718: The Flake Equation

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search
The Flake Equation
Statistics suggest that there should be tons of alien encounter stories, and in practice there are tons of alien encounter stories. This is known as Fermi's Lack-of-a-Paradox.
Title text: Statistics suggest that there should be tons of alien encounter stories, and in practice there are tons of alien encounter stories. This is known as Fermi's Lack-of-a-Paradox.

[edit] Explanation

Ambox notice.png This explanation may be incomplete or incorrect: Currently a stub. Detailed explanation of parts and likely numbers needed.
If you can address this issue, please edit the page! Thanks.

The Flake equation is a parody of the Drake equation, which estimates the number of detectable extraterrestrial civilizations in our galaxy. It does so in similar manner: by multiplying number of stars by consecutive probabilities of the star having certain characteristics making detectable life possible. Just like the Drake equation, exact numbers are unknown, but can be estimated, and the equation shows the guesses about the values.

The equation assumes that a "credible-sounding" explanation is when someone misinterprets natural phenomena as alien sightings, someone imagines it because of mental illness, or someone thinks the story up on purpose. The probabilities in brackets estimates that one in 5000 people will belong to one of these groups. As many of them will keep the story for themselves, another numbers kicks in, telling us that roughly one person in 10 will tell anyone. Next two numbers estimate that about 100 people will be told about the incident for every person that "experienced" it and decided to share. Another number says that it is very likely that optional flaws will be filled or skipped while retelling. The last number accounts for the fact that not everyone can share the story with the audience.

The final results tells us that there should be about 100 000 stories about aliens that have reliable explanation. The data is obviously highly uncertain, and as with the Drake Equation, you can plug in your own numbers, but if you keep your guesses realistic, you will most likely get a very large number. This convinces the reader that the fact that there are many stories about aliens does not necessarily means that many people actually met aliens.

The title text refers to Fermi's Lack-of-a-Paradox as a parody of the Fermi paradox: The contradiction between the high estimated probable existence of extraterrestrial civilizations and the lack of establishing contact to such civilizations by humans.

Another comic parodying this equation is 384: The Drake Equation. The credibility of paranormal reports in general is revisited in 1235: Settled, which posits that if such phenomena were real they should have been unambiguously captured on camera by now.

[edit] Transcript

The Flake Equation:
P = WP × (CR + MI) × TK × F0 × F1 × DT × AU ≈ 100,000
WP = World Population (7,000,000,000)
CR = Fraction of people who imagine an alien encounter because they're crazy or want to feel special (1/10,000)
MI = Fraction of people who misinterpret a physical or physiological experience as an alien sighting (1/10,000)
TK = Probability that they'll tell someone (1/10)
F0 = Average number of people they tell (10)
F1 = Average number of people each friend tells this "firsthand" account (10)
DT = Probability that any details not fitting the narrative will be revised or forgotten in retelling (9/10)
AU = Fraction of people with the means and motivation to share the story with a wider audience (blogs, forums, reporters) (1/100)
Even with conservative guesses for the values of the variables, this suggests there must be a huge number of credible-sounding alien sightings out there, available to anyone who wants to believe!

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


There was a later comic about our capabilities' precluding of UFO sightings and such. I may find it at some point. --Quicksilver (talk) 02:51, 20 August 2013 (UTC)


googlesearch=site:explainxkcd.com ufo


Kevin McCready (talk) 13:25, 10 May 2014 (UTC)

Is there any significance to the word "flake"? Urban Dictionary says it stands for "unreliable person", but certainly not in context of alien sightings. -- 13:34, 26 August 2015 (UTC)

 It's a portmanteau of "Drake" and "Fake". -- 10:58, 4 February 2017 (UTC)
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?