explain xkcd - User contributions [en]

902: Darmok and Jalad

2015-01-16T20:10:54Z

108.162.250.208: /* Explanation */ gr

{{comic
| number = 902
| date = May 23, 2011
| title = Darmok and Jalad
| image = darmok_and_jalad.png
| titletext = I wonder how often Patrick Stewart has Darmok flashbacks when talking to Star Trek fans.
}}

==Explanation==
This comic is a parody of the {{w|Star Trek: The Next Generation}} episode "{{w|Darmok}}" in which [http://en.memory-alpha.org/wiki/Jean-Luc_Picard Captain Picard] and the Enterprise crew meet with a [http://en.memory-alpha.org/wiki/The_Children_of_Tama Tamarian] ship. They can translate the individual words of Tamarian with perfect accuracy, but the Tamarians communicate using metaphors based on their own history and culture—without these cultural references, the Enterprise crew are unable to understand what the Tamarians are actually saying. "Darmok and Jalad at Tanagra" is repeated many times in this episode by the Tamarian captain, Dathon. Picard is eventually able to decipher the line to discover that it was a story of two warriors marooned on an island (Tanagra) who work together to defeat a common foe. The alien's intention is that he and Picard work together to defeat a monster as a way to cement ties between the Tamarians and the [http://en.memory-alpha.org/wiki/United_Federation_of_Planets Federation].

In the comic, instead of suggesting a dramatic gesture to achieve a diplomatic breakthrough, the alien seems to be suggesting a one-night stand. It is not clear if he is chatting up [http://en.memory-alpha.org/wiki/Deanna_Troi Deanna Troi] (who has the long curly hair) or Picard. However, given that in the original episode Darmok and Jalad (the two warriors) were metaphorically identified with Dathon and Picard, it seems likely that he is flirting with Picard.

The title text suggests that the actor {{w|Patrick Stewart}}, who played Captain Picard, might find Star Trek fans indecipherable, in the same way that Captain Picard found the Tamarians indecipherable. This is a joke about how Star Trek fans stereotypically make constant references to the franchise which are so dense and obscure that even the program's actors might find them impossible to understand.

==Transcript==
:[Captain Dathon is seen on a communications screen.]
:Alien: Darmok and Jalad at Kalenda's!

:[Jean-Luc Picard and Deanna Troi stand next to each other, looking off to the right.]
:Picard: Their language must be based on folklore and metaphor! Computer! Search cultural archives for Darmok-Jalad-Kalenda!

:[Picard and Troi listen to the response.]
:Computer (off-panel): In Tamarian legend, Darmok and Jalad got totally wasted and hooked up at a party at Kalenda's.

:[Dathon is seen on the communications screen again, winking.]
:''WIIIIIINK''

{{comic discussion}}
[[Category:Language]]

Talk:1441: Turnabout

2014-10-31T06:38:52Z

108.162.250.208: Created page with "In the few seconds the photons take to get to the moon and back, the earth has moved enough on its axis that the reflected beam from a perfect retroreflector is not gonna hit ..."

In the few seconds the photons take to get to the moon and back, the earth has moved enough on its axis that the reflected beam from a perfect retroreflector is not gonna hit the protagonist.

The retroreflectors for the Apollo missions were deliberately spoiled so they return six slightly offset beams, angled such that photons from one of them will go back near enough to the source.

Oh, and of course there's also the whole r^4 thing too.

1360: Old Files

2014-04-25T07:18:12Z

108.162.250.208: /* Files */

{{comic
| number = 1360
| date = April 25, 2014
| title = Old Files
| image = old_files.png
| titletext = Wow, ANIMORPHS-NOVEL.RTF? Just gonna, uh, go through and delete that from all my archives real quick.
}}

==Explanation==
{{incomplete|Missing explanations for most of the various files.}}
Cueball is sifting through a pile of old files, either a theoretical one that exists on a hard drive, making fun of how hard it is to search through old files, or a real room of old hard drives. He discovers several files he is embarrassed about, including a poetry file that surprises him, since he does not remember writing poetry, and an "Animorphs Novel" mentioned in the title text, most likely a fan fiction of the Animorphs series, although possibly a copy of one of the original books.

This comic came out the day after [http://news.sky.com/story/1248397/andy-warhol-originals-found-on-floppy-disk Sky News published the story] of original [[wikipedia:Andy Warhol|Andy Warhol]] artwork, created in 1985 on an [[wikipedia:Amiga 1000|Amiga 1000]], was recovered from recently found floppy disks.

=== Files ===
* [[wikipedia:Angband|Angband]] is a rogue-like computer game.
* [[wikipedia:Kazaa|Kazaa]] is an internet file sharing service.
* [[wikipedia:QBasic|QBasic]] is an IDE and intepreter for a dialect of the BASIC programming language, originally bundled with MS-DOS 5.0 and newer, and [[wikipedia:Gorillas (video game)|Gorilla.bas]] is one of the games that came with QBasic.
* [[wikipedia:ICQ|ICQ]] is an early (1996) instant messenger client.
* [[wikipedia:Elasto_Mania|Elasto Maina]] is a 2D motorbike computer game

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

Talk:162: Angular Momentum

2014-02-23T02:48:39Z

108.162.250.208:

The issue date is not given, as i don't have a clue about it. Could someone fix this? [[User:Rikthoff|Rikthoff]] ([[User talk:Rikthoff|talk]]) 19:30, 3 August 2012 (EDT)

:When the page was updated to the new comic template by [[User:Bpothier]] he fixed the date. [[User:Lcarsos|lcarsos]] ([[User talk:Lcarsos|talk]]) 20:48, 28 August 2012 (UTC)

That actually is a neat physics puzzle, which has probably (i.e. certainly) been addressed somewhere on the net. I may incorporate that some day. --[[User:Quicksilver|Quicksilver]] ([[User talk:Quicksilver|talk]]) 05:58, 24 August 2013 (UTC)

I tried to calculate the change in Earth's period, assuming that she was standing in the north pole (latitude = 90º N), where her spinning would have more effect. I either did something wrong, or my TI-84 Plus is not capable of detecting the very small effect her spinning would have on the Earth's rotation. I assumed the Earth had a period of exactly 24 hours, and got the same value to the second, even if she was spinning at 1000 turns per second, which seems like a lot.

Here's the formula:

L_Earth_i = L_Earth_f + L_spinner <=>

I_Earth * (2*PI)/T_Earth_i = I_Earth * (2*PI)/T_Earth_f + I_spinner* (2*PI) * f_spinner <=>

(1/T_Earth_f) = (1/T_Earth_i) - (I_spinner/I_Earth)*f_spinner <=>

T_Earth_f = 1/((1/T_Earth_i) - (I_spinner/I_Earth)*f_spinner)

Where the variables have names in the format:

[variable name]_[object it refers to]_[situation (i or f stand for initial and final)]

L = Angular Moment

I = Moment of Inertia

T = Period of rotation about one's axis

f = frequency

I used as values:

T_Earth_i = 86400 seconds (24 hours exactly)

I_spinner = 62,04 Kg.m^2 (Found on Wolfram|Alpha, for a 62Kg adult human being)

I_Earth = 8,03e+37 Kg.m^2 (http://scienceworld.wolfram.com/physics/MomentofInertiaEarth.html)

f_spinner = the frequency of the woman's spinning in complete turns per second. {{unsigned ip|2.82.142.28}}

:Taking that a bit further, the relative decrease is:

(T_Earth_f - T_Earth_i)/T_Earth_i = 1 / (I_Earth/(I_spinner*T_Earth_i*f_spinner) - 1)
= 1 / ( 1.5 e+28 - 1) ~= 67 e-30

:Fwiw, the absolute value is 5.767 yocto-seconds. If the ''entire'' world population would spin at that 1000 turns per second (and at favourable locations as in your assumptions), the effect will still be a measly 0.041 pico-seconds. So T_Earth_f = 86 399.999 999 999 999 958 ... But the TI-84 only has about 14 digits precision, i believe, so even that won't show up. -- [[Special:Contributions/173.245.51.210|173.245.51.210]] 22:46, 30 October 2013 (UTC)

Is it possible for someone to write an equation that factors in latitude (and, if relevant, longitude) that we could plug our locations into and get a value from? That would be awesome. Thanks. [[Special:Contributions/108.162.250.208|108.162.250.208]] 02:48, 23 February 2014 (UTC)