explain xkcd - User contributions [en]

1189: Voyager 1

2013-03-22T10:07:17Z

80.219.253.33: /* Explanation */ Don't think he made a joke on the concentration camp ...

{{comic
| number = 1189
| date = March 22, 2013
| title = Voyager 1
| image = voyager_1.png
| titletext = So far Voyager 1 has 'left the Solar System' by passing through the termination shock three times, the heliopause twice, and once each through the heliosheath, heliosphere, heliodrome, auroral discontinuity, Heaviside layer, trans-Neptunian panic zone, magnetogap, US Census Bureau Solar System statistical boundary, Kuiper gauntlet, Oort void, and crystal sphere holding the fixed stars.
}}

==Explanation==
''{{w|Voyager 1}}'' is a U.S. space probe launched in 1977 to study the outer reaches of the Solar System and beyond. Popular press has on several occasions announced that it “has left the solar system” – at each point when a boundary has been confirmed or a major event has taken place – the fact is that there is no strictly defined and recognizable boundary of the solar system.

The alt-text lists several such possible boundaries, together with fictive humorous ones:

*The {{w|termination shock}} – the point in the heliosphere where the solar wind slows down to subsonic speed (relative to the star) because of interactions with the local interstellar medium.
*The {{w|heliopause}} – the theoretical boundary where the Sun’s solar wind is stopped by the interstellar medium.
*The {{w|heliosheath}} – the region of the heliosphere beyond the termination shock.
*{{w|Heliosphere}} – a region of space dominated by Earth’s Sun, a sort of bubble of charged particles in the space surrounding the Solar System.
*Heliodrome – yet another composition of ''helios'' "sun", here together with ''dromos'' "course". There is no astronomical object with this name, but it has been used variously in other contexts. One that became famout is a sports hall which was used as a concentration camp in the Bosnian war, see {{w|Heliodrom camp}}.
*Auroral discontinuity - another fictitious astronomic object, for ''auroral'' see {{w|Aurora (astronomy)}}.
*Heaviside layer – a layer of ionized gas occurring between roughly 90–150 km (56–93 mi) above the ground in the Earth's atmosphere.
*Trans-Neptunian panic zone – this fictional zone combines the word from two subject: “Trans–Neptunian” is used in astronomy to describe stuff that occurs beyond the planet Neptune. In {{w|Outdoor education}} the “panic zone” is the opposite of the {{w|comfort zone}} when trying to learn new stuff.
*{{w|Ignition magneto|Magnetogap}} – part of an {{w|ignition system}}.
*US Census Bureau Solar System statistical boundary – a fictive boundary defined by the {{w|United States Census Bureau}}, similarly to how it defines {{w|Census tract|census areas}} for the purpose of processing statistical data about regions in the United States.
*Kuiper gauntlet – this is a play on the {{w|Kuiper belt}}, which is region of the Solar System beyond the planets, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun, notable for being full of asteroids; replacing the word “belt” with “{{w|Gauntlet (glove)|gauntlet}}”, which is a tough glove used by sword fighters.
*Oort void – refers to the {{w|Oort cloud}}, a gigantic “cloud” of materials (mainly composed of ice) which ends around a light-year from The Sun and is deemed the (current) “edge” of the solar system.
*Crystal sphere holding the fixed stars – this refers to historical ideas about the universe, in which the stars were supposed to be fixed on a {{w|Celestial spheres|large crystal sphere}} around the Earth.

==Transcript==
:Number of times ''Voyager 1'' has left the Solar System
:[22 tally marks.]

{{comic discussion}}
[[Category:Physics]]
[[Category:Charts]]

1189: Voyager 1

2013-03-22T09:11:06Z

80.219.253.33: /* Explanation */ There is no "Oort void", it's the "Oort cloud".

{{comic
| number = 1189
| date = March 22, 2013
| title = Voyager 1
| image = voyager_1.png
| titletext = So far Voyager 1 has 'left the Solar System' by passing through the termination shock three times, the heliopause twice, and once each through the heliosheath, heliosphere, heliodrome, auroral discontinuity, Heaviside layer, trans-Neptunian panic zone, magnetogap, US Census Bureau Solar System statistical boundary, Kuiper gauntlet, Oort void, and crystal sphere holding the fixed stars.
}}

==Explanation==
''{{w|Voyager 1}}'' is a U.S. space probe launched in 1977 to study the outer reaches of the Solar System and beyond. Popular press has on several occasions announced that it “has left the solar system” – at each point when a boundary has been confirmed or a major event has taken place – the fact is that there is no strictly defined and recognizable boundary of the solar system.

The alt-text lists several such possible boundaries, together with fictive humorous ones:

*The {{w|termination shock}} – the point in the heliosphere where the solar wind slows down to subsonic speed (relative to the star) because of interactions with the local interstellar medium.
*The {{w|heliopause}} – the theoretical boundary where the Sun’s solar wind is stopped by the interstellar medium.
*The {{w|heliosheath}} – the region of the heliosphere beyond the termination shock.
*{{w|Heliosphere}} – a region of space dominated by Earth’s Sun, a sort of bubble of charged particles in the space surrounding the Solar System.
*Heliodrome – a {{w|Heliodrom camp|concentration camp}} from the Bosnian war.
*Auroral discontinuity.
*Heaviside layer – a layer of ionized gas occurring between roughly 90–150 km (56–93 mi) above the ground in the Earth's atmosphere.
*Trans-Neptunian panic zone – this fictional zone combines the word from two subject: “Trans–Neptunian” is used in astronomy to describe stuff that occurs beyond the planet Neptune. In {{w|Outdoor education}} the “panic zone” is the opposite of the {{w|comfort zone}} when trying to learn new stuff.
*{{w|Ignition magneto|Magnetogap}} – part of an {{w|ignition system}}.
*US Census Bureau Solar System statistical boundary – a fictive boundary defined by the {{w|United States Census Bureau}}, similarly to how it defines {{w|Census tract|census areas}} for the purpose of processing statistical data about regions in the United States.
*Kuiper gauntlet – this is a play on the {{w|Kupier belt}}, which is region of the Solar System beyond the planets, extending from the orbit of Neptune (at 30 AU) to approximately 50 AU from the Sun, notable for being full of asteroids; replacing the word “belt” with “{{w|Gauntlet (glove)|gauntlet}}”, which is a tough glove used by sword fighters.
*Oort void – refers to the {{w|Oort cloud}}, a gigantic “cloud” of materials (mainly composed of ice) which ends around a light-year from The Sun and is deemed the (current) “edge” of the solar system.
*Crystal sphere holding the fixed stars – this refers to historical ideas about the universe, in which the stars were supposed to be fixed on a {{w|Celestial spheres|large crystal sphere}} around the Earth.

==Transcript==
:Number of times ''Voyager 1'' has left the Solar System
:[22 tally marks.]

{{comic discussion}}
[[Category:Physics]]
[[Category:Charts]]

1187: Aspect Ratio

2013-03-19T19:55:34Z

80.219.253.33: /* Explanation */ We had one in the late 90s, and it was not unusual (at least here in Europe) for new TVs.

{{comic
| number = 1187
| date = March 18, 2013
| title = Aspect Ratio
| image = aspect ratio.png
| titletext = I'm always disappointed when 'Anamorphic Widescreen' doesn't refer to a widescreen Animorphs movie.
}}

==Explanation==
Aspect ratio is the relationship between the width and height of the image (and in this case, a video) and is denoted in a radio of <width>:<height> - usually either in lowest common denominator, or with a decimal width to a height of "1". Up until the 1990s, all televisions and most computer monitors (CRT tube and LCD) were in the standard 4:3 aspect ratio, called "fullscreen" (meaning the width is 4/3 or 1.33... times the height). When HDTV was developed, the standard for television screens changed to 16:9 (width being 16/9 or 1.77... times the height), called "widescreen" (although widescreen can also refer to a number of even wider ratios used in feature films). Computer monitors are now available in widescreen ratios, though fullscreen remains common as well.

Letterboxing is a process whereby an image which does not fully fill a screen is expanded to fill the screen by the addition of further material (mattews). Usually this is done with the addition of black bars in the empty space. One example of why this was necessary was widescreen films on VHS cassette. VHS could only record and play back 4:3 images. Thus, in order to display a widescreen film, the rest of the VHS's 4:3 image had to be filled with horizontal black bars at the top and bottom of the image. Those bars were part of the video information recorded on the cassette.

When DVDs were introduced, many DVDs also had letterbox bars on the DVD's full screen image. With the increased popularity of widescreen televisions, DVD players were improved to offer {{w|anamorphic widescreen}}, in which the full widescreen image is horizontally rescaled (shrunk) into a 4:3 size, which the player then was able to display stretched horizontally back to the proper widescreen aspect.

With the advent of Blu-Ray, video is generally encoded in whatever its proper aspect ratio is intended to be, and the player itself is left to appropriate matte the image.

The problem with letterboxed video (such as a 16:9 video letterboxed for 4:3) is that if one tries to watch the video on a 16:9 widescreen, where the image ''should'' fill the whole screen, instead the 4:3 letterboxed image fills part of the screen with further vertical mattes on the left and right of the image, thus producing an image with mattes on all four sizes which is much smaller than it needs to be. Some TVs or media players can zoom to help resolve the issue, although the video resolution usually suffers. By encoding only the video itself and allowing the player to do the matting, the video can be seen as large as possible on any given screen.

''{{w|Animorphs}}'' is a late-90's to early-00's young adult book series about shape-shifting teens who turn into animals to fight body-snatching aliens. Sony held the rights to create a film, but never made use of them, beyond creating URLs for a proposed movie on December 11th, 2012.

In this comic, Randall appears to be complaining about the issue of widescreen videos which have been rescaled to 4:3 by adding mattes to the top and bottom and uploaded on sites like YouTube. He is probably annoyed by the fact that on his widescreen monitor, TV or mobile device, the video (as noted above) does not fill the screen because of the letterboxing. In some cases, uploaders also take video and rescale it to the point where the image is improperly compressed horizontally or vertically, even without letterboxing. This is more akin to the car crushing Randall depicts in the comic.

==Transcript==
:[A car is crushed in a large black clamp.]
:Whenever someone uploads a letterboxed 16:9 video rescaled to 4:3, I do this to their car.

{{comic discussion}}