explain xkcd - User contributions [en]

Talk:349: Success

2025-04-15T16:03:15Z

162.158.216.201:

There is nothing in the comic about project management. The only point is that we start out assuming total success, then just hope we don't actually end up in a worse position, then that there is at least one working computer on the premises, and finally just by hoping to survive. The is purely a comment, taken to extremes, on the most likely result of an interaction with man and machine. As the 'incomplete' tag indicates, the BSD upgrade is just used as an example. The comic is not attempting to advocate for better project planning, no matter what anybody may think. [[Special:Contributions/108.162.219.223|108.162.219.223]] 18:45, 14 January 2014 (UTC)

What's incomplete about this explanation? It seems pretty thorough to me. [[Special:Contributions/199.27.128.136|199.27.128.136]]Evan

I find it funny that Megan says: "If we make it back alive, you're never upgrading anything again", implying that he would be allowed to if he dies, somehow.[[Special:Contributions/141.101.64.41|141.101.64.41]] 16:16, 7 March 2015 (UTC)
: It does not imply he would be allowed to if he dies. This is just how that phrase is commonly worded. The trope generally follows the form: "If we make it out of here alive, ________ never/ever again."{{unsigned|Flewk}}
: I think that's an example of denying the antecedent. [[Special:Contributions/108.162.212.227|108.162.212.227]] 17:43, 8 November 2017 (UTC)

Just wanted to point out that it doesn't say OpenBSD in the comic (which is implied in the explanation), just BSD, and if it did reference OpenBSD then another part of the explanation would be wrong (comic #518 mentions FreeBSD). [[Special:Contributions/188.114.99.41|188.114.99.41]] 14:00, 8 March 2015 (UTC)
:Read the title text. [[Special:Contributions/108.162.210.187|108.162.210.187]] 22:31, 29 July 2015 (UTC)

What are the odds of sharks actually attacking them? [[Special:Contributions/108.162.212.227|108.162.212.227]] 17:43, 8 November 2017 (UTC)
: The odds are zero, sharks don't attack people, that is a myth. I've swum with sharks hundreds of times and they are very shy creatures, easily startled. "Jaws" is NOT a documentary! [[User:The Cat Lady|--The Cat Lady]] ([[User talk:The Cat Lady|talk]]) 11:09, 14 August 2021 (UTC)
: we do not have enough data to form even a cogent guess. Most importantly, where are they? {{unsigned ip|172.69.33.149}}
:The trees look like they might be in a coniferous forest, meaning that they're somewhere in the lower latitudes of North America, Europe, or Asia. {{unsigned|Geography rulez}}

BSD stands for "Blue Screen of Death". [[User:Translated ORK|Translated ORK]] ([[User talk:Translated ORK|talk]]) 09:54, 15 April 2025 (UTC)
:And many other things, but it's {{w|Berkeley Software Distribution}} (a type of Unix) as encountered here. [[Special:Contributions/162.158.216.201|162.158.216.201]] 16:03, 15 April 2025 (UTC)

3071: Decay Chain

2025-04-04T08:42:54Z

162.158.216.201: /* Explanation */

{{comic
| number = 3071
| date = April 2, 2025
| title = Decay Chain
| image = decay_chain_2x.png
| imagesize = 312x595px
| noexpand = true
| titletext = If you have an old phone in a drawer, and you listen very carefully, you can occasionally hear the occasional tap of an emitted SIM card hitting the side of the drawer as the phone transmutes to a lower-end model.
}}

==Explanation==
{{incomplete|Created by an iPhone 6 that used to be an iPhone 13 - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic is a play on nuclear {{w|decay chains}}, the series of radioactive disintegrations that the nuclei of unstable atoms undergo. Example diagrams of such nuclear decay chains can be seen {{w|Decay_chain#Thorium_series|here}}. This comic suggests that as iPhones model iterations get higher (and typically, though not entirely, larger and [https://www.plug.tech/blogs/news/how-much-does-iphone-weigh heavier]), they, similarly to heavier chemical elements, become unstable and susceptible to decay into lesser models. Some isotopes of atoms decay into other isotopes, releasing particles in the process. This process is generally dictated by the number of the positively charged protons in an atomic nucleus, which dictate its chemical identity, and the neutrons, which keep the protons in as stable a clump as possible. Particular isotopes, increasingly so for heavier atoms, are known to be subject to one or more modes of {{w|nuclear decay}} in order to attain a more stable and simpler form, including by several such steps. This comic humorously explores how an iPhone would decay if decaying worked similarly, which is absurd as iPhones are large objects that do not suddenly and drastically change form.{{Citation needed}} (Although, almost all matter on Earth, including iPhones, contain ''some'' atoms that are radioactive and exhibit nuclear decay, mixed with a non-radioactive majority.)

The iPhones in the comic undergo two different types of decay, which mirror two types of nuclear decay:
* In {{w|alpha decay|alpha (''α'') decay}} (vertically downwards, in the diagram) the model number changes from a higher one to a model two steps lower, except for the step involving the iPhone X which apparently exists instead of a "9" model. This is equivalent to the change in {{w|atomic number}} when two protons, together with two neutrons, leave the nucleus in the form of a helium ion (He2+), known as an alpha particle. The atomic number of such atoms reduces by two and the {{w|mass number}} reduces by four (that held by the departing He2+). No evidence is given as to how the respective masses of the phones ''actually'' changes in this analogy.
* In {{w|Beta_decay#β−_decay|beta minus (''β''-) decay}} (a rightward-and-upward step) the iPhones undergo a version upgrade, but also the removal of a brand name modifier (usually denoting additional features included within the same model range), leaving them closer to that new range's most basic model. In elements, the effective conversion of a neutron into a proton and a free electron raises the atomic number by one by transforming a neutral particle to a positive one via emission of a small negatively charged {{w|beta particle}} (an electron), leaving the mass only slightly decreased. The decay step from the iPhone 13 Pro to the iPhone 14 Plus, which is missing a symbol, is clearly one of the ''β''- decay steps.

The specific reason for the decay chain stopping at iPhone '''7''' is unknown. A possible reason for this is because lithium, which is often used in phone batteries, has the stable isotope lithium-7. "Stable" may refer to the usability of the device in terms of whether or not it still receives security updates, but the iPhone 6s also received the [https://support.apple.com/en-us/100100 latest security patch] as of the time this comic was published. Apple has [https://www.bbc.com/news/technology-67911517 paid significant compensation] regarding one of their business practices of intentional obsolescence. Alternatively, [[Randall]] may be suggesting that models up to iPhone 7 were highly reliable, but that models beyond that have become ever more problematic - this would mirror the case of radioactive decay, where it is the higher numbered elements that are unstable.

(After alpha or beta decay, atoms may then emit {{w|gamma radiation}} (high-energy photons) as they rearrange their atomic state without changing their composition, but this process does not change the element in any meaningful way. It also will occur when neutron capture and/or atomic fission has occurred, which is generally considered outside the natural decay chain of any such isotope, and can also result from nuclear fusion. Beta decay also requires emission of an antineutrino, but that particle interacts so weakly with matter that it's undetectable except by extremely sensitive experimental equipment.)

The title text suggests that the "alpha particle" of the iPhone is a {{w|SIM card}}, and that alpha-decaying phones will emit one of these with each decay (despite few phones having more than two, and most working ones only having one, but perhaps that's part of the mystery of telephonic {{w|Nuclear transmutation|transmutation}}). The sound of an old phone, sitting in a drawer, ejecting the unnecessary SIM is likened to the slow click of a {{w|Geiger counter}} registering the decay particles ejected from a decaying radioisotope. Radioactive decay is a random and spontaneous process; without the sound, one would never otherwise know if the phone even ''had'' decayed without {{w|Schrödinger's cat|opening the drawer}} to find out.

A similar comparison between smartphones and physics processes (in this case in stars) happened in [[1422: My Phone is Dying]].

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

[A flowchart with arrows leading from a circle with the words "iPhone 16 Pro Max", to circles with other iPhone names, eventually leading to a circle with the words "iPhone 7"]

:[Caption below the panel:]
:Physicists believe that an iPhone 16 Pro Max will, if left alone long enough, eventually decay into an iPhone 7, the heaviest stable model.

{{comic discussion}}

[[Category:Smartphones]]
[[Category:Physics]]

3071: Decay Chain

2025-04-04T08:41:04Z

162.158.216.201: /* Explanation */

{{comic
| number = 3071
| date = April 2, 2025
| title = Decay Chain
| image = decay_chain_2x.png
| imagesize = 312x595px
| noexpand = true
| titletext = If you have an old phone in a drawer, and you listen very carefully, you can occasionally hear the occasional tap of an emitted SIM card hitting the side of the drawer as the phone transmutes to a lower-end model.
}}

==Explanation==
{{incomplete|Created by an iPhone 6 that used to be an iPhone 13 - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic is a play on nuclear {{w|decay chains}}, the series of radioactive disintegrations that the nuclei of unstable atoms undergo. Example diagrams of such nuclear decay chains can be seen {{w|Decay_chain#Thorium_series|here}}. This comic suggests that as iPhones model iterations get higher (and typically, though not entirely, larger and [https://www.plug.tech/blogs/news/how-much-does-iphone-weigh heavier]), they, similarly to heavier chemical elements, become unstable and susceptible to decay into lesser models. Some isotopes of atoms decay into other isotopes, releasing particles in the process. This process is generally dictated by the number of the positively charged protons in an atomic nucleus, which dictate its chemical identity, and the neutrons, which keep the protons in as stable a clump as possible. Particular isotopes, increasingly so for heavier atoms, are known to be subject to one or more modes of {{w|nuclear decay}} in order to attain a more stable and simpler form, including by several such steps. This comic humorously explores how an iPhone would decay if decaying worked similarly, which is absurd as iPhones are large objects that do not suddenly and drastically change form.{{Citation needed}} (Although, almost all matter on Earth, including iPhones, contain ''some'' atoms that are radioactive and exhibit nuclear decay, mixed with a non-radioactive majority.)

The iPhones in the comic undergo two different types of decay, which mirror two types of nuclear decay:
* In {{w|alpha decay|alpha (''α'') decay}} (vertically downwards, in the diagram) the model number changes from a higher one to a model two steps lower, except for the step involving the iPhone X which apparently exists instead of a "9" model. This is equivalent to the change in {{w|atomic number}} when two protons, together with two neutrons, leave the nucleus in the form of a helium ion (He2+), known as an alpha particle. The atomic number of such atoms reduces by two and the {{w|mass number}} reduces by four (that held by the departing He2+). No evidence is given as to how the respective masses of the phones ''actually'' changes in this analogy.
* In {{w|https://en.wikipedia.org/wiki/Beta_decay#%c3%9f−_decay|beta minus (''β''-) decay}} (a rightward-and-upward step) the iPhones undergo a version upgrade, but also the removal of a brand name modifier (usually denoting additional features included within the same model range), leaving them closer to that new range's most basic model. In elements, the effective conversion of a neutron into a proton and a free electron raises the atomic number by one by transforming a neutral particle to a positive one via emission of a small negatively charged {{w|beta particle}} (an electron), leaving the mass only slightly decreased. The decay step from the iPhone 13 Pro to the iPhone 14 Plus, which is missing a symbol, is clearly one of the ''β''- decay steps.

The specific reason for the decay chain stopping at iPhone '''7''' is unknown. A possible reason for this is because lithium, which is often used in phone batteries, has the stable isotope lithium-7. "Stable" may refer to the usability of the device in terms of whether or not it still receives security updates, but the iPhone 6s also received the [https://support.apple.com/en-us/100100 latest security patch] as of the time this comic was published. Apple has [https://www.bbc.com/news/technology-67911517 paid significant compensation] regarding one of their business practices of intentional obsolescence. Alternatively, [[Randall]] may be suggesting that models up to iPhone 7 were highly reliable, but that models beyond that have become ever more problematic - this would mirror the case of radioactive decay, where it is the higher numbered elements that are unstable.

(After alpha or beta decay, atoms may then emit {{w|gamma radiation}} (high-energy photons) as they rearrange their atomic state without changing their composition, but this process does not change the element in any meaningful way. It also will occur when neutron capture and/or atomic fission has occurred, which is generally considered outside the natural decay chain of any such isotope, and can also result from nuclear fusion. Beta decay also requires emission of an antineutrino, but that particle interacts so weakly with matter that it's undetectable except by extremely sensitive experimental equipment.)

The title text suggests that the "alpha particle" of the iPhone is a {{w|SIM card}}, and that alpha-decaying phones will emit one of these with each decay (despite few phones having more than two, and most working ones only having one, but perhaps that's part of the mystery of telephonic {{w|Nuclear transmutation|transmutation}}). The sound of an old phone, sitting in a drawer, ejecting the unnecessary SIM is likened to the slow click of a {{w|Geiger counter}} registering the decay particles ejected from a decaying radioisotope. Radioactive decay is a random and spontaneous process; without the sound, one would never otherwise know if the phone even ''had'' decayed without {{w|Schrödinger's cat|opening the drawer}} to find out.

A similar comparison between smartphones and physics processes (in this case in stars) happened in [[1422: My Phone is Dying]].

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

[A flowchart with arrows leading from a circle with the words "iPhone 16 Pro Max", to circles with other iPhone names, eventually leading to a circle with the words "iPhone 7"]

:[Caption below the panel:]
:Physicists believe that an iPhone 16 Pro Max will, if left alone long enough, eventually decay into an iPhone 7, the heaviest stable model.

{{comic discussion}}

[[Category:Smartphones]]
[[Category:Physics]]

1606: Five-Day Forecast

2025-04-02T11:33:02Z

162.158.216.201: /* Explanation */

{{comic
| number = 1606
| date = November 20, 2015
| title = Five-Day Forecast
| image = five_day_forecast.png
| titletext = You know what they say--if you don't like the weather here in the Solar System, just wait five billion years.
}}

==Explanation==
{{w|Weather forecasting}} is an extremely difficult task, even if it is only for five days. In numerical models, extremely small errors in initial values double roughly every five days for variables such as temperature and wind velocity. So most {{w|Meteorology#Meteorologists|meteorologists}} provide us with only a five-day forecast.

In this comic [[Randall]] takes this to the extreme by first showing a '''Five-Day Forecast''' and then progressing to five-month, year, million, billion and finally trillion-year forecasts, leading to {{tvtropes|WeirdWeather|weather patterns that we don't regularly see.}}

Since the first weather symbol is the same in all six rows, we can assume it indicates the weather today and not tomorrow, in a trillion years, etc. It is only in the second panel of each row that time has passed per the row's label. Consequently, the last column gives the predictions for four days, four months, ..., four trillion years from today.

When moving past the five-day prediction, the forecast is just a qualified guess based on the time of year. In a month it is Christmas as shown in the second panel of the second row. Then it is January and February so snow is likely, but certainly not something that happens on all days of a winter month.

Looking at the five-year forecast, guesses are made as to what the weather will be like at the same time of year. For these first three predictions the weather symbols are all of the same three types: Sun, clouds and some kind of {{w|precipitation}}, rain or snow, with the temperature ranging from 21 to 44 °F (-6.1 to 6.6 °C) - late-{{w|Autumn#Date definitions|autumn/fall}} (perhaps early-{{w|Winter#Astronomical and other calendar-based reckoning|winter}}) temperatures.

Then we go into the far future, jumping a million years from panel to panel. But still the weather symbols stay the same. In 3 million years, however, aliens (or advanced humans) attack with energy beams from {{w|flying saucers}}. They are absent a million years later, or at least not actively attacking in any visible way during this later snapshot. The temperature range remains the same across the panels except that it rises to 52 °F (11 °C), a possible reference to global warming, in one panel, and while the attack is going on it rises to 275 °F (135 °C).

Once we get to the billion-year mark it actually becomes more meaningful to try to predict the "weather", because now we reach the times when the {{w|Sun}} begins to change. Although the Sun will continue to burn hydrogen for about 5 billion years yet (while in its {{w|Sun#Main sequence|main sequence|}}), it will grow in diameter as it begins to exhaust its supply of fuel. The core will contract to increase the temperature, and the outer layer will then compensate by expanding slightly. This is what is indicated in panels two and three, where the color of the Sun changes towards red as the surface becomes cooler as it expands away from the center of the Sun. The temperature will rise on Earth as indicated in the panels (105 °F = 40.5 °C and 371 °F = 188 °C). The temperature will get hot enough in about [http://phys.org/news/2015-02-sun-wont-die-billion-years.html a billion years] that the Earth's oceans will boil away.

Once it {{w|Sun#After core hydrogen exhaustion|no longer has enough hydrogen}}, the Sun will expand into a {{w|red giant}}. This should not happen until around {{w|Sun#Composition|five billion years from now}}, but in the forecast it is indicated to happen in only three. Maybe this is Randall taking liberties to show what happens during this phase, which would not fit into a four-billion-year forecast. Alternatively it just indicates how uncertain these kinds of forecasts are, or a statement that we may not know for certain that it will take five not three billion years, nor what toll other influences (such as attacking aliens) might take on the Sun.

In any case, the fourth panel shows the temperature at Earth's position inside the red giant Sun. The color of the panel indicates that we are inside the Sun. The temperature is 71,488,106 degrees Fahrenheit (39,715,597 degrees Celsius). The current temperature of the center of the Sun is "only" 27 million degrees Fahrenheit (15 million degrees Celsius), and although that may rise by a factor of ten during {{w|Stellar nucleosynthesis|helium fusion}}, that will only be at the very core and not out in the solar atmosphere reaching out to Earth. Here the temperature would only be of the order of thousands of degrees Fahrenheit, since the Sun's outer temperature decreases as it increases its diameter. So this panel's temperature also makes little sense by current understanding. It may involve some ambiguities regarding what the forecast means; the edge of the red giant Sun is predicted to be somewhere near the current orbit of Earth, but the position of the Earth could change. The most likely prediction at the moment is for Earth to move outward but, if the planet is engulfed by the Sun, it would spiral inward, and at some point fall apart. So in some sense "here" for the forecast could become a position deep inside the Sun, where core temperatures could reach 100 million Kelvin. The temperatures shown are unreasonably precise; they probably should have only two or at most three significant figures, if not for the running theme of escalating levels of prescience (enough to predict a future attack by flying saucers, etc).

The red giant phase lasts only half a million years, so a billion years after the Sun has been a red giant its outer atmosphere will definitely have disappeared, leaving only a dim, cool {{w|white dwarf}} to cool down. Given Randall's version of this time schedule, then it will have had about a billion years to cool down, but would still likely be the brightest object in the sky as seen from where the Earth once was. It is not shown in the last panel, where we just see other stars of the Galaxy. The temperature is down to that of the {{w|Cosmic microwave background|background radiation}}. Today this radiation has a temperature of 2.72548 kelvin = -270.4245 °C = -454.7641 °F. That is a few degrees F colder than what is shown in the comic, which states the temperature is -452 °F = 4.26 kelvin. This higher temperature may have been chosen to reflect that even the light from other stars would increase the actual temperature.

In the last panel with trillions of years, we jump right past the Sun's red giant phase to a panel looking much like the one after five billion years with only other stars. Over the next three trillion years the stars become fewer and fewer and dimmer and dimmer as they run out of fuel and fewer new stars form. After four trillion years the background temperature decreases one degree to -453 °F as the universe keeps expanding and the wavelength of the radiation does the same, thus decreasing its temperature.

The title text is a play on comments referring to fast-changing weather on a more ordinary human timescale, such as Mark Twain's quip, "If you don't like the weather in New England now, just wait a few minutes."

A ten-day forecast was used in [[1245: 10-Day Forecast]]. In [[1379: 4.5 Degrees]], Randall looked at the weather over long periods of time as well. in [[1643: Degrees]] he addressed Celsius vs. Fahrenheit for measuring temperature.

===Image using Celsius===

There is a different user-made version for the picture, using [[3001|Celsius]] instead of Fahrenheit, [[:File:five_day_forecast_Celsius.png|in this image link]]. (For a version that also uses Kelvin, [[:File:five_day_forecast_Celsius+Kelvin.png|click here]].)

==Transcript==
:[A grid with six rows of five columns, where each row is labeled to the left. For each of the 30 squares a temperature is given in Fahrenheit at the top left. The rest of the square represents the weather as in a weather forecast (or some other relevant items for the comic), mainly in bright colors. Below are the six labels given above each of their five weather symbols with temperature given below these symbols description.]

:'''Your 5-day forecast'''
:[A bright yellow sun.]
:38°F
:[A grey cloud.]
:41°F
:[A grey cloud with six lines of blue raindrops below.]
:36°F
:[A grey cloud in front of a yellow sun.]
:40°F
:[A bright yellow sun.]
:44°F

:'''Your 5-month forecast'''
:[A bright yellow sun.]
:38°F
:[A green Christmas tree with red presents beneath it.]
:29°F
:[A grey cloud with four snowflakes below.]
:21°F
:[A grey cloud with four snowflakes below.]
:24°F
:[A grey cloud.]
:35°F

:'''Your 5-year forecast'''
:[A bright yellow sun.]
:38°F
:[A grey cloud.]
:25°F
:[A bright yellow sun.]
:36°F
:[A grey cloud with six lines of blue raindrops below.]
:37°F
:[A bright yellow sun.]
:41°F

:'''Your 5-million-year forecast'''
:[A bright yellow sun.]
:38°F
:[A bright yellow sun.]
:52°F
:[A grey cloud.]
:40°F
:[Two red flying saucers (with bright domes) are shooting energy beams downwards. One of the beams seems to impact with something at the bottom of the panel, which then explodes. Two plumes of smoke rises up from below, drifting to the right.]
:275°F
:[A grey cloud in front of a yellow sun.]
:40°F

:'''Your 5-billion-year forecast'''
:[A bright yellow sun.]
:38°F
:[A larger orange sun.]
:105°F
:[A very large red sun.]
:371°F
:[A pale yellow panel with no drawing.]
:71,488,106°F
:[A night sky with many bright stars.]
:-452°F

:'''Your 5-trillion-year forecast'''
:[A bright yellow sun.]
:38°F
:[A night sky with many bright stars.]
:-452°F
:[A night sky with many stars.]
:-452°F
:[A night sky with fewer not so bright stars.]
:-452°F
:[A night sky with few dim stars.]
:-453°F

{{comic discussion}}

[[Category:Comics with inverted brightness]]
[[Category:Comics with color]]
[[Category:Science]]
[[Category:Space]]
[[Category:Astronomy]]
[[Category:Weather]]
[[Category:Aliens]]
[[Category:Christmas]]