(notice:some morbid language ahead)

I have thought about putting it on a planet, but planet would be too lame and of little importance to the whole universe. And such 9/11 would only have a few million casualties, and also would be of little importance.

In my universe, stars are habitable objects equally to planets. And hypergiant stars have large publicity akin to "we are tiny, size comparisons of planets and stars". Kinda how USA is on Earth. But thought of buildings with billions of floors and city the size of an entire Earth orbit somewhat makes me dizzy. Like buildings the size of individual planets and stars are strange.

  • $\begingroup$ Welcome to worldbuillding. Please take the tour and visit the help center to better understand the scope of this community. Can you better explain your context and your question? It's rather fuzzy now, in particular the last section. $\endgroup$
    – L.Dutch
    Aug 12, 2018 at 10:08
  • 2
    $\begingroup$ This really sounds like something that should be refined as a question in the Sandbox before asking. As written it's just too broad, not least because your universe is unimaginably different and vast with no details. $\endgroup$ Aug 12, 2018 at 10:21
  • $\begingroup$ What places come to your mind that are known throughout your entire universe? $\endgroup$
    – Raditz_35
    Aug 12, 2018 at 11:06
  • $\begingroup$ This question started out on Writing as How big should Twin Towers be in my version of 9/11? $\endgroup$
    – user
    Aug 12, 2018 at 11:16
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    $\begingroup$ Considering that America had "only" a few thousand casualties while at the same time civil wars and diseases in Africa for example caused in the millions of casualties, all that you would need is a political entity ruling over a large enough space getting hit in a well-known place of political and/or economical importance. The amount of casualties wouldnt need to exceed anything more than 1000 and you can use it as a large enough tragedy. $\endgroup$
    – Demigan
    Aug 12, 2018 at 12:29

2 Answers 2


Trigger a supernova.

The closest safe distance between Earth and a supernova is 50 light years. There are 0.004 stars per cubic light year, meaning in the sphere of 50 light years around a star, there are almost three thousand stars. If each has a quadrillion inhabitants orbiting it, it would kill $3*10^{18}$ people. The life of all stars within a thousand light years you be affected, which is essentially "injuring" the planets, instead of "killing" them, as would happen if they were within 50 light years of the supernova. This would "injure" 24 million stars, about 1/2000th of the stars in our galaxy.

This supernova would also serve the inhabitants of the surviving stars to fear what would happen now that a terrorist organization could cause supernovas, and now that they knew that it is not against too many moral codes of the leaders of such organization.


If stars are habitable, what's the deal with planet cities?

Just think of that question. Some sci-fi go the extra mile and build an entire habitable ring around a star.

How to make the event important.

Just have a terrorist hijack the entire city-planet and... Well, fly it into the sun.

If you covered the Earth with a city, that city could support quadrillions of people. Imagine an entire planet that is nothing but housing.

Now this is how you make news worthy of the entire universe.


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