Main Page

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search

Welcome to the explain xkcd wiki!
We have an explanation for all 2345 xkcd comics, and only 41 (2%) are incomplete. Help us finish them!

Latest comic

Go to this comic explanation

26-Second Pulse
There are some papers arguing that there's a volcanic component, but I personally think they're just feeling guilty and trying to cover the trail.
Title text: There are some papers arguing that there's a volcanic component, but I personally think they're just feeling guilty and trying to cover the trail.

Explanation

In this comic strip, Science Girl is presenting her project on geology to her class mates, and is explaining some of the non-earthquake signals that seismometers detect. She describes a mysterious signal that repeats with a 26-second period. Scientists have exploited this signal to correct for clock drift in historic seismic records.

Science Girl initially provides a plausible explanation (some kind of natural wave pattern on the coastline of the Gulf of Guinea, which is in fact the most common theory about this signal). However, she quickly takes a turn for the dramatic when she claims that it might be a giant, murdered by seismologists, whose heart still beats. This is a reference to Edgar Allan Poe's short story The Tell-Tale Heart, in which the main character murders a man and hides his corpse beneath the floorboards, and then hears (or believes he hears) his victim's heart continuing to beat; the noise eventually drives him to confess his guilt to visiting police officers. (The narrator of The Tell-Tale Heart never uses that phrase in the story; he calls it a hideous heart.) "The Tell-Tale Heart" was previously referenced in 740: The Tell-Tale Beat.

Normal human hearts beat much more rapidly than once every 26 seconds, but large animals and hibernating animals may have much slower heart rates (which would include a giant at the bottom of the ocean).

The title text gives an alternate explanation for the seismic activity: volcanic activity, but Science Girl continues to believe in the giant story. In the last panel she references the common science meme that further research is needed, which has been mentioned several times in previous strips, including 2268: Further Research is Needed.

A seismometer is a device for measuring vibrations in the earth's crust, and one is likely in the collection of Cueball from 2060: Hygrometer.

Transcript

[Science Girl is standing in the front of a whiteboard holding a pointer up towards the board. Ponytail, Hairy, and Megan are sitting at desks facing Science Girl.]
Science Girl: When everything is still, seismometers pick up faint tremors we call seismic noise.
Science Girl: Most of it is from ocean waves, cars, etc. But there's also a mysterious 26-second pulse.
[Close up on Science Girl. She is holding a hand palm up towards the board behind her, showing a map with Africa in the center and some other continents at the edges of the view. A star is drawn within the country of Ghana, near the coastline.]
Science Girl: We've triangulated the source to somewhere in the Gulf of Guinea.
Science Girl: It comes and goes with the seasons, but it's been there since at least the 1980s. It's so regular we use it to sync up seismometers.
[In a frame-less panel only Science Girl is shown, once again in profile. She has the board behind her and points the pointer towards the board.]
Off-panel voice: What causes it?
Science Girl: Not sure. The most popular theory is that storm-driven waves set up some kind of resonance with the coast.
[Science Girl has leaned her stick on the board's tray. She has raised her clenched fists.]
Science Girl: Another theory is that long ago, seismologists murdered a giant and buried the body at sea.
Science Girl: Now we are haunted by the beating of its telltale heart!
Science Girl: Could be either.
Science Girl: Further research is needed.


Is this out of date? Clicking here will fix that.

New here?

Last 7 days (Top 10)

Lots of people contribute to make this wiki a success. Many of the recent contributors, listed above, have just joined. You can do it too! Create your account here.

You can read a brief introduction about this wiki at explain xkcd. Feel free to sign up for an account and contribute to the wiki! We need explanations for comics, characters, themes and everything in between. If it is referenced in an xkcd web comic, it should be here.

  • There are incomplete explanations listed here. Feel free to help out by expanding them!
  • We sell advertising space to pay for our server costs. To learn more, go here.

Rules

Don't be a jerk.

There are a lot of comics that don't have set-in-stone explanations; feel free to put multiple interpretations in the wiki page for each comic.

If you want to talk about a specific comic, use its discussion page.

Please only submit material directly related to (and helping everyone better understand) xkcd... and of course only submit material that can legally be posted (and freely edited). Off-topic or other inappropriate content is subject to removal or modification at admin discretion, and users who repeatedly post such content will be blocked.

If you need assistance from an admin, post a message to the Admin requests board.