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The Big Bang Theory is an American sitcom created by Chuck Lorre and Bill Prady, both of whom serve as executive producers on the show along with Steven Molaro. All three also serve as head writers. It premiered on CBS on September 24, 2007 and concluded on May 16, 2019, having broadcast a total of 279 episodes over 12 seasons.

The show is primarily centered on five characters living in Pasadena, California: roommates Leonard Hofstadter and Sheldon Cooper, both physicists; Penny, a waitress and aspiring actress who later becomes a pharmaceutical representative, who lives across the hall; and Leonard and Sheldon's equally geeky and socially awkward friends and co-workers, aerospace engineer Howard Wolowitz and astrophysicist Rajesh Koothrappali. The geekiness and intellect of the four guys is contrasted for comic effect with Penny's social skills and common sense.

Over time, supporting characters have been promoted to starring roles: Leslie Winkle, a physicist colleague at California Institute of Technology and a former lover to each of Leonard and Howard; Bernadette Rostenkowski-Wolowitz, Howard's girlfriend (later his wife), a microbiologist and former part-time waitress alongside Penny; neuroscientist Amy Farrah Fowler, who joins the group after being matched to Sheldon on a dating website (and later becomes Sheldon's girlfriend); and Stuart Bloom, the cash-strapped owner of the comic book store the characters often visit.


The show's initial pilot, developed for the 2006–07 television season, was substantially different from its current form. The only characters from the initial pilot that were kept for the reshot pilot for the series were Leonard and Sheldon (portrayed by Johnny Galecki and Jim Parsons, respectively, and named after Sheldon Leonard). Althea (Vernee Watson), a character featured in the first episode, was also featured in the initial pilot and brought to the reshot pilot. The cast was rounded off by two female leads: Canadian actress Amanda Walsh as Katie, "a street-hardened, tough-as-nails, woman with a vulnerable interior" who the boys meet after she breaks up with her boyfriend and invite to live in their apartment (Katie was replaced by Penny, portrayed by Kaley Cuoco, in the second pilot); and Iris Bahr as Gilda, a scientist colleague and friend of the boys who was threatened by Katie's presence. The initial pilot used Thomas Dolby's hit "She Blinded Me with Science" as theme music.

The series was not picked up, but the creators were given an opportunity to retool the show and produce a second pilot. They brought in the remaining cast and retooled the show to its final format. The original unaired pilot has never been officially released, but it has circulated on the Internet. On the evolution of the show, Chuck Lorre said, "We did the 'Big Bang Pilot' about two and a half years ago, and it sucked... but there were two remarkable things that worked perfectly, and that was Johnny and Jim. We rewrote the thing entirely, and then we were blessed with Kaley and Simon and Kunal." As to whether the world will ever see that original pilot, maybe on a future DVD release, Lorre said, "Wow, that would be something, we will see. Show your failures..."

The first and second pilots of The Big Bang Theory were directed by James Burrows, who did not continue with the show. The reworked second pilot led to a 13-episode order by CBS on May 14, 2007. Prior to its airing on CBS, the pilot episode was distributed on iTunes free of charge. The show premiered September 24, 2007, and was picked up for a full 22-episode season on October 19, 2007. The show is filmed in front of a live audience, and is produced by Warner Bros. Television and Chuck Lorre Productions. Production was halted on November 6, 2007, due to the Writers Guild of America strike. Nearly 3 months later, on February 4, 2008, the series was temporarily replaced by a short-lived sitcom, Welcome to the Captain. The series returned on March 17, 2008 in an earlier time slot and ultimately only 17 episodes were produced for the first season. After the strike ended, the show was picked up for a second season airing in the, premiering in the same time slot on September 22, 2008. With increasing ratings, the show received a two-year renewal through the 201011 season in 2009. In 2011, the show was picked up for three more seasons. In March 2014, the show was renewed again for three more years through the 201617 season. This marks the second time the series has gained a three-year renewal.

David Saltzberg, a professor of physics and astronomy at the University of California, Los Angeles, checks scripts and provides dialogue, mathematics equations, and diagrams used as props. According to executive producer/co-creator Bill Prady, "We're working on giving Sheldon an actual problem that he's going to be working on throughout the first season so there's actual progress to the boards ... We worked hard to get all the science right."

Several of the actors in The Big Bang Theory previously worked together on Roseanne including Johnny Galecki, Sara Gilbert, and Laurie Metcalf (who plays Sheldon's mother, Mary Cooper). Additionally, Lorre was a writer on the series for several seasons.

Theme song

The Canadian alternative rock band Barenaked Ladies wrote and recorded the show's theme song, which describes the history and formation of the universe and the Earth. Ed Robertson, lead singer and guitarist in the band, was asked by Lorre and Prady to write a theme song for the show after the producers attended one of the band's concerts in Los Angeles. By coincidence, Robertson had recently read Simon Singh's book Big Bang, and at the concert, he improvised a freestyle rap about the origins of the universe. Lorre and Prady phoned Robertson shortly thereafter and asked him to write the theme song. Having been asked to write songs for other films and shows only to have them rejected in favor of other artists' songs, Robertson agreed to write the theme only after learning that Lorre and Prady had not asked anyone else.

On October 9, 2007, a full-length (1 minute and 45 seconds) version of the song was released commercially. Although some sources identify the song title as "History of Everything", the cover art for the single identifies the title as Big Bang Theory Theme. A music video was also released via special features on The Complete Fourth Season DVD and Blu-ray set. The theme was included on the band's greatest hits album, Hits from Yesterday & the Day Before, which was released on September 27, 2011.

Actors' salaries

For the first three seasons, Galecki, Parsons, and Cuoco, the three main stars of the show, received at most $60,000 per episode. The salary for the three went up to $200,000 per episode for the fourth season. Their per-episode pay went up an additional $50,000 in each of the following three seasons, culminating in $350,000 per episode in the seventh season. By season seven, the three were also receiving 0.25 point of the series' backend money. Before production began on the eighth season, the five main stars looked to renegotiate new contracts, with Galecki, Parsons, and Cuoco seeking around $1 million per episode, as well as more backend money. Contracts were signed at the beginning of August 2014, giving the three principal actors an estimated $1 million per episode for three years, with the possibility to extend for a fourth year. The deals also include larger pieces of the show, signing bonuses, production deals and advances towards the back-end.

In September 2013, Bialik and Rauch renegotiated the contracts they held since they were introduced to the series in 2010. On their old contracts, each was making $20,000–$30,000 per episode, while the new contracts doubled that, beginning at $60,000 per episode, increasing steadily to $100,000 per episode by the end of the contract, as well as adding another year for both.

In August 2014, Helberg and Nayyar renegotiated their contracts, giving them a per-episode pay in the "mid six-figure range", up from around $100,000 per episode they each received in years prior. The duo, who were looking to have salary parity with Parsons, Galecki and Cuoco, signed their contracts after the studio and producers threatened to write the characters out of the series if a deal could not be reached before the start of production on season 8.

Main cast

These actors are credited in all episodes of the series:

  • Johnny Galecki as Leonard Leakey "Lenny" Hofstadter, Ph.D – An experimental physicist with an IQ of 173, he received his PhD when he was 24 years old. His mother, Dr. Beverly Hofstadter (Christine Baranski), is a neuroscientist and psychiatrist who provided little, if any, nurturing when Leonard was growing up. Like all of the other major male characters, he is a nerd who loves video games, comic books and Dungeons & Dragons. The straight man of the series, he shares an apartment in Pasadena with colleague and friend Sheldon Cooper. Leonard is smitten with his neighbour Penny when they first meet. They briefly date at the end of season 1 and the start of season 2 and in season 3, they begin an on-again, off-again romantic relationship. Leonard also briefly dates Leslie and Dr. Stephanie Barnett (Sara Rue) in season 2, and in season 4, he becomes seriously involved with Raj's sister Priya (Aarti Mann), a successful lawyer, but she eventually returns to India and they break up in season 5 when she admits to cheating on him. In season 5, he and Penny get back together, and at the end of season 7, he proposes (not for the first time) and she accepts.
  • Jim Parsons as Sheldon Lee "Shelly" Cooper, M.A., Ph.D  – Originally from Galveston, Texas, he was a child prodigy with an eidetic memory who began college at the age of 11 (after completing the fifth grade), started graduate studies at 14, and earned a PhD at 16. A theoretical physicist researching quantum mechanics and string theory, he has two master's degrees, a PhD and a Sc.D. However, despite his IQ of 187, he finds many routine aspects of social situations and life in general difficult to understand and deal with. His father died when he was 14, and his mother, Mary (Laurie Metcalf) is a devout Christian. He also has a twin sister, Missy (Courtney Henggeler), who later has a baby in season 7. He has a poor grasp of other people's feelings and little or no understanding of nuances, often questioning others if a comment is intended as sarcasm. As a result, he is extremely tactless and acts wildly inappropriately much of the time. He is determined to have his own way, boasts of his superior intelligence and belittles the accomplishments of his friends, making him appear petty and childlike. Sheldon has an extremely ritualized way of living (e.g. sitting in the same spot on the sofa in the apartment or knocking on a door three times, each time saying the name of the person he's addressing) and a compulsion to complete things. He is also wary of germs and dislikes physical contact. Despite all these quirks, in season 4, he begins a relationship with Amy, who eventually becomes his girlfriend during season 5. In season 8, Sheldon tells Amy that he loves her.
  • Kaley Cuoco as Penny Hofstadter – An aspiring actress from a town outside of Omaha, Nebraska, Penny lives across the hall from Sheldon and Leonard. She attends casting calls and auditions, but is not very successful. To pay the bills, she is a waitress and occasional bartender at The Cheesecake Factory. Penny quits her job in season 7 and at the start of season 8 becomes a pharmaceutical representative at Bernadette's company after having given up hope of becoming a successful actress; she appreciates the financial independence the new job gives her. Penny attended, but did not graduate from a community college (she goes back to school in season 6), but has far more common sense and social awareness than the other main characters. Penny is also very untidy and frequently drinks alcohol. To date, her surname has not been revealed. She dates Leonard at the end of season 1 and the start of season 2, and in season 3, they begin an on-again, off-again romantic relationship. At the end of season 7, she accepts Leonard's proposal of marriage (after having proposed to him earlier in the season while intoxicated). Aside from Leonard, Penny has dated various men over the course of the series, which is at times brought up by Sheldon. She briefly dated Stuart in season 2, and in seasons 3 and 4 dated Zack Johnson (Brian Thomas Smith), a handsome and friendly but dim-witted guy, who she married in Las Vegas (they didn't think weddings in Las Vegas were real). In season 4, Penny, Bernadette and Amy form their own group, where they hang out in each other's apartments or go out together. Penny also has a very close friendship with Sheldon, despite his quirks. Cuoco began being credited as Kaley Cuoco-Sweeting starting with the season 7 episode "The Convention Conundrum", following her marriage to tennis player Ryan Sweeting.
  • Simon Helberg as Howard Joel "Howie" Wolowitz, M.Eng.  – An aerospace engineer, Howard is Jewish (although not always Orthodox) and lives with his mother Debbie (Carol Ann Susi). His father left both of them when he was 11 and has not heard from him since, with the exception of a letter on his eighteenth birthday, which he refused to open. Unlike Sheldon, Leonard and Raj, Howard lacks a PhD, earning him Sheldon's scorn. He defends this by pointing out that he has a master's degree in engineering from the elite MIT and that the apparatus he designs are launched into space, unlike the purely abstract work of his friends. He himself goes into space at the end of season 5, training as an astronaut and serving as a payload specialist on the International Space Station, although he often annoys his friends by constantly talking about space. He has a marked sense of humor, which Leonard and Raj occasionally appreciate. In the early seasons of the show, Howard fancies himself a ladies' man and devises outrageous pick-up lines, which have limited success with women. In season 3 he starts dating Bernadette, and although they later break up off-screen, they get back together and later get engaged in season 4 and get married at the end of season 5. In season 6, Howard finally moves out of his mother's house and into Bernadette's apartment. Howard also has a tendency to waste money on ridiculous things and often argues with Bernadette over money due to his low income, resulting in Bernadette often giving Howard an allowance.
  • Kunal Nayyar as Rajesh Ramayan "Raj" Koothrappali, Ph.D – From New Delhi, India, he works as a particle astrophysicist at Caltech. His family is very wealthy. Over the course of the series he communicates with his parents, Dr. and Mrs. V.M. Koothrappali (Brian George and Alice Amter), via webcam (they later divorce in season 8). He is very shy around women and is unable to talk to them for the first six seasons (except for his mother and his sister), unless he drinks alcohol (or at least thinks he has drunk it) or takes an experimental medication. Unfortunately, the former gives him an outrageous, unpredictable personality, while the latter causes unforeseen side effects. Even so, he often has better luck with women than his overly confident best friend, Howard. Raj also has very feminine tastes and often takes on a stereotypical female role in his close friendship with Howard, but he insists that he is not gay. During season 4, his sister Priya stays with him and becomes Leonard's girlfriend (much to Raj's annoyance). In season 6, Raj meets Lucy (Kate Micucci), who also has social anxiety, and they begin a relationship. However, Lucy ends the relationship, as she feels too pressured when he wants her to meet his friends. Afterwards, a heartbroken Raj finally speaks to Penny without having consumed alcohol. In season 7, he begins dating Emily Sweeney (Laura Spencer), a dermatologist, and their relationship later becomes exclusive. Raj also has a Yorkshire Terrier called Cinnamon, and the gang often joke about how unusually close he is with his dog.

These actors were first credited as guest stars and later promoted to main cast:

  • Sara Gilbert as Leslie Winkle, Ph.D (recurring season 1, starring season 2, guest star season 3) – a physicist who works in the same lab as Leonard. In appearance, she is essentially Leonard's female counterpart, wearing black-framed glasses and sweat jackets. She is an enemy of Sheldon's, due to their conflicting scientific theories. Though each considers the other to be intellectually inferior, Leslie is much wittier than Sheldon, regularly calls him "dumbass", and usually bests him in their repartee. Leslie has casual sex with Leonard and later Howard. Gilbert and Galecki played the on-screen couple of Darlene Connor and David Healy in Roseanne. Gilbert was promoted to a main cast member during the second season, but was demoted back to guest star status because producers could not come up with enough material for the character. Gilbert left the series after season 3 to focus her efforts on The Talk, on which she serves as executive producer for CBS.
  • Melissa Rauch as Bernadette Maryann "Bernie" Rostenkowski-Wolowitz, Ph.D (recurring season 3, starring since season 4) – a young woman with a very high-pitched voice who is initially a waitress co-worker of Penny's, paying her way through graduate school, studying microbiology. Bernadette is of Polish origin and was raised in a Catholic household. Her father Mike (Casey Sander) is a toughened retired police officer and she has four other siblings. Bernadette is introduced to Howard by Penny as a result of an agreement between Howard and Leonard that if either ever ended up with a hot girlfriend, he would get the girlfriend to introduce the other to "a hot chick". At first, they do not get along, apparently having nothing in common, until they find out that they both have overbearing mothers. During season 3, they date and then break up off-screen. They get back together and get engaged in season 4 and marry at the end of season 5. After successfully defending her doctoral thesis, she lands a high-paying research position at the end of season 4 (which becomes a source of conflict between her and Howard in later seasons). Although a generally sweet and good natured person, Bernadette has a very short temper and can be vindictive and lash out when provoked, often sounding like Howard's mother, and intimidating her colleagues. She is also shown to have a competitive streak.
  • Mayim Bialik, Ph.D, as Amy Farrah Fowler, Ph.D (guest star season 3, starring since mid-season 4) – a woman selected by an online dating site as Sheldon's perfect mate after Raj and Howard secretly set up an account using Sheldon's information, prompting Raj to comment, "We finally have proof that aliens walk among us!"Amy is from Glendale and is a fan of Little House on the Prairie. She and Sheldon initially have many similar traits, though after befriending Penny and Bernadette, Amy eventually becomes more interested in social and romantic interaction and is more socially aware than Sheldon. Once she and Sheldon meet, she becomes, as Sheldon puts it, a girl who is his friend, but not his "girlfriend". Their relationship slowly progresses up to the point where Sheldon considers her his girlfriend and tells her that he loves her. Amy's sexual frustration in her relationship with Sheldon is a recurring topic in the series. Amy also believes she and Penny are best friends ("besties", as she puts it), a sentiment that Penny does not share. Penny eventually becomes a real friend, overlooking Amy's Sheldon-like qualities. Amy's admiration for Penny has at times bordered on physical attraction. Amy has a PhD in neurobiology, and frequently uses monkeys in her research and experiments. Bialik herself has a doctorate in neuroscience. In the season 1 episode "The Bat Jar Conjecture", Raj suggests recruiting "the girl who plays TV's Blossom" (whom Bialik played) for their Physics Bowl team.
  • Kevin Sussman as Stuart David Bloom (recurring seasons 2–5, & 7, starring season 6 & 8) – the mild-mannered, under-confident individual who runs the comic book store that the guys frequent. A brilliant artist, Stuart is a graduate of the prestigious Rhode Island School of Design and though he is socially awkward, he possesses slightly better social skills than the rest of the guys. Unlike the others he is not a techno-geek. During Stuart's first appearance, the guys bring Penny along to the store, and he manages to ask her on a date. They go out a few times, until Penny mistakenly calls him "Leonard" while they are making out, leaving him devastated. In the season 4, he implies he is in financial trouble and that the comic book store is now also his home. At Howard's bachelor party, Stuart uses his toast to tell Howard how lucky he is and compares it to his own situation of living in the back of his store. In season 6, he is invited to join the guys' group while Howard is in space. At the end of season 7, the comic book store burns down and he gets a new job caring for Howard's mother. The two become close and develop a strange relationship, much to the annoyance of Howard. However, this strange relationship, is refuted by Stuart. He also briefly dates Howard's second cousin Jeanie (Kara Luiz), whom Howard lost his virginity to.

Recurring themes and elements


Much of the show focuses on science, particularly physics. The four main male characters are employed at Caltech and have science-related occupations, as do Bernadette and Amy. The characters frequently banter about scientific theories or news (notably around the start of the show), and make science-related jokes.

Science has also interfered with the characters' romantic lives. Leslie breaks up with Leonard when he sides with Sheldon in his support for string theory rather than loop quantum gravity. When Leonard joins Sheldon, Raj, and Howard on a three-month Arctic research trip, it separates Leonard and Penny at a time their relationship is budding. When Bernadette takes an interest in Leonard's work, it makes both Penny and Howard envious and results in Howard confronting Leonard, and Penny asking Sheldon to teach her physics. Sheldon and Amy also briefly end their relationship after an argument over which of their fields is superior.

David Saltzberg, who has a PhD in physics, has served as the science consultant for the show for six seasons and attends every taping. While Saltzberg knows physics, he sometimes needs assistance from Mayim Bialik, who has a PhD in neuroscience. Saltzberg sees early versions of scripts which need scientific information added to them, and he also points out where the writers, despite their knowledge of science, have made a mistake. He is usually not needed during a taping unless a lot of science, and especially the whiteboard, is involved.

Science fiction, fantasy, comic books and gaming

The four main male characters are all avid science fiction, fantasy, and comic book fans and memorabilia collectors.

Star Trek in particular is frequently referenced and Sheldon identifies strongly with the character of Spock; when he is given a used napkin signed by Leonard Nimoy as a Christmas gift from Penny he is overwhelmed with excitement and gratitude ("I possess the DNA of Leonard Nimoy?!"). Star Trek: The Original Series cast member George Takei has made a cameo, and Leonard Nimoy made a cameo as the voice of Sheldon's vintage Mr. Spock action figure (both cameos were in dream sequences). Star Trek: The Next Generation cast members Brent Spiner and LeVar Burton have had cameos as themselves, while Wil Wheaton has a recurring role as a fictionalized version of himself. All four male characters can speak Klingon to varying degrees—the opening of the episode "The Panty Piñata Polarization" shows them playing "Klingon Boggle". In the ending of the episode "The Launch Acceleration", Amy and Sheldon were seen playing doctor, with Amy dressed in a Star Trek medical uniform. In the episode "The Bakersfield Expedition", the four male leads dress up as Star Trek: The Next Generation characters for a Star Trek convention.

They are also fans of Star Wars, battlestar Galactica, and Doctor Who. In season 2, Raj likens Sheldon to C-3PO, an intelligent, yet semi-annoying protocol droid in the Star Wars series. In episode 5 of season 2, Sheldon wants to return a set of white Star Wars sheets to Pottery Barn as they are too exciting for sleeping in. In the episode "The Ornithophobia Diffusion", when there is a delay in watching Star Wars on Blu-ray, Howard complains, "If we don't start soon, George Lucas is going to change it again" (referring to Lucas' controversial alterations to the films). In one episode, while talking post-coitus, Penny quotes Yoda to Leonard: "Do. Or do not. There is no try," thrilling Leonard. In 2009, Katee Sackhoff of Battlestar Galactica appeared as herself in "The Vengeance Formulation" and in "The Hot Troll Deviation" as Howard's fantasy dream girl. Leonard likes Babylon 5, but Sheldon dismisses it as derivative. Sheldon also expresses a great liking for Joss Whedon's Firefly: he is shown to be quite upset with the Fox network for cancelling it and even incorporated the series into the Roommate Agreement. As well as this, Sheldon demonstrates knowledge of the TV series Stargate SG1: in the episode "The Cushion Saturation", he explains that the team requires a 'tactical retreat' and attempts to use an episode of Stargate SG1 to demonstrate his idea.

The four males are also fans of fantasy and make references to The Lord of the Rings and Harry Potter novels and movies. Howard can speak Sindarin, one of the two Elvish languages from The Lord of the Rings. In one episode, they find a movie prop of the One Ring and they all fight over who gets to keep it, and what to do with it. Leonard wears a Frodo Baggins costume in one episode, while Sheldon has a Gollum action figure on his desk. Raj, who is a fan of Harry Potter, makes many references to the franchise and once bought a "hand crafted" Harry Potter wand on eBay. Sheldon, in the episode "The Spoiler Alert Segmentation", tells Leonard that Dumbledore dies in Harry Potter and the Half-Blood Prince. After getting into an argument with Leonard about the spoiler, Sheldon also intentionally reveals that Dobby the elf dies in Harry Potter and the Deathly Hallows. Sheldon knows a lot about the sport of Quidditch.

Wednesday night is the group's designated "comic book night" because that is the day of the week when new comic books are released. The comic book store is run by fellow geek and recurring character Stuart. On a number of occasions, the group members have dressed up as pop culture characters, including The Flash, Aquaman, Frodo Baggins, Superman, Batman, Spock, The Doctor, Green Lantern, and Thor. As a consequence of losing a bet to Stuart and Wil Wheaton, the group members are forced to visit the comic book store dressed as Catwoman, Wonder Woman, Batgirl, and Supergirl. Sheldon often wears T-shirts depicting Batman, Superman, Flash, or Green Lantern. DC Comics announced that, to promote its comics, the company will sponsor Sheldon wearing Green Lantern T-shirts.

The male characters are also fans of the Indiana Jones series, and are willing to spend several hours in line outside of a theater to watch a special screening of Raiders of the Lost Ark with 21 seconds of new footage.

Various games have been featured, as well as referenced, on the show (e.g. World of Warcraft, Halo, Mario, etc.), including fictional games like Mystic Warlords of Ka'a (which became a reality in 2011) and Rock-paper-scissors-lizard-Spock.

Sheldon getting Penny an enchanted sword for her in a game he introduced her to, Age Of Conan

Leonard and Penny's relationship

One of the recurring plot lines is the relationship between Leonard and Penny. Leonard becomes attracted to Penny within a short time of seeing her in the pilot episode. The first season frequently featured Leonard's attraction to Penny as a basis for humor. Leonard and Penny go on a date that started the final episode of the first season and ended at the start of the second season; however, Penny quickly breaks up with Leonard because she is afraid that her educational attainments are not good enough for Leonard and that he may become bored in the first episode of season 2 ("The Bad Fish Paradigm"). Her excuse for breaking up with Leonard was when he showed her some brochures from a local community college and she took it as a knock against her schooling level and that she felt that he would only date someone with a college education.

They both date other people throughout the second season, but clearly still have feelings for each other as when Penny admits this to herself in "The Monopolar Expedition". When Leonard returns from a three-month expedition to the North Pole in the season 3 premiere, they commence a relationship which lasts for most of the season until Leonard tells Penny that he loves her and she realizes she cannot say it back, and she reluctantly breaks up with him after Wil Wheaton meddles with their relationship in order to beat Sheldon at bowling per "The Wheaton Recurrence".

Again, both Leonard and Penny go on to date other people; most notably with Leonard dating Raj's sister Priya for much of season 4. Penny has shown regret towards her decision to break up with Leonard by admitting to Raj that she misses Leonard in "The Roommate Transmogrification". She also exhibits jealousy towards Priya, especially after Priya demands Leonard stay away from her as in "The Prestidigitation Approximation". After dating Leonard, Penny also has negative reactions to her male dates who are not very intelligent after dating Zack in "The Lunar Excitation" (season 3).

Eventually, as the episodes rolled on, Leonard became more and more interested in Priya. However she seemed to become less and less interested in Leonard as they went on dating. Later in the fourth season, in "The Roommate Transmogrification" episode, Leonard is at Raj's apartment, making out with Priya, when her parents call from India, and she has Leonard leave the room as she answers the call. Unknowing of Leonard's presence or his secret relationship with Priya, her parents state that they will be so happy when Priya moves back to India. Leonard comes in, shouting out that he is shocked she is moving back to India, and assumes it means he and Priya are breaking up. Leonard goes home to his apartment, where Raj has been sleeping because of Leonard staying at Raj's apartment. Penny and Raj, while enjoying a friendly evening, got intoxicated and ended up in bed. Leonard assumes the worst when they emerge from his room, although Penny assures the group "It's not what it looks like." In the premiere of season 5 ("The Skank Reflex Analysis"), Penny learns from Raj that they did not have intercourse, but agrees not to tell anybody. Leonard forgives both Raj and Penny, and never learns the truth about what really happened.

In season five in "The Infestation Hypothesis", Leonard resumes his relationship with Priya online. It seems to work for Leonard, but he is conflicted when he meets Alice, a girl who is really into him, at the comic book store. Leonard decides he must be faithful to Priya, ending things with Alice. Leonard confesses to Priya about going out with Alice, only to discover that Priya has slept with a former boyfriend, and they break up in "The Good Guy Fluctuation".

Penny is still single and dating, though when inebriated has confessed that she regrets breaking up with Leonard, as in "The Roommate Transmogrification". In "The Ornithophobia Diffusion" (season 5), Leonard and Penny go to the movies as friends. Leonard decides that since they are no longer dating he can be honest and does not have to pay for everything or do whatever Penny wants to make Penny like him and have sex with him. The two bicker all evening and sabotage each other's attempts to chat up people in the bar. Penny decides that she likes the new, more assertive Leonard. Leonard sees this as another opportunity to grovel and try to get Penny to sleep with him, so she leaves.

On the spur of the moment in "The Recombination Hypothesis", Leonard asks Penny out on a date after he imagined what getting back with her might be like. Their real date ends successfully, and they agree to try to renew their relationship slowly in "The Beta Test Initiation". They share a kiss. During her renewed relationship with Leonard she has dismissed comments about him ever leaving or dumping her or about worrying about his unfaithfulness around other women and strippers as in the episode "The Stag Convergence". After Penny suggested having sex in "The Launch Acceleration", Leonard breaks the mood by proposing to her. They later meet and Penny has the courage to tell him "no" and not break up with him as she did two years previously when he told her that he loved her in "The Wheaton Recurrence".

In the sixth season episode, "The 43 Peculiarity", Penny finally tells Leonard that she loves him. When Sheldon's assistant Alex Jensen asks Leonard out to dinner, the dynamics of their relationship is reversed with Leonard feeling good at the extra female attention and Penny insecure about their relationship. In "The Egg Salad Equivalency', when Leonard is the object of attention of both Alex and Penny, and Leonard confesses that Alex's interest makes him feel giddy, Penny feels insecure about the relationship. To deal with her insecurities, she buys a pair of stereotypical "smart" glasses to look the part. Leonard finds this alluring, then immediately pulls her into his bedroom. In "The Tangible Affection Proof", it is Valentine's Day, and in the middle of their dinner, Penny sees a former boyfriend proposing to the woman who stole him from her. Leonard then tries to propose again, but Penny stops him cold. They make up in the end, but Leonard tells Penny that if she ever wants to get married, then she should be the one to propose. Penny does ask him to be her Valentine. By the season finale, "The Bon Voyage Reaction", she is secure enough in their relationship to send him off on an exciting four-month expedition, missing him, but not worrying about the two of them.

In the seventh season episode, "The Hofstadter Deficiency", she briefly becomes upset when Leonard does not appear to miss her whatsoever while on the expedition, and starts to get close to Sheldon. This all changes when Leonard comes home rather early and secretly stays with her until his expected arrival, only to be discovered by Sheldon the day before. Over the course of the season, they continue to get closer and closer. Finally, in the penultimate episode "The Gorilla Dissolution", Penny admits that she has had an epiphany and realizes she should marry Leonard. Leonard is initially in denial, considering that she has rejected all such advances in the past, but eventually is able to convince him. He proposes to her mere seconds later (with a ring that he had kept in his pocket for years), and she says yes. They get married in Season 9 and in the series finale, expect their 1st child.

Sheldon and Amy's relationship

A storyline that began in the third season finale is the relationship of Sheldon and Amy Farrah Fowler, PhD, a neurobiologist. Raj and Howard found her as a possible match for Sheldon through an online dating service (without Sheldon's knowledge) in "The Lunar Excitation". By Sheldon's own admission, she is most like him by any standard to his mother in "The Zazzy Substitution". Like him, she has previously avoided relationships (whether romantic or otherwise is unclear, although conversation in numerous episodes indicates she was a social outcast), and only participated in the online dating herself to fulfill an agreement with her mother that she date at least once a year (in exchange, her mother does not discuss Amy's lack of a love life, plus she gains use of her mother's George Foreman Grill) as told to Penny on her date with Sheldon during "The Robotic Manipulation".

During the four months of their relationship (taking place off-screen between seasons 3 and 4), they communicated on a daily basis via text messages, email, and Twitter, but never saw each other in person per "The Robotic Manipulation". Sheldon, however, did not consider Amy his girlfriend. Penny later suggests that they should go on a date and ends up driving them and having dinner with them in "The Robotic Manipulation". Penny refers to Sheldon and Amy collectively as "Shamy" in "The Shiny Trinket Maneuver", but discontinues this after Amy indicates that she dislikes that nickname.

In "The Agreement Dissection", Amy, Penny, and Bernadette decide to take Sheldon dancing. Sheldon dances only with Amy, which he does not mind. He later follows Amy back to her apartment. They talk for a few minutes before she kisses him on the lips. Instead of getting annoyed, Sheldon just says "Fascinating." This is a catalyst for later events and clash of personalities in the relationship of the more scientific, masculine Sheldon, and the more socially open, feminine, and annoyed Amy.

In "The Flaming Spittoon Acquisition", after Amy agrees to go on a date with Stuart, Sheldon asks Amy to be his girlfriend, interrupting her date with Stuart, with the stipulation that no other changes occur in their current relationship. Amy says yes, and Sheldon then lets her and Stuart continue their date. The same night and episode, he draws up "The Relationship Agreement" to verify the ground rules of him as her boyfriend and vice versa (similar to his "Roommate Agreement" with Leonard). Amy agrees but later regrets not having a lawyer read through it.

After Penny and Bernadette go wedding shopping without Amy in "The Isolation Permutation", Sheldon comforts a depressed Amy by cuddling with her on her couch; however, Amy first suggests that they have coitus. While cuddling, Amy suggests quite bluntly she is eager for more, pointing out to him that "Second base is right there."

In the episode "The Launch Acceleration", Amy says she would like to do an experiment using her neurobiology bag of tricks to increase Sheldon's feelings toward her. Sheldon is skeptical, but goes with it. Amy says she would like to put on some romantic dinner music, and ends up putting on the Super Mario Bros. theme song. Sheldon catches on, and calls Amy out on the fact that she is trying to engage his feelings of the happiest times of his life as he starts to hum along. This is further reinforced when she offers Sheldon his favorite drink, Strawberry Quik. She also prepared "spaghetti with little pieces of hot dog cut up" for dinner, which is Sheldon's favorite since his mother used to make it for him. Sheldon is thrilled, and says they should do this more often – instantly realizing he has been caught in Amy's "trap" as Amy stands next to him with a big smile. At the end of the episode, they were playing doctor "Star Trek style" (Amy dressed in Star Trek attire). Amy's actions seem to work on Sheldon, who is not happy about it but makes no attempt to stop her. In the final fifth season episode "The Countdown Reflection", Sheldon takes Amy's hand as Howard is launched into space. Amy glances over at him looking quite surprised.

In the sixth season premiere episode "The Date Night Variable", after a dinner in which Sheldon fails to live up to this expectation, Amy gives Sheldon an ultimatum that their relationship is over unless he tells her something from his heart. Sheldon gives a romantic speech about his new and conflicting emotions, only to reveal that he quoted the first Spider-Man movie. Despite this, Amy accepts it. In "The Fish Guts Displacement", Sheldon takes care of a sick Amy. Sheldon rubs VapoRub on her chest, unknowingly arousing Amy. The following day, Sheldon is angry because her throat culture showed that she was no longer sick, and that Amy was pretending to be sick after initially feeling better. Amy apologizes, but Sheldon thinks that she needs to be punished (which Sheldon thinks in terms of corporal punishment, but Amy thinks in terms of erotic spanking). The episode ends with Sheldon placing Amy across his knees for a spanking, which Amy also enjoys to some mood music.

In "The Cooper/Kripke Inversion", Penny asks Sheldon whether he would ever consider a sexual relationship with Amy. Sheldon states that he has been working on his discomfort about physical contact and admits that "it's a possibility" that he could one day get physical with Amy. In "The Tangible Affection Proof", it is Valentine's Day, and Sheldon keeps a gift that he was supposed to give Amy, but Amy gives Sheldon the perfect Valentine's Day by staying in his apartment and doing exactly what he wants to do: watch a favorite movie and have pizza. Sheldon makes Amy his emergency point of contact, which sends her to tears as she is now responsible for his well-being. In "The Love Spell Potential", the girls participate in a game of Dungeons & Dragons] along with the boys. Penny says that Sheldon and Amy's game characters should "do it" in the game, believing that Sheldon and Amy would not get physical anytime soon. Bernadette then casts a love spell on both of them. Amy gets upset and leaves and Sheldon is sent to look after her. Amy tells him that their friends think that their relationship is a joke and asks him if they are ever going to get intimate. Sheldon does not think that they are a joke, explaining that he never thought about intimacy with anyone before Amy, and says he would not rule it out. Sheldon then plays out the love potion scenario with Amy, much to her delight - but in the privacy of Sheldon's bedroom and with no physical contact between them.

In "The Locomotive Manipulation", Amy plans a romantic Valentine's Day with Sheldon at a bed-and-breakfast on a vintage train with Bernadette and Howard. Sheldon meets a fellow train enthusiast and spends most of the trip talking with him instead of Amy. Amy gets angry and confronts Sheldon, furious about how insensitive he is to her feelings of wanting a romantic vacation. Sheldon accuses Amy of trying to force a romantic atmosphere by manipulating him with his passion for trains. In a fit of sarcasm in being romantic, Sheldon kisses Amy for the first time, only to discover that he enjoys the feeling.

Consequently, Sheldon slowly starts to open up over the course of the rest of the season, and starts having a more intimate relationship with Amy. However, in the season finale, Sheldon leaves town temporarily to cope with all the changes going on in that episode. This leaves Amy heartbroken, and in her suffering she comically attacks Leonard, shouting "How could you let him go?"

In the season 8 episode "The Prom Equivalency", Amy and Bernadette organize a prom do over, in the roof of the guy's apartment building. Sheldon becomes scared of the prom rituals that Penny and Leonard told him about, like losing your virginity on prom night, and hides in his room to avoid going. Amy stands outside Sheldon's door, and when she is about to leave Sheldon leaves his room and explains why he left. He tells Amy that he thought she looked pretty in her prom dress and started to panic, worrying that he could possibly give in to his urges even though he isn't ready. Amy reassures Sheldon that even though she is always hoping that he will one day want to be physically intimate, she just wants to have a good time at prom. Right before they leave, Amy stops Sheldon and tries to tell him she loves him, but he doesn't have to say it back if he is not ready. She continues to ramble and Sheldon stops her by saying that he loves her too, understanding what she was about to say. Amy is shocked and ecstatic by what Sheldon just confessed and therefore has a panic attack, just like Sheldon earlier on in the episode.


A recurrent theme is Sheldon's conflict with his devout mother, Mary, who is a creationist, and whose beliefs occasionally clash with Sheldon's irreligion and vision of evolution. In "The Lunar Excitation", Sheldon mentions his promise to his mother to attend church once a year. Also, in "The Mommy Observation", Sheldon refers to his mother's religious beliefs as "pre-Enlightenment mythology". Evidence of Sheldon's irreligion is seen when he is heard exclaiming "Why hast thou forsaken me, o deity whose existence I doubt?" upon the discovery that his World of Warcraft account has been hacked. According to Raj, Sheldon also begged the deity in which he did not believe to kill him quickly upon getting food poisoning at the Rose Bowl. On the other hand Sheldon says he wishes "to employ his rare and precious mental faculties to tear the mask off nature and stare at the face of God." Sheldon's religious upbringing leads to moments of religious interjection when his emotions are high – on one occasion, he happily exclaims "Thank you, Jesus!" when he scores a strike in bowling, quickly adding "As my mother would say In addition, he frequently says the word "Lord" when he is upset.

At the same time, a running gag in the series is the fact that Howard, who is Jewish and Raj, who is Hindu, frequently defy many of their respective religious customs without worry, such as their constant flouting of dietary prohibitions. They both also tend to give each other grief about them. In the episode "The Financial Permeability", Raj quotes from the book of Leviticus after Howard eats pork, and Howard counters with the fact that he keeps quiet when Raj eats a Whopper. Nevertheless, they are seen to be semi-observant. Raj, for example, occasionally mentions reincarnation and explains his belief in karma, stating that he believes it to be "practically Reaction Newtonian – for every action there is an equal and opposite reaction." Howard celebrates at least some Jewish holidays, once refused to pray in a Christian church so he does not "burst into flames" and also wore tattoo sleeves instead of getting real tattoos so he "still can be buried in a Jewish cemetery".

Another frequent theme is Penny's confidence in supernatural beliefs that frequently conflict with Leonard and Sheldon's scientific beliefs and knowledge, such as ghosts, astrology, psychics and voodoo. This is first seen in the Pilot, when she makes reference to her being a Sagittarius, to which Sheldon criticises her belief in astrology, but is most frequently seen in an episode in which she and Leonard had a falling out over the validity of psychics.

Howard's mother

In scenes set at Howard's home in which he interacts with his never-seen mother (voiced by Carol Ann Susi until her death), he always does so via shouting conversations between the rooms in his house, and she similarly interacts with other characters in this manner, though she did appear momentarily in the overhead photo of Howard and Bernadette's wedding and from the side in "The Spoiler Alert Segmentation" episode, though her face was not shown. She reflects the Jewish mother stereotype in some ways, such as being overly controlling of Howard's adult life and sometimes trying to make him feel guilty about causing her trouble. She is dependent on Howard, as she requires him to help her with her wig and makeup in the morning. Howard in turn is attached to his mother to the point where she still cuts his meat for him, takes him to the dentist, does his laundry and "grounds" him when he returns home after briefly moving out. Until Howard's marriage to Bernadette in the fifth season finale, Howard's former living situation led Leonard's psychiatrist mother to speculate that he may suffer from some type of pathology, and Sheldon to refer to their relationship as Oedipal. Her tendency to communicate with Howard by shouting between rooms has led Bernadette and Raj to do impressions of her, and Bernadette to attempt to communicate with her in one episode by imitating her style of shouting.

Vanity card

Like most shows created by Chuck Lorre, The Big Bang Theory ends by showing a vanity card written by Lorre after the credits, followed by the Warner Bros. Television closing logo. These cards are archived on Lorre's website.


Critical reception

The Big Bang Theory initially received mixed reviews and originally received a score of 57/100 from review aggregator Metacritic, indicating "mixed or average reviews". Tom Shales of The Washington Post gave the show a positive review, saying "Big Bang is the funniest new sitcom of the season". Robert Bianco of USA Today also gave the show a positive review, saying "This may not be the sitcom breakthrough for which we've all been hoping, but Lorre has produced a first episode that leaves you eager to try the second". Robert Lloyd of the Los Angeles Times gave a mixed review, stating "It's just the same joke endlessly repeated – the everyday translated into geek-speak, and the obscure and difficult treated as if it were common knowledge". Mike Duffy of the Detroit Free Press gave a negative review, stating "This is by far the least charming—the lame, leering sitcom tales of two brainiac losers goofily smitten by the babelicious girl next door. It's about as witty as a pocket protector".

James Chamberlin of IGN gave season 2 an 8.4 out of 10 score, saying, "This may be a show about nerds, but you don't have to be a brainiac to enjoy it." Amanda Sloane Murray, writing for the same website, gave season three nine out of 10, describing it as "more intelligent than most sitcoms in recent memory". The American Film Institute ranked season three one of the 10 best television seasons of 2009.

Leigh H. Edwards of PopMatters gave season 4 an 8/10, commenting "The comic commentary may be poking gentle fun at nerds, but the real target of the show's sharp satire is the arbitrary, self-serving stupidity of mainstream culture". On the other hand Brian Tallerico of Hollywood Chicago panned the series writing: "There's nothing here that seems even remotely original."

Tom Gliatto of People remarked of season 5, "It's bright and obvious as a cartoon yet written with a clean, precise patter of jokes. It's also very well cast".

Kate Ward of Entertainment Weekly gave season 6 a 91/100, remarking "Bialik manages to steal scenes from Parsons as if she's been with the crew since, well, the big bang". Robert Bianco continued to give a positive review, noting "When it comes to making viewers catch their breath from laughing, no show tops Big Bang, and that's an ability that should never be undervalued in a comedy. Bang is one of those rare series where just thinking about some of the plots is enough to make you laugh all over again". On the other hand, June Thomas of Slant Magazine gave the season a negative review, calling it "disappointing".

U.S. standard ratings

The Big Bang Theory has been highly rated since its premiere. When the third season premiered on September 21, 2009, The Big Bang Theory ranked as CBS's highest-rated show of that evening in the adults 18–49 demographic (4.6/10) along with a then-series-high 12.83 million viewers. After the first three seasons aired at different times on Monday nights, CBS moved the show to Thursdays at 8:00 ET for the 2010–2011 schedule, to be in direct competition with NBC's Comedy Block and Fox's American Idol (then the longest reigning leading primetime show on U.S. television from 2004 to 2011). During its fourth season, it became television's highest rated comedy, just barely beating out eight-year champ Two and a Half Men. However, in the age 18–49 demographic (the show's target age range), it was the second highest rated comedy, behind ABC's Modern Family. The fifth season opened with viewing figures of over 14 million.

The sixth season boasts some of the highest-rated episodes for the show so far, with a then-new series high set with "The Bakersfield Expedition", with 20 million viewers, a first for the series, which along with NCIS, made CBS the first network to have two scripted series reach that large an audience in the same week since 2007. In the sixth season, the show became the highest rated and viewed scripted show in the 18–49 demographic, trailing only the live regular NBC Sunday Night Football coverage, and was third in total viewers, trailing NCIS and Sunday Night Football. Season seven of the show opened strong, continuing the success gained in season six, with the second episode of the premiere, "The Deception Verification", setting the new series high in viewers with 20.44 million.

Showrunner Steve Molaro, who took over from Bill Prady with the sixth season, credits some of the show's success to the sitcom's exposure in off-network syndication, particularly on TBS, while Michael Schneider of TV Guide attributes it to the timeslot move two seasons earlier. Chuck Lorre and CBS Entertainment president Nina Tassler also credit the success to the influence of Molaro, in particular the deepening exploration of the firmly established regular characters and their interpersonal relationships, such as the on-again, off-again relationship between Leonard and Penny. Throughout much of the 2012–13 season, The Big Bang Theory placed first in all of syndication ratings, receiving formidable competition from only Judge Judy and Wheel of Fortune (first-run syndication programs). By the end of the 2012–13 television season, The Big Bang Theory had dethroned Judge Judy as the ratings leader in all of syndicated programming with 7.1, Judy descending to second place for that season with a 7.0. The Big Bang Theory did not place first in syndication ratings for the 2013-14 television season, beaten out by Judge Judy.

Season Timeslot (ET) Season premiere Season finale TV season No. of
Rank Avg. viewers
(in millions)
Most watched episode Viewers
1 Monday 8:30 p.m. (September 24 – November 12, 2007)
Monday 8:00 p.m. (March 17 – May 19, 2008)
September 24, 2007 May 19, 2008 2007–08 17 68 8.31 "The Dumpling Paradox" 9.68
2 Monday 8:00 p.m. (September 22, 2008 – May 11, 2009)
Monday 9:30 p.m. (February 9, 2009)
September 22, 2008 May 11, 2009 2008–09 23 44 10.00 "The Maternal Capacitance" 13.11
3 Monday 9:30 p.m. (September 21, 2009 – May 24, 2010)
Monday 9:00 p.m. (May 3, 2010)
September 21, 2009 May 24, 2010 2009–10 23 12 14.14 "The Precious Fragmentation" 16.32
4 Thursday 8:00 p.m. September 23, 2010 May 19, 2011 2010–11 24 15 13.14 "The Robotic Manipulation" 14.04
5 September 22, 2011 May 10, 2012 2011–12 24 8 15.82 "The Friendship Contraction" 16.54
6 September 27, 2012 May 16, 2013 2012–13 24 3 18.68< "The Bakersfield Expedition" 20.00<
7 September 26, 2013 May 15, 2014 2013–14 24 2 19.96 "The Deception Verification" 20.44
8 Monday 8:00 p.m. (Sept. 22, 2014 – October 20, 2014)
Thursday 8:00 p.m. (October 30, 2014 –)
September 22, 2014 2014–15 24

UK distribution and ratings

The show made its UK debut on Channel 4 on February 14, 2008 bringing in an average audience of 1 million viewers. The second episode, shown the following week, also received 1 million. For the third episode, an average of 1.1 million tuned in. The show is also shown as a 'first-look' on Channel 4's digital offshoot E4, and brings in 400,000 viewers on average. The fifth episode received 880,000 viewers. After the first five episodes, the average number of viewers continues to hover around the 1 million mark. Episode 13 was watched by 1.3 million viewers and was the most watched episode.

In December 2008, Virgin Media made the first nine episodes of the first season available to watch on its TV Choice On Demand service, and the rest of season 1 was made available in January 2009.

As of December 5, 2009, all 23 episodes of season 2 were also made available on Virgin Media TV Choice On Demand Service, but both seasons have now been removed.

Season 3 began airing on E4 and E4 HD on December 17, 2009 at 9:00 p.m. but was on hiatus between February 25 and May 6, 2010, when the final 11 episodes of the season aired.

Season 4 began airing on E4 on November 4, 2010, at 9:00 p.m. It drew 877,000 viewers, with a further 256,000 watching on the E4+1 hour service. This gave the show an overall total of 1.13 million viewers, making it E4's most watched program for that week. E4 broke season four after 12 episodes in January 2011. Season 4 returned on E4 from June 30, 2011, for the remaining episodes.

Season 5 began airing in 2012 at 8:00 p.m. as part of E4 Comedy Thursdays, as a lead-in to Perfect Couples. Episode 19, the highest-viewed episode of the season, attracted 1.4 million viewers.

Season 6 premiered on E4 on November 15, 2012, with 1.89 million viewers and a further 469,000 on the time shift channel, bringing the total to 2.31 million – E4's highest viewing ratings of 2012, and the highest the channel has received since June 2011.

Season 7 premiered on E4 on October 31, 2013 at 8:30pm. Season 8 premiered on E4 on October 23, 2014 at 8:30pm.

Canadian ratings

The Big Bang Theory started off quietly in Canada, but managed to garner major success in later seasons. The Big Bang Theory is telecast throughout Canada via the CTV Television Network in simultaneous substitution with cross-border CBS affiliates. Now immensely popular in Canada, The Big Bang Theory is also rerun daily on the Canadian cable channel The Comedy Network.

The season 4 premiere garnered an estimated 3.1 million viewers across Canada. This is the largest audience for a sitcom since the series finale of Friends. The Big Bang Theory has pulled ahead and has now become the most-watched entertainment television show in Canada.


Main article: List of The Big Bang Theory episodes


The Big Bang Theory premiered in the United States on September 24, 2007 on CBS. The series debuted in Canada on CTV in September 2007. The Canadian network Vrak.TV began airing a version of the series dubbed in French on August 28, 2012. On March 12, 2008, Nine Network in Australia debuted the series. Broadcast of Big Bang Theory on Irish networks 3e and RTÉ Two began September 9, 2008. On February 14, 2008, the series debuted in the United Kingdom on channels E4 (HD) and Channel 4. New Zealand network TV2 started broadcasting the series September 17, 2008.

DVD/Blu-ray releases

DVD and Blu-ray release dates for The Big Bang Theory
Name Release dates Ep # Additional Information
Region 1 Region 2 Region 4
The Complete First Season September 2, 2008 January 12, 2009 April 3, 2009 17 The three-disc box set includes all 17 episodes. The one extra feature is an 18-minute short entitled "Quantum Mechanics of The Big Bang Theory: Series Cast and Creators on Why It's Cool to Be a Geek". Running Time: 355 minutes.
The Complete Second Season September 15, 2009 October 19, 2009 March 3, 2010 23 The four-disc box set includes all 23 episodes. Special features include a gag reel, "Physicist to the Stars: Real-Life Physicist/UCLA professor David Saltzberg's consulting relationship to the Show", and "Testing the Infinite Hilarity Hypothesis in relation to the Big Bang Theory: Season 2's Unique Characters and Characteristics". Running Time: 481 minutes.
The Complete Third Season September 14, 2010 September 27, 2010 October 13, 2010 23 The three-disc box set includes all 23 episodes. Special features include a set tour with Simon Helberg and Kunal Nayyar, an inside look on the third season and a gag reel. This is the first time a season of the show was released on Blu-ray Disc in a two-disc set, in conjunction with the DVD release. Running Time: 472 minutes.
The Complete Fourth Season September 13, 2011 September 26, 2011 October 5, 2011 24 The three-disc box set includes all 24 episodes. Special features include the story behind the show's theme song with Barenaked Ladies, along with the music video for the theme song, cast interviews with each other, and a gag reel. Running time: 529 minutes. Also available on Blu-ray as a two-disc set, with an exclusive behind-the-scenes look at the taping of "The Wildebeest Implementation".
The Complete Fifth Season September 11, 2012 September 3, 2012 October 1, 2012 24 The three-disc box set includes all 24 episodes. Special features include "The Big Bang Theory at 100", a featurette on the show's 100th episode, "The Big Bang Theory's Laws of Reflection", "Professors of Production", and a gag reel. Running time: 552 minutes. Also available on Blu-ray/DVD combo pack with UltraViolet download.
The Complete Sixth Season September 10, 2013 September 2, 2013 September 18, 2013 24 The three-disc box set contains all 24 episodes. Special features include "The Big Bang Theory: The Final Comedy Frontier", where astronauts Buzz Aldrin and Mike Massimino join the cast to analyze Howard's space mission, "Houston, We Have a Sitcom", "Electromagnetism: The Best Relationship Moments in Season 6", "The Big Bang Theory at Paleyfest 2013", and a gag reel. Running time: 477 minutes. Also available on Blu-ray/DVD combo pack with UltraViolet download.
  • Despite the third, fourth, fifth, and sixth seasons receiving Blu-ray releases in conjunction with their DVD releases, the first and second seasons were only available on DVD upon their time of release. Warner Bros. has since released the first two seasons on Blu-ray/DVD combo packs with UltraViolet downloads on July 10, 2012. All of the episodes from seasons 1 & 2 on Blu-ray received newly remastered surround-sound audio, with the first season sporting a never-before-seen gag reel, which was not included during the initial first season DVD release.

Scientist cameos

As the theme of the show revolves around science, many distinguished and high profile scientists have appeared as guest stars on the show. Famous astrophysicist and Nobel laureate George Smoot had a cameo appearance in episode 17 "The Terminator Decoupling", of the second season. Theoretical physicist Brian Greene also appeared on the show in "The Herb Garden Germination", episode 20 of the fourth season. Astrophysicist, science populizer, and physics outreach specialist, Neil deGrasse Tyson appeared in "The Apology Insufficiency", episode 7 of the fourth season. Cosmologist Stephen Hawking made a short guest appearance in the fifth-season episode "The Hawking Excitation" on April 5, 2012. In the episode he meets Sheldon Cooper and points out a mistake in Sheldon's new Higgs boson analysis. Hawking also speaks on the phone at the end of the episode "The Extract Obliteration" with Sheldon, but is not seen on-camera. In the end of season 5 and the beginning of season 6 NASA astronaut Michael J. Massimino was featured as himself multiple times in the role of Howard's fellow astronaut.

Online media

Warner Bros. Television controls the online rights for the show. Full episodes are available at, while short clips and recently aired full episodes are available on cbs.com. In Canada, recent episode(s) and pictures are available on CTV.ca. After the show has aired in New Zealand the shows are available in full online at TVNZ's on demand web service.


In May 2010, it was reported that the show had been picked up for syndication, mainly among Fox's owned and operated stations and other local stations, with Warner Bros. Television's sister cable network TBS holding the show's cable syndication rights. Broadcast of old shows began airing in September 2011. TBS now airs the series in primetime on Tuesdays, Wednesdays, and Thursdays, with evening broadcasts on Saturdays (TBS's local sister station in Atlanta also holds local weeknight rights to the series). Although details of the syndication deal have not been revealed, it was reported the deal "set a record price for a cable off-network sitcom purchase". CTV holds national broadcast syndication rights in Canada, while sister cable network The Comedy Network holds cable rights.

Awards and nominations

In August 2009, the sitcom won the best comedy series TCA award and Jim Parsons (Sheldon) won the award for individual achievement in comedy. In 2010, the show won the People's Choice Award for Favorite Comedy, while Parsons won a Primetime Emmy Award for Outstanding Lead Actor in a Comedy Series. On January 16, 2011, Parsons was awarded a Golden Globe for Best Performance by an Actor in a Television Series – Comedy or Musical, an award that was presented by co-star Kaley Cuoco. On September 18, 2011, Parsons was again awarded an Emmy for Best Actor in a Comedy Series. On January 9, 2013, the show won People's Choice Award for Favorite Comedy for a second time. On August 25, 2014, Jim Parsons was awarded an Emmy for Best Actor in a Comedy Series.

The Theorists

Through the use of his vanity cards at the end of episodes, Lorre alleged that the program had been plagiarized by a show produced and aired in Belarus. Officially titled Теоретики (The Theorists), the show features "clones" of the main characters, a similar opening sequence, and what appears to be a very close Russian translation of the scripts.

However, no legal action was required to end production of the other show: as soon as the word got out that the show was unlicensed, the actors quit and the producers cancelled it. Dmitriy Tankovich (who plays Leonard's counterpart, "Seva") said in an interview: "I'm upset. At first, the actors were told all legal issues were resolved. We didn't know it wasn't the case, so when the creators of The Big Bang Theory started talking about the show, I was embarrassed. I can't understand why our people first do, and then think. I consider this to be the rock bottom of my career. And I don't want to take part in a stolen show".


External Links

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The Big Bang TheoryYoung SheldonVideo
Main Characters: Leonard HofstadterSheldon CooperPenny HofstadterHoward WolowitzRajesh KoothrappaliAmy Farrah FowlerBernadette Rostenkowski-WolowitzStuart BloomEmily SweeneyLeslie Winkle

Recurring Characters: Barry KripkeWil WheatonAltheaKurtEric GablehauserMary CooperDebbie WolowitzV.M. KoothrappaliMrs. KoothrappaliMikeStephanie BarnettBeverley HofstadterPresident SiebertZack JohnsonPriya KoothrappaliWyattMike RostenkowskiMrs. RostenkowskiAlex JensenJanine DavisLucyProfessor ProtonDavid GibbsClaireStephen HawkingAlfred HofstadterColonel Richard WilliamsDenise
Minor Characters: Christy VanderbelLalita GuptaToby LoobenfeldDennis KimDimitriMissy CooperBlainTomOctaviaMariaLourdesRamona NowitzkiKathy O'BrianDavid UnderhillAliciaMikaylaCaptain SweatpantsLonely LarryDr. CrawleyBethanySarahSkeeterProfessor LaughlinAbbyMarthaOfficer HackettSandyGlenVenkatesh KoothrappaliSebastianLouie/LouiseJoyce KimMrs. GundersonJoyMrs. FowlerAngela PageProfessor GlennMrs. LathamTodd ZarneckiSusanRandallColonel Richard Williams

Season 1: PilotThe Big Bran HypothesisThe Fuzzy Boots CorollaryThe Luminous Fish EffectThe Hamburger PostulateThe Middle-Earth ParadigmThe Dumpling ParadoxThe Grasshopper ExperimentThe Cooper-Hofstadter PolarizationThe Loobenfeld DecayThe Pancake Batter AnomalyThe Jerusalem DualityThe Bat Jar ConjectureThe Nerdvana AnnihilationThe Porkchop IndeterminacyThe Peanut ReactionThe Tangerine Factor

Season 2: The Bad Fish ParadigmThe Codpiece TopologyThe Barbarian SublimationThe Griffin EquivalencyThe Euclid AlternativeThe Cooper-Nowitzki TheoremThe Panty Piñata PolarizationThe Lizard-Spock ExpansionThe White Asparagus TriangulationThe Vartabedian ConundrumThe Bath Item Gift HypothesisThe Killer Robot InstabilityThe Friendship AlgorithmThe Financial PermeabilityThe Maternal CapacitanceThe Cushion SaturationThe Terminator DecouplingThe Work Song NanoclusterThe Dead Hooker JuxtapositionThe Hofstadter IsotopeThe Vegas RenormalizationThe Classified Materials TurbulenceThe Monopolar Expedition
Season 3: The Electric Can Opener FluctuationThe Jiminy ConjectureThe Gothowitz DeviationThe Pirate SolutionThe Creepy Candy Coating CorollaryThe Cornhusker VortexThe Guitarist AmplificationThe Adhesive Duck DeficiencyThe Vengeance FormulationThe Gorilla ExperimentThe Maternal CongruenceThe Psychic VortexThe Bozeman ReactionThe Einstein ApproximationThe Large Hadron CollisionThe Excelsior AcquisitionThe Precious FragmentationThe Pants AlternativeThe Wheaton RecurrenceThe Spaghetti CatalystThe Plimpton StimulationThe Staircase ImplementationThe Lunar Excitation
Season 4: The Robotic ManipulationThe Cruciferous Vegetable AmplificationThe Zazzy SubstitutionThe Hot Troll DeviationThe Desperation EmanationThe Irish Pub FormulationThe Apology InsufficiencyThe 21-Second ExcitationThe Boyfriend ComplexityThe Alien Parasite HypothesisThe Justice League RecombinationThe Bus Pants UtilizationThe Love Car DisplacementThe Thespian CatalystThe Benefactor FactorThe Cohabitation FormulationThe Toast DerivationThe Prestidigitation ApproximationThe Zarnecki IncursionThe Herb Garden GerminationThe Agreement DissectionThe Wildebeest ImplementationThe Engagement ReactionThe Roommate Transmogrification
Season 5: The Skank Reflex AnalysisThe Infestation HypothesisThe Pulled Groin ExtrapolationThe Wiggly Finger CatalystThe Russian Rocket ReactionThe Rhinitis RevelationThe Good Guy FluctuationThe Isolation PermutationThe Ornithophobia DiffusionThe Flaming Spittoon AcquisitionThe Speckerman RecurrenceThe Shiny Trinket ManeuverThe Recombination HypothesisThe Beta Test InitiationThe Friendship ContractionThe Vacation SolutionThe Rothman DisintegrationThe Werewolf TransformationThe Weekend VortexThe Transporter MalfunctionThe Hawking ExcitationThe Stag ConvergenceThe Launch AccelerationThe Countdown Reflection
Season 6: The Date Night VariableThe Decoupling FluctuationThe Higgs Boson ObservationThe Re-Entry MinimizationThe Holographic ExcitationThe Extract ObliterationThe Habitation ConfigurationThe 43 PeculiarityThe Parking Lot EscalationThe Fish Guts DisplacementThe Santa SimulationThe Egg Salad EquivalencyThe Bakersfield ExpeditionThe Cooper/Kripke InversionThe Spoiler Alert SegmentationThe Tangible Affection ProofThe Monster IsolationThe Contractual Obligation ImplementationThe Closet ReconfigurationThe Tenure TurbulenceThe Closure AlternativeThe Proton ResurgenceThe Love Spell PotentialThe Bon Voyage Reaction
Season 7: The Hofstadter InsufficiencyThe Deception VerificationThe Scavenger VortexThe Raiders MinimizationThe Workplace ProximityThe Romance ResonanceThe Proton DisplacementThe Itchy Brain SimulationThe Thanksgiving DecouplingThe Discovery DissipationThe Cooper ExtractionThe Hesitation RamificationThe Occupation RecalibrationThe Convention ConundrumThe Locomotive ManipulationThe Table PolarizationThe Friendship TurbulenceThe Mommy ObservationThe Indecision AmalgamationThe Relationship DiremptionThe Anything Can Happen RecurrenceThe Proton TransmogrificationThe Gorilla DissolutionThe Status Quo Combustion
Season 8: The Locomotion InterruptionThe Junior Professor SolutionThe First Pitch InsufficiencyThe Hook-up ReverberationThe Focus AttenuationThe Expedition ApproximationThe Misinterpretation AgitationThe Prom EquivalencyThe Septum DeviationThe Champagne ReflectionThe Clean Room InfiltrationThe Space Probe DisintegrationThe Anxiety OptimizationThe Troll ManifestationThe Comic Book Store RegenerationThe Intimacy AccelerationThe Colonization ApplicationThe Leftover ThermalizationThe Skywalker IncursionThe Fortification ImplementationThe Communication DeteriorationThe Graduation TransmissionThe Maternal CombustionThe Commitment Determination
Season 9: The Matrimonial MomentumThe Separation OscillationThe Bachelor Party CorrosionThe 2003 ApproximationThe Perspiration ImplementationThe Helium InsufficiencyThe Spock ResonanceThe Mystery Date ObservationThe Platonic PermutationThe Earworm ReverberationThe Opening Night ExcitationThe Sales Call SublimationThe Empathy OptimizationThe Meemaw MaterializationThe Valentino SubmergenceThe Positive Negative ReactionThe Celebration ExperimentationThe Application DeteriorationThe Solder Excursion DiversionThe Big Bear PrecipitationThe Viewing Party CombustionThe Fermentation BifurcationThe Line Substitution SolutionThe Convergence-Convergence
Season 10: The Conjugal ConjectureThe Military MiniaturizationThe Dependence TranscendenceThe Cohabitation ExperimentationThe Hot Tub ContaminationThe Fetal Kick CatalystThe Veracity ElasticityThe Brain Bowl IncubationThe Geology ElevationThe Property Division CollisionThe Birthday SynchronicityThe Holiday SummationThe Romance RecalibrationThe Emotion Detection AutomationThe Locomotion ReverberationThe Allowance EvaporationThe Comic-Con ConundrumThe Escape Hatch IdentificationThe Collaboration FluctuationThe Recollection DissipationThe Separation AgitationThe Cognition RegenerationThe Gyroscopic CollapseThe Long Distance Dissonance
Season 11: The Proposal ProposalThe Retraction ReactionThe Relaxation IntegrationThe Explosion ImplosionThe Collaboration ContaminationThe Proton RegenerationThe Geology MethodologyThe Tesla RecoilThe Bitcoin EntanglementThe Confidence ErosionThe Celebration ReverberationThe Matrimonial MetricThe Solo OscillationThe Separation TriangulationThe Novelization CorrelationThe Neonatal NomenclatureThe Athenaeum AllocationThe Gates ExcitationThe Tenant DisassociationThe Reclusive PotentialThe Comet PolarizationThe Monetary InsufficiencyThe Sibling RealignmentThe Bow Tie Asymmetry
Season 12: The Conjugal ConfigurationThe Wedding Gift WormholeThe Procreation CalculationThe Tam TurbulenceThe Planetarium CollisionThe Imitation PerturbationThe Grant Allocation DerivationThe Consummation DeviationThe Citation NegationThe VCR IlluminationThe Paintball ScatteringThe Propagation PropositionThe Confirmation PolarizationThe Meteorite ManifestationThe Donation OscillationThe D & D VortexThe Conference ValuationThe Laureate AccumulationThe Inspiration DeprivationThe Decision ReverberationThe Plagiarism SchismThe Maternal ConclusionThe Change ConstantThe Stockholm Syndrome

The Apartment BuildingApartment 4AApartment 4BThe ElevatorCalifornia Institute of TechnologyWolowitz HouseThe Comic Center of PasadenaPasadenaThe Cheesecake FactoryRaj's ApartmentAmy's ApartmentHoward and Bernadette's ApartmentThe StairsSheldon's Old OfficeRaj's Old OfficeSheldon's New OfficeHoward's LabThe University CafeteriaKripke's Plasma LabInternational Space StationThe Kinetics Lab
See Also
Unaired Pilot

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2010s and beyond