XKCD's log-scale map of the observable universe

Today's XKCD is epic in scope -- a log-scale map of the observable universe from top to bottom, with many in-jokes (including me!) and pop culture references. How many can you decode? Height (Thanks to everyone who suggested this!)



  1. 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.

  2. 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!”


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

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

  5. 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.


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

  7. 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…

  8. …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.

  9. 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!)

  10. @#18

    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.”

  11. @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.

  12. @8

    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.

  13. 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?

  14. @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.”

  15. 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.

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

    (Or DARK FLO, but that’s personal)

  17. 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.

  18. 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.)

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