explain xkcd - User contributions [en]

Talk:2014: JWST Delays

2021-12-22T04:51:11Z

108.162.210.219: One hopefully last delay.

Haha - I made this same graph 2 weeks ago! [[User:Cosmogoblin|Cosmogoblin]] ([[User talk:Cosmogoblin|talk]]) 17:39, 2 July 2018 (UTC)

Suggest the last sentence be made more general: "The title text refers to a fundamental question of the Big Bang Theory; will the universe expand forever, or will is collapse back on itself? The likely answer to this question has changed over the decades as new measurements have been made, and new theories such as dark matter and dark energy developed to explain the new measurements. Apparently, and for an analogous reason, between 2018 and 2020 the likely answer to the fundamental JWST question will change." [[User:GODZILLA|GODZILLA]] ([[User talk:GODZILLA|talk]]) 17:58, 2 July 2018 (UTC)
:I agree to the current sentence saying "and compares the universe’s accelerating expansion to the apparently ever-delaying schedule" but were the hell comes the conclusion that "the JWST will have enough delays to fill a universe"? This does not make any sense. [[User:Elektrizikekswerk|Elektrizikekswerk]] ([[User talk:Elektrizikekswerk|talk]]) 07:59, 3 July 2018 (UTC)

Does today's prediction of 2026 count? If that is included in the data set, it would then skew the best-fit line to be steeper. If a new prediction is made using that new best-fit line, that would further skew the line, and so on, causing the acceleration the title text anticipates between 2018 and 2020.[[Special:Contributions/162.158.63.88|162.158.63.88]] 20:10, 2 July 2018 (UTC)

> Until the slope of the line becomes more than one and the prediction goes to the past, right? [[Special:Contributions/108.162.216.16|108.162.216.16]] 21:55, 2 July 2018 (UTC)

:No, it doesn't count, because it's just '''prediction''', while the data set is of (official) '''planned launch dates'''. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 22:06, 2 July 2018 (UTC)

:The Wikipedia data (taking the midpoint for ranges) fits a linear function with slope 0.660618 and intercept 687.739. This implies convergence at 2026.45, which is why Randall is predicting late 2026 for the actual launch. [[Special:Contributions/172.69.22.56|172.69.22.56]] 15:04, 10 July 2018 (UTC)

[[wikipedia:Heinz von Foerster#Doomsday equation|Von Foersters's doomsday]] is Friday 13th of November 2026. (cue Twilight Zone intro) [[Special:Contributions/162.158.89.175|162.158.89.175]] 21:20, 2 July 2018 (UTC)

Why does he keep saying it's 2021? Is he trying to skip Trump's term or what? --[[Special:Contributions/172.68.211.10|172.68.211.10]] 00:30, 3 July 2018 (UTC)
Why do you think that Trump will get only 1 term?[[Special:Contributions/141.101.76.70|141.101.76.70]] 17:10, 3 July 2018 (UTC)

This is the same chart for the new airport in Berlin. Sadly its slope is not less than one, it is indeed accelerating... 
2006     2011 
2010     2012 
2012     2013 
2013     2014 
2014     2016 
2015     2018 
2016     2018 
2017     2022 
[[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 07:57, 3 July 2018 (UTC)
:[https://de.wikipedia.org/wiki/Bau_des_Flughafens_Berlin_Brandenburg#cite_ref-136] says that the planned launch date from December 2017 is in October 2020 (not 2022). That would make the slope slightly less than 1 (unless you ignore the 2016->2011 data point, as outlier) --[[Special:Contributions/162.158.91.35|162.158.91.35]] 09:27, 4 July 2018 (UTC)
::There was a 2022 prediction earlier in 2017, I took the maximum value for each year. And honestly, 2202 sounds more reasonable than 2020 for me. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 14:39, 4 July 2018 (UTC)

I feel a quadratic regression would be needed to determine acceleration / deceleration [[Special:Contributions/172.68.59.24|172.68.59.24]] 13:54, 3 July 2018 (UTC)

: If you plot out the least-squares fit as it changes over time (i.e. repeat Randall's graph as each new data point was added), it fits a quadratic quite well. And converges to a 2025 date.

I wonder what this chart would look like for new york's 2nd avenue subway.
[[Special:Contributions/162.158.75.130|162.158.75.130]] 17:36, 3 July 2018 (UTC)

At least there _is_ a slope. How about Trump's wall? [[Special:Contributions/173.245.52.151|173.245.52.151]] 00:52, 4 July 2018 (UTC)

Two more lines are coming together... the year and the XKCD index. 2018 should happen next week. [[User:IonFreeman|IonFreeman]] ([[User talk:IonFreeman|talk]]) 14:22, 5 July 2018 (UTC)

The last three data points have a slope greater than one. Just sayin'. [[User:Redbelly98|Redbelly98]] ([[User talk:Redbelly98|talk]]) 19:55, 29 July 2018 (UTC)

:"NASA announced that the launch date has once again been delayed to 31 October 2021." THE RIDE NEVER ENDS [[Special:Contributions/108.162.215.188|108.162.215.188]] 05:24, 17 September 2020 (UTC)

::November to December 2021 now... amazing. [[Special:Contributions/172.69.35.65|172.69.35.65]] 20:24, 21 June 2021 (UTC)

== November 2021 ==

Is [https://www.space.com/james-webb-space-telescope-launch-delay-november-2021] on track for the extrapolation shown? [[Special:Contributions/172.69.35.115|172.69.35.115]] 18:31, 24 June 2021 (UTC)

== Update from 2021 ==
Turns out the last update in the comic seems to have been correct. As of Sept '21, it's still due to go up in Nov. '21.
https://www.jwst.nasa.gov/content/about/launch.html
https://www.nasa.gov/press-release/nasa-announces-new-james-webb-space-telescope-target-launch-date

[https://i.imgur.com/BssUkbG.png '''Updated Image''']. I've added the blue dots to represent the updated launch dates. (Still in 2021) [[Special:Contributions/172.69.48.147|172.69.48.147]] 20:43, 31 August 2021 (UTC)

On September 8, ESA has announced December 18, 2021, as the planned launch date.[https://www.esa.int/Science_Exploration/Space_Science/Webb/Targeted_launch_date_for_Webb_18_December_2021] 2021 remains possible, but if there are further delays (and launches like this are delayed frequently), we may indeed slip into 2022. [[Special:Contributions/162.158.92.245|162.158.92.245]] 05:55, 9 September 2021 (UTC)

The launch readiness date is moving to no earlier than Dec. 22 because they [https://blogs.nasa.gov/webb/2021/11/22/nasa-provides-update-on-webb-telescope-launch/ '''almost dropped it''']
[[Special:Contributions/141.101.76.223|141.101.76.223]] 09:02, 23 November 2021 (UTC)

I find it interesting that in [https://www.explainxkcd.com/wiki/index.php/2550:_Webb Comic #2550], posted 3 December 2021, Mr. Munroe returns to the topic of the Webb with a gag involving a particular launch date. This suggests to me that he has confidence the launch is indeed drawing nearer.
[[Special:Contributions/172.70.126.221|172.70.126.221]] 08:08, 5 December 2021 (UTC)

: Actually, I think that the December 2021 launch date is good. The vehicle is complete and the Ariane 5 is ready. (Edit: i forgot to sign my post) --[[Special:Contributions/162.158.62.120|162.158.62.120]] 02:31, 6 December 2021 (UTC)

Delayed to [https://www.space.com/james-webb-space-telescope-launch-delay-december-24 Christmas eve] now due to comms issue between satellite and rocket --[[Special:Contributions/172.70.162.77|172.70.162.77]] 15:50, 15 December 2021 (UTC)

And now it's [https://spacenews.com/jwst-launch-rescheduled-for-dec-24/ Christmas Day], due to weather. [[Special:Contributions/108.162.210.219|108.162.210.219]] 04:51, 22 December 2021 (UTC)

1105: License Plate

2016-09-17T04:59:59Z

108.162.210.219: /* Explanation */

{{comic
| number = 1105
| date = September 7, 2012
| title = License Plate
| image = license_plate.png
| titletext = The next day: 'What? Six bank robberies!? But I just vandalized the library!' 'Nice try. They saw your plate with all the 1's and I's.' 'That's impossible! I've been with my car the whole ti-- ... wait. Ok, wow, that was clever of her.'
}}

==Explanation==
[[Cueball]] has obtained a new {{w|Vehicle registration plate|license plate}}. The license plate number one receives is often the next in sequence, available at the time and place of registration. However, in many localities, for an additional fee one can select his or her own "personalized" license plate number (called a {{w|vanity plate}}), subject to certain criteria, and availability.

In this comic, Cueball has elected to purchase the personalized license plate number "1I1-III1" or "one, letter I, one, dash, letter I, letter I, letter I and one". He believes the ambiguity between the letter I and the digit 1 on the plate will make it very difficult for anyone to correctly identify his vehicle if he commits a crime. Some localities have more distinct "1" and "I" characters in their license plate font than others, but often when a crime is committed witnesses only has a short time to look at the plate, and will then be confused.

In principle his idea did work, cause when the police end up interviewing a witness of a crime scene in the end of the comic, he can only say that it ''The thief's license plate was all "1"s or something''. What Cueball does not count on is that there are no other license plates made up entirely of the letter I and the digit 1. Thus, when witnesses report a vehicle with a license plate of either/or I's and 1's, the police know exactly who the perpetrator is.

Given the fact that the police still haven't caught him even though they have his address written on a {{w|Post-it note}} in their car, it seems like they had already though of the same idea, and when Cueball registered such a license plate they put up the address in the police cars, as they expected him to begin committing crimes. He may already have committed more than one, but they would soon stop him before it turned into a crime spree.

[http://imgur.com/jaiblHk Someone in New Hampshire appears to have done this in real life.]

The title text appears to be a conversation between Cueball and the police the next day when they show up at his address. It turns out that the the police suspect Cueball of six bank robberies. Cueball responds that "all" he did was vandalize the library. But the police disregards this as a ''nice try'' to avoid being arrested because witnesses saw a his license plate with all 1's and I's was used. Cueball does not understand this because he was with his car the entire time since he got the license plate. And just as he says this, he has an epiphany and states ''wait. OK, wow that was clever of her''. It is thus clear that he suspects that [[Megan]] have made a false license plate also with only a combination of I's and 1's. And then she has robbed six banks knowing that the police would be sure to suspect Cueball, who was so foolish to show his criminal intent by registering such a plate in the first place.

Knowing that the police will assume the car is his she has thus {{w|frameup|framed}} him. Hopefully for Cueball he can prove he was not involved in the robberies, but the polices certainty that they knew who the stupid guy was that committed the crimes, they may not have taken so much care in collecting evidence the first day of the crimes, and this will have given Megan time to run away with all the money, as no one was looking for her. So she may well have left the country with no one looking for a woman. This will make it more difficult for Cueball to avoid the blame.

It is clear that Megan would not be so stupid as to register another plate, because then they would know that there could be more than one criminal person. Also she would not have had time to get it, if the crime spree began soon after Cueball showed the plate to her. But if the fake plate makes people tell about the 1s and Is then the police would not ask further and maybe discover that the plate might have looked fake.

Note the yellow police line seems to say ''Police strip do not cross'', where ''Police line do not cross'' seems to be the only sentence used normally (unless it is ''crime scene do not cross'', but that also does not fit).(Of course, this could be a pun about the fact that this occurance is a comic ''strip''.)

==Transcript==
:[Cueball is walking in from the right holding a license plate up with both hands for an off-panel Megan to see. It is possible to see the plate, but here it looks like all I's (or 1's).]
:Cueball: Check out my personalized license plate!
:Megan (off-panel): <nowiki>"1I1-III1"?</nowiki>
:Cueball: It's perfect!
:Plate: III-IIII

:[In this frame-less panel Megan is sitting in an office chair holding and looking at the plate while Cueball stand next to her rubbing his hands together in front of him.]
:Cueball: No one will be able to correctly record my plate number!
:Cueball: I can commit any crime I want!
:Megan: Sounds foolproof.

:[A man with hair only around his neg and glasses holds out a hand towards a bald male police officer with a black peaked cap with white emblem on the front. The police man interviews their witness holding a notepad and a pen. Another likewise caped female officer is Ponytail who walks to the left arm pointing left. There is a line of yellow police tape behind them with text partially obscured by the characters. At the top left of the panel there is a small frame with a caption:]
:Soon:
:Witness: The thief's license plate was all "1"s or something.
:Police officer: Oh. ''That'' guy.
:Ponytail: His address is on a post-it in the squad car.
:Yellow strip (text not visible in brackets): Poli(ce strip) do not cross (poli)ce stri(p do not) cross.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]

1028: Communication

2016-09-17T04:48:43Z

108.162.210.219:

{{comic
| number = 1028
| date = March 12, 2012
| title = Communication
| image = communication.png
| titletext = Anyone who says that they're great at communicating but 'people are bad at listening' is confused about how communication works.
}}

==Explanation==
This comic is divided into two parts, the first two rows of panels and then the third one.

The first part demonstrates a failed attempt at communication:

*[[White Hat]] notices a dangerous hole, and thinks he should warn people about it.
**The symbol of the triangle with the exclamation mark in it is widely used on {{w|warning sign}} and it means "{{w|Warning_sign#General_caution|General caution}}".
*White Hat encounters [[Hairy]] and tries to warn him about the hole, while Hairy is wondering what White Hat is pointing at not understanding what he says.
*Hairy doesn't understand the warning, he continues to think without speaking. Now he thinks of a frustrated White Hat.
*Hairy continues to only think of what he can see, and now this is the fact that White Hat is leaving. As White Hat leaves he is thinking about Hairy's lack of understanding and about his silence.
*White Hat encounters [[Megan]] and is now so annoyed about Hairy that he rather talks about his lack of communication than about the dangerous hole. Megan on the other hand tries to tell White Hat about another dangerous hole if he continues to walk along.
*White Hat and Megan pass each other. White Hat now thinks about both the silent Hairy and the talking Megan who both failed to understand him. Megan is just frustrated by the outcome of her encounter and thinks about White Hat talking.
*Megan then meets Hairy while they are both still thinking about White Hat
*They now share their common experience of seeing White Hat. Finally Hairy talks.
*They both continue towards the first hole, unaware of it, talking about White Hat. (Hairy is drawn without hair both here and in the next panel - see [[#Trivia|Trivia]] below.)
*Megan and Hairy fall into the first hole since it wasn't properly communicated to them.
*White Hat falls into the second hole since it wasn't properly communicated to him.

The holes in the sidewalk are fairly deep, about one person deep; unaware and careless people don't notice them when they come upon them, which makes them symbolic of any problem or danger one can encounter in life, and could avoid if properly warned or careful.

The second part demonstrates a much more successful attempt at communication:

*[[Beret Guy]] notices a dangerous hole, and thinks he should warn people about it.
*He even runs out of the picture to warn people (as can be interpreted by the fact that he has reached further in the next panel than White Hat).
*Beret Guy finds [[Cueball]], and tells him to come along. Cueball only sees Beret Guy stretching out his hand.
*Beret Guy takes Cueball's hand and leads him towards the hole. Cueball doesn't understand why (as shown by the question marks in his thought bubble surrounding his thought of Beret Guy), but follows Beret Guy anyway.
*Beret Guy leads Cueball to the hole and points it out for him.
*Finally both Beret Guy and Cueball leave the hole thinking about the danger of it. Beret Guy has managed to properly warn Cueball about the hole.

It is very typical for the character Beret Guy to succeed, especially with something difficult, where White Hat fails.

The title text references the requirement that "communication" is a two-sided process, and just because you think you have made your point clear this does not mean that you have "communicated" the information to them: if they failed to understand, then it may as well mean that ''you'' failed to communicate, and not necessarily that ''they'' are bad at listening. And if you always encounter this, then it is you who are confused about how communication works

==Transcript==
:[White Hat looks down at a large gap in the walkway; a thought bubble with a warning symbol and an image of the gap appears above his head.]

:[White Hat walks to the right, away from the gap, and encounters Hairy, to which he speaks (in iconographic speech bubble form) while pointing toward the gap, attempting to inform him about the gap. A thought bubble appears above Hairy's head with an image of White Hat pointing.]

:[White Hat continues, waving his arms, still talking about the gap. Hairy's thought bubble continues to contain images of White Hat, now gesturing frantically.]

:[Hairy shrugs in a nonplussed manner, and White Hat leaves off the right side of the frame. Both have thought bubbles displaying the other's reaction.]

:[White Hat continues to the right and comes across Megan. He tells her about the reaction of Hairy (still all in iconographic form); she simultaneously tries to tell him about a gap and gestures off to the right of the frame.]

:[White Hat and Megan both leave the frame. Megan exits left thinking of White Hats reactions; White Hat exits to the right while thinking about both Hairy and Megan's reactions.]

:[Megan (still thinking about White Hat) encounters Hairy (who is also still thinking about White Hat).]

:[Megan and Hairy talk about White Hat.]

:[Megan and Hairy (now without his hair) continue talking about White Hat as they exit the frame to the left.]

:[A commotion is heard from the left.]
:Explosion to the right: !!! ** !!

:[Megan and Hairy (still without his hair) have fallen into the gap in the walkway. A commotion is then also heard from the right.]
:Explosion to the right: !!! ** *

:[White Hat has fallen into another gap.]

:[Beret Guy looks down at a large gap in the walkway; a thought bubble with a warning symbol and an image of the gap appears above his head.]

:[Beret Guy runs off the frame to the right.]

:[Beret Guy meets Cueball and reaches out to him. He tells him (still in iconographic form) that Cueball should take Beret Guys hand. Cueball has a thought bubble of Beret Guy with his arm stretched out.]

:[Beret Guy takes Cueball's hand and leads him along to the left. Cueball's thought bubble has two question marks around Beret Guy.]
:Cueball: ? ?

:[Beret Guy leads Cueball to the gap and points it out to him.]

:[Beret Guy and Cueball walk away from the gap to the right, now both thinking about the gap with a warning symbol above it.]

==Trivia==
*[[Randall]] made a mistake in this comic:
**Hairy seems to "lose" his hair in the last two frames he is in with Megan, but it's still the same person.
**The Cueball that appears in the last four frames is not Hairy without hair.
**This is clearly evidenced by Randall's [http://xkcd.com/1028/info.0.json transcript of the comic].

{{comic discussion}}
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Cueball]]

Talk:379: Forgetting

2015-11-05T10:02:05Z

108.162.210.219:

The syntax for pointers in C++ is ''&pointer'' and ''*pointer''. The arrow syntax is used e.g. in PHP. So this explain does need a review. And furthermore it should focus on the assert joke, understandable for non programmers.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 18:48, 31 July 2013 (UTC)
:Actually this works in C++ too. (*pointer).property is the same as pointer->property -- 17:58, 31 july 2013 (Time in Florida)
::Do you have a code snippet, maybe this could help me to explain this comic for non programmers.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 22:43, 31 July 2013 (UTC)
:::At the moment I don't have a computer, just my phone, but I'll try (so i appologize for any typos in advance, you may correct them)
pair<int, int>* pntr = make_pair(5, 8);
cout << (*pntr).first << endl;
cout << pntr->first << endl; // the same as above
-- 22:12, 31 July 2013 (Florida)
:I removed PHP as a possible language since PHP variable names start with a $. Zetfr 09:24, 20 May 2015 (UTC)
::IT IS A COMBINACION EN C++/ANOTHER LENGUAGE IN THE FOURTH PANEL ASSERT HAS NOT PARENTHESES. IN C++ THE ASSERT MUST HAVE THE PARENTHESES AND SO CANNOT BE A C++ PROGRAM. PLEASE ADVISE