explain xkcd - User contributions [en]

2649: Physics Cost-Saving Tips

2022-07-24T19:53:17Z

162.158.203.16: Undo revision 290551 by Davidy22 the tranny killer (talk)

{{comic
| number = 2649
| date = July 22, 2022
| title = Physics Cost-Saving Tips
| image = physics_cost_saving_tips.png
| titletext = I got banned from the county fair for handing out Helium-2 balloons. Apparently the instant massive plasma explosions violated some local ordinance or something.
}}

==Explanation==
{{incomplete|Created by a FAUX VECTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is another one of [[Randall|Randall's]] [[:Category:Tips|Tips]], this time to reduce costs or provide something for free for physicists to save money on their research. None of these would provide any real advantages even when possible to implement. It continues the previous [[2648: Chemicals]] comic's jocular theme of tricks to supposedly save money based on misinterpretations of science. Obtaining money from physics experiments was also described in [[2007: Brookhaven RHIC]].

{| class="wikitable"
|-
! scope="col" |Cost-Saving Tip
! scope="col" |Explanation
|-
|Try replacing regular vectors with pseudovectors whenever possible
|[[File:Torque animation.gif|frame|right|Relationship of pseudovectors {{w|torque}} ('''τ''') and {{w|angular momentum}} ('''L''') to "regular" Euclidian vectors {{w|Position (vector)|position}} ('''r'''), {{w|force}} ('''F'''), and linear {{w|momentum}} ('''p''') in an oscillatory rotating system. Not shown is the {{w|centripetal force}} of the spoke's {{w|Tension (physics)|tension}}, a Euclidian vector towards the axle proportional to linear momentum, converting it to angular momentum.]]

The prefix "pseudo-" refers to an inauthentic variation of something. Fakes are usually cheaper than their original brand-name product, while often working just as well, so the comic implies a {{w|pseudovector}} could be a less expensive substitute for a regular vector. On the contrary, pseudovectors, or axial vectors, are distinct from regular {{w|Euclidean vector}}s, the former usually being involved with rotation or physical effects that share properties with rotation, similar to the relationship between angles and lengths. Pseudovectors are formed from the {{w|cross product}}s of Euclidean vectors, in three dimensions, and while similar to Euclidean vectors, there is no physical meaning to their specific direction, only their magnitude and portions of their position. For example, {{w|angular momentum}} is described by a pseudovector, labeled '''L''' in the comic, {{w|Normal (geometry)|normal}} to the {{w|plane of rotation}}, originating from the center of rotation, with magnitude equal to the angular velocity of rotation '''ω''' multiplied by the {{w|moment of inertia}} '''I'''. (The comic's diagram is drawn according to very uncommon {{w|Right-hand rule#Coordinates|left-handed coordinates}} instead of the standard {{w|right-hand rule}}. Randall is right-handed.[https://www.youtube.com/watch?v=j1tcyEo2tQk&t=28s])
|-
|A square wave can be broken down into an infinite supply of valuable sine waves
|{{w|Fourier analysis}} can decompose any periodic function into a series of {{w|sine wave}}s. A {{w|square wave}} can thereby be represented as the sum of an infinite series of sine waves. However, the sine waves are not removed or separated individually, so such a {{w|Fourier transform}} does not produce a "supply" of sine waves for practical use in any tasks other than analysis, and as abstract mathematical objects exempt from the laws of supply and demand, their value is similarly limited.
|-
|Cut waste by buying lighter isotopes that don't have any dead-weight neutrons
|Chemical elements are identified by the number of protons in each atomic nucleus, equal to the number of electrons in their shell (unless the atom is ionized), which dictates most of their chemical behavior. {{w|Isotopes}} are variants of the element with different numbers of neutrons in the nucleus, among which chemical behavior is usually nearly identical. The comic suggests that the neutrons don't serve any useful purpose, so, in theory, if purchasing an element by weight, and its isotopes have the same price per unit weight, then you can save money by buying isotopes with no neutrons at all. In reality, the cost per unit weight for material containing a larger concentration of normally rare isotopes, such as {{w|heavy water}} or {{w|enriched uranium}}, is much higher than the cost of material containing isotopes in their ordinary proportions. (An exception is {{w|depleted uranium}}, which costs less than regular uranium because it is a byproduct of the production of enriched uranium.) In addition, a certain range of neutron quantity is needed to keep atoms stable, as atoms with too many or too few neutrons will decay more quickly than the common isotopes. The image shown is helium-2, an {{w|Isotopes of helium|isotope of helium}} which has a half-life of less than a nanosecond. It decays into two ionized hydrogen atoms, releasing a large amount of energy—hence the explosions mentioned in the title text.
|-
|Conductors are a great source of free electrons (may carry charges)
|{{w|Charge carrier|Free}} {{w|electron}}s are electrons that are not tightly bound to specific atoms so they can move freely, such as in {{w|conduction band}}s of the {{w|metallic bond}}s throughout the iron ingot depicted in the comic. Randall interprets "free" in a different sense, meaning no cost. The charges free electrons carry are electric, not monetary as implied by the pun.
|}

In the title text, Randall claims to have been banned from the county fair for handing out helium-2 balloons because of the instant massive explosions caused by its radioactive decay. He jokes they violated a local ordinance. Helium balloons are often given out at county fairs and similar events, but they are filled with helium-4 and therefore inert. A balloon filled with helium-2 is a practical impossibility because of its sub-nanosecond half-life. Assuming a 12-inch diameter balloon at 1 atmosphere of pressure, the balloon-bomb would have a yield of roughly 18 {{w|TNT equivalent|tons of TNT equivalent}}.

{{cot|[[User:SqueakSquawk4|Calcuations]]}}
{{User:SqueakSquawk4}} 
{{cob}}

The smallest nuclear bomb, the {{w|W54}}, had a yield of between 10 and 1,000 tons of TNT. The largest conventional bomb, the {{w|GBU-43/B MOAB}}, has a yield of roughly 11 tons. The {{w|2020 Beirut explosion}} was roughly equivalent to 500 tons of TNT.[https://link.springer.com/article/10.1007/s00193-021-00992-1] So, while the helium-2 balloon bomb would be larger than all conventional bombs, it would still be smaller than most nukes. Handing out what are effectively small atomic bombs at a county fair would not go down well with any surviving local authorities, so merely being banned is a very mild punishment. Criminal charges such as mass murder and terrorism would be more likely if it weren't for the absurd impossibility of the scenario.

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

:[Title]
:Physics Cost-Saving Tips

:[A diagramatical spinning disc, at an angle]
:[It is identified with an 'I', with a dotted axial arrow labelled 'L' and a rotational movement labelled 'ω' (small omega)]
:[It sits on the left, and to the right of this is text...]
:Try replacing regular vectors with pseudovectors whenever possible

:[A square wave with three maxima (between four minima), and arrows pointing down into a collection of five sine waves of different wavelengths]
:[One of the waves having the same frequency as the square wave and the rest of them are of shorter lengths with more peaks and troughs]
:[It sits on the right, and to the left of this is text...]
:A square wave can be broken down into an infinite supply of valuable sine waves

:[Two atomic models]
:[The left containing two protons (white with a "+" sign), two neutrons (black) and orbited by two electrons (small outlines, dotted orbits/movement lines), labelled below with the text of superscript atomic weight and element symbol]
:4He
:[The right model has just the two protons and the two electrons, labelled below with the text of an atomic weight and elemental symbol, and some subtext within brackets]
:2He
:(Decays fast - use quickly)
:[Both models sit on the left of the comic, and to the right is text...]
:Cut waste by buying lighter isotopes that don't have any dead-weight neutrons

:[A flat rectangular bar, drawn in perspective with a scattering of dots/small circles on the top face and on the forward-facing one the label]
:Iron
:[An arrow points to the dots, from the text...]
:Free electrons
:[It sits to the right, and there is text to the left...]
:Conductors are a great source of free electrons
:(May carry charges)

{{comic discussion}}

[[Category:Tips]]
[[Category:Physics]]
[[Category:Chemistry]]

2531: Dark Arts

2021-10-21T10:08:15Z

162.158.203.16: /* Transcript */ Added mouse over - removed incompete notice

{{comic
| number = 2531
| date = October 20, 2021
| title = Dark Arts
| image = dark_arts.png
| titletext = You think, 'okay, THIS is an ideal use case for hardlinks!' but then 6 months later you're doing some extremely cursed Google search like 'javascript ext4' and wondering where things went wrong.
}}

==Explanation==
{{incomplete|Created by a V8-BASED EXT4 FUSE DRIVER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In this comic, [[White Hat]] has presumably just asked [[Cueball]] to perform some task involving {{w|file system|filesystems}}. Cueball responds to this request with an extremely melodramatic monologue, referring to knowledge of the subject as "dark arts" and stating he'd rather not have anything to do with them, as they are too dangerous.

This reaction is reminiscent of a fairly typical scene in e.g. superhero movies, where a person with supernatural powers explains they prefer not to use them, as their use is likely to have negative effects that outweigh the positive ones. Often this is tied to a tragic backstory of the character, where the use of their powers previously caused them or someone close to them much pain and suffering.

A filesystem is the part of a computer's {{w|operating system}} that handles the organisation of data on a (usually) hard drive, splitting it into (usually) files and directories. It is almost invariably a very complicated piece of software. Because of this, it is very easy to make mistakes when interacting with it outside of the most common operations most users would be familiar with, and because it controls practically all of a user's data on a given machine, mistakes made can have very serious consequences (i.e. loss of data). This is probably why Cueball is afraid of messing with them.

{{w|ext4}} is a filesystem in popular use with the {{w|Linux}} operating system kernel. One of its features is the concept of {{w|hard_link|hardlinks}}, which allow two unrelated filenames to refer to the same underlying file. These can be particularly tricky to use, as in nearly all respects they look like regular files, but modifying them can have effects that are not immediately obvious (i.e. by changing the contents of another file). Hardlinks and their misuse have been referenced in xkcd before, as in [[981: Porn Folder]].

The title text hints at an experience Cueball or [[Randall]] has had in the past (his own "tragic backstory", if you will), involving hardlinks on ext4. He thought he had found an ideal use case for them, one which presumably avoided most of their pitfalls, but still, 6 months later, ends up having to troubleshoot some inscrutable bug arising from his decision.

{{w|Javascript}} is a programming language most often associated with web pages. Because of this it is not usually interacting directly with a computer's filesystem, as allowing arbitrary websites to access the filesystem is widely considered an extremely bad idea{{citation needed}}, from a security standpoint. It ''is'' possible to run Javascript directly outside of a browser -- in which case it does have access to common filesystem operations, and even theoretically to the internals of the filesystem -- but since it is a high-level language with poor support for working with the data structures a filesystem uses, this would be a painful, "cursed" way to go about things.

==Transcript==
:[Cueball and White Hat stand in a slightly darkened room, with a jagged circle of light centered on Cueball emanating from the floor and light reflecting onto White Hat's face. Cueball holds his arm out with his palm facing towards White Hat.]
:Cueball: Long ago, in another age, I mastered these dark arts.
:Cueball: But I now endeavor to live my life such that I never need them.
:Cueball: Their power leads only to ruin.
:[Caption below panel]
:My response whenever anyone asks me to mess around with filesystems
:[Mouse over]
:You think, "'okay', this is an ideal use case for hardlinks!", but 6 months later you are doing some extremely curse Google search like 'javascript ext4' and are wondering where things went wrong.

{{comic discussion}}

2525: Air Travel Packing List

2021-10-09T13:10:14Z

162.158.203.16: Citation Needed

{{comic
| number = 2525
| date = October 6, 2021
| title = Air Travel Packing List
| image = air_travel_packing_list.png
| titletext = I know the etiquette is controversial, but I think it's rude when the person in front of me reclines their seat into the bell of my trumpet.
}}

==Explanation==
{{incomplete|Created by an TRUMPETBORNE PARACHUTER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic is another in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}.

The comic is about a proposed air-travel packing list, and the humor stems from the fact that many people have not been flying during the pandemic, and thus they might have forgotten what to pack. So [[Randall]] is so kind as to provide a packing list with 20 items. However, apart from the first item, the rest is not something you would or even should normally bring on an airplane plane.

Many of the items are already found on passenger airplanes, some items would seem like they could be useful on a plane, while other could actually be useful in case of a plane crash (but only if you survive), while many others would be counter-productive to safe air travel, even in the event of a crash. Below in [[#Table of items|the table]] is a quick summary of each item.

The title text references the idea that there is a trumpet for each passenger provided by the airline, which is item number 16 on the list. This items also states that you, because of the covid-19 pandemic, should remember to bring your own mouthpiece for the trumpet as a safety measure.

The trumpet idea is then combined with the common debate regarding reclining your seat in airplanes. About half of the people think that reclining is rude as it takes up the space of the person behind you. The other half think that seats recline for a reason and the person in a seat has the rights to the space behind them. See for instance this [https://www.youtube.com/watch?v=08A30v8isRs video] about such a debate. Reclining a seat has resulted in actual [https://www.independent.co.uk/news/world/americas/crime/fight-airplane-man-punch-video-b1895402.html physical fights] on board airplanes.

Here it seems that Randall sides with the anti-recliners, although maybe only in the context of the comic, because he states that reclining would prevent him from playing his trumpet, as the seat hits the bell of the trumpet. The person in front could certainly argue that playing the trumpet behind them would be very annoying, to which Randall could reply that because the trumpet is provided by the airline, he has the right to play it. This would add a new layer to the debate. This could also be Randall's way of arguing against the right to recline a seat, just because it is possible.

===Table of items===
{| class="wikitable"
! Item
! Explanation
|-
|Seat cushion
|This can be used as a flotation device in a crash and is provided by the airline. Some people may also bring their own cushions for comfort.
|-
|{{w|Parachute}}
|Parachutes are normally used to slow down your falling out of the sky to a relatively safe speed in case of a severe problem with your aircraft, and are routinely used as a safety device by (para)glider pilots, test pilots, military aircraft crew and in similar situations when being unable to land safely is a significant concern. A parachute won't be very useful in a typical passenger airplane (even a small one) as there is no easy way to safely exit such a plane in-flight. Even the airplanes used for {{w|skydiving}} need to be specifically designed or modified for that purpose, such as having wide sliding doors that are unaffected by airflow. However, there were individual cases of people being ejected or sucked out of a passenger airplane, often during partial or complete break-up of the aircraft; in such case a parachute could arguably be useful.{{Citation needed}} Famously, [[:Category:Comics featuring D. B. Cooper|D.B. Cooper]] jumped from an airplane in flight, with a parachute but was never knowingly seen again.
|-
|Wing glue
|Probably to repair wings in the event of damage, potentially in a crash. This would be tricky (but not necessarily impossible) to apply mid-flight. This is the first of several items that are potentially useful to the flight crew or maintenance teams, but would not be useful or appropriate for passengers to bring aboard. Minor repairs (including to the wings) can be made by service personnel using {{w|speed tape}}, tape specially designed for high-speed applications. Speed tape might be mistaken for ordinary duct tape by passengers.
|-
|{{w|Air horn}}
|An air horn uses compressed air to make a very loud noise, very easily. This may be important for drawing attention to yourself in the event of a crash. Typically, emergency life-jackets on a plane are provided with a light and whistle for this purpose. The noise of an air horn might prove more effective for this purpose than a whistle, but it would become useless as soon as the compressed air ran out. Its inclusion is probably meant to suggest that the word 'air' in its name indicates that it's designed for use in an aircraft. Using one in a non-emergency situation would infuriate everyone else on the plane.
|-
|{{w|Sextant}}
|In combination with star charts, a sextant can be used to determine your position based on the location of stars in the night sky. Alternately, in combination with an accurate clock, a sextant can be used to find the position of the sun relative to the aircraft to determine the vehicle's position. In a crash, you could use this to find your way to a safe place, but sextants are rarely used, and most people are not trained on how to operate one. GPS will also allow you to find your position, is built into many phones, and is faster and easier to use than a sextant. If you've got a homing beacon, it probably makes more sense to just activate that and wait for help to arrive.

Until the early 1980s, long-range airplanes had a {{w|Air_navigation#Flight_navigator|flight navigator}} who used sextants and {{w|celestial navigation}} to determine the position of the airplane. Interestingly, it was much more accurate than early {{w|inertial navigation system}}s, and the accuracy of celestial navigation is still useful today. What made the sextant redundant was the INS' lower workload - the error accumulated by the INS during a long oceanic flight could always and easily be mitigated by other means, for example with {{w|VHF omnidirectional range|VOR}}/{{w|Non-directional beacon|NDB}} radio beacons.

A form of the sextant has also famously been used in {{w|Apollo_PGNCS#Optical_units|spacecraft navigation}} and similarly applied {{w|star tracker}}s have been used extensively to guide space-going craft ranging from suborbital missiles to interplanetary probes.
|-
|Nose plugs and goggles for pressure
|Nose plugs and goggles are commonly used in swimming but would be useless for dealing with cabin pressurization or depressurization. Since your mouth and nose are interconnected, nose plugs would be useless on their own. Trying to hold your breath in a sudden depressurization event will cause lung damage, so nose plugs wouldn't be a good thing, even if you could also seal off your mouth. Goggles would also not be useful. During depressurization, the air would just seep out. During pressurization, they would just become uncomfortable and difficult to remove.
|-
|Airplane shoes
|Airlines typically don't require the use of special footwear for passengers, nor do they provide special shoes. Before emergency egress, certain shoes (like high heels) must be discarded, though. Aircrew are also prohibited from wearing such shoes.
|-
|Navigation crystal
|Mystical form of navigation, presumably either for navigation during flight or to help you get home after a crash.
Crystals that polarize light can be used as a compass [http://www.polarization.com/viking/viking.html], but even then, their utility would be limited.
|-
|Spare batteries in case the plane runs out
|Airplanes will generally use more power than any battery small enough to be easily packed in a bag could provide. The aircraft will generally use either 115V AC at 400Hz or 28V DC, both of which are very uncommon outside of aviation. The airplane will almost never use its own batteries in-flight anyway, getting its electric power from the main engines, the APU, or, in emergencies, the ram air turbine or similar generating device. The batteries are generally only used on the ground when the engines are not running.
|-
|{{w|Birdseed}}
|So one can attract birds. In practice, this wouldn't work for multiple reasons (high speed, altitude, and sealed windows being some of most obvious ones) and would pose a significant hazard of birds getting stuck in an engine if it did. Spreading birdseed before boarding ''could'' work to attract birds, but would be seen as misconduct by airport authorities, as attracting birds close to aircraft would pose a danger to the aircraft. Alternatively, birdseed can be used to attract birds after surviving a crash, e.g. to catch them for food.
|-
|{{w|Homing beacon}}
|Once activated, a homing beacon will send out a continuous radio signal so that rescuers can find your location. These can be very useful in a plane crash, but airplanes already carry them ({{w|Emergency position-indicating radiobeacon}}s), so you don't need to pack one yourself. Incidentally, the {{w|COSPAS-SARSAT}} system for locating distressed airplanes and ships was a cooperation started by the United States and the Soviet Union, and it was an elegant and simple solution that uses the {{w|Doppler effect}} of radio signals for accurate location - long before the {{w|Global Positioning System}}.
|-
|Meteorite antidote
|Meteorites are pieces of space rocks that make it all the way to the ground. They can cause injury but they aren't generally poisonous{{Citation needed}}, so an antidote would not help.
|-
|USB wing connector
|This is a just a wire connector, but because it has wing in the name is on the list. Alternatively, the plane wings connect by USB, and this can be used to reattach wings. Airplanes usually use the {{W|ARINC 429}} protocol (or, increasingly, TCP/IP, RS427, RS232, or even CANBUS) instead of USB protocols to facilitate electronic communication between flight computers and the engines, for example.
|-
|Emergency siren
|Very much like air horn, would be useful for helping with locating you in the event of crash. It shares many of the same downsides, but would also more likely get damaged by water in case of a water landing.
|-
|Spare flaps
|Flaps can be moved to adjust the lift/drag ratio of a wing, and are generally deployed during takeoff and landing when the aircraft's speed is slower. Flaps are very large and mounted on the wing, outside the passenger compartment, so bringing spares would be very difficult and completely useless. Flaps failing to deploy can usually be remedied by just landing at a longer runway.
|-
|{{w|Mouthpiece (brass)|Mouthpiece}} (pandemic restriction; airlines still provide the trumpet)
|A part of a brass instrument like a trumpet. Randall jokes that trumpets are provided on airplanes (which would be very obnoxious to other passengers), but due to the pandemic you cannot use a shared mouthpiece. (You shouldn't share mouthpieces for anything anyway, in general.)
|-
|Luggage ballast
|Likely to make plane more balanced. While balancing weight in a plane is indeed a real problem, it is solved by rearranging luggage and adjusting engine power slightly. Introducing ballast would mean additional weight for no real reason.
Alternatively, while a common passenger issue is to have hand- and/or hold-luggage that exceeds the airline's personal allowance, this person has ''under''weight baggage and does not wish to 'waste' the difference, so bulks it up. (Noting that someone already with the rest of the items on this list is unlikely to suffer this 'problem'.)
|-
|Flag (international flights)
|To identify your country of origin. Other flags are also used to communicate between boats without electricity, in the event the boats are in distress, so they could be used in the event of a crash.
|-
|Decoy tickets
|Maybe these would used as a distraction so you can sneak onto the plane without paying?
But also a typical trope for fictional (and real life?) attempts to evade being tracked or followed. Buy tickets for one destination, that one assumes the opposition will be fully aware of, but also arrange for another set (probably with a 'clean' identity) for your intended destination and switch to using those once in the chaos of the departure-lounge.
|-
|Keys to the plane
|Although some people pushed for it after an airplane was stolen in the {{w|2018 Horizon Air Q400 incident}}, most commercial planes do not require keys to start the engine(s) like a car does. Likewise, plane doors are not locked with a key. Instead, they are secured with a tamper seal. If a seal is found broken, the plane is thoroughly checked for any wrong-doing.
|}

==Transcript==
:[A lists of 20 items is given in two columns with 10 items in each. Each item is preceded by a checkbox. Most items only take up one line, but in the left column two items take up two and in the right one item take up three, so they take up the same space. Above is a large heading, with an explanation beneath it.]
:<big><big>Air Travel Packing List</big></big>
:<big>If you haven't flown in a while, you might not remember what you need to bring. Use this handy checklist to pack!</big>

:[Left column:]
:☐ Seat cushion
:☐ Parachute
:☐ Wing glue
:☐ Air horn
:☐ Sextant
:☐ Nose plugs and goggles for pressure
:☐ Airplane shoes
:☐ Navigation crystal
:☐ Spare batteries in case the plane runs out
:☐ Birdseed

:[Right column:]
:☐ Homing beacon
:☐ Meteorite antidote
:☐ USB wing connector
:☐ Emergency siren
:☐ Spare flaps
:☐ Mouthpiece (Pandemic restriction; airlines still provide the trumpet)
:☐ Luggage ballast
:☐ Flag (International flights)
:☐ Decoy tickets
:☐ Keys to the plane

{{comic discussion}}

[[Category:COVID-19]]
[[Category:Animals]]

2519: Sloped Border

2021-09-23T07:37:37Z

162.158.203.16: corrected some spelling errors

{{comic
| number = 2519
| date = September 22, 2021
| title = Sloped Border
| image = sloped_border.png
| titletext = "The slope will be 74° at ground level." "Okay, I think we can hack together a ... wait, why did they specify ground level? It's 74° everywhere, right? ... Oh no, there's a whole section in the treaty labeled 'curvature.'"
}}

==Explanation==
{{incomplete|Created by a SUBSIDING GERRYMANDER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
Every single country demarcates an {{w|international border}} with other countries. The borders are established through law, treaty or consensus. Establishing an international border is very necessary for customs, immigration and security checks. Some countries (like {{w|Cyprus}}) have established a {{w|buffer zone}} in place of an international border to gain additional protection during a conflict.

In this comic, Cueball and Blondie established a "sloped" international border through a treaty. Usually borders are perpendicular to the ground so that all the air(space) above the ground belongs to the same country. This is called {{w|Air sovereignty}}. Thus it suffices to define the border on the earth surface, as 2D lines. The precise definition is that a line from the center of the Earth through the point of the border is drawn. Thus if the terrain is sloped then the border of the air sovereignty does form a sloped line with the terrain.

If the borders were sloped (with respect to the horizontal ground level) an airplane would need to know its precise height to decide which country's rules currently apply. With the help of the {{w|Global Positioning System}} this would be in principle possible, although the height information of GPS is less reliable. The mathematical computation for an angled air sovereignty is relatively straight-forward and could be expressed with a single line of code. However, if the line is curved (as indicated by the mention of curvatures in the title text), the math may get very complicated.

==Transcript==
:[Cueball and Blondie are standing on a podium either for TV, or for the photo op when signing a treaty. They are holding a document together between them. In the background are two informational graphics.]
:Cueball: With this treaty, we are proud to announce the creation of the world's first '''''sloped''''' international border!

:[Caption below frame:]
:If I'm ever put in charge of a country, I'm going to spend all my time trying to think of new ways to make life a nightmare for GIS people.
{{incomplete transcript|Do NOT delete this tag too soon.}}
{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Blondie]]
[[Category:Multiple Cueballs]]
[[Category: Geography]]

Talk:979: Wisdom of the Ancients

2021-09-03T04:16:42Z

162.158.203.16:

"There was uh, a thing called a segfault that made my computer like, all blurry and stuff." '''[[User:Davidy22|Davidy22]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 06:58, 2 February 2013 (UTC)

That was one reason why [http://stackoverflow.com/ StackOverflow] came to life: main authors fed up with (mis)using forums for query & answer site --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 23:03, 15 June 2013 (UTC)

Just two googling steps brought me here:
http://www.mirrorsoferis.com/forum/thread05232003a.html
Relevant for "Trivia"? Even the year fits! [[Special:Contributions/108.162.230.89|108.162.230.89]] 11:28, 12 September 2014 (UTC)
:From the HTML source:
::<tt>
::
::
::</tt>
:Cute theory, though. -[[Special:Contributions/108.162.254.126|108.162.254.126]] 12:23, 10 December 2014 (UTC)
::Even better, looking at other stuff in that source:
:: <td><input class="button" value="Log in" tabindex="104" title="Enter your username and password in the boxes provided to login, spin round three times, vomit, click your heels together and TA-DA!" accesskey="s" type="submit"></td>
:: Will this actually enter properly, or will those formatted tags not be input scrubbed? Tables ... [[User:Keybounce|Keybounce]] ([[User talk:Keybounce|talk]]) 08:34, 4 August 2017 (UTC)

:::Also, someone in 2003 couldn't have asked about a webcomic that was only launched in 2005. [[Special:Contributions/173.245.52.109|173.245.52.109]] 18:29, 3 October 2017 (UTC)

The link above seems to be dead now. DNS failed. [[Special:Contributions/162.158.167.15|162.158.167.15]] 09:03, 22 August 2016 (UTC)
: Working now --[[User:Keybounce|Keybounce]] ([[User talk:Keybounce|talk]]) 08:34, 4 August 2017 (UTC)

2nd paragraph of the explanation is nonsense! A forum post is nothing like a FAQ entry. The problem didn't get solved and was probably put away and forgotten. Happens all the time. {{unsigned ip|162.158.83.144}}

"The title text is a suggestion to forums to be aware of the fact that people are likely going to come across such posts in the future" My pet peeve is when I Google an error and get led to a post like in the comic, and one of the last comments is a person necro-bumping with new information on the same issue, but then a moderator locks the post because its X years old and needs to be left alone. This is the fucking Internet; data doesn't rot. [[Special:Contributions/108.162.212.83|108.162.212.83]] 13:52, 15 July 2017 (UTC)
: From my experience the top search result on google usually is a locked post with no answer (other than the polite suggestion to google it yourself). [[Special:Contributions/162.158.203.16|162.158.203.16]] 04:16, 3 September 2021 (UTC)

Talk:979: Wisdom of the Ancients

2021-09-03T04:15:19Z

162.158.203.16:

Talk:979: Wisdom of the Ancients

2021-09-03T04:14:47Z

162.158.203.16:

"There was uh, a thing called a segfault that made my computer like, all blurry and stuff." '''[[User:Davidy22|Davidy22]]'''[[User talk:Davidy22|<tt>[talk]</tt>]] 06:58, 2 February 2013 (UTC)

That was one reason why [http://stackoverflow.com/ StackOverflow] came to life: main authors fed up with (mis)using forums for query & answer site --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 23:03, 15 June 2013 (UTC)

Just two googling steps brought me here:
http://www.mirrorsoferis.com/forum/thread05232003a.html
Relevant for "Trivia"? Even the year fits! [[Special:Contributions/108.162.230.89|108.162.230.89]] 11:28, 12 September 2014 (UTC)
:From the HTML source:
::<tt>
::
::
::</tt>
:Cute theory, though. -[[Special:Contributions/108.162.254.126|108.162.254.126]] 12:23, 10 December 2014 (UTC)
::Even better, looking at other stuff in that source:
:: <td><input class="button" value="Log in" tabindex="104" title="Enter your username and password in the boxes provided to login, spin round three times, vomit, click your heels together and TA-DA!" accesskey="s" type="submit"></td>
:: Will this actually enter properly, or will those formatted tags not be input scrubbed? Tables ... [[User:Keybounce|Keybounce]] ([[User talk:Keybounce|talk]]) 08:34, 4 August 2017 (UTC)

:::Also, someone in 2003 couldn't have asked about a webcomic that was only launched in 2005. [[Special:Contributions/173.245.52.109|173.245.52.109]] 18:29, 3 October 2017 (UTC)

The link above seems to be dead now. DNS failed. [[Special:Contributions/162.158.167.15|162.158.167.15]] 09:03, 22 August 2016 (UTC)
: Working now --[[User:Keybounce|Keybounce]] ([[User talk:Keybounce|talk]]) 08:34, 4 August 2017 (UTC)

2nd paragraph of the explanation is nonsense! A forum post is nothing like a FAQ entry. The problem didn't get solved and was probably put away and forgotten. Happens all the time. {{unsigned ip|162.158.83.144}}

"The title text is a suggestion to forums to be aware of the fact that people are likely going to come across such posts in the future" My pet peeve is when I Google an error and get led to a post like in the comic, and one of the last comments is a person necro-bumping with new information on the same issue, but then a moderator locks the post because its X years old and needs to be left alone. This is the fucking Internet; data doesn't rot. [[Special:Contributions/108.162.212.83|108.162.212.83]] 13:52, 15 July 2017 (UTC)
: From my experience the top search result on google usually is an locked post with no answer (other than the polite suggestion to google it yourself).

1698: Theft Quadrants

2021-08-31T14:39:43Z

162.158.203.16: /* Explanation */

{{comic
| number = 1698
| date = June 24, 2016
| title = Theft Quadrants
| image = theft quadrants.png
| titletext = TinyURL was the most popular link shortener for long enough that it made it into a lot of printed publications. I wonder what year the domain will finally lapse and get picked up by a porn site.
}}

==Explanation==
This is an {{w|Time management#The Eisenhower Method|Eisenhower box}} comparing how difficult it is to steal a specified object with the severity of the theft.

It is very hard to steal {{w|Gold Codes|nuclear launch codes}}. They are protected by many layers of federal security. That's a good thing, too, since if they were stolen, they could be used to start a {{w|Nuclear warfare|nuclear war}}, which would cause untold death and destruction.

It is also hard to steal the {{w|Crown Jewels of the United Kingdom|Crown Jewels}}, since they are protected by a complex security system. But if they were stolen, it wouldn't be so bad for most people; the only direct loss would be to its owners, the British royal family, who are well-insured for thefts and only use the Crown Jewels as a display piece for museumgoers. It would also be a loss to the public as a cultural and historical artifact, but would have little practical effect on the world.

It wouldn't be too hard to steal the {{w|Wienermobile}}{{Citation needed}} (a car shaped like a hot-dog, advertising the Oscar Mayer brand). There are several versions of this car, and it would not be more difficult to steal than any other car, although harder to hide. [[Randall]] seems to consider that such a stolen vehicle would not be too bad, although he has previously referred to a stolen Wienermobile in [[935: Missed Connections]], which is driven recklessly, almost hitting someone. But it is not bad enough to consider it a big problem in a context when it is compared with stolen nuclear launch codes.

It also wouldn't be hard (or at least, not as hard as stealing nuclear launch codes or the Crown Jewels) to steal the {{w|TinyURL|tinyurl.com}} domain name, but the consequences of that could be significant and is thus listed under very bad. The joke is of course that this is listed as just as bad as the risk of a nuclear war, and of course it is not as significant, but it could swiftly result in damage to a lot of important computers, and ruin references in journals etc.

TinyURL offers a URL shortening service. They provide short URLs that redirect to long ones. This is useful if you want to write down a very long URL as it saves typing and is more accurate. Other companies, including [https://bitly.com/ bit.ly], [https://goo.gl/ Google] (ultimately fully discontinued March 30, 2019), and [https://t.co/ Twitter] offer a similar service. TinyURL was, for a while, the most popular of these URL shortening services. If their domain name were stolen, all the redirects from short URLs could be changed to forward traffic to sites hosting, for example, malware. This would have significant effects on a large number of people, because TinyURL is used in many places both online and (as the title text notes) even sometimes offline.

In the title text Randall implies that stealing the tinyurl.com domain could happen when it next expires. A [https://reports.internic.net/cgi/whois?whois_nic=tinyurl.com&type=domain whois search] as of February 2021 finds that the tinyurl.com domain is next due for renewal in January 2029. However, [https://www.icann.org/resources/pages/expired-2013-05-03-en rule changes made by ICANN] (the organization in charge of domain name registrations) now make it effectively impossible to steal a domain name because the owner allowed its registration to lapse. Current rules for .com registrations now allow for the original owner to renew their domain name after it expires during a 0-45 day auto-renew grace period. The exact length of this grace period depends on what company the domain is registered with. All registrars are then required to give a 30 day redemption grace period during which the domain may be renewed with penalty. As a result, tinyurl.com would have a 30-75 day period after expiration during which the domain is not available for registration by a third party. ICANN rules state that DNS resolution must be stopped during the redemption grace period, which means that there will be a 30 day period during which tinyurl.com will no longer work but the company will have the ability to quickly restore ownership of their domain. It is very unlikely that any company that is still in business would not notice that their domain name has expired before the end of the 30 day redemption grace period.

Another way to steal a domain name would be through {{w|Domain hijacking|domain name hijacking}}. There have been some high profile cases of domain name hijacking, with one of the more notable domains being [http://www.computerworld.com/article/2595655/networking/companies-point-fingers-over-nike-web-site-hijacking.html nike.com in 2000]. However, whether or not this is a risk for any particular domain name is difficult to estimate. Additional security mechanisms such as domain name locking and private registrations have been introduced to mitigate the threat of domain name hijacking. Further, domain name hijacking relies on situation-specific attacks such as hacking email accounts, spoofing emails, and social engineering attacks against either the company who owns the domain name or the company who registers the domain name. For security-conscious companies, such attacks can be impossible, or at least an attacker's success may require security failures in more than one area. A summary of domain hijacking examples including an analysis of how they succeeded and what steps could have prevented them can be found [http://archive.icann.org/en/announcements/hijacking-report-12jul05.pdf here]. In short though, there is no way to say for sure how vulnerable any particular domain name might be to hijacking.

==Transcript==
:[A chart with an Eisenhower box, consisting of four labelled squares. To the left the rows are labelled hard and easy and two lines goes to from these labels to a description of what the labels refer to saying "how hard thing would be to steal". On the bottom the rows are labelled not that bad and very bad and two lines goes to from these labels to a description of what the labels refer to saying "how bad it would be if someone stole it". The top left box is labelled "the Crown Jewels". The top right box is labelled "the nuclear launch codes". The bottom left box is labelled "the Oscar Mayer Wienermobile. The bottom right box is labelled "the tinyurl.com domain name".]

{{comic discussion}}

[[Category:Charts]]
[[Category:Nuclear weapons]]