explain xkcd - User contributions [en]

Talk:1895: Worrying Scientist Interviews

2017-09-27T14:49:43Z

DarkJMKnight: /* Heliologist */ new section

== Heliologist ==

Why not use Heliologist? :~) [[User:DarkJMKnight|DarkJMKnight]] ([[User talk:DarkJMKnight|talk]]) 14:49, 27 September 2017 (UTC)

1895: Worrying Scientist Interviews

2017-09-27T14:47:11Z

DarkJMKnight:

{{comic
| number = 1895
| date = September 27, 2017
| title = Worrying Scientist Interviews
| image = worrying_scientist_interviews.png
| titletext = They always try to explain that they're called 'solar physicists', but the reporters interrupt with "NEVER MIND THAT, TELL US WHAT'S WRONG WITH THE SUN!"
}}

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

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

How worried you should be if you see local reporters interviewing scientists about a breaking news story, by field:

[Chart showing "More worried" with an arrow to the right with these marks in progressively more worrying sequence.]
Archeologist 
Economist 
Nutritionist 
Criminologist 
Ornithologist 
Botanist 
Marine Biologist 
Entomologist 
Astronomer 
Virologist 
Vulcanologist 
Astronomer who studies the sun

Tag:They always try to explain that they're called 'solar physicists', but the reporters interrupt with "NEVER MIND THAT, TELL US WHAT'S WRONG WITH THE SUN!"

{{comic discussion}}

1895: Worrying Scientist Interviews

2017-09-27T14:45:46Z

DarkJMKnight:

{{comic
| number = 1895
| date = September 27, 2017
| title = Worrying Scientist Interviews
| image = worrying_scientist_interviews.png
| titletext = They always try to explain that they're called 'solar physicists', but the reporters interrupt with "NEVER MIND THAT, TELL US WHAT'S WRONG WITH THE SUN!"
}}

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

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

How worried you should be if you see local reporters interviewing scientists about a breaking news story, by field:

Chart showing "More worried" with an arrow to the right with these marks in progressively more worrying sequence:
Archeologist 
Economist 
Nutritionist 
Criminologist 
Ornithologist 
Botanist 
Marine Biologist 
Entomologist 
Astronomer 
Virologist 
Vulcanologist 
Astronomer who studies the sun

Tag:They always try to explain that they're called 'solar physicists', but the reporters interrupt with "NEVER MIND THAT, TELL US WHAT'S WRONG WITH THE SUN!"

{{comic discussion}}

1895: Worrying Scientist Interviews

2017-09-27T14:43:06Z

DarkJMKnight:

{{comic
| number = 1895
| date = September 27, 2017
| title = Worrying Scientist Interviews
| image = worrying_scientist_interviews.png
| titletext = They always try to explain that they're called 'solar physicists', but the reporters interrupt with "NEVER MIND THAT, TELL US WHAT'S WRONG WITH THE SUN!"
}}

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

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

How worries you should be if you see local reporters interviewing scientists about a breaking news story, by field:

Chart showing "More worried" with an arrow to the right with these marks in progressively more worrying sequence:
Archeologist
Economist
Nutritionist
Criminologist
Ornithologist
Botanist
Marine Biologist
Entomologist
Astronomer
Virologist
Vulcanologist
Astronomer who studies the sun

Tag:
The always try to explain that they're called 'solar physicists', but he reporters interrupt with "NEVER MIND THAT, TELL US WHAT'S WROG WITH THE SUN!"

{{comic discussion}}

Talk:1882: Color Models

2017-08-29T11:14:04Z

DarkJMKnight:

For those who want to know a bit more about color, [https://www.handprint.com/LS/CVS/color.html this site] is a good start. [[User:Zmatt|Zmatt]] ([[User talk:Zmatt|talk]]) 15:08, 28 August 2017 (UTC)

This comic shows the trend of having a simple and satisfactory explanation for something, and the exasperation with repeatedly realizing the inadequacy of the explanation, making revisions, and having a more complex yet still inadequate model.

As Randall began his schooling, he learned that mixing the primary colours of pigment (red, blue, and yellow) together he could create almost any colour, so colour must be a combination of those 3 colours.

He also learned about rainbows, and that the colours in the rainbow were just different wavelengths of light. Somehow these different wavelengths created unique colours.

As Randall got older, philosophy and a discussion on perception came into play, and Randall came to the realization that his experiences are analogous to but not necessarily the same as his peers.

As he got older, Randall learned about colour spaces as used in pigments, light, and printing, possibly from computer science (Red, Green, Blue; Red, Yellow, Blue; Cyan, Magenta, Yellow, Key) as well as the physics of electromagnetic rays and the biology of vision, understanding that visible light is a small portion of the electromagnetic spectrum - one crudely interpreted by the 3 types of cones in our eyeballs.

Randall then learned about the opponent process model, wherein the signal from cones are not interpreted individually, but in difference to one another. "Responses to one color of an opponent channel are antagonistic to those to the other color. That is, opposite opponent colors are never perceived together – there is no "greenish red" or "yellowish blue"." (from wikipedia)

After that, Randall comes to understand the modeling of colour spaces and the design and limits of human visual perception - despite only having three cones, color space cannot be made into a triangle and still cover the gamut of human colour experience.

Klein manifolds are beyond me, you'll have to fill in something about that.

Eventually, the modeling becomes so complex (and yet still unsatisfactory) that Randall hopes it becomes someone else's problem. [[Special:Contributions/108.162.238.5|108.162.238.5]] 15:50, 28 August 2017 (UTC)MagnusVortex

I'm familiar with klein manifolds, they're peculiar 4D dimensional topological objects related to mobius strips. I have no Idea how they might relate to color, and doing a search for "a hyperdimensional four-sided quantum Klein manifold" returned pictures of bicycles...

It might be good to point out in the explaination that he progresses from a dual nature of color (light, and paint) at the beginning and then trends to a unified explaination of color. [[Special:Contributions/172.68.142.179|172.68.142.179]] 18:27, 28 August 2017 (UTC) Sam

: Yes those are great looking bikes and are called Klein Quantum racing bikes... so Google did its job of keyword matching. [[User:Rtanenbaum|Rtanenbaum]] ([[User talk:Rtanenbaum|talk]]) 20:40, 28 August 2017 (UTC)

;The beauty of explainxkcd
The explanation of this comment is a great example of why this site is delightful — and nigh-invaluable! Thanks, regulars, for doing the work to help us understand all this.{{unsigned ip|108.162.246.101}}

----

Text explanation

I think the explanation of the text is missing an important point. It starts like it's about the philosophal question of "the same color for everybody", but ends with a very mundane explanation, which I think quite funny.

[[Special:Contributions/141.101.69.9|141.101.69.9]] 21:18, 28 August 2017 (UTC) Loïc

Yes, the description needs to include the fact that the top reference to color being unknowable is a reference to [https://en.wikipedia.org/wiki/Qualia qualia]. The brain of one individual may interpret colors differently than the brain of another individual, but since we would all use the same words for our interpretations of the same wavelengths, we can't really know if how I see blue is the same as how you see blue, hence that reference. But then in the tag, he has swapped out the reason for our different interpretations for the same color, blaming our browsers instead of our brains.

[[User:DarkJMKnight|DarkJMKnight]] ([[User talk:DarkJMKnight|talk]]) 11:14, 29 August 2017 (UTC)

----

"As the 4th dimension is time, the color space would probably change all the time."

...no. No. I'm removing that. Just... no.

[[User:Hakr14|Hakr14]] ([[User talk:Hakr14|talk]]) 23:03, 28 August 2017 (UTC)

Talk:1292: Pi vs. Tau

2013-11-18T20:04:21Z

DarkJMKnight:

I started an explanation. Hopefully others will help improve it, as I don't think it's quite adequate. [[Special:Contributions/199.27.130.174|199.27.130.174]] 05:32, 18 November 2013 (UTC)

The comic currently shows the symbol π (pi) in all three cases, but it should have the symbol τ (tau) in the rightmost case. I'm sure there is a compromise symbol "pau" too. Maybe with a deformed left leg? [[Special:Contributions/141.101.97.4|141.101.97.4]] 07:07, 18 November 2013 (UTC)

WolframAlpha gives
<pre>
4.5545743763144164456766617143366171162404440766665105335330776311513504520604364524762740226212061363100001776216741750712622557020442741544760057441760026766230424023460366047331305225241275347777145543054127636365666430221066167347236617261603127725745513663702031155234027041040155322217227723576660045156156303357534162372112340027743775672417274565277274565735325624457113522164166560115654407251403563246444122664066521461311773474046032763760765740133706761276420415672577471077133607673035331070364705651055376634161405567176532346433567731715723623721267302576735154761375545411215522177775706407470673020025353246535120744232706060324711633457720155013202527060250466252665661576165164140301645132275526153126363575631176312270212441433434206352313125326760006365710744276056412434626534152021052065172556442150110056601034116570607064550553636566432544260105637423220411372664024454234201642615033200331506013362432026775605543212342336511350621361642654426372425415023071413764173735461042064323757413414533013..._8</pre> which does indeed have four 666 sequences. [[Special:Contributions/141.101.99.254|141.101.99.254]] 08:06, 18 November 2013 (UTC)
This number contains 7777, 000 and 444 twice, though. [[Special:Contributions/141.101.93.11|141.101.93.11]] 09:08, 18 November 2013 (UTC)

Wrote the transcript, not sure if I explained the visual well enough, so I left the incomplete tag if someone else has a better idea. Should suffice for understanding however, considering the content [[Special:Contributions/108.162.248.18|108.162.248.18]] 08:55, 18 November 2013 (UTC)

----

(The discussion about different results was trimmed)

Wolfram gives the result with 666

http://www.wolframalpha.com/input/?i=1.5+pi+octal
<pre>
4.554574376314416445676661714336617116240444076666510533533077631151350452060436452476274022621206136310000177621674175071262255702044274154476005744176002676623042402346036604733130522524127534777714554305412763636566643022
</pre>
The Unix arbitrary precision calculator gives the result without

$ echo "scale=200; obase=8; 6*a(1)" | bc -l
<pre>
4.554574376314416443236234514475050122425471573015650314763354527003043167712611655054674757031331252340351471657646433317273112431020107644727072362457372164022043765215506554422014311615574251563446213636251744101107770257
</pre>
Any suggestions how we can check them?

"Randall says so" is probably correct, but insufficient :-) {{unsigned|Mike}}

:Please use the <nowiki><pre></nowiki> tag for this long numbers.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 09:20, 18 November 2013 (UTC)

Testing Wolfram Alpha with <pre>4.55457437631441644567666171433661711624044407666651053353307763115135045206043645247627402262120613631000177621674175071262255_8 in decimal</pre> and <pre>4.55457437631441644567666171433661711624044407666651053353307763115135045206043645247627402262120613631000_8 in decimal</pre> both indicate the approximation is only accurate to a limited degree.
http://www.wolframalpha.com/input/?i=4.55457437631441644567666171433661711624044407666651053353307763115135045206043645247627402262120613631000177621674175071262255_8+in+decimal
http://www.wolframalpha.com/input/?i=4.55457437631441644567666171433661711624044407666651053353307763115135045206043645247627402262120613631000177621674175071262255_8+in+decimal

The method I used to get the value I put in the text was; I used the following command to generate my approximation:
<pre>echo 'scale=200; obase=8; a(1) * 6' | bc -l | tr -d ' \\\n' ; echo</pre> which outputs<pre>
4.554574376314416443236234514475050122425471573015650314763354527003043167712611655054674757031331252340351471657646433317273112431020107644727072362457372164022043765215506554422014311615574251563446213636251744101107770257
</pre>
In 'bc'', a(1) is arctangent of 1 (i.e. 45 degrees, or pi/4); (pi/4 * 6) should be equal to 'pau'. I additionally checked the result using base 2 encoding, and converted each three bit binary value into an octal value. The decimal value of pi (using a(1) * 4) matches with the value of pi to at lease 1000 digits.
[[Special:Contributions/173.245.54.86|173.245.54.86]] 09:21, 18 November 2013 (UTC)

Both Maxima and the GNU Emacs calculator output as the first 1000 octal digits:
<pre>
4.5545743763144164432362345144750501224254715730156503147633545270030431677126116550546747570313312523403514716576464333172731124310201076447270723624573721640220437652155065544220143116155742515634462136362517441011077702611156024117447125224176203716336742057353303216470257662666744627534325504334506002730517102547504145216661211250027531716641276765735563341721214013553453654106045245066401141437740626707757305450703606440651111775270032710035521352101513622062164457304326450524432531652666626042202562202550566425643040556365710250031642467447605663240661743600041052212627767073277600402572027316222345356036301002572541750000114422036312122341474267232761775450071652613627306745074150251171507720277250030270442257106542456441722455345340370205646442156334125564557520336340223313312556634450170626417234376702443117031135045420165467426237454754566012204316130023063506430063362203021262434464410604275224606523356702572610031171344411766505734615256121034660773306140032365326415773227551
</pre>
This also agrees with the first 220 digits of the previous result (last two digits above are 57 vs 61 here, maybe due to rounding when converting to octal). Again, no 666 within the first 200 digits. The Wolfram result deviates from this at the 18th digit already. --[[User:Ulm|ulm]] ([[User talk:Ulm|talk]]) 10:21, 18 November 2013 (UTC)

Also e+2 does not contain the substring '666':
<pre>echo "scale=200; obase=8; e(1) + 2" | bc -l</pre>
<pre>4.55760521305053551246527734254200471723636166134705407470551551265170233101050620637674622347347044466373713722774330661414353543664033100253542141365517370755272577262541110317650765740633550205306625</pre>--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 10:43, 18 November 2013 (UTC)

: A sudden flash of realization: are we getting nerd-sniped here?--[[Special:Contributions/108.162.254.168|108.162.254.168]] 11:55, 18 November 2013 (UTC)

: The claim is clearly about e+2, making Dgbrt's comment closest to the right direction. [[Special:Contributions/173.245.54.40|173.245.54.40]] 12:03, 18 November 2013 (UTC)

When I take Wolfram alpha's octal(pi*1.5) I get the first 303 (base 10) characters as this:
<pre>
4.554574376314416445676661714336617116240444076666510533533077631151350452060436452476274022621206136310000177621674175071262255702044274154476005744176002676623042402346036604733130522524127534777714554305412763636566643022106616734723661726160312772574551366370203115523402704104015532221722772357666
</pre>
200(base 10) is 310(base 8) so in the fist '200' characters, 666 shows up 4 times (5 if you count 6666 as twice?) [[User:Xami|Xami]] ([[User talk:Xami|talk]]) 14:01, 18 November 2013 (UTC)

: The Wolfram result is what you get when you calculate pi*3/2 in decimal, round to 14 digits after the decimal point and then convert to octal. That is, 4.7123889803846910 converted to octal. Definitely, this won't give you 200 digits precision. --[[User:Ulm|ulm]] ([[User talk:Ulm|talk]]) 15:15, 18 November 2013 (UTC)
:: It lines up too perfectly to be a coincidence. It fits all the requirements: has 666 four times within 2008 digits, and although 0000, 222, 444, and 7777 appear, they only appear once as a run. You can't double count 7777 as two 777's because it is a single run. If WolframAlpha doesn't give the correct precision, it is likely that Randall made the same error. --[[User:RainbowDash|RainbowDash]] ([[User talk:RainbowDash|talk]]) 16:59, 18 November 2013 (UTC)

Being τ, tau, is already being expressed in terms of π, pi, it shows bias. (Though I think Pau would lead to some interesting spherical geometry equations. ~~Drifter

---

I am in favour of just calling it ti(e). --[[Special:Contributions/173.245.53.184|173.245.53.184]] 17:52, 18 November 2013 (UTC)

---

There are real world uses to both Tau and Pi: Pi is the number that relates to what you get when you measure a circle (the distanced around divided by the distance across); and Tau is get when you draw a circle (the distance around divided by the distance from the center). It is the difference between a mic (aka "micrometer" http://en.wikipedia.org/wiki/Micrometer ) and a protractor. Tau might have some mathematical advantages in both 2D and 3D in that it has no integer attached to it to find either circumference (2D) or surface area (3D) which makes radians and solid angles simpler. However, that advantage is lost in other dimensions and for the area of a circle.

Pau, of course, has a 61% chance of going to the dribbling spheroid hall of fame. (ref: http://www.basketball-reference.com/players/g/gasolpa01.html ), to which neither Tau nor Pi can hold a candle.~~Remo ( [[Special:Contributions/199.27.128.183|199.27.128.183]] 19:19, 18 November 2013 (UTC) )

---

The differences between Wolfram and BC really bothered me since I have used both for precision calculation in the past. The long and short of the matter, having done most of the maths 'long hand', BC is correct, Wolfram is wrong, and sadly, Randall was also wrong. It seems as tho Wolfram is rounding pi*1.5 to around 15 decimals but leaving the 9 repeating before converting to Octal.

If you take the output of octal(pi * 1.5) and paste it back into the input like so:
<pre>
4.554574376314416445676661714336617116240444076666510533533077631151350452060436452476274022621206136310000177621674175071262255702044274154476005744176002676623042402346036604733130522524127534777_8
</pre>
Wolfram gives you back (converted to decimal):
<pre>
4.71238898038468999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
</pre>
If you give that same input to BC and ask it to convert to decimal you get:
<pre>
4.712388980384689999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999992894219160392567888
</pre>
If you do the math long hand out to 55 decimal places, pi * 1.5 equals:
<pre>
4.712388980384689857693965074919254326295754099062658731462416...
</pre>
Converting that by hand into octal is a bit of a pain, but if you do, at the 18th decimal place where BC and Wolfram differ you end up with the following:
<pre>
0.000000000000000183697019872102976583909889841150158731462416... is your remainder to be converted so far
0.000000000000000055511151231257827021181583404541015625 = 8 ^ -18
</pre>
Wolfram gives the 18th decimal as 5, BC as 3. I can't see 5 going into 18 5 times, but 3 times fits nicely.
--[[User:DarkJMKnight|DarkJMKnight]] ([[User talk:DarkJMKnight|talk]]) 20:04, 18 November 2013 (UTC)