explain xkcd - User contributions [en]

Talk:2651: Air Gap

2022-07-29T00:31:57Z

108.162.250.188: Added note on signature

Worth noting that this is a large and inefficient version of an [https://en.wikipedia.org/wiki/Opto-isolator opto-isolator] [[Special:Contributions/108.162.221.79|108.162.221.79]] 05:37, 28 July 2022 (UTC)

: Incandescent light bulb (assuming it the lamp does not use LED in the shape of light bulb) is not only less efficient than diode, but also much slower to warm up and cool down - it usually is much more sensitive to rapid switching, and has shorter life counted in the number of on/off cycles. --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 07:45, 28 July 2022 (UTC)
:: There’s not even any indication that the bulb is shaped like an incandescent bulb. Only that the front of the light (either fixture or bulb) is a convex curve. For all we know that could be a lens or diffuser in front of a flat LED. Whoever wrote that needs to go back and walk, because the claim that an incandescent bulb is depicted is quite simply false.[[Special:Contributions/172.71.142.89|172.71.142.89]] 10:35, 28 July 2022 (UTC)

: I don't think it's less or more efficient than an opto-isolator, it essentially ''is'' just an opto-isolator. But an opto-isolator isn't supposed to be energy efficient to begin with; it's only designed to transmit data between circuits, not power. So the output side only needs to generate enough voltage/current to change the state of a transistor, and the input side only needs to generate enough light for the output side to do that. The voltages and currents involved aren't comparable to power circuits. --[[User:NeatNit|NeatNit]] ([[User talk:NeatNit|talk]]) 08:14, 28 July 2022 (UTC)

: By the way, wikipedia links can be written like this: <code><nowiki>[[wikipedia:opto-isolator|]]</nowiki></code> result: [[wikipedia:opto-isolator|opto-isolator]] (the final <code>|</code> automatically gets expanded to the article title without the <code>wikipedia:</code> prefix). --[[User:NeatNit|NeatNit]] ([[User talk:NeatNit|talk]]) 08:26, 28 July 2022 (UTC)
::Or more often here on ExplainXkcd, <code><nowiki>{{w|article}}</nowiki></code> or <code><nowiki>{{w|article|anchor text}}</nowiki></code>. [[Special:Contributions/172.70.206.213|172.70.206.213]] 08:35, 28 July 2022 (UTC)

::: Yes, thanks :) although there is a tiiiiiny advantage to the direct link without the template (the way I said), <code><nowiki>[[wikipedia:Pipe (computing)|]]</nowiki></code> becomes [[wikipedia:Pipe (computing)|Pipe]] whereas <code><nowiki>{{w|Pipe (computing)}}</nowiki></code> becomes {{w|Pipe (computing)}}. The pipe trick strips out the disambiguation parts of the title according to [[Wikipedia:Help:Pipe trick|some rules]]. --[[User:NeatNit|NeatNit]] ([[User talk:NeatNit|talk]]) 12:30, 28 July 2022 (UTC)
:::: Why not <code><nowiki>{{w|Pipe (computing)|pipe}}</nowiki></code>? [[Special:Contributions/172.70.214.95|172.70.214.95]] 15:18, 28 July 2022 (UTC)

It is missing that air-gapping the power supply would protect your home from voltage surges in the power network caused by lightning strikes. Depending where the lightning hits the power network, there may be no fuses protecting your home or single fuses may fail to protect you. --[[Special:Contributions/172.70.246.115|172.70.246.115]] 07:57, 28 July 2022 (UTC)
:That is true. But the suggestion that this might have anything to do with general energy security (as is currently very prominent in the explanation) is entirely unconvincing to me.
::I also originally thought this was the main joke, until seeing the title text about bit rate. Certainly it's worth mentioning, even if this isn't the main joke, since it would actually work, with a wide enough gap, ideally with a vacuum in between.

Incandescent light bulbs convert most of their energy to infrared light. There are solar cells that work in this infrared spectrum, so this might not be all that inefficient as stated. This should in fact be a lot more efficient than any LED+visible spectrum based panel, as incandescent bulbs are very efficient in converting electricity into infrared light, much more than LEDs most likely will ever be.
The (mostly) omnidirectionality of the light source might be an even bigger loss, as most of the light (however efficient) does not even reach the panel.
And regarding sending data over this construct: As soon as there's a 0V state (which will be the case as soon as the transmission starts, due to some form of manchester coding, regardless of it being a 0 or 1 bit) the PC behind the solar panel would not only have a data transmission problem :)
(With incandescent bulb, that is. A LED 0V might be short enough for capacitors in the PC's power supply to buffer it, if it is only at 50%(+PSU conversion loss) load max, as manchester coded signals per definition have a duty cycle of 50% to keep the DC bias at 0V)
[[Special:Contributions/172.68.51.204|172.68.51.204]] 08:26, 28 July 2022 (UTC)

What is the highest wattage commercial opto-isolator, and how can I get one mounted from the ceiling in my bedroom? [[Special:Contributions/172.70.207.8|172.70.207.8]] 14:10, 28 July 2022 (UTC)

I wonder if it's worth noting the significant understatement within the title text, where it says "the bitrate does drop a little" in contrast to the severe and drastic drop in bitrate that would actually occur, especially in light of today's typical Internet speeds. It might not be worth mentioning, but it struck me as a humorous understatement of the true impact. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 14:25, 28 July 2022 (UTC)
:We don't know if the light bulb is incandescent or LED, so we can't describe the bandwidth drop other than in very general terms. [[Special:Contributions/172.70.211.88|172.70.211.88]] 15:34, 28 July 2022 (UTC)

I'm almost tempted to suggest that this should be an (honourary) addition to the Cursed Connectors comic-collection. [[Special:Contributions/172.71.94.187|172.71.94.187]] 14:56, 28 July 2022 (UTC)

Yes, solar panels can transform electrical into electromagnetic signals. It is more on the side of the incandescent bulb that the capability to receive and forward these signals is missing. My source: https://www.youtube.com/watch?v=TGUteH93xNo
[[User:Torge|Torge]] ([[User talk:Torge|talk]]) 15:11, 28 July 2022 (UTC)

Nobody caught on that powerline networking is about sending data through powerlines? or that a crude opto-isolation setup could effectively scrub it? Where my networking geeks at? I am disappoint [[Special:Contributions/172.69.71.51|172.69.71.51]] 15:19, 28 July 2022 (UTC)

Electrical engineering here: perhaps we should mention that the box pictured after the solar panel must be an inverter? The lightbulb/solar panel pair will be acting as a rectifier, putting out purely positive voltage, and to get back to AC to run appliances on there would need to be an inverter.
(Not entirely sure how to appropriately sign this without creating an account, sorry)

2648: Chemicals

2022-07-21T05:31:34Z

108.162.250.188: Undo revision 289677 by 108.162.245.249 (talk)

{{comic
| number = 2648
| date = July 20, 2022
| title = Chemicals
| image = chemicals.png
| titletext = It's hard to believe, but lots of kids these days ONLY know how to buy prepackaged molecules.
}}

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

In this comic, [[Megan]] mentions that her company spends a lot on chemicals for which you can find formulas online. She suggests assembling chemicals from atoms "bought in bulk," holding a sheet of paper with the {{w|empirical formula}} C5H6NO2 which designates [https://pubchem.ncbi.nlm.nih.gov/#query=C5H6NO2 more than a hundred compounds and ions], including {{w|nitrobenzene}}, {{w|niacin}}, {{w|isonicotinic acid}}, and {{w|picolinic acid}}, followed by their component elements listed with prices. The ambiguity of chemical formulae is one of the jokes in the comic.

While in-house {{w|chemical synthesis}} is sometimes cost effective, usually it is not, because end users are often unable to leverage the {{w|economies of scale}} inherent in bulk manufacturing by specialist industrial firms.[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880393/] However, we don't know whether Megan and [[Cueball]] work in a laboratory, factory, or some other industrial setting. In-house chemical syntheses in factories using large volumes often ''are'' cost-effective, as can be laboratory syntheses of very small quantities.

In any case, producing chemicals from their constituent elements or {{w|Precursor (chemistry)|precursor compound}}s is difficult, time-consuming, requires expensive equipment, and is often fraught with peril.[https://www.youtube.com/watch?v=5QwW2owNWgc] Nitrobenzene, one of the C5H6NO2 compounds, is an excellent example because it is explosive, extremely toxic, and its synthesis is highly exothermic, making it one of the most dangerous syntheses in the chemical industry.[https://www.icheme.org/media/10339/xiii-paper-36.pdf] Such issues answer Cueball's question as to why more places don't manufacture their own chemicals. The characters' naivety also gives rise to the humor of the comic, which may also be mocking DIY lifehacks where the cost savings only make sense if their massive time investment is ignored. "Big Molecule" is an [[2130: Industry Nicknames|industry nickname like Big Oil or Big Pharma]], and amusing in its own right.

The title text refers to the fact that many people believe that "kids these days" don't do enough work or are spoiled. Randall has expressed that he dislikes statements like these in [[2165: Millennials|previous comics]].

This comic may have been prompted by recent news that [https://english.elpais.com/science-tech/2022-07-15/for-the-first-time-in-history-we-can-modify-atomic-bonds-in-a-single-molecule.html scientists have found a way to assemble and change atoms in individual molecules] by modifying their bonds.

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

:[Megan and Cueball standing next to each other. Megan has her palms raised.]
:Megan: You know how our company spends a lot on expensive chemicals?
:Cueball: Yeah?

:[Megan holding up a piece of paper with a chemical formula on it, as well as some computation for the number of atoms needed]
:Megan: Well, I just learned you can look up all of the formulas online!
:Megan: We can just buy the atoms in bulk and assemble them here!
:[The paper reads as follows. The illegible items appear to be prices.]
:C6H5NO2
:Carbon 6 $[illegible]
:Hydrogen 5 $[illegible]
:Nitrogen 1 $[illegible]
:Oxygen 2 $[illegible]
:Total 14 $[illegible]

:[Cueball still standing. Megan walking off-panel to the right]
:Cueball: I wonder why more places don't do that.
:Megan: People have no idea they're getting ripped off by Big Molecule!

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Chemistry]]

2625: Field Topology

2022-05-30T02:32:26Z

108.162.250.188: /* Transcript */

{{comic
| number = 2625
| date = May 27, 2022
| title = Field Topology
| image = field_topology.png
| titletext = The combination croquet set/10-lane pool can also be used for some varieties of foosball and Skee-Ball.
}}

==Explanation==
{{incomplete|Created by A DONUT, OR WAS IT A COFFEE MUG? Please check the new first paragraph, especially the end. And maybe move the mathematical fields/Fields Medal diversion to a footnote. Do NOT delete this tag too soon.}}

Field Topology is [https://encyclopediaofmath.org/wiki/Topological_field a subject in mathematics], but in this comic, Randall is instead examining the topology of playing fields used for various recreational activities. The comic strip depicts a situation where the common practice of multi-use athletic facilities has been organized by the "topology department" and constructed to be shared by all sports whose normal playing fields are {{w|topology|topologically equivalent}}. However, one key assumption in topology is that you can ignore the specificities of shape, size and material of the objects concerned. This presents an amusing contrast with the actual activities listed in the comic, where the size and shape of hoops, nets and bars and the material of the field itself can be very significant [citation needed].

(Not to be confused with {{w|Field (mathematics)|mathematical fields}}, or the {{w|Fields Medal}} prize -- although successfully {{w|Straightedge and compass construction|constructing}} these fields might lead to medals of one kind or another being granted).

In topology, shapes which can be smoothly deformed into one another without adding or removing holes are considered to be "equivalent". Note that a topological hole is an area of the nominal space (or area, or other manifold) through which nothing restricted to this topology can pass. In describing a real-world archway, for example, this would be where the material of the arch is, not the actual 'hole' passing ''through'' the constructed arch, which is the path that one indeed may (or must!) pass through to get from one region of the layout to another. A loop is a path across the allowable territory of a topology (or a viable circuit to make through the world it describes) that end up where it started. If a loop cannot be tightened (ultimately adjusted to take a shorter path) down to a single point, then it must be wrapped around at least one 'topological hole' (i.e. through a physical one), and you have separately unique paths (or points, i.e. on different disconnected topologies) where you cannot adjust one loop to take the route of another, without severing a looped-path and reconnecting it.

{{w|Baseball}}, and {{w|tetherball}} are played on fields without any holes that the ball or players can completely pass through, so they are ({{w|Group (mathematics)|grouped}}) (physically and mathmatically) into one continuous field without holes. The goals on a {{w|soccer}} field presumably do not create holes because the goalposts and crossbar are connected to the field by the net, so the goals and field are topologically equivalent to a smooth disc. Any path taken into and out of the goal (any number of times) is topologically equivalent to one that does not go into this pocket of space at all.

{{w|Volleyball}} and {{w|badminton}} are played on a court through the center of which passes a net suspended from poles, and the {{w|high jump}} has a bar that contestants jump over. The space bounded by the bottom of the net (or bar), the supporting poles, and the ground can be considered to be a hole, a path over and under the net/bar cannot be simplified to one that does not, so their fields all have one "hole".

A basketball court has two physical pathable holes, the nets. Parallel bars can be thought of as two rectangles and thus as two topographical "holes". Both have opportunities to path through either (or both) structures, and so the material of the structures define a hole in the topological abstract of the playing 'surface'. Since we are told that these sports fields belong to the Topology Department - and are not necessarily generalized to all sports fields - we may safely assume that their "football" field is for "American football" and uses the older H-shaped football goals rather than the more modern Y-shaped ones. An "H" shaped goal creates a topological hole under the crossbar at both ends of the field. A more modern football field with Y-shaped goals would have no holes.

The lane dividers in a swimming pool create bounded holes on the 'playing surface' equivalent to one less than the number of lanes. And each hoop in croquet is a hole with one edge bounded by the playing surface. Similarly, as mentioned in the title text, this configuration is also {{w|homeomorphism|homeomorphic}} to a {{w|foosball}} table (with each rod sustaining the player figures above the table defining a hole) or a {{w|Skee-Ball}} lane (which is even more straightforward, as it is just a plane with several holes in which to throw balls).

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

A row of four signs, each held up by two posts, followed by a row of four rounded lozenge shapes, one for each sign. The signs and lozenge shapes are shaded as if three-dimensional objects, all being flattish with a small third dimension; the four lozenge shapes each have one pair of sides horizontal and the other pair at a slight angle from vertical, denoting a horizontal plane perpendicular to the signs extending "out" towards the viewer, which places each shape "in front" of its sign. All but the first lozenge shape have various numbers of ellipses within the shape - ovoids shaded to denote holes piercing through the objects.

Leftmost sign: "Baseball. Soccer. Tetherball." The shape below this sign contains no ellipses.

Second sign from left: "Volleyball. Badminton. High jump." This shape has one large ellipsis in the centre.

Third sign: "Basketball. Football. Parallel bars." This shape has two large ellipses - one in the top half and one in the bottom half.

Fourth and rightmost sign: "Olympic swimming. Croquet." This shape has nine small ellipses - eight arranged symmetrically towards the edges of the shape and one in the centre.

Caption underneath the signs and shapes: No one ever wants to use the topology department's athletic fields.

{{comic discussion}}
[[Category:Math]]
[[Category:Sport]]

Talk:1562: I in Team

2015-08-11T09:32:05Z

108.162.250.188:

There is no I in team, but there is an M and an E.[[Special:Contributions/162.158.56.215|162.158.56.215]] 08:26, 10 August 2015 (UTC)
: Ha, yes -- but they are backwards [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]]) 15:37, 10 August 2015 (UTC)

Check it out! there's "l" in "vowels"! --[[Special:Contributions/141.101.89.222|141.101.89.222]] 08:51, 10 August 2015 (UTC)

<sarcasm>There is an (annagram of) Randal in "People who don't understand how a proverb works" </sarcasm> No, seriously this is just cueball being a smart-ass. --[[Special:Contributions/162.158.91.230|162.158.91.230]] 08:53, 10 August 2015 (UTC)

There's no I in team, but there is an I in pie; there's an I in meat pie and meat is an anagram of team, so... {{unsigned ip|141.101.99.82}}

:There's a 999999 in pi. {{unsigned ip|198.41.239.32}}

:: Doesn't pi contain every possible number sequence though? [[Special:Contributions/162.158.91.235|162.158.91.235]] 11:17, 10 August 2015 (UTC)

::: No. There is no evidence that pi includes an offset of pi.
:::There is no I in team, but there is meat... blessed meat :::Simpson drool:: {{unsigned|Cwallenpoole}}

:::: ''finite'' sequence. the kate bush conjecture is unproven. {{unsigned ip|141.101.98.34}}

The arbitrariness of this saying was demonstrated considerably more elegantly in Jeffrey Rowland's Wigu: "There is no I in 'team', but there is in 'family'." [[Special:Contributions/198.41.242.93|198.41.242.93]] 11:56, 10 August 2015 (UTC)

This joke is not self-referential, it's metalingual. See https://en.wikipedia.org/wiki/Jakobson%27s_functions_of_language [[User:Xhfz|Xhfz]] ([[User talk:Xhfz|talk]]) 13:10, 10 August 2015 (UTC)

[http://rlv.zcache.com/i_in_team_there_it_is_hidden_in_the_a_hole_tshirt-r0aff1796c915419aaa4c3f9c73794dcf_f0yq2_1024.jpg There is]. --[[Special:Contributions/141.101.98.185|141.101.98.185]] 16:18, 10 August 2015 (UTC)

: That's deep. --[[Special:Contributions/108.162.229.188|108.162.229.188]] 18:05, 10 August 2015 (UTC)

It is interesting that Randall worded Cueball's dialogue as "There is a 'U' in People who apparently don't understand...". There is just that one 'U', in "understand". If he'd said instead something like "There is a 'U' in People who apparently don't get...", the reference to Hairy through 'U'/you would've been entirely allusional!
- Vik [[Special:Contributions/108.162.225.76|108.162.225.76]] 19:30, 10 August 2015 (UTC)

This comment is my way of noting and speculating that it makes sense that the origin of "No I in Team" is from baseball pitchers: They're the only team sport player I know of who is regularly replaced mid-game for reasons besides injury. If a pitcher thinks he's on a hot streak, but the coach replaces him because reasons, a phrase like like "No I in Team" may be needed to smooth over the resulting disagreement, regardless of whether the coach or the pitcher has their respective heads up their asses or not. [[Special:Contributions/199.27.133.53|199.27.133.53]] 20:05, 10 August 2015 (UTC)

But there IS an I in team! http://i.imgur.com/prPC7BX.jpg [[Special:Contributions/141.101.85.151|141.101.85.151]] 02:16, 11 August 2015 (UTC)

I think it's interesting that there is exactly one "u" in "People who apparently don't understand the relationship between orthography and meaning", which has 76 letters. "U" isn't a terribly infrequent letter. [[Special:Contributions/108.162.221.133|108.162.221.133]] 04:42, 11 August 2015 (UTC)

I think part of the joke that is missed in the current explanation is that cueball is responding with a less vulgar version of the common retort: "But there is a 'U' in c*nt."[[Special:Contributions/108.162.250.188|108.162.250.188]] 09:32, 11 August 2015 (UTC)

1446: Landing

2015-07-08T14:34:29Z

108.162.250.188: /* Explanation */

{{comic
| number = 1446
| date = November 12, 2014
| title = Landing
| image = landingAnimated.gif
| titletext = [LIVE]
}}
Frames of the comic began appearing at midnight ({{w|Eastern Time Zone|EST}}) on November 12, 2014 and updated every five minutes. Together, the images form a {{w|flip book}} which is shown here above. You can find the individual images by clicking on the latest image of the comic on xkcd (go to that by clicking the date above or find it directly at [http://xkcd1446.org xkcd1446.org]).

==Explanation==
{{incomplete|The comic has been updated further since Philae was awakened}}
This comic changed over time during 12 hours and 15 minutes starting at 0:00 EST (when the comic normally is released) posting 143 pictures that tracked the progress of the {{w|Philae (spacecraft)|Philae}} lander separating from the {{w|European Space Agency}}'s {{w|Rosetta (spacecraft)|Rosetta}} probe to land on comet {{w|67P/Churyumov–Gerasimenko}}. More info can be found here: [http://rosetta.esa.int rosetta.esa.int].

The comic presents the imagined anthropomorphic "thoughts" of the Rosetta spacecraft and the Philae lander (and occasionally other parties) during the hours approaching separation from each other, approach to the comet and finally the apparently successful landing on the comet.

Beginning at [[Media:???65.png|11:05]], the comic includes a '''"Status Report"''' in the lower right corner which summarizes the status of various interested parties and accomplishments, beginning with "Rosetta", "Philae lander", "Mission Control", "Comet 67P", and "Have we landed on a comet?". As events occur in the comic, more status summaries are added to keep track of the changes to the situation and the supposed emotions behind them.

In many pictures a whale can be seen on the surface of the comet - often marked with a "?" as are almost all other parts of the unknown surface at this time. There is also drawn a [[Cueball]] on the surface also marked with a "?" Both are then at some point marked with a ''probably not'' - starting from [[Media:???83.png|12:35]]. The whales are also mentioned in the "Status Report" where they for instance may be listed as "calm" or "(probably) not in space". At [[Media:???122.png|16:00]] the when the entire Earth goes ''AAAAAAAAAAA'' the whales are listed as saying this as well (along with Mission control and U.S. scientists). From this moment "Dolphins and fish" are also mentioned in the report. They are asking if it is the whales that scream. The reference to whales comes from the fact that Philae brought along two harpoons that should have been used to anchor it to the comet. On Earth, harpoons have mainly been used to hunt whales; Randall previously brought up that comparison in [[1402: Harpoons]], suggesting that Philae was programmed to believe it was sent to kill the comet. It is Philae that "dreams" about whales on the surface of the comet which can be seen in the picture for [[Media:???93.png|13:25]] and in the status report.

Some {{w|Douglas Adams}} fans believe these whales and dolphins are references to ''{{w|The Hitchhiker's Guide to the Galaxy}}'' and ''{{w|So Long, and Thanks for All the Fish}}.'' Whales in space have been appearing in fiction and art since the 1960s. However, with the above mentioned reasons for whales, dolphins and fish, this seems less and less likely.

Shortly after release from Rosetta ([[Media:???56.png|10:15]]), Philae calls out 'Spaaaaaaaaaace'; this mimics the {{w|Portal 2}} 'Space core' who, on finally reaching space in the last scenes, gives the same elated cry.

US Scientists presumably wake up at 7:40 EST ([[Media:???96.png|13:40]] UTC) and in the report they now says "Bluuurghhh. What time is it?" to indicate their tiredness. This does not change until 10:25 EST ([[Media:???115.png|15:25]] UTC) so they are slow to wake (2 hours 45 minutes). At this point, they becomes anxious as there are only 10 minutes to landing. This last until there is 15 minutes until news of landing (a reference to the 28 minutes time delay due to the huge distance to the comet). From then on ([[Media:???120.png|15:50]]) they and the mission control (MC) say "AAAAAAA". They stop this when the news should be there - the NOW ([[Media:???122a.png|16:05]]) - and everybody holds their breath indicated by [...] - also MC. Finally ([[Media:???125.png|16:25]]) they and MC become proud (along with Earth) when Philae announces ''I got you a comet.'' It should have stopped there but as Philae bounced around, they then becomes anxious again [[Media:???128.png|16:40]], and then this changes to nervous [[Media:???129.png|16:45]] (switching those emotions with MC). And then suddenly ([[Media:???130.png|16:50]]) it is no longer US Scientists but just plain Scientists - that are nervous. It stays like this during the last few pictures, although they again become anxious, but when Philae announces ''I did it'', they drink wine as indicated with "[wine]" in the report from the second to last picture ([[Media:???134.png|17:10]]).

Randall has written "A big thank-you to [https://twitter.com/elakdawalla Emily Lakdawalla] for help and advice on this comic" in the xkcd page header for [http://www.xkcd.com/1446/ Landing], revealing the possible source of his near real-time data.

At [[Media:???124.png|16:20]] the status report had announced a big '''Yes''' to the questions "Have we landed on a comet" and "Do harpoons work on comets". According to [http://www.bbc.com/news/science-environment-30026398 BBC News], the harpoons did, however, not fire as planned and the lander may have landed, bounced off, and landed again. This would explain the change in "Do harpoons work on comets" to "Don't know" at [[Media:???127.png|16:35]] and the change in "Have we landed on a comet?" to "Yes, at least once" at [[Media:???130.png|16:50]]. According to [http://www.nytimes.com/2014/11/13/science/space/european-space-agencys-spacecraft-lands-on-comets-surface.html?_r=0 The New York Times], radio contact with Philae fluctuated, which would explain the "Anxious", "Nervous", and "Confused" statuses around that time. In the end the lander did land and whereas the Do harppons work status did not change, so did the have we landed on a comet which changed back to '''Yes''' at [[Media:???134.png|17:10]].

The lander bounced three times and ended up in a place where the solar panels where mainly in the shadow. This resulted in the lander shutting down when its own battery ran out of power after only 2-3 days on the ground. This seemed sad, as there was only a small chance that the seasons on the comet would change so that the panels would later receive sun again. However, in the few hours that Philae had on the ground, it still managed to analyze the surface and obtain a lot of useful data - so that part of the mission was still a success already. This all happened after the comic stopped updating.

On June 13, 2015, it was announced that signals had been received on earth indicating that Philae had awoken and that the solar panels were functioning. Ironically, had Philae landed in a place originally out of shadow, it would have already failed before this time (due to overheating), so it was actually fortunate that it landed as it did and would be able to operate during the time that the comet would be closer to the sun. To celebrate the lander's revival, Randall updated the comic, depicting the lander saying "Hi." on the comet's surface.

The comic title was originally "???" (probably to not give away too early what the comic was about), but changed to "Landing" when Randall came on live at five in the morning EST. At that moment the title text also changed from "..." to "[LIVE]". It was also then that the timestamps' timezone switch. At 5:00 AM (EST) the time stamp in the picture naming scheme switched from EST to {{w|Coordinated Universal Time|UTC}} as used in ESA's time keeping, resulting in a jump from [[Media:???53.png|04:55]] to [[Media:???54.png|10:00]] without actually any such delay between the two pictures.

There were however a few pictures with more than 5 minutes of delay (about 11 times five minutes without an update in total during the "live" transmission). The update seemed to have stopped after 137 pictures at 17:15 UTC, 12 hours and 15 minutes after the first picture. (The first picture has number 0, so the last had number 136). But later, sometime after 17:15 UTC, the counter for the last picture was increased to 142 (143 pictures in total), so maybe Randall inserted 6 extra pictures later - however he must then have changed the numbers on the pictures, since the last picture remained the same until mid-June, but with number 142 instead of 136. It is thus now difficult to find out which pictures would have been added later. However, eight pictures were not included in the original table with the [[#Frame by Frame Breakdown|Frame by Frame Breakdown]] below. So it must have been some of those missing pictures that were added later - maybe all of them, as the last three may already have been added before the last picture was released (All 143 pictures are included in the flip-book gif image shown here above). But even 143 pictures at 5 minutes intervals only spans 11 hours and 50 minutes, thus there are still five ''5 minute intervals'' without any picture. See which in the [[1446: Landing/Frame by Frame Breakdown|table]].

==Frame by Frame Breakdown==
*Here is a [[1446: Landing/Frame by Frame Breakdown|link to a table]] with a frame by frame breakdown of all 143 pictures.
*Here is a [[1446: Landing/All pictures|page with all the pictures]] frame by frame.

==Transcript==
:[This transcript gives only the text in the last of the 143 pictures shown in the comic. That which is now shown when clicking to the comic on xkcd.]

:[This is the from the picture with time stamp 17:15.]
:[Showing Philae on a comet.]
:Rosetta: Philae?
:Rosetta: Is everything OK?
:Philae: I landed!
:Philae: I'm on a comet.
:Philae: I'm OK and I'm on a comet.
:[Status report at the bottom-right corner.]
:Status report:
::Rosetta: In space
::Philae lander: Landed
::Mission control: !!!!!
::Comet 67P: Landed on
::Whales: Calm
::Scientists: [Wine]
::Harpoons: Tricky
::Dolphins and Fish: OK
::Have we landed on a comet?: '''YES'''
::Do harpoons work on comets: Don't know
::Earth: !!!!!
::Has anybody tried this before: Nope

:[For the '''full transcript''' of all 143 pictures see '''[[1446: Landing/Transcript]]'''.]

==Trivia==
*There appears to be a brief error between 02:35 and 02:45, where the time until lander separation is shown as 1 hour, counting down to 50 minutes, before being corrected to 75 minutes at 02:50.
**Since this was supposed to be during the "non-live" section before Randall got up (and got live) it is not sure whether this was a "real" mistake, or if he was up anyway, and corrected this timing error when he discovered the plans had change during the approach flight.

{{comic discussion}}
[[Category:Dynamic comics]]
[[Category:Space]]
[[Category:Comics with color‏‎]]
[[Category:Comics featuring Cueball‏‎]]
[[Category:Animals‏‎]]

1508: Operating Systems

2015-04-06T06:08:09Z

108.162.250.188: /* Explanation */

{{comic
| number = 1508
| date = April 6, 2015
| title = Operating Systems
| image = operating systems.png
| titletext = One of the survivors, poking around in the ruins with the point of a spear, uncovers a singed photo of Richard Stallman. They stare in silence. "This," one of them finally says, "This is a man who BELIEVED in something."
}}

==Explanation==
{{incomplete}}

In this comic, Randall provides a timeline of the use of different operating systems in his house.

The title text refers to Richard Stallman, the founder of the [http://www.fsf.org/about Free Software movement] and the [https://www.gnu.org/gnu/gnu.html GNU project], and refers to the timeline when GNU/Hurd is the only Operating System having survived the apocalypse.

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

1508: Operating Systems

2015-04-06T06:06:07Z

108.162.250.188: /* Explanation */

{{comic
| number = 1508
| date = April 6, 2015
| title = Operating Systems
| image = operating systems.png
| titletext = One of the survivors, poking around in the ruins with the point of a spear, uncovers a singed photo of Richard Stallman. They stare in silence. "This," one of them finally says, "This is a man who BELIEVED in something."
}}

==Explanation==
{{incomplete}}

In this comic, Randall provides a timeline of the use of different operating systems in his house.

The title text refers to Richard Stallman, the founder of the Free Software movement and the GNU project, and refers to the timeline when GNU/Hurd is the only Operating System having survived the apocalypse.

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

1508: Operating Systems

2015-04-06T06:04:04Z

108.162.250.188: /* Explanation */

{{comic
| number = 1508
| date = April 6, 2015
| title = Operating Systems
| image = operating systems.png
| titletext = One of the survivors, poking around in the ruins with the point of a spear, uncovers a singed photo of Richard Stallman. They stare in silence. "This," one of them finally says, "This is a man who BELIEVED in something."
}}

==Explanation==
{{incomplete}}

In this comic, Randall provides a timeline of the use of different operating systems in his house.

The title text refers to Richard Stallman, the founder of the Free Software movement and the GNU project.

==Transcript==
{{incomplete transcript}}

{{comic discussion}}