explain xkcd - User contributions [en]

Talk:2628: Motion Blur

2022-06-04T14:07:01Z

172.70.135.98:

Personally, I'm animated on twos but make up for it with good smear frames. [[Special:Contributions/172.70.135.98|172.70.135.98]] 14:07, 4 June 2022 (UTC)

2625: Field Topology

2022-05-31T17:56:35Z

172.70.135.98: Undo revision 284763 by 162.158.107.52 (talk)

{{comic
| number = 2625
| date = May 27, 2022
| title = Field Topology
| image = field_topology.png
| titletext = The combination croquet set/10-lane pool can also be used for some varieties of foosball and Skee-Ball.
}}

==Explanation==
{{incomplete|Created by A DONUT, OR WAS IT A COFFEE MUG? Please check the new first paragraph, especially the end. And maybe move the mathematical fields/Fields Medal diversion to a footnote. Do NOT delete this tag too soon.}}

Field Topology is [https://encyclopediaofmath.org/wiki/Topological_field a subject in mathematics], but in this comic, Randall is instead examining the topology of playing fields used for various sports. The comic strip depicts a situation in which the common practice of multi-use athletic facilities has been organized by the "topology department" and constructed to be shared by all sports whose normal playing fields are {{w|topology|topologically equivalent}}. One key assumption in topology is that you can ignore the specificities of shape, size and material of the objects concerned. This presents an amusing contrast with the actual activities listed in the comic, where the size and shape of hoops, nets and bars and the material of the field itself are very significant.{{Citation needed}}

(Not to be confused with {{w|Field (mathematics)|mathematical fields}}, or the {{w|Fields Medal}} prize -- although the concept is likely a further pun in the comic, as math (including topology), and most things once can imagine really, are mostly performed ("played") within mathematical fields.).

In topology, shapes which can be smoothly deformed into one another without adding or removing holes are considered equivalent. Note that a topological hole is an area of the nominal space (or area, or other manifold) through which nothing restricted to this topology can pass. In describing a real-world archway, for example, this would be where the material of the arch is, not the actual 'hole' passing ''through'' the constructed arch, which is the path that one indeed may (or must!) pass through to get from one region of the layout to another. A loop is a path across the allowable territory of a topology (or a viable circuit to make through the world it describes) that end up where it started. If a loop cannot be tightened (ultimately adjusted to take a shorter path) down to a single point, then it must be wrapped around at least one 'topological hole' (i.e., through a physical one), and you have separately unique paths (or points, i.e., on different disconnected topologies) where you cannot adjust one loop to take the route of another without severing a looped path and reconnecting it.

{{w|Baseball}} and {{w|tetherball}} are played on fields without any holes that the ball or players can completely pass through (Randall apparently considers nets to be continuous surfaces rather than having many holes), so they are grouped on the sign (i.e., topologically) into one continuous field without holes. The goals on a {{w|soccer}} field presumably do not create holes because the goalposts and crossbar are connected to the field by the net, so the goals and field are topologically equivalent to a smooth disc. Any path taken into and out of the goal (any number of times) is topologically equivalent to one that does not go into this pocket of space at all.

{{w|Volleyball}} and {{w|badminton}} are played using a net suspended from poles, and the {{w|high jump}} has a bar that contestants jump over. The space bounded by the bottom of the net or bar, the supporting poles, and the ground can be considered to be a hole, as a path over and under the net/bar cannot be simplified to one that does not, so their playing fields in the comic all have one "hole".

A basketball court has two holes, the hoops. Parallel bars can be thought of as two rectangles and thus as two topographical "holes". Both have opportunities to pass through either (or both) structures, and so the material of the structures define a hole in the topological abstract of the playing 'surface'. Since we are told that these sports fields belong to the Topology Department - and are not necessarily generalized to all sports fields - we might assume that their "football" field is either for {{w|Rugby_sevens|rugby}} or for American football using H-shaped {{w|Goal (sports)|uprights}}.

The lane dividers in a swimming pool rise out of the water at each end and so create many bounded holes on the 'playing surface', and each hoop in croquet is a hole with one edge bounded by the playing surface. Similarly, as mentioned in the title text, this configuration is also {{w|homeomorphism|homeomorphic}} to a {{w|foosball}} table (with each rod sustaining the player figures above the table defining a hole) or a {{w|Skee-Ball}} lane (which is even more straightforward, as it is just a plane with several holes in which to throw balls). These "playing surfaces" don't actually have the same number of holes, but are apparently lumped together by the Topology Department as having "many" holes.

Unfortunately, the Topology Department does not seem to have a field for {{w|hurdling}} events.

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

:[A row of four signs, each held up by two posts, followed by a row of four rounded lozenge shapes, one for each sign. The signs and lozenge shapes are shaded as if three-dimensional objects, all being flattish with a small third dimension; the four lozenge shapes each have one pair of sides horizontal and the other pair at a slight angle from vertical, denoting a horizontal plane perpendicular to the signs extending "out" towards the viewer, which places each shape "in front" of its sign. All but the first lozenge shape have various numbers of ellipses within the shape - ovoids shaded to denote holes piercing through the objects.]

:[Leftmost sign:]
:Baseball
:Soccer
:Tetherball
:[The shape below this sign contains no ellipses.]

:[Second sign from left:]
:Volleyball
:Badminton
:High jump
:[This shape has one large ellipsis in the center.]

:[Third sign:]
:Basketball
:Football
:Parallel bars
:[This shape has two large ellipses - one in the top half and one in the bottom half.]

:[Fourth and rightmost sign:]
:Olympic swimming
:Croquet
:[This shape has nine small ellipses - eight arranged symmetrically towards the edges of the shape and one in the center.]

:[Caption underneath the signs and shapes:]
:No one ever wants to use the topology department's athletic fields.

{{comic discussion}}
[[Category:Math]]
[[Category:Sport]]

Talk:2553: Incident Report

2021-12-13T16:11:10Z

172.70.135.98: incident 9603120071

It seems that "juggling pins" is also a common term for them. Many websites selling them call them pins. Wikipedia says they "sometimes are referred to as pins or batons by non-jugglers". Presumably the technician writing the IR is not a juggler. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 23:00, 10 December 2021 (UTC)

I'm going to assume that 12/10/2021 is the [https://xkcd.com/1179/ flawed American date system]? [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 23:01, 10 December 2021 (UTC)

You have read The Leaky Establishment. Dave Langford always claims he did not smuggle nuclear material out, but will admit to a filing cabinet. [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 23:09, 10 December 2021 (UTC)

''strictly regulated control rooms which would prevent the simultaneous presence of fireworks, juggling and birthday celebrations'' - I would hope that in control room of nuclear power plants, fireworks, juggling and birthday celebrations can't be present AT ALL, not just simultaneously ... -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 23:15, 10 December 2021 (UTC)
: You might think that, but I'm basing my edits on that documentary of modern American life entitled "The Simpsons" [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 11:23, 11 December 2021 (UTC)

: As an operator at a nuclear power plant I can tell you that birthday cake is not infrequently present in the control room. But yeah, juggling would be quite discouraged, and security would not be happy if you tried to bring fireworks into the Protected Area. Also, for the record, I have never heard the fuel rods called "pins" (though that may be regional), and while the description of fuel rods here isn't *technically* false I think that "control rods" are what the writer was attempting to describe. (The design of the fuel rods does of course effect neutron flux et al, but they are not positionable or anything like that so to say that they "control reaction speed" is rather misleading.) --[[Special:Contributions/172.70.126.65|172.70.126.65]] 12:23, 11 December 2021 (UTC)
:: I take your point and greater knowledge and so have more precisely linked to the wikipedia page from which I gained such knowledge [[User:Kev|Kev]] ([[User talk:Kev|talk]]) 20:16, 11 December 2021 (UTC)

It's perhaps worth noting that the comic was posted within hours of Amazon in real life releasing an incident report for a major outage of one of their server locations which affected many of their services, perhaps explaining how an Amazon delivery worker accidentally delivered fireworks to the wrong location. [[Special:Contributions/172.70.110.173|172.70.110.173]] 02:36, 11 December 2021 (UTC)

It's never specified to be a ''birthday'' cake, but I don't know how to put that in the explanation. [[Special:Contributions/172.70.175.80|172.70.175.80]] 03:05, 11 December 2021 (UTC)Bumpf
*The third paragraph says "a birthday cake intended for Technician B". --[[Special:Contributions/172.70.130.205|172.70.130.205]] 04:55, 11 December 2021 (UTC)

Noting that Randall is not above drilling down even to decimals (or subunits) of seconds as needed. Relarivistic Baseball and Vlass Half Empty come immediately to mind. But I'm not sure if he's gone down the Xeno's Paradox route of starting off fairly long-scale and as the finale approaches cutting down the gap between each itemisation and the next to finer and finer distictions. Wouldn't be surprised if he did, but I'd have to search for it.
[[Special:Contributions/172.70.85.227|172.70.85.227]] 03:45, 11 December 2021 (UTC)

I don't think that "false minute-level precision" is correct here. In fact, the next more precise-looking times might actually be false precision: go to https://en.wikipedia.org/wiki/False_precision to see what I mean. I don't know how to express the changing precision indications, however . . . . [[Special:Contributions/172.70.126.87|172.70.126.87]] 11:32, 11 December 2021 (UTC)

I suppose '' [https://en.m.wikipedia.org/wiki/Seconds_from_Disaster Seconds From Disaster]'' is just the kind of show this would end up on... [[User:IByte|IByte]] ([[User talk:IByte|talk]]) 15:21, 11 December 2021 (UTC)

(1) Although anonymous, it appears that we know it's Technician B's birthday which is quite personally identifiable and (2) I want more follow up about the kittens, for public safety. We could be looking at a new animal martial arts franchise but I can't decide if that's the best case or worst. [[Special:Contributions/172.70.85.41|172.70.85.41]] 15:50, 11 December 2021 (UTC) Robert Carnegie rja.carnegie@gmail.com
:...they've possibly already got a more {{w|Samurai Pizza Cats|direct competition}}. (See also {{w|Bucky O'Hare|other}} {{w|Streaky the Supercat|examples}} for the generally furry, if not feline, if you prefer. ;) ) [[Special:Contributions/162.158.159.43|162.158.159.43]] 16:55, 11 December 2021 (UTC)

Is there an xkcd fanfic site where the story continues? I sure would love to read what happens at the microsecond level. How detailed will the story get? Femtosecond maybe? Ah such suspense! [[User:Ralfoide|Ralfoide]] ([[User talk:Ralfoide|talk]]) 18:18, 11 December 2021 (UTC)
:Heisenberg might have something to say about getting too precise. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 13:55, 12 December 2021 (UTC)
::Schrödinger's opinion on this might be anything. Has anyone checked yet? [[Special:Contributions/172.70.162.155|172.70.162.155]] 16:46, 12 December 2021 (UTC)

If the end result was any injury that required medical attention or a reactor SCRAM there would be an incident report. A SCRAM would be more likely to have accurate timestamps from the logs. So it is possible that the incident report is for a fairly minor result. [[Special:Contributions/162.158.107.40|162.158.107.40]] 14:41, 12 December 2021 (UTC)

Was this inspired by the pretty serious Log4Shell (cve-2021-44228) that came out exactly that day (2021/12/10)? Can assure you many incident reports were written that day [[Special:Contributions/162.158.233.53|162.158.233.53]] 10:18, 13 December 2021 (UTC)

who decided to put some of their unreobtainable time into that incomplete tag? also, thank you to whoever did that [[User:Lettherebedarklight|https://www.youtube.com/watch?v=miLcaqq2Zpk]] ([[User talk:Lettherebedarklight|talk]]) 12:05, 13 December 2021 (UTC)

Astonishingly, incident 9603120071 wasn't previously mentioned on Onofre Nuclear Generating Station's Wikipedia page. It is now! [[Special:Contributions/172.70.135.98|172.70.135.98]] 16:11, 13 December 2021 (UTC)

2553: Incident Report

2021-12-10T22:54:33Z

172.70.135.98:

{{comic
| number = 2553
| date = December 10, 2021
| title = Incident Report
| image = incident_report.png
| titletext = Increasing-precision timestamps are the Jaws theme of incident reports.
}}

==Explanation==
{{incomplete|Created by an OVERLY-PRECISE TEMPORAL SHARK - Title-text still pending, and particularly bare-bones explanation for first draft. Do NOT delete this tag too soon.}}

An {{w|incident report}} describes the events that happen before something goes wrong; this usually involves describing what time related events happen at. In this comic, a report at a {{w|nuclear power plant}} starts with particularly vague timestamps (that a package of fireworks arrived "roughly 18 hours prior" to it), then uses false minute-level precision ("14:00" and "14:20", which could reasonably be five minutes off in either direction), then actual minute-level precision ("14:28"), then second-level precision ("14:29:22" and "14:29:26").

This suggests that the ''clock'' time is really a proxy for the ''amount'' of time before one specific moment where everything falls apart, and when seconds start appearing, it implies that the recollection is within a few minutes of the disaster. Normally the increased level of precision reflects close monitoring capabilities of the affected system and/or detailed analysis by incident investigators.

Examples of real-life incident reports with second-level precision timestamps showing the increasing prevision around critical moments include:
* [https://spaceflightnow.com/challenger/timeline/ Explosion] of the Space Shuttle Challenger
* [https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/appendices/chernobyl-accident-appendix-1-sequence-of-events.aspx Chernobyl explosion]

Although the comic refers to {{w|Juggling club|juggling "pins"}}, jugglers commonly refer call those props as "clubs." It is possible Randall is confusing the {{w|Bowling pin|similarly shaped objects}} in 10-pin bowling to juggling clubs. "Pins" are another name for {{W|nuclear fuel rod}}s.

The title text refers to the [https://www.youtube.com/watch?v=ZvCI-gNK_y4 theme music] from the 1975 film ''{{w|Jaws (film)|Jaws}}'', which has come to represent impending danger.

9603120071 was an actual accession number for an [https://adamswebsearch2.nrc.gov/webSearch2/main.jsp?AccessionNumber=9603120071 incident] at San Onofre Nuclear Generating Station in which four slightly contaminated stray kittens were found, cleaned, and adopted. No clock times were mentioned in the report.

Real-world nuclear power stations have strictly regulated control rooms which would prevent the simultaneous presence of fireworks, juggling and birthday celebrations.{{Citation needed}}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Facility: East Valley Nuclear Plant
:Date: 12/10/2021
:Report ID: 9603120071
:Event description: Roughly '''18 hours''' prior to the incident, an Amazon package containing fireworks was mistakenly delivered to the reactor control room and left under the console.
:The next day, at approximately '''14:00''', technician A arrived at the facility with a bag containing four juggling pins. At '''14:20''', technician A entered the control room, and joined technician B at the console.
:At '''14:28''', technician C exited the elevator and approached the control room holding a birthday cake intended for technician B.
:At '''14:29:22''', technician A said "Hey [technician B], check out this cool trick I learned" while taking out the juggling pins. Technician B turned to look just as, at '''14:29:26''', technician C entered holding the cake.

:[Caption below the panel]:
:You know things are about to get bad when the incident report starts including seconds in the timestamps.

{{comic discussion}}

2553: Incident Report

2021-12-10T22:20:26Z

172.70.135.98:

2552: The Last Molecule

2021-12-09T04:40:32Z

172.70.135.98:

{{comic
| number = 2552
| date = December 8, 2021
| title = The Last Molecule
| image = the_last_molecule.png
| titletext = Biology is really struggling; they're barely at 93% and they keep finding more ants.
}}

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

There are an infinite number of ways to arrange atoms into molecules, and chemistry is the study of the interaction of subatomic particles, atoms, and molecules, not simply the cataloging of all specimens of molecule.

This is reminiscent of biology's focus on previous centuries on simply cataloging the species on Earth.

Further, the goal of science is not to "complete" a field, but to understand it better and better. No scientific field, with the possible exception of optics, is considered fully understood.

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

2552: The Last Molecule

2021-12-09T04:37:24Z

172.70.135.98: /* Explanation */

{{comic
| number = 2552
| date = December 8, 2021
| title = The Last Molecule
| image = the_last_molecule.png
| titletext = Biology is really struggling; they're barely at 93% and they keep finding more ants.
}}

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

There are an infinite number of ways to arrange atoms into molecules, and chemistry is the study of the interaction of subatomic particles, atoms, and molecules, not simply the cataloging of all specimens of molecule.

This is reminiscent of biology's focus on previous centuries on simply cataloging the species on Earth.

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