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]
Sheldon and Amy are surprised to find that Wil Wheaton's new Professor Proton show is actually very entertaining and that Wil had Howard on as a guest. On Howard's suggestion, Sheldon apologizes to Wil, mending their friendship, and tells him he wants to be on the show; but Wil asks for Amy. Sheldon tells her to do it, but she says she often doesn't do things to avoid upsetting him. Sheldon is horrified when he realises how selfish he has been, especially when he finds out that the men do the same for him. Sheldon encourages Amy to go on the show to inspire girls to pursue science while trying to control his obvious jealousy for her. Meanwhile, Leonard writes a book about a physicist that solves a murder, the protagonist Logan Dean is based on himself. Bernadette points out Logan's mean boss Illsa is similar to Penny, who thinks it is based on Bernadette, though Leonard does not correct her. However, Bernadette tells Penny the truth, upsetting her and making her mad at Leonard. After calling his mother for advice, Leonard learns that Illsa is actually like her; but abandons the book when he realizes he wrote romantic tension into the relationship between the characters.
On March 13, 2017, CBS ordered the spin-off Young Sheldon series. Jon Favreau directed and executive produced the pilot. Created by Lorre and Molaro, the series follows 9-year-old Sheldon Cooper as he attends high school in East Texas. Alongside Armitage as 9-year-old Sheldon Cooper and Perry as Mary Cooper, Lance Barber stars as George Cooper, Sheldon's father; Raegan Revord stars as Missy Cooper, Sheldon's twin sister; and Montana Jordan as George Cooper Jr., Sheldon's older brother. Jim Parsons reprises his role as adult Sheldon Cooper, as narrator for the series. Parsons, Lorre, Molaro and Todd Spiewak will also serve as executive producers on the series, for Chuck Lorre Productions, Inc. in association with Warner Bros. Television.[214] The show's pilot episode premiered on September 25, 2017. Subsequent weekly episodes began airing on November 2, 2017 following the broadcast of the 237th episode of The Big Bang Theory.[215]
^ "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.
While Jim Parsons was the one who'd had enough with The Big Bang Theory, opting not to renew his contract to play socially awkward theoretical physicist Sheldon Cooper and bringing about the demise of the show in the process, he won't be escaping the show's orbit entirely. He's still attached as both executive producer and narrator of prequel series Young Sheldon, returning for a third season on CBS this fall. "There was no factor; there was no situation that I was like, 'Well, I've had enough of that.' No. There was nothing like that. It was just…when you know, you know," he explained to The Hollywood Reporter in mid-May. 
Howard dresses as Sheldon for Halloween at work, hurting Sheldon's feelings. When Howard does not apologize, Amy and Sheldon dress as Bernadette and Howard at Penny and Leonard's party, angering Bernadette. Sheldon and Bernadette later bond over their painful childhood memories. Leonard is upset that Penny does not seem to remember that their first kiss was on Halloween. Penny later admits she does remember, but does not like to think of their first kiss as an unromantic drunken hookup. She likes to imagine their first kiss was one they shared on Leonard's birthday, which pleases him.

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 former local sister station in Atlanta also holds local weeknight rights to the series).[157] 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".[158] CTV holds national broadcast syndication rights in Canada, while sister cable network The Comedy Network holds cable rights.

In 2010, Leonard, Howard, and Raj mined a lot of Bitcoin, now worth thousands of dollars, but left Sheldon out due to his fear of tax implications. Flashbacks are shown of how the Bitcoin ended up on an old laptop of Leonard's, which Penny gave to her old boyfriend Zack after she and Leonard broke up. In 2017, Leonard and Penny retrieve the computer from Zack, who first shows them a video of a drunken Penny apologizing for breaking up with Leonard. The Bitcoin is not found on the laptop. Sheldon had moved it to a flash drive on Leonard's keychain to teach the guys a lesson, but Leonard lost the keychain years ago. A final flashback to 2013 shows Stuart discovering the flash drive, which he decides to erase and sell for $10.

Howard and Bernadette's new neighbor Andy begins using floodlights mounted on his balcony that encroaches on their rear deck and hot tub. Investigating whether the lights comply with city code, they enlist Sheldon to help them with the paperwork, but Sheldon finds out Howard and Bernadette's own deck is also not code-compliant. He considers turning them in, but ultimately chooses friendship over the rules. He does report Andy though for violating property lines, allowing Howard and Bernadette to enjoy their deck again. Meanwhile, Bert wants to cut into a meteorite with Raj's help, rejecting Leonard's idea to use his laser to do so. Leonard dreams that he opens the meteorite with his laser, becomes possessed by an alien intelligence and eats Bert, Raj and Penny. He later apologizes to Raj and Bert, admitting he was jealous. The possibility of the meteorite unleashing a plague scares Stuart and Denise, who use it as foreplay for procreation, Stuart closing the store on Sheldon when he tries to browse.
Simon Helberg doesn't have any projects listed in development as of now, but he has had a burgeoning movie career. He was nominated for a Golden Globe for Florence Foster Jenkins and also appeared in Paint It Black. Maybe he's holding out hope for a spinoff for his Howard Wolowitz? When THR asked creator Chuck Lorre if he was gestating on ideas for any Big Bang character spinoffs, he coyly responded, "You can't help but gestate a little..."

Professor Proton, Sheldon's favorite childhood show, is being rebooted. After unsuccessfully auditioning for the part, he goes to Wil Wheaton for acting tips for his second audition. However, Sheldon is later dismayed when Wil is offered the role instead. Talking it over with Arthur in his dreams, he is still upset to see his idol replaced and considers Wil an enemy again. Meanwhile, Howard gets a vasectomy while Bernadette is on bed rest. Penny offers to take care of Halley for them, but they insult her by expecting her to be irresponsible. Halley ends up saying her first word by calling Penny "Mama."


Sheldon is annoyed that Amy does not have time to work on the super-asymmetry project with him so he talks President Siebert into getting her removed from her own project at the university. Amy is angry at both of them as she wants to still have her own identity outside the marriage. When confronted by Amy, Siebert apologizes to her but states that it will be difficult for the university to give her her project back. After talking with Arthur Jeffries in a dream, Sheldon apologizes to Amy and both of them talk about their fears in their marriage. Meanwhile, Raj does not want to have Howard join him in his show at the planetarium, thinking he'd just use his astronaut status to make it about himself. Raj eventually lets him join in and Raj and Howard spend the whole time complimenting each other, surprising Bernadette, Leonard and Penny.

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."
^ "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.
The first and second seasons were only available on DVD at their time of release in 2008[197] and 2009.[198] Starting with the release of the third season in 2010[199] and continuing every year with every new season, a Blu-ray disc set has also been released in conjunction with the DVD. In 2012, Warner Bros. released the first two seasons on Blu-ray,[200] marking the first time that all episodes were available on the Blu-ray disc format.
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.[103] 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.[104] The Big Bang Theory did not place first in syndication ratings for the 2013–14 television season, beaten out by Judge Judy.[105]
Sheldon is still despondent over the disproving of his and Amy's theory on asymmetry. Leonard brings out a VHS tape of a pep talk that Sheldon recorded as a boy, but it turns out that his father had recorded a long-ago football game over it. Sheldon, however, is buoyed by a halftime pep talk his father gave the team, realizing he and his father had more in common than he previously thought. This causes Amy to view asymmetry and symmetry in another manner and they decide their theory may not be dead after all. Bernadette finds an old tape of Howard preparing to audition for The Magic Castle. She insists he fulfill his dream and audition with her as a coach, drawing on her beauty pageant experience. Howard eventually decides to audition his own way, and promptly botches his chances by accidentally destroying a judge's Rolex.
When Leonard receives a braggy Christmas letter from his brother, he feels bad about how little he and Penny have achieved in the past year. Leonard wonders if he and Penny should be thinking about the next step after two years of marriage, like buying a house or having a baby. Penny tells him she wants to do all those things someday, but she has a bunch of stuff she would like to do first.
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