The Big Bang Theory was one of the most watched shows on television, and for good reason. For 12 years, the sitcom has been delighting nerds everywhere, and on May 16, 2019, it had its farewell episode—which had a fair few revelations along the way. In honor of the show's finale, here are some of our favorite Big Bang Theory facts.
If you haven't seen the finale, though, watch out: spoilers!
Big Bang Theory Facts
1. By Any Other Name
The iconic Big Bang Theory theme song is titled "The History of Everything".
2. Right off the Bat
Jim Parsons' audition for the role of Dr. Sheldon Cooper was so perfect that creator Chuck Lorre immediately asked him to come in again. Lorre wanted to be certain that Parsons really was as smart as he appeared. He must have been satisfied: after the second audition, Lorre cast Parsons immediately.
3. Can I Get a Diagnosis, Doc?
Because of Sheldon’s awkward behavior and anti-social qualities, many viewers naturally assume that the character has Asperger's syndrome. However, producer Bill Prady has stated that, "Our feeling is that Sheldon's mother never got a diagnosis, so we don't have one.”
4. Reviewing the File
Jim Parsons, who plays Sheldon, has different ideas about his character's mental profile. Though he respects the producers' decision to keep Sheldon's diagnosis open and unsaid, he has noted that the character does have indicators of the syndrome. Still, he prefers to think of Sheldon as "just another human."
5. Big Bang, Big Checks
In the heyday of The Big Bang Theory, both Parsons (who plays Sheldon) and Kaley Cuoco (who plays Penny) were among the highest-paid actors and actresses in television.
6. We Want More!
CBS knew they had a winner on their hands, and granted Big Bang a massive three-season renewal not once, but twice throughout the sitcom's initial broadcast run. In case you're wondering, that's practically unheard of.
7. Fever Pitch
Instead of writing up a traditional premise and pitching it to CBS, Chuck Lorre and Bill Prady, the co-creaters of The Big Bang Theory, revealed in an interview that they did something a bit different. They actually wrote a full script, hired actors, and “put on a show” for CBS president Les Moonves. It was a risky move, and Lorre later said that he found the experience “crazy.”
Still, it obviously paid off.
8. Can I Get a Second Take?
For all their hard work pitching the project, Lorre and Prady had some trouble getting it off the ground once filming actually started. In fact, they had to film two different pilots; the first one was such a disaster that CBS rejected it. That lost first pilot had a different theme song but still featured Sheldon and Leonard, as well as two female characters.
Additionally, the role of Penny was played by a different actress than Kaley Cuoco, which seems impossible to imagine! Maybe that's why Lorre later said the first pilot "sucked." Regardless, we're glad it all ended up working out. The pilot also had some other differences we'll get into later...
9. Wrong Chuck, Jim
In case you don't know, producer Chuck Lorre is kind of a big deal, and before Big Bang Theory, he worked on hit shows like Two and a Half Men and Dharma & Greg. But if you weren't aware of that, you're not alone: Jim Parsons, who plays Sheldon on the show, was just as oblivious to how powerful Lorre was when he was asked to audition for the pilot.
“I did not know Chuck Lorre at the time,” Parsons told David Letterman in 2014. “I thought he was talking about Chuck Woolery," who is an American game show host. "I thought, why are they so excited about it? We should see what the man has to offer before we’re like, ‘It’s a new Chuck Woolery pilot!'" Apparently, Parsons isn't a fan of game shows.
We're so glad he eventually figured it out!
Sign Up For Our Newsletter
Stories that matter — delivered straight to your inbox.
10. And It All Started With a...
The Big Bang theme song "The History of Everything" is sung by Ed Robertson and backed by his band The Barenaked Ladies. It also has a great backstory. Apparently Lorre and Prady were at a Barenaked Ladies concert when they heard Robertson sing a song about cosmological theory. This was all they needed to know that he was perfect to write and sing their theme song—but Robertson was more suspicious.
Robertson had previously written songs for TV shows and films, but was cruelly rejected for his efforts. Before he took on the project, he needed to get confirmation from Lorre and Prady that he was their number one, and even only, choice. The duo assured him that he was, and he got to writing the song.
11. Not Without My Band Mates
At first, Robertson wrote the theme song as an acoustic ditty, which Lorre and Prady loved. But the singer then insisted that his bandmates accompany him on the track, creating the iconic song we all know today.
12. Bona Fide Credentials
Mayim Bialik, who plays Amy Farrah Fowler, is the only main cast member with an actual PhD: she has a doctorate in neuroscience. “They didn’t have a profession for my character when I came on in the finale of season three,” Bialik once revealed. “In season four, Bill Prady said they’d make her what I am so I could fix things (in the script) if they were wrong."
That's what they call a win-win situation, folks.
13. Casting Call
Wil Wheaton, who plays a “delightfully evil version” of himself on the show, landed his part through Twitter, of all places. One day, he was talking on Twitter about how much he enjoyed the show and laughed at all its jokes. This caught the attention of executive producer Steven Molaro, who then invited Wheaton to a taping. A few days later, he got an emailing asking him if he wanted to actually be on the show.
And the rest, as they say, is history.
14. Keep It Simple
In a 2014 interview, Jim Parsons gave his theory (get it?) about why The Big Bang Theory at its peak reeled in something like 20 million viewers a week, a whopping number that rivals sitcom giants like Friends. As he explained it, "There’s not anything to keep up with...You can enjoy our show without a weekly appointment."
It's clearly a formula that works.
15. Copy Cat
In the middle of the third season of The Big Bang Theory, the producers of the show got wind of a disturbing development: there was a series called The Theorists being broadcast in Belarus that was clearly plagiarized from The Big Bang Theory. It was far more than just a case of inspiration: the characters were near clones, and the scripts seemed to be exact translations.
Producers were afraid to engage in complicated legal action, but then something shocking happened: when the show was revealed to be a rip-off, the actors quit and the show was cancelled. Justice served.
In 2013, Sheldon's phrase "bazinga!" got a whole lot more iconic. This was the year a group of biologists discovered a new species of orchid bee and named it Euglossa bazinga. Producer Steven Molaro was incredibly flattered at the choice, and jokingly added, "bees are [Sheldon's] third-favorite flying creature."
17. Blossoming Into Her Own
The show is full of inside jokes and easter eggs for devoted fans—and this even extends to Miyam Bialik's casting. In an early episode, Raj, Leonard, and Howard are trying to find a teammate for their Physics Bowl Team. Raj suggests veteran actress Bialik, saying, "You know who's apparently very smart, is the girl who played TV's Blossom. She got a PhD in neuroscience or something."
Though Leonard shoots the suggestion down, the show proved him wrong years later when Bialik actually joined the sitcom in Season 3, playing Dr. Amy Farrah Fowler.
18. Friends in High Places
Throughout its 12-year run, the show has featured science (and science fiction) heavyweights like Leonard Nimoy and Stephen Hawking, but producers also joked about one of their ideal guests: the pope. "We've done some episodes about religion and science, and we thought Pope Francis might be good," Bill Prady once said. "He's probably too busy now."
19. Seeing Double
The second, third, and fourth floor of Sheldon and Leonard's apartment building are actually just the same set, re-dressed for different scenes. Don’t believe us? Check out the scuff marks on the molding, which are identical on each level as they walk up the stairs.
20. Crossover Episode
Like any good sitcom worth its salt, Big Bang Theory has some crossover actors. Sara Gilbert plays a former girlfriend of Leonard's, and she also played Johnny Galecki's girlfriend in Roseanne. But that's not all: Laurie Metcalf, who plays Sheldon's mother, also starred with him in Roseanne.
21. Time to Change Your Clothes
The male characters each have one item or category of clothing that is worn in pretty much every episode. For Sheldon, it's T-shirts over long-sleeved shirts. Leonard always wears a hoodie over a T-shirt along with a jacket, and Raj favors sweater-vests. Finally Howard usually wears a dickie along with some kind of outerwear.
Howard also likes wearing large belt buckles, but it's pretty hard to miss those.
22. Tight Fit
Howard also has a penchant for wearing very skinny jeans with those big belt buckles. As actor Simon Helberg joked, "I've learned the smallest pants size I can squeeze into!"
23. Do Re Mi
Actress Melissa Rauch, who plays Bernadette on the show, originally played the character with a much lower and more normal voice. But as the character took shape under her acting, Bernadette's voice started to rise to the quirky high pitch we know and love today. Rauch also says she had a direct inspiration for the change: her mother's voice, though "without the Jersey."
24. Soft Kitty, Warm Kitty
Sheldon's "Soft Kitty" healing ritual is yet another memorable moment from the show, but the writers and producers struggled to find the right tune when searching for a suitable song to use. After much struggling, producer Bill Prady finally landed on what he wanted—and the inspiration came quite close to his home.
"It's from my daughter's preschool in Sherman Oaks," Prady revealed. "It was from Australia, and one of the teachers heard it there."
25. These Are a Few of My Favorite Scenes
When he visited the set of Inside the Actor's Studio, actor Jim Parsons told the crowd what his three favorite scenes in the show were: when Penny gives Sheldon a napkin that was signed and used by Leonard Nimoy; when Sheldon gives Amy his relationship agreement, and finally, when Sheldon first tries a Long Island Iced Tea.
Good choices, Jim!
26. Girl Power
Howard loves his female superheroes, and the figurines in his room (as well as in his house with Bernadette), are all of women. Sure, there's also a Jabba the Hutt, but Princess Leia is right in front of him, so it hardly counts. Later on in the show, we even get a little figurine of Bernadette after Howard and Raj try out a 3-D printer.
We're sure Bernadette was happy with that.
Leonard's last name is "Hofstadter," and this gives a nod to no less than two famous scientists. The first is Robert Hofstadter, who won the 1961 Nobel Laureate in Physics. The second is Robert's own son Douglas Hofstadter, who works with consciousness and cognition. The younger Hofstadter won a Pulitzer Prize in 1980 for his book Gödel, Escher, Bach: an Eternal Golden Braid.
Not bad namesakes, if you ask me.
28. Show offs
Though Howard's mom is always just off screen, Raj's parents are conversely very visually present throughout the show. Though they live in India, Raj is always Skyping them.
29. Brotherly Love
In the early episodes of the show, Sheldon mentioned having an elder brother in addition to his twin sister, Missy. He claims that his brother bullied him, and their relationship doesn't seem to be too healthy. However, although Missy appeared on the show in earlier seasons, it took a while for Sheldon's long lost brother to finally appear.
In season 11, Sheldon's brother is finally revealed to be Georgie Cooper, as played by Jerry O'Connell. Georgie works in a tire store and is called "Dr. Tire," a name that rankles the real Dr. Sheldon.
30. Hunger Pangs
Though there are frequently scenes in the cafeteria, most of the time the characters of The Big Bang Theory don't actually eat. The actors either pretend to chew food, or more often they just push their food around on their plates. It's too difficult otherwise to get a good, consistent shot of the dialogue the characters are speaking.
Bet this makes for some long days on set!
31. First and Fated
Get a load of this: the first person to speak to each of the main female characters in the show is their future partner. In other words, Leonard is the first person to talk to Penny, Howard is the first person to greet Bernadette, and Sheldon, of course, is the first person to speak to Amy. No matter the season the women were introduced in, this remains the same.
32. Talented Family
Kaley Cuoco has a sister named Briana who is just as talented as Kaley. You might remember that the Big Bang cast and crew have participated in flash mobs in the past, most memorably in a dance to "Call Me Maybe." Well, Briana actually helped choreograph that dance. She's also appeared on the show in a minor role.
33. Child Prodigy
Though the show has come to an end, there's still lots more in store for fans of Big Bang Theory. In 2017, the prequel show Young Sheldon, which follows Sheldon through his various foibles as a brilliant child, began airing on CBS. It was actually actor Jim Parsons himself who suggested the idea for the series to studio executives.
As of 2019, the show has been renewed for up to four seasons. Keep that Sheldon goodness coming!
34. Origin Story
The phrase "Bazinga!" may very well have turned Big Bang from a successful show to a wildly popular one, and it has some interesting origins. Writer Stephen Engel used to say the term whenever he decided to play a prank on one of his colleagues, and he once got Bill Prady with it. He gave Prady what he thought was a juicy grapefruit, but it had actually been hollowed out and stuck back together.
When Prady realized the gag, Engel customarily yelled "Bazinga!" And thus, a catch phrase was born.
35. Improv Acting
Still, "Bazinga!" wasn't even in the original script when it first appeared. Parsons remembers it being added in just before filming as a kind of ad-lib.
36. Not the First of Its Name
Though Big Bang did a lot to popularize it, the show didn't coin the term "Bazinga." Variations of it (like "Zing!" or "Bazing!") have appeared throughout history, in both real life and on film. Perhaps the first on-screen use of "Bazinga" itself was all the way back in an episode of the classic series The X-Files in 2000.
To me, it will always be Sheldon's.
37. Turtle Power
In one mid-series episode, Sheldon says that his favorite cartoon theme song is the one from Teenage Mutant Ninja Turtles. The writers may have been sucking up to the boss a bit with this creative choice: the anthem was actually written by showrunner Chuck Lorre.
38. Funny and Smart
It won't surprise you to know that The Big Bang Theory kept a physicist on retainer to make sure their plot points and conversations made scientific sense. But it might surprise you to know that their hired physics expert, David Saltzberg, had a sense of humor. In fact, he even wrote one of the jokes for the hit sitcom.
In the episode in question, Sheldon is fighting with another scientist. When Penny tries to get Sheldon to talk about the "little misunderstanding," he replies, “A little misunderstanding? Galileo and the Pope had a little misunderstanding!” That joke is all Saltzberg.
39. Heartbreaking Tribute
Throughout the show, we often hear Howard's mom yelling at him from another room. This voice is done by actress Carol Ann Susi, but she tragically died of cancer while the show was in the middle of its run. With her death, the character also died on the show. Heartbroken over their loss, The Big Bang Theory made sure to incorporate a touching tribute to the actress.
In later episodes, a small picture of Susi is visible on the side of Sheldon and Leonard's fridge. The picture is tiny and unrecognizable, but in the behind-the-scenes DVD feature, they reveal that it’s her.
40. Faceless Woman
We do get one glimpse of Howard's mom, played by Carol Ann Susi, throughout the series: we see her very quickly in the season five finale, though we still don't see her face.
41. Return of the Bazinga
Young Sheldon has given fans lush backstories to many of the beloved jokes and plot points on The Big Bang Theory. For example, later seasons of Big Bang rarely (if ever) used its most famous saying, "Bazinga!" Yet Young Sheldon has provided a rather heartbreaking origin for the phrase, which Sheldon often used to indicate when he was telling a joke.
In the episode, the child Sheldon, worried that he's becoming humorless and maladjusted, goes to a shop and gets a practical joke kit to use on his friends and family. The name of the company that makes that kit? Bazinga.
42. Sheldon: Rated R
Sheldon's awkward, asexual tendencies are known and loved by Big Bang viewers, but he was originally quite a different character in the failed first pilot. When the writers initially created him, Sheldon actually had a pretty big libido and bedroom appetite, and he even admits in that first episode to owning more than a few adult magazines at home.
This version of Sheldon also likes women with big butts, and is revealed to have once had intercourse with a woman at a Star Trek convention. I don't know about you, but I'm scandalized.
43. Leonard & Penny Forever
In many ways, Penny and Leonard are the romantic pairing to end all romantic pairings. That chemistry must have been undeniable, too, because Kaley Cuoco once revealed that she had secretly dated Johnny Galecki, who plays Leonard. The pair dated for two years while the show was still running, and at the same time that their characters were dating.
Sadly, they split in late 2009. Nonetheless, Cuoco says they are still friends.
44. Pregnant Pause
The finale of the series provided many heartwarming moments for longtime fans, and tied up a lot of the series' loose ends. The episode largely revolves around Sheldon and Amy trying for and winning the Nobel Prize, which is an incredibly fitting end for the power couple. However, there was one controversial moment that absolutely enraged some fans.
During the episode, it's revealed that Penny is happily pregnant with Leonard's child. Many viewers noted that Penny has often said she didn't want children, and these fans criticized the show for both erasing this part of her character and suggesting that she and Leonard could only be happy if they had children together.
Whatever the final judgment on this episode is, it's still sad to see The Big Bang Theory go. Goodbye, old friend.