Main Page

Welcome to the explain xkcd wiki! We already have 12 comic explanations!

(But there are still 2032 to go. Come and add yours!)

Latest comic

 6/6 Time Title text: You know how einstein figured out that the speed of light was constant, and everything else had to change for consistency? My theory is like his, except not smart or good.

The original image has a link to a previous comic 1061: EST which is explained here.

Explanation

 This explanation may be incomplete or incorrect: Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.

Cueball here suggests a regional time system similar to that used in many societies prior to the invention of mechanical time keeping [[1]] Japan during the Edo period, where the day is separated into two parts based on night and day and then subdivided by hour, minute, and second to give season-variable lengths for each. The caption, though vague, can be assumed to relate to the gradual deviation of certain regions from the Coordinated Universal Time zones with "Daylight Savings Time" that is observed inconsistently and smaller regions opting for awkward fractional increments of deviation from Greenwich Mean Time.

The title text refers to Einsteins special theory of relativity which postulates that the speed of light is the same for all observers, regardless of the motion of the light source (or the observers). An observer at high speed measures the same speed of light as an observer with no motion, measured from the same light source. In classical physics the speed of the moving observer would be added up but in special relativity this isn't true, instead the time runs slower for the moving observer. And additional to this time dilation there is also a length contraction without which the geometry wouldn't work.

Transcript

[Cueball and White Hat are walking.]
Cueball: Under my time system, the sun rises at 6 am and it sets at 6 pm, as it should.
Cueball: The length of the second is different each day and night, and the current time shifts with your latitude and longitude.
Cueball: Today is one of the two days each year when my clocks run at the same speed as everyone else's.
[Caption below the panel:]
Time standards are so unfixably messy and complicated that at this point my impulse is just to try to make them worse.

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!

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 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.

Logo

Explain xkcd logo courtesy of User:Alek2407.