Main Page

Explain xkcd: It's 'cause you're dumb.
Revision as of 15:42, 8 August 2012 by Waldir (Talk | contribs)

Jump to: navigation, search

Welcome to the explain xkcd wiki! We already have 11 comic explanations!

(But there are still 1660 to go. Come and add yours!)

Latest comic

Go to this comic

Astronomy (or "astrology" in British English) is the study of ...
Title text: Astronomy (or "astrology" in British English) is the study of ...


Contrails (short for "condensation trails") are trails of vapor produced by aircraft exhaust, and are composed primarily of water. The Chemtrail conspiracy theory claims that contrails lasting unusually long are actually chemical or biological agents sprayed into the air for sinister purposes. Here, White Hat notices that there are a lot of contrails in the air. Cueball corrects him, saying that in American English, contrails are called chemtrails. This, however, is incorrect.

This is another comic in the My Hobby series. Many of these comics involve Cueball giving misleading information about pedantic terms, such as 1405: Meteor.

The title text implies that astronomy and astrology are synonymous, though astrology is used in British English. However, this is incorrect. Though both involve studying celestial objects, astrology is used as a means of predicting the future, while astronomy is the scientific study of celestial objects.

Contrail stands for “condensation trail”, which is the trailing cloud often found after jet planes that fly by. Itʼs formed from water sublimating on jet fuel exhaustions, some impurities of which provide bases for ice crystals to cumulate on. Some would dissipate in minutes, but others can last for hours or even longer.

Chemtrail, specifically referring to contrails that last for very long, is a conspiracist term that states such clouds can last so long because there are other chemicals added in jet fuel, thus achieving malicious results. Itʼs not approved by scientific community.

The joke is that British English and American English often call the same object with different terms, and one can often learn new words for a simple thing. This, however is not the case in this comic; contrail and chemtrail do not refer to the same thing, the latter being only a part of the former. And it being xkcd, we can assume that chemtrail is a term that is frowned upon. Thus the comic states it as misinformation.

The title text includes a similar situation: astronomy is serious study about things in outer space, like stars, planets, and galaxies. Astrology, however, is a system that infers one’s personalities and characteristics from zodiacs of her date of birth, which is a constellation assigned to a period of time in a year. The same system can also derive predictions about future, especially that of a relationship. Some would argue that astrology shows statistical values, but itʼs hardly science as by the standard of scientific community.


[Cueball and a man with a white hat are walking. White hat is looking up to the sky.]
White hat: Lots of contrails today.
Cueball: Oh, you must be from the UK. In American English it's "Chemtrail".
[Caption under the panel]
My hobby: Spreading linguistic misinformation

New here?

Feel free to sign up for an account and contribute to the explain xkcd wiki! We need explanations for comics, characters, themes, memes and everything in between. If it is referenced in an xkcd web comic, it should be here.

  • List of all comics contains a complete table of all xkcd comics so far and the corresponding explanations. The red links (like this) are missing explanations. Feel free to help out by creating them!


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 posting such are at risk of being blocked.

If you need assistance from an admin, feel free to leave a message on their personal discussion page. The list of admins is here.

Explain xkcd logo courtesy of User:Alek2407.

Personal tools


It seems you are using noscript, which is stopping our project wonderful ads from working. Explain xkcd uses ads to pay for bandwidth, and we manually approve all our advertisers, and our ads are restricted to unobtrusive images and slow animated GIFs. If you found this site helpful, please consider whitelisting us.

Want to advertise with us, or donate to us with Paypal?