Sheldon needs half a billion dollars to prove his latest concept of string theory, which the University cannot afford to fund. Crowdfunding and selling some of his most valuable comic books to Stuart give him a small start. When Raj mentions gambling in Las Vegas, Sheldon goes there but is caught calculating odds by security before he can make any bets. Meanwhile, Amy takes Penny and Bernadette shopping for her wedding dress. She loves an old-fashioned one that the other girls admit that they find ugly, though Penny assures Amy she can make her own decisions about her wedding. Sheldon, however, comes home and sees Amy in the dress and loves how she looks.
"The Plagiarism Schism" -- Pictured: Howard Wolowitz (Simon Helberg) and Bernadette (Melissa Rauch). Kripke (John Ross Bowie) has proof that Dr. Pemberton (Sean Astin) plagiarized his thesis in college, and Sheldon and Amy aren\'t sure if they should turn him in or not. Also, Wolowitz is happily surprised to learn that Bernadette wasn\'t the only waitress at the Cheesecake Factory who had a crush on him back in the day, on THE BIG BANG THEORY, Thursday, May 2 (8:00-8:31 PM, ET/PT) on the CBS Television Network. Photo: Michael Yarish/Warner Bros. Entertainment Inc. © 2019 WBEI. All rights reserved. (Photo: Michael Yarish, Warner Bros.)

After the strike ended, the show was picked up for a second season, airing in the 2008–2009 season, premiering in the same time slot on September 22, 2008.[17] With increasing ratings, the show received a two-year renewal through the 2010–11 season in 2009.[18][19] In 2011, the show was picked up for three more seasons.[20] In March 2014, the show was renewed again for three more years through the 2016–17 season. This marked the second time the series gained a three-year renewal.[21] In March 2017, the series was renewed for two additional seasons, bringing its total to 12, and running through the 2018–19 television season.[22]


'The Big Bang Theory' executive producers Chuck Lorre, left, and Steve Hollland and stars Kevin Sussman, Mayim Bialik, Jim Parsons, Kaley Cuoco and Kunal Nayyar stand to the left of 'The Big Bang Theory' stage plaque, with executive producer Bill Prady, star Melissa Rauch, executive producer Steven Molaro and star Johnny Galecki, director Mark Cendrowski and star Simon Helberg on the right. (Photo: Warner Bros.)
Penny and Bernadette attend a pharmaceuticals conference, where Bernadette's business rival Danny tries to recruit Penny. Bernadette is offended that Penny is considering the offer. At the meeting with Danny, Bernadette steps in to say Penny is the best saleswoman she knows and Penny agrees to keep working for Bernadette. Meanwhile, the rest of the gang does simple behavioral experiments on the Wolowitz children using a book Sheldon found. Leonard is shocked that his childhood was filled with these experiments; although his mother remembers that time with him fondly, she admits the experiment with him is not over. Raj figures Amy planted the book to get Sheldon to like babies, though Sheldon later states he would be open to having kids.
By season seven, Galecki, Parsons, and Cuoco were also receiving 0.25% of the series' back-end money. Before production began on the eighth season, the three plus Helberg and Nayyar, looked to renegotiate new contracts, with Galecki, Parsons, and Cuoco seeking around $1 million per episode, as well as more back-end money.[36] Contracts were signed in 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.[37] Helberg and Nayyar were also able to renegotiate 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 eight.[38] By season 10, Helberg and Nayyar reached the $1 million per episode parity with Parsons, Galecki, and Cuoco, due to a clause in their deals signed in 2014.[39] 

After learning Sheldon went behind their backs to work with the military again, Leonard and Howard say Sheldon is like Thomas Edison, taking credit for others' ideas, while they are more like Nikola Tesla. Leonard and Howard bring in Barry Kripke to help create a better idea than Sheldon's, but Kripke goes to the military himself, cutting all three of them out. Meanwhile, Bernadette fears Ruchi is trying to steal her projects at work while she is on maternity leave and enlists Raj to spy on her. Though he finds proof that Ruchi may be stealing from Bernadette, Raj tries to defend Ruchi like a boyfriend would, pointing out Bernadette's hypocrisy as she would most likely have stolen from other people's projects as well. Ruchi is not happy about this and promptly dumps Raj.
In the third-season finale, Raj and Howard sign Sheldon up for online dating to find a woman compatible with Sheldon and discover neurobiologist Amy Farrah Fowler. Like him, she has a history of social ineptitude and participates in online dating only to fulfill an agreement with her mother. This spawns a storyline in which Sheldon and Amy communicate daily while insisting to Leonard and Penny that they are not romantically involved. In "The Agreement Dissection", Sheldon and Amy talk in her apartment after a night of dancing and she kisses him on the lips. Instead of getting annoyed, Sheldon says "fascinating" and later asks Amy to be his girlfriend in "The Flaming Spittoon Acquisition". The same night 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 had a lawyer read through it.
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.[70] When Leonard joins Sheldon, Raj, and Howard on a three-month Arctic research trip, it separates Leonard and Penny at a time when 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.[71] Sheldon and Amy also briefly end their relationship after an argument over which of their fields is superior.[72]
Initial reception for the series was mixed. The review aggregation website Rotten Tomatoes reported a 52% approval rating for the first season based on reviews from 23 critics, with an average rating of 5.18/10. The website's critical consensus reads, "The Big Bang Theory brings a new class of character to mainstream television, but much of the comedy feels formulaic and stiff."[91] On Metacritic, the season holds a score of 57 out of 100, based on reviews from 23 critics, indicating "mixed or average reviews".[92] Later seasons received more acclaim and in 2013, TV Guide ranked the series #52 on its list of the 60 Best Series of All Time.[93]
^ Jump up to: a b Kondolojy, Amanda (October 12, 2014). "'Gotham' Has Biggest Adults 18–49 Ratings Increase; 'Gotham' & 'Red Band Society' Top Percentage Gains & 'How To Get Away With Murder' Tops Viewer Gains in Live +7 Ratings for Week Ending September 28". TV by the Numbers. Archived from the original on October 16, 2014. Retrieved October 13, 2014.
Kaley Cuoco's life after The Big Bang Theory is going to be animated. Cuoco has signed on to voice and executive produce DC Universe's new Harley Quinn series. She'll play the titular character in the new streaming series targeted toward mature audiences. In 2017, she got the rights to The Flight Attendant, a miniseries based on the book of the same name, which she was poised to star in. The Flight Attendant follows Cassandra Bowden, a flight attendant, who wakes up, hungover, in her hotel room with a dead body next to her. She goes about her day and heads back to New York. is she the killer? That's what she wonders. "This is the first time I have a project that I'm kind of nurturing from the beginning, so it's been a really interesting experience," she told PopSugar in March. "It's got a lot of aspects. It's very sexy. It's a really well-written book, which is why I wanted to option it. I'm ready to bring the character to life."

After learning Sheldon went behind their backs to work with the military again, Leonard and Howard say Sheldon is like Thomas Edison, taking credit for others' ideas, while they are more like Nikola Tesla. Leonard and Howard bring in Barry Kripke to help create a better idea than Sheldon's, but Kripke goes to the military himself, cutting all three of them out. Meanwhile, Bernadette fears Ruchi is trying to steal her projects at work while she is on maternity leave and enlists Raj to spy on her. Though he finds proof that Ruchi may be stealing from Bernadette, Raj tries to defend Ruchi like a boyfriend would, pointing out Bernadette's hypocrisy as she would most likely have stolen from other people's projects as well. Ruchi is not happy about this and promptly dumps Raj.
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,[97] 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,[98][99] and was third in total viewers, trailing NCIS and Sunday Night Football.[100] 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.[101][102]
^ "Editor's Note: With final Monday ratings in, The Big Bang Theory has now reached a new series high in viewers (16.32m) and was the night's top program in adults 18-49 (5.9/15), up a tenth from this morning. -- "Two and a Half Men" Soars to Its Best Adult 18-49 Rating in Three Years". CBS. March 9, 2010. Archived from the original on January 8, 2014. Retrieved January 5, 2013.
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