The Terminator Decoupling

Leonard (Johnny Galecki), Sheldon (Jim Parsons), Howard (Simon Helberg) and Raj (Kunal Nayyar) are heading to San Francisco to attend a conference, where cosmologist George Smoot is giving a keynote address. On Sheldon's insistence, they travel on the Coast Starlight train. On board the train, they learn that Summer Glau (played by herself) is riding the same train. Raj and Howard debate on who should approach her first. With Raj unable to talk to women except when under the influence of alcohol, he departs to find alcohol on the train. As Howard is trying to figure out the best opening line, Raj swoops in and starts talking with Summer (even using the same line Howard planned to use: "It's hot in here, it must be Summer"). Their conversation is going very well (Howard commenting, "Normally around women, he has the personality of a boiled potato. Put one beer in him, and he’s M. Night Charmalarmalon.") However, Howard then points out to Raj that he is drinking non-alcoholic beer, after which he realizes he was under a sort of placebo effect, and quickly departs the scene, unable to talk anymore. Howard tries to strike a conversation but is unable to create an impression; instead he just comes off as annoying. Finally he asks to have his picture with her to which she agrees until he gets annoying again and she breaks his phone. With the failure of both Raj and Howard, Leonard musters the courage to approach Summer, but she gets off the train as he is introducing himself.

During the train ride, Sheldon realizes that he has forgotten the flash drive containing the paper he wanted Smoot to read. Reluctantly, he resorts to asking Penny (Kaley Cuoco) to actually enter his bedroom and locate his flash drive so she can email him the paper. When Sheldon eventually presents the paper to Smoot (appearing as himself) and proposes joint research on the subject, Smoot rejects his idea, leaving Sheldon to think Smoot is a diva.

George Smoot had written to the producers of the show and requested to appear on an episode of the series.[2][3] Smoot, who received the Nobel Prize in Physics in 2006 for his work which cemented the Big Bang theory, is an admitted fan of the series.[4] The scene involving Smoot was shot at the Warner Brothers Studios in Burbank, California on February 18, 2009.[4] Summer Glau also appeared as herself in the episode. Glau was part of the cast of Terminator: The Sarah Connor Chronicles which, along with The Big Bang Theory, was produced by Warner Bros. Television. Bill Prady, a co-creator of The Big Bang Theory, presented the script of the episode to Josh Friedman, creator of Terminator: The Sarah Connor Chronicles with the plan of casting Glau as herself. Friedman, impressed with the story, suggested it to Glau.[5]

On its first broadcast (March 9, 2009), the episode was watched by 9.46 million households, according to Nielsen ratings. The episode received a 3.6 rating/10 share among viewers aged between 18 and 49, and a 2.4 rating/8 share among viewers between 18 and 34.[6]

The episode received modestly positive reviews. Noel Murray of The A.V. Club praised the writers for evenly including all the main characters in the episode.[7] IGN's James Chamberlain found Glau's acting lacking emotion, remarking "it felt as though Cameron were on the show and not Summer".[8] Alan Sepinwall from The Star-Ledger also remarked this episode as a balanced one for the cast ensemble.[9]

• "The Terminator Decoupling" at IMDb
• "The Terminator Decoupling" at TV.com