XKCD's log-scale map of the observable universe


41 Responses to “XKCD's log-scale map of the observable universe”

  1. nanuq says:

    The CN tower doesn’t get a mention? *&(*#((*&( Americans!

  • Kabur Naj says:

    One of my favourite XKCDs in quite a while. Both on account of the attention to scientific detail and the science fiction in-jokes. We’d expect nothing less from Randy than that he’d do his best to render the meso-scale objects appropriately distorted by the logarithmic axis. Kudos!

    That said, am I the only one that was disappointed that the observable universe apparently ends at the centimeter scale of grass blades? I think van Leeuwenhoek might’ve begged to differ had this cartoon been presented even 350 years ago. Or perhaps there is a sequel in the making? (Pretty please?)

    Also, since no one else seems to have mentioned it, this cartoon owes a huge spiritual debt to Charles and Ray Eames’ fantastic 1977 short film “Powers of Ten”. (Currently on YouTube, but probably not for long.) If you haven’t seen it, and you’re geeky enough to be reading these words, you owe it to yourself to go view it, or find it at your local library. You can also visit powersof10.com if you enjoy the film as much as I did.

  • Anonymous says:

    @13 – from Wikipedia:

    “As a result of following the free return trajectory, the altitude of Apollo 13 over the lunar far side was approximately 100 km greater than the corresponding orbital altitude on the remaining Apollo lunar missions. This could mean an all-time altitude record for human spaceflight, not even superseded as of 2008; however, the variation in distance between Earth and the Moon, owing to the eccentricity of the Moon’s orbit about Earth, is much larger than 100 km, so it is not certain whether the actual distance from Earth was greater than that of all other Apollo missions.”

  • Sunfell says:

    I liked the “Contact” reference!

  • aeflash says:


    There was a near instant request for a poster in the XKCD forums. (A thread is ritualistically created as soon as a new comic is posted.) So, it was due to popular request.

    Randall also makes a living solely from XKCD merchandising, so one can hardly blame him for monetizing his comic.

  • Kabur Naj says:

    Heheh… Randy is also a fan: xkcd.com/271/.

    @#29: You’d have to *know* where the lost planet of Magrathea *is* in order to accurately include Agrajag and the whale in this schematic. Randy has too much intellectual integrity to merely speculate on such things!

    (Higher than a kite! Nice.)

  • krebscout says:

    The poet part made me laugh in “Contact” – this was even better.

  • Anonymous says:


    I keep asking in the forums for him to fix the brainwaves on that chart and turn it into a poster. I know I would not be the only person to jump at the chance to have that on a wall.

  • rblakem says:

    I appreciated the Douglas Adams reference.

  • Kabur Naj says:

    Woo hoo! The sequel is here!
    xkcd #485

  • demidan says:

    Let’s all go bowling and eat a hotdog!

  • stwf says:

    Anyway, its actually just a map of the solar system, right?

  • Cory Doctorow says:

    Click through, STWF, goes a lot farther than that. Randall trained to be a physicist IIRC — so when he says, “Map of the observable universe,” he means it.

  • hawkins says:

    My favorite is the little spaceship in the asteroids. It’s a reference, of course, to the early-1980s arcade video game called “Asteroids.” See http://en.wikipedia.org/wiki/Image:Asteroi1.png

  • matisse says:

    No fnords in there.

  • Billegible says:

    WTB poster version please.

  • Billegible says:

    Ooh! There is indeed a poster in the store: http://store.xkcd.com/.

  • Ghede says:

    I’m a little ticked off about this one. Same time the comic goes up, front page updates: “By popular request, this is available in the Store!”


  • Billegible says:

    Ghede, just ’cause the rest of us can bend spacetime to make the request in advance is no reason to be jealous.

  • dragonfrog says:

    Cory – yes, Randall has a physics degree, and I think the early comics were drawn when he was working at NASA.

  • Anonymous says:

    I think the poet in the spaceship is a reference to Roger Zelazny’s “A Rose for Ecclesiastes” which I strongly recommend. Actually I recommend pretty much all Zelazny except the execrable “madwand” stuff. “Rose” and “Jack of Shadows” absolutely rule.


  • acrocker says:

    My favorite is definitely spacecat (not sure what the meme’s real name is) out past the milky way. http://img511.imageshack.us/img511/6725/spacecat1sp7.jpg

  • MaartenSneep says:

    I miss the “Oh, no, not again”-petunia and sperm whale in the drawing, but other than that, I think it is great.

  • Kieran O'Neill says:


    And I just finished reading Baxter’s Exultant, so cosmic-scale thinking is pretty high in my consciousness right now.

  • Mojave says:

    Was Apollo 13 really the Human altitude record? I would’ve thought all the Apollo missions flew more or less the same pattern around the moon…

  • franko says:

    i miss the whale & petunias, too, but i appreciate ford prefect.

    am i the only one who noticed that cory is higher than a kite?

  • zikman says:

    I like the Romulan neutral zone reference… and the futurama one. good stuff, as usual

  • Nadra says:

    I would guess that he was inspired by the princeton map: http://www.astro.princeton.edu/~mjuric/universe/
    But I like the XKCD version better – it will look nice on my wall!

  • Gunn says:

    I spent a happy hour reading about astrophysics and feeling good about the universe. Thank you, Randall, especially for mentioning the Great Attractor, my favorite object larger than the Milky Way.

    Now, back to Sarah Palin and John McCain.

  • SimplyAaron says:

    …and this is why I keep coming back to XKCD. Totally loved the Great Attractor’s inclusion, you couldn’t say it was the whole universe without Vonnegut!

    I am so buying the poster.

  • grimc says:

    I have a question: At what point does altitude become distance?

  • Anonymous says:

    I think you could probably guess ahead of time that this would be popular enough that all the geeks would want it in the store. It made it to BoingBoing, nuff said.

    I for one love the Rising Stars spaceship reference. I’m surprised I remembered that. (I CALL IT FIRST!)

  • ThreeFJeff says:

    GRIMC, the earth is round. It’s all up from here.

  • OM says:

    …This is incomplete. It’s lacking the “…But you should be *here*” tag.

  • grimc says:


    Trying to pull the ol’ ‘earth is round’ flimflam, eh?

    But seriously, I wonder if there’s a specific point where astronauts are told “From here on out, when speaking to Mission Control or reporters or even Mom, you are not x miles above the Earth, but x miles away.”

  • jphilby says:

    Pretty complete. This must have been done last week as it doesn’t include DARK FLOW.

    (Or DARK FLO, but that’s personal)

  • Anonymous says:

    I’m very sad that the dolphin from the Dolphin Olympics flash game didn’t make the cut. But oh well.

  • Teresa Nielsen Hayden / Moderator says:

    It goes well with his map of the Electromagnetic Spectrum.

  • Ahoj says:

    @16 I am missing the vonnegut reference, please let me in.

    the great attractor is an actual object. It’s the cause of the “local” large scale structure of the universe.
    and by local, I mean within the first 100 Megaparsecs.

  • bdashrad says:

    Seriously though, the Furturama reference is gold.

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