https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=162.158.63.154&feedformat=atomexplain xkcd - User contributions [en]2020-09-19T01:40:15ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2295:_Garbage_Math&diff=1908462295: Garbage Math2020-04-17T22:43:28Z<p>162.158.63.154: Edited sum to product in chart for multiplication.</p>
<hr />
<div>{{comic<br />
| number = 2295<br />
| date = April 17, 2020<br />
| title = Garbage Math<br />
| image = garbage_math.png<br />
| titletext = 'Garbage In, Garbage Out' should not be taken to imply any sort of conservation law limiting the amount of garbage produced.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a ZILOG Z80. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}<br />
This comic explains the "{{w|garbage in, garbage out}}" concept using arithmetical expressions. Just like the comic says, if you get garbage in any part of your workflow, you get garbage as a result.<br />
<br />
Some of these rules correspond to the rules of {{w|floating point arithmetic}}, while others may be inspired by the rules of {{w|Propagation_of_uncertainty#Example_formulae| propagation of uncertainty}} where a "garbage" number would correspond to an estimate with a high degree of uncertainty, and the uncertainty of the result of arithmetic operations will tend to be dominated by the term with the highest uncertainty. The rule about N pieces of independent garbage reflects the {{w|central limit theorem}} and how it predicts that the uncertainty (or {{w|standard error}}) of an estimate will be reduced when independent estimates are averaged. <br />
<br />
This comic is not related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}, breaking the streak of comics preceding this on [[:Category:COVID-19|topics relating to COVID-19]], after (rather appropriately) 19 comics (not counting the [[2288: Collector's Edition|April Fools' comic]]).<br />
<br />
This comic is about the propagation of errors in numerical analysis and statistics, but described in much more colloquial terms. Numbers with low precision are termed "garbage" and numbers with high precision are labeled "precise".<br />
<br />
{| class="wikitable"<br />
!Formula<br />
!Explanation<br />
|-<br />
|Precise number + Precise number = Slightly less precise number<br />
|If we know absolute error bars, then adding two precise numbers will at worst add the sizes of the two error bars. For example, if our precise numbers are 1 (±10<sup>-6</sup>) and 1 (±10<sup>-6</sup>), then our sum is 2 (±2·10<sup>-6</sup>). It is possible to lose a lot of relative precision, if the resultant sum is close to zero as a result of adding a number and then close to its inverse. This phenomenon is known as catastrophic cancellation. Therefore, it is likely that all numbers referred here are positive numbers, which does not exhibit this phenomenon.<br />
|-<br />
|Precise number × Precise number = Slightly less precise number<br />
|Here, instead of absolute error, relative error will be added. For example, if our precise numbers are 1 (±10<sup>-6</sup>) and 1 (±10<sup>-6</sup>), then our product is 1 (±2·10<sup>-6</sup>).<br />
|-<br />
|Precise number + Garbage = Garbage<br />
|If one of the numbers has a high absolute error, and the numbers being added are of comparable size, then this error will be propagated to the sum. <br />
|-<br />
|Precise number × Garbage = Garbage<br />
|Likewise, if one of the numbers has a high relative error, then this error will be propagated to the product. Here, this is independent of the sizes of the numbers.<br />
|-<br />
|<math>\sqrt{\text{Garbage}} = \text{Less bad garbage}</math><br />
| When the square root of a number is computed, its relative error will be halved. Depending on the application, this might not be all that much ''better'', but it's at least ''less bad''.<br />
|-<br />
|Garbage<sup>2</sup> = Worse garbage<br />
|Likewise, when a number is squared, its relative error will be doubled. This is a corollary to multiplication adding relative errors.<br />
|-<br />
|<math>\frac{1}{N}\sum(\text{N pieces of statistically independent garbage}) = \text{Better garbage}</math><br />
|By aggregating many pieces of statistically independent observations (for instance, surveying many individuals), it is possible to reduce relative error. This is the basis of statistical sampling.<br />
|-<br />
|Precise number<sup>Garbage</sup> = Much worse garbage<br />
|The exponent is very sensitive to changes, which may also magnify the effect based on the magnitude of the precise number.<br />
|-<br />
|Garbage – Garbage = Much worse garbage<br />
|This line involves catastrophic cancellation. If both pieces of garbage are about the same (e.g. if their error bars overlap), then it is possible that the answer is positive, zero, or negative.<br />
|-<br />
|<math>\frac{\text{Precise number}}{\text{Garbage}-\text{Garbage}}</math> = Much worse garbage, possible division by zero<br />
|Indeed, as with above, if error bars overlap then we might end up dividing by zero.<br />
|-<br />
|Garbage × 0 = Precise number<br />
|Multiplying anything by 0 results in 0, an extremely precise number in the sense that it has no error whatsoever since we supply the 0 ourselves. This is equivalent to discarding garbage data from a statistical analysis.<br />
|}<br />
<br />
The title text refers to the computer science maxim of "garbage in, garbage out," which states that when it comes to computer code, supplying incorrect initial data will produce incorrect results, even if the code itself accurately does what it is supposed to do. As we can see above, however, when plugging data into mathematical formulas, this can possibly magnify the error of our input data, though there are ways to reduce this error (such as aggregating data). Therefore, the quantity of garbage is not necessarily conserved.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
[A series of mathematical equations are written from top to bottom]<br />
<br />
Precise number + Precise number = Slightly less precise number<br />
<br />
Precise number × Precise number = Slightly less precise number<br />
<br />
Precise number + Garbage = Garbage<br />
<br />
Precise number × Garbage = Garbage<br />
<br />
√<span style="border-top:1px solid; padding:0 0.1em;">Garbage</span> = Less bad garbage<br />
<br />
1/N Σ (N pieces of statistically independent garbage) = Better garbage<br />
<br />
(Precise number)<sup>Garbage</sup> = Much worse garbage<br />
<br />
Garbage – Garbage = Much worse garbage<br />
<br />
Precise number / ( Garbage – Garbage ) = Much worse garbage, possible division by zero<br />
<br />
Garbage × 0 = Precise number<br />
<br />
{{comic discussion}}<br />
[[Category:Math]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2270:_Picking_Bad_Stocks&diff=1875182270: Picking Bad Stocks2020-02-19T23:02:06Z<p>162.158.63.154: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 2270<br />
| date = February 19, 2020<br />
| title = Picking Bad Stocks<br />
| image = picking_bad_stocks.png<br />
| titletext = On the news a few days later: "Buzz is building around the so-called 'camping Roomba' after a big investment. Preorders have spiked, and..."<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a CAMPING ROOMBA. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}<br />
<br />
Cueball and Ponytail are discussing the stock market. Ponytail explains that there has been no reliable way to consistently pick stocks that outperform the market average. She also states that there could be a corollary to that; there is no way to consistently pick bad stocks (presumably for this discussion, ''bad stocks'' refers to stocks whose value is expected to go down). Cueball states that he could consistently pick bad stocks, and the last panel shows him at a trading terminal purportedly buying bad stocks, while White Hat and Meghan use his bad stock picks as indications that those stocks should be removed from whatever stock index they manage.<br />
<br />
Generally, people invest in the stock market hoping to make money. They buy stock in companies whose value they expect will increase, and sell stock when they feel its value is about to stop increasing or start decreasing. Someone who could tell whether a stock's price will rise or fall in a given time interval could make a lot of money, but this is an infamously difficult problem. Some investors use {{w|fundamental analysis}}, that is, they attempt to understand companies based on their financial statements and market position to identify which stocks are likely to become more or less valuable over time, while others use {{w|technical analysis}} which seeks to identify patterns in the stock prices themselves. However, while the rise and fall of stock prices are sometimes connected to real events (strong or weak profit statements, new product announcements, major scandals), they often exhibit random-walk behavior, and many studies have shown that an index of randomly-selected stocks (often colloquially stated as "picked by a monkey") beats not only the market's performance as a whole, but also portfolios chosen by experts.<br />
<br />
Realistically, in investing, someone who purposely trades in ''bad stocks'' is called a '''short seller''', and someone who could consistently pick ''bad stock'' could make a lot of money in the stock market. Short selling consists of selling a stock before you own it, with the anticipation that the stock's price will drop soon, and you can later purchase the stock to fulfill the sale. The difference between the selling price and the purchase price is your profit, just as with any normal ("long") purchase and sale. However, in US stock markets, it is illegal to sell stocks that you don't own, so when you short a stock, you need to borrow that stock from a third party (possibly the trading firm you're working with, or some other firm that the trading firm has a stock loan relationship with, that currently holds a position in the stock you're shorting) to cover the sale. This is all done automatically by the trading platform you use. Between the time you sell the stock until the time you repurchase the stock on the open market, you will have what's called a '''short position''' on the stock, and you need to pay interest to the company that lent you that stock. Because of the interest payments, short sales are almost always short-term positions, as the interest paid on the loan can quickly exceed any profit you might make on the sale. {{w|Gary Shilling|A. Gary Shilling}}, a financial analyst, famously remarked that "[https://quoteinvestigator.com/2011/08/09/remain-solvent/ markets can remain irrational a lot longer than you and I can remain solvent.]"<br />
<br />
Cueball's statement about wanting revenge on a ghost may be a reference to [[2259: Networking Problems]], in which Cueball was driven insane trying to debug network problems and came to believe in ghosts. Perhaps the CEO of company #208 has had a similar experience with a network.<br />
<br />
If Cueball's statement that a company is developing a "camping {{w|Roomba}}" is correctly attributing the trademark (as opposed to genericizing it to refer to any small cleaning robot), then presumably company #1434 is {{w|iRobot}}. While a Roomba for camping may sound like a ridiculous concept that is not likely to make much money, developing a robot that can navigate and move around natural environments would be a major advancement leading to new opportunities for both their civilian and military product lines. A campground offers a more challenging environment than indoors, while being slightly more controlled than a truly wild area, making for a good development step. Dropping iRobot from this company's index is probably not a move that would be suggested by a stock broker who is earnestly trying to make money, but maybe Cueball's "market anti-sense" knows something that we don't.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
[Cueball and Ponytail are walking together.]<br />
:Cueball: I feel like by now I should know about the stock market.<br />
:Cueball: What ''is'' investing? Do you just open a website and pick the companies you like?<br />
<br />
[Ponytail holds out her hand palm-up.]<br />
:Ponytail: Well, you totally can.<br />
:Ponytail: But there's a lot of evidence that no investing strategy consistently picks stocks that outperform the average of the whole market. A lot of fund management is a myth.<br />
<br />
[Close-up on Ponytail, who has turned to Cueball.]<br />
:Cueball: Huh, okay.<br />
:Ponytail: But there's a weird corollary to that idea: it implies that, ignoring fees and stuff, it's just as hard to consistently ''lose'' money by picking ''bad'' stocks from an index.<br />
<br />
[Cueball and Ponytail are both back in frame. They are standing still and facing each other.]<br />
:Ponytail: If someone could consistently buy bad stocks, you could beat the average by hiring them, letting them pretend to invest, then buying every stock ''except'' the ones they pick.<br />
:Ponytail: In a way, bad judgement is just as helpful as good judgement.<br />
<br />
[Cueball pumps his fists with excitement.]<br />
:Cueball: Oh my God.<br />
:Cueball: I can do that!<br />
:Ponytail: No, it's just an example--<br />
:Cueball: This is the job I was born for.<br />
<br />
[Cueball is either sitting in a box or being viewed on a camera screen. He is sitting in front of a computer console, and a camera is pointed at him. Megan and White Hat are viewing him, and White Hat is holding a tablet.]<br />
:[Text box: Soon...]<br />
:Cueball: Hey, this company's CEO wants revenge on the same ghost as me! I'm buying!<br />
:Cueball: Ooh, and this one is planning to develop a "Camping Roomba." That's a sure bet!<br />
:Megan: Drop companies #208 and #1434 from the index.<br />
:White Hat: Done.<br />
<br />
{{comic discussion}}</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2270:_Picking_Bad_Stocks&diff=1875172270: Picking Bad Stocks2020-02-19T23:00:12Z<p>162.158.63.154: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 2270<br />
| date = February 19, 2020<br />
| title = Picking Bad Stocks<br />
| image = picking_bad_stocks.png<br />
| titletext = On the news a few days later: "Buzz is building around the so-called 'camping Roomba' after a big investment. Preorders have spiked, and..."<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a CAMPING ROOMBA. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}<br />
<br />
Cueball and Ponytail are discussing the stock market. Ponytail explains that there has been no reliable way to consistently pick stocks that outperform the market average. She also states that there could be a corollary to that; there is no way to consistently pick bad stocks (presumably for this discussion, ''bad stocks'' refers to stocks whose value is expected to go down). Cueball states that he could consistently pick bad stocks, and the last panel shows him at a trading terminal purportedly buying bad stocks, while White Hat and Meghan use his bad stock picks as indications that those stocks should be removed from whatever stock index they manage.<br />
<br />
Generally, people invest in the stock market hoping to make money. They buy stock in companies whose value they expect will increase, and sell stock when they feel its value is about to stop increasing or start decreasing. Someone who could tell whether a stock's price will rise or fall in a given time interval could make a lot of money, but this is an infamously difficult problem. Some investors use {{w|fundamental analysis}}, that is, they attempt to understand companies based on their financial statements and market position to identify which stocks are likely to become more or less valuable over time, while others use {{w|technical analysis}} which seeks to identify patterns in the stock prices themselves. However, while the rise and fall of stock prices are sometimes connected to real events (strong or weak profit statements, new product announcements, major scandals), they often exhibit random-walk behavior, and many studies have shown that an index of randomly-selected stocks (often colloquially stated as "picked by a monkey") beats not only the market's performance as a whole, but also portfolios chosen by experts.<br />
<br />
Realistically, in investing, someone who purposely trades in ''bad stocks'' is called a '''short seller''', and someone who could consistently pick ''bad stock'' could make a lot of money in the stock market. Short selling consists of selling a stock before you own it, with the anticipation that the stock's price will drop soon, you can later purchase the stock to fulfill the sale, and the difference between the selling price and the purchase price is your profit. However, in US stock markets, it is illegal to sell stocks that you don't own, so when you short a stock, you need to borrow that stock from a third party (possibly the trading firm you're working with, or some other firm that the trading firm has a stock loan relationship with, that currently holds a position in the stock you're shorting) to cover the sale. This is all done automatically by the trading platform you use. Between the time you sell the stock until the time you repurchase the stock on the open market, you will have what's called a '''short position''' on the stock, and you need to pay interest to the company that lent you that stock. Because of the interest payments, short sales are almost always short-term positions, as the interest paid on the loan can quickly exceed any profit you might make on the sale. {{w|Gary Shilling|A. Gary Shilling}}, a financial analyst, famously remarked that "[https://quoteinvestigator.com/2011/08/09/remain-solvent/ markets can remain irrational a lot longer than you and I can remain solvent.]"<br />
<br />
Cueball's statement about wanting revenge on a ghost may be a reference to [[2259: Networking Problems]], in which Cueball was driven insane trying to debug network problems and came to believe in ghosts. Perhaps the CEO of company #208 has had a similar experience with a network.<br />
<br />
If Cueball's statement that a company is developing a "camping {{w|Roomba}}" is correctly attributing the trademark (as opposed to genericizing it to refer to any small cleaning robot), then presumably company #1434 is {{w|iRobot}}. While a Roomba for camping may sound like a ridiculous concept that is not likely to make much money, developing a robot that can navigate and move around natural environments would be a major advancement leading to new opportunities for both their civilian and military product lines. A campground offers a more challenging environment than indoors, while being slightly more controlled than a truly wild area, making for a good development step. Dropping iRobot from this company's index is probably not a move that would be suggested by a stock broker who is earnestly trying to make money, but maybe Cueball's "market anti-sense" knows something that we don't.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
[Cueball and Ponytail are walking together.]<br />
:Cueball: I feel like by now I should know about the stock market.<br />
:Cueball: What ''is'' investing? Do you just open a website and pick the companies you like?<br />
<br />
[Ponytail holds out her hand palm-up.]<br />
:Ponytail: Well, you totally can.<br />
:Ponytail: But there's a lot of evidence that no investing strategy consistently picks stocks that outperform the average of the whole market. A lot of fund management is a myth.<br />
<br />
[Close-up on Ponytail, who has turned to Cueball.]<br />
:Cueball: Huh, okay.<br />
:Ponytail: But there's a weird corollary to that idea: it implies that, ignoring fees and stuff, it's just as hard to consistently ''lose'' money by picking ''bad'' stocks from an index.<br />
<br />
[Cueball and Ponytail are both back in frame. They are standing still and facing each other.]<br />
:Ponytail: If someone could consistently buy bad stocks, you could beat the average by hiring them, letting them pretend to invest, then buying every stock ''except'' the ones they pick.<br />
:Ponytail: In a way, bad judgement is just as helpful as good judgement.<br />
<br />
[Cueball pumps his fists with excitement.]<br />
:Cueball: Oh my God.<br />
:Cueball: I can do that!<br />
:Ponytail: No, it's just an example--<br />
:Cueball: This is the job I was born for.<br />
<br />
[Cueball is either sitting in a box or being viewed on a camera screen. He is sitting in front of a computer console, and a camera is pointed at him. Megan and White Hat are viewing him, and White Hat is holding a tablet.]<br />
:[Text box: Soon...]<br />
:Cueball: Hey, this company's CEO wants revenge on the same ghost as me! I'm buying!<br />
:Cueball: Ooh, and this one is planning to develop a "Camping Roomba." That's a sure bet!<br />
:Megan: Drop companies #208 and #1434 from the index.<br />
:White Hat: Done.<br />
<br />
{{comic discussion}}</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2270:_Picking_Bad_Stocks&diff=1875162270: Picking Bad Stocks2020-02-19T22:59:03Z<p>162.158.63.154: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 2270<br />
| date = February 19, 2020<br />
| title = Picking Bad Stocks<br />
| image = picking_bad_stocks.png<br />
| titletext = On the news a few days later: "Buzz is building around the so-called 'camping Roomba' after a big investment. Preorders have spiked, and..."<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a CAMPING ROOMBA. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}<br />
<br />
Cueball and Ponytail are discussing the stock market. Ponytail explains that there has been no reliable way to consistently pick stocks that outperform the market average. She also states that there could be a corollary to that; there is no way to consistently pick bad stocks (presumably for this discussion, ''bad stocks'' refers to stocks whose value is expected to go down). Cueball states that he could consistently pick bad stocks, and the last panel shows him at a trading terminal purportedly buying bad stocks, while White Hat and Meghan use his bad stock picks as indications that those stocks should be removed from whatever stock index they manage.<br />
<br />
Generally, people invest in the stock market hoping to make money. They buy stock in companies whose value they expect will increase, and sell stock when they feel its value is about to stop increasing or start decreasing. Someone who could tell whether a stock's price will rise or fall in a given time interval could make a lot of money, but this is an infamously difficult problem. Some investors use {{w|fundamental analysis}}, that is, they attempt to understand companies based on their financial statements and market position to identify which stocks are likely to become more or less valuable over time, while others use {{w|technical analysis}} which seeks to identify patterns in the stock prices themselves. However, while the rise and fall of stock prices are sometimes connected to real events (strong or weak profit statements, new product announcements, major scandals), they often exhibit random-walk behavior, and many studies have shown that an index of randomly-selected stocks (often colloquially stated as "picked by a monkey") beats not only the market's performance as a whole, but also portfolios chosen by experts.<br />
<br />
Realistically, in investing, someone who purposely trades in ''bad stocks'' is called a '''short seller''', and someone who could consistently pick ''bad stock'' could make a lot of money in the stock market. Short selling consists of selling a stock before you own it, with the anticipation that the stock's price will drop soon, you can later purchase the stock to fulfill the sale, and the difference between the selling price and the purchase price is your profit. However, in US stock markets, it is illegal to sell stocks that you don't own, so when you short a stock, you need to borrow that stock from a third party (possibly the trading firm you're working with, or some other firm that the trading firm has a stock loan relationship with, that currently holds a position in the stock you're shorting) to cover the sale. This is all done automatically by the trading platform you use. Between the time you sell the stock until the time you repurchase the stock on the open market, you will have what's called a '''short position''' on the stock, and you need to pay interest (called "margin") to the company that lent you that stock. Because of the interest payments, short sales are almost always short-term positions, as the interest paid on the loan can quickly exceed any profit you might make on the sale. {{w|Gary Shilling|A. Gary Shilling}}, a financial analyst, famously remarked that "[https://quoteinvestigator.com/2011/08/09/remain-solvent/ markets can remain irrational a lot longer than you and I can remain solvent.]"<br />
<br />
Cueball's statement about wanting revenge on a ghost may be a reference to [[2259: Networking Problems]], in which Cueball was driven insane trying to debug network problems and came to believe in ghosts. Perhaps the CEO of company #208 has had a similar experience with a network.<br />
<br />
If Cueball's statement that a company is developing a "camping {{w|Roomba}}" is correctly attributing the trademark (as opposed to genericizing it to refer to any small cleaning robot), then presumably company #1434 is {{w|iRobot}}. While a Roomba for camping may sound like a ridiculous concept that is not likely to make much money, developing a robot that can navigate and move around natural environments would be a major advancement leading to new opportunities for both their civilian and military product lines. A campground offers a more challenging environment than indoors, while being slightly more controlled than a truly wild area, making for a good development step. Dropping iRobot from this company's index is probably not a move that would be suggested by a stock broker who is earnestly trying to make money, but maybe Cueball's "market anti-sense" knows something that we don't.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
[Cueball and Ponytail are walking together.]<br />
:Cueball: I feel like by now I should know about the stock market.<br />
:Cueball: What ''is'' investing? Do you just open a website and pick the companies you like?<br />
<br />
[Ponytail holds out her hand palm-up.]<br />
:Ponytail: Well, you totally can.<br />
:Ponytail: But there's a lot of evidence that no investing strategy consistently picks stocks that outperform the average of the whole market. A lot of fund management is a myth.<br />
<br />
[Close-up on Ponytail, who has turned to Cueball.]<br />
:Cueball: Huh, okay.<br />
:Ponytail: But there's a weird corollary to that idea: it implies that, ignoring fees and stuff, it's just as hard to consistently ''lose'' money by picking ''bad'' stocks from an index.<br />
<br />
[Cueball and Ponytail are both back in frame. They are standing still and facing each other.]<br />
:Ponytail: If someone could consistently buy bad stocks, you could beat the average by hiring them, letting them pretend to invest, then buying every stock ''except'' the ones they pick.<br />
:Ponytail: In a way, bad judgement is just as helpful as good judgement.<br />
<br />
[Cueball pumps his fists with excitement.]<br />
:Cueball: Oh my God.<br />
:Cueball: I can do that!<br />
:Ponytail: No, it's just an example--<br />
:Cueball: This is the job I was born for.<br />
<br />
[Cueball is either sitting in a box or being viewed on a camera screen. He is sitting in front of a computer console, and a camera is pointed at him. Megan and White Hat are viewing him, and White Hat is holding a tablet.]<br />
:[Text box: Soon...]<br />
:Cueball: Hey, this company's CEO wants revenge on the same ghost as me! I'm buying!<br />
:Cueball: Ooh, and this one is planning to develop a "Camping Roomba." That's a sure bet!<br />
:Megan: Drop companies #208 and #1434 from the index.<br />
:White Hat: Done.<br />
<br />
{{comic discussion}}</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=Talk:2061:_Tectonics_Game&diff=164449Talk:2061: Tectonics Game2018-10-19T18:23:54Z<p>162.158.63.154: </p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
<br />
My wife is trying to physically restrain me from immediately starting to write this game...int main ( int arggggg...ow...get off [[User:SteveBaker|SteveBaker]] ([[User talk:SteveBaker|talk]]) 16:52, 19 October 2018 (UTC)<br />
<br />
Wrote my first transcript. Hopefully it isn't terrible, haha. [[User:IYN|IYN]] ([[User talk:IYN|talk]]) 17:13, 19 October 2018 (UTC)<br />
:Not bad, but please do not remove the incomplete tag too soon. Even my smaller changes don't convince me right now that it's complete. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 17:34, 19 October 2018 (UTC)<br />
<br />
Who wants to help me make this? [[User:Blacksilver|Blacksilver]] ([[User talk:Blacksilver|talk]]) 17:24, 19 October 2018 (UTC)<br />
<br />
With a sufficiently large time warp, this actually sounds like it would be pretty fun. [[User:Ahiijny|Ahiijny]] ([[User talk:Ahiijny|talk]]) 18:20, 19 October 2018 (UTC)<br />
<br />
I know very little about stars. Can anyone explain what the type in the title text is? [[Special:Contributions/162.158.63.70|162.158.63.70]] 18:23, 19 October 2018 (UTC)<br />
<br />
It's like playing Desert Bus for the rest of your life... :) [[Special:Contributions/162.158.63.154|162.158.63.154]] 18:23, 19 October 2018 (UTC) Scott</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2059:_Modified_Bayes%27_Theorem&diff=1642572059: Modified Bayes' Theorem2018-10-15T18:58:27Z<p>162.158.63.154: /* Explanation */ spelling</p>
<hr />
<div>{{comic<br />
| number = 2059<br />
| date = October 15, 2018<br />
| title = Modified Bayes' Theorem<br />
| image = modified_bayes_theorem.png<br />
| titletext = Don't forget to add another term for "probability that the Modified Bayes' Theorem is correct."<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}<br />
{{w|Bayes' Theorem}} is an equation in statistics that gives the probability of a given hypothesis accounting not only for a single experiment or observation but also for your existing knowledge about the hypothesis, i.e. its prior probability. Randall's modified form of the equation also purports to account for the probability that you are indeed applying Bayes' Theorem itself correctly by including that as a term in the equation.<br />
<br />
Bayes' theorem is:<br />
<br />
<math>P(H \mid X) = \frac{P(X \mid H) \, P(H)}{P(X)}</math>,<br />
where<br />
*<math>P(H \mid X)</math> is the probability that <math>H</math>, the hypothesis, is true given observation <math>X</math>. This is called the ''posterior probability''.<br />
*<math>P(X \mid H)</math> is the probability that observation <math>X</math> will appear given the truth of hypothesis <math>H</math>. This term is often called the ''likelihood''<br />
*<math>P(H)</math> is the probability that hypothesis <math>H</math> is true before any observations. This is called the ''prior'', or ''belief''.<br />
*<math>P(X)</math> is the probability of the observation X regardless of any hypothesis might have produced it. This term is called the ''marginal likelihood''.<br />
<br />
The purpose of Bayesian inference is to discover something we want to know (how likely is it that our explanation is correct given the evidence we've seen) by mathematically expressing it in terms of things we can find out: how likely are our observations, how likely is our hypothesis ''a priori'', and how likely are we to see the observations we've seen assuming our hypothesis is true. A Bayesian learning system will iterate over available observations, each time using the likelihood of new observations to update its priors (beliefs) with the hope that, after seeing enough data points, the prior and posterior will converge to a single model.<br />
<br />
If <math>P(C)=1</math> the modified theorem reverts to the original Bayes' theorem (which makes sense, as a probability one would mean certainty that you are using Bayes' theorem correctly).<br />
<br />
If <math>P(C)=0</math> the modified theorem becomes <math>P(H \mid X) = P(H)</math>, which says that the belief in your hypothesis is not affected by the result of the observation (which makes sense because you're certain you're misapplying the theorem so the outcome of the calculation shouldn't affect your belief.)<br />
<br />
This happens because, if you apply the original theorem, the modified theorem can be rewritten as: <math>P(H \mid X) = P(H)(1-P(C)) + P(H \mid X)P(C)</math>. This is the [https://en.wikipedia.org/wiki/Linear_interpolation linear-interpolated] weighted average of the belief you had before the calculation and the belief you would have if you applied the theorem correctly. This goes smoothly from the not believing your calculation at all, keeping the same belief as before if <math>P(C)=0</math> to changing your belief exactly as Bayes' theorem suggests when <math>P(C)=1</math>. <br />
<br />
<math>1-P(C)</math> is the probability that you are using the theorem incorrectly.<br />
<br />
As an equation, the rewritten form makes no sense. <math>P(H \mid X) = P(H)(1-P(C)) + P(H \mid X)P(C)</math> is strangely self-referential and reduces to the piecewise equation <math>\begin{cases}P(H \mid X) = P(H) & P(C) \neq 1 \\ 0 = 0 & P(C) = 1 \end{cases}</math>. However, the Modified Bayes Theorem includes an extra variable not listed in the conditioning, so a person with an AI background might understand that Randal was trying to write an expression for updating <math>P(H \mid X)</math> with knowledge of <math>C</math> i.e. <math>P(H \mid X,C)</math>, the belief in the hypothesis given the observation <math>X</math> and the confidence that you were applying Bayes' theorem correctly <math>C</math>, for which the expression <math>P(H \mid X,C) = P(H)(1-P(C)) + P(H \mid X)P(C)</math> makes some intuitive sense.<br />
<br />
The title text suggests that an additional term should be added for the probability that the Modified Bayes Theorem is correct. But that's *this* equation, so it would make the formula self-referential. It could also result in an infinite regress -- we'd need another term for the probability that the version with the probability added is correct, and another term for that version, and so on. It's also unclear what the point of using an equation we're not sure of is (although sometimes we can: {{w|Newton's Laws}} are not as correct as the Einstein's {{w|Theory of Relativity}} but they're a reasonable approximation in most circumstances}.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:Modified Bayes' theorem:<br />
<br />
:P(H|X) = P(H) × (1 + P(C) × ( P(X|H)/P(X) - 1 ))<br />
<br />
:H: Hypothesis<br />
:X: Observation<br />
:P(H): Prior probability that H is true<br />
:P(X): Prior probability of observing X<br />
:P(C): Probability that you're using Bayesian statistics correctly<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Statistics]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2059:_Modified_Bayes%27_Theorem&diff=1642562059: Modified Bayes' Theorem2018-10-15T18:57:16Z<p>162.158.63.154: added some bayesian terminology and explained inference.</p>
<hr />
<div>{{comic<br />
| number = 2059<br />
| date = October 15, 2018<br />
| title = Modified Bayes' Theorem<br />
| image = modified_bayes_theorem.png<br />
| titletext = Don't forget to add another term for "probability that the Modified Bayes' Theorem is correct."<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}<br />
{{w|Bayes' Theorem}} is an equation in statistics that gives the probability of a given hypothesis accounting not only for a single experiment or observation but also for your existing knowledge about the hypothesis, i.e. its prior probability. Randall's modified form of the equation also purports to account for the probability that you are indeed applying Bayes' Theorem itself correctly by including that as a term in the equation.<br />
<br />
Bayes' theorem is:<br />
<br />
<math>P(H \mid X) = \frac{P(X \mid H) \, P(H)}{P(X)}</math>,<br />
where<br />
*<math>P(H \mid X)</math> is the probability that <math>H</math>, the hypothesis, is true given observation <math>X</math>. This is called the ''posterior probability''.<br />
*<math>P(X \mid H)</math> is the probability that observation <math>X</math> will appear given the truth of hypothesis <math>H</math>. This term is often called the ''likelihood''<br />
*<math>P(H)</math> is the probability that hypothesis <math>H</math> is true before any observations. This is called the ''prior''<br />
*<math>P(X)</math> is the probability of the observation X regardless of any hypothesis might have produced it. This term is called the ''marginal likelihood''.<br />
<br />
The purpose of Baysian inference is to discover something we want to know (how likely is it that our explanation is correct given the evidence we've seen) by mathematically expressing it in terms of things we can find out: how likely are our observations, how likely is our hypothesis ''a priori'', and how likely are we to see the observations we've seen assuming our hypothesis is true. A bayesian learning system will iterate over available observations, each time using the likelihood of new observations to update its priors (beliefs) with the hope that, after seeing enough data points, the prior and posterior will converge to a single model.<br />
<br />
If <math>P(C)=1</math> the modified theorem reverts to the original Bayes' theorem (which makes sense, as a probability one would mean certainty that you are using Bayes' theorem correctly).<br />
<br />
If <math>P(C)=0</math> the modified theorem becomes <math>P(H \mid X) = P(H)</math>, which says that the belief in your hypothesis is not affected by the result of the observation (which makes sense because you're certain you're misapplying the theorem so the outcome of the calculation shouldn't affect your belief.)<br />
<br />
This happens because, if you apply the original theorem, the modified theorem can be rewritten as: <math>P(H \mid X) = P(H)(1-P(C)) + P(H \mid X)P(C)</math>. This is the [https://en.wikipedia.org/wiki/Linear_interpolation linear-interpolated] weighted average of the belief you had before the calculation and the belief you would have if you applied the theorem correctly. This goes smoothly from the not believing your calculation at all, keeping the same belief as before if <math>P(C)=0</math> to changing your belief exactly as Bayes' theorem suggests when <math>P(C)=1</math>. <br />
<br />
<math>1-P(C)</math> is the probability that you are using the theorem incorrectly.<br />
<br />
As an equation, the rewritten form makes no sense. <math>P(H \mid X) = P(H)(1-P(C)) + P(H \mid X)P(C)</math> is strangely self-referential and reduces to the piecewise equation <math>\begin{cases}P(H \mid X) = P(H) & P(C) \neq 1 \\ 0 = 0 & P(C) = 1 \end{cases}</math>. However, the Modified Bayes Theorem includes an extra variable not listed in the conditioning, so a person with an AI background might understand that Randal was trying to write an expression for updating <math>P(H \mid X)</math> with knowledge of <math>C</math> i.e. <math>P(H \mid X,C)</math>, the belief in the hypothesis given the observation <math>X</math> and the confidence that you were applying Bayes' theorem correctly <math>C</math>, for which the expression <math>P(H \mid X,C) = P(H)(1-P(C)) + P(H \mid X)P(C)</math> makes some intuitive sense.<br />
<br />
The title text suggests that an additional term should be added for the probability that the Modified Bayes Theorem is correct. But that's *this* equation, so it would make the formula self-referential. It could also result in an infinite regress -- we'd need another term for the probability that the version with the probability added is correct, and another term for that version, and so on. It's also unclear what the point of using an equation we're not sure of is (although sometimes we can: {{w|Newton's Laws}} are not as correct as the Einstein's {{w|Theory of Relativity}} but they're a reasonable approximation in most circumstances}.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:Modified Bayes' theorem:<br />
<br />
:P(H|X) = P(H) × (1 + P(C) × ( P(X|H)/P(X) - 1 ))<br />
<br />
:H: Hypothesis<br />
:X: Observation<br />
:P(H): Prior probability that H is true<br />
:P(X): Prior probability of observing X<br />
:P(C): Probability that you're using Bayesian statistics correctly<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Statistics]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=1253:_Exoplanet_Names&diff=1625161253: Exoplanet Names2018-09-09T21:30:45Z<p>162.158.63.154: /* Explanation */ "boat" was misspelled as "boast"</p>
<hr />
<div>{{comic<br />
| number = 1253<br />
| date = August 19, 2013<br />
| title = Exoplanet Names<br />
| image = exoplanet names.png<br />
| titletext = If you have any ideas, I hear you can send them to <nowiki>iaupublic@iap.fr</nowiki>.<br />
}}<br />
==Explanation==<br />
On the 14th August 2013, the {{w|International Astronomical Union}} (IAU) [http://www.iau.org/science/news/179/ issued a document] about public naming of astronomical objects. It stated, "IAU fully supports the involvement of the general public, whether directly or through an independent organized vote, in the naming of planetary satellites, newly discovered planets, and their host stars."<br />
<br />
The text above the image states the fact above and then notes that the IAU immediately regret this decision. As we can see from [[Cueball|Cueball's]] question, from [[Ponytail|Ponytail's]] facepalm, and the fact that even [[Megan]] is speechless, the suggestions are appalling. It becomes even worse when [[Hairbun]] tells them that an automatic filter has already been applied to the results, one designed to remove inappropriate entries that don't meet certain criteria. This implies that the list would have been even worse if presented in its unfiltered form (as seen below in the table).<br />
<br />
The naming document also contained, amongst other things, guidelines that suggested names should meet. These include stipulations such as "16 characters or less", "preferably one word", being "pronounceable (in as many languages as possible)", "not too similar to an existing name of an astronomical object", avoiding commercial names, and being "respectful of intellectual property". If we go down the list, we can see that many of [[Randall|Randall's]] suggestions do indeed violate the guidelines. Which is part of the joke as it reflects the tendency of internet submissions to ignore such softly suggested guidelines.<br />
<br />
The randomness and inappropriateness of the suggested names reflects the commonly expected response from anonymous submitters on the internet. Many forums and contests that call for online response and do not apply strict control over the responses receive similar collections of random, inappropriate and obscure submissions that are often only tangentially related to the original subject. For example, Greenpeace held a naming contest for one of the whales recently tagged in their research and preservation campaign and even after selecting the finalists the online voting resulted in naming the whale "Mr. Splashypants". PepsiCo had even less restrictive controls in their marketing campaign that asked the internet to name a new flavour of Mountain Dew. They had to shut down the contest in order to avoid naming the new beverage "Hitler did nothing wrong" which was the current leader at the time and only marginally the most inappropriate of the top ten voted suggestions. Even more recently is the case of {{w|Boaty McBoatface}}, in which the internet decided to dub a British research vessel "Boaty McBoatface". The boat was given the name {{w|RRS Sir David Attenborough}} in the end, with its Autonomous Underwater Vehicle being called "Boaty McBoatface."<br />
<br />
The document also states that naming suggestions may be sent to the email that Randall included in the title text.<br />
<br />
This comic was updated in [[1555: Exoplanet Names 2]].<br />
<br />
{| class="wikitable"<br />
! Star !! Planet !! Suggested Name !! Explanation<br />
|-<br />
| rowspan=7 | {{w|Gliese 667}} || {{w|Gliese 667 Cb|b}} || Space Planet || A very unoriginal name; every planet is in space.<br />
|-<br />
|{{w|Gliese 667 Cc|c}} || PILF || Pun of {{w|MILF pornography|MILF}}, i.e. ''Planet I'd Like to Fuck''. Planet c is a relatively hot planet, within the habitable zone.<br />
|-<br />
|{{w|Gliese 667 Cd|d}} || A Star || "A {{w|Star}}" is obviously a bad name for a planet. A* (pronounced "A star") is already used in in astronomy, for example the Milky Way's black hole core is {{w|Sagittarius A*}}. "A star" is also the name for the character {{w|asterisk}} and the name of the popular {{w|A* search algorithm}} in computer science.<br />
|-<br />
|{{w|Gliese 667 Ce|e}} || e'); DROP TABLE PLANETS;-- || A reference to {{w|SQL injection}}, riffing off of [[327|comic 327]], which featured a schoolboy named <code>[[Robert'); DROP TABLE students;--]]</code>. The idea here is that the IAU would enter the name into their system and promptly lose all of their data pertaining to planets. Note that Planet e is located in the habitable zone of the star system.<br />
|-<br />
|{{w|Gliese 667 Cf|f}} || Blogosphere || rowspan = 2 | Weird ''{{w|blog}}''-related terms are a recurring theme in xkcd. See, for instance, [[181|comic 181]].<br />
|-<br />
|{{w|Gliese 667 Cg|g}} || Blogodrome<br />
|-<br />
|[http://exoplanet.eu/catalog/gj_667c_h/ h] || Earth || Planet candidate h is about the mass of the Earth, and described as "tantalizing": [http://www.aanda.org/articles/aa/abs/2013/08/aa21331-13/aa21331-13.html A dynamically-packed planetary system around GJ with three super-Earths in its habitable zone]. See also ([[1231: Habitable Zone]]).<br />
|-<br />
| rowspan=5 | {{w|Tau Ceti}} || [http://exoplanet.eu/catalog/tau_cet_b/ b] || Sid Meier's Tau&nbsp;Ceti&nbsp;B || This refers to the game {{w|Sid Meier's Alpha Centauri}}.<br />
|-<br />
| [http://exoplanet.eu/catalog/tau_cet_c/ c] || Giant Dog Planet || {{w|VY Canis Majoris}} is one of the largest known stars at our galaxy and belongs to the constellation {{w|Canis Major}}, Latin for "greater dog". The constellation further contains {{w|Sirius}}, the brightest star in the night sky, also called "Dog Star".<br />
|-<br />
|[http://exoplanet.eu/catalog/tau_cet_d/ d] || Tiny Dog Planet || cf. {{w|Canis Minor}}, Latin for "lesser dog", another constellation.<br />
|-<br />
|{{w|Tau Ceti e|e}} || Phil Plainet || A reference to {{w|Phil Plait}}, a.k.a. The Bad Astronomer.<br />
|-<br />
|{{w|Tau Ceti f|f}} || Unicode Snowman || The Unicode character <span style="font-size: 200%">☃</span> may be a reference to the planet's estimated surface temperature of -40&nbsp;°C (-40&nbsp;°F). However, this name would be pronounced differently (being a symbol, not a word or name) in different languages. Planets in our solar system are assigned to {{w|Astronomical symbols|astronomical symbols}} like <span style="font-size:150%">&#x2641;</span> for Earth or <span style="font-size:150%">&#x2642;</span> for Mars. (A unicode snowman is also referenced in Randall's book ''What If'', where it is keymapped to a laptop.)<br />
|-<br />
| {{w|Gliese 832}} || {{w|Gliese 832 b|b}} || Asshole Jupiter || This massive planet orbits a {{w|red dwarf}} star at the longest known period of 3416 days at this category.<br />
|-<br />
| rowspan=6 | {{w|Gliese 581}} || {{w|Gliese 581 b|b}} || Waist-deep Cats || {{w|Waist Deep}} is an action film from 2006, and the {{w|Lolcat}} meme does not need explaining. The name may also simply be a reference to being "waist-deep" in (i.e. surrounded by many) cats.<br />
|-<br />
| {{w|Gliese|c}} || Planet #14 || About 200th discovered exoplanet (in 2007); reported to be the first potentially Earth-like planet in the habitable zone of its star, though that is in doubt now. The joke might be that like "Space Planet", "Planet #14" is a generic and unoriginal name. Also note that this is the 15th entry in the table so the numbering is {{w|Zero-based_numbering|zero-based}}.<br />
An interesting (?) coincidence is that the 14th and 15th {{w|Definition of planet#Minor planets|Minor planets}} (then called asteroids) were discovered in 1851; see see {{w|List of minor planets: 1–1000}}. If they were to be counted among the planets of the {{w|Solar System}}, as was sometimes done then, the 14th known planetary body would be {{w| 7 Iris|Iris}} (discovered in 1847, a year before {{w|Neptune}}).<br />
|-<br />
|{{w|Gliese 581 d|d}} || Ballderaan || A {{w|wikt:balls|crude pun}} on the planet {{w|Alderaan}} from the ''{{w|Star Wars}}'' universe.<br />
|-<br />
|{{w|Gliese 581 e|e}} || Eternia Prime || {{w|Eternia}} is a fictional planet, venue of the ''{{w|Masters of the Universe}}'' animated series and toy collection.<br />
|-<br />
| {{w|Gliese 581 f|f}} || Taupe Mars || {{w|Kim Stanley Robinson}}'s award-winning {{w|Mars trilogy}} (''Red Mars, Green Mars, Blue Mars'' after various stages of {{w|terraformation}}). {{w|Taupe}} is a brownish-grey colour.<br />
|-<br />
|{{w|Gliese|g}} || Jelly-Filled Planet || Possibly a reference to the conjecture that this tidally locked planet has an isolated habitable zone under the substellar point, akin to the pocket of jelly in a jelly doughnut.<br />
|-<br />
| rowspan=2 | {{w|Epsilon Eridani}} || {{w|Epsilon Eridani b|b}} || Skydot || [http://skydot.lanl.gov SkyDOT] is the Sky Database for Objects in Time-Domain run by {{w|LANL}} for the {{w|U.S. Dept. of Energy}} and includes data for [http://skydot.lanl.gov/nsvs/star.php?num=14831575&mask=32004 Epsilon Eridani] that can be used to constrain the orbital parameters of &epsilon; Eri b. It may also refer to how objects in space may appear as bland, bright dots in the night sky.<br />
|-<br />
| {{w|Epsilon Eridani c#Planet_c|c}} || Laser Noises || A {{w|Laser}} does not produce {{w|Noise (electronics)|noise}} in the signal sense; it only works at a well defined frequency. In science fiction films, however, laser weapon discharges are usually accompanied by sound ("pew pew" or the like). Sun-like Epsilon Eridani became a popular setting for science fiction after its publicity as a target of the {{w|Project Ozma}} experiment.<br />
|-<br />
| rowspan=2 | {{w|Gliese 176}} || {{w|Gliese 176 b|b}} || Pandora || The mythological name {{w|Pandora}} fulfills most of IAU's guidelines and has been popular for planets in science fiction; most recently and famously is {{w|Pandora (Avatar)|the venue}} of James Cameron's ''{{w|Avatar (film)|Avatar}}'' (although actually it is not a planet but just a moon of a gas giant in Alfa Centauri A). It is also a hellish planet from {{w|Frank Herbert}}'s {{w|Frank Herbert bibliography#WorShip novels|WorShip}} series of novels, a jungle planet in Brothers Strugatsky's {{w|Noon Universe}} and the planet used in {{w|Borderlands (video game)|Borderlands Games}}.<br />
|-<br />
| [http://exoplanet.eu/catalog/gj_176_c/ c] || Pantera || Named for the {{w|Pantera|heavy metal band}}, which itself was named after an Italian sports car, the {{w|De Tomaso Pantera}}.<br />
|-<br />
| Kepler-61 || {{w|Kepler-61b|b}} || GoldenPalace.com || A gambling website, known for {{w|GoldenPalace.com|paying to have their name in unusual places}} (like forehead tattoos, species names...).<br />
|-<br />
! colspan=4 | (right column)<br />
|-<br />
| rowspan=3 | {{w|Upsilon Andromedae}} || {{w|Upsilon Andromedae c|c}} || Stampy || The name of the elephant from the {{w|Simpsons}} episode {{w|Bart Gets an Elephant}}.<br />
|-<br />
|{{w|Upsilon Andromedae d|d}} || Moonchild || The name Bastian gives the Childlike Empress in {{w|The Neverending Story}}.<br />
|-<br />
|{{w|Upsilon Andromedae e|e}} || Ham Sphere || [http://www.hamsphere.com HamSphere] is a {{w|Amateur radio|Ham Radio}} simulator program. Ham radio uses designated radio frequencies for non-commercial exchange of messages and more. A pun of Hemisphere.<br />
|-<br />
| rowspan=3 | {{w|. Eridani|HD 20794}} || [http://exoplanet.eu/catalog/hd_20794_b/ b] || Cosmic Sands || style="font-family:'Comic Sans MS', 'Comic Sans'" | A {{w|pun}} on the name of the font {{w|Comic Sans}}. (<span style="font-family:papyrus">See also: [[590|590: Papyrus]].</span>)<br />
|-<br />
| [http://exoplanet.eu/catalog/hd_20794_c/ c] || Legoland || {{w|Legoland}} is a chain of {{w|theme park}}s owned by the {{w|Lego Group}}.<br />
|-<br />
|[http://exoplanet.eu/catalog/hd_20794_d/ d] || Planet with Arms || A reference to the [http://web.archive.org/web/20160119111332/http://www.thecolorsofmysoul.com/wp-content/uploads/2012/12/The-Hitchhikers-Guide-to-the-Galaxy.jpg early covers] of {{w|Hitchhiker's Guide to the Galaxy}}? Could also be a reference to [http://knowyourmeme.com/memes/birds-with-arms "Birds with Arms" meme].<br />
|-<br />
| {{w|HD 85512}} || {{w|HD 85512 b|b}} || Lax Morality || Possibly a parody of science fiction in which certain planets are suggested to be uniformly... lax in morals (i.e. full of sex, drugs, etc.). See http://tvtropes.org/pmwiki/pmwiki.php/Main/Planetville and related.<br />
|-<br />
| rowspan=6 | {{w|HD 40307}} || {{w|HD 40307 b|b}} || Good Planet || Similar to the above, except with good planets. May also be yet another non-descriptive name, like "Space Planet" and "Planet #14".<br />
|-<br />
|{{w|HD|c}} || ProblemLand || See above.<br />
|-<br />
|{{w|HD 40307 d|d}} || Slickle || This is a reference to "[http://zdarsky.tumblr.com/post/2837139960 The Petals Fall Twice]", which was made as a humorous example of bad fan-fiction. The word itself is a portmanteau of "slowly", "licked", and "tickled".<br />
|-<br />
|{{w|HD 40307 e|e}} || Spare Parts || This suggests that the planet is "worthless" or "junk". This is false, of course. May be a reference to the fact it is a planet with nothing much different from the other planets.<br />
|-<br />
|{{w|HD 40307 f|f}} || New Jersey VI || Refers to the state of {{w|New Jersey}}; may be an insult to either.<br />
|-<br />
|{{w|HD|g}} || How Do I Join the&nbsp;IAU || This implies that the user "got lost" on the IAU website and thought that the "planet name suggestion" input was for general queries.<br />
|-<br />
| rowspan=3 | {{w|Gliese 163}} || [http://exoplanet.eu/catalog/gj_163_b/ b] || Neil Tyson's Mustache || {{w|Neil deGrasse Tyson}} is a famous American astrophysicist and science communicator who does maintain a distinguished mustache.<br />
|-<br />
|{{w|Gliese|c}} || help@gmail.com || Similar to "How Do I Join the IAU", this implies that the user confused the "planet suggestion" text box for a new email they are trying to send<br />
|-<br />
|[http://exoplanet.eu/catalog/gj_163_d/ d] || Hair-Covered Planet || Refers to the well-known {{w|Hairy ball theorem}} of topology.<br />
|-<br />
| {{w|Pi Mensae}} || {{w|Pi Mensae b|b}} || Moon Holder || {{w|Jupiter}} has more than 60 discovered moons, and still counting... A planet ten times more massive ''must'' also be a Moon Holder.<br />
|-<br />
| {{w|HD 189733}} || {{w|HD 189733 b|b}} || Permadeath || A well-characterized "{{w|Hot Jupiter}}" at a temperature range of 973 ± 33 K to 1,212 ± 11 K. The name refers to the feature of {{w|Permanent death}} common in many RPGs and roguelikes.<br />
|-<br />
| {{w|Kepler-22}} || {{w|Kepler-22 b|b}} || Blue Ivy || Blue Ivy Carter is the daughter of musicians {{w|Beyoncé}} and {{w|Jay-Z}}.<br />
|-<br />
| Kepler-3284 || b || Blainsley || A very small town in the United Kingdom, south of Edinburgh. Possibly chosen due to its insignificance?<br />
|-<br />
| Kepler-3255 || b || Unicorn Thresher || As far as we can tell, Kepler-3255b is in the vicinity of the constellation Monoceros, aka the Unicorn. Also a pun on {{w|Threshing machine|corn thresher}}.<br />
|-<br />
| Kepler-2418 || b || Spherical Discworld || {{w|The Discworld}} is the fictional setting for British author {{w|Terry Pratchett}}'s {{w|Discworld}} series of humorous fantasy novels; it consists of a large disc supported by four elephants themselves standing on top of a turtle flying through space. "Spherical Disc" would be an oxymoron.<br />
|-<br />
| Kepler-1686 || {{w|KOI-1686.01|b}} || Emergency Backup Earth || This candidate planet has an {{w|Earth Similarity Index}} of 0.89, making it one of the most habitable {{w|Kepler object of interest}}. The name suggests that it could be used as a backup in case something happened to our current planet.<br />
|-<br />
| Kepler-3010 || b || Feeeoooooooop || Possibly the onomatopoeia for something getting sucked into a black hole.<br />
|-<br />
| Kepler-4742 || b || Liz || ...Just a regular name (for a person, not a planet). Maybe a reference to the pet lizard on the Magic School Bus. <br />
|}<br />
<br />
==Transcript==<br />
:[Text above the first frame of the comic:]<br />
::August 2013:<br />
:The International Astronomical Union <br />
:decides to start naming exoplanets,<br />
:and—for the first time ever—asks for <br />
:suggestions from the general public.<br />
:::They immediately regret this decision.<br />
:[Ponytail is facepalming while Megan and Cueball are looking at a computer screen on a desk. Hairbun points to the screen.]<br />
:Cueball: Can't you filter out the worst ones?<br />
:Hairbun: This is '''''after''''' the filter!<br />
<br />
:[Below is a table showing the list of planet names as seen on the computer screen with gray background around the edges of the table.]<br />
<br />
:[The table is in two separate columns, but there is only headings over the left, so the right column is a direct continuation of the left. In the table it is mentioned when the right column begins. There is a small arrow pointing from the word "Planet" down to the second column of the table. The headings in the comic are not inside the table as they are here below. The text at the bottom of the left list seems to continue on below, at least the last entry is cut below the middle, although it is still easy to read. Similarly the text at the top right list, seems to continue from above, the top entry missing the very top of the text. This is as if the list is much longer and here is just shown part of the list. To further indicate this the first entry in the right list begins at "c" instead of at "b" which is else the case for all other instances.]<br />
<br />
:{| class="wikitable"<br />
! Star !! Planet !! Suggested Name<br />
|-<br />
| rowspan=7 |Gliese 667||b||Space Planet<br />
|-<br />
|c||PILF<br />
|-<br />
|d||A Star<br />
|-<br />
|e||e'); DROP TABLE PLANETS;--<br />
|-<br />
|f||Blogosphere<br />
|-<br />
|g||Blogodrome<br />
|-<br />
|h||Earth<br />
|-<br />
| rowspan=5 |Tau Ceti||b||Sid Meier's Tau Ceti B<br />
|-<br />
|c||Giant Dog Planet<br />
|-<br />
|d||Tiny Dog Planet<br />
|-<br />
|e||Phil Plainet<br />
|-<br />
|f||Unicode Snowman<br />
|-<br />
|Gliese 832||b||Asshole Jupiter<br />
|-<br />
| rowspan= 6|Gliese 581||b||Waist-deep Cats<br />
|-<br />
|c||Planet #14<br />
|-<br />
|d||Ballderaan<br />
|-<br />
|e||Eternia Prime<br />
|-<br />
|f||Taupe Mars<br />
|-<br />
|g||Jelly-Filled Planet<br />
|-<br />
| rowspan= 2|Epsilon Eridani||b||Skydot<br />
|-<br />
|c||Laser Noises<br />
|-<br />
| rowspan= 2|Gliese 176||b||Pandora<br />
|-<br />
|c||Pantera<br />
|-<br />
|Kepler-61||b||GoldenPalace.com<br />
|-<br />
! colspan=3 | [Below is the right column.]<br />
|-<br />
| rowspan= 3|Upsilon Andromidae||c||Stampy<br />
|-<br />
|d||Moonchild<br />
|-<br />
|e||Ham Sphere<br />
|-<br />
| rowspan= 3|HD 20794||b||Cosmic Sands<br />
|-<br />
|c||Legoland<br />
|-<br />
|d||Planet with Arms<br />
|-<br />
|HD 85512||b||Lax Morality<br />
|-<br />
| rowspan= 6|HD 40307||b||Good Planet<br />
|-<br />
|c||Problemland<br />
|-<br />
|d||Slickle<br />
|-<br />
|e||Spare Parts<br />
|-<br />
|f||New Jersey VI<br />
|-<br />
|g||How Do I Join the IAU<br />
|-<br />
| rowspan= 3|Gliese 163||b||Neil Tyson's Mustache<br />
|-<br />
|c||help@gmail.com<br />
|-<br />
|d||Hair-Covered Planet<br />
|-<br />
|Pi Mensae||b||Moon Holder<br />
|-<br />
|HD 189733||b||Permadeath<br />
|-<br />
|Kepler-22||b||Blue Ivy<br />
|-<br />
|Kepler-3284||b||Blainsley<br />
|-<br />
|Kepler-3255||b||Unicorn Thresher<br />
|-<br />
|Kepler-2418||b||Spherical Discworld<br />
|-<br />
|Kepler-1686||b||Emergency Backup Earth<br />
|-<br />
|Kepler-3010||b||Feeeoooooooop<br />
|-<br />
|Kepler-442||b||Liz<br />
|}<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Exoplanet Names]]<br />
[[Category:Comics sharing name|Exoplanet Names]]<br />
[[Category:Charts]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Comics featuring Ponytail]]<br />
[[Category:Comics featuring Hairbun]]<br />
[[Category:Comics featuring Little Bobby Tables]]<br />
[[Category:Astronomy]]<br />
[[Category:Sex]]<br />
[[Category:Exoplanets]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2035:_Dark_Matter_Candidates&diff=1615742035: Dark Matter Candidates2018-08-20T15:38:32Z<p>162.158.63.154: I forgot a word</p>
<hr />
<div>{{comic<br />
| number = 2035<br />
| date = August 20, 2018<br />
| title = Dark Matter Candidates<br />
| image = dark_matter_candidates.png<br />
| titletext = My theory is that dark matter is actually just a thin patina of grime covering the whole universe, and we don't notice it because we haven't thoroughly cleaned the place in eons.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Every section needs to be filled and explained. Do NOT delete this tag too soon.}}<br />
{{w|Dark matter}} is a hypothetical form of matter used by the vast majority of astronomers to explain the far too high apparent mass of objects at large scales in our universe. In galaxies, stars are orbiting faster than the gravitational force of the sum of the masses of visible matter in the galaxy could cause, and entire galaxies are observed moving much faster around each other than their visible masses could explain. In galactic collisions, the mass can appear to separate from the visible matter, as if the mass doesn't collide but the visible matter does. A small handful galaxies have been observed to not have this property, suggesting that it is a *thing* that a galaxy can have more or less of and is separable from. At scales of our solar system those effects are too small and can't be measured. In cosmology, dark matter is estimated to account for 85% of the total matter in the universe.<br />
<br />
This comic gives a set of possibilities of what dark matter could possibly be, charted by mass from smallest (given in {{w|Electronvolt#Mass|electronvolts}}) to largest (given in kilograms). Masses in the range 10<sup>-15</sup> kg to 10<sup>-3</sup> kg are given in grammes. <br />
<br />
The joke in this comic is that the range of the mass of the possible particles and objects stretch over 81 powers of ten. [[Randall]] filled the gap between real small candidate particles and real large candidate objects with highly absurd suggestions.<br />
<br />
;Axion<br />
An {{w|Axion|Axion}} is a hypothetical elementary particle that might be a component of dark matter.<br />
<br />
;Sterile neutrino<br />
{{w|Sterile neutrino|Sterile neutrinos}} are hypothetical particles interacting only via gravity. It's an actual candidate for dark matter.<br />
<br />
;Electrons painted with space camouflage<br />
Electrons are fundamental particles which compose the outer layers of atoms. A large number of electrons in the galaxy would be relatively easy to detect, as they not only interact with light (which dark matter does not appear to), but have a strong electric charge. Presumably, space camouflage is a positively-charged coating which prevents electrons from interacting with light. (Needless to say, this is not an actual candidate for dark matter.)<br />
<br />
;Neutralino<br />
A {{w|Neutralino|Neutralino}} is a hypothetical particle from {{w|Supersymmetry|Supersymmetry}}, not something made up by Randall Munroe that sounds vaguely like one. It's an actual candidate for dark matter.<br />
<br />
;Q-ball<br />
In theoretical physics, a {{w|Q-ball|Q-ball}} is a stable group of particles. It's an actual candidate for dark matter.<br />
<br />
In billiards, a cue ball is the white (or yellow) ball hit with the cue in normal play.<br />
<br />
;Pollen<br />
{{w|Pollen|Pollen}} is a joke candidate, though people with seasonal allergies may suspect that the universe genuinely is made up entirely of pollen in the springtime. <br />
<br />
;No-See-Ums<br />
{{w|Ceratopogonidae|No-See-Ums}}, also called Ceratopogonidae, a family of small flies (1–4 mm long) who can pass through most window screens. Another joke candidate.<br />
<br />
;8-balls<br />
In pool, the {{w|Pool (cue sports)|8-ball}} is a black ball numbered 8. It's a pun with Q-ball/cue ball. Unless undetected aliens have discovered billiards and become addicted to it, 8-balls are found only on Earth and are, hence, unlikely dark matter candidates.<br />
<br />
;Space Cows<br />
Cows are Bovines extensively farmed on Earth for milk and meat. Although there is folk lore concerning cows {{w|Hey diddle diddle|acheiving circum-lunar orbits}}, they have yet to be found elsewhere in the Universe.<br />
<br />
;Obelisks, Monoliths, Pyramids<br />
While those human constructions are huge on a human scale, they're negligible at universe-scale. It would take a large number of such constructions, distributed through space, to replicate the effects of dark matter; while a scenario could be envisioned where enough such constructs existed, with properties and distribution allowing them to match observations, this is obviously not a likely explanation.<br />
They often show up in fiction and pseudo-scientific literature as alien artifacts generating immense unknown power out of nowhere, with the most famous and influential example being the monolith from 2001: A Space Odyssey.<br />
<br />
;Black Holes ruled out by:<br />
{{w|Black hole|Black holes}} are known in sizes of a few sun masses (about 10<sup>30</sup>-10<sup>31</sup> kg) as remnants of the core of former big stars and the real big ones at the centers of galaxies (millions or even billions of the mass of the sun.) But recent gravitational wave detection indicate that black holes at 50 or 100 sun masses also exist while their origin is still not understood. Randall doesn't mention this but some astronomers hope that these could fill at least a part of the gap.<br />
<br />
Except the last item all range below the mass of the sun (2x10<sup>30</sup> kg) while the smallest known black hole is about four sun masses.<br />
* Gamma rays: If dark matter were black holes of this size, the black holes would be evaporating in bursts of hawking radiation, and we'd see a buzz of gamma rays from every direction.<br />
* GRB lensing: {{w|Gamma-ray burst|gamma-ray bursts}} (GRBs) are the brightest events in the universe only been observed in distant galaxies. While gravitational microlensing (see below) is an astronomical phenomenon it doesn't make much sense here. GRBs are short (milliseconds to several hours) and often only detected by gamma-ray satellites in space but rarely at any other wavelengths. Measuring lensing effects would be very difficult.<br />
* Neutron star data<br />
* Micro lensing<br />
* Solar system stability<br />
* Buzzkill Astronomers: Black holes above a certain size would be impossible to miss, due to the effects they have on nearby matter.<br />
<br />
;Maybe those orbit lines on space diagrams are real and very heavy<br />
Any diagram of our solar system (or any solar system) will show lines representing the path the planet takes around its sun. Since planets orbit in ellipses, there will be an ellipse for every planet. This lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be ''huge'' (Earth's would be 940 million km long (2π AU) and Neptune's would be 28 ''billion'' kilometers long. [https://www.youtube.com/watch?v=0fKBhvDjuy0 Powers of Ten (1977)] gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the inner four planets, including the Earth, which would be a problem. Overall, not a very likely candidate.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:Dark matter candidates:<br />
:[A line graph is shown and labeled at left quarter in eV and further to the right in g together with some prefixes.]<br />
:[The labels read:]<br />
:µeV, meV, eV, keV, MeV, GeV, TeV, 10<sup>-18</sup>kg, ng, µg, mg, g, kg, TON, 10<sup>6</sup>kg, 10<sup>12</sup>kg, 10<sup>18</sup>kg, 10<sup>24</sup>kg, 10<sup>30</sup>kg<br />
<br />
:[All items are shown in bars ranging between two approximately values:]<br />
:< 1 µeV - 10 meV: Axion<br />
<br />
:1 eV - 10 keV: Sterile neutrino<br />
<br />
:1 MeV (exactly): Electrons painted with space camouflage<br />
<br />
:10 GeV - 10 TeV: Neutralino<br />
<br />
:100 TeV - 10<sup>-17</sup> kg: Q-ball<br />
<br />
:1 ng - 100 ng: Pollen<br />
<br />
:0.1 mg - 1 mg: No-See-Ums<br />
<br />
:10<sup>-1</sup> g (exactly): Bees<br />
<br />
:10 g - 100 g: 8-balls<br />
<br />
:100 kg - TON: Space cows<br />
<br />
:TON - 10<sup>9</sup> kg: Obelisks, monoliths, pyramids<br />
<br />
:10<sup>9</sup> kg - 10<sup>33</sup> kg: Black holes ruled out by:<br />
::10<sup>9</sup> kg - 10<sup>13</sup> kg: Gamma rays<br />
::10<sup>13</sup> kg - 10<sup>17</sup> kg: GRB lensing<br />
::10<sup>15</sup> kg - 10<sup>22</sup> kg: Neutron star data<br />
::10<sup>21</sup> kg - 10<sup>30</sup> kg: Micro lensing<br />
::10<sup>24</sup> kg - 10<sup>30</sup> kg: Solar system stability<br />
::10<sup>30</sup> kg - 10<sup>33</sup> kg: Buzzkill astronomers<br />
<br />
:10<sup>33</sup> kg - >10<sup>36</sup> kg: Maybe those orbit lines on space diagrams are real and very heavy<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Science]]<br />
[[Category:Physics]]<br />
[[Category:Astronomy]]<br />
[[Category:Line graphs]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2035:_Dark_Matter_Candidates&diff=1615722035: Dark Matter Candidates2018-08-20T15:26:54Z<p>162.158.63.154: /* Explanation */ More bad grammar fixed.</p>
<hr />
<div>{{comic<br />
| number = 2035<br />
| date = August 20, 2018<br />
| title = Dark Matter Candidates<br />
| image = dark_matter_candidates.png<br />
| titletext = My theory is that dark matter is actually just a thin patina of grime covering the whole universe, and we don't notice it because we haven't thoroughly cleaned the place in eons.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Every section needs to be filled and explained. Do NOT delete this tag too soon.}}<br />
{{w|Dark matter}} is a hypothetical form of matter used by the vast majority of astronomers to explain the far too high apparent mass of objects at large scales in our universe. In galaxies, stars are orbiting faster than the gravitational force of the sum of the masses of visible matter in the galaxy could cause, and entire galaxies are observed moving much faster around each other than their visible masses could explain. In galactic collisions, the mass can appear to separate from the visible matter, as if the mass doesn't collide but the visible matter does. A small galaxies have been observed to not have this property, suggesting that it is a *thing* that a galaxy can have more or less of and is separable from. At scales of our solar system those effects are too small and can't be measured. In cosmology, dark matter is estimated to account for 85% of the total matter in the universe.<br />
<br />
This comic gives a set of possibilities of what dark matter could possibly be, charted by mass from smallest (given in {{w|Electronvolt#Mass|electronvolts}}) to largest (given in kilograms). Masses in the range 10<sup>-15</sup> kg to 10<sup>-3</sup> kg are given in grammes. <br />
<br />
The joke in this comic is that the range of the mass of the possible particles and objects stretch over 81 powers of ten. [[Randall]] filled the gap between real small candidate particles and real large candidate objects with highly absurd suggestions.<br />
<br />
;Axion<br />
An {{w|Axion|Axion}} is a hypothetical elementary particle that might be a component of dark matter.<br />
<br />
;Sterile neutrino<br />
{{w|Sterile neutrino|Sterile neutrinos}} are hypothetical particles interacting only via gravity. It's an actual candidate for dark matter.<br />
<br />
;Electrons painted with space camouflage<br />
Electrons are fundamental particles which compose the outer layers of atoms. A large number of electrons in the galaxy would be relatively easy to detect, as they not only interact with light (which dark matter does not appear to), but have a strong electric charge. Presumably, space camouflage is a positively-charged coating which prevents electrons from interacting with light. (Needless to say, this is not an actual candidate for dark matter.)<br />
<br />
;Neutralino<br />
A {{w|Neutralino|Neutralino}} is a hypothetical particle from {{w|Supersymmetry|Supersymmetry}}, not something made up by Randall Munroe that sounds vaguely like one. It's an actual candidate for dark matter.<br />
<br />
;Q-ball<br />
In theoretical physics, a {{w|Q-ball|Q-ball}} is a stable group of particles. It's an actual candidate for dark matter.<br />
<br />
In billiards, a cue ball is the white (or yellow) ball hit with the cue in normal play.<br />
<br />
;Pollen<br />
{{w|Pollen|Pollen}} is a joke candidate, though people with seasonal allergies may suspect that the universe genuinely is made up entirely of pollen in the springtime. <br />
<br />
;No-See-Ums<br />
{{w|Ceratopogonidae|No-See-Ums}}, also called Ceratopogonidae, a family of small flies (1–4 mm long) who can pass through most window screens. Another joke candidate.<br />
<br />
;8-balls<br />
In pool, the {{w|Pool (cue sports)|8-ball}} is a black ball numbered 8. It's a pun with Q-ball/cue ball. Unless undetected aliens have discovered billiards and become addicted to it, 8-balls are found only on Earth and are, hence, unlikely dark matter candidates.<br />
<br />
;Space Cows<br />
Cows are Bovines extensively farmed on Earth for milk and meat. Although there is folk lore concerning cows {{w|Hey diddle diddle|acheiving circum-lunar orbits}}, they have yet to be found elsewhere in the Universe.<br />
<br />
;Obelisks, Monoliths, Pyramids<br />
While those human constructions are huge on a human scale, they're negligible at universe-scale. It would take a large number of such constructions, distributed through space, to replicate the effects of dark matter; while a scenario could be envisioned where enough such constructs existed, with properties and distribution allowing them to match observations, this is obviously not a likely explanation.<br />
They often show up in fiction and pseudo-scientific literature as alien artifacts generating immense unknown power out of nowhere, with the most famous and influential example being the monolith from 2001: A Space Odyssey.<br />
<br />
;Black Holes ruled out by:<br />
{{w|Black hole|Black holes}} are known in sizes of a few sun masses (about 10<sup>30</sup>-10<sup>31</sup> kg) as remnants of the core of former big stars and the real big ones at the centers of galaxies (millions or even billions of the mass of the sun.) But recent gravitational wave detection indicate that black holes at 50 or 100 sun masses also exist while their origin is still not understood. Randall doesn't mention this but some astronomers hope that these could fill at least a part of the gap.<br />
<br />
Except the last item all range below the mass of the sun (2x10<sup>30</sup> kg) while the smallest known black hole is about four sun masses.<br />
* Gamma Rays: If dark matter were black holes of this size, the black holes would be evaporating in bursts of hawking radiation, and we'd see a buzz of gamma rays from every direction.<br />
* GRB lensing<br />
* Neutron Star Data<br />
* Micro lensing<br />
* Solar System Stability<br />
* Buzzkill Astronomers: Black holes above a certain size would be impossible to miss, due to the effects they have on nearby matter.<br />
<br />
;Maybe those orbit lines on space diagrams are real and very heavy<br />
Any diagram of our solar system (or any solar system) will show lines representing the path the planet takes around its sun. Since planets orbit in ellipses, there will be an ellipse for every planet. This lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be ''huge'' (Earth's would be 940 million km long (2π AU) and Neptune's would be 28 ''billion'' kilometers long. [https://www.youtube.com/watch?v=0fKBhvDjuy0 Powers of Ten (1977)] gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the inner four planets, including the Earth, which would be a problem. Overall, not a very likely candidate.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:Dark matter candidates:<br />
:[A line graph is shown and labeled at left quarter in eV and further to the right in g together with some prefixes.]<br />
:[The labels read:]<br />
:µeV, meV, eV, keV, MeV, GeV, TeV, 10<sup>-18</sup>kg, ng, µg, mg, g, kg, TON, 10<sup>6</sup>kg, 10<sup>12</sup>kg, 10<sup>18</sup>kg, 10<sup>24</sup>kg, 10<sup>30</sup>kg<br />
<br />
:[All items are shown in bars ranging between two approximately values:]<br />
:< 1 µeV - 10 meV: Axion<br />
<br />
:1 eV - 10 keV: Sterile neutrino<br />
<br />
:1 MeV (exactly): Electrons painted with space camouflage<br />
<br />
:10 GeV - 10 TeV: Neutralino<br />
<br />
:100 TeV - 10<sup>-17</sup> kg: Q-ball<br />
<br />
:1 ng - 100 ng: Pollen<br />
<br />
:0.1 mg - 1 mg: No-See-Ums<br />
<br />
:10<sup>-1</sup> g (exactly): Bees<br />
<br />
:10 g - 100 g: 8-balls<br />
<br />
:100 kg - TON: Space cows<br />
<br />
:TON - 10<sup>9</sup> kg: Obelisks, monoliths, pyramids<br />
<br />
:10<sup>9</sup> kg - 10<sup>33</sup> kg: Black holes ruled out by:<br />
::10<sup>9</sup> kg - 10<sup>13</sup> kg: Gamma rays<br />
::10<sup>13</sup> kg - 10<sup>17</sup> kg: GRB lensing<br />
::10<sup>15</sup> kg - 10<sup>22</sup> kg: Neutron star data<br />
::10<sup>21</sup> kg - 10<sup>30</sup> kg: Micro lensing<br />
::10<sup>24</sup> kg - 10<sup>30</sup> kg: Solar system stability<br />
::10<sup>30</sup> kg - 10<sup>33</sup> kg: Buzzkill astronomers<br />
<br />
:10<sup>33</sup> kg - >10<sup>36</sup> kg: Maybe those orbit lines on space diagrams are real and very heavy<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Science]]<br />
[[Category:Physics]]<br />
[[Category:Astronomy]]<br />
[[Category:Line graphs]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2035:_Dark_Matter_Candidates&diff=1615712035: Dark Matter Candidates2018-08-20T15:24:44Z<p>162.158.63.154: /* Explanation */ Fixed unreadably bad grammar in the first paragraph. Also added two more pieces of evidence for dark matter.</p>
<hr />
<div>{{comic<br />
| number = 2035<br />
| date = August 20, 2018<br />
| title = Dark Matter Candidates<br />
| image = dark_matter_candidates.png<br />
| titletext = My theory is that dark matter is actually just a thin patina of grime covering the whole universe, and we don't notice it because we haven't thoroughly cleaned the place in eons.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Every section needs to be filled and explained. Do NOT delete this tag too soon.}}<br />
{{w|Dark matter}} is a hypothetical form of matter used by the vast majority of astronomers to explain the far too high apparent mass of objects at large scales in our universe. In galaxies stars are orbiting faster, implying more gravitational force than the sum of the masses of visible matter could cause and entire galaxies are observed moving much faster around than it should be. In galactic collisions, the mass can appear to separate from the visible matter, as if the mass doesn't collide but the visible matter does. A small galaxies have been observed to not have this property, suggesting that it is a *thing* that a galaxy can have more or less of and is separable from. At scales of our solar system those effects are too small and can't be measured. In cosmology, dark matter is estimated to account for 85% of the total matter in the universe.<br />
<br />
This comic gives a set of possibilities of what dark matter could possibly be, charted by mass from smallest (given in {{w|Electronvolt#Mass|electronvolts}}) to largest (given in kilograms). Masses in the range 10<sup>-15</sup> kg to 10<sup>-3</sup> kg are given in grammes. <br />
<br />
The joke in this comic is that the range of the mass of the possible particles and objects stretch over 81 powers of ten. [[Randall]] filled the gap between real small candidate particles and real large candidate objects with highly absurd suggestions.<br />
<br />
;Axion<br />
An {{w|Axion|Axion}} is a hypothetical elementary particle that might be a component of dark matter.<br />
<br />
;Sterile neutrino<br />
{{w|Sterile neutrino|Sterile neutrinos}} are hypothetical particles interacting only via gravity. It's an actual candidate for dark matter.<br />
<br />
;Electrons painted with space camouflage<br />
Electrons are fundamental particles which compose the outer layers of atoms. A large number of electrons in the galaxy would be relatively easy to detect, as they not only interact with light (which dark matter does not appear to), but have a strong electric charge. Presumably, space camouflage is a positively-charged coating which prevents electrons from interacting with light. (Needless to say, this is not an actual candidate for dark matter.)<br />
<br />
;Neutralino<br />
A {{w|Neutralino|Neutralino}} is a hypothetical particle from {{w|Supersymmetry|Supersymmetry}}, not something made up by Randall Munroe that sounds vaguely like one. It's an actual candidate for dark matter.<br />
<br />
;Q-ball<br />
In theoretical physics, a {{w|Q-ball|Q-ball}} is a stable group of particles. It's an actual candidate for dark matter.<br />
<br />
In billiards, a cue ball is the white (or yellow) ball hit with the cue in normal play.<br />
<br />
;Pollen<br />
{{w|Pollen|Pollen}} is a joke candidate, though people with seasonal allergies may suspect that the universe genuinely is made up entirely of pollen in the springtime. <br />
<br />
;No-See-Ums<br />
{{w|Ceratopogonidae|No-See-Ums}}, also called Ceratopogonidae, a family of small flies (1–4 mm long) who can pass through most window screens. Another joke candidate.<br />
<br />
;8-balls<br />
In pool, the {{w|Pool (cue sports)|8-ball}} is a black ball numbered 8. It's a pun with Q-ball/cue ball. Unless undetected aliens have discovered billiards and become addicted to it, 8-balls are found only on Earth and are, hence, unlikely dark matter candidates.<br />
<br />
;Space Cows<br />
Cows are Bovines extensively farmed on Earth for milk and meat. Although there is folk lore concerning cows {{w|Hey diddle diddle|acheiving circum-lunar orbits}}, they have yet to be found elsewhere in the Universe.<br />
<br />
;Obelisks, Monoliths, Pyramids<br />
While those human constructions are huge on a human scale, they're negligible at universe-scale. It would take a large number of such constructions, distributed through space, to replicate the effects of dark matter; while a scenario could be envisioned where enough such constructs existed, with properties and distribution allowing them to match observations, this is obviously not a likely explanation.<br />
They often show up in fiction and pseudo-scientific literature as alien artifacts generating immense unknown power out of nowhere, with the most famous and influential example being the monolith from 2001: A Space Odyssey.<br />
<br />
;Black Holes ruled out by:<br />
{{w|Black hole|Black holes}} are known in sizes of a few sun masses (about 10<sup>30</sup>-10<sup>31</sup> kg) as remnants of the core of former big stars and the real big ones at the centers of galaxies (millions or even billions of the mass of the sun.) But recent gravitational wave detection indicate that black holes at 50 or 100 sun masses also exist while their origin is still not understood. Randall doesn't mention this but some astronomers hope that these could fill at least a part of the gap.<br />
<br />
Except the last item all range below the mass of the sun (2x10<sup>30</sup> kg) while the smallest known black hole is about four sun masses.<br />
* Gamma Rays: If dark matter were black holes of this size, the black holes would be evaporating in bursts of hawking radiation, and we'd see a buzz of gamma rays from every direction.<br />
* GRB lensing<br />
* Neutron Star Data<br />
* Micro lensing<br />
* Solar System Stability<br />
* Buzzkill Astronomers: Black holes above a certain size would be impossible to miss, due to the effects they have on nearby matter.<br />
<br />
;Maybe those orbit lines on space diagrams are real and very heavy<br />
Any diagram of our solar system (or any solar system) will show lines representing the path the planet takes around its sun. Since planets orbit in ellipses, there will be an ellipse for every planet. This lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be ''huge'' (Earth's would be 940 million km long (2π AU) and Neptune's would be 28 ''billion'' kilometers long. [https://www.youtube.com/watch?v=0fKBhvDjuy0 Powers of Ten (1977)] gives a good sense of just how large these orbit lines need to be in order to be visible in space diagrams. If these orbit lines were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the inner four planets, including the Earth, which would be a problem. Overall, not a very likely candidate.<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
<br />
:Dark matter candidates:<br />
:[A line graph is shown and labeled at left quarter in eV and further to the right in g together with some prefixes.]<br />
:[The labels read:]<br />
:µeV, meV, eV, keV, MeV, GeV, TeV, 10<sup>-18</sup>kg, ng, µg, mg, g, kg, TON, 10<sup>6</sup>kg, 10<sup>12</sup>kg, 10<sup>18</sup>kg, 10<sup>24</sup>kg, 10<sup>30</sup>kg<br />
<br />
:[All items are shown in bars ranging between two approximately values:]<br />
:< 1 µeV - 10 meV: Axion<br />
<br />
:1 eV - 10 keV: Sterile neutrino<br />
<br />
:1 MeV (exactly): Electrons painted with space camouflage<br />
<br />
:10 GeV - 10 TeV: Neutralino<br />
<br />
:100 TeV - 10<sup>-17</sup> kg: Q-ball<br />
<br />
:1 ng - 100 ng: Pollen<br />
<br />
:0.1 mg - 1 mg: No-See-Ums<br />
<br />
:10<sup>-1</sup> g (exactly): Bees<br />
<br />
:10 g - 100 g: 8-balls<br />
<br />
:100 kg - TON: Space cows<br />
<br />
:TON - 10<sup>9</sup> kg: Obelisks, monoliths, pyramids<br />
<br />
:10<sup>9</sup> kg - 10<sup>33</sup> kg: Black holes ruled out by:<br />
::10<sup>9</sup> kg - 10<sup>13</sup> kg: Gamma rays<br />
::10<sup>13</sup> kg - 10<sup>17</sup> kg: GRB lensing<br />
::10<sup>15</sup> kg - 10<sup>22</sup> kg: Neutron star data<br />
::10<sup>21</sup> kg - 10<sup>30</sup> kg: Micro lensing<br />
::10<sup>24</sup> kg - 10<sup>30</sup> kg: Solar system stability<br />
::10<sup>30</sup> kg - 10<sup>33</sup> kg: Buzzkill astronomers<br />
<br />
:10<sup>33</sup> kg - >10<sup>36</sup> kg: Maybe those orbit lines on space diagrams are real and very heavy<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Science]]<br />
[[Category:Physics]]<br />
[[Category:Astronomy]]<br />
[[Category:Line graphs]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2035:_Dark_Matter_Candidates&diff=1615462035: Dark Matter Candidates2018-08-20T13:40:04Z<p>162.158.63.154: </p>
<hr />
<div>{{comic<br />
| number = 2035<br />
| date = August 20, 2018<br />
| title = Dark Matter Candidates<br />
| image = dark_matter_candidates.png<br />
| titletext = My theory is that dark matter is actually just a thin patina of grime covering the whole universe, and we don't notice it because we haven't thoroughly cleaned the place in eons.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Every section needs to be filled and explained. Do NOT delete this tag too soon.}}<br />
This comic gives a set of possibilities of what dark matter could possibly be. In cosmology, {{w|Dark_matter| dark matter}} is an unknown type of matter thought to account for 85% of the total matter in the universe. The joke in this comic is that the range of the mass of the possible particles and objects stretch over 81 powers of ten. Randall filled the gap between small candidate particles and large candidate objects with highly absurd suggestions.<br />
<br />
'''{{w|Axion|Axion}}'''<br />
<br />
A hypothetical elementary particle that might be a component of dark matter.<br />
<br />
<br />
'''{{w|Sterile_neutrino|Sterile neutrino}}'''<br />
<br />
A hypothetical particle interacting only via gravity. It's an actual candidate for dark matter.<br />
<br />
<br />
'''{{w|Electron|Electrons}} painted with space {{w|camouflage|camouflage}}'''<br />
<br />
<br />
'''{{w|Neutralino|Neutralino}}'''<br />
<br />
A hypothetical particle from {{w|Supersymmetry|Supersymmetry}}. It's an actual candidate for dark matter.<br />
<br />
<br />
'''{{w|Q-ball|Q-ball}}'''<br />
<br />
In theoretical physics, a Q-ball is a stable group of particles. It's an actual candidate for dark matter.<br />
<br />
In billiards, a cue ball is the white (or yellow) ball hit with the cue in normal play.<br />
<br />
<br />
'''{{w|Pollen|Pollen}}'''<br />
A joke candidate, though people with seasonal allergies may suspect that the universe genuinely is made up entirely of pollen in the springtime. <br />
<br />
<br />
'''{{w|Ceratopogonidae|No-See-Ums}}'''<br />
<br />
Also called Ceratopogonidae, a family of small flies (1–4 mm long) who can pass through most window screens.<br />
<br />
<br />
'''{{w|Pool (cue sports)|8-balls}}'''<br />
<br />
In billiards, the 8-ball is a black ball numbered 8. It's a pun with Q-ball/cue ball.<br />
<br />
<br />
<br />
'''Space {{w|Cow|Cows}}'''<br />
<br />
<br />
'''{{w|Obelisk|Obelisks}}, {{w|2001: A Space Odyssey (film)|Monoliths}}, {{w|Pyramid power|Pyramids}}'''<br />
<br />
While those human constructions are huge on a human scale, they're negligible at universe-scale.<br />
They often show up in fiction and pseudo-scientific literature as alien artifacts generating immense unknown power out of nowhere.<br />
<br />
<br />
'''Black Holes ruled out by:'''<br />
* Gamma Rays<br />
** If dark matter were black holes of this size, the black holes would be evaporating in bursts of hawking radiation, and we'd see a buzz of gamma rays from every direction.<br />
* GRB lensing<br />
* Neutron Star Data<br />
* Mirco lensing<br />
* Solar System Stability<br />
* Buzzkill Astronomers<br />
<br />
<br />
'''Maybe those orbit lines on space diagrams are real and very heavy'''<br />
<br />
Any diagram of our solar system (or any solar system) will show lines representing the path the planet takes around its sun. Since planets orbit in ellipses, there will be an ellipse for every planet. This lines don't show real objects, though. Astronomers just draw them on pictures of the solar system to show where the planets move. If you draw a line on a map to give someone directions, that line isn't an object in real life; it's just on the map. If these lines were real, they would be huge (Earth's would be 940 million km long (2*pi*AU) and Neptune's would be 28 BILLION kilometers long). If they were also very dense, they would have a huge mass and could possibly account for the missing 85% of the mass in the universe. But they would also constantly be impaling the inner four planets, including the Earth, which would be a problem. Overall, not a very likely candidate. [[User:Yosho27|Yosho27]] ([[User talk:Yosho27|talk]]) 13:04, 20 August 2018 (UTC)<br />
<br />
==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
Dark matter candidates:<br />
<br />
[A list of candidates on a scale. The scale unit starts with energy and ends with mass:]<br />
{| class="wikitable"<br />
!style="width:10%"|Start<br />
!style="width:10%"|End<br />
!style="width:55%"|Candidate<br />
|-<br />
|< µeV<br />
|10 meV<br />
|Axion<br />
|-<br />
|eV<br />
|10 KeV<br />
|Sterile neutrino<br />
|-<br />
|MeV<br />
|MeV<br />
|Electrons painted with space camouflage<br />
|-<br />
|10 GeV<br />
|10 TeV<br />
|Neutralino<br />
|-<br />
|100 TeV<br />
|10^-17 kg<br />
|Q-ball<br />
|-<br />
|ng<br />
|100 ng<br />
|Pollen<br />
|-<br />
|mg<br />
|mg<br />
|No-See-Ums<br />
|-<br />
|10^-1 g<br />
|10^-1 g<br />
|Bees<br />
|-<br />
|10 g<br />
|100 g<br />
|8-balls<br />
|-<br />
|100 kg<br />
|TON<br />
|Space Cows<br />
|-<br />
|TON<br />
|10^9 kg<br />
|Obelisks, Monoliths, Pyramids<br />
|-<br />
|10^9 kg<br />
|10^33 kg<br />
|Black Holes ruled out by:<br />
* Gamma Rays<br />
* GRB lensing<br />
* Neutron Star Data<br />
* Mirco lensing<br />
* Solar System Stability<br />
* Buzzkill Astronomers<br />
|-<br />
|10^33 kg<br />
|> 10^36 kg<br />
|Maybe those oribt lines on space diagrams are real and very heavy<br />
|}<br />
<br />
{{comic discussion}}</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=2034:_Equations&diff=1613902034: Equations2018-08-17T13:41:52Z<p>162.158.63.154: replaced "something dark energy related" with the cosmological constant</p>
<hr />
<div>{{comic<br />
| number = 2034<br />
| date = August 17, 2018<br />
| title = Equations<br />
| image = equations.png<br />
| titletext = All electromagnetic equations: The same as all fluid dynamics equations, but with the 8 and 23 replaced with the permittivity and permeability of free space, respectively.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an EQUATION. Do NOT delete this tag too soon.}}<br />
This comic gives a set of equations supposedly from different areas of science in mathematics, physics, and chemistry. To anyone not familiar with the field in question they look pretty similar to what you might find in research papers or on the relevant Wikipedia pages. To someone who knows even a little about the topic, they are clearly very wrong and only seem even worse the more you look at them.<br />
<br />
;All kinematics equations<br />
:<math>E = K_0t + \frac{1}{2}\rho vt^2</math><br />
{{w|Kinematics}} describes the motion of objects without considering mass or forces.<br />
<br />
This equation here literally states: "Energy equals a constant <math>K_0</math> multiplied by time, plus half of density multiplied by speed multiplied by time squared". The first term here is hard to interpret: it could be correct if <math>K_0</math> is a constant power applied to the system, but this symbol would more normally be used to denote an initial energy, in which case so multiplying by <math>t</math> would be wrong. The second term looks similar to the traditional kinetic energy formula <math>\frac{1}{2}mv^2</math> but with a density instead of the mass. This is then wrong without some accompanying volume term (on either side of the equation). This appears to be a play on the forumula: <math>s = ut + \frac{1}{2}\ at^2</math> where distance travelled (s) in a constantly accelerating environment, is determined by initial velocity (u), time (t) and acceleration (a)<br />
<br />
;All number theory equations<br />
:<math>K_n = \sum_{i=0}^{\infty}\sum_{\pi=0}^{\infty}(n-\pi)(i-e^{\pi-\infty})</math><br />
{{w|Number theory}} is a branch of mathematics primarily to the study the properties of integers.<br />
<br />
Taken literally the equation says: "The nth K-number is equal to: for all i in 0 to infinity, for all pi in 0 to infinity; subtract pi from n, and multiply it with i minus e to the power of pi minus infinity". A twofold misconception can be seen here. The first is the reassignment of pi as a variable instead of the constant (3.14...). This might be a jab at how in number theory letters and numbers are used interchangeably, but where some letters are all of a sudden fixed constants. The second misconception is the use of infinity in the latter part of the formula. Naively this would signify that (with the reassigned pi values) the part in the power would range from minus infinity to zero. However, infinity is not a number and cannot be used as one without using a limit construct.<br />
<br />
;All fluid dynamic equations<br />
:<math>\frac{\partial}{\partial t}\nabla\cdot \rho = \frac{8}{23}<br />
\int\!\!\!\!\!\!\!\!\!\;\;\bigcirc\!\!\!\!\!\!\!\!\!\;\;\int<br />
\rho\,ds\,dt\cdot \rho\frac{\partial}{\partial\nabla}<br />
</math><br />
{{w|Fluid dynamics}} describes the movement of non-solid material. In particular for gases, the density <math>\rho</math> is often the most interesting quantity (for liquids, this is actually just constant). A unique feature of fluid-dynamic equations is the presence of {{w|Advection|advection terms}}, which take the form of often strange-looking spatial derivatives. This equation turns this up to a new level by differentiating with respect to a differential operator <math>\nabla</math>, which does not make any sense at all. Also it has a contour integral which seems reminiscent to a closed-circle process like in a piston engine, but this does not really fit in the context (differential description of a gas), and it has a pair of {{w|Magic number (programming)|unexplained numbers}} <math>8</math> and <math>23</math>, probably alluding to the {{w|Heat capacity ratio|specific heat ratio}} which is often written out as the fraction <math>\tfrac{7}{5}</math>, whereas most other physics equations [[899: Number Line|avoid including any plain numbers higher than 4]].<br />
<br />
;All quantum mechanic equations<br />
:<math>|\psi_{x,y}\rangle = A(\psi) A(|x\rangle \otimes |y\rangle)</math><br />
{{w|Quantum mechanics}} is a fundamental theory in physics which describes the nature at scales of atoms and below. It typically uses the {{w|Bra–ket notation|bra–ket notation}} in its formulas.<br />
<br />
This equation takes a state psi in the dimensions of x and y and equates it to an operator A performed on psi multiplied by the same operator performed on the tensor product of x and y. Seeing as the state psi is already the tensor product of the states x and y, this is equivalent to performing the same unknown operator twice on psi, and unless this operator is its own inverse such as a bit-flip or Hermitian operator, this equation is therefore incorrect.<br />
<br />
;All chemistry equations<br />
:<math>\mathrm{CH}_4 + \mathrm{OH} + \mathrm{HEAT} \rightarrow \mathrm{H}_2\mathrm{O} + \mathrm{CH}_2 + \mathrm{H}_2 \mathrm{EAT}</math><br />
A modification of the combustion of methane. The correct form is often taught and a good example problem but obviously there are more chemistry problems.<math>\mathrm{HEAT}</math> is normally shorthand for {{w|activation energy}}, but in Randall's version it's jokingly used as a chemical ingredient and becomes <math>\mathrm{H}_2\mathrm{EAT}</math>, taking the hydrogen atom freed by the combustion equation shown. To deliver the punchline while maintaining proper stoichiometry, <math>\mathrm{OH}</math> (which should be <math>\mathrm{OH}^-</math>, since the oxygen keeps a free electron when it combines with a single hydrogen) is shown instead of <math>\mathrm{O}_2</math>. The proper methane combustion equation would be: <math>\mathrm{CH}_4 + 2 \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + \mathrm{CO}_2</math><br />
<br />
;All quantum gravity equations<br />
:<math>\mathrm{SU}(2)\mathrm{U}(1) \times \mathrm{SU}(\mathrm{U}(2))</math><br />
This is more similar to experessions which appear in {{w|Grand_Unified_Theory|Grand Unified Theory}} (GUT) than general quantum gravity. Unlike some of the other equations, this one has no interpretation which could make it mathematically correct. This is similar to the notations used to describe the symmetry group of a particular phenomena in terms of mathematical {{w|Lie_Group|Lie Groups}}. A real example would be the Standard Model of particle physics which has symmetry according to <math>\rm{SU(3)\times SU(2) \times U(1)}</math>. Here, <math>\rm{SU}</math> and <math>\rm{U}</math> denote the special unitary and unitary groups respectively with the numbers indicating the dimension of the group. Loosely, the three terms correspond to the symmetries of the strong force, weak force and electromagnetism although the exact correspondence is muddied by symmetry breaking and the Higgs mechanism.<br />
<br />
Of course, an expression missing an "=" sign, is difficult to interpret as an "equation", because equations normally express an "equality" of some kind. Nobody knows whether Randal refers to a horse here (equidae) <br />
<br />
Randall's version clearly involves some similar groups although without the <math>\times</math> symbol it is hard to work out what might be happening. A term like <math>\rm{SU(U(2))}</math> has no current interpretation in mathematics, if anyone thinks otherwise and possibly has a solution to the quantum gravity problem they should probably get in touch with someone about that.<br />
<br />
;All gauge theory equations<br />
:[[File:All gauge theory equations.png]]<br />
This equation looks broadly similar to the sorts of things which appear in gauge theory such as the equations which define {{w|Yang–Mills_theory#Quantization|Yang-Mills Theory}}. By the time physics has got this far in, people have normally run out of regular symbols making a lot of the equations look very daunting. The actual equations in this field rarely go far beyond the Greek alphabet though and no-one has yet to try putting hats on brackets. The appearance of many sub- and superscripts is normal (this links to the group theory origins of these equations) and for the layperson it can be impossible to determine which additions are labels on the symbols and which are indices for an {{w|Einstein_notation|Einstein Sum}}.<br />
<br />
The left-hand side <math>S_g</math> is the symbol for some {{w|Action_(physics)|action}}, in Yang-Mills theory this is actually used for a so-called "ghost action". On the right-hand side we have a large number of terms, most of which are hard to interpret without knowing Randall's thought processes (this is why real research papers should all label their equations thoroughly). The <math>\frac{1}{2\bar{\varepsilon}}</math> looks like a constant of proportionality which often appears in gauge theories. The factor of <math>i = \sqrt{-1}</math> is not unusual as many of these equations use complex numbers. The <math>\eth</math> symbol looks similar to a <math>\partial</math> partial derivative symbol especially as the {{w|Dirac_equation#Covariant_form_and_relativistic_invariance|Dirac Equation}} uses a slashed version as a convenient shorthand. <br />
<br />
The rest of the equation cannot be mathematically correct as the choice of indices used does not match that on the left-hand side (which has none). In particle physics subscripts (or superscripts) of greek letters (usually <math>\mu</math> or <math>\nu</math>) indicate terms which transform nicely under Lorentz transformations (special relativity). Roman indices from the beginning of the alphabet relate to various gauge transformation propetries, the triple index seen on <math>p^{abc}_v</math> would likely come from some <math>\rm{SU(3)}</math> transformation (related to the strong nuclear force). Since <math>S_g</math> has none of these (and is thus a scalar which remains constant under these operations), we would need the right-hand side to behave in the same way. Most of the indices which appear are unpaired and so will not result in a scalar making the equation very wrong. For those not familiar with this type of equation, it is a similar mistake messing up units and setting a distance equal to a mass.<br />
<br />
;All cosmology equations<br />
:<math>H(t) + \Omega + G \cdot \Lambda \, \dots \begin{cases} \dots > 0 & \text{(Hubble model)} \\ \dots = 0 & \text{(Flat sphere model)} \\ \dots < 0 & \text{(Bright dark matter model)} \end{cases}<br />
</math><br />
This is a parody of equations defining the {{w|Hubble's_law#Derivation_of_the_Hubble_parameter|Hubble Parameter}} <math>H(t)</math> although it looks like Randall has become bored and not bothered to finish his equation. Such equations usually have several <math>\Omega</math> terms representing the contributions of different substances to the energy-density of the Universe (matter, radiation, dark energy etc.). In this context <math>G</math> could be Newton's constant and <math>\Lambda</math> is the cosmological constant (energy density of empty space) although seeing them appear multiplied and on the same footing as <math>H</math> is unusual (the dot is entirely unnecessary). Choosing to make <math>H</math> a function of time <math>t</math> and not of redshift <math>z</math> is also unusual.<br />
<br />
The second section looks like the inequalities used to show how what shape the Universe, based on the value of the curvature parameter <math>\Omega_k</math>. A value of 0 indicates a flat Universe (this more or less what we observe) whilst a positive /negative value indicates an open /closed curved Universe. Randall's choice of labels further makes fun of the field as both a flat sphere and bright dark matter are oxymoronic terms which would involve some rather strange model universes.<br />
<br />
;All truly deep physics equations<br />
:[[File:All truly deep physics equations.png]]<br />
<math>\hat H</math> is the Hamiltonian operator, which when applied to a system returns the total energy. In this context, U would usually be the potential energy. However, there is also a subscript 0 and a diacritic making indicating some other variable. Much of physics is based on Lagrangian and Hamiltonian mechanics. The Lagrangian is defined as <math>\hat L = \hat K - \hat U </math> with K being the kinetic energy and U the potential. Hamiltonian mechanics uses the equation <math>\hat H = \hat K + \hat U </math>. The Hamiltonian must be conserved so taking the time derivative and setting it equal to zero is a powerful tool. The principle of least action says allows most modern physics to be derived by setting the time derivative of the Lagrangian to zero.<br />
<br />
==Transcript==<br />
:[Nine equations are listed, three in the top row and two in each of the next three rows. For the bottom equation to the left, there are three equations in one, the part that is different in each equation is given on three lines and a bracket encompassing all three points to three dots indicating the equation continues. Below each equation there are labels:]<br />
<br />
:E = K<sub>0</sub>t + 1/2 pvt<sup>2</sup><br />
:All kinematics equations<br />
<br />
:K<sub>n</sub> = &sum;<sub>i=0</sub><sup>&infin;</sup>&sum;<sub>&pi;=0</sub><sup>&infin;</sup>(n-&pi;)(i-e<sup>&pi;-&infin;</sup>)<br />
:All number theory equations<br />
<br />
:&#x2202;/&#x2202;t &nabla; &sdot; p = 8/23 (&#x222F; &rho; ds dt &sdot; &rho; &#x2202;/&#x2202;&nabla;)<br />
:All fluid dynamic equations<br />
<br />
:|&psi;<sub>x,y</sub>&#x232a; = A(&psi;) A(|x&#x232a;&#x2297; |y&#x232a;)<br />
:All quantum mechanics equations<br />
<br />
:CH<sub>4</sub> + OH + HEAT &rarr; H<sub>2</sub>O + CH<sub>2</sub> + H<sub>2</sub>EAT<br />
:All chemistry equations<br />
<br />
:SU(2)U(1) &times; SU(U(2))<br />
:All quantum gravity equations<br />
<br />
:S<sub>g</sub> = (-1)/(2&epsilon;&#x0304;) i &eth; (&#x302; &xi;<sub>0</sub> +&#x030a; p<sub>&epsilon;</sub> &rho;<sub>v</sub><sup>abc</sup> &eta;<sub>0</sub> )&#x302; f<sub>a</sub><sup>0</sup> &lambda;(3&#x0306;) &psi;(0<sub>a</sub>)<br />
:All gauge theory equations<br />
<br />
:H(t) + &Omega; + G&sdot;&Lambda; ... > 0 (Hubble model) ... = 0 (Flat sphere model) ... < 0 (Bright dark matter model)<br />
:All cosmology equations<br />
<br />
:&#x0124; - u&#x0327;<sub>0</sub> = 0<br />
:All truly deep physics equations<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Science]]<br />
[[Category:Physics]]<br />
[[Category:Math]]<br />
[[Category:Chemistry]]<br />
[[Category:Astronomy]]</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=Talk:2032:_Word_Puzzles&diff=161185Talk:2032: Word Puzzles2018-08-14T16:14:54Z<p>162.158.63.154: </p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
<br />
;Is it a real word puzzle?<br />
Who wants to labouriously check if he's double-bluffed and used an actual word puzzle for this comic? :D [[Special:Contributions/162.158.154.181|162.158.154.181]] 17:45, 13 August 2018 (UTC)<br />
<br />
"Jeopardy" is misspelled in the description. Can someone who is logged in please fix?<br />
Many of the "clue" words can also be rearranged, anagram-wise, to form new words, e.g., parts ≈ strap. {{unsigned ip|162.158.74.243}}<br />
<br />
Most words have 2, 3, 4 or 5 characters. I do not believe, it is a simple crossword puzzle, otherwise he would not fool people. Sebastian --[[Special:Contributions/172.68.110.4|172.68.110.4]] 18:17, 13 August 2018 (UTC)<br />
<br />
;Some thoughts:<br />
*Cueball is messing with Megan and not presenting an answer what the "reminiscent of Jeopardy answers" would imply.<br />
*{{w|Lance Ito}} is a judge well known for the O. J. Simpson murder case.<br />
*{{w|Brian Eno}} is an English musician, composer, record producer, singer, writer, and visual artist. Read the Wiki article to learn more.<br />
*No idea what "Ohio's AirAsia Arena" could imply.<br />
--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:37, 13 August 2018 (UTC)<br />
::Almost all the words in the alt-text / title-text are open to multiple pronunciations from a phonetic standpoint. Often they're placed next to a word containing the same sound with a different spelling, or the same spelling with a different sound. <br />
::Once again Randall is creeping me out with this, as yesterday I complained about the spelling of "tear" with a comment including this line:<br />
::tire tier tear tear tare tar ... teer?<br />
::Randall so often does comics that feel intimately in touch with what I'm doing or saying the day before that it's almost spooky. If I weren't an outlier in so ''many'' scatter plots I might almost begin to feel "ordinary".<br />
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:35, 13 August 2018 (UTC)<br />
<br />
;Moved from the explanation (discussion goes here)<br />
The kind of puzzle that Megan thinks she is solving is called a "Cryptic", which has markedly different rules than ordinary crosswords. If Cueball's statement had been "Part of this aria is an Indian garment" the answer would have been "sari", because a part of the phrase "this aria" is the sequence "sari", which in turn is an Indian garment. Cueball's actual statement contains quite a few familiar cryptic puzzle triggers. The word "composed" can be a hint of a preceding or following anagram, in this case of "this aria" or of "by Brian" or of even longer adjacent strings. Although "opera star" could be a famous singer, say "Caruso", it might also be the name of an opera followed by the name of an astronomical star. "Au pair" could be any of its ordinary meanings, say "nanny", but might also be "earrings" (because AU is the chemical symbol for gold, and a gold pair could be earrings). The word "start" is often a hint to take just the beginning of a word, so "the start" would be "t", or "start of his" would be "h" or "hi". The New York Times runs a cryptic crossword as its "second Sunday puzzle" every other month or so, and there are other regular cryptic crossword venues. In case you are interested, there are various guides on the web for solving cryptics, such as this one at The Atlantic: https://www.theatlantic.com/past/docs/issues/puzzclue.htm. (-- John?)<br />
:This sounds like the most correct explanation to me so far, much moreso than the strictly crossword-based interpretation. I think this ''should'' be in the explanation.<br />
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:44, 13 August 2018 (UTC)<br />
: Why was this moved from the explanation? This is a far better explanation then what remains there. [[Special:Contributions/162.158.38.172|162.158.38.172]] 07:52, 14 August 2018 (UTC)<br />
::I've moved this because it's written like a comment (including the sign). And I think at first we should focus on the ''My Hobby'' thing, Cueball is messing with someone. If you're also ''sure'', like Megan is, that there is a puzzle to solve then Cueball is probably messing you too. Nevertheless all mentioned items and persons have to be explained. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 09:16, 14 August 2018 (UTC)<br />
<br />
Although Randall says he is messing with us, the fact that he is so much cleverer than any of the rest of us means that Cueball's statement might even be a legitimate cryptic clue. --John [[Special:Contributions/108.162.219.214|108.162.219.214]] 18:40, 13 August 2018 (UTC)<br />
<br />
If anyone has an account on https://puzzling.stackexchange.com/, that community might be able to figure out if it's a legit puzzle. [[Special:Contributions/162.158.142.64|162.158.142.64]] 20:59, 13 August 2018 (UTC)<br />
:I just asked at puzzling.stackexchange: https://puzzling.stackexchange.com/questions/69502/is-this-a-puzzle-if-so-what-is-the-solution. [[Special:Contributions/141.101.96.209|141.101.96.209]] 02:03, 14 August 2018 (UTC)<br />
::One answer supports my statement above: "I see no reason to believe this is a puzzle: it's simply a bunch of words that commonly appear in crosswords." Just sayin. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 09:16, 14 August 2018 (UTC)<br />
<br />
Two words: [[Nerd Sniping]] [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:21, 14 August 2018 (UTC)<br />
<br />
:"opera star" = "au pair a[t the] star[t]"? --[[Special:Contributions/162.158.88.230|162.158.88.230]] 07:43, 14 August 2018 (UTC)<br />
<br />
When I first read this sentence, I thought he just wanted to be needlessly verbose for a simple joke, like [https://www.youtube.com/watch?v=oE5KkmDAcDs here]. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 08:16, 14 August 2018 (UTC)<br />
<br />
In the explanation, I think there's a misunderstanding of "post-live". Death is "post-life", while "post-live" is the period after an artist stops performing live (in rock conerts, on stage, etc.). The artist may still be alive, and even produce studio albums. So, according to the comic, Brian Eno has stopped performing on-stage, but has still continued to create music (e.g. compose an aria). - Assaf {{unsigned ip|141.101.107.30}}<br />
: My thoughts exactly - post-live does not mean after death! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 12:44, 14 August 2018 (UTC)<br />
::Thanks for mentioning this. The phrase is still incorrect so I'll do an update. BTW: Is the concert on this album {{w|June 1, 1974}} the last or maybe even the only live performance Eno has done? --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 13:52, 14 August 2018 (UTC)<br />
<br />
I arranged all the important words in the main text on a Scrabble board. The total score of all the letters is 69. The total from my arrangement is 116. {{unsigned|Misterblue28}}<br />
<br />
Reminiscent of the alliterations in BoJack Horseman.<br />
:"Are you still looking for a star for your Transgender Teddy Roosevelt Planes Trains and Automobiles reboot, Plans, Trans, A Canal, Panama?"<br />
<br />
:"You know the actress Courtney Portnoy? She portrayed the formerly portly consort in the seaport resort. Courtly roles like the formerly portly consort are Courtney Portnoy's forte. This was supposed to be Courtney's crossover coronation. But that's sorta been thwarted unfortunately 'cause Courtney's purportedly falling short of shoring up fourth quadrant support."<br />
<br />
:"But Courtney, more importantly, audiences are going to adore your tour de force performance as the forceful denim-clad court reporter in "The Court Reporter Sported Jorts", the jet-setting jort-sporting court reporter story."<br />
<br />
:[[Special:Contributions/162.158.63.154|162.158.63.154]] Steve</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=Talk:2032:_Word_Puzzles&diff=161184Talk:2032: Word Puzzles2018-08-14T16:10:12Z<p>162.158.63.154: </p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
<br />
;Is it a real word puzzle?<br />
Who wants to labouriously check if he's double-bluffed and used an actual word puzzle for this comic? :D [[Special:Contributions/162.158.154.181|162.158.154.181]] 17:45, 13 August 2018 (UTC)<br />
<br />
"Jeopardy" is misspelled in the description. Can someone who is logged in please fix?<br />
Many of the "clue" words can also be rearranged, anagram-wise, to form new words, e.g., parts ≈ strap. {{unsigned ip|162.158.74.243}}<br />
<br />
Most words have 2, 3, 4 or 5 characters. I do not believe, it is a simple crossword puzzle, otherwise he would not fool people. Sebastian --[[Special:Contributions/172.68.110.4|172.68.110.4]] 18:17, 13 August 2018 (UTC)<br />
<br />
;Some thoughts:<br />
*Cueball is messing with Megan and not presenting an answer what the "reminiscent of Jeopardy answers" would imply.<br />
*{{w|Lance Ito}} is a judge well known for the O. J. Simpson murder case.<br />
*{{w|Brian Eno}} is an English musician, composer, record producer, singer, writer, and visual artist. Read the Wiki article to learn more.<br />
*No idea what "Ohio's AirAsia Arena" could imply.<br />
--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:37, 13 August 2018 (UTC)<br />
::Almost all the words in the alt-text / title-text are open to multiple pronunciations from a phonetic standpoint. Often they're placed next to a word containing the same sound with a different spelling, or the same spelling with a different sound. <br />
::Once again Randall is creeping me out with this, as yesterday I complained about the spelling of "tear" with a comment including this line:<br />
::tire tier tear tear tare tar ... teer?<br />
::Randall so often does comics that feel intimately in touch with what I'm doing or saying the day before that it's almost spooky. If I weren't an outlier in so ''many'' scatter plots I might almost begin to feel "ordinary".<br />
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:35, 13 August 2018 (UTC)<br />
<br />
;Moved from the explanation (discussion goes here)<br />
The kind of puzzle that Megan thinks she is solving is called a "Cryptic", which has markedly different rules than ordinary crosswords. If Cueball's statement had been "Part of this aria is an Indian garment" the answer would have been "sari", because a part of the phrase "this aria" is the sequence "sari", which in turn is an Indian garment. Cueball's actual statement contains quite a few familiar cryptic puzzle triggers. The word "composed" can be a hint of a preceding or following anagram, in this case of "this aria" or of "by Brian" or of even longer adjacent strings. Although "opera star" could be a famous singer, say "Caruso", it might also be the name of an opera followed by the name of an astronomical star. "Au pair" could be any of its ordinary meanings, say "nanny", but might also be "earrings" (because AU is the chemical symbol for gold, and a gold pair could be earrings). The word "start" is often a hint to take just the beginning of a word, so "the start" would be "t", or "start of his" would be "h" or "hi". The New York Times runs a cryptic crossword as its "second Sunday puzzle" every other month or so, and there are other regular cryptic crossword venues. In case you are interested, there are various guides on the web for solving cryptics, such as this one at The Atlantic: https://www.theatlantic.com/past/docs/issues/puzzclue.htm. (-- John?)<br />
:This sounds like the most correct explanation to me so far, much moreso than the strictly crossword-based interpretation. I think this ''should'' be in the explanation.<br />
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 22:44, 13 August 2018 (UTC)<br />
: Why was this moved from the explanation? This is a far better explanation then what remains there. [[Special:Contributions/162.158.38.172|162.158.38.172]] 07:52, 14 August 2018 (UTC)<br />
::I've moved this because it's written like a comment (including the sign). And I think at first we should focus on the ''My Hobby'' thing, Cueball is messing with someone. If you're also ''sure'', like Megan is, that there is a puzzle to solve then Cueball is probably messing you too. Nevertheless all mentioned items and persons have to be explained. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 09:16, 14 August 2018 (UTC)<br />
<br />
Although Randall says he is messing with us, the fact that he is so much cleverer than any of the rest of us means that Cueball's statement might even be a legitimate cryptic clue. --John [[Special:Contributions/108.162.219.214|108.162.219.214]] 18:40, 13 August 2018 (UTC)<br />
<br />
If anyone has an account on https://puzzling.stackexchange.com/, that community might be able to figure out if it's a legit puzzle. [[Special:Contributions/162.158.142.64|162.158.142.64]] 20:59, 13 August 2018 (UTC)<br />
:I just asked at puzzling.stackexchange: https://puzzling.stackexchange.com/questions/69502/is-this-a-puzzle-if-so-what-is-the-solution. [[Special:Contributions/141.101.96.209|141.101.96.209]] 02:03, 14 August 2018 (UTC)<br />
::One answer supports my statement above: "I see no reason to believe this is a puzzle: it's simply a bunch of words that commonly appear in crosswords." Just sayin. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 09:16, 14 August 2018 (UTC)<br />
<br />
Two words: [[Nerd Sniping]] [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:21, 14 August 2018 (UTC)<br />
<br />
:"opera star" = "au pair a[t the] star[t]"? --[[Special:Contributions/162.158.88.230|162.158.88.230]] 07:43, 14 August 2018 (UTC)<br />
<br />
When I first read this sentence, I thought he just wanted to be needlessly verbose for a simple joke, like [https://www.youtube.com/watch?v=oE5KkmDAcDs here]. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 08:16, 14 August 2018 (UTC)<br />
<br />
In the explanation, I think there's a misunderstanding of "post-live". Death is "post-life", while "post-live" is the period after an artist stops performing live (in rock conerts, on stage, etc.). The artist may still be alive, and even produce studio albums. So, according to the comic, Brian Eno has stopped performing on-stage, but has still continued to create music (e.g. compose an aria). - Assaf {{unsigned ip|141.101.107.30}}<br />
: My thoughts exactly - post-live does not mean after death! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 12:44, 14 August 2018 (UTC)<br />
::Thanks for mentioning this. The phrase is still incorrect so I'll do an update. BTW: Is the concert on this album {{w|June 1, 1974}} the last or maybe even the only live performance Eno has done? --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 13:52, 14 August 2018 (UTC)<br />
<br />
I arranged all the important words in the main text on a Scrabble board. The total score of all the letters is 69. The total from my arrangement is 116. {{unsigned|Misterblue28}}<br />
<br />
;Reminiscent of the alliterations in BoJack Horseman.<br />
"Are you still looking for a star for your Transgender Teddy Roosevelt Planes Trains and Automobiles reboot, Plans, Trans, A Canal, Panama?"<br />
<br />
"You know the actress Courtney Portnoy? She portrayed the formerly portly consort in the seaport resort. Courtly roles like the formerly portly consort are Courtney Portnoy's forte. This was supposed to be Courtney's crossover coronation. But that's sorta been thwarted unfortunately 'cause Courtney's purportedly falling short of shoring up fourth quadrant support."<br />
<br />
"But Courtney, more importantly, audiences are going to adore your tour de force performance as the forceful denim-clad court reporter in "The Court Reporter Sported Jorts", the jet-setting jort-sporting court reporter story."<br />
<br />
[[Special:Contributions/162.158.63.154|162.158.63.154]] Steve</div>162.158.63.154https://www.explainxkcd.com/wiki/index.php?title=Talk:2030:_Voting_Software&diff=161006Talk:2030: Voting Software2018-08-09T12:58:37Z<p>162.158.63.154: </p>
<hr />
<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
I think this comic is referencing [https://twitter.com/GossiTheDog/status/1026603800365330432 this twitter thread] and the controversy behind it.<br />
[[Special:Contributions/172.69.190.4|172.69.190.4]] 17:59, 8 August 2018 (UTC)<br />
: The [https://arstechnica.com/tech-policy/2018/08/experts-criticize-west-virginias-plan-for-smartphone-voting/ Experts criticize West Virginia’s plan for smartphone voting] article on ArsTechnica has more information (as much as possible when the company in question does not provide any details (note that it is about overseas voting). --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 19:44, 8 August 2018 (UTC)<br />
<br />
Is he saying it's weird that we're so sophisticated in other areas of computer science but so far behind in voting technology, or is he making fun of the idea that electronic voting is somehow inherently unsafe?--[[Special:Contributions/108.162.216.106|108.162.216.106]] 18:10, 8 August 2018 (UTC)<br />
: No i think he is saying computer science is a mess and we should not trust it with voting(he is not making fun of the idea of it being unsafe, he is pressing on the point of it being unsafe[saying that all experts agree on that])18:18, 8 August 2018 (UTC)<br />
<br />
: I think he's commenting on how in most fields, the experts are very sure that they do their job well, and all the angles have been tried and tested, but in computer science the experts are more certain than anyone that there is ''absolutely no way'' for a person to actually build a complex software system with no flaws or vulnerabilities, even if they controlled every aspect of the system. in practice of course they control very little of the system and understand even less of it. [[Special:Contributions/172.68.34.88|172.68.34.88]] 18:22, 8 August 2018 (UTC)<br />
<br />
: He's saying that software development is a terribly buggy process, most likely because the majority of software out there can have bugs without very dire real-world consequences (unlike aircraft or elevators).<br />
<br />
::Not to mention the fact that there are incredibly smart people with great interest in undoing the work that software developers do, whereas that isn't at all the case with airplanes or elevators. [[Special:Contributions/108.162.219.214|108.162.219.214]] 18:29, 8 August 2018 (UTC)<br />
<br />
:: Plus there's the general issue that the public as a whole takes the view that "Computers are majykal" (misspelling deliberate) and therefore somehow automatically safe & infallible, despite experts trying very hard to disillusion people about...pretty much all of that. Compare that to the common assumptions about aircraft and elevators--people need the safety verified, instead of assuming it like they do with computers. [[User:Werhdnt|Werhdnt]] ([[User talk:Werhdnt|talk]]) 19:08, 8 August 2018 (UTC)<br />
<br />
:::There's a logical fallacy here. To compare airplaneS and elevatorS to a voting system program is comparing plural to singular. There would be significant opportunity to break/modify a single instance of those objects, although without the relative anonymity of electronic access involved. Once a computer system is infiltrated, the break-in can be replicated to all instances of that program relatively instantaneously, assuming communication pathways are available.[[Special:Contributions/162.158.75.130|162.158.75.130]] 19:12, 8 August 2018 (UTC)<br />
<br />
::::No logical fallacy; there have been ''multiple'' attempts to get people to accept a voting system program, and the 'done by a computer=infallible' problem is '''''not''''' unique to voting programs. Mr. Babbage was being confused by people who were thinking it was possible to get the correct answers from a computer despite putting the wrong data in back in the 1860s (at least!), and the computer at the time was not much more than a fancy calculator. [[User:Werhdnt|Werhdnt]] ([[User talk:Werhdnt|talk]]) 20:23, 8 August 2018 (UTC)<br />
<br />
A blockchain node doesn't technically need to be connected to the internet in order to function. It needs to have some method for receiving messages from other nodes on the blockchain network, and most blockchain nodes do indeed get these messages via the internet, but some bitcoin nodes (for example) get updates about new blocks and new transactions from the Blockstream satellite. An internet connection is therefore not intrinsically necessary for a blockchain to work, it's just the most convenient way to do it.<br />
<br />
Do you think that this comic had anything to do with the debacle in Johnson County, KS last night? [[Special:Contributions/162.158.62.231|162.158.62.231]] 19:30, 8 August 2018 (UTC)<br />
<br />
The comic ignores the fact that modern airplanes are heavily utilizing software of all kinds. A software failure in an aircraft could easily be fatal (and have been so various times in history already, while the consequences of a voting software working incorrect are ''relatively'' harmless), and still airplanes remain safe, as the comic recognizes. --[[User:YMS|YMS]] ([[User talk:YMS|talk]]) 21:05, 8 August 2018 (UTC)<br />
<br />
:Airplanes are not connected to internet and reasonably well protected from people putting their USB devices in their control system. Also, they are NOT build by lowest bid contractor. There ARE people now capable of building offline voting machine which would be reasonable secure. They are working in banks and stock exchanges and at those companies providing switches for internet backbone, are extremely well paid and wouldn't ever promise they will get the machine finished in single year. Noone asks THEM to make the voting machines. Voting over internet? With consumer-grade devices? Impossible. (I'm also working in IT, although not on mentioned high-security systems.) -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 22:24, 8 August 2018 (UTC)<br />
<br />
::Note that she is talking to aircraft designers, not to software engineers working on fly-by-wire systems (back when I took software engineering you got an answer similar to the one about voting machines when discussing fly-by-wire). I took this more as the aircraft designers glossing over the problems caused by software engineering. A voting system which uses paper ballots, with perhaps computer systems used for some stages of counting would be a reasonable analogy to the redundant systems used in aircraft. [[Special:Contributions/162.158.106.228|162.158.106.228]] 23:08, 8 August 2018 (UTC)<br />
<br />
Seems to me that the last panel references the E.T for Atari Desert Burial (https://en.wikipedia.org/wiki/Atari_video_game_burial), perhaps to draw some analogy as to the potential quality or likelihood of success of a Block-chain solution as compared to the ill-fated video game. Anyone think that's worth explaining? [[User:Da_NKP|Da_NKP]] 10:15, 8 August 2018 (UTC) Da_NKP<br />
<br />
What motive is there to "mine DemocracyCoin"? Who evaluates this blockchain? [[Special:Contributions/162.158.150.100|162.158.150.100]] 22:27, 8 August 2018 (UTC)<br />
:That's simple, ideally it would be a private blockchain, and the evaluators would just be every voting computer in existence (They'd all be active for a similar fairly short time period). Presumably the evaluations would be ongoing during the voting process, then could be stopped once voting was complete. The last few votes of the night may not wind up being evaluated. [[Special:Contributions/162.158.74.225|162.158.74.225]]<br />
<br />
Wouldn't it be possible to run said blockchain on one's personal computer, instead of running on a voting machine? and you could compile open source software yourself to perform the voting. That sounds like a solid enough way to keep security fine to me, but if I'm missing something, please tell me. [[User:Gjgfuj|TheSandromatic]] ([[User talk:Gjgfuj|talk]]) 03:25, 9 August 2018 (UTC)<br />
:The bigger challenge in a voting system isn't making sure someone doesn't modify the record, it's making sure that each person only votes once and only for themselves -- think about past internet voting campaigns: Justin Bieber wasn't sent to North Korea by *changed* votes, but rather by flooding the system with *bogus* votes. [[Special:Contributions/172.68.132.47|172.68.132.47]] 06:26, 9 August 2018 (UTC)<br />
::To be a bit clearer, bitcoin (for example), doesn't and can't enforce that wallets correspond one-to-one with people -- multiple people can share a wallet (if they all know the private key), and one person can have multiple wallets. If you want to guarantee one-to-one correspondence, you have to validate identities and issue unique, signed keys at some prior point. Leaving aside whether or not it's possible to do this part securely and without error (and how big of a target the root signing key would be), you then have millions of people doing their own key management, just like you do with bitcoin. When bitcoin wallets are stolen en masse by key compromises (which does happen), only the wallet owners (who were ostensibly using poor security practices which allowed the compromise) suffer, so the harm is limited. If voting system keys were stolen en masse, but the votes still counted, society as a whole would likely suffer. [[Special:Contributions/172.68.132.47|172.68.132.47]] 07:03, 9 August 2018 (UTC)<br />
<br />
I think a problem that lies within voting machines is that a single flaw can and will be exploited along all machines.<br />
You wouldn't enter a plane if one plane crashing means that all other planes will crash too.<br />
<br />
I am not American and not so inside American politics and its system, but I think there right now is (or just was) some kind of vote in Ohio? Randalls other comic about voting machines, ([[463]])references Ohio directly as well. Even if not, that comic should definitely be referenced here. If no one else does I will in a few hours when I come home from work. [[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 08:11, 9 August 2018 (UTC)<br />
:There was a special election for Ohio's 12th Congressional District on Tuesday to fill in a vacant spot in the US House of Representatives, yes. I hadn't heard anything specifically about any issues with Ohio's voting machines, though I do somewhat vaguely remember Randall making a comic that expressed horror at the fact that a voting machine needed anti-virus software in the first place. [[Special:Contributions/162.158.63.154|162.158.63.154]] 12:58, 9 August 2018 (UTC)<br />
<br />
I guess this may be of interest for reasons why not to have electroni voting https://www.youtube.com/watch?v=w3_0x6oaDmI [[Special:Contributions/162.158.154.13|162.158.154.13]]</div>162.158.63.154