The hit CBS sitcom The Big Bang Theory ended after 12 seasons and 279 episodes, though it could have continued another year if star Jim Parsons had agreed. The show's hour-long finale drew 18 million viewers to say goodbye to quirky scientists and friends Sheldon, Leonard, Howard, and Raj, along with Penny and Amy.

While wrapping, unresolved questions remained. The show promoted nerd culture and intelligence. Though over, its impact and fandom persist. After 12 years together, the cast became family; for fans worldwide, the characters were as well. 

20 Will Raj Ever Find Love Beyond Cinnamon?

It's disappointing that one of the most romantic leads on the show didn't find romance. You could easily argue that the character who completed the most personal growth during the entirety of The Big Bang is Raj. He went from a spoiled adult, living off mom and dad, and couldn't even talk to girls, to someone who knows himself well enough to walk away when a relationship doesn't feel just right.

19 How Will Penny Cope With Being A Mom When She Didn't Even Want Kids?

A lot of people were annoyed that Big Bang spent a good deal of the last season of the show demonstrating conflict between Leonard and Penny and her wanting to remain child free. In the last episode Penny revealed she was expecting and was good with it. This unexplained 180 didn't sit well with a lot of people.

18 Will Bernadette & Howard Finally Call It Quits?

Most people probably don't want their relationship judged for romance during the years when they have very small children, but these two have seemed especially unhappy over the years. Not that this has ever been addressed in the show. Something about the balance of power in the relationship, like how Bernadette obviously believes she's settled, yet Howard gets to do whatever he wants, isn't sustainable.

17 Does Penny Have A Last Name Or Is She Like Cher?

Odds are if you're a die-hard fan or have watched a few seasons of the show on and off you know the last names of many of the characters. Guess what? Penny's last name is never revealed through the course of the show. Actor Kaley Cuoco says that she has an idea in her head of what she thinks Penny's last name should be but enjoys this little secret about her character.

16 Could Stewart Become Successful?

Stewart slowly got his life together over the course of the show. When the series ended, he had moved in with his girlfriend Denise, who also works at his store. Hopefully these two can work together to create a successful business model that will allow him to win at love and a career.

15 Will Sheldon Keep On Growing?

Since the growth happened over 12 seasons the big changes in Sheldon Cooper may not be as noticeable to some. Go back and check him out in season one to see if you feel any differently. The impact of his friends, family, and partner Amy have changed him into a virtually different, better person over the years.

14 Will There Be Any Spin Off Series?

We were introduced to Young Sheldon for a couple of seasons before The Big Bang Theory called it quits, but would another spinoff work? Which characters would you focus on? Frasier aside, very few other shows get spinoffs that are nearly as successful as the original show, but with the quirky characters on Big Bang, they may have a shot.

13 Are Sheldon & Amy Going To Start A Family?

Sheldon and Amy (or Shamy, if you will) have already practiced pseudo-parenting techniques on their friends in the form of an experiment, but will they have kids? The unpredictability of children would not be welcomed by either potential parent, but man they would make some really smart kids. I smell a spinoff in a decade or so, how about you?

12 Who Is Howard's Father?

Howard was proudly raised by his single mom. When he finds an old letter from his dear old dad, it was an emotional episode which caused many to wonder, who is his dad? While Howard chose to not actively look for his dad, maybe one day dad will eventually cross his path. Perhaps dear old dad will want to meet his grandchildren.

11 What's Next For Amy's & Sheldon's Career?

Was the Nobel Prize the success swan song for Sheldon and Amy or are they going to go on and do more? After reaching this professional milestone there is very little that either could do to compare. Perhaps they will focus their efforts on other things – Flags with Friends, Amy becoming a professional harpist? The sky is the limit for this duo.

10 How Long Will The Elevator Work & How Will It Break?

On the last episode of the show we saw the elevator in working order for the very first time (aside from flashbacks from when it was broken). With so many shenanigans you have to ask what it will take for the Big Bang gang to destroy the elevator once more, even if it's done on purpose for old times sake.

9 Does Leonard Actually Have Siblings?

Throughout the show we meet Leonard's mom routinely as she shames him about being her least successful child. Through this we learn that he has two other siblings, a sister without a name who is a scientist working to cure diabetes and a brother named Michael who is a tenured law professor at Harvard. Since we never meet them, perhaps they were actors hired by his mom for another one of her psychological analyses of Leonard. We'll never know.

8 What Are Bernadette's & Howard's Kids Really Like?

In Big Bang Theory the old expression, 'children are best seen and not heard' is flipped on its head since routinely we only hear the babies cry (complete with pipes that match those of Howard's late mother). It isn't until an episode in the final season that we see the children for the very first time. What other pieces of Howard's and Bernadette's lives do we know nothing about?

7 Will Any Of These Successful Professionals Buy A Home?

Real estate is expensive in California, so it's understandable why these friends were renting well into their thirties. But absolutely everyone in the show has a good to great job with an excellent salary and benefits by the end of the series. You'd think at least some of them would pool their money together and stop renting.

6 Will Howard Attempt to Get His PhD?

Howard only having a master's degree as an engineer is often the butt of Sheldon's jokes. Although he's a very successful engineer and even went to space, we also know that he's competitive. His attempting a doctorate came up a few seasons back, but it never went anywhere. Maybe when his kids are older, Howard will get his PhD, even if it's only to rub it in Sheldon's face.

5 What Does Penny Really Want?

Penny wanted to be an actor, but that didn't work out. Soon she discovered she was good at pharmaceutical sales but didn't really have a passion for it. Sure, she's making more than Leonard by the time the series is over, but that doesn't mean she's happy. Penny seems to have sacrificed more than other characters in the show, which makes it hard to know whether she'll really be happy for the long haul.

4 What Ever Happened To Howard's Half Brother?

In 2015, Howard's younger half-brother shows up on his doorstep. Played by Matt Bennett the character certainly throws Howard a curve ball. That one episode aside, there is minimal impact on Howard's life, that audiences get to see. Do the two form a close relationship? Guessing by the character vanishing, probably not.

3 How Will Amy Continue To Inspire Young Female Scientists?

Amy (and Mayim Bialik) both serve as inspirations for young women in academics and science. After winning the Nobel Prize, perhaps Amy could start a mentorship program or give TED talks. It's nice to see someone so aware of the impact they have on their profession, even if the final show means they determine they need a makeover to look more conventionally beautiful. One step forward, two steps back, sigh.

2 Will Anyone Make Cameos In Young Sheldon?

You'd need a time machine or an elaborate dream sequence to have characters from The Big Bang Theory show up on Young Sheldon, but that doesn't leave it out of the realm of possibility. Perhaps the actors will come in and play other characters completely unrelated to their time on Big Bang, just for a lark.

1 Are We Going To Talk About Sheldon's 'Diagnosis'?

Although it's an ongoing joke when Sheldon says, "I'm not insane, my mother had me tested", some of the more clinical things about Sheldon's unique way are never addressed on the show. Jim Parsons has said that he played Sheldon like he is on the autism spectrum, which has caused some controversy, since a diagnosis and the social responsibility is never addressed. You'd think a cerebral person like Sheldon would want answers as to why he is the way he is. Only this question is never asked, let alone answered.

Sources: What Culture, Screen Rant, Vanity Fair, CBR