---
title: "The Big Bang Theory"
chunk: 4/11
source: "https://en.wikipedia.org/wiki/The_Big_Bang_Theory"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:04:29.021226+00:00"
instance: "kb-cron"
---

The Canadian alternative rock band Barenaked Ladies wrote and recorded the show's theme song, which describes the history and formation of the universe and the Earth. Co-lead singer Ed Robertson was asked by Lorre and Prady to write a theme song for the show after the producers attended one of the band's concerts in Los Angeles. Coincidentally, Robertson had recently read Simon Singh's 2004 book Big Bang, and at the concert he improvised a freestyle rap about the origins of the universe. Lorre and Prady phoned him shortly thereafter and asked him to write the theme song. Having been asked to write songs for other films and shows, but ending up being rejected because producers favored songs by other artists, Robertson agreed to write the theme only after learning that Lorre and Prady had not asked anyone else.
In October 2007, a full-length (1 minute and 45 seconds) version of the song was released commercially. Although some unofficial pages identify the song title as "History of Everything," the cover art for the single identifies the title as "Big Bang Theory Theme." A music video also was released via special features on The Complete Fourth Season DVD and Blu-ray set. The theme was included on the band's greatest hits album, Hits from Yesterday & the Day Before, released on September 27, 2011. In September 2015, TMZ uncovered court documents showing that Steven Page sued former bandmate Robertson over the song, alleging that he was promised 20 percent of the proceeds, but that Robertson has kept that money for himself.

=== Actors' salaries ===
For the first three seasons, Galecki, Parsons, and Cuoco, the three main stars of the show, received up to $60,000 per episode. Their salaries rose to $200,000 per episode for the fourth season, then went up an additional $50,000 in each of the following three seasons, culminating in $350,000 per episode in the seventh season. In September 2013, Bialik and Rauch renegotiated the contracts they held since they were introduced to the series in 2010. On their old contracts, each was making $20,000–$30,000 per episode, while the new contracts doubled that, beginning at $60,000 per episode, increasing steadily to $100,000 per episode by the end of the contract, as well as adding another year for both.
By season seven, Galecki, Parsons, and Cuoco were also receiving 0.25 percent of the series' back-end money. Before production began on the eighth season, the three plus Helberg and Nayyar looked to renegotiate new contracts, with Galecki, Parsons, and Cuoco seeking around $1 million per episode, as well as more back-end money. Contracts were signed in the beginning of August 2014, giving the three principal actors an estimated $1 million per episode for three years, with the possibility to extend for a fourth year. The deals also include larger pieces of the show, signing bonuses, production deals, and advances towards the back-end. Helberg and Nayyar were also able to renegotiate their contracts, giving them a per-episode pay in the "mid-six-figure range", up from around $100,000 per episode they each received in years prior. The duo, who were looking to have salary parity with Parsons, Galecki, and Cuoco, signed their contracts after the studio and producers threatened to write the characters out of the series if a deal could not be reached before the start of production on season eight. By season 10, Helberg and Nayyar reached the $1 million per episode parity with Galecki, Parsons, and Cuoco, due to a clause in their deals signed in 2014.
In March 2017, the main cast members (Galecki, Parsons, Cuoco, Helberg, and Nayyar) took a 10 percent pay cut to allow Bialik and Rauch an increase in their earnings. This put Galecki, Parsons, Cuoco, Helberg and Nayyar at $900,000 per episode, with Parsons, Galecki, and Helberg also receiving overall deals with Warner Bros. Television. By the end of April, Bialik and Rauch had signed deals to earn $500,000 per episode each, with the deals also including a separate development component for both actors. The deal was an increase from the $175,000–$200,000 the duo had been making per episode.

== Recurring themes and elements ==

=== Science ===
Much of the series focuses on science, particularly physics. The four main male characters are employed at Caltech and have science-related occupations, as do Bernadette and Amy. The characters frequently banter about scientific theories or news (notably around the start of the show) and make science-related jokes.
Science has also interfered with the characters' romantic lives. Leslie breaks up with Leonard when he sides with Sheldon in his support for string theory rather than loop quantum gravity. When Leonard joins Sheldon, Raj, and Howard on a three-month Arctic research trip, it separates Leonard and Penny at a time when their relationship is budding. When Bernadette takes an interest in Leonard's work, it makes both Penny and Howard envious and results in Howard confronting Leonard and Penny asking Sheldon to teach her physics. Sheldon and Amy also briefly end their relationship after an argument over which of their fields is superior.
As the theme of the show revolves around science, many distinguished and high-profile scientists have appeared as guest stars on the show. Astrophysicist and Nobel laureate George Smoot had a cameo appearance in the second season. Chemical engineer and Nobel laureate Frances Arnold portrayed herself in the 12th season. Theoretical physicist Brian Greene appeared in the fourth season, as well as astrophysicist, science popularizer, and physics outreach specialist Neil deGrasse Tyson, who also appeared in the twelfth season. Cosmologist Stephen Hawking made a short guest appearance in a fifth-season episode; in the eighth season, Hawking video conferences with Sheldon and Leonard, and he makes another appearance in the 200th episode. In the fifth and sixth seasons, NASA astronaut Michael J. Massimino played himself multiple times in the role of Howard's fellow astronaut. In the sixth season, NASA astronaut Buzz Aldrin had a cameo appearance. Bill Nye appeared in the seventh and twelfth seasons.

=== "Nerd" media ===