In addition to friendship and romance, the characters' careers are also a huge area of focus on The Big Bang Theory. The Big Bang Theory follows four scientists, two of whom are roommates, as they navigate their lives in and out of their work at the university. Many of their more humorous interactions is the result of their interactions with people outside of the academic world, like Penny, but their careers still play a huge role in the series.

After all, a majority of Sheldon's quirks are related to his fascination and dedication to the sciences. With everyone working in the sciences (aside from Penny when she was a struggling actress), work isn't just the topic of conversation at dinner; it's their livelihood. The gang has fun at work because they're passionate about what they do. But what exactly do the characters on The Big Bang Theory do? Each character works in a different field, but that doesn't keep them from sharing their experiences, problems, and accomplishments with each other.

Raj

Astrophysicist

Raj's (Kunal Nayyar) work doesn't often get the spotlight since more attention is paid to Sheldon, and even Howard's, career goals. His work, however, isn't so far removed from Sheldon's. After attending the University of Cambridge, Raj got his PhD in astrophysics and became an astrophysicist at Caltech.

As much as Sheldon acts like he's smarter than everyone else and doesn't need to work in teams.

While at Caltech, Raj was part of the squad that created a data-collecting space probe on Pluto and ended up winning multiple awards for his research. Later, he teamed up with Sheldon to work on string theory and dark matter. As much as Sheldon acts like he's smarter than everyone else and doesn't need to work in teams, Raj's input was invaluable and helped Sheldon tremendously. By the end of the series, Raj was still working at Caltech but got a job at the Griffith Observatory as a hobby.

Sheldon

Theoretical Physicist

One of the brightest characters on The Big Bang Theory is Sheldon Cooper (Jim Parsons). He skipped several grades of school as a child and went to university very early. At the tender age of 16, Sheldon received his PhD, but he also has his Bachelor of Science, Master of Science, Master of Arts, and his Doctor of Science. With an IQ of 187, Sheldon works at Caltech as a theoretical physicist focusing on string theory.

He later changes his focus to dark matter when he hits a dead end with his study of string theory. However, Sheldon never completely lets string theory go. With Amy's help, they put their energy towards string theory's super-asymmetry and won a Nobel Prize for their accomplishments together. By the end of the series, Sheldon is still profoundly happy at Caltech working in the Physics Department.

Leonard

Experimental Physicist

After attending Princeton and getting his PhD in physics, Leonard (Johnny Galecki) became an experimental physicist at Caltech, which is where he met his three best friends. As an experimental physicist, Leonard actually gets to see how things work in the lab instead of listing mathematical equations on a board like so many of his colleagues.

His work was published in a few prominent journals, and he was recognized for his contributions to science. This resulted in his career when he began working for the U.S. government with Howard and Sheldon. He even got to work on the North Sea with a team organized by the legendary Stephen Hawking. At the end of the series, Leonard was at a standstill professionally but still did amazing work that was recognized by both Sheldon and President Siebert.

Howard

Engineer & Former Astronaut