explain xkcd - User contributions [en]

1193: Externalities

2013-04-06T00:49:42Z

70.79.36.61:

{{comic
| number = 1193
| date = April 1, 2013
| title = Externalities
| image = externalities.png
| titletext = Mouse over words and things to see where they come from.
}}

==Explanation==
{{incomplete}}
This comic isn't a static image - even the title text changes depending on which part of the image you're hovering over. The blank regions in the above image are dynamically generated from various sources.

*The university that is being recruited changes depending on which university is winning the hash finding competition in the fifth panel.
*The company doing the recruiting is randomly selected from a pool of companies. It was formerly the first NASDAQ-100 company mentioned on a varying Wikipedia page.
*The text in the second panel may vary: See [[1193: Externalities#Second Panel|this section]].
*The text in the third panel may vary: See [[1193: Externalities#Third Panel|this section]].
*The text in the fourth panel may vary: See [[1193: Externalities#Fourth Panel|this section]].
*The text in the fifth panel [[1193: Externalities#Fifth Panel|changes]], depending on which university is currently in third place in a hash finding competition. Clicking on the panel takes you to [http://almamater.xkcd.com/ a webpage] where people can enter their school's domain name and hash data, and ranks schools on how close their students can come to matching a Skein 1024 1024 hash value.
*The text in the top half of the sixth panel may vary. See [[1193: Externalities#Sixth Panel|this section]]. The second half of the panel is always the same.
*The last panel varies with the amount donated to the Wikimedia Foundation via [https://donate.wikimedia.org/?utm_medium=socialmedia&utm_campaign=xkcd_april1 this link]. For past images, see [[1193: Externalities#Seventh Panel|this section]].

===Hashing Competition===
For the two days until comic 1194 appeared, a competition was underway to see who could come closest to breaking a [[wikipedia:Skein_%28hash_function%29|Skein hash]]. The first text line of the first panel contains a link to http://almamater.xkcd.com. This page contained the text:

:Currently looking for Skein 1024 1024 input matching 5b4da95f5fa08280fc9879df44f418c8f9f12ba424b7757de02bbdfbae0d4c4fdf9317c80cc5fe04c6429073466cf29706b8c25999ddd2f6540d4475cc977b87f4757be023f19b8f4035d7722886b78869826de916a79cf9c94cc79cd4347d24b567aa3e2390a573a373a48a5e676640c79cc70197e1c5e7f902fb53ca1858b6

On this page, users were invited to enter "Your school's domain name"—presumably intended to be their college alma mater. (At least in the beginning, only a few top-level domains were accepted.) If the user entered an acceptable domain (by xkcd's rules, which apparently changed during the 48 hours of the competition), he could then enter data values one at a time. For each data value entered, xkcd returned a hash value and the number of bits by which it differed from the target value. The object was to achieve the lowest possible number of differing bits, ideally zero.

A ranking page showed the lowest value achieved for each domain name entered, but not the data that achieved it. The first name on the list was substituted in various panels, and the third-place school showed in panel five. No data values were reported by xkcd, but various results were posted by users of the xkcd forums and on other websites, leading to copycat submissions, so that occasionally large numbers of institutions would show the same moderately low value.

After the end of the contest, the data submission page vanished, replaced by the final list of rankings, which shows that Carnegie Mellon University achieved the best score with 384 bits incorrect out of 1024. The rankings only show a few hundred out of the several thousand domains submitted—presumably Randall chose to chop the copycat submissions off the end of the list, retaining only honestly obtained results.

===First Panel===
In some cases, Megan's reply seems to correspond to the company.
{| class="wikitable table-padding"
|-
|
:Hey, [university] students!
:Have you applied to [company] yet?
:Megan: The recruiter hasn't emailed me back in over three minutes.
|-
|
:Hey, [university] students!
:Have you applied to [company] yet?
:Megan: The recruiter hasn't emailed me back in over an hour!
|-
|
:Hey, [university] students!
:Have you thought of a career at [company]?
:Megan: I'm not that good at math.
|-
|
:Hey, [university] students!
:Have you thought of a career at [company]?
:Megan: What do they even do?
|-
|
:Hey, [university] students!
:Have you thought of a career at [company]?
:Megan: I don't like monopolies.
|-
|
:Hey, [university] students!
:Have you thought of a career at [company]?
:Megan: Only in my darkest moments.
|-
|
:Hey, [university] students!
:Be part of the Apple experience!
:Megan: I'm not really a fan of turtlenecks.
|-
|
:Hey, [university] students!
:Come work at Microsoft!
:Megan: I only came to this tech talk for the xbox giveaway.
|-
|
:Hey, [university] students!
:Y U No Work Yahoo?
:Megan: I like working from home!
|-
|
:Hey, [university] students!
:Become a partner at Starbucks!
:Megan: But green's not my colour.
|-
|
:Hey, [university] students!
:Come work in the Amazon!
:Megan: I don't have to actually move to South America, do I?
|-
|
:Hey, [university] students!
:Have you thought of a career at [company]?
:Megan: Not after that presentation.
|-
|
:Hey, [university] students!
:Thought about working for Intel?
:Megan: I'm not that great at division.
|-
|
:Hey, [university] students!
:Dude, you should work at Dell!
:Megan: That catchphrase is so old.
|-
|
:Ahoy, carnegie melonites!
:Have you thought of a career at [company]?
:Megan: Not after that presentation.
|-
|
:Hey, [university] students!
:Have you looked for a job at Kraft Foods?
:Megan: I'm allergic to sugar
|-
|
:Hey, [university] students!
:How about working for Whole Foods?
:Megan: Could I afford the food if I did?
|-
|
:Hey, [university] students!
:Come work at EBay!
:Megan: Maybe if they made a good bid.
|-
|
:Hey, [university] students!
:Come work for Activision... er... Blizzard... er...
:Megan: Activision Blizzard?
|-
|
:Hey, [university] students!
:Come find your future at Baidu!
:Megan: But nothing about Tiananmen Square.
|}

===Second Panel===
The text in the second panel is based on the company in the first panel:
{| class="wikitable table-padding"
|-
|
:When the Singularity happens, it will happen here.
:Ponytail: [Company] has outgrown us.
:Men: It is time.
|-
|
:Think of ways to make things smaller and smaller!
:Ponytail: I'm worried mine is too big.
:Men: Yeahhh
|-
|
:Think of ways to make things smaller and smaller!
:Ponytail: But will it blend?
:Men: Yeahhh
|-
|
:You'll be part of a dynamic research team envisioning the future.
:Ponytail: It probably looks cool.
:Men: Yeahhh
|-
|
:You'll be creating the future of commerce platforms!
:Ponytail: More recommendations.
:Men: Yep.
|-
|
:You'll be an insignificant cog in our giant machine
:Ponytail: We should improve Notepad
:Men: Nah
|-
|
:We can't tell you what you'll be working on.
:Ponytail: [Confidential]
:Men: [Redacted]
|-
|
:You'll be an insignificant cog in our giant machine
:Ponytail: Needs more Bob.
:Men: Nah
|-
|
:You'll help set the future of the company
:Ponytail: Wait. You hired a college grad as the CFO?
:Men: Yeahhh
|-
|
:At Qualcomm, we know you're born mobile.
:Ponytail: Born mobile!
:Men: Texting!
|-
|
:Short or tall, we've got a grande job for you!
:Ponytail: How many job openings are there?
:Men: Ele-venti or so.
|-
|
:You'll help direct the future of nutrition
:Ponytail: Microwaveable toast
:Men: Delicious
|-
|
:Help us find and provide the best healthy, local, and sustainable products.
:Ponytail: Hey guys, how about kale cookies?
:Men: Sounds great!
|-
|
:We're the Classmates.com to Facebook's Craigslist.
:Ponytail: Maybe we should use game theory.
:Men: Why Bother?
|-
|
:Whatever. Come create the future of gaming!
:Ponytail: Call of Duty 14.
:Men: That's genius!
|-
|
:It takes great minds to stifle other great minds.
:Ponytail: Let's block Canada
:Men: Sounds good.
|}

===Third Panel===
{| class="wikitable table-padding"
|-
|We're a convenient four hour drive from New York City (15,000 hours by roomba)
|-
|Only a short commuter flight away!
|-
|Travel to us by roomba, we're *that* close!
|-
|We're so close you can get to us by roomba.
|-
|Free roomba rides every morning while you have coffee.
|-
|Your roomba comes in black & slate, or white & silver
|-
|Just a short roomba ride up the coast, try not to fall off.
|-
|We know what everyday life is like for your generation:
|}

===Fourth Panel===
{| class="wikitable sortable plainlinks table-padding"
|-
|Our recruiting team is on the lookup for promising young [university] graduates.
|-
|We hired a new recruiting startup to help us hire [university] students.
|-
|We borrowed the botanical gardens' net to catch promising recruits.
|-
|We prefer to recruit from [university] students, of course.
|-
|Our recruiters are on the hunt for unaware [university] graduates.
|}

===Fifth Panel===
{| class="wikitable table-padding"
|-
|Or students from [university], if they're clever with their applications
|-
|Possibly [university] grads, if their form-filling startup works out.
|-
|Or [university] graduates, provided any of them manage to fill out the application correctly.
|-
|Or [university] graduates, if they manage to fill out the application correctly.
|}

The text in the form varies independently of the text at the top, sometimes related to the organization in 3rd place:

{| class="wikitable table-padding"
|-
!Organization
!Name
!Email
!Education
|-
|MIT
|Oliver Smoot
|pgp encrypted
|have you ever really looked at the fourier
|-
|
|Wheeeee
|ford.com
|stealing lunches from startups
|-
|CMU
|leeroy jenkins
|me@car
|I can cut up melons
|-
|CMU
|pittsburgh
|me@car
|I can cut up melons
|-
|
|SEGMENTATION FAULT
|save trees
|Contra dancing.
|-
|Cambridge
|I'm applying
|cam.gov
|on going problems with birds
|-
|
|certainly
|elephant
|An excellent year in the Sahara
|-
|Stanford
|Stanford
|ford.com
|Stealing lunches from startups
|-
|Stanford
|Yes Please
|@twitter
|Are you Stanford?
|-
|
|Applying
|For a job
|I would like to work at you
|-
|St.Olaf
|Me olaf
|You Helga
|Hunting wooly mammoths
|-
|Ohio State
|Oh!
|IO
|O HAI O
|-
|
|FOLLOWBACK
|TOTALLY.EDU.US
|CONVENIENT US DOMAIN REDIRECTS
|-
|
|Mancher
|Outlook
|Made a collage out of macaroni
|-
|Stanford
|Yes Please
|ford.com
|Are you Stanford?
|-
|Michigan
|ANN
|SOUTH DETROIT
|HUNT LIKE A WOLVERINE
|-
|
|christopher
|POBox 12532
|p.s. ill find my frog
|-
|Oxford
|Bond, James
|Righto
|We're better than Cambridge
|-
|
|Which one
|Forget it
|Riding the L all night long
|-
|Kit
|Kat
|Oh dear
|Something something sleep
|-
|Google
|My G+ handle?
|Any
|I'm feeling lucky
|-
|UIC
|Which one
|Forget it
|Riding the L all night long
|-
|
|MY JOB NOW
|@
|SAVE DOCUMENT AND SEND
|}

===Sixth Panel===
{| class="wikitable table-padding"
|-
|At [company], you'll work at a scale you won't find anywhere else
|-
|Explore the depths of expensive and undocumented tools!
|-
|At Apple, we believe in pushing the boundary of perfection.
|-
|At Microsoft, you just need to relax and embrace the machine 
|-
|Yahoo management aren't just suits. We code too!
|-
|At [company], you'll have the opportinity to work on cutting-edge projects.
|-
|At Amazon, you'll be shaving the most cutting-edge of yaks.
|-
|You get to bid first on any auction, and use other experimental tools!
|-
|At QUALCOMM, Device driver code quality is job #1
|-
|Make use of our powerful in-house game creation tools.
|-
|We're even working on some experimental biotechnology
|}

===Seventh Panel===
{| class="wikitable table-padding"
|-
|[[File:externality-dog1.png]]
|-
|[[File:externality-dog2.png]]
|-
|[[File:externality-dog3.png]]
|-
|[[File:externality-dog4.png]]
|-
|[[File:externality-dog5.png]]
|-
|[[File:externality-dog6.png]]
|-
|[[File:externality-dog7.png]]
|-
|[[File:externality-dog8.png]]
|-
|[[File:externality-dog9.png]]
|-
|[[File:externality-dog10.png]]
|-
|[[File:externality-dog11.png]]
|-
|[[File:externality-dog12.png]]
|-
|[[File:externality-dog13.png]]
|-
|[[File:externality-dog14.png]]
|-
|[[File:externality-dog15.png]]
|-
|[[File:externality-dog16.png]]
|-
|[[File:externality-dog17.png]]
|-
|[[File:externality-dog18.png]]
|-
|[[File:externality-dog19.png]]
|-
|[[File:externality-dog20.png]]
|}

==Title Text==
The title text documents the different sources of data in the comic. The different title texts are:

{| class="wikitable table-padding"
|-
!Comic region
!Title text
|-
|Most of the comic, during the competition.||Mouse over words and things to see where they come from.
|-
|Most of the comic, after the competition ended||This comic went up on April 1st, and the panels changed throughout the day in response to readers doing things like breaking hashes, edited a rapidly-shuffling set of target Wikipedia articles, and donating to Wikimedia Foundation. (The vandalism is over now and CMU won the hashing contest.)
|-
|Most of the text in the first panel.||Happy April 1st, Everyone!
|-
|Fifth panel.||[University] has the third best hash. See the full standings at http://almamater.xkcd.com/best.csv
|-
|Last panel.||The dog gains a pound for every $10 donated to the wikimedia foundation via this link. Currently at [amount donated]
|}

==Transcript==
:[The comic is dynamically generated from multiple sources.]

:[First panel [[1193: Externalities#First Panel|transcript varies.]]]

:[Second panel [[1193: Externalities#Second Panel|transcript varies.]]]

:[Third panel [[1193: Externalities#Third Panel|transcript varies.]]]
:[Ponytail riding on a roomba.]

:[Fourth panel [[1193: Externalities#Fourth Panel|transcript varies.]]]
:[A group of people waiting outside a door. One of them is holding a large net.]

:Or [university] graduates, provided any of them manage to fill out the application correctly.
:Name: [random]
:Email: [Third place university]

:[Sixth panel [[1193: Externalities#Sixth Panel|transcript varies.]]]
:Cueball: What does "make dog" do?
:Off-panel: Experimental dog generator. Don't click on it; the default size isn't set, so-
:'''*click*'''

:''KZZZT''
:BIP
:Off-screen: Uh-oh.

:[Last panel's [[1193: Externalities#Seventh Panel|transcript varies.]]]

{{comic discussion}}
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairy]]
[[Category:Dynamic comics]]

1133: Up Goer Five

2012-11-28T02:42:41Z

70.79.36.61:

{{comic
| number = 1133
| date = November 12, 2012
| title = Up Goer Five
| image = up goer five.png
| imagesize =
| titletext = Another thing that is a bad problem is if you're flying up to space and the parts start to fall off your space car in the wrong order. If that happens, it means you won't go to space today, or maybe ever.
}}

==Explanation==
Most of the jargon used in rocket science is not among the most commonly used words in everyday life. This comic is a commentary on the absurdity of boiling down technical explanations for lay people.

This comic is a diagram of the {{w|Saturn V}} rocket, "Saturn" isn't a very common word apparently, and neither is rocket, so [[Randall]] decided to use "Up Goer" which is a fair approximation of a craft designed to lift a payload from the earth to space. The Saturn V vehicle, which was in use by {{w|NASA}} from 1967 to 1972, is the vehicle as a whole. The engines of the Saturn V (the part that makes it go up) were divided into three stages. The first stage ({{w|S-IC}}) had five {{w|F-1 (rocket engine|F-1}} engines which burned {{w|RP-1|refined kerosene}} mixed with oxygen as its fuel. That stage burned for 2 minutes 48 seconds and pushed the whole thing up about 61 kilometers (~38 miles) into the sky. After it fell away the {{w|S-II}} stage was activated. It used 5 {{w|J-2 (rocket engine)|J-2}} engines in the same configuration as the F-1s, and burned {{w|liquid hydrogen}} mixed with {{w|liquid oxygen}} for 6 minutes 35 seconds pushing the astronauts up to 184 kilometers (114.5 miles). The third stage ({{w|S-IVB}}) was a single J-2 engine burning liquid hydrogen and liquid oxygen. This stage was used in two parts, the first was to put the spacecraft into a stable orbit around Earth to perform a systems check and make sure the craft will be safe for going to the moon. This would usually take three orbits around Earth. As they came around the Earth they would burn the second part of the fuel, which is called a {{w|trans-lunar injection}} which put them on course for the moon. The first burn took 2 minutes 45 seconds, which put them in orbit 185 kilometers (115 miles) high.

It was first used as the launch vehicle for the {{w|Apollo 4}} mission, and it was used as the launch vehicle for most of the subsequent {{w|Apollo mission}}s (the exceptions being Apollo 7, Skylab 2-4, and the Apollo-Soyuz Test Project missions, which were launched using the smaller {{w|Saturn IB}} launch vehicle). One of the last missions of this design was the unmanned launch of {{w|Skylab}}, the U.S.'s first space station; for this payloader configuration, the Saturn V launch vehicle was officially designated the {{w|Saturn INT-21}}.

The Service Module (SM) Oxygen tanks, have a note that "This part had a ''VERY'' big problem once". This is a reference to the {{w|Apollo 13}} mission. 55 hours after launch, mission control requested the oxygen tanks contents be stirred to get an accurate reading of its contents. There was {{w|Apollo 13#Oxygen tank incident|a large bang}}, and power fluctuated throughout the craft. NASA had to scramble to ensure the safe return of the astronauts, needless to say, the moon landing for that mission was canceled.

The {{w|Hindenburg disaster}} is referenced in the text "The kind of air that once burned a big sky bag and people died and someone said "oh, the [humans]!". The term "big sky bag" is used as the closest approximation of {{w|zeppelin}} which is a big bag filled with a lighter-than-air gas which makes the whole contraption float. The {{w|LZ 129 Hindenburg|Hindenburg}} on the day of the disaster was filled with {{w|hydrogen}}, despite being initially designed for use with {{w|helium}}. Helium is much less prone to catching fire, but was unavailable due to a US export ban on the element. The risks seemed acceptable at the time because the Germans had a history of flying hydrogen-based passenger airships. The original quote is "Oh, the humanity!" [http://www.youtube.com/watch?v=F54rqDh2mWA] (skip to 0:47 for the quote).

The bottom tank, which [[Randall]] describes as "...full of that stuff they burned in lights before houses had power." is highly refined kerosene, called {{w|RP-1}}, it is similar to jet fuel, burns well and is not likely to explode; unlike {{w|liquid hydrogen}}, which is much more likely to explode.

==Transcript==
:US Space Team's Up Goer Five
:The only flying space car that's taken anyone to another world (explained using only the ten hundred words people use the most often)
:[A list of Saturn-V parts, top to bottom, with their "Up Goer" description follows]
:[Launch Escape System (LES)]: Thing to help people escape really fast if there's a problem and everything is on fire so they decide not to go to space
::[LES side nozzle]: Thing to control which direction the escaping people go
::[LES fuel]: Stuff to burn to make the box with the people in it escape ''really fast''
::[LES bottom nozzles]: Place where fire comes out to help them escape
:[Apollo spacecraft]
::[Command Module (CM)]: Part that flies around the other world and comes back home with the people in it and fall in the water.
:::[CM capsule parts]: People box, door, chairs
::[Service Module (SM)]: Part that goes along to give people air, water, computers and stuff. It comes back home with them but burns up without landing.
:::[SM oxygen tanks]: Cold air for burning (and breathing). This part had a ''VERY'' big problem once.
::[Lunar Module (LM)]: Part that flies down to the other world with two people inside
:::[LM descent stage]: Part that stays on the other world (it's still there)
:::[LM feet]: Feet that go on the ground of the other world
:[Instrument Unit]: Ring holding most of the computers
:[S-IVB third stage]: Part that falls off third (this part flew away from our world into space and hit the world we were going toward)
::[Fuel tanks]: Wet and ''very'' cold
:::[Liquid hydrogen (LH2) tank]: The kind of air that once burned a big sky bag and people died and someone said "Oh, the [humans]!" (used for burning)
:::[Liquid oxygen (LOX) tank]: The part of air you need to breathe, but not the other stuff (used for burning)
:::[Helium pressurizing tanks]: Things holding that kind of air that makes your voice funny (it's for filling up the space left when they take the cold air out to burn it.)
::[J-2 engine nozzle]: Fire comes out here
:[S-II second stage]: Part that falls off second
::[LH2 tank]: More sky bag air (for burning) (cold + wet)
::[LOX tank]: More breathing-type air (for burning) (cold + wet)
::[Tank-to-engine fuel lines]: Thing that brings in cold wet air to burn
::[J-2 engine nozzles (qty. 5)]: Fire comes out here
:[S-IC first stage]: Part that falls off first
::[LOX tank]: More breathing-type air (for burning) (cold + wet)
::[Helium pressurizing tank]: More funny voice air (for filling up space)
::[LOX fill line]: Opening for putting in cold wet air
::[RP-1 fuel tank]: This is full of that stuff they burned in lights before houses had power. It goes together with the cold air when it's time to start going up.
::[F-1 engine nozzles (qty. 5)]: Lots of fire comes out here.
:[Bottom of spacecraft]: This end should point toward the ground if you want to go to space. If it starts pointing toward space you are having a bad problem and you will not go to space today.

==External Links==
*[http://history.msfc.nasa.gov/saturn_apollo/documents/First_Stage.pdf First Stage Fact Sheet]
*[http://history.msfc.nasa.gov/saturn_apollo/documents/Second_Stage.pdf Second Stage Fact Sheet]
*[http://history.msfc.nasa.gov/saturn_apollo/documents/Third_Stage.pdf Third Stage Fact Sheet]
*[http://splasho.com/upgoer5/ The Up-Goer Five Text Editor]

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Charts]]
[[Category:Language]]
[[Category:Physics]]