To Divide by Zero is an internet slang term describing an action that leads to an epic failure or theoretically unlikely disaster, such as an earth-shattering apocalypse or a wormhole in the time-space continuum. The concept of division by zero is also associated with the phrase "OH SHI-," which represents the response of someone that is cut off mid-sentence as a result of the disaster.
However, according to Encyclopedia Dramatica, the phrase is said to have originated on 4chan's /b/ (random) board, with its earliest dating to December 8th, 2006. In the thread, posters were sharing their chat logs with ChaCha.com search engine, one of which illustrated an Anonymous poster asking “do you know what happens when you divide by 0? things go BOOM so I hear." The question unacknowledged by the ChaCha representative.
In math with real numbers, values that represent quantities along a continuous line, division by zero is an undefined operation, meaning it is impossible to have a real number answer to the equation. This impossibility was first noted in philosopher George Berkeley's 1734 article The Analyst. Division by zero also occurs in computer programming, where an attempt to do so can lead to generation of an exception, error message, positive or negative infinity, or even crash the program being executed. The mathematic aspect of dividing by zero has been discussed on Drexel University's Dr. Math FAQ, MathIsFun.com, the Explain it Like I'm 5 subreddit, Popular Mechanics and the Physics Forums.
The “Divide by zero” comment soon began appearing outside of 4chan as well, with the earliest known instance found in the comments section of an article posted to gaming blog Joystiq on December 13th, 2006. The article, which described a series of satire articles aimed at the gaming blog written by another gaming blog The Game Rag, humorously proposed a challenge of recursive criticism:
Mr. Smart, we'd like to see you rag this article about you ragging our articles. Only then can you create a chain reaction of circular, never-ending prepositional phrases that cause a rift in time space, ultimately opening up a black hole that devours us all. Have at it, you!
In 2007, mentions of dividing by zero also appeared in fanart on deviantArt, the eBaum’s World forums, 4chan’s /v/ (video games) board and again on /b/. A definition for the phrase "divide by zero" as used in the context of 4chan was added to Urban Dictionary on September 22nd, 2007. In a 4chan thread from February 2008, an Anonymous poster suggested “OH SHI-” be the title for an imaginary video game-style achievement for successfully dividing by zero without creating a time paradox while posting on the site.
The joke took another turn in late 2008 with the launch of the Large Hadron Collider, the world’s largest and highest-energy particle accelerator built by the European Organization for Nuclear Research (CERN) to test the predictions of different theories in particle and high energy physics. Following the rise of unlikely speculations that the project could accidentally yield a tiny black hole on the surface of the Earth, the Large Hadron Collider quickly became associated with the humorous concept on 4chan. That same year, “divide by zero” was cited as an example of a 4chan meme in a Yahoo! Voices article about a DDoS attack on the site. Additionally, various image macros simulating hypothetical consequences of dividing by zero have appeared on FunnyJunk, Very Demotivational and Tumblr.
In June of 2015, users of Siri, the automated assistant for the iOS operating system, found that if you asked Siri "What is 0 divided by 0?", the assistant would respond with a long pre-programmed Easter Egg script. The assistant would respond:
“Imagine that you have zero cookies, and you split them evenly among zero friends. How many cookies does each person get? See? It doesn’t make sense. And Cookie Monster is sad that there are no cookies, and you are sad that you have no friends.”
Vine user Mark W Smith caught the retort in a Vine.
Users later found that the trick worked on users who had not upgraded to iOS8. The salty response quickly went viral in the vein of shit that siri says jokes, with celebrities such as Aaron Paul telling their followers to ask Siri the answer to the equation.
Ask Siri "what is zero divided by zero?" RIGHT. NOW.— Aaron Paul (@aaronpaul_8) June 30, 2015 (via Wayback Machine)
"Divide by zero" has a consistently large search interest since it can be applied to math and computer programming. "Dividing by zero" interest does not pick up until July 2005, which is several months before the first YTMND site was made.