explain xkcd - User contributions [en]

Talk:2289: Scenario 4

2020-04-05T22:03:11Z

172.69.250.58:

Should definitely make a note re: this officially-Friday comic releasing late Saturday afternoon (EDT). [[User:TPS|TPS]] ([[User talk:TPS|talk]]) 22:06, 4 April 2020 (UTC)
Or is this actually the april fool comic, except it fooled us by being on a Saturday? [[Special:Contributions/162.158.74.81|162.158.74.81]] 22:12, 4 April 2020 (UTC) Sam
Perhaps more likely because the actual April Fool's comic (due Wednesday) delayed 'til Friday. [[User:TPS|TPS]] ([[User talk:TPS|talk]]) 22:19, 4 April 2020 (UTC)

The title should probably be changed, the xkcd site uses the numeral "4" whereas we're using the word "four."--[[User:GoldNinja|GoldNinja]] ([[User talk:GoldNinja|talk]]) 22:50, 4 April 2020 (UTC)
I accidentaly originally put it under Sequence Four. It shows in the image name.

I hope I fixed it correctly [[User:Bugstomper|Bugstomper]] ([[User talk:Bugstomper|talk]]) 02:17, 5 April 2020 (UTC)

Another instance of a graph with poor labels ("bad stuff"), even without the time travel. [[Special:Contributions/162.158.158.225|162.158.158.225]] 23:54, 4 April 2020 (UTC)

The issue of time-traveling COVID-19 problems has already be considered in Onion Public Radio's The Topical. https://www.youtube.com/watch?v=E3GQwOcsChQ Apologies for any poor rule-following as this is my first edit. [[User:RandomEdditMemory|RandomEdditMemory]] ([[User talk:RandomEdditMemory|talk]]) 00:00, 5 April 2020 (UTC)RandomEditMemory

The time travel in this comic is probably a reference to the time offset resulting from the April Fool's comic, but possibly coincidentally the comic showed up here in New Zealand in the morning of the April 5 change to Standard Time when the clocks did turn back an hour. [[User:Bugstomper|Bugstomper]] ([[User talk:Bugstomper|talk]]) 01:55, 5 April 2020 (UTC)
: The time travel is almost certainly not a deliberate reference to the April Fool's comic being late (or to any implementation of DST). Rather, there's 4 graphs, each with an increasingly higher curve. the first tapers off, appearing to be approaching an asymptote, with an ever-decreasing rate of increase -- or even heading to a decrease. The second has a steeper slope for a while, but then does start to taper off. whether it becomes linear, approaches an asymptote, or starts declining off the edge of the graph is not known. The third scenario appears to be an exponential curve. The 3.5 scenario (not shown) would be to have a vertical asymptote, where "bad stuff" shoots off toward infinity as time approaches T. Then the only other thing left to do with a curve is to have it continue back the way it came. Been too long since I was in that level of math, but I'm pretty sure it's problematic if you Y-axis has two values at a point on the X-axis. This isn't showing two different functions converging as time progresses, but rather that a high values of "bad stuff," time goes backward.

From the explanation: "This is another comic in the coronavirus series." But ... is it? It certainly isn't explicitly so. The implicit argument is easy to make, but the fact that it is just "bad stuff" as a function of "time," it could easily be relevant to any number of bad scenarios: velociraptor attacks, Macarena flash mobs, mobile game IAP monetization, nationalistic views in politics, cat-based cheeseburger memes, or so on. It's not much of a stretch to say that the comic is topical to current events (especially given that there are many others in a sequence of implicitly or explicitly CoViD-related comics), but it still is a stretch to _definitely_ say so absent Mr. Munroe actually acknowledging so elsewhere, and then a citation would be needed, right?
:It definitely is. All those graphs (except the fourth, obviously) can be found in real countries' data. South Korea would be an example of scenario 1. The United States would be an example of scenario 3. The virus is on everybody's mind, so there's no way it's a coincidence. (I think labeling [[2283: Exa-Exabyte]] as a coronavirus comic is ''way'' more of a stretch.)

I suggest the mathematical background of the graph 'bending over backwards' should be explained in more detail because the contradiction between what is 'natural' tendency of the graph and what is possible mathematically is what makes for the core of the joke. I mean, let's imagine that the graph is a picture of some tangible object, as a non-mathematically inclined person might do. Let's say, it's a rope. Then after observing it 'bend upwards' more and more with each scenario that gets progressively 'worse', it would be reasonable to conclude that continuing to bend this object even more and 'overbending it' would naturally mean some kind of a catastrophe. In reality, of course, it is impossible just because of the way the graph is being plotted. Each next segment is added as time goes by and placed more to the right because the time is shown to flow right on the horizontal axis. Thus the only way this graph could bend like this is for the next added segment to be in time 'before' the last one. And since it is impossible to travel back in time (citation needed), such a graph is unlikely to be predicting a real scenario. --[[User:SomethingLike|SomethingLike]] ([[User talk:SomethingLike|talk]]) 06:30, 5 April 2020 (UTC)
:There are graphs, however, that have multiple Y-values for single X-values (graph of a square root function, at least for positive values of X, graphs of circles, or the batman equation. Might need an ELI5 why those are okay but the line curving back in time isn't.
To me this comic seems a commentary on alocalypse. Some see COVID-19 as the start of a coming apocalypse, and some worst apocalypse scenarios involve either an explosive AI researching things like time travel or ending our timeline as physics knows it, or all of us going back to survival mode on a landscape without any modern infrastructure. [[Special:Contributions/172.69.250.58|172.69.250.58]] 22:03, 5 April 2020 (UTC)

Talk:2280: 2010 and 2020

2020-03-13T23:17:44Z

172.69.250.58:

Please maintain your distance in these comments. No comments within 6 vertical inches of other comments, please. And any in-comment sneezing or coughing will result in your account being banned for a period of 3 weeks. [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 21:09, 13 March 2020 (UTC)

If the above information was new to you, please take this concise pamphlet. [[Special:Contributions/172.69.250.58|172.69.250.58]] 23:17, 13 March 2020 (UTC)

Talk:2280: 2010 and 2020

2020-03-13T23:17:23Z

172.69.250.58:

Talk:2280: 2010 and 2020

2020-03-13T23:17:03Z

172.69.250.58:

2201: Foucault Pendulum

2019-09-13T17:47:01Z

172.69.250.58: Removed random tangent that was mostly irrelevant to the article

{{comic
| number = 2201
| date = September 11, 2019
| title = Foucault Pendulum
| image = foucault_pendulum.png
| titletext = Trust me, you don't want to get on the wrong side of the paramilitary enforcement arm of the International Earth Rotation and Reference Systems Service.
}}

==Explanation==
{{incomplete|Created by the International Earth Rotation and Reference Systems Service. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
[[Black Hat]] is attending what appears to be a guided tour of a museum with a {{w|Foucault pendulum}}. [[Megan]] is explaining to him, [[Cueball]] and [[Ponytail]] about the device which demonstrates the rotation of the Earth.

Black Hat, being himself, immediately sees an opportunity to cause chaos and seizes it with both hands, quite literally - as he grabs the pendulum which causes the others to shout after him to stop. At first this would seemingly be for fear of ruining the delicate demonstration. However, in the final panel, the [[:Category:News anchor|news anchor]] [[Blondie]] reveals to us that by arresting the motion of the pendulum, Black Hat has somehow stopped the rotation of the Earth. However it was only briefly since the local {{w|Geophysicist}} managed to wrestle him down, and then it must be assumed they quickly restarted the pendulum and thus the Earths rotation.

This of course is blatantly impossible since the Foucault pendulum's motion is tied to the earth's rotation, not the other way around. That is except for this specific one, which does seem to control the Earths rotation. This must thus of course be located at one of the Earths poles, that is it must be the [http://www.southpolestation.com/trivia/00s/southpolefoucault.html one at the South Pole], as there is no place that stays fixed over the North Pole. Also it has to have been close to either pole, else no one would have been able to stop Black Hat afterwards and restart the pendulum. Because if the Earth suddenly stops rotation, then every loose object would continue with their normal rotation speed across, which would move them fast across the surface. Thus had this been at the Equator, no one would have been able to stop him afterwards, as everyone would have been killed instantaneously! See more below.

A Foucault pendulum is a regular {{w|pendulum}} that swings from a bearing that allows rotation in any direction, like your shoulder joint instead of your elbow. But has been set up to display the Earth is rotating beneath it. If the Earth were stationary, it would continue to swing over the same portion of the Earth as when it was released, but any pendulum will continue to swing in the same plane in space compared to the distant fix stars. So because the Earth moves beneath it (and in comparison to those distant stars), over the course of the day the pendulum's motion gradually changes direction relative to the room. The low-resistance bearing doesn't allow the rotation of the Earth to affect the motion of the pendulum, so it stays aligned to its original inertial reference frame according to the fix star (far away in space) rather than to the rotating surroundings which follow with the Earth's rotation. If the pendulum is at one of the poles, it will take a full day to move one full round. At the equator there is almost no movement, and in between it will take longer than 24 hours.

The fact that the Earth's rotation does not influence the motion of the pendulum does NOT mean that other things can't affect it - for example, by running up and manually repositioning the pendulum. Of course, the apparent rotation of the pendulum's plane relative to the Earth is an effect of the planet's motion, rather than the cause of it. Thus, stopping a Foucault pendulum manually does not entail pausing the rotation of the Earth.

[[Randall]] covered this scenario in detail in his [[what if?]] book, see [https://io9.gizmodo.com/xkcds-creator-explains-what-would-happen-if-earth-stopp-1625068208 XKCD's Creator Explains What Would Happen If Earth Stopped Spinning].

If it were somehow possible for a Foucault pendulum to control Earth's rotation (see above), Black Hat would probably not want to alter the momentum of the pendulum if he where not at one of the Earths poles. That is assuming he was told that it was related to Earth's rotation and assuming that he would prefer to preserve his own life over making chaos (unless due to his advanced technology, he can resist being slammed into a nearby wall at the speed of sound). The reason why is because if the rotation of Earth were to be stopped for even very short amounts of time (a few seconds), it would cause everything on Earth that wasn't bolted/fastened to the ground to move eastward compared to the now stationary ground. If they are near the Equator it would be at a speed of 300-360 meters per second, likely causing the death of most lifeforms on Earth beneath a certain latitude almost instantaneously. Those close enough to the poles may survive though. Also this will cause massive windstorms, tsunamis, volcanic and tectonic events on a scale not previously observed on Earth. This would likely cause a mass extinction event and wipe out 99% of humanity in the initial events (which would eventually lead to our extinction). It is possible that Black Hat's grabbing the pendulum would cause a gradual slowing prior to stopping, minimizing the issue (though this doesn't seem to be the case), but the results would still be catastrophic, as the aforementioned events are still likely to occur (specifically the tsunamis and volcanic events). However, as mentioned above, if this pendulum was located at the South pole, then Black Hat and other people around him would not be affected immediately, and he could both do it, survive and be stopped again. The question is if there would be any more news stories to cover this given what would happen to the rest of the world! If there was no-one to readjust the pendulum's rotation, then certain events would happen after the initial damage (see this video [https://www.youtube.com/watch?v=q_T7L8rt1Ec])

In the title test the [https://www.iers.org/IERS/EN/Home/home_node.html International Earth Rotation and Reference Systems Service] is mentioned. It is an organization providing standards for global time and reference frames; this organization would have a very rough day after the fiasco with Black Hat. The title text refers to a (probably) fictional paramilitary enforcement arm of this organization and the foolishness of tangling with such a force. If Foucault pendulums were somehow able to influence the rotation of the Earth in any measurable way, the IERS enforcers would probably strictly control their installation and monitor their use (and misuse). Black Hat is likely in for a rough day as well. It seems like some on this team are geophysicist since they where the one that took Black Hat down.

==Transcript==
:[Megan is addressing Cueball, Black Hat and Ponytail as they are looking a pendulum, which consist of a large swinging sphere with a spike beneath it hanging on a string coming down from above with seven small markers under it. Megan is pointing at it while it is swinging towards them, as indicated with lines behind the sphere and the string.]
:Megan: This Foucault pendulum demonstrates Earth's rotation. It stays in a fixed plane while the Earth rotates under it.

:[Close-up on Black Hat holding a hand to his chin.]
:Black Hat: Hmm, really.
:Black Hat: So that means...

:[Zoom out to Black Hat running to the pendulum grabbing it with both hands. He turns over two of the seven markers that can now been seen to be small pegs standing up on he floor beneath the pendulum. A line goes from his hand on the pendulum up to a sound bubble. Two people off-panel yell at him.]
:Character of panel 1: Hey!
:Character of panel 2: Stop him!
:Sound:''Grab''

:[Blondie as a news anchor uses her out-held hand to indicating Black Hat who is shown on a screen next to her. There is a caption in two line above it. The first line in normal text, the second line in white in a black rectangle. There are further unreadable text below the picture.]
:Blondie: The Earth's rotation was briefly halted today until geophysicists wrestled the intruder to the ground...
:Breaking
:''news''

{{comic discussion}}

[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Blondie]]
[[Category:News anchor]]
[[Category:Physics]]