explain xkcd - User contributions [en]

Talk:1075

2022-11-23T23:45:18Z

162.158.74.44:

Very smooth redirection to actual article! —[[User:While False|While False]] ([[User:While False/explain xkcd museum|'''museum''']] | [[User talk:While False|talk]] | [[special:Contributions/While_False|contributions]] | [[special:Log/While_False|logs]] | [[Special:UserRights/While_False|rights]] | [https://www.explainxkcd.com/wiki/index.php?title=User:While_False&printable=yes printable version] | [https://www.explainxkcd.com/wiki/index.php?title=User:While_False&action=info page information] | [https://www.explainxkcd.com/wiki/index.php/Special:WhatLinksHere/User:While_False what links there] | [https://www.explainxkcd.com/wiki/index.php?title=Special:RecentChangesLinked&days=30&from=&target=User%3AWhile_False related changes] | [https://www.google.com Google search] | current time: {{CURRENTTIME}}) 18:16, 23 November 2022 (UTC)
:This is my obligatary "Why did you even create this page/make this comment?" message... To which I expect no valid answer, but have a nice day anyway... [[Special:Contributions/162.158.74.44|162.158.74.44]] 23:45, 23 November 2022 (UTC)

1771: It Was I

2016-12-12T17:29:49Z

162.158.74.44: Italics plz.

{{comic
| number = 1771
| date = December 12, 2016
| title = It Was I
| image = it_was_i.png
| titletext = It me, your father.
}}

==Explanation==
We see {{w|Palpatine}}, {{w|Luke Skywalker}} (drawn as an xkcd character) and {{w|Darth Vader}}. The comic starts with a scene from ''{{w|Return of the Jedi}}'', but the tension deflates when the conversation suddenly veers into one of proper grammar.

Initially Palpatine begins saying "It was I who..." In traditional {{w|linguistic prescriptivism|prescriptive}} English grammar, the verb "to be" is a {{w|Indo-European copula|copula}}. This means that in a sentence of the form "A is B", both A ''and'' B are treated like the subject of the sentence. In most Indo-European languages, subjects use the {{w|nominative case}} - although the case system in English has almost died out, ''I'', ''he'', ''she'' and ''we'' are fossils of nominative case pronouns - and the object of the sentence uses the {{w|accusative case}} - ''me'', ''him'', ''her'', ''us''.

This rule is still strong in languages like German, where speakers still use cases and therefore are familiar with how they work. However, English's case system is so weak that most people only know the rule "''I'' goes before a verb, ''me'' comes after a verb or preposition". This gives the correct result in sentences like "It saw me". By extension, speakers therefore often say "It was me" ([https://www.youtube.com/watch?v=cNgxyL5zEAk here's a famous example from Vince McMahon]) - logical, but not true to the traditional rules. Luke thinks that there's nothing wrong with this modern sense, as he is a {{w|linguistic descriptivism|descriptivist}}.

However, as Darth Vader points out, "It was I" is not incorrect, and it is a {{w|set phrase}} with a good archaic ring to it suitable for a dramatic revelation from an Emperor. Vader and the Emperor using English archaisms has canon basis in ''Star Wars'', with Vader asking "What is thy bidding, my master?" in ''The Empire Strikes Back''.

Palpatine finally decides to take a third option, and uses "[http://www.papermag.com/it-me-you-and-everyone-we-know-a-look-at-the-webs-most-ambiguous-meme-1427655235.html it me]", a popular meme on Twitter in 2016. Darth Vader, out of embarrassment, begs him not to talk like that again.

One of [[Randall]]'s themes is that grammar pedants apply rules to correct other people long after those rules have fallen out of actual usage. Luke is here being an anti-grammar-pedant, asking the Emperor to disapply the rule. The joke is that he is concentrating on the linguistics of what he is saying, rather than the actual significance of it. See [[890: Etymology]] for another instance of Luke failing to notice semantics.

The title text runs with the joke in the final panel, applying the same meme to Darth Vader's iconic quote "No, I am your father." It could be said that such a phrasing robs the moment of all gravitas, but then again, Yoda managed to coin a phrase like "Do or do not; there is no try", and still be taken seriously.

==Transcript==
{{incomplete transcript}}

[Emperor Palpatine, Luke Skywalker, and Darth Vader in throne room]

Emperor: It was I who allowed the alliance to know the location of the shield generator.

Luke: You mean "It was ''me''." You're following an archaic grammar rule.

Emperor: It was ''me'' who allowed the-

Vader: No, my master, an archaic tone is appropriate here. The sentence sounds-

Emperor: It was ''I'' who allowed-

Luke: Come on, the accusative case is fine. Nominative pronouns are-

Emperor: '''''It me'''''

Emperor: '''''I allowed it'''''

Vader: My master,

Vader: Please never say that again.

{{comic discussion}}

[[Category:Star Wars]]
[[Category:Language]]

Talk:1768: Settling

2016-12-06T13:49:28Z

162.158.74.44:

I'm not sure it's just about places where you live(d). This scorecard is applicable to relationships of one person and surely other things as well. {{unsigned ip|162.158.91.218}}
:Nobody said anything about that [[User:Jacky720|Jacky720]] ([[User talk:Jacky720|talk]]) 17:36, 5 December 2016 (UTC)
And of course the title text is about time travel or that groundhog-day-thing with Bill Murray. {{unsigned ip|162.158.91.218}}

I think people also may stick with what they've got due to an inability to appreciate that the resulting unhappiness and even chaos is temporary. We are prone to thinking our present state of mind is permanent. [[User:ExternalMonolog|ExternalMonolog]] ([[User talk:ExternalMonolog|talk]]) 20:32, 5 December 2016 (UTC)

There's this recurring theme in xkcd of the possibility and choice to pursue the unknown, with other such comics including [[59]], [[137]], [[267]], and [[706]]. Should we have a category for it? [[User talk:AgentMuffin|~AgentMuffin]]

The obvious question: is Randall really happy writing XKCD?[[Special:Contributions/199.27.128.98|199.27.128.98]] 01:37, 6 December 2016 (UTC)
:Too Meta... (But a good question nonetheless heh, he has been doing it a long time though, and continues What If? As well, which it seems he enjoys doing)
--[[Special:Contributions/108.162.242.101|108.162.242.101]] 03:57, 6 December 2016 (UTC)

The title text plus the use of "Should've" and "shouldn't've" imply that he made a different choice. Perhaps the ratio of tallies in the comic is merely a result of the ratio of how often he is prone to staying vs prone to leaving situations. If the implication is true, we need the number of times that he's stayed when he should've stayed and left when he should've left in order to make any statistically based recommendations. [[User:NotLock|NotLock]] ([[User talk:NotLock|talk]]) 04:31, 6 December 2016 (UTC)

To my mind this is about always making the wrong decision in retrospective. He should have left sooner or he should have stayed means that in both cases he left. But there was something better to do either way.Either he made the wrong decision and should have stayed or he made the decision to late. So in either case he did something wrong.[[Special:Contributions/162.158.114.228|162.158.114.228]] 08:32, 6 December 2016 (UTC)

Does anyone else think Randall is hinting that he wants to quit XKCD? ~~Don

Talk:1768: Settling

2016-12-06T13:48:08Z

162.158.74.44:

1761: Blame

2016-11-18T13:24:17Z

162.158.74.44:

{{comic
| number = 1761
| date = November 18, 2016
| title = Blame
| image = blame.png
| titletext = I bet if I yell at my scared friends I will feel better.
}}

==Explanation==

{{incomplete|There needs to be more}}

Cueball states that he feels sad and links it with his observation that bad things are happening. Sadness is a normal human reaction to perceived bad events. (Other emotions that might be felt at such times include anger and guilt.)

He then reasons that it must be someone's fault. If the "bad things" in question are not natural calamities or accidents, it is usually logical to surmise that someone is responsible for them taking place.

After some thinking, he has an idea. Ideas are usually the result of thinking, although it might not always be conscious thinking like Cueball is doing.

He then blames his friends on Facebook, an online website that helps people communicate with other people through their computers and handheld electronic devices. While they could be possible reason for bad events(for example if the bad event was nobody wishing him a happy birthday or someone posting compromising pictures)his friends would not be a likely source for bad events extending beyond a personal or local scope. Most people have a few hundred (or thousand) friends (or "friends") on Facebook, most of whom do not have enough influence to cause bad events on a national or global level.{{Citation needed}}

This is probably a reference to people ranting on social media sites (like Facebook) about various things which are blamed on certain people (or sometimes everyone), but the person doing the ranting never thinks that the problem might be with themselves.

It probably also a reference to how an individual's Facebook news feed has probably been inundated by political posts due to the results of the 2016 election.

===Title text===

The title text refers to people venting, usually in all caps and with exclamation points. Usually users do this when they are mad. The (humorous) assumption here is that one will feel better after doing so. While some amount of venting might help to relieve immediate stress caused by bad events, alienating people you know by blaming them for bad events usually causes more stress in the long run.

==Transcript==
:Cueball: I feel sad.
:Bad things are happening.
:They must be someone's fault.
:But whose?
:[A light bulb, indicating he has an idea]
:My friends on Facebook.

{{comic discussion}}

115: Meerkat

2016-09-25T05:38:40Z

162.158.74.44:

{{comic
| number = 115
| date = June 14, 2006
| title = Meerkat
| image = meerkat.jpg
| titletext = Gorilla, yes. Adorable golden retriever, yes. But it says nothing about meerkats.
}}

==Explanation==
The situation is a reference to the [http://tvtropes.org/pmwiki/pmwiki.php/Main/AnimalAthleteLoophole animal athlete loophole] trope, where an animal joins a failing sports team and saves the day. The other team (i.e. the bad guys) does not like it, but since there is not a specific rule against it, it has to be allowed.

In this particular situation, Randall uses both an animal ({{w|Meerkat}}) and sport ({{w|Rugby football|rugby}}) that haven't been used in an animal sports movie before.

The title text mentions an "adorable golden retriever", a direct reference to the most famous animal athlete film ''Air Bud''.

This concept was revisited in [[1552: Rulebook]].

==Transcript==
:[A Meerkat wearing a helmet and jersey, and two guys in the background supposedly on a rugby field.]
:You have to admit--there's no rule on the books saying a Meerkat can't play rugby.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Sport]]
[[Category:Animals]]

1737: Datacenter Scale

2016-09-23T14:42:15Z

162.158.74.44:

{{comic
| number = 1737
| date = September 23, 2016
| title = Datacenter Scale
| image = datacenter_scale.png
| titletext = Asimov's Cosmic AC was created by linking all datacenters through hyperspace, which explains a lot. It didn't reverse entropy--it just discarded the universe when it reached end-of-life and ordered a new one.
}}
==Explanation==
{{incomplete|The paragraph explaining the final panel needs a grammar check.}}

{{w|RAID}} ("redundant array of independent disks") is a technology that splits data across several hard-drives as if they were one. RAID comes in several levels for different uses, but one of the big applications of RAID is creating mirrored hard disks that back each other up. If one disk drive in a RAID array fails, no data is lost.

However, RAID is complicated to configure, so you don't want to be constantly setting it up. An alternative technique for data centers is therefore to simply send the data to several servers at once. This makes maintenance easier, but without RAID, one hard disk crash basically breaks the server. However, this is what the woman with a bun's data center is doing since their scale is so large that fixing individual servers do not make sense, and instead of fixing the drive they throw away the machine.

From here, the comic starts to exaggerate. Nowadays, servers can be made extremely small ("{{w|Blade server}}s") and dozens of servers can be attached to one {{w|19-inch rack}} in a data center. Rather than going to the effort of unplugging and unscrewing one blade from the rack, when a blade fails at [[Cueball]]'s data center they just throw away the rack, and [[Ponytail]] agrees and kinda mock the woman with a bun for replacing one server.

[[Hairy]]'s goes one step further - they have so many servers that they would constantly have to be throwing away and replacing racks, so instead they just build a new room when one rack fails. This would be currently possible with small modular data centers that are built in shipping containers for easy transport and can be linked together to expand capacity. Here the cargo-container "room" with the failure would be quickly swapped with a fresh one. Cueball adds "like Google!" - [[Randall]] previously mentioned {{w|Google|Google's}} approach to hard drive failures in the [[what if?]] ''{{what if|63|Google's Datacenters on Punch Cards}}''. Back in [http://static.googleusercontent.com/media/research.google.com/de//archive/disk_failures.pdf 2007] they had one failure every few minutes - that might have increased hugely since then.

Finally [[Megan]] appears and her company of course breaks the scale of silliness in exaggeration. She says that they don't have any fire extinguishers (neither {{w|Fire sprinkler system|regular sprinklers}} nor the {{w|Gaseous fire suppression|inert gas systems}} that flood the room with gases like argon which force out oxygen and stop fires - these are better for computers than traditional water or powder systems, but are lethal to people trapped in the rooms!). Rather, they just rope the center off let, thus letting the data center burn down. Then they simply move a town over and build a new one. This may indicate they are so big that the entire town will burn down if their center catches fire, for else they did not have to skip town. Alternatively, they just leave the center burning and this may cause problems in that town, so they simply flee the premises.

Most big internet companies do have multiple redundant data centers around the world, in order to increase speeds for users in different countries, but Megan's idea would be very expensive, increase in {{w|Latency (engineering)|latency}} and possibly also kill people, either in their company or other people in the town and since they do not try to turn out the fire, at least cause severe destruction of properties, not only their own.

Still Hairy thinks that it makes sense, whereas Cueball wonders what difference the roping off does. This could again be a reference to the fact that they just let the buildings burn without bothering about the local consequences, and the next step is just one more step towards the extreme of the title text.

This comic references how, as data requirements expand, companies rarely use more specific, but time costly choices when working with data centers, and use more expensive but faster solutions. While this comic takes this to the extreme, with whole buildings being destroyed for simple flaws, the concept is not as far fetched as it seems if "thrown out" is taken to include being sold to equipment refurbishers. It could indeed be cost effective for a large data services provider to resell racks or even whole data center modules at some significant fraction of their "as new" price as opposed expending the time and effort to attempt a repair. The equipment refurbisher would then rely on a {{w|competitive advantage|cost advantage}} like cheaper labor to repair the flaw and sell it back to Google or another company with less demanding requirements. Equipment rental firms already operate on this model and with the added incentive customers preferring to rent newer models, this means that the equipment is often ''preemptively'' replaced before failures even occur.

The title text refers to {{w|Isaac Asimov}}'s science-fiction novella "{{w|The Last Question}}", where humanity asks, at different stages of its spatial and technological development, the same question to increasingly advanced computers: "How can the net amount of {{w|entropy}} of the universe be massively decreased?". At each point, the computer's answer is that it does not yet have enough data for a meaningful answer. Ultimately, the computers are all linked through hyperspace, outside the physical boundaries of the universe, and make up a single computing entity named AC which keeps pondering the question even as the {{w|heat death of the universe}} occurs and time and space cease to exist. When AC finally discovers the answer, since there is nobody left to report it to, it decides to demonstrate it and says "{{w|Let there be light|LET THERE BE LIGHT!}}", which are the first words said by God during the Creation, according to the {{w|Book of Genesis}}. Here, the title text implies that, as the universe died, AC no longer had a use for it as a physical support and, taking the comic's logic to the next extreme, chose to discard it and get a brand-new one instead of bothering to "fix" it by reversing its entropy.

==Transcript==
:[Zoom in on a woman with a bun holding her hand palm up in front of her taking to people off-panel right.]
:Woman with a bun: RAID controllers don't make sense at our scale; everything is redundant at higher levels. When a drive fails, we just throw away the whole machine.

:[In this frame-less panel it is revealed that the woman with a bun talked to Cueball and Ponytail who is looking her way.]
:Cueball: Machine? We throw away whole racks at a time.
:Ponytail: Yeah, who replaces ''one server''?

:[Hairy has appeared from the left and holds one hand palm up towards the other three where also the woman with a bun has turned towards him.]
:Hairy: We just replace whole rooms at once. At our scale, messing with racks isn't economical.
:Woman with a bun: Wow.
:Cueball: Like Google!

:[Megan walks in from the left, and everyone including Hairy now looks towards her. Cueball has taken a hand up to his chin. The replies to Megan are written with clearly smaller font.]
:Megan: We don't have sprinklers or inert gas systems. When a datacenter catches fire, we just rope it off and rebuild one town over.
:Hairy: Makes sense.
:Cueball: I wonder if the rope is really necessary.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Megan]]
[[Category:Computers]]
[[Category:Fiction]]

1732: Earth Temperature Timeline

2016-09-14T22:58:56Z

162.158.74.44:

{{comic
| number = 1732
| date = September 12, 2016
| title = Earth Temperature Timeline
| before = [[#Explanation|↓ Skip to explanation ↓]]
| image = earth_temperature_timeline.png
| titletext = [After setting your car on fire] Listen, your car's temperature has changed before.
}}

==Explanation==
{{TOC}}
{{incomplete|[[#Table of all elements|Table for explanations]] now ready to be filled out. Please remove this tag only when everything is explained.}}
In the past 100 years, human action produced lots of {{w|CO₂ emissions}}, which have caused a rise in average global temperature through the {{w|greenhouse effect}}. This is called {{w|global warming}} and is part of a {{w|climate change}}, a subject that has become a [[:Category:Climate change|recurrent subject]] on xkcd. There are still many people who claim that this is not happening, or at least that it is not caused by any human actions, called "climate change deniers". One argument of theirs is that global warming is happening for natural causes, summarized with the phrase "temperature has changed before". This comic is a direct, but much more thorough, follow up on the previous global warming comic: [[1379: 4.5 Degrees]].

This comic shows that while temperature changes have indeed occurred before, the speed of the current temperature rise is much, much faster than those seen (actually: estimated) in the previous thousands of years. It seemed to touch on something in peoples consciousness, because it became so popular that [[Randall]] [[#Popularity_of_comic|postponed the release]] of his next comic to keep this one on the front page one day longer.

This comic is a [[:Category:Timelines|timeline]] on how the temperature has changed since 20,000 BCE to the present day and extrapolated 84 years on from present day of the release of the comic (2016) to 2100 depending on the choice of actions to stop CO₂ emission that is taken now or never. It is meant to contrast the slow-paced natural changes with the rapid temperature rise in the recent years. The effect is achieved by forcing the reader to scroll endlessly through slow, building-up changes and then face them with an almost instantaneous, quick rise towards the end. The temperature curve is a dotted line most of the time, but from about 1850 to present day (2016) the measurement data is good enough to let the curve become a solid line indicating that this is not an estimate. Before 1850 the temperature is an estimate based on the [[#Sources|sources]] given. And likewise into the future the curve is also dotted as this is predictions. And here there are even three possible outcomes depending on how seriously politicians and other influential people (and the population of Earth) take knowledge (and comics) like this.

Below in the [[#Table of all elements|table]] each entry will be noted and explained (in time). This is one of the comics where Randall cites his [[#Sources|sources]] like he did for one of his other very large comics [[980: Money]].

The title text compares the saying that "the temperature has changed before" comparing temperature changes over thousands of years to the rapid global warming over the last century with saying that the "small" changes to the temperature a car experiences over the years of normal usage should not make you worried over the rapid temperature increase that happens when someone sets your car on fire. A related joke was used recently in [[1693: Oxidation]].

===Table of all elements===
*Here is table (to be filled out) of all elements with explanations including reading of temperature and year for each event from the curve.
*Table ready for use:
**The year group is just an easy way to find the section.
**The actual year of an event should be read off more precisely on the chart.
***Suggestion for doing this:
***Top part of element
***Central part of element
***Other?
**Element is a description mainly taken from the transcript. Feel free to remove redundant information, but the guess was that getting the table ready was the most important feature for getting the explanation started.
**T (°C) should be read of for the curve for every element.
**Explanation explains itself.
{| class="wikitable"
!Year group
!Element
!Year
!T (°C)
!Explanation
|-
| rowspan="2"| 20000 BCE
| [An arrow goes from the dotted line to the central line at 0°C. In the middle of the line there is a temperature label:] 4.3°C At the start of our timeline, 22,000 years ago, Earth is 4°C colder than during the late 20th century. || 20000 BCE || -4.3 || The temperature at the beginning of the chart compared to the average from 1961-1990 that we compare temperatures with today.
|-

| {{w|Boston}} is buried under almost a mile of ice, and the {{w|glaciers}} reach as far south as {{w|New York City}}. [The Statue of Liberty is shown in front of a glacier front. A guy with a white {{w|knit cap}} is seen walking in a snowy landscape. The skyline of Boston is shown under a half a mile of ice.] || 19700 BCE || -4.3 || The Boston image is directly taken from [[1225: Ice Sheets]] about the ice age glacier coverage and the guy with the white knit cap could be the guy from [[1321: Cold]] also about global warming. It shows what a difference 4 degree in global temperature means (massive effect), as opposed to what four degree means on a daily weather wise scale (nothing!). [[Randall]] lives in Boston. It was also shown buried in ice in [[1379: 4.5 Degrees]]. Knit caps have only been used a few times in xkcd, most prominently on [[1350:_Lorenz#Knit_Cap_Girl|Knit Cap Girl]] in [[1350: Lorenz]], see her section for more details.

|-
| rowspan="3"| 19500 BCE
| But the world is about to warm up. || || || The warming process actually takes thousands of years, but this is quite rapid on a geological scale.
|-
| By this time, humans have already spread across Africa, Eurasia, and Australia. || || ||
|-
| They’ve created painting, pottery, rope, and bows and arrows, but haven’t developed writing or farming. || || ||

|-
| rowspan="2"| 19000 BCE
| Changes in the Earth’s orbit mean that more sunlight reaches the polar ice… || || ||{{w|Milankovitch cycles}} are repeated climate variations on a timescale of tens of millennia.
|-
| [A line chart with a labeled Y-axis "Summer sun W/m2 at 60°N" with three labeled ticks ranging from 450-550. The curve starts up and then goes down five times and up four times ending down. There is one plateau towards the end compared to the rest of the curve where the ups and downs are quite alike.] || || ||

|-
| rowspan="1"| 18500 BCE
| [A map of the world. At the top is a light gray area covering North America, Greenland and northern Europe and most of the northern part of Russia. A similar gray area covers Antarctica. The gray areas are labeled as ice.] || || ||

|-
| rowspan="1"| 18000 BCE
| …And the ice sheets start to melt. || || ||

|-
| rowspan="1"| 17500 BCE
| Temperatures have been creeping upward, but around this point, CO2 levels start to climb…|| || ||

|-
| rowspan="1"| 17000 BCE
| …And then the warming speeds up. || || ||Again, sarcasm about the slow speed of natural climate change compared to modern anthropogenic warming.

|-
| rowspan="1"| 16500 BCE
| [Cueball is standing with a spear just the right of the graph talking to a rabbit.] Cueball: Still pretty cold. || || ||

|-
| rowspan="2"| 16000 BCE
| [Megan points to the graph to the right of her and between her and Ponytail standing on the other side. Mean is the first drawing on the left side of the dotted curve, which has hardly moved since the beginning, only to just on the other side of 4°C.] || || ||
|-
| [In the right part of the chart is an explanation of the data. Below the first two lines there are four drawings each showing possible temperature swings in reality compared to the smoothed data that represents the dotted curve of the entire chart. The dotted curve is shown in all four drawings and a thin line is shown running along it but with much more fluctuation left and right on the first two, a large spike right on the third and a large bump way right on the fourth. Above these there are two labels. The first labels is inside a bracket that covers the first three, and the last label is for the last drawing. Below is a list of sources.] Limits of this data: Short warming or cooling spikes might be “smoothed out” by these reconstructions but only if they’re small or brief enough. Possible Unlikely Reconstructions are from Shakun (2012) and Marcott (2013), scaled to Annan + Hargreaves (2013) estimate for the last glacial period. || || ||

|-
| rowspan="1"| 15500 BCE
| In what is now France, humans paint murals on the walls of the Lascaux caves [Hairy paints three animals, two with horns, and two humans, Cueball holding hand with Hairy who has a spear. On the other side of the central line Megan writes three letters, the last of which is reversed:] NIИ || || || A reference to the industrial techno band {{w|Nine Inch Nails}}.

|-
| rowspan="1"| 15000 BCE
| Ice sheets around Alaska shrink, exposing a land bridge between Asia and North America [From around the bottom if this section and down to 11500 BCE the dotted curve moved steadily to the right towards warmed temperature peaking close to -1.5°C. Before this the temperature had not moved much away from that at the start.] || || ||

|-
| rowspan="1"| 14500 BCE
| [Cueball walks right looking back at the graph behind him. Megan walks in front of him pointing further right.] | Cueball: Cool. || || ||

|-
| rowspan="2"| 14000 BCE
| The edge of the ice withdraws from New York City and retreats North. || || ||
|-
| [A large glacier front speaks in a speech bubble with an arrow pointing at it. Behind is there are four peaks in the horizon and in front of it three small melting pools and some rocks on the ground.] Glacier: ''That’s it! I’m moving to Canada!'' || || || When US citizens are unhappy with changes in their country, they sometimes say they will move to Canada in protest.

|-
| rowspan="2"| 13500 BCE
| Humans domesticate dogs (Date uncertain, may be much earlier) || || ||
|-
|| [Megan and Cueball is watching a wolf looking at them.] Megan: Okay, you can live in our homes and we’ll feed you, but we’ll still get mad if you poop on the floor. Wolf: Deal. Cueball: And we get to breed you to be tiny and dress you in little costumes. Wolf: …Wait. || || || See {{w|Origin of the domestic dog}}. They are often bred for size and occasionally made to wear clothing.

|-
| rowspan="2"| 13000 BCE
| {{w|Woolly Rhino}} goes extinct || || ||
|-
| Oregon is scoured by huge floods as glacial dams burst and lakes of meltwater flow to the sea || || || See {{w|Missoula Floods}}

|-
| rowspan="1"| 12500 BCE
| Ice sheets withdraw from Chicago || || ||

|-
| rowspan="1"| 12000 BCE
| Humans settle Abu Hureyra in Syria || || ||

|-
| rowspan="1"| 11500 BCE
| [An arrow on the left side of the dotted curve is pointing down along the dotted curve and to the left indicate temperature is declining again, meaning the dotted curve now moves left to colder temperatures. This only continues until 10500 BCE. It is only the second time something is noted on the left side after Megan at 16000 BCE] Temperatures start to decline, mainly in the Northern hemisphere This may be caused by changes in ocean circulation due to the floods of cold fresh meltwater flowing into the Atlantic as the North American ice sheet melts. This cooler period is called the {{w|Younger Dryas}} || || ||

|-
| rowspan="1"| 11000 BCE
| [This is the first text to the left of the dotted curve:] Humans reach Argentina || || ||

|-
| rowspan="2"| 10500 BCE
| [An arrow pointing down along the right side of the dotted curve and to the right indicate temperature is increasing again, meaning the dotted curve now moves right to hotter temperatures. This continues until 8000 BCE where it levels out just above 0°C.] Warming resumes || || ||
|-
| Human settlements at Jericho || || ||

|-
| rowspan="1"| 10000 BCE
| First development of farming || || ||

|-
| rowspan="2"| 9500 BCE
| Saber-toothed cat goes extinct || || ||
|-
| Horses disappear from North America || || ||

|-
| rowspan="4"| 9000 BCE
| | Last North American Pokémon go extinct [Cueball with a spear and Megan is looking up at this last “fact”.] Megan: That is not a real fact. || || || As prehistoric [[Megan]] states, this is not a real fact. Pokémon are still thriving throughout the entire world (see [[1705: Pokémon Go]]), and are most commonly found near [http://time.com/4443225/pokemon-go-affluent-white-neighborhoods-report/ affluent first world neighborhoods].
|-
| Temperatures reach modern levels || || ||
|-
| Rising seas cut off the land bridge between North America and Asia || || ||
|-
| {{w|Cattle}} domesticated || || ||

|-
| rowspan="2"| 8500 BCE
| Ice sheets retreat across the Canadian border || || ||
|-
| Temperatures start to level out slightly above 1961-1990 levels || || ||

|-
| rowspan="1"| 8000 BCE
| [The above sentence breaks over the 8000 BCE line. From here a maximum in temperature on the chart is reached at 0.5°C which will not be overtaken until 2000 CE. It stays almost constant here until 5000 BCE where a slight cooling begins.] || || ||

|-
| rowspan="2"| 7500 BCE
| This warm, stable period is called the {{w|Holocene Climate Optimum}} || || ||
|-
| {{w|Jiahu}} settled in China || || ||

|-
| rowspan="2"| 7000 BCE
| Final collapse of the North American ice sheet leads to rapid 2-4m sea level rise… || || ||
|-
| [A small arrow points down and left to the right of the dotted curve. There is a small decrease in temperature but it is very small and would have been missed without the arrow and label.] …And a period of cooling in the Northern hemisphere || || ||

|-
| rowspan="1"| 6500 BCE
| As seas rise to near their modern levels, Britain is cut off from mainland Europe || || ||

|-
| rowspan="1"| 6000 BCE
| Humans develop copper metalworking || || ||

|-
| rowspan="2"| 5500 BCE
| Massive volcanic eruption in Oregon creates crater lake || || ||
|-
| {{w|Gold}} metalworking || || ||

|-
| rowspan="2"| 5000 BCE
| {{w|Invention of the wheel}} || || ||
|-
| [To the right of the dotted curve is an arrow pointing down and slightly left. From here temperature decreases very slowly but steadily from 0.5°C until 1000 BCE where a stable plateau is reached around 0°C.] Earth begins to cool slowly mainly due to regular cycles in its orbit || || ||

|-
| rowspan="3"| 4500 BCE
| Proto-Indo-European language develops || || ||
|-
| [To the right of the curve Ponytail holds up a hand towards Cueball.] Ponytail: Let’s make out language heavily inflected, so future students have to memorize a zillion verb endings! Cueball: Okay! || || ||[[Ponytail]] refers to [[1709: Inflection]].
|-
| Permanent settlements in the fertile crescent || || ||

|-
| rowspan="2"| 4000 BCE
| Horses domesticated || || ||
|-
| {{w|Minoan civilization|Minoan}} culture arises on Crete || || ||

|-
| rowspan="4"| 3500 BCE
| {{w|Egyptian mummification}} || || ||
|-
| Rise of the Indus Valley civilization || || ||
|-
| Invention of writing in Sumer “prehistory” ends, “history” begins || || ||
|-
| Earliest human whose name we know (Pharaoh Iry-Hor in Egypt) || || ||

|-
| rowspan="5"| 3000 BCE
| {{w|Three Sovereigns and Five Emperors}} period in China || || ||
|-
| {{w|Gilgamesh}} || || ||
|-
| {{w|Imhotep}} || || ||
|-
| {{w|Maya civilization|Mayan}} culture emerges || || ||
|-
| {{w|Egyptian pyramids|Great Pyramid}} constructed || || ||

|-
| rowspan="3"| 2500 BCE
| {{w|Corded Ware culture}} in Europe || || ||
|-
| [To the left of the curve two rock musicians with long hair and electrical guitars are standing on either side of a small gate made of three slabs of stone, one on top of the other two standing stones.] Stonehenge completed || 2250 || || The drawing is a reference to the 1984 movie "This is Spinal Tap" (A documentary/parody featuring the fake metal band "Spinal Tap", http://www.imdb.com/title/tt0088258/), the musicians order a Stone Henge prop for the stage, which turns out to be too small (https://www.youtube.com/watch?v=qAXzzHM8zLw)
|-
| {{w|Chariots}} developed || || ||

|-
| rowspan="3"| 2000 BCE
| {{w|Alphabetic writing}} developed in Egypt || || ||
|-
| Last mammoths on a tiny Siberian island go extinct || || ||
|-
| {{w|Minoan eruption}} || || ||

|-
| rowspan="5"| 1500 BCE
| {{w|Iron smelting}} || || ||
|-
| {{w|Olmec}} civilization develops in Central America || || ||
|-
| [A Trojan horse with two Cueball-like guys in front and a third standing on its back. Its back is at three Cueball’s height and its head rises to the level of the Cueball on its back. It stands on a platform with four wheel on the visible side. There is text on the horse] Setting of the ''Iliad'' and the ''Odyssey'' Text on horse: Not a trap || || ||
|-
| Invasion of the Sea peoples* * A real thing || || ||
|-
| {{w|Polynesians}} explore the Pacific Ocean || || ||

|-
| rowspan="8"| 1000 BCE
| [From 1000 BBC to 1000 CE the temperature is stable and very close to 0°C.] || || ||
|-
| {{w|Solomon}} || || ||
|-
| {{w|Iliad}} and {{w|Odyssey}} composed || || ||
|-
| Rise of Greek city-states || || ||
|-
| {{w|Neo-Assyrian}} empire || || ||
|-
| First Olympics || || ||
|-
| {{w|Zapotec civilization|Zapotec}} writing in modern Mexico || || ||
|-
| {{w|Confucius}} || || ||

|-
| rowspan="10"| 500 BCE
| The stuff in the 300 (film)|movie ''300'', but regular speed and with more clothing || || ||
|-
| {{w|Buddha}} || || ||
|-
| {{w|Nazca Lines}} || || ||
|-
| {{w|Alexander the Great}} || || ||
|-
| {{w|Mayan hieroglyphics}} || || ||
|-
| {{w|Ashoka the Great}} || || ||
|-
| {{w|Paper}} invented || || ||
|-
| {{w|Asterix}} || || ||
|-
| {{w| Teotihuacan|Teotihuacán}} metropolis || || ||
|-
| {{w|Julius Caesar}} || || ||
|-

|-
| rowspan="8"|1 BCE 1 CE
| [At the year 0, there is instead two numbers for each of the two scales before (1 BCE) and after Christ (1 CE)] || || ||
|-
| {{w|Roman Empire}} || || ||
|-
| {{w|Jesus}} || || ||
|-
| [To the left and erupting volcano.] {{w|Pompeii}} || || ||
|-
| {{w|Three Kingdoms}} period || || ||
|-
| {{w|Gupta empire}} || || ||
|-
| Various groups take turns sacking Rome || || ||
|-
| {{w|Attila the Hun}} || || ||

|-
| rowspan="4"| 500 CE
| {{w|Muhammad}} || || ||
|-
| {{w|Tang Dynasty}} || || ||
|-
| [An arrow to the right of the dotted curve pointing down, takes a swing far out from the curve and then bends back again. The text label next to it breaks into the next 500 period. The dotted curve stays stable at 0°C along this arrow.] Medieval warm period in Europe and some northern regions (too regional to affect the global average much) || || ||
|-
| {{w|Leif Eriksson}} || || ||

|-
| rowspan="7"| 1000 CE
| [The dotted curve moves to the left towards lower temperature reaching a minimum around 1650 of about -0.6°C at the Little Ice Age.] || || ||
|-
| [To the left a drawing of a compass with needle pointing the black end towards north west. There are labels for the four main directions (N, S, E, W) and a label next to it:] Magnetic compass navigation || || ||
|-
| {{w|Ghengis Khan}} || || ||
|-
| {{w|Zheng He}}’s fleet explores Asia and Africa || || ||
|-
| {{w|Aztec Empire|Aztec Alliance}} || || ||
|-
| {{w|Printing press}} || || ||
|-
| {{w|Christopher Columbus|Columbus}} || || ||

|-
| rowspan="2"| 1500 CE
| {{w|European Renaissance}} || || ||
|-
| {{w|Shakespeare}} || || ||

|-
| rowspan="2"| 1600
| {{w|Isaac Newton|Newton}} || || ||
|-
| [To the right of the dotted curve there is an arrow pointing down that makes a swing in towards the curve and then back out again. At -0.6°C this is the coldest it has been since 9500 BCE. It is labeled:] ”{{w|Little Ice Age}}” || || || This was not a true geologic Ice Age, just a slightly chilly period.

|-
| rowspan="2"| 1700
| {{w|Steam engines}} || || ||
|-
| {{w|United States Declaration of Independence|Unites States Independence}} || || ||

|-
| rowspan="3"| 1800
| {{w|Industrial Revolution}} || || ||
|-
| {{w|Electrical telegraph|Telegraphs}} || || ||
|-
| [After this the dotted curve becomes solid.] || || || In the late 1800s, weather records became sufficiently accurate and widespread to greatly improve the precision of climate measurements.

|-
| rowspan="6"| 1900
| {{w|Airplanes}} || || ||
|-
| {{w|World Wars}} || || ||
|-
| [The solid line takes a step to the right close to 0°C. Over the rest of the 1900s it moves closer to 0°C crossing it before 2000 where it almost reaches the maximum temperature of 0.5 °C from earlier in 8000 BCE.] || || || This is what the previous 14000 pixels of comic has been leading up to. After a laborious 20 millennia of gradual and meandering climate change, it should be clear that a full degree of warming in a single century is unprecedented in human history, and very unlikely to be natural variation.
|-
| {{w|Fossil fuel}} CO2 emissions start rapidly increasing || || ||
|-
| {{w|Nuclear weapons}} || || || The Working Group on the 'Anthropocene' suggests dating the {{w|Anthropocene}} epoch from ~1950.
|-
| {{w|Internet}} || || ||

|-
| rowspan="2"| 2000
| {{w|Northwest Passage}} opens || || ||
|-
|[From here to present day the solid line increases rapidly and in 2016 present day is almost reaches 1°C, with about 0.8°C.] || || || [http://www.skepticalscience.com/argument.php?a=11&p=2 No, warming did not stop in 1998].

|-
| rowspan="3"| 2016
| | Present day || || ||
|-
| [From here the curve once again becomes dotted as this is the future. After one dot it splits in two and after the first two dots another split between them occurs forming three possible future dotted curves.] || || ||
|-
|The first curve bending down before the others, and thus to the right of the other two reaches about 1.2°C and then goes straight down and stops at the 2100 line. An arrow points to it from the left and a label is written partly before and the rest after the 2100 line to the left of the curve:] Best-case scenario assuming immediate massive action to limit emissions || || ||

|-
| rowspan="2"| 2100
| [The middle curve bends a little down after reaching 1.3°C and then continues this path reaching 2°C in 2100. An arrow point from below to it and a label is written below the curve and below 2100 line:] Optimistic scenario|| || ||
|-
| [The last line continues along the path from the last 16 years of the solid line reaching 4.2°C at 2100, almost as far on the other side of 0°C in 150 years as it took 14000 years to move from the other side from the start of the chart. Another arrow point to this from below with a label below the curve and below 2100 line:] Current Path || || ||
|}

===Sources===
The image attributes climate data sources as "Shakun et al. (2012), Marcott et al. (2013), Annan and Hargreaves (2013), HadCRUT4, IPCC":
* Shakun et al. (2012) - [http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html Nature], [http://www.atm.damtp.cam.ac.uk/mcintyre/shakun-co2-temp-lag-nat12.pdf (pdf)]
* Marcott et al. (2013) - [http://science.sciencemag.org/content/339/6124/1198 Science], [http://www.atm.damtp.cam.ac.uk/mcintyre/shakun-co2-temp-lag-nat12.pdf (pdf)]
* Annan and Hargreaves (2013) - [http://www.clim-past.net/9/367/2013/cp-9-367-2013.html Climate of the Past] [http://www.jamstec.go.jp/frsgc/research/d5/jdannan/LGM_temp.pdf (pdf)]
* {{w|HadCRUT#HadCRUT4 wikipedia|HadCRUT4}} - [http://www.metoffice.gov.uk/hadobs/hadcrut4/ Official site]
* {{w|Intergovernmental_Panel_on_Climate_Change|IPCC}} -[http://www.ipcc.ch/ Official site]

==Transcript==
'''Note''' there are several spelling errors in the comic, so please do only correct spelling errors that are not part of the comic! See more in the [[#Trivia|trivia section]].
:[A large heading, followed by a sub-caption. Below that two lines with a statement in between:]
:<big>A timeline of Earth’s average temperature</big>
:since the last ice age glaciation
:When people say “The climate has changed before,” these are the kinds of changes they’re talking about.

:[A very long chart below the headings above is headed with a label for the scale of the X-axis above the chart. Below that a sub-caption. To the left an arrow down to the top of the chart pointing to the dotted curves starting point (at -4.3°C) with a label above the arrow. And arrow pointing left to the left of the center and another pointing right to the right of the center has labels. Below these is the temperature scale of the X-axis, with 9 ticks between the borders each with a label ranging from -4 to +4°C, but with another step in each direction not labeled towards to axis so the chart covers -5 to +5°C.]
:'''Temperature'''
: Compared to the 1961-1990 average
:Start
:Colder
:Warmer
:-4°C -3°C -2°C -1°C 0°C +1°C +2°C +3°C +4°C

:[To the right of the chart is a gray text standing on the side down along the outer boarder of the chart with the sources for the chart:]
: Source: Shakun et. al. (2012) , Marcott et. al. (2013), Annan and Hargreaves (2013) , HadCRUT4, IPCC 

:[The chart is split in 10 columns by the temperature scale and the borders. The two central columns are white, and then from there to the left the background becomes a faded color that changes from light blue to blue at the edge in four steps. Similarly to the right the color changes from light red to red. To the left there is a time scale taking 500 years leaps from 20,000 BCE all the way to year 1, where there are two years, one for BBC and one for CE. The 500 year leaps continue until 1500 CE and from there the steps are down to 100 years until 2100 with also present day 2016 labeled. After 1500 the CE is omitted. The labels stop there, but there is space below covering down to 2200 CE. There is clearly visible division line across the chart on the level of each of the 500 step, and fainter lines for each of the 100 steps all the way even though only the last 5 of these 100 steps are labeled. There is a similar clear line at 2016. Below each step on the Y-axis is noted, and then any text starting before the next step is noted below indented. If there are extra image belonging to text this is indented once more. The graph that the whole chart is about is a dotted line that begins at the “start” point mentioned above at -4.3°C and then begins to go straight down. It will change left and right all the way down. To being with all text and most drawings are to right of the dotted curve. Whenever something is to the left it will be noted. When it says to the left above something, and then nothing over the next, then the next will be to the right. Only at the very bottom are there more entries to the left than right. ]
:20000 BCE
::[An arrow goes from the dotted line to the central line at 0°C. In the middle of the line there is a temperature label:]
::4.3°C
::At the start of our timeline, 22,000 years ago, Earth is 4°C colder than during the late 20th century.
::Boston is buried under almost a mile of ice, and the glaciers reach as far south as New York City.
:::[The Statue of Liberty is shown in front of a glacier front. A very tiny Cueball is on top of the glacier. The drawing is labeled and so is also the glacier.]
:::New York
:::Ice
:::[A guy with a white knit cap is seen walking in a snowy landscape leaving black footprints behind him. He walks through the white central part of the chart.]
:::[The skyline of Boston is shown with two clear buildings among all the other. Above it is a line and in between this area has been filled with thin lines. The drawing is labeled and so is this area. Also the skyline has an arrow pointing at it with a label:]
:::Boston
:::Ice
:::Modern skyline

:19500 BCE
::But the world is about to warm up.
::By this time, humans have already spread across Africa, Eurasia, and Australia.
::They’ve created painting, pottery, rope, and bows and arrows, but haven’t developed writing or farming.

:19000 BCE
::Changes in the Earth’s orbit mean that more sunlight reaches the polar ice…
:::[A line chart with a labeled Y-axis with three labeled ticks. The curve starts up and then goes down five times and up four times ending down. There is one plateau towards the end compared to the rest of the curve where the ups and downs are quite alike.]
:::Summer sun W/m2 at 60°N
:::550
:::500
:::450

:18500 BCE
::[A map of the world. At the top is a light gray area covering North America, Greenland and northern Europe and most of the northern part of Russia. A similar gray area covers Antarctica. There are two labels in the gray area above and one in the gray area below:]
::Ice Ice
::Ice

:18000 BCE
::…And the ice sheets start to melt.

:17500 BCE
::Temperatures have been creeping upward, but around this point, CO2 levels start to climb…

:17000 BCE
::…And then the warming speeds up.

:16500 BCE
::[Cueball is standing with a spear just the right of the graph talking to a rabbit.]
::Cueball: Still pretty cold.

:16000 BCE
::[Megan points to the graph to the right of her and between her and Ponytail standing on the other side. Mean is the first drawing on the left side of the dotted curve, which has hardly moved since the beginning, only to just on the other side of 4°C.]
::[In the right part of the chart is an explanation of the data. Below the first two lines there are four drawings each showing possible temperature swings in reality compared to the smoothed data that represents the dotted curve of the entire chart. The dotted curve is shown in all four drawings and a thin line is shown running along it but with much more fluctuation left and right on the first two, a large spike right on the third and a large bump way right on the fourth. Above these there are two labels. The first labels is inside a bracket that covers the first three, and the last label is for the last drawing. Below is a list of sources.]
::Limits of this data:
::Short warming or cooling spikes might be “smoothed out” by these reconstructions but only if they’re small or brief enough.
:::Possible Unlikely
::Reconstructions are from Shakun (2012) and Marcott (2013), scaled to Annan + Hargreaves (2013) estimate for the last glacial period.

:15500 BCE
::In what is now France, humans paint murals on the walls of the Lascaux caves
::[Hairy paints three animals, two with horns, and two humans, Cueball holding hand with Hairy who has a spear. On the other side of the central line Megan writes three letters, the last of which is reversed.]
:::NIИ

:15000 BCE
::Ice sheets around Alaska shrink, exposing a land bridge between Asia and North America
::[From around the bottom if this section and down to 11500 BCE the dotted curve moved steadily to the right towards warmed temperature peaking close to -1.5°C. Before this the temperature had not moved much away from that at the start.]

:14500 BCE
::[Cueball walks right looking back at the graph behind him. Megan walks in front of him pointing further right.]
::Cueball: Cool.

:14000 BCE
::The edge of the ice withdraws from New York City and retreats North.
::[A large glacier front speaks in a speech bubble with an arrow pointing at it. Behind is there are four peaks in the horizon and in front of it three small melting pools and some rocks on the ground.]
::Glacier: ''That’s it! I’m moving to Canada!''

:13500 BCE
::Humans domesticate dogs
::(Date uncertain, may be much earlier)
::[Megan and Cueball is watching a wolf looking at them.]
::Megan: Okay, you can live in our homes and we’ll feed you, but we’ll still get mad f you poop on the floor.
::Wolf: Deal.
::Cueball: And we get to breed you to be tiny and dress you in little costumes.
::Wolf: …Wait.

:13000 BCE
::[Randall did not use the normal spelling for Woolly Rhino, but this is an accepted alternative spelling:]
::Wooly Rhino goes extinct
::Oregon is scoured by huge floods as glacial dams burst and lakes of meltwater flow to the sea

:12500 BCE
::Ice sheets withdraw from Chicago

:12000 BCE
::Humans settle Abu Hureyra in Syria

:11500 BCE
::[An arrow on the left side of the dotted curve is pointing down along the dotted curve and to the left indicate temperature is declining again, meaning the dotted curve now moves left to colder temperatures. This only continues until 10500 BCE. It is only the second time something is noted on the left side after Megan at 16000 BCE]
::Temperatures start to decline, mainly in the Northern hemisphere
::This may be caused by changes in ocean circulation due to the floods of cold fresh meltwater flowing into the Atlantic as the North American ice sheet melts.
::This cooler period is called the Younger Dryas

:11000 BCE
::[This is the first text to the left of the dotted curve:]
::Humans reach Argentina

:10500 BCE
::[An arrow pointing down along the right side of the dotted curve and to the right indicate temperature is increasing again, meaning the dotted curve now moves right to hotter temperatures. This continues until 8000 BCE where it levels out just above 0°C.]
::Warming resumes
::Human settlements at Jericho

:10000 BCE
::First development of farming

:9500 BCE
::Saber-toothed cat goes extinct
::[To the left:]
::Horses disappear from North America

:9000 BCE
::[To the left, Randall spelled Pokémon wrong:]
:::Last North American Pokemon go extinct
:::[Cueball with a speak and Megan is looking up at this last “fact”.]
:::Megan: That is not a real fact.
::Temperatures reach modern levels
::Rising seas cut off the land bridge between North America and Asia
::Cattle domesticated

:8500 BCE
::Ice sheets retreat across the Canadian border
::Temperatures start to level out slightly above 1961-1990 levels

:8000 BCE
::[The above sentence breaks over the 8000 BCE line. From here a maximum in temperature on the chart is reached at 0.5°C which will not be overtaken until 2000 CE. It stays almost constant here until 5000 BCE where a slight cooling begins.]

:7500 BCE
::[To the left:]
::This warm, stable period is called the Holocene Climate Optimum
::[To the left:]
::Jiahu settled in China

:7000 BCE
::Final collapse of the North American ice sheet leads to rapid 2-4m sea level rise…
::[A small arrow points down and left to the right of the dotted curve. There is a small decrease in temperature but it is very small and would have been missed without the arrow and label.]
::…And a period of cooling in the Northern hemisphere

:6500 BCE
::[To the left:]
::As seas rise to near their modern levels, Britain is cut off from mainland Europe

:6000 BCE
::Humans develop copper metalworking

:5500 BCE
::[To the left:]
::Massive volcanic eruption in Oregon creates crater lake
::Gold metalworking

:5000 BCE
::[To the left:]
::Invention of the wheel
::[To the left. To the right of the dotted curve is an arrow pointing down and slightly left. From here temperature decreases very slowly but steadily from 0.5°C until 1000 BCE where a stable plateau is reached around 0°C.]
::Earth begins to cool slowly mainly due to regular cycles in its orbit

:4500 BCE
::[To the left:]
:: Proto-Indo-European language develops
:::[To the right of the curve Ponytail holds up a hand towards Cueball.]
:::Ponytail: Let’s make out language heavily inflected, so future students have to memorize a zillion verb endings!
:::Cueball: Okay!
::[To the left:]
::Permanent settlements in the fertile crescent

:4000 BCE
::Horses domesticated
::[To the left:]
::Minoan culture arises on Crete

:3500 BCE
::Egyptian mummification
::Rise of the Indus Valley civilization
::[To the left:]
::Invention of writing in Sumer “prehistory” ends, “history” begins
::Earliest human whose name we know
::(Pharaoh Iry-Hor in Egypt)

:3000 BCE
::''Three Sovereigns and five emperors'' period in China
::Gilgamesh
::[To the left:]
::Imhotep
::Mayan culture emerges
::[To the left:]
::Great Pyramid constructed

:2500 BCE
::Corded Ware culture in Europe
::[To the left of the curve two rock musicians with long hair and electrical guitars are standing on either side of a small gate made of three slabs of stone, one on top of the other two standing stones.]
::Stonehenge completed
::Chariots developed

:2000 BCE
::[To the left:]
::Alphabetic writing developed in Egypt
::Last mammoths on a tiny Siberian island go extinct
::[To the left:]
::Minoan eruption

:1500 BCE
::[To the left:]
::Iron smelting
::Olmec civilization develops in Central America
::[A Trojan horse with two Cueball-like guys in front and a third standing on its back. Its back is at three Cueball’s height and its head rises to the level of the Cueball on its back. It stands on a platform with four wheel on the visible side. There is text on the horse]
:::Setting of the ''Iliad'' and the ''Odyssey''
:::Text on horse: Not a trap
::[To the left:]
::Invasion of the Sea peoples*
::* A real thing
::Polynesians explore the Pacific Ocean

:1000 BCE
::[From 1000 BBC to 1000 CE the temperature is stable and very close to 0°C.]
::[To the left:]
::Solomon
::[Randall spelled Iliad wrongly this time:]
::Illiad and Odyssey composed
::[To the left:]
::Rise of Greek city-states
::Neo-Assyrian empire
::[To the left:]
::First Olympics
::Zapotec writing in modern Mexico
::[To the left:]
::Confucius

:500 BCE
::[To the left:]
::The stuff in the 300 (film)|movie ''300'', but regular speed and with more clothing
::Buddha
::Nazca Lines
::[To the left:]
::Alexander the Great
::[To the left:]
::Mayan hieroglyphics
::Ashoka the Great
::[To the left:]
::Paper invented
::[To the left:]
::Asterix
::Teotihuacán metropolis
::[To the left:]
::Julius Caesar

:[At the year 0, there is instead two numbers for each of the two scales before and after Christ:]
:1 BCE
:1 CE
::[To the left:]
::Roman Empire
::Jesus
::[To the left and erupting volcano.]
::Pompeii
::Three Kingdoms period
::[To the left:]
::Gupta empire
::[To the left:]
::Various groups take turns sacking Rome
::[Randall spelled Attila wrong:]
::Atilla the Hun

:500 CE
::Muhammad
::[To the left:]
::Tang Dynasty
::[An arrow to the right of the dotted curve pointing down, takes a swing far out from the curve and then bends back again. The text label next to it breaks into the next 500 period. The dotted curve stays stable at 0°C along this arrow.]
::Medieval warm period in Europe and some northern regions (too regional to affect the global average much)
::[To the left:]
::Leif Eriksson

:1000 CE
::[The dotted curve moves to the left towards lower temperature reaching a minimum around 1650 of about -0.6°C at the Little Ice Age.]
::[To the left a drawing of a compass with needle pointing the black end towards north west. There are labels for the four main directions and a label next to it:]
:::N
:::E W
:::S
:::Magnetic compass navigation
::[To the left:]
::Ghengis Khan
::Zheng He’s fleet explores Asia and Africa
::[To the left:]
::Aztec Alliance
::[To the left:]
::Printing press
::[To the left:]
::Columbus

:1500 CE
::European Renaissance
::[To the left:]
::Shakespeare

:1600
::[To the left:]
::Newton
::[To the right of the dotted curve there is an arrow pointing down that makes a swing in towards the curve and then back out again. At -0.6°C this is the coldest it has been since 9500 BCE. It is labeled:]
::”Little Ice Age”

:1700
::Steam engines
::[To the left:]
::Unites States Independence

:1800
::Industrial Revolution
::[To the left:]
::Telegraphs
::[After this the dotted curve becomes solid.]

:1900
::[To the left, and on the line for 1900:]
::Airplanes
::[To the left:]
::World Wars
::[The solid line takes a step to the right close to 0°C. Over the rest of the 1900s it moves closer to 0°C crossing it before 2000 where it almost reaches the maximum temperature of 0.5 °C from earlier in 8000 BCE.]
::Fossil fuel CO2 emissions start rapidly increasing
::[To the left:]
::Nuclear weapons
::[To the left:]
::Internet

:2000
::Northwest Passage opens
::[From here to present day the solid line increases rapidly and in 2016 present day is almost reaches 1°C, with about 0.8°C.]

:2016
::[To the left on the line for 2016:]
::Present day
::[From here the curve once again becomes dotted as this is the future. After one dot it splits in two and after the first two dots another split between them occurs forming three possible future dotted curves. The first curve bending down before the others, and thus to the right of the other two reaches about 1.2°C and then goes straight down and stops at the 2100 line. An arrow points to it from the left and a label is written patly before and the rest after the 2100 line to the left of the curve:]
::Best-case scenario assuming immediate massive action to limit emissions

:2100
::[The middle curve bends a little down after reaching 1.3°C and then continues this path reaching 2°C in 2100. An arrow point from below to it and a label is written below the curve and below 2100 line:]
::Optimistic scenario
::[The last line continues along the path from the last 16 years of the solid line reaching 4.2°C at 2100, almost as far on the other side of 0°C in 150 years as it took 14000 years to move from the other side from the start of the chart. Another arrow point to this from below with a label below the curve and below 2100 line:]
::Current Path

==Trivia==
*There have been several ''[[:Category:Large drawings|large drawings]]'' in the history of xkcd, and also some that are bigger than this one (for instance [[1110: Click and Drag]]).
**But among those that can be viewed in one go, without downloading a larger file or moving around, this is by far the longest.
**The next longest is probably [[482: Height]].
*The timeline starts at 20,000 BCE (22,000 years ago) and ends at 2100 CE, thus covering 22,100 years.
*There are several spelling mistakes.
**Most obvious is the second time Randall wrote the word "Iliad," because he just spelled it correctly at 1500 BCE and then spelled it ''Illiad'' at 1000 BCE with two "L"s.
**Attila the Hun becomes ''Atilla the Hun'' with ''one'' T and ''two'' L's.
**Pokémon is spelled ''Pokemon'', but then again that is not so strange for Randall (see [[1647: Diacritics]]).
**Note that the fact that Woolly rhinoceros becomes ''Wooly rhino'' with only one l is not a spelling mistake but an alternative spelling of the word.

===Popularity of comic===
*This comic became so popular with a broader audience that Randall decided to push the release of the next comic one day back to Thursday instead of Wednesday.
**He noted this above the comic in the [http://www.explainxkcd.com/wiki/images/6/6d/1732_Earth_Temperature_Timeline_header_text_changed.png header text on xkcd]:
::Note: Since a lot of new people are here looking for this chart today,
::I'll be posting Wednesday's comic on Thursday instead.
*Before that the [http://web.archive.org/web/20160912181546/https://xkcd.com/ normal heading] with the release day of xkcd was shown.
**This was also the [http://web.archive.org/web/20160913231501/http://xkcd.com/ day after] the release.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Large drawings]]
[[Category:Charts]]
[[Category:Timelines]]
[[Category:Line graphs]]
[[Category:Maps]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring real people]] 
[[Category:Multiple Cueballs]]
[[Category:Climate change]]
[[Category:Science]]
[[Category:Animals]]
[[Category:Music]] 
[[Category:Fiction]] 
[[Category:Sport]] 
[[Category:Religion]] 
[[Category:Internet]]
[[Category:Pokémon]]

1731: Wrong

2016-09-10T03:34:50Z

162.158.74.44:

{{comic
| number = 1731
| date = September 9, 2016
| title = Wrong
| image = wrong.png
| titletext = Hang on, I just remembered another thing I'm right about. See...
}}

==Explanation==
{{incomplete|More on White Hat's new theory from the last panel. The abstraction of the particle idea not explained.}}

All objects on Earth are matter, meaning they are made of {{w|Atom|atoms}}, which are specifically '''not''' made up of {{w|antimatter}}. Atoms, while once (when they were named) believed to be the smallest unit of matter, are now known to be made up of {{w|Proton|protons}}, {{w|Neutron|neutrons}} and {{w|Electron|electrons}}. Protons and neutrons are in turn made up of {{w|Quark|quarks}}. Quarks come in six different "{{w|Flavour (particle physics)|flavors}}" (up, down, top, bottom, charm, and strange), with protons and neutrons being made of the first two types. Each quark also has a corresponding {{w|Antiparticle|antiparticle}}, antiquark, which would make up antiprotons and antineutrons.

[[White Hat]] and [[Megan]] appear to be discussing the topics of {{w|Antimatter|antimatter}} and subatomic particles. White Hat makes the assertion that we (referring to people and objects) are made partially of antimatter, because, as he claims, a proton (one of the particles which makes up all matter) is made of two quarks and an antiquark. In fact, protons are made up of two up quarks and a down quark. He is making the simple mistake of mixing up the difference between flavors of quarks with the difference between particles and antiparticles. He continues to elaborate on his idea by mentioning neutrons, which are made of two down quarks and an up quark, but, by his reasoning, they would be made of two antiquarks and and a quark.

When Megan (accurately) doubts this claim, White Hat takes out his smartphone to look it up, in order to show Megan that he is correct. However, upon seeing results (from Wikipedia or another site), he realizes that he was in fact '''wrong''' (hence the title). Not wanting to be incorrect or give up his position in the discussion, he convinces himself that he wasn't actually wrong, (he mentally deletes the realization that he was wrong as shown in the next panel) and instead completely changes the topic (...) to try and re-frame it so he may in some convoluted way not be completely wrong. White Hat may have been incorrectly remembering that, while the valence quarks in a proton are all matter, quantum field theory says that protons also contain an indefinite number of "virtual" anti-quarks, quarks, and gluons. (See this video ''[https://www.youtube.com/watch?v=LraNu_78sCwv What are Quarks?]'' about this). The comic shows him crossing out his thought bubble: this may be analogous to annihilation that occurs when particles meet antiparticles.

It is rather common to not admit fault, the whole topic of this comic, and instead trying to maintain an air on infallibility and intelligence. Some people are just too prideful to admit that they are inherently fallible; White Hat is one of those people, as depicted in several of his earlier appearances. [[Randall]] uses this comic to criticize people who are unable to put aside their ego and re-assess what they know in the face of empirical data; such thinking flies directly against scientific rigor (adding an extra layer of irony to the situation, since White Hat and Megan are discussing a ''scientific'' topic).

White Hat's new topic, where he can be right, includes the {{w|Quantum field theory}}, a very complicated field, which it is likely that Megan do not know so much about (inferred by the fact that she was not quite sure about the anti-quarks). So he could maybe tell her something she could not refute, and then claim to be right. Megan, however, recognizes exactly what he is trying to do, and can only sigh in response to his failed efforts.

In the title text, White Hat just remembers another thing he's right about. This shows that he is not interested in a discussion but only in being right, and he proceeds to prove his point by explaining this other topic (hinted to at the end of the title text). He most likely will simply be wrong again, as per the title of this comic. This bears some similarity to [[386: Duty Calls]], in which [[Cueball]] stays up late correcting someone on the Internet.

This comic could be seen as a follow up to [[1605: DNA]]. Going back through the last White Hat appearances it turns out that DNA, 13 comics back, is actually the last where White Hat has been the fall guy. For instance he has the opposite role in [[1640: Super Bowl Context]], and he is not "the stupid guy" in the 9 comics between that and this one, but often just another guy than Cueball. Back in [[1255: Columbus]] he again was the fall guy, and again it reminds a bit about this comic, actually Megan even begins with a sigh like she finished this one.

Quarks are also referenced in [[1418: Horse]], [[1621: Fixion]] and the first time they were mentioned, in [[474: Turn-On]], the up and down flavor was also mentioned. Antimatter is also referenced in [[683: Science Montage]], [[826: Guest Week: Zach Weiner (SMBC)]] and [[1621: Fixion]] as well as being the subject of the [[what if?]] ''{{what if|114|Antimatter}}''. It was also mentioned in another ''what if?'': ''{{what if|79|Lake Tea}}''.

A similar thought process where earlier thoughts are scribbled out was used by Cueball in [[1650: Baby]], but for different reasons.

==Transcript==
:[White Hat is walking beside Megan, index finger extended]
:White Hat: Really, we're all made of antimatter. A proton consists of two quarks and an antiquark.
:Megan: ...I don't think that's right.

:[White Hat stops to take out his smartphone tapping on it. Megan stops and turns towards him.]
:White Hat: Sure it is. Neutrons are, too.
:Megan: Do you mean "up" and "down" quarks? I think antiquarks are a different thing.
:White Hat: No, let me show you...
:Tap
:Tap

:[Zooming in on White Hat's head, while he is holding his phone up looking at it. He is thinking as shown with a bubbly thought bubble.]
:White Hat (thinking): I'm...wrong?

:[White Hat has lowered the phone. He is still thinking the same but the text has been scribbled out.]
:White Hat (thinking): I'm...wrong?

:[White Hat purges the thought from his mind]
:White Hat (thinking): ...

:[Similar setting as in the first panel, but in a full row wide panel, and White Hat is still holding his smartphone]
:White Hat: Really, the whole idea of "particles" is inaccurate. These are abstractions arising quantum field theory, but what most people don't realize is...
:Megan: *Sigh*

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Megan]]
[[Category:Physics]]
[[Category:Smartphones]]

1731: Wrong

2016-09-09T17:56:28Z

162.158.74.44: /* Transcript */

{{comic
| number = 1731
| date = September 9, 2016
| title = Wrong
| image = wrong.png
| titletext = Hang on, I just remembered another thing I'm right about. See...
}}

==Explanation==
{{incomplete|The new theory White Hat mentions in last panel not explained. Examples of comics similar white hat behavior. And of anitmater what if articles}}

All objects on Earth are matter, meaning they are made of {{w|Atom|atoms}}, which are specifically '''not''' made up of {{w|antimatter}}. Atoms, while once (when they were named) believed to be the smallest unit of matter, are now known to be made up of {{w|Proton|protons}}, {{w|Neutron|neutrons}} and {{w|Electron|electrons}}. Protons and neutrons are in turn made up of {{w|Quark|quarks}}. Quarks come in six different "{{w|Flavour (particle physics)|flavors}}" (up, down, top, bottom, charm, and strange), with protons and neutrons being made of the first two types. Each quark also has a corresponding {{w|Antiparticle|antiparticle}}, antiquark, which would make up antiprotons and antineutrons.

[[White Hat]] and [[Megan]] appear to be discussing the topics of {{w|Antimatter|antimatter}} and subatomic particles. White Hat makes the assertion that we (referring to people and objects) are made partially of antimatter, because, as he claims, a proton (one of the particles which makes up all matter) is made of two quarks and an antiquark. In fact, protons are made up of two up quarks and a down quark. He is making the simple mistake of mixing up the difference between flavors of quarks with the difference between particles and antiparticles. He continues to elaborate on his idea by mentioning neutrons, which are made of two down quarks and an up quark, but, by his reasoning, they would be made of two antiquarks and and a quark.

When Megan (accurately) doubts this claim, White Hat takes out his smartphone to look it up, in order to show Megan that he is correct. However, upon seeing results (from Wikipedia or another site), he realizes that he was in fact '''wrong''' (hence the title). Not wanting to be incorrect or give up his position in the discussion, he convinces himself that he wasn't actually wrong, (he mentally deletes the realization that he was wrong as shown in the next panel) and instead completely changes the topic (...) to try and re-frame it so he may in some convoluted way not be completely wrong.

It is rather common to not admit fault, the whole topic of this comic, and instead trying to maintain an air on infallibility and intelligence. Some people are just too prideful to admit that they are inherently fallible; White Hat is one of those people, as depicted in several of his earlier appearances.

Megan, however, recognizes exactly what he is trying to do, and can only sigh in response to his failed efforts.

In the title text, White Hat just remembers another thing he's right about. This shows that he is not interested in a discussion but only in being right! The title begins with White Hat starting to explain this other thing he is right about. He most likely will simply be wrong again, as per the title of this comic.

This comic could be seen as a follow up to [[1605: DNA]]. Going back through the last White Hat appearances it turns out that DNA, 13 comics back, is actually the last where White Hat has been the fall guy. For instance he has the opposite role in [[1640: Super Bowl Context]], and he is not "the stupid guy" in the 9 comics between that and this one, but often just another guy than [[Cueball]].

Quarks are also mentioned in [[474: Turn-On]] and antimatter is mentioned in various ''[[what if?]]'' articles.

==Transcript==
:[White Hat is walking beside Megan, index finger extended]
:White Hat: Really, we're all made of antimatter. A proton consists of two quarks and an antiquark.
:Megan: ...I don't think that's right.

:[White Hat stops to take out his smartphone tapping on it. Megan stops and turns towards him.]
:White Hat: Sure it is. Neutrons are, too.
:Megan: Do you mean "up" and "down" quarks? I think antiquarks are a different thing.
:White Hat: No, let me show you...
:Tap
:Tap

:[Zooming in on White Hat's head, while he is holding his phone up looking at it. He is thinking as shown with a bubbly thought bubble.]
:White Hat (thinking): I'm...wrong?

:[White Hat has lowered the phone. He is still thinking the same but the text has been scribbled out.]
:White Hat (thinking): I'm...wrong?

:[White Hat purges the thought from his mind]
:White Hat (thinking): ...

:[Similar setting as in the first panel, but in a full row wide panel, and White Hat is still holding his smartphone]
:White Hat: Really, the whole idea of "particles" is inaccurate. These are abstractions arising quantum field theory, but what most people don't realize is...
:Megan: *Sigh*

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Megan]]
[[Category:Physics]]
[[Category:Smartphones]]

1731: Wrong

2016-09-09T17:51:39Z

162.158.74.44:

{{comic
| number = 1731
| date = September 9, 2016
| title = Wrong
| image = wrong.png
| titletext = Hang on, I just remembered another thing I'm right about. See...
}}

==Explanation==
{{incomplete|The new theory White Hat mentions in last panel not explained. Examples of comics similar white hat behavior. And of anitmater what if articles}}

All objects on Earth are matter, meaning they are made of {{w|Atom|atoms}}, which are specifically '''not''' made up of {{w|antimatter}}. Atoms, while once (when they were named) believed to be the smallest unit of matter, are now known to be made up of {{w|Proton|protons}}, {{w|Neutron|neutrons}} and {{w|Electron|electrons}}. Protons and neutrons are in turn made up of {{w|Quark|quarks}}. Quarks come in six different "{{w|Flavour (particle physics)|flavors}}" (up, down, top, bottom, charm, and strange), with protons and neutrons being made of the first two types. Each quark also has a corresponding {{w|Antiparticle|antiparticle}}, antiquark, which would make up antiprotons and antineutrons.

[[White Hat]] and [[Megan]] appear to be discussing the topics of {{w|Antimatter|antimatter}} and subatomic particles. White Hat makes the assertion that we (referring to people and objects) are made partially of antimatter, because, as he claims, a proton (one of the particles which makes up all matter) is made of two quarks and an antiquark. In fact, protons are made up of two up quarks and a down quark. He is making the simple mistake of mixing up the difference between flavors of quarks with the difference between particles and antiparticles. He continues to elaborate on his idea by mentioning neutrons, which are made of two down quarks and an up quark, but, by his reasoning, they would be made of two antiquarks and and a quark.

When Megan (accurately) doubts this claim, White Hat takes out his smartphone to look it up, in order to show Megan that he is correct. However, upon seeing results (from Wikipedia or another site), he realizes that he was in fact '''wrong''' (hence the title). Not wanting to be incorrect or give up his position in the discussion, he convinces himself that he wasn't actually wrong, (he mentally deletes the realization that he was wrong as shown in the next panel) and instead completely changes the topic (...) to try and re-frame it so he may in some convoluted way not be completely wrong.

It is rather common to not admit fault, the whole topic of this comic, and instead trying to maintain an air on infallibility and intelligence. Some people are just too prideful to admit that they are inherently fallible; White Hat is one of those people, as depicted in several of his earlier appearances.

Megan, however, recognizes exactly what he is trying to do, and can only sigh in response to his failed efforts.

In the title text, White Hat just remembers another thing he's right about. This shows that he is not interested in a discussion but only in being right! The title begins with White Hat starting to explain this other thing he is right about. He most likely will simply be wrong again, as per the title of this comic.

This comic could be seen as a follow up to [[1605: DNA]]. Going back through the last White Hat appearances it turns out that DNA, 13 comics back, is actually the last where White Hat has been the fall guy. For instance he has the opposite role in [[1640: Super Bowl Context]], and he is not "the stupid guy" in the 9 comics between that and this one, but often just another guy than [[Cueball]].

Quarks are also mentioned in [[474: Turn-On]] and antimatter is mentioned in various ''[[what if?]]'' articles.

==Transcript==
:[White Hat holding a finger up is walking behind Megan.]
:White Hat: Really, we're all made of antimatter. A proton consists of two quarks and an antiquark.
:Megan: ...I don't think that's right.

:[White Hat stops to take out his smartphone tapping on it. Megan stops and turns towards him.]
:White Hat: Sure it is. Neutrons are, too.
:Megan: Do you mean "up" and "down" quarks? I think antiquarks are a different thing.
:White Hat: No, let me show you...
:Tap
:Tap

:[Zooming in on White Hat's head, while he is holding his phone up looking at it. He is thinking as shown with a bubbly thought bubble.]
:White Hat (thinking): I'm...wrong?

:[White Hat has lowered the phone. He is still thinking the same but the text has been scribbled out.]
:White Hat (thinking): I'm...wrong?

:[White Hat continues to think of something else]
:White Hat (thinking): ...

:[Exactly same setting as in the first panel, but in full row wide panel, but White Hat still has his smartphone in his hand while walking with his other hand holding up a finger.]
:White Hat: Really, the whole idea of "particles" is inaccurate. These are abstractions arising quantum field theory, but what most people don't realize is...
:Megan: *Sigh*

{{comic discussion}}

[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Megan]]
[[Category:Physics]]
[[Category:Smartphones]]

1731: Wrong

2016-09-09T04:30:26Z

162.158.74.44: /* Explanation */

{{comic
| number = 1731
| date = September 9, 2016
| title = Wrong
| image = wrong.png
| titletext = Hang on, I just remembered another thing I'm right about. See...
}}

==Explanation==
{{incomplete|Just a couple sentences to kick things off.}}

Some people are just too prideful to admit that they are inherently fallible. White Hat is one of those people.

==Transcript==
{{incomplete transcript}}

:[White Hat and Megan are walking.]

:White Hat: Really, we're all made of antimatter. A proton consists of two quarks and an antiquark.

:Megan: ...I don't think that's right.

:White Hat: Sure it is. Neutrons are, too.

:Megan: Do you mean "up" and "down" quarks? I think antiquarks are a different thing.

:White Hat: No, let me show you...

:[White Hat takes out a cell phone.]

:Cell Phone: tap tap

:White Hat [thinking]: I'm...wrong?

:["I'm...wrong?" is scribbled out]

:White Hat [thinking]: ...

:White Hat: Really, the whole idea of "particles" is inaccurate. These are abstractions arising quantum field theory, but what most people don't realize is...

:Megan: *sigh*

{{comic discussion}}

1022: So It Has Come To This

2016-09-03T05:53:06Z

162.158.74.44: /* Explanation */

{{comic
| number = 1022
| date = February 27, 2012
| title = So It Has Come To This
| image = so_it_has_come_to_this.png
| titletext = 'Come to what?' 'You. Me. This moment.'
}}

==Explanation==
The line "it has come to this" is usually seen on the verge of the climactic confrontation between the villain and his arch rival, or when one character has to unleash their utmost ability etc. Despite its dramatic tone, however, the statement is a content-free tautology, true in all possible scenarios in which time progresses in a forward direction. Accordingly, [[Cueball]] is saying it when [[Megan]] tells him that they have run out of cat food, a relatively trivial problem, that could be solved with a quick trip to the grocery store.

The title text is a follow-up on the comic dialogue. When Megan replies in confusion, "Come to what?" Cueball then uses another instantly-dramatic phrase that keeps his words ambiguous, only leaving her in the dark. The phrase, "You. Me. This moment." is used when brevity is key, and no information should be leaked to anybody listening. Those conversing then continue the important discussion elsewhere, allowing them to speak more openly.

The phrase "So it has come to this" is also said in: [[225: Open Source]].

==Transcript==
:[Megan holds up an open and empty back with the white silhouette of a cats face on it. Cueball looks down at the bag.]
:Megan: We ran out of cat food.
:Cueball: ''So''
:Cueball: ''It has come to this.''

:[Caption below the panel:]
:Protip: If you're not sure what to say, try "So it has come to this"-it creates instant dramatic tension and is a valid observation in literally any situation.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Protip]]
[[Category:Animals]]

868: Nolan Chart

2016-08-24T04:36:53Z

162.158.74.44:

{{comic
| number = 868
| date = March 4, 2011
| title = Nolan Chart
| image = nolan chart.png
| titletext = Also in the right quadrant are NFPA-compliant chemical manufacturers and Sir Charles Wheatstone. Sharing the top with the internet libertarians are Nate Silver and several politically-active kite designers.
}}

==Explanation==
The [http://www.nolanchart.com Nolan Chart] is a visual representation of the political spectrum that measures not only liberal vs conservative tendencies but also libertarian and statist tendencies. In this comic, it is taken to a different end. One one side are both Democrats and Republicans and on the other side are baseball fans. In the typical Nolan Chart, Libertarians are in the top quadrant, but in this one "Internet Libertarians" take the spot because they love the Nolan Charts (which are found online) and have a lot of political opinions.

Nolan may also refer to baseball hall of famer [http://baseballhall.org/hof/ryan-nolan Nolan Ryan].

In the title text, the NFPA-compliant chemical manufacturers are mentioned because of [http://ehs.okstate.edu/modules/hazcom/nfpadia2.gif this diagram]. Sir Charles Wheatstone was the inventor of the Wheatstone bridge, which is also {{w|File:Wheatstonebridge.svg|diamond-shaped}}. The image text makes reference to Nate Silver, who previously worked for Baseball Prospectus and now writes a data-driven political and sports blog called Five Thirty Eight for ESPN. He is both a lover of diamond-shaped diagrams and has political opinions. Politically-active kite designers both would have strong political opinions (it comes with the territory of being politically active) and would love diamond-shaped diagrams, presumably because they would be interested in blueprints of kites.

==Transcript==
:[Diamond-shaped four-panel diagram.]
:[Top panel labeled "internet libertarians".]
:[Left panel labeled "Democrats, Republicans".]
:[Bottom panel labeled "other".]
:[Right panel labeled "baseball fans".]
:[Axis increasing in the upper-left direction labeled "political opinions".]
:[Axis increasing in the upper-right direction labeled "love of diamond-shaped diagrams".]

{{comic discussion}}
[[Category:Charts]]
[[Category:Comics featuring Nate Silver]]
[[Category:Politics]]
[[Category:Baseball]]
[[Category:Internet]]

704: Principle of Explosion

2016-08-17T14:51:45Z

162.158.74.44: /* Explanation */

{{comic
| number = 704
| date = February 19, 2010
| title = Principle of Explosion
| image = principle_of_explosion.png
| titletext = You want me to pick up waffle cones? Oh, right, for the wine. One sec, let me just derive your son's credit card number and I'll be on my way.
}}

==Explanation==
[[Cueball|Cueball's]] friend (who also looks like Cueball) explains the {{w|principle of explosion}}, a classical law of logic, that says that if you start out with propositions ({{w|axiom}}s) that contradict each other, it is possible to derive (prove) any statement you want in the language you are working in, true or false.

Cueball then proceeds to misinterpret (perhaps intentionally) that you can derive any ''fact'' about the physical world. His formula of {{w|propositional logic}} in the third panel reads "'''P''' and not '''P'''", where '''∧''' is the formal logic symbol for "and" and '''¬''' is the symbol for "not". '''P''' stands for a proposition. As "'''P''' and not '''P'''" is shorthand for "'''P''' is both true and false", this forms a contradiction from which the principle of explosion can begin. Humorously and to his friend's bewilderment he then successfully manages to 'derive' the phone number for his friend's mom.

:'''An example from math''': If you assume that √2 is a rational number, you can 'prove' things that are obviously false, such as the fact that some numbers must be both even and odd. Consequently, you can draw the conclusion that √2 must be an irrational number (provided such a thing exists at all! - luckily, it does and obeys the same calculation rules as for rational numbers; this is how {{w|proof by contradiction}} works.)

:This can be seen in a {{w|Truth Table}}:
:{| class="wikitable"
|-
! P
! ¬P
! P ∧ ¬P
! P ∧ ¬P ⇒ Q
|-
| T
| F
| F
| T
|-
| F
| T
| F
| T
|}

:The formula P ∧ ¬P ⇒ Q is true in every possible interpretation. No matter what propositions are substituted for P and Q the implication is true. So if a single example of a contradiction were found, then every proposition would be true, (and simultaneously false).

After deriving the phone number Cueball instantly calls his friends mom, who turns out to be Mrs. Lenhart. She asks Cueball out, without any preamble, to his friend's vexation. It does not get better when it is obvious that she wishes to drink "cheap" {{w|boxed wine}} with him, and Cueball is free tonight! There is definitely a hint of {{w|Mrs. Robinson}} over Mrs. Lenhart here.

Maybe it is [[Miss Lenhart]] who has married, or she is the mother of both Miss Lenhart and Cueball's friend? She could, in fact, be Cueball's school teacher. He obviously knew her name and is ready to go to her place in an instant.

In the title text we hear more of Cueball's (one-sided) conversation with Mrs. Lenhart. She asks him to pick up waffle cones, a variety of {{w|ice cream cone}}. And when he sounds bewildered by this she explains that it is for drinking the wine. This is probably not a very good idea, since waffles are typically not water proof and would also dissolve into the wine. But it could also be considered kinky; something Mrs. Lenhart's son would not like to hear about. The rest of the title text is just more of the main comic's derivation joke, since Cueball will use a second to derive her son's credit card number, so he can buy the cones at his expense.

Of course we have no proof that he is actually speaking to Mrs. Lenhart. It could just be a prank he is pulling on his annoying mathematically interested friend. All he needed was to have looked her phone number up in advance.

==Transcript==
:[Cueball's Cueball-like friend is talking to him.]
:Friend: If you assume contradictory axioms, you can derive anything. It's called the principle of explosion.
:Cueball: ''Anything?'' Lemme try.

:[Cueball is writing on a piece of paper on a desk.]

:[Cueball is holding up a piece of paper to his friend, while holding a phone.]
:Cueball: Hey, you're right! I started with '''P∧¬P''' and derived your mom's phone number!
:Friend: That's not how that works.

:[The friend is looking at the piece of paper, while Cueball is talking to someone on a phone. The desk from before can be seen to the right.]
:Cueball: Mrs. Lenhart?
:Friend: Wait, this ''is'' her number! How—
:Cueball: Hi, I'm a friend of— Why, yes, I ''am'' free tonight!
:Friend: ''Mom!''
:Cueball: No, box wine sounds lovely!

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Miss Lenhart]]
[[Category:Multiple Cueballs]]
[[Category:Math]]
[[Category:Logic]]

1720: Horses

2016-08-16T16:27:31Z

162.158.74.44:

{{comic
| number = 1720
| date = August 15, 2016
| title = Horses
| image = horses.png
| titletext = This car has 240% of a horse's decision-making ability and produces only 30% as much poop.
}}

==Explanation==
{{incomplete|Is White Hat clearly either a sales man or just owner of a nice new car? Randall's transcript doesn't specify, so discuss in the comments.}}
[https://techcrunch.com/2016/08/10/are-consumers-automakers-and-insurers-really-ready-for-self-driving-cars/ The programming] of {{w|self-driving cars}} has been in the news lately, as engineers and philosophers debate what rules the cars should follow in dangerous situations (for instance, what to do when forced to choose between hitting a pedestrian or swerving into oncoming traffic). [[Randall]], in the form of [[Ponytail]], suggests one approach for solving this problem: to think of the car as behaving like a horse, using its own intelligence and ignoring dangerous commands in the interests of self-preservation.

The comic begins with Ponytail claiming that in the old days, riding a horse or driving a horse drawn vehicle while drunk was less dangerous than {{w|drunk driving}} today. Given the higher speed and the denser traffic today this might seem plausible. On the other hand, modern cars have seat belts, airbags, and other features designed to save lives when crashes do occur; horses and horse-drawn vehicles lacked these safety features. But if you do fall asleep the horse will not suddenly walk into another oncoming horse, and may actually just stop walking while you sleep.

Ponytail expands the argument by stating the horse itself will be acting in the interest of its own self-preservation. She finally states that in a comparison of the ability of self-driving cars, we should forget humans, and instead it should be the ability of horses that should be the benchmark that the self-driving cars should be judged against.

This segues into a scene with [[White Hat]], bragging to Cueball and Megan about the features of a car (either to sell the car or simply boast; it's unclear whether White Hat is acting as a salesman) by comparing the features to those of horses. Car engines are traditionally measured in {{w|horsepower}}, which (roughly) compares the power output of the engine to that of a horse. White Hat goes a step further, claiming he can measure the car's onboard computer's driving abilities in the equivalent number of "horses", comparing the car's ability to mitigate for a drunk driver and/or avoid obstacles to that of a horse. (White Hat has been [http://www.explainxkcd.com/wiki/images/9/9f/lorenz_-_sale_2.png depicted as a salesman] before in [[1350: Lorenz]] and similarly earlier in [[260: The Glass Necklace]]).

The title text features more comparisons of the car to horses. Apparently the car has 240% of a horse's decision-making ability while producing only 30% as much poop. So even with 3.5 horse-intelligence it may only have 2.4 times the decision-making ability (assuming it's the same car). A cars "poop" would be its exhaust, which is usually not found on the road in the form of solid waste but could still nonetheless be measured, as it contains mass. While no source is stated for the 30% ratio, the point that cars are less polluting than horses is surprisingly valid when regarding waste left in the street. Before the invention of the automobile, city streets were commonly filled with horse manure. Of course the amount of pollution created by the cars of the worlds makes them much more toxic both for humans breathing the exhaust fumes and on the larger scale with the climate. (Then again, if there where a horse for each horsepower in all the cars, then that would also be a problem with the release of methane gas etc.)

Note that riding a horse while drunk is in fact still dangerous and illegal in many places (for example, {{w|Licensing Act 1872|the UK and Ireland}}). A badly-driven horse can throw off its owner, trample passersby, fall on bad surfaces, and destroy any wagon or carriage it's pulling. A self-driving car should be able to understand road rules, which a horse will not - which is presumably why the cars in the comic and the title text are both specified as being more intelligent than a horse.

In [[887: Future Timeline]] dogs driving cars are mentioned. Self-driving cars is a [[:Category:Self-driving cars|recurring topic]] on xkcd. In [[1461: Payloads]] spacecraft mass is measured in horses.

==Transcript==
:[Ponytail walks right with Cueball.]
:Ponytail: Drunk driving was less of a problem before cars. If you got on your horse drunk and fell asleep, it could just walk home.

:[Zoom in on Ponytail's torso; she holds up a palm to proffer an idea.]
:Ponytail: And if you tried to ride into a tree, the horse could be like "No."
:Ponytail: Forget human drivers – ''that's'' the benchmark we should be judging self-driving cars against.

:[The front end of a car, with the bottom of the windshield and the right side mirror just inside the panel is parked before White Hat. He is holding his hand, palm up, out to the left towards the car as he brags about it to Megan and Cueball standing in front of him admiring the car. At the top left of the panel a small frame with a caption is placed over the panels frame:]
:Soon:
:White Hat: This baby has 200 horses under the hood and 3.5 in the computer.
:Megan and Cueball: Ooooh!

{{comic discussion}}

[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Megan]]
[[Category:Animals]]
[[Category:Self-driving cars]]

1719: Superzoom

2016-08-15T04:29:52Z

162.158.74.44:

{{comic
| number = 1719
| date = August 12, 2016
| title = Superzoom
| image = superzoom.png
| titletext = *click* Let him know he's got a stain on his shirt, though.
}}

==Explanation==

This comic is inspired by the [[https://www.youtube.com/watch?v=RTJIU0lHhto moon-zoom youtube video]] that made its rounds on the internet in the same week the comic was released. The camera used in the video is a Nikon p900 with a zoom of x83/x166 equivalent to 2000mm. The video demonstrates the camera's ability to capture detailed photographs of the moon's surface.

In this comic, [[Cueball]] is showing off his new {{w|superzoom}} camera to [[White Hat]]. These are cameras with large zoom lenses, often up to 25× or higher magnification. He is very excited and starts by exclaiming how they can take detailed photos of the craters on the {{w|Moon}}, and (on better models) relatively large photos of {{w|Jupiter}} even with a resolution so individual clouds can be seen. (See examples of zoom on these objects [https://www.youtube.com/watch?v=CwLbj0fBvXk here] and [https://www.youtube.com/watch?v=de2LjQ5F3HE here] without cloud resolution though, but with Jupiter's {{w|Galilean moons|four large moons}} and {{w|Saturn|Saturn's}} {{w|Rings of Saturn|rings}}.)

He then spots a bird (which is just a speck in the sky) and uses the superzoom for {{w|birdwatching}}, which is a popular use for these cameras. He can see that it's a {{w|Peregrine falcon}} and that it has been {{w|Bird ringing|banded}} (ringed) and he can even read the number on the band. He then spots an airplane and having taken a picture of it, he can tell that it is a {{w|Boeing 787 Dreamliner|787 Dreamliner}} from {{w|Japan Airlines}}, and he can even make out the registration number. [https://www.youtube.com/watch?v=p-0X3xJf-kg All this is possible], with a {{w|Nikon Coolpix P900}}, which may not be much larger than the one Cueball stands with here, with an extremely long lens. Although it still seem unlikely he would be able to make out the number on the birds band...

Note that before each comment he has taken a picture, presumably zooming further in after each photo of each new object, zooming out again before beginning with the next object.

Finally, White Hat exclaims that he is sold and states that he also want a superzoom camera like Cueball's. Cueball then points the camera down the street takes a picture and tells White Hat that the shop on ''Union Road'' has these camera in stock, indicating that he can see this inside the store (or in their window). He then takes another image and is able to make out not only the worker Kevin inside, he also recognizes him and (as mentioned in the title text after taking yet a further zoomed in picure) notice a stain on Kevin's shirt. He seems to like Kevin and asks White Hat to tell Kevin about the stain when he goes there to buy a superzoom camera.

Even with the ability of these cameras, it would be difficult for Cueball to be able to make out a specific worker inside the store, but if he is standing near a window it is not impossible, and if he has a stain on his shirt, it is in the same league as spotting a band on a bird in the air. Of course he has to be in a spot where he can see straight to the front of the shop.

The last panel and title text is also a remark on how such cameras can be used to spy on people for quite a far distance, which has often been (mis)used by {{w|Paparazzi|paparazzi photographers}} taking pictures of famous people (often while almost naked or in [https://www.youtube.com/watch?v=tANeyKZLF9s bikini] or other bathing clothes). Now everyman gets this disconcerting possibility to spy on their neighbors and others for just a few hundred dollars.

There are lenses that can do what Cueball describes about Jupiter's clouds in the comic (e.g., the [https://www.youtube.com/watch?v=IRq18WpQZC0 Canon 5200mm]), but so far not such a small consumer camera as shown in the illustration.

A couple of other factors that many people may not realize until after they've bought a consumer-level superzoom camera is that a) taking a hand-held picture at maximum zoom is typically rather blurry because the lens is magnifying all vibration and it's impossible to hold the camera steady enough (so a Camera Tripod would be needed), and b) that the lens' aperture at maximum zoom is typically much smaller than at normal focal lengths, with the result that the shutter time must be several times longer to get proper exposure, compounding the vibration / blurry problem. Modern superzoom cameras do have "image stabilization", which can mitigate blurriness due to vibration, but extreme telephoto photography is still more challenging than implied in the comic.

Also having zoomed so much it is very hard to actually locate a moving plane or bird in the sky while looking at the image shown on the camera. And as shown in the comic the lens is zoomed very much in. Of course this could be done by Cueball after having found the flying object with much less zoom. But still if he loses sight of the bird while fully zoomed in it will be almost impossible to find it again without zooming back out.

White Hat and Cueball has discussed photography before in [[1314: Photos]].

==Transcript==
:[White Hat and Cueball are walking right. Cueball is looking down at a camera with a long lens he is holding in both hands.]
:Cueball: I love these superzoom cameras. For a few hundred dollars you can take pictures of Moon craters and Jupiter's clouds.

:[They stop, White Hat looks up in the air while Cueball does the same but through the camera he is holding up to his eye while taking pictures. The camera lens is further zoomed out and is clicking.]
:Cueball: And birds! See that speck up there?
:<nowiki>*Click*</nowiki>
:Cueball: Peregrine falcon!
:<nowiki>*Click*</nowiki>
:Cueball: It's banded, too. Want the number?

:[White Hat looks even further up as Cueball turns left and point the even further zoomed camera almost straight up while taking photos.]
:Cueball: And see that plane?
:<nowiki>*Click*</nowiki>
:Cueball: 787 Dreamliner
:<nowiki>*Click*</nowiki>
:Cueball: Japan Airlines.
:<nowiki>*Click*</nowiki>
:Cueball: Registration is—

:[White Hat looks back down on Cueball who has turned to the right holding the fully out-zoomed camera level to the right along the ground.]
:White Hat: OK, I'm sold—I want one.
:<nowiki>*Click*</nowiki>
:Cueball: They're in stock at the place on Union Road.
:<nowiki>*Click*</nowiki>
:Cueball: Hey, Kevin's working today! He's great.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Animals]]