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"The Colonization Application" is the seventeenth episode of the eighth season of the American sitcom The Big Bang Theory. The episode aired on Thursday, March 5, 2015.


Amy and Sheldon decide to get a turtle together, while Sheldon is planning on applying to be one of the first colonists on the planet Mars. Leonard and Penny don't want to be a boring couple and Raj is snooping around Emily's apartment.

Extended Plot[]

As Penny and Leonard climb the stairs Leonard is very excited saying that he was totally unstoppable and in the zone. Penny brings him down because it was only miniature golf and she beat him. As they enter apartment 4A, Sheldon is glad they have returned because he and Amy have some exciting news. Amy and Sheldon announce that they are taking their relationship to the next level which really confuses Leonard and Penny. They are getting a pet together, a turtle. While Penny jokingly says that she keeps saying they should stock champagne on ice for occasions like this, Leonard congratulates them. He wonders out loud that who would have thought that Amy and Sheldon would be the first couple in their group to start a family! Amy is delighted that she had the same thought.


We're getting a turtle!!

In Emily‘s apartment, Raj and Emily have gotten together for movie night. Raj can spend the night because her roommate won't be back since Emily murdered her (or not). Raj reminds her that their agreement was for her to say "just kidding" when she was kidding about having killed someone. She also tells him that she would never hurt him making Raj a little uncomfortable. Emily gets a call from the hospital to check up on a patient. Raj is staying in the apartment until Emily gets back. And her roommate is in another city, or at least her torso is. She adds that she was just kidding since she used the wood chipper.

At the pet store, Sheldon can't stand walking by all the puppies. Then they try and pick out a turtle. The first one Amy suggests looks like a jerk to Sheldon.  Sheldon likes one that is barely moving. Sheldon asks the turtle if he wants to come live with him even though they don't live in the same house. Amy reassures it that that is not the turtle's fault as if it was a child of divorce. The turtle will stay at Amy's if Sheldon is away, at Comic-Con or on Mars. Mars? Sheldon announces that he is putting in an application to be one of the first colonists on Mars. Amy is shocked, especially since he didn't consult her. She would not have approved of it. 

While making out on the couch, Leonard admits to Penny that he had gotten her a Valentine's Day gift, but was too embarrassed to actually give it to her since he bought it at the dirty book store. He got an artistic present which Penny thinks he got at Michael's. It's a canvas and body paint to use while having sex. Penny loves it.

Howard is playing a video game while Bernadette is doing their taxes. She has a lot of receipts from the Lego Store that Howard says are business expenses. Raj calls Howard while he is Emily's bedroom since he is alone. Raj opens the drawer of her bed bureau and can't get it closed. Raj doesn't want her to know he has been snooping. The he breaks the drawer trying to fix it. Bernadette hears what is going on and tells Howard that she is going to miss her. 

Leonard and Penny inspect their canvas and are not happy with it. They didn't move around enough and vow that they can do better because they are not old and boring. Leonard is fine with trying again in thirty minutes after he recovers.

Sheldon and Amy are returning from the pet store without a turtle because the turtle bit him. Sheldon was trying to get the turtle to like him. Amy wonders why he even bothers since he is planning to leave Earth the first chance he gets. Even though the chances of him being picked is small, it still hurts her that he didn't ask her before filling out the application. How he can survive another {{w|planet when he barely survived his turtle bite? Sheldon tries to cheer her up by playing the Star Trek theme on his nose. She is still mad.

In Leonard and Sheldon's apartment, Amy is still fuming and wonders why he even wants to go to Mars. He shows her his application video which answers that question. On the video Sheldon says how intellectly and hygienically clean he is, and how much fun he would be. He demonstrates his wacky sense of humor on a long voyage by smashing a pie in Leonard's face. 


Leonard and Penny's expression of their love.

After their second canvas, Penny is getting paint out of Leonard's eye because she wouldn't let him wear safety goggles. 

Howard has Raj nailed the front back on the drawer. As Emily returns they get into a fight over his snooping. Bernadette mentions that if they break up, it will be too bad because she likes her. 

In Penny's bedroom the new canvas is much more colorful and they are happy with the results. Penny refuses to hang a picture made by their butts in her apartment. To make sure it doesn't go to waste, they plan to give it to Sheldon and tell him that it was painted by William Shatner.

Raj talks to Emily 4

I hope you didn't look in my closet.

Amy decides to leave. Even though she thinks it sounds silly, she thought that getting a turtle together meant something to him. Sheldon chases after Amy who is mad since they were supposed to make plans for a future that's not on different planets. Sheldon asks Amy if they have to be on Earth? Are you suggesting we could go together? Sheldon wants her to go. Amy hugs him tightly as they go to file an application video together. Amy says that they could be the first to procreate on Mars. Sheldon tells her that she just can't keep it in her space pants. She also mentions that their kids would be Martians. Sheldon likes that idea. 

Raj and Emily are together in bed after she forgave him. Then she asks if he looked in her closet and Raj says no. "Good," she replies smiling and then she goes to sleep. Raj looks worried as he eyes the closet, and then her.



  • Title Reference: The title refers to the application Sheldon is making to become one of the first colonists on Mars.
  • Taping date: February 10, 2015
  • This episode was watched by 18.17 million people with a rating of 4.8 (adults 18–49).
  • Total viewers including DVR users 23.32 million.
  • The Big Bang Theory was ranked #2 for the week ending 8 March 2015.
  • This episode aired in Canada on March 5, 2015, with 4.49 million viewers with a weekly ranking of #1.
  • In the United Kingdom, this episode aired on Thursday, April 30, 2015, on E4.
  • In Australia, it aired on April 6, 2015, with 0.99 million viewers.
  • After the closing credits, a small tribute to Leonard Nimoy appeared, who passed away February 27.
  • Episode transcript [1]
  • Chuck Lorre's vanity card [2]


  • Jesse Schedeen at IGN - (T)he turtle was mere setup for the real conflict of the week - Sheldon's casual reveal that he had applied to join the Mars One colony. Amy was understandably upset by this revelation. Sheldon has long had a habit of making big decisions without consulting his girlfriend of several years...Sheldon's never really learned his lesson or even apologized for his actions. He merely swayed Amy with the promise that they'd fill out an application for her, too. Her character deserved better than that. The poetic justice outcome would be for the show to flash-forward a couple years, revealing that Amy, not Sheldon, is selected to join Mars One.
  • IMDb user reviews [3]


Sheldon Cooper, Ph.D

Ph.D. Physics, California Institute of Technology

  • Sheldon's doctoral diploma, notably seen in "The Parking Spot Escalation", can be clearly read in this episode. It reveals he obtained a Ph.D. in physics from Caltech.
  • Sheldon and Amy's idea of taking their relationship to the next level is to get a pet together.
  • Emily's apartment is seen for the first time.
  • This episode marks the 100th appearance/episode of Amy.
  • Amy mentions that she and Sheldon should be planning a future together for the first time. She even jokingly wants the turtle to call him "daddy".
    • In their future, they never have kids on TBBT, but Sheldon does mention that they had kids in his "Young Sheldon" narration.
  • It is illegal in California to sell turtles under four inches in length to prevent children from putting them in their mouths and contracting Salmonella.
  • It was implied that Penny and Leonard watched "Orange Is the New Black" on Netflix. She's wondering if the show is a drama or comedy.
  • Sheldon enjoys Amy's hug when she grabs him tightly after asking her to join him on Mars showing advancement in their relationship.
  • Leonard and Penny's plot in this episode is, in some ways, a belated Valentine's Day story for this season, due to the Mrs. Wolowitz death arc taking over the episode airings in February.
  • The seldom seen left front corner of the apartment is seen. Last seen in "The Euclid Alternative" (S2E5).  
    Leonard looks at computer

    Leonard's corner.

  • Second episode where a main character gets pie up their nose. First was "The Re-Entry Minimization" (S6E4).
  • Second episode where a main male character volunteers for a mission to outer space without consulting his girlfriend. First was "The Russian Rocket Reaction" (S5E5).
  • Howard, Bernadette], Raj and Emily share no scenes with Penny, the 'Shamy' duo [Sheldon & Amy] and Leonard in this episode.
  • According to Penny, Leonard (up until just recently) kept his socks on whenever in bed or having sex. This was proven true in "The Bozeman Reaction" when Leonard was seen wearing his socks after Sheldon interrupted him and Penny. This is also backed up in "The Recombination Hypothesis", when Leonard was wearing his socks after having sex with Penny within his daydream.
  • The final time that Howard and Bernadette's Apartment is seen in the series.
  • Howard and Bernadette are only seen at their apartment in this episode. 
  • The 200 dollar R2-D2 Howard mentions in "The Locomotive Manipulation" (S7E15) is referenced once again when Bernadette does their taxes. 


Emily: (voiceover) I can’t believe you don’t trust me.
Bernadette: She sounds really mad.
Howard: We should hang up.
Bernadette: Yeah, we should.
Howard: But we’re not going to, are we?
Bernadette: Not a chance.
Howard: What happened to snooping is wrong?
Bernadette: (she is now very cross) Howard, you’re going to jail for tax fraud. Who cares?
(Howard now looks his wife for one last second)

Sheldon: Oh, good. You’re back.
Amy: We have some exciting news.
Leonard: Okay.
Sheldon: As you know Amy and I have been together a long time and a lot of things I never thought possible now seem possible.
Penny: Okay.
Amy: After a careful evaluation of our relationship weave decided that the time was right to take a step forward.
Leonard: Okay.
Sheldon: Do you want to say it?
Amy: Let’s say it together.
Sheldon/Amy: We’re getting a turtle!
Penny: This is why I've been saying we should keep Champagne on ice.

Leonard: Who would have you two would be the first in our group to start a family?
Amy: That’s what I said!

Raj: And are you sure your roommate’s not coming back while I’m here alone ‘cause that would be awkward?
Emily: Oh don’t worry, she’s in Palm Springs.
Raj: Oh, good.
Emily: Well, her torso is. Just kidding. I put her in the wood chipper.

Sheldon: Hi, little guy. How’d you like to come home with us? Ah, you’ll be living with me because we don’t live in the same house.
Amy: But that’s not your fault. Like you we’re taking it ridiculously slow.

Leonard: So where do you want to hang it?
Penny: What? Are you kidding? We’re not hanging it.
Leonard: But it’s an expression of our love.
Penny: And our butts. Not hanging it!
Leonard: Seems a shame to throw it away.
Penny: Yeah. (Gasps) We can give it to Sheldon and tell him William Shatner painted it.

Sheldon: Do you want me to withdraw my application?
Amy: What I want is to be planning our future together.
Sheldon: And in that future, are we on the same planet? Yes, because I've seen people make long-distance thing work.
Sheldon: Does that planet have to be Earth?
Amy: Are you asking me to go to Mars with you?
Sheldon: I am. If I’m going to a barren, lifeless environment where the chances for survival are slim to none, I want you there with me.
Amy: (Hugs Sheldon)

Amy: You know, we could also be the first people to procreate on Mars.
Sheldon: You just can’t keep it in your space pants, can you?
Amy: Thinks about it. If we had a family there, our kids would be Martians.
Sheldon: They would, wouldn't they?

Raj: Thank you for forgiving me.
Emily: It’s okay. At some point we were bound to have our first fight.
Raj: Well, it almost happened when you called my apple pie crust doughy. The truth is you were right and I was just angry at myself.
Emily: Can I ask you one thing?
Raj: Of course, what?
Emily: Did you look in my closet?
Raj: No. Just the drawer.
Emily: You promise you didn't look in the closet?
Raj: I promise. Why, what’s in there?
Emily: Don’t worry about it. Good night. (Kiss) (Raj looks worried as Emily turns over and smiles.)



  • [4] Taping Report by Dana1010 and Danii