explain xkcd - User contributions [en]

2492: Commonly Mispronounced Equations

2021-07-22T10:54:05Z

Xavier Combelle:

{{comic
| number = 2492
| date = July 21, 2021
| title = Commonly Mispronounced Equations
| image = commonly_mispronounced_equations.png
| titletext = "Epsihootamoo doopsiquorps" --the Schrödinger equation for the hydrogen atom
}}

==Explanation==
{{incomplete|Created by a LAGRONJ EYSIBARYMOODMOOSIOYLERSIBRYMOOAMOOBAMOOSIMASIBRSIQORTFAHMOOVYFAHMOOVY. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic is a collection of famous physical and mathematical equations, along with their "correct" pronunciations. Equations are normally voiced out loud either by their names ("Mass–energy equivalence") or by saying the parts out loud using normal linguistic rules ("E equals M C squared"). This comic instead asserts that equations are meant to be said out loud like words, using their own set of phonic rules.
This premise is obviously absurd, and may make this comic an attempt by Randall to troll people who insist on trying to explain all of his comics.

The pronunciation given for F=MA is the same as the actual pronunciation of FEMA, the acronym for the Federal Emergency Management Agency.

List of equations:
* {{w|Newton%27s_law_of_universal_gravitation|Newton's law of universal gravitation}}
* {{w|Mass%E2%80%93energy_equivalence|Mass-energy equivalence}}
* {{w|Pythagorean_theorem|Pythagorean theorem}}
* {{w|Area_of_a_circle|Area of a circle}}
* {{w|Entropy_(information_theory)|Entropy}}
* {{w|Ideal_gas_law|Ideal gas law}}
* {{w|Euler%27s_identity|Euler's identity}}
* {{w|Newton%27s_laws_of_motion|Newton's laws of motion}}
* {{w|Wave_equation|Wave equation}} (c should be c<sup>2</sup>
* {{w|Difference_quotient|Difference quotient}}
* {{w|Quadratic_equation|Quadratic equation}}
* {{w|Schrödinger_equation|Schrödinger equation}}

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

{{comic discussion}}
[[Category:Physics]]
[[Category:Math]]
[[Category: Language]]

2492: Commonly Mispronounced Equations

2021-07-22T10:30:03Z

Xavier Combelle: /* Explanation */

{{comic
| number = 2492
| date = July 21, 2021
| title = Commonly Mispronounced Equations
| image = commonly_mispronounced_equations.png
| titletext = "Epsihootamoo doopsiquorps" --the Schrödinger equation for the hydrogen atom
}}

==Explanation==
{{incomplete|Created by a LAGRONJ EYSIBARYMOODMOOSIOYLERSIBRYMOOAMOOBAMOOSIMASIBRSIQORTFAHMOOVYFAHMOOVY. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic is a collection of famous physical and mathematical equations, along with their "correct" pronunciations. Equations are normally voiced out loud either by their names ("Mass–energy equivalence") or by saying the parts out loud using normal linguistic rules ("E equals M C squared"). This comic instead asserts that equations are meant to be said out loud like words, using their own set of phonic rules.
This premise is obviously absurd, and may make this comic an attempt by Randall to troll people who insist on trying to explain all of his comics.

The pronunciation given for F=MA is the same as the actual pronunciation of FEMA, the acronym for the Federal Emergency Management Agency.

List of equations:
* {{w|Newton%27s_law_of_universal_gravitation|Newton's law of universal gravitation}}
* {{w|Mass%E2%80%93energy_equivalence|Mass-energy equivalence}}
* {{w|Pythagorean_theorem|Pythagorean theorem}}
* {{w|Area_of_a_circle|Area of a circle}}
* {{w|Entropy_(information_theory)|Entropy}}
* {{w|Ideal_gas_law|Ideal gas law}}
* {{w|Euler%27s_identity|Euler's identity}}
* {{w|Newton%27s_laws_of_motion|Newton's laws of motion}}
* {{w|Wave_equation|Wave equation}} (c should be c<sup>2</sup> and x and t should be exchanged in this comic)
* {{w|Difference_quotient|Difference quotient}}
* {{w|Quadratic_equation|Quadratic equation}}
* {{w|Schrödinger_equation|Schrödinger equation}}

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

{{comic discussion}}
[[Category:Physics]]
[[Category:Math]]
[[Category: Language]]

2121: Light Pollution

2019-03-08T21:29:24Z

Xavier Combelle: Undo revision 170816 by 162.158.106.6 (talk) vandalism

{{comic
| number = 2121
| date = March 8, 2019
| title = Light Pollution
| image = light_pollution.png
| titletext = It's so sad how almost no one alive today can remember seeing the galactic rainbow, the insanity nebula, or the skull and glowing eyes of the Destroyer of Sagittarius.
}}

==Explanation==
{{incomplete|Created by the DESTROYER OF SAGITTARIUS. Needs flushing out and reference to light pollution with regard to astronomy. Could use list of actual things that are no longer visible in the sky anywhere due to industrialization. Maybe a list of what any of these things could be reference to (The fake things). Please mention here why else this explanation isn't complete. Do NOT delete this tag too soon.}}

This comic shows how {{w|Light pollution|light pollution}} in cities affect what you can see from the night sky. The first three panels are real-life examples of what you could see from the sky inside a large city, in the suburbs and far away from light pollution. These panels roughly correlate on the {{w|Bortle Scale}} to 8-9 (city), 5-6 (suburbs) and 2-3 (remote area).

The last panel contrasts these for comedic effect with fake things in the sky that are not actually present in the night sky. "{{w|Celestial spheres|Crystal spheres}}" is an ancient theory about the heavens and what it was that held up the stars, before it was commonly accepted that space could be made of hard vacuum.

The title text starts off sounding like a legitimate statement about light pollution. It is common to remark that the vast majority of people never see things in the night sky that were commonly seen by our ancestors every night prior to industrialization, such as the {{w|Milky Way}} or now-obscure phenomena such as {{w|Zodiacal light}}, {{w|Airglow}} or {{w|Gegenschein}}. The title text then further adds to the humor of the last panel by describing non-existent features, many of which could be references to {{w|H. P. Lovecraft}}. He often refers to beasts the possible size that “The Destroyer of Sagittarius” would have to be. He also often speaks of insanity and color, connecting the two.

For non astronomers, {{w|Sagittarius (constellation)|Sagittarius}} is one of the constellations of the zodiac and {{w|Sagittarius A*}} a black hole at the center of the {{w|Milky Way}} inside of that constellation.

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

:[Four views of the night sky are shown among each other. The text on top reads:]
:'''Light Pollution and the Disappearing Night Sky'''

:[The first view shows only a few bright stars visible on a fairly light gray-brownish background. The inline text on the left top is:]
:High Light Pollution
:(Cities)

:[On the second view more stars are appearing and some faint blurry white clouds on a dark-gray background are visible.]
:Moderate Light Pollution
:(Suburbs)

:[A lot of stars, even partly colored, and a clear image of many clouds on a dark background are shown.]
:Low Light Pollution
:(Very remote areas)

:[The last image shows the same region as above but with even more exposed stars and clouds, the colors are also more explicit. A faint lattice of triangles overlaying the image to its full extent and three ghastly silhouettes of sailships are shown embedded in clouds. The text on the top left reads:]
:No Light Pollution
:(How the sky should look)
:[Four arrows are pointing to some triangles:]
:Lattice of the crystal spheres
:[Three arrows are indicating the sailships:]
:Ships of the Sky King

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Astronomy]]

2115: Plutonium

2019-02-22T18:17:54Z

Xavier Combelle: vandalism

{{comic
| number = 2115
| date = February 22, 2019
| title = Plutonium
| image = plutonium.png
| titletext = It's like someone briefly joined the team running the universe, introduced their idea for a cool mechanic, then left, and now everyone is stuck pretending that this wildly unbalanced dynamic makes sense.
}}

==Explanation==
{{incomplete|Created by a SENTIENT POWER ORB. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic pokes fun at the properties of plutonium, claiming that it is so unrealistically powerful that it may as well be random sci-fi jargon. Indeed, the ability for a metal to radiate free energy sounds impossible. This is reflected by Megan and Hairy treating Cueball's idea as a practical joke.

There are devices that need substantial electrical power over long time – in the order of decades – but local sources of energy are insufficient or unavailable, yet constructing a power line or resupplying them with some power source (like fuel, fresh chemical batteries etc.) is either impossible or overly costly. Such devices include maritime beacons and automatic weather or science stations located in remote areas, and, most importantly, deep space probes. Probes sent beyond Jupiter cannot effectively rely on photovoltaic panels for energy, because the large distance to the Sun means that the amount of solar radiation per unit of area is very low, requiring impractically large (and thus heavy) panels to provide enough energy. Also, carrying a lot of fuel also adds mass to the probe.

Instead, such devices usually use {{W|radioisotope thermoelectric generator}}s (RTGs). In an RTG the natural radioactive decay of some unstable isotope (such as Plutonium-238 or Strontium-90) produces a lot of heat, which is then used to generate energy using {{W|thermocouple}}s, which generate electricity directly from heat by employing the {{W|thermoelectric effect}}.

The title text references video game development, and how after joining a team and implementing a mechanic, a dev can leave, and give others working on it little or no knowledge of how to fix a specific design.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Megan, Hairy, Cueball, and Ponytail are talking.]
:Megan: How will we keep the spacecraft supplied with heat and electricity?
:Cueball: We could use a power orb. They give off thousands of watts 24/7.
:Megan: Huh? How do you recharge it.
:Cueball: You don't. It's just made of a metal that emits energy.
:Megan: OK, come on.
:Hairy: Can we please be serious here?
:[Caption below the panel:]
:For something that's real, plutonium is so unrealistic.

{{comic discussion}}

Talk:2107: Launch Risk

2019-02-04T18:55:21Z

Xavier Combelle:

Gave a brief explanation, but I think it would be good to mention probability based logical fallacies and https://what-if.xkcd.com/55/. Don’t know how to link without it looking bad. This is my first page! [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 17:28, 4 February 2019 (UTC)

Revised to a more extensive explanation including the fallacy that the second astronaut apparently realizes in mid-reply. [[User:SteveMB|SteveMB]] ([[User talk:SteveMB|talk]])

What are the odds that one or both astronauts are female? I see "he" being used to refer to the second astronaut, but we don't actually know the sex of either one. [[Special:Contributions/162.158.74.135|162.158.74.135]] 17:56, 4 February 2019 (UTC)
: Fixed [[Special:Contributions/108.162.246.95|108.162.246.95]] 18:07, 4 February 2019 (UTC)

This seems wrong, at least with the lightning explanation. I believe the joke is that since he already is an astronaut, being hit by lightning doesn’t seem unlikely. [[User:Netherin5|Netherin5]] ([[User talk:Netherin5|talk]]) 18:03, 4 February 2019 (UTC)

Would be nice to add something about risk perception of common vs. uncommon and dramatic vs. more mundane seeming events. e.g. in US, lifetime chance of death from flu, 1 in 63; from automobile accident 1 in 84; from lightning 1 in 79,746; from shark attack, 1 in 3,748,067 https://www.floridamuseum.ufl.edu/shark-attacks/odds/compare-risk/death/ [[Special:Contributions/108.162.245.166|108.162.245.166]] 18:52, 4 February 2019 (UTC)

The risk to be killed as an astronaut should be add somewhere (it is easy to find number of death/total number of astronaut) if someone want to make the morbid calculation. [[User:Xavier Combelle|Xavier Combelle]] ([[User talk:Xavier Combelle|talk]]) 18:55, 4 February 2019 (UTC)

Talk:1885: Ensemble Model

2017-09-05T02:35:56Z

Xavier Combelle:

Where's the guy who knows how to make tables? A table would be good for this article, so we could explain each joke scenario. [[Special:Contributions/172.68.26.5|172.68.26.5]] 15:41, 4 September 2017 (UTC)
:I don't like tables when the text in the data cells is more than only a few words. That's bad layout. I have entered all the text from the list into separate headers for the appropriate floating text layout.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:39, 4 September 2017 (UTC)
Might be worth mentioning the context for this comic; viz. the approach of hurricane Irma, with a wide range of predictions as to where it might end up (and which areas it would hit), making weather modeling (and hurricane modeling in particular) – and the uncertainties involved – topical. It's clear to us now, but won't be clear to readers a few years from now. [[User:Pelosujamo|Pelosujamo]] ([[User talk:Pelosujamo|talk]]) 01:37, 5 September 2017 (UTC)
:Wait - you mean it's not related to Harvey? (In other words, I'm not part of the "us" you speak about.) -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 02:17, 5 September 2017 (UTC)global warming https://www.explainxkcd.com/wiki/index.php/1885:_Ensemble_Model

I would say that one the idea of randall is related to point the change climate denier invalid reasoning that despite all scenario of global warning show increase of temperature, the fact that none of each is very likely to be wrong then all are wrong. (The fallacy is in the last then: the reunion of little probability can lead to high confidence or a the reunion of sum of various probable things can lead to absolutely certain ) [[User:Xavier Combelle|Xavier Combelle]] ([[User talk:Xavier Combelle|talk]]) 02:35, 5 September 2017 (UTC)