The Big Bang Theory

• 1. The Apartment Across The Hall

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  In the opening scene of the pilot episode, a young woman named Penny moves into an apartment directly across from two physicists sharing a unit in Pasadena. Leonard Hofstadter watches her through his peephole as she struggles to carry boxes up three flights of stairs because the elevator has been broken since he experimented with rocket fuel years ago. Sheldon Cooper stands behind him, analyzing the situation with his characteristic detachment while making notes on a whiteboard filled with equations about string theory and quantum mechanics. The dynamic between these three strangers sets the stage for twelve years of television history. Their initial interactions are defined by awkwardness and social barriers that neither party knows how to cross. Penny dates men who are physically attractive but intellectually incompatible with her new neighbors. She works at a local restaurant called The Cheesecake Factory to pay her way through graduate school in microbiology. Leonard attempts various schemes to win her affection during the first season, often failing spectacularly due to his own social ineptitude. Sheldon's rigid personality creates ongoing conflicts with his roommate over routine aspects of living together. Howard Wolowitz and Raj Koothrappali join them as similarly geeky friends who share interests in science fiction and comic books.

• 2. Romantic Agendas And Breakups

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  Leonard returns from a three-month Arctic expedition in the third season premiere only to find his relationship with Penny strained by premature declarations of love. He tells her he loves her before she can reciprocate the sentiment, leading to their first serious breakup after months of dating. During much of the fourth season, Leonard pursues a relationship with Priya, Raj's sister, creating tension within the friend group and jealousy from Penny. Meanwhile, Amy Farrah Fowler enters the picture as a neurobiologist matched with Sheldon through an online dating site. They communicate daily while insisting to others that they are not romantically involved. In one episode, Amy kisses him on the lips and receives the response "fascinating" instead of annoyance. She later asks him to be her boyfriend, prompting him to draw up a formal Relationship Agreement similar to his Roommate Agreement with Leonard. Their bond evolves slowly from intellectual connection to romantic partnership as Sheldon gradually overcomes his aversion to physical contact. Howard dates Bernadette Rostenkowski, a microbiologist who initially works at The Cheesecake Factory with Penny. Their relationship leads to significant character growth for Howard as he learns to become more mature and less dependent on his mother. They marry during the fifth season finale, coinciding with Howard's departure for a space mission to the International Space Station.

• 3. The Failed Pilot And CBS Deal

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  A different pilot was produced for the 2006-2007 television season but never aired because test audiences reacted negatively to two female lead characters named Katie and Gilda. The original unaired pilot used Thomas Dolby's hit song "She Blinded Me with Science" as its theme music. Creators Chuck Lorre and Bill Prady retooled the show entirely after receiving feedback about the new characters. They brought in Kaley Cuoco to replace Katie and Simon Helberg to play Howard Wolowitz. The second pilot led to a thirteen-episode order by CBS on the 14th of May 2007. Production halted on the 6th of November 2007 due to the Writers Guild of America strike. Nearly three months later, the series returned on the 17th of March 2008, in an earlier time slot. Only seventeen episodes were produced for the first season before the strike ended. The show premiered on the 24th of September 2007, and was picked up for a full twenty-two-episode season on the 19th of October 2007. It received mixed reviews throughout its first season, but reception became more favorable in the second and third seasons. Despite early mixed reviews, seven seasons were ranked within the top ten of the final season ratings.

• 4. Physics Professors And Whiteboards

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  David Saltzberg, a professor of physics and astronomy at the University of California, Los Angeles, checked scripts and provided dialogue, mathematics equations, and diagrams used as props. He served as the science consultant for six seasons and attended every taping. According to co-creator Bill Prady, Sheldon was given an actual equation to be worked on throughout the first season with progress displayed on whiteboards in their apartment. Saltzberg saw early versions of scripts that needed scientific information added to them. He pointed out where writers had made mistakes despite their knowledge of science. He was usually not needed during a taping unless a lot of science or especially the whiteboard was involved. Saltzberg sometimes consulted with Mayim Bialik, who has a Ph.D. in neuroscience, on the subject of biology. Distinguished scientists like Nobel laureate George Smoot appeared as guest stars in the second season. Astrophysicist Neil deGrasse Tyson also appeared in the twelfth season. Cosmologist Stephen Hawking made a short guest appearance in a fifth-season episode and video conferences with Leonard and Sheldon in the eighth season.

• 5. Ratings Records And Syndication Deals

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  The Big Bang Theory started off slowly in ratings, failing to make the top fifty in its first season while ranking sixty-eighth overall. When the third season premiered on the 21st of September 2009, it ranked as CBS's highest-rated show of that evening in the adults eighteen-to-forty-nine demographic. During its fourth season, it became television's highest rated comedy, just barely beating out Two and a Half Men. The sixth season boasted some of the highest-rated episodes for the show so far with twenty million viewers watching "The Bakersfield Expedition." In the age group of eighteen to forty-nine, it was the second highest-rated comedy behind ABC's Modern Family. By the end of the 2012-2013 television season, The Big Bang Theory had dethroned Judge Judy as the ratings leader in all syndicated programming with seven point one points compared to Judy's seven point zero. Warner Bros. Television held the cable syndication rights through TBS which acquired the show's rights in May 2010. The deal set a record price for a cable off-network sitcom purchase. On the 17th of September 2019, HBO Max acquired exclusive American streaming rights to the series.

• 6. Emmy Wins And Critical Standing

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  In August 2009, the sitcom won the best comedy series award from the Television Critics Association while Jim Parsons won individual achievement in comedy. On the 16th of January 2011, Parsons received a Golden Globe for Best Performance by an Actor in a Television Series Comedy or Musical presented by co-star Kaley Cuoco. He was again awarded an Emmy for Best Actor in a Comedy Series on the 18th of September 2011. On the 25th of August 2014, Jim Parsons won another Emmy for Best Actor in a Comedy Series. The show also won the People's Choice Award for Favorite Comedy twice and the International category at the UK's National Television Awards in 2016. Review aggregation website Rotten Tomatoes reports an eighty-one percent approval rating from critics. On Metacritic, the series holds a score of sixty-one out of one hundred based on reviews from twenty-seven critics indicating generally favorable reviews. In 2013, TV Guide ranked the series number fifty-two on its list of the sixty Best Series of All Time. The Big Bang Theory was nominated for the Emmy Award for Outstanding Comedy Series from 2011 to 2014.

• 7. Spin-offs And Franchise Expansion

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  In November 2016, CBS began negotiations to create a spin-off centered on Sheldon as a young boy described as a Malcolm in the Middle-esque single-camera family comedy. Jon Favreau directed and executive produced the pilot which premiered on the 25th of September 2017. Iain Armitage was cast as nine-year-old Sheldon Cooper while Zoe Perry played his mother Mary Cooper. The prequel series came to an end on the 16th of May 2024 with an hour-long episode including George Cooper's funeral. In January 2024, it was announced that there would be a spin-off focused on Georgie Cooper and Mandy McAllister titled Georgie & Mandy's First Marriage. This series premiered on CBS on the 17th of October 2024. On the 12th of April 2023, another spin-off featuring Stuart Bloom was announced in development. Filming for this show began in September 2025 with John Ross Bowie reprising his role as Barry Kripke. A fourth series following Stuart, his girlfriend Denise, and geologist Bert Kibbler is currently in development for HBO Max.