**(context, skip over if you want)**Imagine a type II alien civilization that spans a large portion of its galaxy. The only reason it’s gotten this far is becuase of their aggression, but there is another. A different civilization that spans most of the known galaxy has had a very bad past with our first one. Our first civilization wishes to take out the second with the help of special equipment that utilize rare dark matter. In my galaxy dark matter is harvested from black holes, so why not take out two birds with one stone by taking out enemy star systems as well as harvesting that juicy dark matter.

This comes to my question: How could an advanced civilization turn a star into a black hole?

Things to consider: Whatever type of contraption that has the ability to do this must not be extremely vulnerable, as it may face combat.

This civilization has access to a multiple Dyson sphere’s worth of energy. Essentially resources are not much of an issue (just don’t go too crazy.)

I’m ok with a little bit of handwavium

Please feel free to give feedback, ask questions, and give advice.

Edit: ok so I probably should have explained this. Regarding your comments I do know that dark matter is common and I know it’s probably not a good idea to get it from black holes, but, in my universe there are two kinds of dark matter: positive and negative. Positive makes up the known universe, its useful but not nearly as useful as the negative dark matter which is almost impossible to harvest without black holes.

Also, my question was “how to turn a star into a black hole” ,not something asking for a lecture about dark matter which we don’t even know that much about.

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    $\begingroup$ It's hard to know how to unpack "vulnerable," given that we're talking about a war being fought by a "Type II" civilization. What would not count as vulnerable to a foe that is too powerful to be steamrolled by the Type II civ? $\endgroup$
    – Tom
    Commented Dec 7, 2022 at 21:54
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    $\begingroup$ Here is a near duplicate question. Black holes are created by adding mass. Lots of mass. Is that the answer to your question? You might be asking what procedure would be used by your civilization to add that mass, but that's too broad for this Stack and violates the prohibition against answers being of equal value. (Keep in mind our no-brainstorming rule from the help center. Are we helping you solve a specific problem, or are you fishing for ideas?) $\endgroup$
    – JBH
    Commented Dec 7, 2022 at 22:53
  • $\begingroup$ A couple suggestions to make this a bit less against everything we know about the universe: dark matter isn't rare, it appears to be the majority of the universe. However, it is extremely diffuse: a solar system doesn't contain much, since it's spread out across the galaxy and the surrounding space. Second, in reality you're not getting anything out of a black hole...but maybe the dark matter's easier to catch when the black hole's gravity boosts it to a much higher energy than normally encountered. $\endgroup$ Commented Dec 8, 2022 at 1:31
  • $\begingroup$ You seem to be making up the science as you go along. This site isn't friendly to those looking for a prompt/boost/grist for their creative processes. Personally, I'd just fold space between the center of two stars. $\endgroup$ Commented Dec 8, 2022 at 2:54
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    $\begingroup$ The concept of harvesting dark matter from black holes is going to be painfully outdated as soon as we discover what dark matter is (and we already know it's not black holes). If the goal is to harvest energy from black holes, a more realistic hard sci fi implementation would be to extract kinetic energy from the ergosphere around a rotating black hole. $\endgroup$
    – Hene
    Commented Dec 8, 2022 at 10:23

2 Answers 2


Dump several other stars into said black hole

If they have all that energy, just keep merging stars until you get a black hole. When you slam another star into it, it'll probably go nova, which is pretty destructive, but you can just keep tossing stars at them till you get lucky.

  • $\begingroup$ You gotta love that sense of cooking. Mom? I blew up the kitchen again! Could you bring down another couple of stars so I can start over? BTW, do we know the odds of a black hole forming? And do we have an idea of how much mass to bring together quickly to raise those odds? Just curious. $\endgroup$
    – JBH
    Commented Dec 7, 2022 at 23:48
  • $\begingroup$ It depends on the star and how fast you slam them together. $\endgroup$
    – Nepene Nep
    Commented Dec 8, 2022 at 0:20
  • $\begingroup$ I’m sure there is a way, but, this doesn’t seem plausible. Moving many different stars into one would take a ton of time. I’m also not sure it would be worth giving up many different potentials for Dyson spheres and/or other black holes if there’s another solution. Aside from that, how would they move the stars thousands of light years? $\endgroup$ Commented Dec 8, 2022 at 1:10
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    $\begingroup$ This is how black holes work though. You get enough mass into a small area and a black hole forms. Also, stars are closer than other stellar masses, and if you have enough energy you can move them in a bunch of ways, like towing them with a massive engine on a gas giant. $\endgroup$
    – Nepene Nep
    Commented Dec 8, 2022 at 9:39
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    $\begingroup$ You could sci fi hand wave there to be a single, easier way, but then you can sci fi hand wave anything. $\endgroup$
    – Nepene Nep
    Commented Dec 8, 2022 at 16:21

You give the answer in the OP!

Q: How could an advanced civilization turn a star into a black hole?

A: with the help of special equipment that utilize rare dark matter.

You have your dark matter harvesters and you want to use that special equipment in your aggressive plan. Here is how!

You want dark matter in nice nuggets. You harvest primordial black holes.


Theoretical history Depending on the model, primordial black holes could have initial masses ranging from 10−8 kg[5] (the so-called Planck relics) to more than thousands of solar masses. However, primordial black holes originally having mass lower than 1011 kg would not have survived to the present due to Hawking radiation, which causes complete evaporation in a time much shorter than the age of the Universe.[6] Primordial black holes are non-baryonic,[7] and as such are plausible dark matter candidates

Your special equipment can manipulate these primordial black holes. You go after the little ones that have nearly evaporated. Ones that have accumulated a whole bunch of baryonic matter get unwieldy and you have wielding in mind.

Your people either use the primordial holes as they find them, or make their own micro black holes out of dark matter, replicating the events of the early universe that caused the primordial black holes.

One of these should do for a star. Chuck one in. The black hole will drink it up and become a larger black hole.


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