explain xkcd - User contributions [en]

Talk:1433: Lightsaber

2014-10-15T15:16:09Z

141.101.64.23:

I seem to remember seeing somewhere that lightsabers are actually not lasers but rather plasma held in that shape by some sort of force field. I think it should be in the explanation if it is true. [[User:Athang|Athang]] ([[User talk:Athang|talk]]) 06:11, 13 October 2014 (UTC)
:I'd just like to know what "real laser"s have to do with lightsabers. (Other than little kids using the wrong name.) [[Special:Contributions/103.22.201.120|103.22.201.120]] 11:55, 13 October 2014 (UTC)

Most of "scientific" explanations of lightsaber (and blaster bolts) says about plasma contained in magnetic field. For example check this SE http://scifi.stackexchange.com/questions/6478.
Endless "laser sword" pun was also used in http://www.collegehumor.com/video/6704463/troopers-laser-sword, without Luke but with massive hull breach. [[Special:Contributions/108.162.231.214|108.162.231.214]] 06:38, 13 October 2014 (UTC)PTwr

One joking "explanation" of the light sabre conjured long ago on a newsgroup I was on had used the Fourier analysis. It proposed that the "handle" emits multiple beams of light with very well defined frequencies and amplitudes, corresponding to a Fourier series for a pulse wave with a low duty cycle - so the waveforms emitted cancel themselves after a short distance. The joke went on, saying that since the sum of the Fourier series is periodic, someone practicing the sabre on the Earth can accidentally chop off the head of someone walking on the Moon. [[Special:Contributions/108.162.254.29|108.162.254.29]] 07:26, 13 October 2014 (UTC)

I don't think this has anything to do with the Hull Breach card game. The sentence "Hull breach all along sector five" does however sound like something from Star Trek and not like Star Wars.[[User:Condor70|Condor70]] ([[User talk:Condor70|talk]]) 12:07, 13 October 2014 (UTC)

There is a XKCD What If discussion on infinite lasers at http://what-if.xkcd.com/109/ [[Special:Contributions/141.101.99.113|141.101.99.113]] 12:17, 13 October 2014 (UTC)

"'''Because Vader slightly tilts the active lightsaber, the beam ends up slicing straight through the hull of a large section of the Death Star. '''" Wouldn't it would cause a breach the moment he turned it on, not waiting until he tilts it? [[User:Lomky|Lomky]] ([[User talk:Lomky|talk]]) 15:07, 13 October 2014 (UTC)
:Yes, but the breach would be highly localized (the same diameter as the blade) until he tilts it. If he does so in the center of the sphere, leverage means that a slight angle change in the emitter means a huge change at the other end of the beam.[[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 15:34, 13 October 2014 (UTC)
::Darth Vader may be more machine than man, but don't you think you're overestimating his ability to hold his hand steady? You seem to be suggesting his hand wouldn't tremor enough to cause even the tiniest perturbations in the angle.[[User:Diszy|Diszy]] ([[User talk:Diszy|talk]]) 19:29, 13 October 2014 (UTC)
:::How far are they from the hull? The original breach would still be relatively localized (on the order of 1-2% of their distance from the hull), so if they're within a few hundred meters from the boundary it shouldn't be particularly large. (That's even assuming they're on the Death Star in the first place, as the IP below me helpfully points out; could be that the original vector simply didn't intersect the Death Star at all.) Or of course it could be the original - it's only been several seconds or so, maybe they only noticed it that moment anyway. A cool calculation I don't have time to do right now: assuming the blade covered a plane sector of, say, 15 degrees (I'm ignoring the twitches for a moment, though it's easy to see that they don't change the answer much), and assuming it didn't hit any nearby planets such as Endor, approximately how many planets it would've hit on its way from the galaxy? Same question for stars (though I suppose a lightsaber blade won't do much to a star). [[Special:Contributions/141.101.64.23|141.101.64.23]] 06:51, 14 October 2014 (UTC)
::::They're on Endor (in the movie, at least). https://www.youtube.com/watch?v=WDnoczxzQyg If the beam intersects the Death Star, it would be many hundreds of KM away. Any perturbations would be HUGE at that distance. Also, the XKCD What If book actually addresses the question of the likelihood that a beam hits anything. [[User:Diszy|Diszy]] ([[User talk:Diszy|talk]]) 12:03, 15 October 2014 (UTC)
:::::I was basically saying that the beam ''didn't'' intersect the Death Star until being moved in panel four. As for the book, if you're referring to What If #109, it involves a stationary (or single-burst) laser; numbers for a moving laser (that sweeps through a section of a plane) would be different. I'm also ignoring the speed of light (which is kind of important when we're talking about interstellar distances). Estimating based on [[1276: Angular Size]], seems that the chance of hitting a star would be roughly (laptop size/Earth size)*(galaxy size/Proxima distance)*15/360, which comes out to one in several thousand. Which is less than I expected, actually. [[Special:Contributions/141.101.64.23|141.101.64.23]] 15:16, 15 October 2014 (UTC)

The scene referred to in Return of the Jedi, actually takes place on the surface of Endors moon. There are trees in the background: https://www.youtube.com/watch?v=WDnoczxzQyg [[Special:Contributions/141.101.81.222|141.101.81.222]] 15:20, 13 October 2014 (UTC)

Actually, the title text says "A long time in the future, in a galaxy...", not "ago". [[Special:Contributions/108.162.216.26|108.162.216.26]] 12:25, 13 October 2014 (UTC)
: Who said otherwise? "'''The Star Wars opening crawl''' starts with the text "A long time ago..." {{unsigned ip|199.27.128.117}}

When I first read this, I took it as a game of one-up-manship. I build something, you build something better, I build something even better, you build something cooler, etc in an ever escalating spiral of coolness. So, here, Luke has built a long sabre as a way of one-upping his father, who then asks "where does [this competition] end?" Luke's response is taht the competition, like his laser sword, never ends. That also seems to fit in neatly with Randall's penchant for puns. OTOH, I could just be making up stuff inside my head :D JonS

<GASP> We now have one of the two variables needed to find the Death Star! We have direction, now all we need is distance! {{unsigned ip|108.162.217.137}}

"'''an unusual gamma ray burst in 2008, visible to the human eye'''" - I know what is ''meant'', but perhaps a rewording? [[Special:Contributions/141.101.99.118|141.101.99.118]] 12:56, 15 October 2014 (UTC)

Talk:1433: Lightsaber

2014-10-14T06:51:09Z

141.101.64.23:

I seem to remember seeing somewhere that lightsabers are actually not lasers but rather plasma held in that shape by some sort of force field. I think it should be in the explanation if it is true. [[User:Athang|Athang]] ([[User talk:Athang|talk]]) 06:11, 13 October 2014 (UTC)
:I'd just like to know what "real laser"s have to do with lightsabers. (Other than little kids using the wrong name.) [[Special:Contributions/103.22.201.120|103.22.201.120]] 11:55, 13 October 2014 (UTC)

Most of "scientific" explanations of lightsaber (and blaster bolts) says about plasma contained in magnetic field. For example check this SE http://scifi.stackexchange.com/questions/6478.
Endless "laser sword" pun was also used in http://www.collegehumor.com/video/6704463/troopers-laser-sword, without Luke but with massive hull breach. [[Special:Contributions/108.162.231.214|108.162.231.214]] 06:38, 13 October 2014 (UTC)PTwr

One joking "explanation" of the light sabre conjured long ago on a newsgroup I was on had used the Fourier analysis. It proposed that the "handle" emits multiple beams of light with very well defined frequencies and amplitudes, corresponding to a Fourier series for a pulse wave with a low duty cycle - so the waveforms emitted cancel themselves after a short distance. The joke went on, saying that since the sum of the Fourier series is periodic, someone practicing the sabre on the Earth can accidentally chop off the head of someone walking on the Moon. [[Special:Contributions/108.162.254.29|108.162.254.29]] 07:26, 13 October 2014 (UTC)

I don't think this has anything to do with the Hull Breach card game. The sentence "Hull breach all along sector five" does however sound like something from Star Trek and not like Star Wars.[[User:Condor70|Condor70]] ([[User talk:Condor70|talk]]) 12:07, 13 October 2014 (UTC)

There is a XKCD What If discussion on infinite lasers at http://what-if.xkcd.com/109/ [[Special:Contributions/141.101.99.113|141.101.99.113]] 12:17, 13 October 2014 (UTC)

"'''Because Vader slightly tilts the active lightsaber, the beam ends up slicing straight through the hull of a large section of the Death Star. '''" Wouldn't it would cause a breach the moment he turned it on, not waiting until he tilts it? [[User:Lomky|Lomky]] ([[User talk:Lomky|talk]]) 15:07, 13 October 2014 (UTC)
:Yes, but the breach would be highly localized (the same diameter as the blade) until he tilts it. If he does so in the center of the sphere, leverage means that a slight angle change in the emitter means a huge change at the other end of the beam.[[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 15:34, 13 October 2014 (UTC)
::Darth Vader may be more machine than man, but don't you think you're overestimating his ability to hold his hand steady? You seem to be suggesting his hand wouldn't tremor enough to cause even the tiniest perturbations in the angle.[[User:Diszy|Diszy]] ([[User talk:Diszy|talk]]) 19:29, 13 October 2014 (UTC)
:::How far are they from the hull? The original breach would still be relatively localized (on the order of 1-2% of their distance from the hull), so if they're within a few hundred meters from the boundary it shouldn't be particularly large. (That's even assuming they're on the Death Star in the first place, as the IP below me helpfully points out; could be that the original vector simply didn't intersect the Death Star at all.) Or of course it could be the original - it's only been several seconds or so, maybe they only noticed it that moment anyway. A cool calculation I don't have time to do right now: assuming the blade covered a plane sector of, say, 15 degrees (I'm ignoring the twitches for a moment, though it's easy to see that they don't change the answer much), and assuming it didn't hit any nearby planets such as Endor, approximately how many planets it would've hit on its way from the galaxy? Same question for stars (though I suppose a lightsaber blade won't do much to a star). [[Special:Contributions/141.101.64.23|141.101.64.23]] 06:51, 14 October 2014 (UTC)

The scene referred to in Return of the Jedi, actually takes place on the surface of Endors moon. There are trees in the background: https://www.youtube.com/watch?v=WDnoczxzQyg [[Special:Contributions/141.101.81.222|141.101.81.222]] 15:20, 13 October 2014 (UTC)

Actually, the title text says "A long time in the future, in a galaxy...", not "ago". [[Special:Contributions/108.162.216.26|108.162.216.26]] 12:25, 13 October 2014 (UTC)
: Who said otherwise? "'''The Star Wars opening crawl''' starts with the text "A long time ago..." {{unsigned ip|199.27.128.117}}

When I first read this, I took it as a game of one-up-manship. I build something, you build something better, I build something even better, you build something cooler, etc in an ever escalating spiral of coolness. So, here, Luke has built a long sabre as a way of one-upping his father, who then asks "where does [this competition] end?" Luke's response is taht the competition, like his laser sword, never ends. That also seems to fit in neatly with Randall's penchant for puns. OTOH, I could just be making up stuff inside my head :D JonS

<GASP> We now have one of the two variables needed to find the Death Star! We have direction, now all we need is distance! {{unsigned ip|108.162.217.137}}

Talk:221: Random Number

2014-08-22T01:03:51Z

141.101.64.23: /* Playstation 3 jailbreak reference? */ new section

The syntax looks like perfectly valid java to me.[[Special:Contributions/213.64.1.189|213.64.1.189]] 22:00, 11 March 2013 (UTC)

Looks like Java to me too.{{unsigned ip|139.216.242.254}}
:How can Java come to mind when it is pure C syntax, which predates Java by several years and is arguably better known. A feature of most languages is that they have a "C-like syntax". See, a whole page on Wikipedia - http://en.wikipedia.org/wiki/List_of_C-based_programming_languages [[Special:Contributions/122.161.20.238|122.161.20.238]] 19:53, 22 August 2013 (UTC)
::"C-like syntax" is the best explain, this covers all. Even when I disagree that it's better known than Java these days.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 21:04, 22 August 2013 (UTC)
:::Just to be particularly pedantic, the double slash for the comment (which is generally utilised in object oriented C-style languages) should be avoided in C to retain backwards compatibility with C89, although it's a valid construct in C99. I'd offer, too, that the lack of library inclusion suggests this isn't necessarily Java, though it's been a couple years since I've had the opportunity to code in it. [[User:Thokling|Thokling]] ([[User talk:Thokling|talk]]) 15:35, 20 September 2013 (UTC)

As a proof of good joke, RFC 1149 was successfully implemented several times. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 08:55, 11 May 2013 (UTC)

Actually, a poor “random” function like “return 4;” would be quickly determined by statistical test tools (Diehard, Dieharder, etc.) to generate very poor random number. [[User:Samiam|Samiam]] ([[User talk:Samiam|talk]]) 19:55, 28 October 2013 (UTC)
:The number is random, I'm sure Randall really did this "fair dice roll". And even the name of the function is correct, it just returns a random number. A programmer would expect a random number generator, but Randall can't roll the dice all the time.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 21:37, 28 October 2013 (UTC)

:<<sound of crickets chirping>> [[Special:Contributions/108.162.219.58|108.162.219.58]] 02:24, 6 February 2014 (UTC)

== Playstation 3 jailbreak reference? ==

Isn't this a reference to Sony Playstation 3's random number generator function that allowed to discover the private key to 3.55 firmware?