Star Trek: Enterprise: Season 4, Episode 11

Observer Effect (21 Jan. 2005)
"Enterprise" Observer Effect (original title)

TV Episode  |  TV-PG  |   |  Action, Adventure, Drama
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Ratings: 8.0/10 from 344 users  
Reviews: 3 user | 1 critic

Noncorporeal aliens inhabit the bodies of Enterprise crew members to study how the crew reacts to a lethal virus infection that has afflicted Trip and Hoshi.


(as Mike Vejar)


(based upon "Star Trek" created by), (created by), 3 more credits »
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Title: Observer Effect (21 Jan 2005)

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Episode cast overview:


Trip and Hoshi are returning from a visit to a planet where the Klingons once landed. Nothing interesting could be found, but in the shuttle pod back Trip suddenly starts coughing. A while later he collapses. Dr. Phlox finds out they are infected by a silicon-based virus. He estimates that the pathogen will kill them in five hours. Meanwhile an alien species seems to have taken over Mayweather and Reed. They are discussing the behavior of the Humans. For 10000 years they have been observing the reactions to the viruses to measure the intelligence of the infected species. Will the crew surprise them? Written by Arnoud Tiele (

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Release Date:

21 January 2005 (USA)  »

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Did You Know?


When trying to break the lock-out code of the decon chamber, Hoshi says that math is just another language. With that, she repeats the same opinion T'Pol has once voiced in Star Trek: Enterprise: Vox Sola (2002), when Hoshi was struggling with the equations of an alien language. The fact that she succeeds in this instance shows that she has evidently mastered the "language" of math in the meantime. See more »


[first lines]
["Reed" and "Mayweather" are playing chess]
Alien inhabiting Ens. Mayweather: You win in eight moves.
Alien inhabiting Lt. Reed: You're really starting to get a feel for the game.
Alien inhabiting Ens. Mayweather: 32 pieces, 64 squares - it's not as if it's difficult. Total number of possible outcomes is limited.
Alien inhabiting Lt. Reed: Ten to the 123rd power.
Alien inhabiting Ens. Mayweather: That's what I mean. Chess is so predictable. I'm surprised anyone bothers to play it.
See more »


References MacGyver (1985) See more »


Where My Heart Will Take Me
Written by Diane Warren
Performed by Russell Watson
Episode: {all episodes}
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User Reviews

Human Compassion
11 April 2010 | by (Rio de Janeiro, Brazil) – See all my reviews

Commander Trip and Hoshi are contaminated by a silicon based virus in a planet visited by Klingons and are kept in quarantine by Dr. Phlox. He researches with T'Pol an almost impossible cure since Trip and Hoshi have only five hours. Meanwhile Lieutenant Reed and Ensign Travis are the hosts of two non-corporeus advanced life forms that want to observe the human behavior in the stressed conditions caused by the incurable virus.

"Observer Effect" is one of the best episodes of "Enterprise". The engaging story has great performances and dialogs, and the conclusion is excellent with Archer giving a lesson of one of the most beautiful characteristics of the human beings: compassion. My vote is ten.

Title (Brazil): "Observador" ("Observer")

15 of 15 people found this review helpful.  Was this review helpful to you?

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worse ending to a Great Series ever! nwalters11
Humanoid alien females billandbonnie
10 Years with no Star Trek Series! grauhase
Same annoying mistakes as original series. ranb40
What I disliked about this series... ksjazzguitar
Just watched entire series on Crave and enjoyed it. sherrisomerville
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