from September 22, 2011 to May 10, 2012 over 24 episodes.

Cast

Dr. Leonard Hofstadter, portrayed by Johnny Galecki, is an experimental physicist with

an IQ of 173 who received his Ph.D when he was 24 years old. He shares an apartment with

colleague and friend, Sheldon Cooper. He and Penny dated at one point during the series,

but they broke up during season 3. They start dating again in season 5, though their relationship

is rocky. Dr. Sheldon Cooper, portrayed by Jim Parsons,

is a theoretical physicist. Originally from East Texas, he was a child prodigy, starting

college at the age of 11, right after completing the fifth grade. He received the Stevenson

award when 14 and received his Ph.D when he was 16. He has an IQ of 187 and exhibits a

strict adherence to routine; a lack of understanding of irony, sarcasm, and humor; and a complete

lack of humility or basic empathy. He is dating Amy Farrah Fowler, when he asked her to be

his girlfriend. Penny, portrayed by Kaley Cuoco, is a waitress

who lives across the hall from Sheldon and Leonard. She has aspirations to an acting

career, but has not been particularly successful thus far, only boasting a few small roles

as well as a part in a hemorrhoid commercial. She and Leonard dated during season 3 and

broke up. In the finale episode of Season 4, she was thought to have slept with Raj

after drinking, but Raj revealed to her they did not. During season 5, Penny begins to

date Leonard again though their relationship is rocky. Her last name has never been revealed.

Howard Wolowitz, portrayed by Simon Helberg, is an aerospace engineer. He is Jewish, and

lives with his mother. Unlike Sheldon, Leonard, and Raj, Howard lacks a Ph.D. He defends this

by pointing out that he has a master's degree in Engineering from MIT and the equipment

he designs is actually built and launched into space, unlike the purely abstract work

of his friends. He provides outrageous pick-up lines and fancies himself a ladies man with

suitably unimpressed reactions from Penny. Though he finds that he has limited success

with other women at first, he begins dating Bernadette in season 3, but they break up.

They get back together in the Season 4 episode "The Hot Troll Deviation", become engaged

in the episode "The Herb Garden Germination" and are married in the last episode of this

season. At the end of the season, he goes on a Russian Soyuz rocket to the International

Space Station. Dr. Rajesh "Raj" Koothrappali, portrayed by

Kunal Nayyar, is an astrophysicist originally from New Delhi, India. Known commonly as "Raj",

he works alongside Sheldon exploring the string theory implications of gamma rays from dark

matter annihilations. He is very shy around women and is physically unable to talk to

them unless he drinks alcohol. His sister, Priya, dates Leonard in season 4 and part

of season 5. Dr. Amy Farrah Fowler, portrayed by Mayim

Bialik, is a neurobiologist. Raj and Howard meet her on an online dating site using a

fake account for Sheldon. She is very similar to Sheldon, except that she is more open to

social interaction and thus more susceptible to conventional behavior. She becomes close

friends with Sheldon, prompting regular assertions from him that she is a girl and is his friend,

but she is not his girlfriend. She finally became his girlfriend when Sheldon decides

to change the course of their relationship after he becomes jealous when Amy goes out

on a date with comic book store owner Stuart Bloom. Amy also forms a quirky friendship

with Penny, whom Amy frequently refers to as her "bestie" and becomes Bernadette's Maid

of Honor at her and Howard's wedding. Dr. Bernadette Rostenkowski, portrayed by

Melissa Rauch, is a microbiologist. Bernadette is introduced to Howard by Penny while the

two were working together at the Cheesecake Factory. At first she and Howard do not get

along, as they appear to have nothing in common. When they find out that they both have overbearing

mothers, however, they feel a connection. She was upgraded to main cast status in the

episode "The Hot Troll Deviation", in which she and Howard revisit their previously unsuccessful

relationship. She and Howard get engaged, and much comical fodder is created through

similarities between Bernadette and Mrs. Wolowitz. She marries Howard at the end of this season.

Production Several high-profile celebrities appear in

the season. In "The Transporter Malfunction", actor Leonard Nimoy appears as a voice actor,

playing an action-figure Spock that Sheldon imagines talking to him. In the following

episode, "The Hawking Excitation", cosmologist Stephen Hawking appears as a guest star. Astronaut

Mike Massimino appears in "The Friendship Contraction" and "The Countdown Reflection".

Stephen Hawking went on to appear in the season 6 episode "The Extract Obliteration" and the

season 7 episode "The Relationship Diremption". Mike Massimino later appeared in the season

6 episodes "The Decoupling Fluctuation" and "The Re-Entry Minimization".

The season finale depicts Howard Wolowitz traveling to the International Space Station

on board a Soyuz rocket. Thanks to technical consulting from Astronaut Mike Massimino,

who also plays himself on the show, the production crew was able to put together sets that realistically

depicts the Soyuz capsule and the ISS. The Soyuz capsule was constructed based on photos

from NASA, the Kansas Cosmosphere for dimensions, and scavenged parts from an aerospace junkyard

in Los Angeles. Release

Critical reception On Rotten Tomatoes, 100% of seven critics

gave the season a positive review. Oliver Sava of The A.V. Club gave the season

a B+ rating. He described Raj as the "weak link of the show" as he has not "[evolved]

like the rest of the cast" and is "trapped in season one mode". Sava gave high ratings

to episodes where Raj did not feature prominently, such as "The Pulled Groin Extrapolation" or

"The Russian Rocket Reaction" and described "The Wiggly Finger Catalyst" as "one of the

series' worst", giving it a D+ rating. Sava's favorite relationship on the series is between

Amy and Penny. Jenna Busch of IGN disliked the previous season

but said that season 5 "is far more balanced"; Busch gave season 5 episodes ratings between

5.5 and 9, with an average rating of 8.0. She also noted that the show has "matured"

by included other women in the main cast. Tom Gliatto from People gave the season 3

out of 4 stars, stating that it is "bright and obvious as a cartoon, yet written with

a clean, precise patter of jokes". Awards

At the 64th Primetime Emmy Awards, The Big Bang Theory was nominated for Outstanding

Comedy Series, but Modern Family on ABC won. The show was also nominated for Outstanding

Technical Direction, Camerawork, Video Control for a Series and Outstanding Multi-Camera

Picture Editing For A Comedy Series. Jim Parsons was nominated for Outstanding

Lead Actor in a Comedy Series for "The Werewolf Transformation", but lost out to Jon Cryer.

Mayim Bialik was nominated for Outstanding Supporting Actress in a Comedy Series for

"The Shiny Trinket Maneuver", but lost out to Julie Bowen.

Distribution The season premiered on CBS on September 22,

2011. It was released on DVD with an aspect ratio of 16:9 format on September 11, 2011

in Region 1, on September 2, 2012 in Region 2 and October 3, 2012 in Region 4. The episodes

can also be streamed on Netflix or purchased on Amazon Instant Video or the iTunes store

in the US. Episodes

Penny regrets her sleeping with Raj and has become very good friends with Leonard, Leonard

breaks up with Priya, Amy pushes Sheldon in their relationship eventually becoming boyfriend

and girlfriend, Penny and the other women become a clique of their own, Howard prepares

for his wedding and going into space to the International Space Station and Leonard asks

Penny out as they begin "Leonard and Penny 2.0".

Ratings U.S. Nielsen ratings

Canadian ratings Australian ratings

This season began airing on the Nine Network on October 10, 2011 at 7:30 pm.

Notes a Due to an error in Australian ratings data,

"The Skank Reflex Analysis" and "The Infestation Hypothesis" were averaged with repeat episodes

that aired the following night for the weekly rankings. As a result, both episodes' ratings

significantly decreased to 1.225 million and 1.321 million viewers respectively. Based

on the original unadjusted figures, the episodes would have ranked first and third for the

week. These were unadjusted preliminary figures. UK ratings

The season aired Thursday nights at 8pm on E4. All viewing figures and ranks are sourced

from BARB. ^ a b Viewers in millions

^ a b Rank for individual channels only References