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    What If? (xkcd)

    what-if.xkcd.com · Personal blog · on HN since 2012

    Randall Munroe, the xkcd creator, answers absurd hypothetical questions with physics, math, and careful research.

    Visit blogHN submissions
    SciencePhysicsCulture & Society
    What HN says

    Commenters recommend it for readers who like explainers on scientific answers to ridiculous hypotheticals, and praise how it treats silly questions seriously.

    Stats for nerds
    613HN people shared it
    132linked in comments
    1.9Kstory points
    Oct 2025last shared
    2013people per year2025

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    What HN people wrote when they linked it

    • n00bdudeMay 2021

      > Somewhat related: The current popular version of the story of "King Arthur" is a mix of a bunch of books written by different unrelated authors https://en.wikipedia.org/wiki/King_Arthur#Medieval_literary_... Are you imagining something like that?

      Yes - pretty much exactly like that.

      To make an analogy, kind of like “cryptopunks” in the world of crypto - except instead of “images” you buy & use as profile pictures, these characters have “behaviors, traits, persona, etc.” (revealed in the story) that a wannabe writer can reinvent & use to write an original short story, movie, novel etc. (but has to be copyleft licensed CC BY-SA)

      > Somewhat related: Before launching the "What if?" serie in https://what-if.xkcd.com/ he wrote the first five stories just to be sure that following his idea it was possible to write some interesting post.

      I have written 2 part short stories, but your idea of connecting “unrelated” short stories sounds a next step

      The stories are pretty good .. maybe I should make more of them free? I have zero lit community to talk to about this so I do much appreciate you helping me “conceptualize” this & providing the resources by which to offer comparisons / explanation..

      Maybe I’ll just give them all away for free. (Almost am at that point anyway) In any case, will share with you in comment a short story I wrote to give you an idea the kind of story. Thanks again - and if you’ve any more thoughts I’ll check by here

      Enjoy your Sunday

    • shagieJul 2025

      > let's hope nobody drills a hole in the Moon

      https://what-if.xkcd.com/46/ - while it deals more with the Earth (which has a more molten core), its still applicable. There's still molten material ( https://science.nasa.gov/moon/composition/ ) but it's a lot deeper.

      > (or blows the Moon up)

      As a classic Neal Stephenson (great world building, good plot... and it ends)... Seveneves starts with:

      > THE MOON BLEW UP WITHOUT WARNING AND FOR NO APPARENT reason. It was waxing, only one day short of full. The time was 05:03:12 UTC. Later it would be designated A+0.0.0, or simply Zero.

      ... and given the book and the "what happens"... a watch surviving (much less keeping the phase of the moon) would be impressive.

      There's also the Dr. Who take ("Spoilers") https://youtu.be/pHOnGSFzd3Y

    • gus_massaMay 2021

      I think you need to write at least two interlaced stories before submitting it here, because otherwise the idea is difficult to understand. (This is my recommendation, not an official hard rule.)

      Somewhat related: The current popular version of the story of "King Arthur" is a mix of a bunch of books written by different unrelated authors https://en.wikipedia.org/wiki/King_Arthur#Medieval_literary_traditions Are you imagining something like that?

      Somewhat related: Before launching the "What if?" serie in https://what-if.xkcd.com/ he wrote the first five stories just to be sure that following his idea it was possible to write some interesting post. (I can't find the post where he describe this.) I recommend to try your method and write at least 2 stories.

    • ooternessAug 2023

      The idea of something with ten solar masses moving so fast still terrifies me. It's just mind-boggling to think about something at that scale completing an orbit in the blink of an eye.

      I am reminded of Randall Monroe taking about the sheer energy of a supernova:

      > Which of the following would be brighter, in terms of the amount of energy delivered to your retina:

      > A supernova, seen from as far away as the Sun is from the Earth, or

      > The detonation of a hydrogen bomb pressed against your eyeball?

      > Applying the physicist rule of thumb suggests that the supernova is brighter. And indeed, it is ... by nine orders of magnitude.

      https://what-if.xkcd.com/73/

    • WillAdamsJun 2025

      My grandfather lived in a time when commercial hunting was outlawed.

      I worry that I live in a time when commercial fishing is not sufficiently regulated so that rather than being outlawed, it will simply become infeasible, with the attendant knock-on affects of countries which depend on the oceans for a significant portion of their protein.

      There are now a greater tonnage of ships in the ocean than bony fish:

      https://what-if.xkcd.com/33/

      What will be the next marker to be dropped?

      Makes one wish that we could manage something like to Hal Clement's "Raindrop":

      https://www.goodreads.com/book/show/939760.Music_of_Many_Spheres

    • WowfunhappyNov 2023

      This is a really great link!

      > Getting to space is easy. It's not, like, something you could do in your car, but it's not a huge challenge. You could get a person to space with a small sounding rocket the size of a telephone pole. The X-15 aircraft reached space just by going fast and then steering up.

      > But getting to space is easy. The problem is staying there. [...] To avoid falling back into the atmosphere, you have to go sideways really, really fast.

      This image accompanies the above excerpt: https://what-if.xkcd.com/imgs/a/58/orbit_x15.png

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