the writer's of the show are aware of this, and due to superstitious reasons, are intent on not revealing it ever on-camera.
Simon Helberg (Howard) used to play Seth, a geek from Caltech, on Joey (2004). He also dated a woman named Molly, who had a squeaky voice. Howard works for Caltech, and is married to Bernadette, who also has a squeaky voice.
Howard is the first of the gang to get married and have a child. In real-life, Simon Helberg was the first main cast member to get married in summer 2007, just before the start of the series, and have children in 2012 and 2014.
As a child, Kunal Nayyar (Raj) had a crush on Danica McKellar (Gwendolyn "Winnie" Cooper) from The Wonder Years (1988), and on this show, he actually had a relationship with her, which surprisingly made him lose all interest in her.
Casey Sanders (Bernedette's dad) plays a cop. He also appeared in season three, episode twelve of Sons of Anarchy (2008) as a lead Sheriff, a show also based in California, but different areas. This show being in Pasadena, and Sons of Anarchy (2008) being in a town called "Charming".
In season three, episode five, "The Creepy Candy Coating Corollary", Howard is introduced to Bernadette. As they get to know each other, he reveals that he lost his virginity in a car. Bernadette replies that she did as well. In this episode, Howard tells Raj and Leonard that he lost his virginity to his cousin, and describes being at the back of the house during a family gathering. Meaning that he lied to somebody.
In the unaired pilot episode, Sheldon is portrayed as having a lot of qualities he didn't have in the finished script. He was able to understand sarcasm, and wasn't as condescending as normal. He also was revealed to have engaged in sexual relations.
Currently (November 2016), the show broadcasts over five channels in South Africa (The most of any show at any given time), the latest episodes on M-Net, and reruns on VUZU, VUZU AMP, M-Net Family, Comedy Central, and SABC3.
Leonard (Johnny Galecki) and Amy (Mayim Bialik) appeared in Blossom (1990); a show in which Bialik portrayed the title character. During this show's first season, Raj suggests the gang recruit Mayim Bialik for their Physics Bowl team when Sheldon pulls out, saying, "You know who's apparently very smart, is the girl who played TV's Blossom. She got a PhD in Neuroscience or something." Bialik soon joined the cast during the third season as Dr. Amy Farrah-Fowler, who has a PhD in Neurobiology, a.k.a. Neuroscience.
Much like the four main male characters, Amy and Bernadette wear the same style of clothing in every episode. Amy wears a knee length skirt with dark or colorful tights, a long sleeve, collared blouse with a knitted sleeveless cardigan, often underneath a long sleeved cardigan. Bernadette wears a mid-thigh length, usually floral, dress with dark or colored tights, and a short sleeved button up cardigan. Penny is the only main character whose clothes do not follow a pattern.
In season three, episode sixteen, "The Excelsior Acquisition", Stan Lee is set to be at Stuart's comic book store for an autograph signing, around the same time Sheldon and Penny are in traffic court. As Sheldon stands next to the judge at his stand, the name reads J. Kirby, a reference to Stan Lee's partner and co-creator of various Marvel characters, Jack Kirby.
The UK's Channel Four and E4 appear to have slightly edited dialogue from certain episodes as the audience laughter abruptly starts, stops, or jumps, suggesting bad "cut and shunt" editing, not consistent with the professional editing standards Warner Brothers Television usually releases. This is result of UK Broadcast Standards compliance edits made, as the two channels show the program multiple times across daytime, afternoon, evening, and nighttime slots.
In season one, episode thirteen, "The Bat Jar Conjecture", while discussing who to recruit to their quiz team, Raj mentions that they should get TVs Blossom on their team. The lead character on the show Blossom (1990), Mayim Balik, went on to appear on the show in the final episode of season three, and has been a regular cast member since season four.
In the one hundredth episode, where Leonard asks Penny out again, Penny is wearing the same shirt she wore in the pilot. This was probably to represent Leonard falling in love again with the same girl he did one hundred episodes before.
Howard's mother's voice was heard throughout the show, but her face has never been actually seen on-screen (she appeared very briefly on-screen in the season five finale, as the camera pans up from the rooftop, but her face was still never shown). She died after the actress who played her, Carol Ann Susi, died of cancer.
Raj, Priya, Leonard, and Bernadette are the only characters to have had both of their parents introduced in the series, prior to the season ten episode aired on Monday September 19, at 8 p.m. Eastern and 7 p.m. Central. In this episode, both of Penny's parents were introduced together.
Of all of the main characters, Leonard and Penny have had the same amount of relationships over the course of the show (Penny: Kurt, Zack, Stuart, Mike, and of course Leonard) (Leonard: Penny, Dr. Elizabeth, Priya, Leslie, and Stephanie), then Raj (Lucy and Emily), Bernadette (Glenn and Howard), and Howard (Leslie and Bernadette). Amy (Dave and Sheldon) and Sheldon (Amy).
In the season five finale, when Howard and Bernadette are getting married, during the wedding, Raj talks without drinking any alcohol, even though there is Amy, Penny, and Bernadette in the same place.
Most of the characters have evolved since their first appearance. Sheldon: He gains more feelings about women, and ever gets physical with Amy, and tells her he loves her. Howard: He is less creepy then he was in the first season, and finally settled down. Raj: He can now speak to women without being drunk. Amy: She is less like Sheldon, and not as robotic.
In season six, episode two, "The Decoupling Fluctuation", Amy mentions that she and Sheldon will be getting married in exactly four years. At the end of the season ten finale, Sheldon proposes to Amy, making this to be a somewhat valid prediction.