explain xkcd - User contributions [en]

Talk:2201: Foucault Pendulum

2019-09-12T09:17:27Z

108.162.229.48:

I take it the pendulum is somewhere deep underground, which would shield Black Hat from the cataclysmic side effects?
Besides, they have several backup pendulums that while not enough to maintain rotation are sufficient to slow the half enough to preserve life.[[Special:Contributions/108.162.212.149|108.162.212.149]] 20:11, 11 September 2019 (UTC)

If the pendulum could really affect Earth's rotation, Black Hat wouldn't need to stop the pendulum entirely; he'd only need to prevent its plane of oscillation from rotating. Another thought: if the pendulum and Earth's rotation were really bidirectionally linked somehow, there would probably be nothing Black Hat could do to alter the pendulum's plane of oscillation -- any more than he could alter the rotation of the Earth with just one human being's strength. That last thought doesn't seem to be the case within this story, though, or else the final frame's news report wouldn't have happened. [[User:Trueflint|Trueflint]] ([[User talk:Trueflint|talk]]) 20:46, 11 September 2019 (UTC)
:Who says it's the energy from Black Hat's grab specifically? Maybe the magic pendulum just tells a device in the Earth whether or not the planet should be spinning, based on the current state of the pendulum. [[Special:Contributions/172.68.46.167|172.68.46.167]] 08:15, 12 September 2019 (UTC)

Why does the description description Megan as a "professor?" She could just as easily be a teacher, a docent, a scientifically-interested parent, or just a random bystander. 11 September 2019

The sentence "It stays in a fixed plane while the Earth rotates under it." and the correspoding text in explanation are wrong. It would be true only if the pendulum was located on one of Earth's poles. Elsewhere, the plane in which the pendulum moves would still rotate with respect to its surrondings, but slower than on the pole. The rotation speed is proportional to the sine of latitude. At the equator, the plane would stay fixed with respect to its surroundings. See [https://en.wikipedia.org/wiki/Foucault_pendulum#Explanation_of_mechanics Wikipedia].--[[Special:Contributions/162.158.93.207|162.158.93.207]] 23:45, 11 September 2019 (UTC)
:As a Physics teacher, I strongly support this. The fact that a Foucault's pendulum is keeping its oscillation plane constant with respect to an absolute reference frame is a common misconception, it should be mentionned as frequently as possible.--[[Special:Contributions/108.162.229.48|108.162.229.48]] 09:17, 12 September 2019 (UTC)

The Foucault Pendulum in this comic strongly resembles the one in the Franklin Institute in Philadelphia (both in shape and the way it is knocking over the pegs). Perhaps this should also be noted in the trivia section?[[Special:Contributions/162.158.126.46|162.158.126.46]] 05:16, 12 September 2019 (UTC)

2199: Cryptic Wifi Networks

2019-09-07T16:51:49Z

108.162.229.48: /* Explanation */

{{comic
| number = 2199
| date = September 6, 2019
| title = Cryptic Wifi Networks
| image = cryptic_wifi_networks.png
| titletext = They actually showed up on the first scan by the first WiFi-capable device.
}}

==Explanation==
{{incomplete|Created by a Toshiba-U2187-OfficeLink-Net46UHZ. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

In the comic, a character with a knit cap is on top of a high mountain in a remote location. He sees a Wifi network name listed on his handheld device, perhaps a cellular telephone. Cryptic {{w|Wi-Fi}} (or Wifi) network names, called SSIDs, are the source of a joke about not knowing where the corresponding {{w|wireless router}} is located, suggesting they are unexplained phenomenon of some sort instead of wireless radio devices. Some of the earliest Wifi devices like printers and {{w|internet}} routers advertised cryptic SSIDs, as do many of them today. In 1998, {{w|Lucent}} introduced the [https://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Wavelan-IEEE.html WaveLAN IEEE], the first {{w|integrated circuit}} chip set supporting the IEEE 802.11 wireless {{w|LAN}} protocol, spinning off {{w|Agere Systems}} to produce them in 2000. Wifi followed mid-1990s short-range wireless networks like {{w|Bluetooth}} and radio internet protocols like the 1980s {{w|KA9Q}}, with roots going back to the earliest {{w|ticker tape}} digital telegraphy systems from the mid-1850s. [https://techtalk.gfi.com/the-31-funniest-ssids-ive-ever-seen/ Humorous SSID names] are not uncommon.

The name of the network displayed, called its {{w|Service set (802.11 network)|SSID, which stands for "service set,"}} is '''Toshiba-U2187-OfficeLink-Net46UHZ''' which is 33 characters long, unfortunately one character more than are allowed. {{w|Toshiba}} is a multinational electronics conglomerate manufacturing many products including untold multitudes of different kinds of printers over the years. Such devices often have embedded {{w|wireless access point|wireless access points}} including the manufacturer name in the SSID. Many network names contain words like Net, Office or Link. The code might indicate a model U2178 device from Toshiba named (or having an interface program named) OfficeLink, which has a sub-model number or operates on a wireless network designated 46UHZ. That "Hz" is an abbreviation for {{w|Hertz}} suggests that designation may or may not have something to do with the frequency on which the transmitting device operates. Or U2178 could be a serial number for a user or a utility pole. We don't know whether the SSID is connected to a network of more than one or is just one device. While the most likely explanation might be a printer plugged in somewhere nearby, other possibilities include a television, cryptocurrency mining rig, speaker, pacemaker, alarm system, fashion accessory, autonomous antimissile defense system node, hobby project, surveillance device, {{w|Loon LLC|balloon}}, distributed denial of service attack platform malware-infested coffee pot, {{w|Starlink (satellite constellation)|satellite}}, vending machine, telecommunication facilities, {{w|Facebook Aquila|solar-powered drone}}, distributed exoskeleton, visiting interstellar civilization, power-to-gas pipeline valve, [http://www.geekculture.com/joyoftech/joyarchives/2340.html ransomware worm nest,] or anything else in the Wifi {{w|Internet of Things}}. Sometimes, the {{w|ionosphere}} reflects radio waves, vastly increasing the distance that they can travel to and from remote locations. The padlock icon indicates that a password is required to communicate. The "join other network" option allows for manually typing SSIDs to attempt to connect with networks which are not configured to display their SSIDs.

Network names can be used to track the geographic locations of mobile devices, for example in the {{w|Wi-Fi positioning system}}. Google {{w|street view}} equipment records locations of networks to assist with {{w|geolocation}}. Location information can be searched in tools like [https://wigle.net/ Wigle] or [https://openwifimap.net/ OpenWifiMap]. The {{w|Institute of Electrical and Electronics Engineers}} (IEEE) committee number for Wifi is {{w|IEEE 802.11|802.11}} which is composed of sub-committees like {{w|IEEE 802.11ad|802.11ad}}, designing the 60 GHz Multiple Gigabit Wireless System (MGWS) and {{w|IEEE 802.11ay|802.11ay}} working on {{w|MIMO|multiple input, multiple output}} (MIMO) bandwidth enhancements. The {{w|List of router firmware projects|software which produces SSID listings}} is administered by {{w|List of wireless community networks by region|network communities}} and depends on {{w|Wireless mesh network|mesh configurations}}. Alternatives include [https://news.ycombinator.com/item?id=20861948 bluetooth mesh networks] and other {{w|wireless ad hoc network|''ad hoc'' networks}} to provide internet connectivity services.

The title text indicates that the first Wifi networking client interface displayed unexpected SSIDs. If true, this could potentially rule out all of the alternative explanations other than an alien visitation, a software bug, time travel, trans-multiverse or trans-dimensional communication, hardware misconfiguration, or the supernatural. (It is worth noting that cryptic-sounding wi-fi networks actually being generated by a time-traveling alien entity as a trap was used as a plot device in the 2013 ''Doctor Who'' episode ''The Bells of Saint John''.)

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

:[A human with a knit cap and a backpack is checking his phone at the highest mountain in a mountainous landscape.]

:Phone: Available WiFi Networks
:Phone: Toshiba-U2187-OfficeLink-Net46UHZ
:Phone: [in gray] Join other network

:[Caption below the comic:]
:Tech Trivia: No one actually knows what devices produce those cryptic WiFi networks. They just appear at random across the Earth's surface.

{{comic discussion}}

Talk:665: Prudence

2015-05-16T16:47:36Z

108.162.229.48:

Anyone else reminded of the MALP from Stargate? Portal to another world, the probe is similar in design, etc [[Special:Contributions/141.101.99.228|141.101.99.228]] 19:14, 25 December 2013 (UTC)
:Exactly what I thought [[Special:Contributions/108.162.229.48|108.162.229.48]] 16:47, 16 May 2015 (UTC)

908: The Cloud

2014-02-13T17:16:22Z

108.162.229.48: Removed extra "the"

{{comic
| number = 908
| date = June 6, 2011
| title = The Cloud
| image = the cloud.png
| titletext = There's planned downtime every night when we turn on the Roomba and it runs over the cord.
}}

==Explanation==
This comic is a reference to all of the companies that rolled out "cloud" services like {{w|Google}}'s and {{w|Amazon}}'s music service and {{w|Apple}}'s aptly named {{w|iCloud}} online backup service around the time that the comic was released.

Also, in this comic is a reference to {{w|caching}} and the {{w|Roomba}}. Caching is the way that remote sites would locally store data from "The Cloud" to prevent from putting too much pressure on Black Hat's non-Enterprise class cable modem. The Roomba is a round vacuum that runs automatically around the house. The Roomba begins to learn the dimensions of rooms, however, apparently it has never learned not to run over the cord.

The regular nightly downtime is a reference to an [http://www.snopes.com/horrors/freakish/cleaner.asp urban legend] in which some critical piece of equipment (often a server) is unplugged regularly so that a vacuum cleaner or similar janitorial tool can be temporarily plugged in. Although the Roomba vacuum does not require this computer's outlet, "running over the cord" apparently causes similar interruption in service.

This comic is reminiscent of the British sitcom "The IT Crowd" in which they showcase a box that they make the rest of their non-Tech coworkers believe is "The Internet".

The last panel showcases both Black Hat's stereotypical sadism and callousness. When Cueball asks about the hazard (namely, tripping) implicit in a cord stretching across a room, Black Hat responds by implying no one would want to do that, because it's unpleasant. Cueball responds with the fact that some people do things by accident, to which Black Hat says he doesn't know anyone like that. The only way Cueball can disprove this (at least quickly) is by admitting he's one of those people, opening him up to Black Hat's ridicule.

==Transcript==
:[Cueball finds a computer tower with a wire leading away from it.]
:Cueball: What's this?
:Off-screen: The Cloud.

:[Cueball looks behind him. The wire leads to an outlet in the wall next to where Black Hat sits at a desk with a computer. Another wire leads from that outlet to Black Hat's computer.]
:Cueball: Huh? I always thought "The Cloud" was a huge, amorphous network of servers somewhere.
:Black Hat: Yeah, but everyone buys server time from everyone else. In the end, they're all getting it here.

:[A close-up of Black Hat.]
:Cueball: How? You're on a ''cable'' modem.
:Black Hat: There's a lot of caching.

:[A close-up of Cueball, looking down at the tower at his feet.]
:Cueball: Should the cord be stretched across the room like this?
:Black Hat: Of course. It has to reach the server, and the server is over there.

:[Cueball turns back to the Black Hat, still sitting at the computer.]
:Cueball: What if someone trips on it?
:Black Hat: Who would want to do that? It sounds unpleasant.
:Cueball: Uh. Sometimes people do stuff by accident.
:Black Hat: I don't think I know anybody like that.

{{comic discussion}}
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Cueball]]