In Star Trek 4, an unknown space probe travels to earth, "EMP"-ing everything on its way and almost destroying the planet by trying to talk to whales.

Are there any informations (extended universe) what that probe was or what it actually wanted? In the movie, it is simplified as the probe saying "hi", and after a short smalltalk, it goes away again, restoring the damage it has done.

Consider the following:

  1. When Kirk and his crew arrived in the past, they received the song of whales via comm. The signal was send from San Fransisco.
  2. Signals from earth travel at light speed max. The signal was send in 1986 and the probe arrived in 2286, meaning 300 light years of distance for the signal to travel. That is not much in interstellar travel, and well within Federation Space. If we assume the probe traveled with light speed, the "home" of the probe must be withing 150 light years. In the movie, it seems to be moving at less than warp, so it might be underway even longer. Has no one tried to track the probe?
  3. Sending a giant probe to a planet up to 300 light years away sounds very irrational considering the probe destroyed/disabled other star ships on it's way, just to say "hi whales"

I love the movie, but in the end, these facts confuse me alot.

  • 1
    The signal didn't end in 1986 though the signal ended when whales died out which isn't specified
    – user46509
    Commented Sep 24, 2015 at 12:07
  • Dupe of scifi.stackexchange.com/questions/99588/… ?
    – Valorum
    Commented Sep 24, 2015 at 12:41
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    I'm more interested of the origins of the probe, not the dialogue with the whales Commented Sep 24, 2015 at 12:59
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    Alexander Mills - Shouldn't you instead ask how the probe makers even knew whales where on Earth in the first place and that they stopped making whale songs? Whale vocalizations are vibrations in water which might have some slight effect and noise in air but certainly end at the top of the atmosphere and don't travel though the vacuum of space, let alone at speeds which could reach distant stars quickly. Commented Sep 26, 2015 at 5:08
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    Also, why the assumption that the home of the probe was the home planet of the message recipients? Maybe they happened to have a mothership within 150 light years at the time.
    – user11521
    Commented Apr 6, 2017 at 20:49

4 Answers 4


It appears that there was a sequel novel Probe that gives some more background about the "Whale Probe".

Kirk and his crew later discover that the Probe was created by beings that resembled Earth cetaceans

Spock successfully mind melds with the probe, learning that it did not seek to be destructive to other races, instead they were so different from its creators that they were ignored as "mites" in "metal bubbles", and teaches the probe to be more aware of what it is doing to humanoid life in the galaxy as it travels, leaving the probe to continue to explore the galaxy


Once the whales are brought back from the past, they are able to communicate with the probe and send it on its way. Creating this sequence created some behind-the-scene's controversy. Nimoy explains:

Morrison’s response had a wonderful, profound effect on my thinking about these issues. (And upon the Star Trek IV script, in which Spock tell McCoy, “There are other forms of intelligence on Earth, Doctor. Only human arrogance would assume the [probe’s] message must be meant for man.”) Because of that, I felt very, very strongly that we should not anthropomorphize the probe. Therefore, when the whales and the probe communicate, I felt we should make no attempt to “translate” their conversation for our human audience by using subtitles. To do so would demean the mystery . . . .

Unfortunately, not everyone agreed with me—including Harve Bennett. Because I felt so strongly on the subject, this led to friction between us, especially when Harve sent the studio heads a memo, suggesting some possible “dialog” between the probe and the whales . . . . It was only after a great deal of insistence that I convinced Paramount not to use the subtitles, and to let the mystery of the probe remain precisely that.
- I Am Spock, by Leonard Nimoy

  • Good answer, but you need to add a link to the quote you used.
    – Wad Cheber
    Commented Oct 15, 2015 at 7:38
  • @Wad Cheber, this quote is from the book "I Am Spock", by Leonard Nimoy. Commented Feb 29, 2016 at 13:42

In the movie, Spock asked Uhura to fine-tune the probe's transmissions, and ultimately it gave out the "whale songs".

Since at that time, about 2286, the whales had been long extinct, Spock deduced that this was a probe sent by aliens of whale species to check on what happened to their other inhabitants on Earth. This was not a routine check.

Maybe, the whales routinely contacted their species throughout the universe when they existed. Once they had been made extinct, the probe came searching for answers.

All of this was in the movie.

I would also like to reference the other answer given here, as it adds more detail to the movie's events.

  • Thank you for your answer :-) However (even if i didn't state this in my question) i was looking for informations that are not openly discussed in the movie, since the movie leaves more questions open than it answers Commented Sep 25, 2015 at 11:54

I have a theory about the Star Trek 4 probe....

I don't think the probe "lost contact" with the whales. That would imply that the probe has been to Earth before and there would be some sort of record of huge storms and EMPs in the past as the probe communicated with the whales.

Here's my theory... The probe was led to Earth because it intercepted the Voyager 2 probe (not to be confused with Voyager 6, aka V'Ger). The probe interfaced with the gold record on Voyager 2 and it only understood the whale songs on the record. It located Earth's location from the map on the record that was meant to help someone make their "first contact" with Earth. Now, if you search "Voyager gold record" on YouTube, then you'll notice that the audio of the whale song from the record is the EXACT same audio the whales sang in the movie! To add to my theory, there was some classical music on the record, one piece of which is the same as in the movie's end credits!

I personally think the director was hinting at the probe's origin and no one noticed...

  • 3
    Cool theory, and it seems to at least be based on evidence in the show. :)
    – Obsidia
    Commented Aug 8, 2017 at 20:17
  • are you saying Leonard Rosenman had music placed on Voyager? Because he was the composer of the film credits...fun theory but...
    – NKCampbell
    Commented Aug 8, 2017 at 21:16
  • Im not saying Rosenman's music is on the voyager record, however Bach's Brandenburg Concerto no 2 IS on the golden record. If you listen to the end credits,, you will hear parts of Bach's Concerto being used.
    – Cam
    Commented Aug 8, 2017 at 22:32
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    ah - yeah....that's quite a stretch in my opinion. You're talking a four note refrain from Bach that is at best alluded to, not straight copied by Rosenman (different notes) in the main title. Barring any other evidence, there is nothing in this answer that isn't wild speculation. Clever speculation but wild nonetheless
    – NKCampbell
    Commented Aug 9, 2017 at 1:54
  • The primary problem with this is Voyager 2 will still be within the Sun's SOI (which extends more than a light-year out) in the 23rd century.
    – Joshua
    Commented Feb 7, 2020 at 3:53

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