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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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?


Trip asks Hoshi if she has seen The Andromeda Strain (1971). Like Star Trek: The Motion Picture (1979), that film was directed by Robert Wise. 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.
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References The Andromeda Strain (1971) See more »


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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")

17 of 17 people found this review helpful.  Was this review helpful to you?

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