In Star Trek they face many trials, wars, battles, what was the single worst catastrophe the federation faced, in reported casualties? Was it the battle of Wolf 359, an engagement in the Dominion war, when the Borg went back in time and assimilated all of Earth?

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    Would you count the series finale of TNG? Q convinces Picard to perform an action which causes a ripple back in time that prevents life from ever existing on Earth (and possibly other nearby planets?) So that essentially "kills" not just every human alive at the time, but every human (and other Earthly species) who ever lived. For humans alone, that's probably in the in the trillions somewhere, quintillions if you count non-human Earth species. If other planets were affected, who knows? Nov 9, 2015 at 14:28
  • @DarrelHoffman feel free to right it up if you can get some more details, it may not make the accepted answer but could potentially be a useful answer to have on hand.
    – Himarm
    Nov 9, 2015 at 14:42

5 Answers 5


50 Billion

See Richard's answer to What is the bloodiest war in the Star Trek universe?--the largest number killed due to a war on any of the Trek TV shows/movies was 50 billion (in an incident recalled by a powerful energy being known as a Douwd, in the TNG episode The Survivors--this particular Douwd had been disguised as a Federation citizen, and he destroyed the entire Husnock species after they destroyed the Federation colony he had been living in, just three days before the episode was set). In the novels, the highest number Richard found was 63 billion (during a Borg invasion of the Alpha Quandrant in the novel Lost Souls). And if you want only Federation deaths from TV shows or movies (as might be suggested by the line 'what was the single worst catastrophe the federation faced'), there is also the Federation/Klingon war shown in an alternate history in the TNG episode Yesterday's Enterprise, which was said to have resulted in 40 billion lives lost--and since the Federation was losing this war, it's a safe bet that the number of Federation lives was more than 20 billion, or at least, not significantly less than that (if you reject this one because it took place in an alternate timeline, please specify what timeline you are asking about, since the timeline that was created in the 2009 Star Trek movie is obviously different than the one most previous TV episodes and movies have been set in).

This question is not exactly a duplicate of that other question since that one was specifically about war while this one is about death counts from any causes, but I don't think there have been any natural disasters or other non-war-related incidents that have been shown to have killed a larger number.

  • Makes my 6 billion look puny! Nov 9, 2015 at 3:40
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    If you're going to go with alternate timelines as acceptable, I'll see your Yesterday's Enterprise and raise you the entire Galaxy: "The Federation's gone, the Borg are everywhere, we're all that's left!". Nov 9, 2015 at 9:32
  • @Shadur - Good point, the body count was probably high there, though it's possible they killed most of starfleet in a repeat of Wolf 359, and after that the assimilation of the galaxy was relatively bloodless (and assimilations shouldn't be included in the death count).
    – Hypnosifl
    Nov 9, 2015 at 13:47
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    @hyponosifl I think we most definitely should count assimilations as a fate worse than death. Nov 9, 2015 at 13:49
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    @Raphael - A battle between footsoldiers is different than a battle between ships, though--Russia was willing to sacrifice a huge number of soldiers because they had a large population but not enough of an industrial advantage to give them the equipment needed to make them as effective as individual German soldiers. I think with air or sea battles involving costly planes and ships, you'd find few if any cases where the winning side lost many more of these vehicles than the losing side. And we also have tended to see that Klingon ships are more sparsely crewed than Federation ships.
    – Hypnosifl
    Nov 9, 2015 at 20:23

Possibly over 18 billion

In the events leading up to Star Trek (2009), the planet Romulus is destroyed and its population of over 18 billion is wiped out when the Hobus star goes supernova — a tragedy that Spock tried, but failed, to prevent.

This event is documented in the (fully canon) Star Trek: Countdown comic book series and referred to in Star Trek (2009).

Because of the improved relations between the Federation and the Romulan Empire after Nemesis, and because of Spock's involvement in this incident, I am including this within the scope of the question.

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    Good call; I'd forgotten about that (duh - that's what led to the whole reboot franchise!) +1 Nov 9, 2015 at 3:41
  • @TheDoc : No worries, yours is good too and I also would have put Vulcan for my answer and just left it at that. :-) I recalled both incidents but had assumed for some reason that Vulcan had a larger population, until I looked them up (because of your answer).
    – Praxis
    Nov 9, 2015 at 3:46
  • Glad to have been of help then! :D Nov 9, 2015 at 3:56
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    Since Romulus is not part of the Federation, I assume you are interpreting "what was the single worst catastrophe the federation faced" to not be restricting the question to Federation deaths--but in that case, doesn't the incident in *The Survivors" where the Douwd recalled wiping out the entire Husnock civilization of 50 billion clearly beat this one?
    – Hypnosifl
    Nov 9, 2015 at 6:28
  • @Hypnosifl : Sure. I'm just offering a catastrophe that occurred to me that had not been listed by either you or the TheDoc. It's the OP's job to pick the answer that best fits his question. That being said, the Federation was actually involved in the Hobus incident. Spock was trying to stop it, and LaForge had designed Spock's special vessel for deploying the red matter. The Douwd were extragalactic beings recalling something that happened in the distant past, with no Federation involvement. It's difficult to compare them.
    – Praxis
    Nov 9, 2015 at 14:50

Every Earth-based organism that ever lived and maybe more

In the series finale of TNG, Q convinces Picard to perform an action which causes ripples back in time that prevents life from ever existing on Earth. Arguably, this could be considered "killing" every human who ever lived or will live, along with any non-human Earth species. Just taking humans into account, we're probably talking about trillions or even quadrillions (depending on how far into the future you want to consider). Counting every other species on Earth, those numbers would skyrocket by several orders of magnitude. And given that the anomaly is spreading (it was actually pretty far from Earth when they found it), it could affect many other inhabited planets as well. If it doesn't eventually stop, it could potentially end all life in the Universe.

Of course it was a Q-based scenario, and it was reversed by the end of the episode, and of course all those lives weren't actually ended so much as not started, but depending on how loose your criteria are for a life-ending event, this could qualify.


Possibly over 6 billion

In Star Trek (2009) when the planet Vulcan is destroyed in 2258 in the alternate timeline created by Nero's arrival, almost everyone on Vulcan was killed, which amounts to about 6 billion people - I doubt that there would be another single incident that had that many deaths.


There's also the uninhabited Dyson's Sphere (TNG, "Relics"), which size was equivalent to ~400 million Earths (according to Star Trek science consultant, Naren Shankar). Multiply that by the ~6 billion inhabitants just on one Earth. Even if only fraction of the Dyson's Sphere was populated, that would be well into the trillions gone. I can't remember if one of the crew said they all left due to the star's radiation issues, or did something suddenly happen with the star that wiped them out. Maybe someone can illucidate more on that.

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    There is no evidence that they died, in the episode they just say it was uninhabited
    – Burgi
    Nov 9, 2015 at 11:14

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