485: Depth

Explain xkcd: It's 'cause you're dumb.
(Redirected from 485)
Jump to: navigation, search
↓ Skip to explanation ↓
The Planck length is another thousand or two pixels below the comic.
Title text: The Planck length is another thousand or two pixels below the comic.


The comic is a companion piece to 482: Height, which explored a logarithmic scale from the edge of the observable universe down to the Earth's surface. Depth continues the process, viewing logarithmically smaller scales from Earth's atmosphere down to the interior of a single proton. This combination is reminiscent of Charles and Ray Eames' 1977 short film Powers of Ten.

Here's a walk through the entire comic:

  • At the top, we see a cutaway view of a story apartment complex. From left to right, different activities can be seen in the apartments; Megan and Cueball playing in a ball pit, Megan exorcising Windows Vista, Ponytail and Megan playing Guitar Hero or a similar game, Cueball at a desk, and what appear to be some sexytimes.
  • The view descends into Cueball's tower PC.
  • Entering the computer's internals, we see a mouse plugged into the PS/2 (6-pin mini-DIN) connector. This is a visual pun, since the mouse is an actual rodent and not a handheld device.
  • Next, we dive into the CPU. We see a multi-layered pun on the question "how many angels can dance on the head of a pin?" There may be a pun with a chip's connector pin, but the more obvious reference is Randall's answer of 32,767 = 215 - 1, the largest possible value of a signed 16-bit integer. Adding one rolls back over to -32,768, which is 32,768 devils or "negative angels." (See 571: Can't Sleep for a similar joke and a more elaborate explanation.)
  • A blood-sucking mosquito appears to be "leeching" a torrent.
  • A segfault is a problem with memory access.
  • Dust mites are small arachnids that feed on house dust and are known to cause allergies. Rust mites are very small mites that live on plants and cause discoloration of leaves and fruit, or small galls.
  • We zoom in on a memory unit on the CPU. Cueball is being rickrolled, as indicated by the label "pixel on Rick Astley's shoulder."
  • A "fork();" command points at one of several unlabeled spermatazoa. Forking and sperm are capable of spawning "child processes."
  • Peter Norton is the founder of Norton Antivirus. He is shown fighting a biological virus, rather than informatic malware.
  • Showing the relative scale of carbon nanotubes, the suggestion is that these then lead on to a more megastructural Space Elevator, for which carbon nanotubes are often cited as a suitably strong component needed for the cable.
  • We soon zoom in on a silicon atom in the CPU. In the electron cloud, the squiggles made out of arrows are Feynman diagrams. A Feynman diagram in the shape of a stick figure is saying "Sup?", a pun on the "Sup" particle (supersymmetric partner 'squark' to the Up quark) and an abbreviation of the greeting "What's up?"
  • An 'iPod Femto' is shown, as a pun on the 'iPod Nano' (both are SI prefixes), both of which refer to units far smaller than any iPod that has ever, or likely will ever, be created.
  • Brian Greene is a theoretical physicist and pop scientist who discusses the nature of the universe. The picture of him knitting is a pun on string theory and PBS miniseries The Fabric of the Cosmos. The term 'knitting furiously' shows up in the 1857 Volume 14, page 46 (available via HathiTrust and Gale (preview)) of The Monthly Packet. Furthermore, Greene doing something furiously references "Colorless green ideas sleep furiously", a correctly-formulated sentence that nonetheless conveys no meaning or logic.
  • The Planck length (P) is the smallest theoretically measurable distance, defined by three fundamental constants in physics: the speed of light in a vacuum (c), Planck's constant (h), and the gravitational constant (G). The Planck length is vastly smaller than any known particle that isn't a point mass, and modern physics is a long way from investigating such a scale.


Sizes Accurate on a vertical log scale
[Series of images of characters doing various things. The things they are doing are listed in left to right order.]
Cueball and Megan playing in a ball pen
Megan using witchcraft to ban vista "Out, Vista!"
Ponytail and Megan play Rock Band
A couple is having sex under the cover in bed.
[Below this series of images, an image of a man on the computer.]
Cueball is on a computer and the image expands as it goes down. Here are the labels from left to right, up to down:
North Bridge
Mouse (rodent)
CPU Socket Pin
32,767 Angels Dancing (one more and they'd roll over and become 32,768 Devils), Rice, Torrent (a bug), CPU, upcoming segfault
dust mite
Data (a pixel on Rick Astley's shoulder), rust mite, fork();
Peter Norton fighting a bacteriophage
carbon nanotubes
space elevator
a line of silicon (Si), Electron Cloud, a man made out of arrows saying "sup?"
silicon nucleus
IPod femto
Brian Greene knitting furiously [next to his knitting needles there is text saying clink, clink]


  • The ballpit inside the apartment is a reference to 150: Grownups, in which Megan filled her apartment with playpen balls.
  • The structure next to the couple in bed could be an elliptical dish to increase the sound from their Loud Sex.
  • 1162: Log Scale and 482: Height are other comics about the use of log scales.
  • 271: Powers of One mocks the concept of getting cool effects by zooming in/out by, instead of a log scale, using powers of one.

comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!

Discussion 01:39, 3 September 2013 (UTC) Is the bed actually shaking or are the people/person under the sheet just moving on their own? The squiggle lines doesn't show. PS Oh, yeeeaaah! That's what being the first poster feels like, especially on an old comic that hasn't been touched for five years. Until now: at 4:38 am and 50 seconds, 2013/03/09. (GMT).

Three bugs:

1. In the explanation, someone forgot to mention how many stories high the apartment building is. I'd say it's at least two stories tall; possibly more, but if so, the upper stories are all obscured by foreshortening.
2. Still in the explanation, I disagree that the person at the computer on the second floor (between the Guitar Hero players & the bed) is our protagonist Cueball; he's on the first floor, under the Guitar Hero folks, sitting at his computer.
3. In the transcript, that person at the computer on the second floor is omitted. 06:34, 13 March 2014 (UTC)

It looks like the comment on Brian Greene may also refer to Noam Chomsky's "Colorless green ideas sleep furiously" -adamaustin (talk) 21:28, 13 March 2014 (UTC)

Does the last room on the right contain an ellptical reflector dish? I think I can barely make one out on the edge of the comic. 23:35, 22 August 2019 (UTC)