explain xkcd - User contributions [en]

2381: The True Name of the Bear

2020-11-09T01:43:55Z

108.162.219.168: /* Explanation */

{{comic
| number = 2381
| date = November 4, 2020
| title = The True Name of the Bear
| image = the_true_name_of_the_bear.png
| titletext = Thank you to Gretchen McCulloch for fielding this question, and sorry that as a result the world's foremost internet linguist has been devoured by the brown one. She will be missed.
}}

==Explanation==
{{incomplete|Created by THE BEAR WHO MUST NOT BE NAMED. There are some more mainstream hypotheses in the linked material that could be included. Sir, madam, or variation thereupon under the username Gbisaga, your linguistic speculations are honestly interesting. However, they’re original research. Please find a citation. Another Reader says: Now, I thought the point here was to explain the comic, not be encyclopedic, no? Randall discusses a lot of obscurely known things that don't have good citations available (mostly regarding STEM culture). Not true for etymology I suppose. Do NOT delete this tag too soon.}}

The Canadian Internet linguist {{w|Gretchen McCulloch}} [https://twitter.com/gretchenamcc/status/1113195661275611137 tweeted] about [https://www.charlierussellbears.com/LinguisticArchaeology.html the theory] that the word for bear became taboo in some branches of Indoeuropean languages - notably the Germanic one - and it was replaced by euphemisms. In the Germanic branch, the euphemism may have been like "the brown one" and words for bear derive from words for "brown".

The Indoeuropean root for bear is *rkto-, which has been inferred from languages that use words derived from it. In the comic, Gretchen McCulloch applies {{w|Sound change|sound shifting}} laws to it to guess how it would have evolved into English, but pronouncing it seems to actually summon a bear, showing that abandoning that word was a fairly wise move for the Germanic language family. Interestingly enough, the hypothesized word “arth” is the same as the Welsh and Cornish for the word “bear.” Welsh belongs to the Celtic language family, which is one of the Indoeuropean branches that still uses a word derived from *rkto-, as the Italic (Romance), Greek and Indoarian (Sanscrit) branches do, while Germanic, Slavic and Baltic branches abandoned it for different euphemisms.

Depending on how one takes the concept of "saying a true name", there may be a consistency problem with the comic, adding to the absurdity of the situation depicted. If saying the "true" name (or any name derived from that name) summons the bear, how is it that the Welsh and most Romance language speakers (e.g. Italians saying Orso, Spaniards saying Oso, etc) get away without being constantly mauled? One explanation might be if the bears only respond to certain languages, but that seems unlikely unless the words mutated specifically into some special sound bears responded to, since the languages that the bears would be prompted by would have developed thousands of years apart in time. An arcane form of {{w|geofencing}}, and/or a {{w|geas}} firmly tied to some prior mystically-established meta-contextualising, might limit such otherworldly 'magic' and explain why more mundane science and logic is usually unworried by these kinds of phenomena being inadvertently triggered.{{Citation needed}}

A view on speaking of bears that is much more likely, is that the cultures were such that when other human beings heard the clear word for bear, they would behave in ways that people did not desire. For example, maybe when someone had a good harvest bears would have a tendency to come into town to investigate or raid their food store. After some time, people might have developed a tendency to discuss bears and lock up their food store after a good harvest, and so if people overheard discussion of bears from their neighbors, they might have all locked down their food stores, and the bears could have learned to key in on the behavior of everyone locking their food stores to actually come into the city and raid them more in response.{{Citation needed}} There are a lot of rational reasons{{Citation needed}} that avoiding speaking of bears to keep them away could have been a real thing that actually worked.

Another possibility is that the "true name" of a bear is actually in a language the bear understands: possibly involving smells, body language, territorial or ecological interspecies behavior, and would actually reliably summon a bear because the person using it knew exactly what they were doing. Hunter-gatherers and very experienced trackers are known to interact with wildlife in such ways.{{Citation needed}} 

Use of true names appears to be [[1013: Wake Up Sheeple|highly effective in the xkcd universe, rather like a fairy tale]], and it is also {{tvtropes|IKnowYourTrueName|a common trope}} elsewhere. Some say a true name contains clear meaning of who someone or something really is. In a competitive culture like ours, this could give others power over you, "profiling" you to be able to predict you and what you do.

Internet Linguist Gretchen McCulloch (or her ghost) certainly found it effective, but https://twitter.com/GretchenAMcC/status/1324044826145378304 may reflect her extreme susceptibility to internet leakage.

== Trivia ==

The last comic strip that ended with the words "Oh no" was [[2314: Carcinization]], which also featured an unfortunate occurrence involving an animal as its punchline when Cueball spontaneously transformed into a crab.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[Megan walks in front the left, looking down at her phone. Cueball and Ponytail are standing next to each other.]
:Megan: Wow - according to the internet, we don't know the true name of the bear.
:Cueball: What?

:[Gretchen comes on-panel from the right.]
:Megan: Apparently there was a superstition that saying its name would summon it. "Bear" and "bruin" mean "the brown one." Its actual name has been lost.
:Cueball: Wow.
:Ponytail: Gretchen, is this for real?

:[Zoom-in on Gretchen.]
:Gretchen: Well, sort of
:Gretchen: The Proto-Indo-European root was *rkto-
:Gretchen: It was lost in the Germanic languages like English, but survived elsewhere, e.g. Greek "arktos" and Latin "ursus"

:[Back to the second panel, with Megan holding her phone down, Ponytail with her hands in the air, and Gretchen with her hand on her chin.]
:Megan: So could we figure out what the word would have been in English?
:Gretchen: Hmm. I mean, we'll never know, but given Germanic sound shifts, a reasonable guess might be "arth"?
:Ponytail: ''No!!''

:[The panel zooms in again to Gretchen.]
:Ponytail (off-panel): ''Stop! AAAAA!''
:Gretchen: What??
:Ponytail (off-panel): Don't ''say'' it!

:[Ponytail is holding her palms out. Megan is no longer in the panel.]
:Ponytail: What have you ''done''?
:Off-panel noise: <big>'''''ROAR'''''</big>
:Gretchen: Oh
:Gretchen: Oh no

{{comic discussion}}

[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring real people]]
[[Category:Language]]
[[Category:Animals]]

Talk:2343: Mathematical Symbol Fight

2020-08-10T16:19:34Z

108.162.219.168: octothorpe

Can I get aleph-null aleph-shaped throwing stars? [[User:LunarNapolean|LunarNapolean]] ([[User talk:LunarNapolean|talk]]) 20:18, 7 August 2020 (UTC)
: I'd prefer octothorpe throwing stars. [[Special:Contributions/108.162.219.168|108.162.219.168]] 16:19, 10 August 2020 (UTC)
Apologies to whoever added the "citation needed" that I stepped on. -- brad

That zeta looks conspicuously bad. I wonder if this comic will get a cleaned-up version uploaded. [[Special:Contributions/108.162.237.16|108.162.237.16]] 20:51, 7 August 2020 (UTC)

[[Megan]] usually has shoulder-length hair, so the person being attacked by Ponytail is probably not Megan... except in so far as all brunettes in this comic are called 'Megan'. [[User:LtPowers|LtPowers]] ([[User talk:LtPowers|talk]]) 20:53, 7 August 2020 (UTC)
:Is one of them [[Danish]]? And one of them Megan? [[Special:Contributions/172.69.33.121|172.69.33.121]] 22:49, 7 August 2020 (UTC)

I think Randall is underestimating the weapon utility of psi. There's a real-world martial arts [https://en.wikipedia.org/wiki/Sai_(weapon) weapon] that looks somewhat like it.[[Special:Contributions/172.69.68.197|172.69.68.197]] 22:04, 7 August 2020 (UTC)
:I think he’s also seriously underestimating the value of keeping your fingers attached to your hand. Swords have guards for a reason. I’d pick the contour integral over anything else there.

Considering the title text, a bass clef looks pretty formidable, close to a bat'leth. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 00:31, 8 August 2020 (UTC)
:Yes, but the treble clef is the one in the title text, and that’s nothing like a Klingon {{w|bat'leth}}. I removed the comment from the table. [[User:Adam1729|Adam1729]] ([[User talk:Adam1729|talk]]) 02:09, 8 August 2020 (UTC)
::If we're talking clefs/klingon weaponry, get on the viola clef. That's bat'leth AF. It's even known as a "K Clef" in some circles. You could do some pretty hefty damage with a viola clef.
::Or a viola...[[Special:Contributions/141.101.98.26|141.101.98.26]] 22:05, 9 August 2020 (UTC)

These “weapons” seem strangely appropriate for xkcd’s stick figures... -cpl
: Agreed :)

Are we sure White Hat is holding empty set? There don't appear to be points extending outside the circle in which case I think he's actually holding Theta -jc

Can I use the LaTeX mathwitch? [[Special:Contributions/141.101.98.26|141.101.98.26]] 10:03, 8 August 2020 (UTC)

First time editor here,hope I get the notation right! Question on the pi link to wikipedia: I put in the double link to the main page and the disambiguation because unfortunately https://en.wikipedia.org/wiki/Pi_(disambiguation)#Mathematics doesn't include the mathematical constant definition (though it is listed at the top of the page). Thoughts? [[User:Alan g|Alan g]] ([[User talk:Alan g|talk]]) 10:38, 8 August 2020 (UTC)

I think that’s the is proportional to” symbol rather than just alpha. They are similar but have different Unicode symbols. Thoughts?--[[Special:Contributions/141.101.98.222|141.101.98.222]] 12:01, 8 August 2020 (UTC)
:You're definitely correct. (They don't even look that similar...) It's the direct proportion symbol, not the symbol for Alpha.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 18:03, 8 August 2020 (UTC)
I don't think → is "implies", particularly as we've had ⇒ earlier. → is often used for "maps to", as in f: x → f(x) [[Special:Contributions/141.101.107.166|141.101.107.166]] 19:24, 8 August 2020 (UTC)
:→ and ⇒ often mean two different kinds of "implies". The single arrow is for the boolean operator that takes in two truth values and outputs a truth value. The double one is for "things on the left justify/prove things on the right", in somewhat of a metalanguage. Here's an example of two different ways of saying Modus Ponens with the operators: ((p→q) ∧p)→q vs p→q,p⇒q [[User:Alan g|Alan g]] ([[User talk:Alan g|talk]]) 03:52, 9 August 2020 (UTC)
Are we sure that is the multiplication sign (center dot)? The placement makes it seem more a decimal point. [[Special:Contributions/162.158.123.47|162.158.123.47]] 21:51, 8 August 2020 (UTC)
:Confusingly, math conventions in some countries use a low dot for multiplication, though it's not as common as it used to be. That's in addition to all the other things that bare dots can represent in math. Personally I can't "see" any particular set of semantics for that symbol, I just see a dot. [[Special:Contributions/162.158.186.136|162.158.186.136]] 22:51, 8 August 2020 (UTC)
We see a greater-than, but no less-than. Where would that appear? I think >≠<, in fact ><<, if wielded properly. Though if thrown, either/both could be a multi-use projectile... [[Special:Contributions/141.101.98.96|141.101.98.96]] 09:08, 9 August 2020 (UTC)
: Took me a little bit to figure out what you meant, but I think it hasn't been clarified which side is the point or sharp side, so until that is clarified "<"=">"

Anyone else think the title text is hinting at a pun? "I got scared because his weapon looked like treble" sort of thing?

Where is the opening parenthesis? [[Special:Contributions/172.69.33.223|172.69.33.223]] 21:43, 9 August 2020 (UTC)
: Here! (: [[Special:Contributions/162.158.154.131|162.158.154.131]] 09:33, 10 August 2020 (UTC)

If I could implement a line integral as a machine rather than a symbol, I'd use that to encircle my enemy. WIN! [[User:Cellocgw|Cellocgw]] ([[User talk:Cellocgw|talk]]) 13:15, 10 August 2020 (UTC)

i'm sure that the radix symbol could be used in a manner similar to sly cooper's crook [[Special: Contribuitions/138.186.224.65|138.186.224.65]] 13:32, 10 August 2020 (UTC)

== Would anyone else like to join me in creating an anti-Gamma interest group? ==

Just asking. [[Special:Contributions/172.69.33.223|172.69.33.223]] 21:47, 9 August 2020 (UTC)

428: Starwatching

2014-07-28T15:02:18Z

108.162.219.168: /* Explanation */

{{comic
| number = 428
| date = May 26, 2008
| title = Starwatching
| image = starwatching.png
| titletext = I always figured the word 'blog' would sound *less* silly as the years went by.
}}

==Explanation==
[[Megan]] and [[Cueball]] are {{w|stargazing}}. In the first two panels Cueball references a scene in the movie {{w|The Lion King}}, where the protagonist, Simba, remembers how his father, Mufasa, explained the night sky by saying, 'The great kings of the past are up there'. The quote in last panel is derived from a scene near the climax of the movie, where the spirit of Mufasa appears to Simba in the clouds, and speaks to him.

{{w|Cory Doctorow}} is a famous blogger who features is several of [[Randall]]'s [[:Category:Comics featuring Cory Doctorow|comics]]. A {{w|tag cloud}} is a list of links on the sidebar of a blog's layout that helps a reader find posts by type. Tags are shown to be larger the more posts have that tag applied to them.

Megan interrupts Cueball saying that she can't decide if Cueball needs to "get out more or less." If she were to say "get out more" she would be implying that he needs to spend time away from the computer so he stops seeing links between the real world and Cory Doctorow. If she says "get out less" she implies that he might scare normal people if he were to do what he does in front of them.

In the title text, Randall mentions that he feels that the word {{w|blog}}, a {{w|portmanteau}} and an {{w|Elision}} of 'web log', sounds silly, and has not become any less silly over the years, despite entering common usage.

==Transcript==
:[Cueball and Megan are lying on the ground stargazing]
:Cueball: Just look at those stars.

:Cueball: My father once told me that the great bloggers of the past are up there, watching over us.

:[Cueball sits up, and then stands up, stretching his arms in the air as if to encompass the whole night sky]
:Cueball: High above the blogosphere, a gap opens in the tag clouds. Cory Doctorow's voice booms forth...
:Megan: You need to get out either ''more'' or ''less''. I can't decide.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cory Doctorow]]

428: Starwatching

2014-07-28T15:01:47Z

108.162.219.168: /* Explanation */

{{comic
| number = 428
| date = May 26, 2008
| title = Starwatching
| image = starwatching.png
| titletext = I always figured the word 'blog' would sound *less* silly as the years went by.
}}

==Explanation==
{{incomplete|Edit for content/grammar/spelling. The explanation itself fairly well encompasses the matters in the comic that may need explaining.}}

[[Megan]] and [[Cueball]] are {{w|stargazing}}. In the first two panels Cueball references a scene in the movie {{w|The Lion King}}, where the protagonist, Simba, remembers how his father, Mufasa, explained the night sky by saying, 'The great kings of the past are up there'. The quote in last panel is derived from a scene near the climax of the movie, where the spirit of Mufasa appears to Simba in the clouds, and speaks to him.

{{w|Cory Doctorow}} is a famous blogger who features is several of [[Randall]]'s [[:Category:Comics featuring Cory Doctorow|comics]]. A {{w|tag cloud}} is a list of links on the sidebar of a blog's layout that helps a reader find posts by type. Tags are shown to be larger the more posts have that tag applied to them.

Megan interrupts Cueball saying that she can't decide if Cueball needs to "get out more or less." If she were to say "get out more" she would be implying that he needs to spend time away from the computer so he stops seeing links between the real world and Cory Doctorow. If she says "get out less" she implies that he might scare normal people if he were to do what he does in front of them.

In the title text, Randall mentions that he feels that the word {{w|blog}}, a {{w|portmanteau}} and an {{w|Elision}} of 'web log', sounds silly, and has not become any less silly over the years, despite entering common usage.

==Transcript==
:[Cueball and Megan are lying on the ground stargazing]
:Cueball: Just look at those stars.

:Cueball: My father once told me that the great bloggers of the past are up there, watching over us.

:[Cueball sits up, and then stands up, stretching his arms in the air as if to encompass the whole night sky]
:Cueball: High above the blogosphere, a gap opens in the tag clouds. Cory Doctorow's voice booms forth...
:Megan: You need to get out either ''more'' or ''less''. I can't decide.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cory Doctorow]]

428: Starwatching

2014-07-28T15:00:08Z

108.162.219.168: /* Transcript */

{{comic
| number = 428
| date = May 26, 2008
| title = Starwatching
| image = starwatching.png
| titletext = I always figured the word 'blog' would sound *less* silly as the years went by.
}}

==Explanation==
{{incomplete|Edit for content/grammar/spelling. The explanation itself fairly well encompasses the matters in the comic that may need explaining.}}

[[Megan]] and [[Cueball]] are {{w|stargazing}}. In the first two panels Cueball references a scene in the movie {{w|The Lion King}}, where the protagonist, Simba, remembers how his father, Mufasa, explained the night sky by saying, 'The great kings of the past are up there'. The quote in last panel is derived from a scene near the climax of the movie, where the spirit of Mufasa appears to Simba in the clouds, and speaks to him.

{{w|Cory Doctorow}} is a famous blogger who features is several of [[Randall]]'s [[:Category:Comics featuring Cory Doctorow|comics]]. A {{w|tag cloud}} is a list of links on the sidebar of a blog's layout that helps a reader find posts by type. Tags are shown to be larger the more posts have that tag applied to them.

Megan interrupts Cueball saying that she can't decide if Cueball needs to "get out more or less." If she were to say "get out more" she would be implying that he needs to spend time away from the computer so he stops seeing links between the real world and Cory Doctorow. If she says "get out less" she implies that he might scare normal people if he were to do what he does in front of them.

In the title text, Randall mentions that he feels that the word {{w|blog}}, a {{w|portmanteau}} and an {{w|Elision}} of 'web log', sounds silly, and has not become any less silly over the years, despite entering common usage. This is a common theme in Randall's writings and comics. For example xkcd's blog is called "[http://blag.xkcd.com/ The blag of the webcomic]", in mockery of the word blog.

==Transcript==
:[Cueball and Megan are lying on the ground stargazing]
:Cueball: Just look at those stars.

:Cueball: My father once told me that the great bloggers of the past are up there, watching over us.

:[Cueball sits up, and then stands up, stretching his arms in the air as if to encompass the whole night sky]
:Cueball: High above the blogosphere, a gap opens in the tag clouds. Cory Doctorow's voice booms forth...
:Megan: You need to get out either ''more'' or ''less''. I can't decide.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cory Doctorow]]

681: Gravity Wells

2014-07-10T13:43:09Z

108.162.219.168: /* Explanation */ Fixed some grammatical errors. ~Official.xain

{{comic
| number = 681
| date = December 28, 2009
| title = Gravity Wells
| image = gravity_wells.png
| titletext = This doesn't take into account the energy imparted by orbital motion (or gravity assists or the Oberth effect), all of which can make it easier to reach outer planets.
}}

The xkcd page links to [http://xkcd.com/681_large/ a much larger version].

==Explanation==
{{incomplete|Fix Grammar}}
The comic shows the gravitational potential (energy transferred per unit mass due to gravity) for the positions of each planet in the solar system -- including some moons and Saturn's rings. An object traveling along an upward slope loses energy, while an object traveling along a downward slope gains energy.

Escaping a planet or moon's orbit requires enough energy (e.g. by walking, jumping, or rocket) to reach the top of either peak that defines the edge of the well. The peak to the left indicates the minimum energy required to exit orbit. The peak to the right indicates the maximum energy required to exit orbit. In order to exit orbit with the minimum amount of energy, you would have to travel towards the center of the solar system; to exit orbit with the maximum amount of energy, you would have to travel away from the center of the solar system (the Sun). In reality, the strength of gravity decreases with distance from the planet. However, a comparison of energy expended to escape the gravitational pull allows for a simpler comparison between the objects.

The height of the graph is scaled to kilometers via the gravitational potential an object has at the given height assuming at a constant acceleration due to Earth's surface gravity. The {{w|Sun|Sun's}} gravity well is not shown in its entirety, but is just indicated on the far left as ''"Very very far down"''. Had it been shown in its full extent it would have made the rest of the drawing so small in comparison that it would have been unreadable. As the gravitational potential increases with distance from the sun the graph has a general upward slope. To rise out of each well on the diagram, and therefore escape the planets gravity, it would require the same energy required to rise out of a physical well of that depth at Earth's surface gravity.

The length of each gravity well is scaled to the diameter of the planet and the spacing between the planets is not to scale with distance from the sun. This is necessary to make the graph readable. Because the distance between the planets are condensed the gravitational potential, from the gravity pulling toward the sun, accumulates quicker. This is the reason for the large peeks between the planet. The moons shown in the chart are at the appropriate distance from their respective planets' gravity wells for their orbits.

Each planet is shown cut in half at the bottom of its well, with the depth of the well measured down to the planet's flat surface.

The Earth's gravity well's depth in the inset and in the main part of the comic don't match. This is most likely a mistake by Randall.

==== Planet-Moon systems ====
# {{w|Mercury_(planet)|Mercury}}
# {{w|Venus_(planet)|Venus}}
# {{w|Earth}}-{{w|Moon}}: The listed depth of the gravity well at Earth is mistakenly listed at 5 478 km (note the difference from the cutout value) and the Moon's is 288 km.
# {{w|Mars}}: The listed depth of the gravity well of Mars is 1 286 km.
# {{w|Jupiter}}-moon: Jupiter is so massive and dense that it is comparable in mass to a {{w|Brown dwarf}} which is the smallest kind of star. Saturn, while similar in size, is composed of much lighter gas material. Hence Saturn's mass and therefore its gravitational pull are much smaller. Had a few dozen times the mass of gasses contained in Jupiter condensed in that location, the gravitational pull would cause the pressure and temperature to increase to a level that is sufficient to ignite {{w|Nuclear fusion|nuclear fusion}}. Had that happen during creation of our solar system, we would have two {{w|Sun|Suns}} and our solar system would be a {{w|Binary system (astronomy)|Binary system}}. {{w|Ganymede_(moon)|Ganymede}}, {{w|Io_(moon)|Io}}, and {{w|Europa_(moon)|Europa}}, which are moons of Jupiter, are displayed as well.
# {{w|Saturn}}-moon: The diagram shows the position of the {{w|rings of Saturn}} in Saturn's gravity well. Saturn's rings start fairly near the planet and extend out quite far, therefore multiple stripes are shown in the figure. The rings are also shown in multiple colors and roughly match the observed colors from photos take by the {{w|Cassini–Huygens|Cassini spacecraft}} expedition as it passed Saturn. All of the colors of the planets and moons represent the predominant color of that object as observed from earth. {{w|Titan (moon)|Titan}}, a moon of Saturn, is displayed as well. The figures on Titan are sirens, a reference to Kurt Vonnegut's ''{{w|The Sirens of Titan}}''.
# {{w|Uranus}}: Notably absent is any "your-anus" jokes.
# {{w|Neptune}}: Megan's quote is a paraphrase of {{w|Carl Sagan|Carl Sagan's}} quote, "...but from a planet orbiting a star in a distant globular cluster, a still more glorious dawn awaits, not a sun-rise, but a galaxy rise." [http://www.youtube.com/watch?v=zSgiXGELjbc Video here]

==== Cut outs and sketches====
The following items are listed from top to bottom and left to right.

* Mars-moon: The Mars cutout shows the Mars moon system, including the moons Deimos and Phobos. The depth of the gravity well is listed at 1286 km.
* {{w|Deimos (moon)|Deimos}}: The gravity on Deimos, a moon of Mars, is so weak that a bike jump would be sufficient to escape its gravity.
* {{w|Phobos (moon)|Phobos}}: The gravity on Phobos, a moon of Mars, is so weak that you could launch a baseball into space simply by throwing it.
* Your mom-Local football team: The sketch next to Jupiter is playing on the classic "Yo Mama" joke. It combines "Yo Mama is so fat" and "Yo Mama is so horny". The sketch implies that she has a huge gravitational pull and has sex with an entire football team by demonstrating a football team being falling into her very deep gravity well. A "Yo Mama" joke also appears in comic [[89: Gravitational Mass]].
* Earth-Moon: The cut out shows the significant difference in strength between the {{w|gravity well}} of the Earth and the Moon. Cueball comments that the {{w|Apollo Lunar Module|Apollo Lunar Module}} was very small and the {{w|Saturn V}} rocket was very large because escaping the Earth's gravity well takes much more energy than escaping the Moon's. The cut out also shows that objects like the {{w|International_Space_Station|International Space Station}}, the {{w|Space shuttle|space shuttle}}, {{w|GPS satellite|GPS satellites}} and {{w|Geostationary orbit|geo-stationary satellites}} at their respective positions within Earth's gravity well. The depth of Earth's gravity well is listed correctly at 6 379 km (note the difference from the non-cutout number). The depth of the Moon's gravity well is listed at 288 km.

=== How to calculate gravity wells ===
The text near the bottom of Jupiter's gravity well explains that the depth of the well is mass-of-planet over radius-of-planet with newtons constant and 9.81 m/s² as constants, where 9.81 m/s² is the acceleration of a free falling body at Earth's gravity.

The calculation for a gravity well is:
:depth = (G * Planet-mass ) / (9.81 m/s2 * Planet-radius)
::where G is {{w|Isaac_Newton|Newton}}'s {{w|Gravitational_constant|gravitational constant}}, and
::9.81 m/s2 is the {{w|Acceleration|acceleration}} rate of a {{w|Gravity_of_Earth|free falling body on earth}} at sea level (g).

====Title text====
The title text indicates that the planets motion can affect the amount of energy for escape velocity. It is possible to change speed by using the planets orbital speed and gravity. This is know as a performing a slingshot or a {{w|Gravity assist|gravity assist}}, and is done to gain speed or to break when needed. On earth the same principle is used when launching rockets. Rockets are always launched in a eastward direction to make maximum use of the rotational energy of the earth. Launching rockets in a westward direction would require significant additional energy. Because of this most artificial satellites are flying east around the globe. Also, the use of rocket engines are more effective when used at a high speed. This is know as the {{w|Oberth effect}}. The use of engines are therefore more effective when used as part of a slingshot maneuver.

The size of the gravity-well as described in this comic is not accounting for these factors. Therefore leaving the solar system (or any of the gravity wells of the planets) could require less energy than described by the graph, assuming that the launch and slingshots are properly designed and executed.

==== Escape Velocities ====
The following table was adapted from the table in {{w|Escape velocity#List of escape velocities|Escape velocity}}, using ''h'' = ''V_e''^2 / 2''g'':
{| class="wikitable" border="1"
| Location || with respect to || Ve (km/s) || Well depth (km) ||
| Location || with respect to || Ve (km/s) || Solar well (Mm) || Total depth (Mm)
|-
| on the Sun, || the Sun's gravity: || 617.5 || 19,435,000 || || || || || || 19,435
|-
| on Mercury, || Mercury's gravity: || 4.3 || 942 ||
| at Mercury, || the Sun's gravity: || 67.7 || 233.6 || 235
|-
| on Venus, || Venus' gravity: || 10.3 || 5,407 ||
| at Venus, || the Sun's gravity: || 49.5 || 124.9 || 130
|-
| on Earth, || the Earth's gravity: || 11.2 || 6,393 ||
| at the Earth/Moon, || the Sun's gravity: || 42.1 || 90.3 || 97
|-
| on the Moon, || the Moon's gravity: || 2.4 || 294 ||
| at the Moon, || the Earth's gravity: || 1.4 || || 91
|-
| on Mars, || Mars' gravity: || 5 || 1,274 ||
| at Mars, || the Sun's gravity: || 34.1 || 59.3 || 61
|-
| on Jupiter, || Jupiter's gravity: || 59.5 || 180,400 ||
| at Jupiter, || the Sun's gravity: || 18.5 || 17.4 || 198
|-
| on Ganymede, || Ganymede's gravity: || 2.7 || 372 || || || || ||
|-
| on Saturn, || Saturn's gravity: || 35.6 || 64,600 ||
| at Saturn, || the Sun's gravity: || 13.6 || 9.43 || 74
|-
| on Uranus, || Uranus' gravity: || 21.2 || 22,907 ||
| at Uranus, || the Sun's gravity: || 9.6 || 4.7 || 28
|-
| on Neptune, || Neptune's gravity: || 23.6 || 28,400 ||
| at Neptune, || the Sun's gravity: || 7.7 || 3.02 || 31
|-
| on Pluto, || Pluto's gravity: || 1.2 || 73 || || || || ||
|-
|at Solar System galactic radius, || the Milky Way's gravity: || 525 || 14,000
|}

==Transcript==
:'''Main Text'''
:Gravity Wells scaled to Earth surface gravity
:This chart shows the "depth" of various solar system gravity wells.
:Each well is scaled such that rising out of a physical well of that depth — in constant Earth surface gravity — would take the same energy as escaping from that planet's gravity in reality.
:Each planet is shown cut in half at the bottom of its well, with the depth of the well measured down to the planet's ''flat'' surface.
:The planet sizes are to the same scale as the wells. Interplanetary distances are not to scale.
:Depth = (G × PlanetMass) / (g × PlanetRadius)
:G = Newton's constant
:g = 9.81 m/s2

:'''Planetary Descriptions'''
:To Sun, very very far down
:Mercury
:Venus
:Earth - 5,478 km
:Moon - 288 km
:Mars - 1,286 km
:Ganymede
:Io
:Jupiter
::[A drawing of a "very deep" gravity well, "Your mom" at the bottom, several member of "local football team" falling down towards her.]
::Jupiter is not much larger than Saturn, but much more massive. At its size, adding more mass just makes it denser due to the extra squeezing of gravity.
::If you dropped a few dozen more Jupiters into it, the pressure would ignite fusion and make it a star.
:Europa
:Titan
::Two figures: Weeoooeeoooeeooo
:Saturn
::Rings
:Uranus
:Neptune
::Megan: An even more glorious dawn awaits!

:'''Mars Inset'''
:[Mars gravity well, the Pathfinder probe on its surface, with its moons Deimos and Phobos as smaller gravity wells.]

:[Figure of a man (to scale) in Deimos's gravity well.]
:You could escape Deimos with a bike and a ramp.

:[Figure of a man (to scale) in Phobos's gravity well.]
:A thrown baseball could escape Phobos.

:'''Earth Inset'''
:[Zoomed-in view of Earth/moon gravity well, featuring the relative locations of the atmosphere, Low Earth Orbit, the International Space Station, the Space Shuttle, GPS satellites, and satellites in geosynchronous orbit.]
:Cueball: This is why it took a huge rocket to get to the moon but only a small one to get back.

:It takes the same amount of energy to launch something on an escape trajectory away from Earth as it would to launch it 6,000 km upward under constant 9.81 m/s2 Earth gravity.

:Hence, Earth's well is 6,000 km deep.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Large drawings]]
[[Category:Your Mom]]

Talk:456: Cautionary

2014-07-10T13:35:33Z

108.162.219.168: comment

Isn't 'Talk to your kids about...' from a famous Unilever ad? [[Special:Contributions/101.174.52.183|101.174.52.183]] 09:47, 2 June 2013 (UTC)

Is this Megan? Her hair seems awfully curly and it says she's his cousin. Is there an official transcript? [[User:Theo|Theo]] ([[User talk:Theo|talk]]) 20:46, 14 August 2013 (UTC)
:Official transcripts, if they do exist, do not contain names in general. These names are just an invention by some communities like this wiki. So, if you have a better stick figure which would match her, talk about this.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 21:16, 14 August 2013 (UTC)
::She is clearly not Megan. I propose to call her ''cousin''. [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 22:20, 13 October 2013 (UTC)
::There exists an official transcript for each comic, available to see in the page's source code. According to a comment in [[1037:_Umwelt]], Randall does apparently not type those, but is seemingly done by Davean, his friend maintaining the server. (Note: this is just a guess) [[User:Vgr|Vgr]] ([[User talk:Vgr|talk]]) 11:22, 22 October 2013 (UTC)
::I don't think that this is Megan either. I propose to call her Alice, though, in reference to cryptography. ~Official.xian

453: Upcoming Hurricanes

2014-07-10T13:03:24Z

108.162.219.168: Fixed a typo from "plains" to "planes" when talking about the Bermuda Triangle.

{{comic
| number = 453
| date = July 23, 2008
| title = Upcoming Hurricanes
| image = upcoming_hurricanes.png
| titletext = I'd like to see more damage assessments for hurricanes hitting New York and flooding Manhattan -- something like the 1938 Long Island Express, but aimed a bit more to the west. It's just a matter of time.
}}

==Explanation==
It must have been {{w|Atlantic hurricane season|hurricane season}} in the United States!

This comic gives some ideas on upcoming {{w|Tropical cyclone|hurricane}} paths on an unlabelled map that shows the region roughly between central {{w|Canada}} and northern {{w|Brazil}}. Red dotted lines indicates possible hurricane paths.

''Hurricane Where-The-Hell-Is-Bermuda'' enters from the east side of the map, wanders around the {{w|Atlantic Ocean}} in a scribble that seems to take the shape of an {{w|Ampersand}}. Then it goes north for a while, and then peters out without entering the {{w|Bermuda Triangle}}. The Bermuda Triangle is a location in the Atlantic Ocean loosely framed by the three corners {{w|Bermuda}}, {{w|Miami}} and {{w|Puerto Rico}}. The myth is that (too) many ships and planes get lost once they enter inside the area of this triangle and disappear without a trace. In this case the hurricane get lost before entering and can't even find the triangle.

''Hurricane Illinois-Has-It-Too-Easy'' comes from somewhere to the north-west, goes through {{w|Illinois}}, and then back to the north-west. This hurricane, while actually impossible, comes from Canada to strike {{w|Chicago}}, Illinois, before heading back to Canada. As hurricanes never hits Illinois this particular hurricane "think" they have too easy a time in this particular state. Interestingly enough, (though it did not affect the Chicago area or correspond with the path displayed in the comic), roughly one year later a {{w|Derecho|Super derecho}}, a storm resembling a hurricane or tropical storm in movement and form, struck central and South Illinois, in addition to much of {{w|Missouri}} and {{w|Kansas}}: {{w|May 2009 Southern Midwest derecho}}.

''Hurricane Freud'' starts in the {{w|Gulf of Mexico}}, draws a set of {{w|Testicle|balls}} to {{w|Florida|Florida's}} {{w|Penis|cock}}, and then {{w|Ejaculation|comes}} on land and stops. {{w|Sigmund Freud}} believed that accidental sexual expression was a reflection of the unconscious mind's sexual desires. The shape of the hurricane's path along the ''penis'' is taken as an example of this.

''Hurricane Screw-It-Let's-Just-Trash-Florida-Again'' comes from the east, starts to curve to the north, and then turns sharply to head straight for Florida and zigzag through it four times before dying out. Sticking out from the rest of the US, Florida is in a nice spot to get hurricanes from the East, South, and West. And with the state not being very high or wide, it is common for a hurricane to run over Florida, lose some strength, then rebuild strength over the hot waters in the Gulf of Mexico, only to do a U-turn and strike again. This is not exactly what happens with this particular hurricane, where it turns out into the Atlantic Ocean again each time. Just proving that it only wish to strike Florida!

''Hurricane Red'' and ''Hurricane Blue'', (which are the only hurricane path drawn in blue), are playing a game zipping in straight lines and right angles around {{w|Haiti}}, {{w|Jamaica}}, and {{w|Cuba}}. When ''Red'' successfully cuts off ''Blue'', the latter instantly dies, and then ''Red'' dies shortly thereafter. The game they play is the game of {{w|Tron_(video_game)#Light_Cycles|Light Cycles}} from the {{w|Tron_(video_game)|video game}} based on the movie {{w|Tron}}. ''Hurricane Blue'' lost because it crashed into the wall of light left by ''Hurricane Red's'' {{w|Light_Cycle#Light_cycles|light cycle}}.

''Hurricane Cos(x)'' forms a curve in the shape of a {{w|sinusoid}} above the bottom edge of the map. Its path resembles a {{w|sine}} wave. This kind of {{w|trigonometric functions}} can, however, both be expressed as sin(x) or cos(x), the latter being a {{w|cosine wave}}. They look exactly the same when there is no clearly defined coordinate system as in this case - see [[#Trivia|trivia]] below.

The title text refers to the {{w|1938 New England hurricane}} (also known as the Long Island Express), that caused $4.7 billion in damage in 2013 dollars. Had it been further west it could have caused more damage as the right side of a hurricane is stronger and more destructive than the left side as the winds on the right side push water inland. [[Randall]] asks for more damage assessments for such a hurricane that which would be able to flood {{w|Manhattan}} in {{w|New York}}. Almost prophetically for this comic, {{w|Hurricane Sandy}} did strike the {{w|New York metropolitan area|New York–New Jersey area}} only four years after this cartoon was published, causing an estimated $74 billion in damage.

The 1938 hurricane is also [[980:_Money/Transcript#Disasters|referenced]] in [[980: Money]] where it is calculated that it would have caused $78 billion had it happened in 2011. However, if that hurricane had taken the same turn as Sandy did, the cost today could have been a staggering $237 billion.

==Transcript==
:[An unlabelled map shows the region roughly between central Canada and northern Brazil. Dotted lines indicating hurricane paths cover the map, all red except Hurricane Blue which is blue. Each line is labelled - here follows the labels as they appear from the top and down:]
:Hurricane Where-the-Hell-Is-Bermuda
:Hurricane Illinois-Has-It-Too-Easy
:Hurricane Freud
:Hurricane Screw-It-Let's-Just-Trash-Florida-Again
:Hurricane Red
:Hurricane Blue
:Hurricane cos(x)

==Trivia==
*Regarding Hurricane cos(x):
**If {{w|Equator}} is the x-axis and the y-axis goes through the {{w|Prime meridian}} of {{w|Prime meridian (Greenwich)|Greenwich}} it would be possible to say if this was a true cosine function hurricane.
**A cosine would be 1 (the maximum value) at x=0 (i.e. the maximum value would occur under {{w|Greenwich}}), whereas a sine would be 0 at x=0.
**If it had been a basic cos(x) without any constants added, then it should have been centered along the equator instead of as it is - ranging from about 5.5° to 9.5° north {{w|latitude}}.
**But if the formula was of the form a*cos(b*x)+c with a, b and c given constant, the wave could move to the center of this range with c=7.5°. With the constant a=2° the wave would move between the max and minimum of the range, and then b could be chosen to make the wave length fit with the path shown in the map.

{{comic discussion}}
[[Category:Hurricanes]]
[[Category:Comics with color]]
[[Category:Penis]]