Two nerdy physicists share an apartment and an unlikely friendship with their beautiful neighbor with whom one of them is infatuated. Like the universe after the big bang, the show's popularity expanded, thanks to breakout star Jim Parsons, along with the chemistry among the friends and the developing romance between Leonard and Penny. The addition of Melissa Rauch and Mayim Bialik in later seasons also enhanced the stories and relationships of the leads.
When Penny tells Leonard he needs to be more assertive in making decisions for himself, he starts standing up to Sheldon over small things. His confidence makes him want to demand the university support his idea for a plasma physics project. He threatens to quit if the university refuses, alarming both Sheldon and Penny, who consider this to be a risky career move. Sheldon is conflicted on whether or not he is being selfish over Leonard's decision, but Amy suggests that the fact that he is worried over Leonard's motivation proves that he does care about him, which he acknowledges. President Seibert refuses the project, but in order not to lose Leonard, gives him co-leadership over a photon entanglement project, leaving Leonard proud of himself and Penny impressed. Meanwhile, Raj shows Anu his lab, and suggests one possible answer for something he's seen in space might be alien life. When someone mentions this at his observatory presentation, the scientific community starts mocking him as a conspiracy theorist. Raj points out scientists should consider all possibilities when seeking the truth, though this causes people to think he believes in the Loch Ness Monster.
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 series 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.
After the birth of Michael, Howard and Bernadette are unsure who should stay home with the kids. Howard decides to look after the kids one day to show he has what it takes to care for them. While Bernadette falls back in love with her job on a trip to the office, Howard is quickly tired and realizes he might not have what it takes to be a stay-at-home dad. Howard and Bernadette realize neither them is ready to give up their job.
In March 2017, the main cast members (Galecki, Parsons, Cuoco, Helberg, and Nayyar) took a 10% pay cut to allow Bialik and Rauch an increase in their earnings. This put Galecki, Parsons, Cuoco, Helberg and Nayyar at $900,000 per episode, with Parsons, Galecki, and Helberg also receiving overall deals with Warner Bros. Television. By the end of April, Bialik and Rauch had signed deals to earn $500,000 per episode, each, with the deals also including a separate development component for both actors. The deal was an increase from the $175,000 – $200,000 the duo had been making per episode.
Raj hooks up with a recently separated woman, Nell, after one of his lectures at the planetarium. Her husband, Oliver, confronts Raj at the planetarium and then breaks down over the end of his marriage. After comforting Oliver, Raj talks to Nell and convinces her to give her husband another chance. Meanwhile, after diving once again into string theory and sprawling his work across his and Amy's apartment, Sheldon approaches a reluctant Leonard and Penny and convinces them to let him use his old room to study for a three-day trial period with an agreement to be quiet and stay out of their way. Sheldon surprisingly sticks to this agreement, being a reasonably good guest, which shockingly frustrates Leonard to no end. After Leonard lets out his frustrations, Sheldon then renegotiates the guest tenancy agreement for an extra few days and resumes being his normal demanding self, much to Leonard's relief.
The Big Bang Theory started off slowly in the ratings, failing to make the top 50 in its first season (ranking 68th), and ranking 40th in its second season. When the third season premiered on September 21, 2009, however, 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.
Producers, writers and others, including recurring guest star Wil Wheaton, joined the festivities on set and — hardly a spoiler alert — more laughing, crying and hugging ensued. Lorre embraced a happy Parsons, then moved on to each cast member as if it were a reception line. Galecki shared long, emotional hugs with his colleagues. After trying to keep their emotions under control for so long, it was finally time to just let go.
“The Big Bang Theory” premiered on Sept. 24, 2007, and for most of its run, was primetime’s most-watched comedy series. It remains one of the most successful sitcoms in TV history — and the longest-running multi-cam comedy of all time (recently surpassing “Cheers”). It has generated an estimated $1 billion and counting in syndication. The show has received 52 Emmy Award nominations and 10 wins, seven Golden Globe nominations, and the spinoff prequel, “Young Sheldon.”
When Mayim Bialik first learned she had to say goodbye to neurobiologist Amy Farrah Fowler, she opened up about the show ending in a blog post, asking, "And now I start to figure out what next. Where will life take me? Where will this career go? What do I want?" Up next she has a voice role in The Inspector Chronicles, a quasi-parody of Doctor Who making the leap from short to feature film. She'll reprise her role as the voice of the Inspector's time machine, known as B.O.O.T.H. Aside from that, she doesn't have any major projects lined up, aside from preparing to not see her close-knit cast the way she'd grown accustomed to. "We'll have to see what our lives look like," she told Us Weekly in early May about the chance they'll remain close. "I mean, we're all going to be on different schedules now; it's very different."