The Expedition Approximation Season 8, Episode 6 -  Aired October 20, 2014

The Expedition Approximation

Sheldon and Raj consider applying for a dark matter research expedition in a salt mine, but their friends don't believe they would be able to cope with the difficult conditions. Sheldon and Raj test their hardiness to heat and cramped conditions in the university's steam tunnel.

Meanwhile, Leonard and Penny get into an argument over money. When they seek their married friends' help on how to handle their finances as a couple, it sparks a disagreement between Howard and Bernadette.

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Writers: Steven Molaro (Story), Dave Goetsch (Story), Tara Hernandez (Story), Jim Reynolds (Teleplay), Steve Holland (Teleplay), Maria Ferrari (Teleplay)

Director: Mark Cendrowski

Viewers: 16.02 million Households Rating: 10.2/16 Adults 18-49 Rating: 4.6/14

Available on iTunes

Episode Notes

  • The title refers to Sheldon and Raj creating an approximation of their dark matter expedition, which would require them to work deep underground in a salt mine, in the university's steam tunnel.
  • The song Sheldon sings down in the "mine" is Dark as a Dungeon, a song by Merle Travis that was famously covered by Johnny Cash.

Episode Quotes

Sheldon: Are they making fun of us?
Raj: Yep.
Sheldon: I miss the old days when I couldn't tell.

Penny: Hang on. You guys are going to work in a mine?
Sheldon: Why not?
Penny: You had a panic attack when we went through the car wash!

Bernadette: Speaking of new careers, how are things going with dark matter, Sheldon?
Sheldon: Oh, I have to say it's the most exciting time in the history of the field.
Bernadette: Oh, what's going on?
Sheldon: I started doing it.

Raj: You call yourself a friend? I was trying to help you. And at the first sign of trouble you ran away, leaving me to fend off a family of rats! You're a completely selfish human being and a physical & moral coward.
Sheldon: His statements of the obvious continue to annoy.

Penny: Or maybe, now that I'm no longer an out-of-work actress who can't pay for her own dinner, that makes you a little insecure.
Leonard: I can't believe you would say that. You know how insecure I am about my insecurities.

News Stories

Title Date Posted
806 'The Expedition Approximation' Ratings October 21, 2014

Last night's The Big Bang Theory dominated the ratings in its time slot and for the night as a whole, finishing as the night's most-watched and highest-rated program by a considerable margin.  Full story

806 'The Expedition Approximation' Pictures October 9, 2014

Pictures from the October 20 episode of The Big Bang Theory, "The Expedition Approximation", have been added to our gallery. In the episode, Sheldon and Raj test whether they could survive a demanding expedition - and each other's company - by simulating the conditions in a steam tunnel. Meanwhile Leonard and Penny seek relationship advice from Howard and Bernadette after a fight over money.  Full story

806 'The Expedition Approximation' Press Release October 6, 2014

CBS has released the synopsis for the October 20 episode of The Big Bang Theory, "The Expedition Approximation". This is the last of the episodes to air on Monday night as the show returns to its Thursday home on October 30.  Full story


Sheldon and Raj are considering applying for a dark matter research expedition which would involve them working deep underground in a working salt mine. Their friends do not think they would be able to survive the dark, cramped and humid conditions down there. Raj and Sheldon soon decide to test their mettle by recreating the conditions of a salt mine in the university's steam tunnel.

While Leonard and Penny are having dinner, Penny gives Leonard an envelope full of cash, explaining that she sold the car Leonard bought her and is returning the money to him. This sparks a disagreement between Penny, who doesn't want to keep Leonard's money now she has a well paying job, and Leonard, who thinks she should still keep the money as it was a gift to her. Later, Leonard thinks of a solution to the problem: they should put the money in a joint account. Although they're both supportive of the idea, it doesn't end their disagreement as they both struggle to understand why money is now making them uncomfortable as a couple.

Sheldon and Raj go to the university's steam tunnel to see how they would survive in a salt mine. Amy is there to provide support from above. Meanwhile, Leonard and Penny go over to Howard and Bernadette's to discuss how they handle finances as a couple. Unfortunately, the conversation soon starts a fight between Howard and Bernadette. Penny and Leonard see Howard and Bernadette as an example of what not do to as couple.

Back in the tunnel, Sheldon is starting to feel unnverved by the conditions and starts singing to get his mind off his discomfort. Unfortunately, the mining song Sheldon sings, Dark as a Dungeon, only reminds them of the bad conditions. After a brief discussion about Miley Cyrus and Hannah Montana, Sheldon opens up to Raj over his feelings about his career change. His switch to studying dark matter has put him back at square one in his thirties, no longer a prodigy near the top of his field. Sheldon and Raj's bonding comes to an abrupt end when Sheldon sees rodents behind Raj and flees the tunnel, leaving Raj down there to fend of a family of rats.

Later that night, Leonard and Penny make up and have fun with the money by spreading it over their bed, Howard and Bernadette make up and turn their thoughts to Howard's birthday party, while Raj escapes from the tunnel and yells at Sheldon for abandoning him.