explain xkcd - User contributions [en]

1467: Email

2015-01-05T01:13:38Z

108.162.250.231: /* Explanation */

{{comic
| number = 1467
| date = December 31, 2014
| title = Email
| image = email.png
| titletext = My New Year's resolution for 2014-54-12/30/14 Dec:12:1420001642 is to learn these stupid time formatting strings.
}}

==Explanation==
Despite being in popular use since 1998 when free email providers appeared and having existed since before 1982 when {{w|SMTP}} was established, [[Beret Guy]] apparently doesn't understand what {{w|email}} is, even though he maintains a web page that includes his email address. [[Megan]] wonders how else he expects electronic messages to be sent. She explains that one must check email regularly, making a slight at {{w|voicemail}}, which she implies is not worth ever checking.

Beret Guy offers two alternatives: {{w|Fax}} and {{w|Snapchat}}. Megan refers to Snapchat as "the naked pic thing", calling to mind how many of its users send naked pictures of themselves over the Internet. Beret Guy replies that people use fax machines for more than just "faxting" (a made-up term similar to {{w|sexting}}), implying that many people send sexual content via fax, a technology that predates SMTP by more than a decade.

The title text, which could be [[Randall]]'s New Year's resolution for 2015, refers to various date/time formats. In programming, a point in time (eg. the current system time) is usually stored and processed as a single number that represents the count of seconds that have elapsed since a given starting time known as "epoch" (the Unix standard epoch is January 1, 1970 at midnight, {{w|UTC}}). In order to make sense to people, this number must be converted to a human-readable format, but programmers must choose a format that best meets the needs of their users. This can be a complicated problem to solve, given that there are many different standard formats for different regions, different levels of precision for different applications, and differences between "universal time" and a user's local time zone. Randall has previously advocated for widespread adoption of the [[1179: ISO 8601|ISO 8601]] format as a universal standard.

The title text also probably references a twitter outage that took place on December 29th, which was blamed on an [http://www.theguardian.com/technology/2014/dec/29/twitter-2015-date-bug error in a date format string].

Most programming languages provide functions to create a custom date-format string using "tokens" that represent different parts of the date/time. Here, Randall appears to have used one of these functions with the string "%Y-%M-%D %h:%m:%s", which looks like it should produce a date and time as "Year-Month-Day Hour:Minute:Second". However, he used the wrong tokens for this:

*%Y = 4-digit year (2014)
*%M = minute (54)
*%D expands to %m/%d/%y, which is "month/day/2-digit year" in the user's local time zone rather than UTC. ("12/30/14" - see below)
*%h = abbreviated month name ("Dec")
*%m = 2-digit month (12)
*%s = Unix timestamp (1420001642 seconds since epoch)

The "%s" token shows us the actual {{w|Unix time|Unix timestamp}} used (1420001642), which corresponds to 2014-12-31 at 04:54:02 UTC. The format string shown above thus yields "2014-54-12/30/14 Dec:12:1420001642". Note that the middle portion of this string shows "12/30" instead of "12/31" - this is due to the %D token expressing the date in Randall's local time zone, which is evidently at least 5 hours off from UTC. In Pacific Standard Time, for example, the time was 20:54:02, or just before 9:00 PM, on the previous day.

The correct format string for Randall's apparent desired result is "%Y-%m-%d %H:%M:%S", which gives the string "2014-12-31 04:54:02" (UTC) or "2014-12-30 21:54:02" (Pacific Time). Given the similarity between Randall's string and the correct one, it is easy to see how this type of formatting is confusing and often frustrating for programmers - particularly those not intimately familiar with these functions.

Randall previously addressed date/time formatting in [[1179: ISO 8601]] and [[1340: Unique Date]] (the latter of which uses a formatting string correctly).

==Transcript==
:[Megan approaches Beret Guy.]
:Megan: Any New Year's resolutions?
:Beret Guy: Gonna figure out what email is.
:Megan: ''...Email?''

:[Megan points to her phone.]
:Beret Guy: People always say they're sending them. They sound really into it, so I always nod, but I have no idea what it is.
:Megan: You have an address on your website!

:[Megan and Beret Guy walking.]
:Beret Guy: Oh, ''that's'' what that thing is.
:Megan: Email is important! You can't just ''never'' check it. It's not like voicemail.

:Beret Guy: Can't they just send messages ''normally?''
:Megan: How?
:Beret Guy: Fax! Or Snapchat.
:Megan: ...The naked pic thing?
:Beret Guy: Fax machines aren't ''just'' for faxting!

==Trivia==
The Unix timestamp is a standard method of describing the absolute number of seconds that have elapsed since "epoch", defined as midnight on January 1, 1970, Coordinated Universal Time (UTC). Epoch, in {{w|ISO-8601}} format, is "1970-01-01T00:00:00Z", where Z indicates UTC.

The timestamp in this comic's title text (1420001642) is 1,420,001,642 seconds since epoch. To convert that into a human-readable time:

*Years since 1970 = 1,420,001,642 seconds / 60 seconds per minute / 60 minutes per hour / 24 hours per day / 365.25 days per year
**This yields 44 years plus 31,467,242 seconds.
**The year for the timestamp is 1970 + 44 years = '''2014'''.
***Note: The year calculation specifies 365.25 days per year to account for {{w|leap year|leap years}} (every fourth year adds an extra day).
*Days since start of year = 31,467,242 seconds / 60 seconds per minute / 60 minutes per hour / 24 hours per day
**This yields 364 days plus 17,642 seconds.
**The 365th day of a non-leap year is '''December 31'''. December is the '''12th month''' in the Gregorian calendar.
*The remaining seconds can be converted into a time:
**Hours since start of day = 17,642 seconds / 60 seconds per minute / 60 minutes per hour = '''4 hours''' plus 3,242 seconds
**Minutes since start of hour = 3,242 seconds / 60 seconds per minute = '''54 minutes''' plus '''2 seconds'''

Thus, Randall's timestamp represents the time "'''2014-12-31'''T'''04:54:02'''Z" (again in ISO-8601 format).

{{comic discussion}}
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Megan]]

1411: Loop

2014-08-22T05:44:58Z

108.162.250.231: /* Explanation */

{{comic
| number = 1411
| date = August 22, 2014
| title = Loop
| image = loop.png
| titletext = Ugh, today's kids are forgetting the old-fashioned art of absentmindedly reading the same half-page of a book over and over and then letting your attention wander and picking up another book.
}}

==Explanation==
{{incomplete|Early-Bird Draft. Temporary synopsis. Reorganization and details reccommended.}}

Cueball is seen at his desk in front of four devices. He has clearly run out of things to do, or is looking for an excuse to procrastinate. A flowchart describes the process by which he scans the whole environment for something to do, which everyone can relate to.
The comic uses electronics likely because they are the common timekiller these days, and are most likely to contain fresh, tantalising entertainment.
News sites can be viewed as a good source of yet-to-be-seen content. Yet the search yields no interesting content, or the results don't garner enough attention, thus the blank stares and moving on to next device in line.

The title text notes that this probably still happened before there were electronics and the internet, when most entertainment came from books.

==Transcript==
:[Cueball sits at a desk, accompanied by numerous electronics - a desktop computer, a laptop, a tablet, and a smartphone.]
Diagram Text: "Stare blankly at screen -> open news site -> start reading -> get bored -> absentmindedly check smaller device

{{comic discussion}}

Talk:1407: Worst Hurricane

2014-08-13T08:03:59Z

108.162.250.231:

I tried to list all the unnamed hurricanes, but I gave up after 1938. Anybody feel like finishing it? [[Special:Contributions/108.162.219.195|108.162.219.195]] 05:37, 13 August 2014 (UTC)

The current explanation seems to interpret the title text completely wrongly; it isn't about finding a person that lived in *all* of the states, but finding people that lived in *each*. The point is that the entire data is estimated based on rainfall, not based on actually asking people the question.

1143: Location

2014-05-28T07:48:05Z

108.162.250.231: /* Transcript */

{{comic
| number = 1143
| date = December 5, 2012
| title = Location
| image = location.png
| titletext = Ingress: Foursquare With Space Noises.
}}

==Explanation==
{{w|Ingress (game)|Ingress}} is an {{w|augmented reality}} location-based service game in which players have to visit certain real-world places marked by the game as containing in-game objectives, called portals. The friend in the comic owns a home surrounded by an abundance of portals, which makes it an attractive destination for [[Cueball]] and co.

{{w|Foursquare}} is another service that lets users check into places they visit for discounts in a similar way to how Ingress players visit portals for points. "Space noises" refers to the ambient sounds when playing Ingress.

==Transcript==
:[A group of people around a computer. Cueball is typing.]
:Cueball: Hey, party tonight?
:Cueball: We'd all like to come see your new place!
:Friend (through monitor): Wait, what?

:[Cut to friend sitting at a laptop.]
:Cueball: We want to hang out!
:Friend: We're not, like, good friends.
:Cueball: I know, but we were thinking about it and we really like you!

:[Cut back to Cueball and friends.]
:Cueball: You should have us over tonight!
:Cueball: For, like, an hour.
:Cueball: It'll be fun!
:Friend: Well, uh, sure.

:[Cut to colour-inverted image of friend's house. Enlightened-controlled Ingress portals are surrounding the house.]
:Cueball: ''YESSSS!''
:Friend: I still don't get why you're suddenly so excited to hang out.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics with color]]
[[Category:Video games]]

1363: xkcd Phone

2014-05-02T05:45:46Z

108.162.250.231: speed of light is not 3m/s

{{comic
| number = 1363
| date = May 2, 2014
| title = xkcd Phone
| image = xkcd_phone.png
| titletext = Presented in partnership with Qualcomm, Craigslist, Whirlpool, Hostess, LifeStyles, and the US Chamber of Commerce. Manufactured on equipment which also processes peanuts. Price includes 2-year Knicks contract. Phone may extinguish nearby birthday candles. If phone ships with Siri, return immediately; do not speak to her and ignore any instructions she gives. Do not remove lead casing. Phone may attract/trap insects; this is normal. Volume adjustable (requires root). If you experience sudden tingling, nausea, or vomiting, perform a factory reset immediately. Do not submerge in water; phone will drown. Exterior may be frictionless. Prolonged use can cause mood swings, short-term memory loss, and seizures. Avert eyes while replacing battery. Under certain circumstances, wireless transmitter may control God.
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page.}}

This comic is a parody of a multitude of mobile-technology related issues that, when brought together, create a general satire of smartphone advertising. The advertised features here either make previously useful capabilities useless or add features nobody wants.

From bottom left, going clockwise:

Flightaware partnership - This is a parody of flight mode, a capability most smart phones have. When activated, flight mode disables all transmission and receiving capabilities, making the phone suitable for use while on commercial flights. Flightaware partnership, by contrast, is an intrusive presumably airline-sponsored capability that no one wants.

Realistic case– possibly a joke on various audiovisual devices like gaming consoles that advertise realistic sound, graphics, etc. Of course, applying "realistic" to an actual physical case is ridiculous. Either the case is actually real, or it doesn't actually function as a case.

Clear screen– This is a pointless descriptor from the perspective of the consumer. Of course the screen is clear. This joke works in tandem with the previous joke, as a play on "clear case, realistic screen," which are both hypothetically viable selling points.

Side Facing Camera – There was a recent controversy surrounding a kickstarter for a surreptitious, side-mounted camera device for smartphones due to the advertisement of the device as a good way to take creep shots, which are illegal in many places. Widespread dissemination of these devices as a built in would likely result in a sharp increase in delinquency of this nature.

Custom blend OS – iOS and Android are offered by different conglomerates and run on different kernels. A "custom blend" would probably be a nightmare to work with.

Simulates alternate speeds of light - This renders the clock useless. The speed of light is roughly 2.99x10^8 meters per second, far greater than 100 miles an hour. The adjustment for phone acceleration is also useless. While very high speeds can affect how time is perceived, normal daily use of a cellphone does not entail anything that would have a significant relativistic effect on the accuracy of clock time.

Wireless - as in cordless phone. This is the bare minimum a phone has to have in order to be a mobile phone, so advertising it as a feature feels dated by decades. Or, perhaps Munroe is implying the entire phone is without wires, in which case it wouldn't function.

Accelerometer screams in free fall– Another useless function. Rather than having some sort of feature to prevent breakage or cracking when a drop is detected, the phone just makes you more aware of its potential imminent doom.

When exposed to light, phone says "hi" - Bait and switch, and also a build from the previous joke. The implied feature is that the screen or camera will automatically adjust, but instead the phone is weirdly anthropomorphized.

==Transcript==
{{incomplete transcript}}

{{comic discussion}}

1353: Heartbleed

2014-04-09T06:30:53Z

108.162.250.231: /* Explanation */

{{comic
| number = 1353
| date = April 9, 2014
| title = Heartbleed
| image = heartbleed.png
| titletext = I looked at some of the data dumps from vulnerable sites, and it was ... bad. I saw emails, passwords, password hints. SSL keys and session cookies. Important servers brimming with visitor IPs. Attack ships on fire off the shoulder of Orion, c-beams glittering in the dark near the Tannhäuser Gate. I should probably patch OpenSSL.
}}

==Explanation==

In refrence to the "Heartbleed" vunerubilty in Open SSL see http://heartbleed.com/

The mouseover text cites the [http://en.wikipedia.org/wiki/Tears_in_rain_soliloquy Tears in rain soliloquy], the dying words of the replicant and main antagonist Roy Batty (played by Rutger Hauer) in [http://en.wikipedia.org/wiki/Blade_Runner Blade Runner].

{{incomplete|Created by a BOT - Please change this comment when editing this page.}}

==Transcript==
:Megan: Heartbleed must be the worst web security lapse ever.
:Cueball: Worst so far. Give us time.
:Megan: I mean, this bug isn't just broken encryption.
:Megan: It lets website visitors make a server dispense random memory contents.
:Megan: It's not just keys. It's traffic data. Emails. Passwords. Erotic faniction.
:Cueball: Is '''everything''' compromised?
:Megan: Well, the attack is limited to data stored in computer memory.
:Cueball: So paper is safe. And clay tablets.
:Megan: Our imaginations too.
:Cueball: See, we'll be fine.

{{comic discussion}}

Talk:8: Red spiders

2014-03-23T02:00:41Z

108.162.250.231: comment

In addition to [[8]] - [[Red spiders]], Red spiders also appear in comic [[42]] - [[Red Spiders 2]] and [[126]] - [[Red Spiders Cometh]] and are referenced in [[77]] - [[Counter-Red Spiders]] [[User:J-beda|J-beda]] ([[User talk:J-beda|talk]]) 01:51, 14 August 2012 (UTC)

The "cuboids" always reminded me of how I picture the "stars" in the Battle Room in ''Ender's Game'' -- mwburden [[Special:Contributions/70.91.188.49|70.91.188.49]] 22:45, 13 December 2012 (UTC)

The drawing is reminiscent of M.C.Escher style, isn't it ? [[Special:Contributions/37.160.7.233|37.160.7.233]] 19:58, 8 January 2013 (UTC)

But why *RED* spiders, or is there some reference that I am just too dense to fathom? [[Special:Contributions/68.115.52.179|68.115.52.179]] 06:33, 25 October 2013 (UTC)

I came to this page to say there is an actual insect known colloquially as red spiders. Dad was telling me about how his azalea plants got something powdery on them which he took to the nursery for identification. The nursery guy freaked out and said it was a highly contagious mite infestation ('get that stuff away from here!'). Even though they are a mite they are sometimes known as red spiders. So I guess these 6-legged "spiders" are a thing. - loudwhitenoise [[Special:Contributions/108.162.250.231|108.162.250.231]] 02:00, 23 March 2014 (UTC)

24: Godel, Escher, Kurt Halsey

2014-03-14T05:15:43Z

108.162.250.231: /* Explanation */

{{comic
| number = 24
| date = September 30, 2005
| title = Godel, Escher, Kurt Halsey
| image = godel_escher_kurthalsey.jpg
| titletext = I love the idea here, though of course it's not a great-quality drawing or scan.
}}

==Explanation==
{{Incomplete|Lack of information}}
The name of the comic is a take on the book {{w|Gödel, Escher, Bach}}. The book is about "strange loops", self-reference, and recurring patterns, partially shown through the works of the three people in its title.

{{w|Kurt Gödel}} was a 20th century mathematician most famous for mathematically proving that there are some mathematical truths that can't be proven (or some falsehood that can be proven to be true).

{{w|M. C. Escher}} was a 20th century artist most famous for mathematically-inspired engravings of tessellated animals, impossible scenes, distorted images that contained themselves, and so on.

{{w|Johann Sebastian Bach}} was a German composer and musician during the Baroque Period.

[http://www.kurthalsey.com Kurt Halsey] is a comic artist from Oregon.

It looks unclear whether the hatted guy is [[Black Hat]]. The character design wasn't yet standardized. The sarcastic comment suggests that it is.

==Trivia==
*This is the sixth comic originally posted on livejournal. The previous was [[1: Barrel - Part 1]]. The next was [[13: Canyon]]. View archive [http://liveweb.archive.org/web/20070927001941/http://xkcd-drawings.livejournal.com/?skip=40 here].
*[Original title]: "Strip series"
*[Original [[Randall]] quote]: "One of a series of strips I drew during a long and boring NASA lecture. It careens wildly from intellectual to chaotic to Godel, Escher, Bach to Kurt Halsey to chaotic and sappy." This might suggest that the image on LiveJournal was only part of this strip. Unfortunately, the image link on LiveJournal is broken.

==Transcript==
:Drawn during an unending NASA lecture.
:[Two people are talking, one in a hat.]
:Cueball: it's just so hard to compare kids now with kids in the past. you can't help but to belong to one group or the other.

:Cueball: and of course every generation seems awful to the one before it. look at quotes from throughout history.

:Hatted: yeah, and it sure would be nice to have some perspective on some of this stuff. I just don't know what to make of it.
:[Circles are appearing--maybe snow?]

:Cueball: i guess you do what you can to help the people around you and hope it turns out okay.

:Cueball: in the end, what else can you do?

:Hatted: lead a crusade?

:[We can no longer see the people, just the circles.]
:it's presentism, man. the idea that historical context is irrelevant, that we understand it

:all that we need take no warnings from the follies of the past. that we're facing something new.

:socrates couldn't imagine the internet. but people don't change.
:[We can start to see the corner of a darker circle in the lower right.]

:(The borders between the three panels on this line are cracking.)
:have you seen those collections of historical pornography? talk about historical context.

:did you know the first porn photo was bestial in.
:[inside a circle:] nature?

:at least that stuff was out of the mainstream
:[each word in one circle:]
:no
:just
:in
:history

:(the three panels have merged into one on each row.)

:i don't know about you, but
:[circled] I
:[uncircled] never

:even once seen

:[The circles are highly variable in size now, and pressed up against a larger one on the right side.]

:[There is mass of circles of different sizes, with some dark fissures in between, against the side of a large circle which we can see part of in the right half of the panel. They look like cells. There's a tiny square in the center of the giant cell.]

:[We see only the tiny square, centered. It has a few marks inside it.]

:[Closer, the square is divided into rectangles of different sizes, each of which has text in it.]

:[Much closer, we can see fragments of the text. Some are sideways, some are cut off, some are too small to read.]
:machine language translated by principles of isomorphism it is a consequence of the Church-Turing thesis that ...
:but how do you select the channel you wish to se-
:thou ... shou ... palin ... stri ... it is a ... crab ...

:[Closer still, we can just see a huge sideways s and h.]

:[Those letters are faded and mixed with a faded version of the next panel.]

:girls take boys away ...
:never be further than a phone call and a goosebumped shiver away ...
:drove all night listening to mix tapes ...
:the past is just practice
:[There is a heart at the bottom and, in the lower left, the name Kurt.]

:[The same as the previous panel, but with the words blurred out to scribbles.]

:[Jagged, shaded shapes and strands start to fall. Faint panel borders appear again. There is a person on the far right.]

:(Back to three panels per row.)
:[Cueball and Megan are standing amid the fragments.]

:Man: There's too much. And so little feels important.

:[The jagged edge of the shaded area is encroaching on the sides of the panel.]

:What do you do?

:[We see them from farther away through a rough hole in the shaded area. Bits continue to fall around them.]

:[She takes his hand.]

{{comic discussion}}
[[Category:Comics posted on livejournal]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Megan]]
[[Category:Romance]]
[[Category:Philosophy]]