explain xkcd - User contributions [en]

1518: Typical Morning Routine

2015-04-29T15:43:40Z

Eagle14: Small grammar/punctuation/clarity fixes

{{comic
| number = 1518
| date = April 29, 2015
| title = Typical Morning Routine
| image = typical_morning_routine.png
| titletext = Hang on, I've heard this problem. We need to pour water into the duct until the phone floats up and ... wait, phones sink in water. Mercury. We need a vat of mercury to pour down the vent. That will definitely make this situation better and not worse.
}}

==Explanation==
Waking up to an alarm can be annoying, especially when it is your partner's alarm, and they are slow to wake up and even then have difficulty figuring out how to turn the alarm off. This comic takes this situation to a ridiculous extreme, from whence the comic derives its humor, especially when paired with the title describing this situation as a "Typical Morning Routine". Of course the typical could refer only to the part of the "routine" until the phone is dropped into an air vent.

In this comic, a guy with morning hair is shown using his phone as his alarm clock. (This is clearly not [[Cueball]] as he, per definition, has no hair. Although this guy has less hair than [[Hairy]] usually does, it is black in the fourth frame, and hairy is just a description of any hairy guy in xkcd.) We never see who he is sharing the bed with, a person that must get more and more angry with him and his alarm. (We have no reason to assume it is [[Megan]] , and we do not even know if it is a girl.)

It can sometimes be complicated to turn off the alarm on a {{w|smartphone}} when groggy. The guy has apparently exited the alarm app by mistake. In some OSes, simply exiting the app doesn't close it, requiring you to use the app switcher to close it. (As of when this comic was posted, [[Randall]] uses both iOS and Android according to [[1508: Operating Systems]] - although there is no reason to be certain that the character in this comic is using the same operating systems as Randall).

After giving up on shutting the alarm app off, Hairy, in annoyance, gets the brilliant idea of trying to remove the battery (in the dark) to shut off his phone forcefully, instead of just trying to turn it off. (This narrows it down to Android phones, since iPhones do not have consumer removable batteries.) However, in this process, he accidentally drops his device down an {{w|air vent}} next to the bed. Such a vent for an {{w|underfloor air distribution}} may not be very deep until it reaches a bend, so the phone can be expected to survive the fall. Usually such a {{w|Register (air and heating)|vent}} will have some sort of grille preventing anything large from falling into it. It's tricky to notice, but there does seem to be a grille, but it could either be missing a few parts due to poor maintenance, or this phone must have been small enough (and fallen in the right way) to slip through it anyway.

If they were a little handy, they would probably be able to open the vent and retrieve the phone. But of course it could either have settled too deep for them to retrieve (sliding further in to the system after the first short fall), or they do not have the tools to do so(maybe they live in a rented apartment). So being unable to get it out, Hairy attempts to remotely {{w|Brick (electronics)|brick}} the phone from his laptop. (That is, erase important system files, which renders the device as useful as a brick).

However, Hairy seems to have accidentally put the device into {{w|airplane mode}} in the confusion, thereby cutting off all {{w|wireless communications}} with the device. Airplane Mode also has a side effect whereby turning off all communication components, the phone uses less energy, so the phone may now last a week, or at least rather longer than the typical day or so. As can be seen in the first two panels, the alarm did not turn on the screen, as it should then have been visible in the comic. This also saves energy. But a smartphone playing loud sounds in airplane mode typically only lasts a day or so before the battery charge runs out.

Rather than finding a solution to the problem with the phone, Hairy proposes that they just move out instead. His unseen partner in the bed replies to this in the title text.

Relevant for the title text: There is a semi-common logic puzzle involving a ping-pong ball falling down a pipe with a kink in it. In this puzzle, the solution is to pour water into the pipe until the ping-pong ball floats up.

In the title text, Hairy's partner, pressed by the threat of having to move out, remembers this problem and attempts to apply it to this situation. Then realizing that phones do not float in water, suggests using {{w|Mercury (element)|mercury}} instead of water. The phone would certainly float on mercury, as it is a very dense liquid (the only metal that is liquid at room temperature). It is though not certain if this would be the case if the phone is lying flat on the surface. In this case the mercury may just push it down towards this surface without getting under it.

The extremely toxic nature of mercury makes pouring it into the air supply a very dangerous idea. Also the required amount of mercury would be extremely expensive. The last line in the title text is Hairy's reply to his partner, dripping with heavy sarcasm, stating that the mercury idea would ''definitely make this situation better and not worse''.

If they were actually ready to pour mercury down the went, or brick the phone (ruining it anyway) then maybe they could just pour enough water into the vent instead, until the phone would shut down by being flooded, therefore short-circuited. This would not work if the phone was waterproof. Some rugged phones and phone cases do actually float on water, and thus using water would work.

Of course, all these great ideas they have would probably not have come up if they had not just been awakened brutally by a very loud alarm that Hairy fails to silence. It is very difficult to think clearly in such a stressful circumstance.

This comic follows a similar storyline to [[349: Success]], as Cueball, like Hairy here, encounters an issue and attempts proceedingly more absurd solutions to the issue.

==Transcript==
:[The panel is completely black, with white text. Small lines indicate from where the two voices are coming, and also from where the alarm goes off. A small broken square surrounds the first word spoken.]
:Alarm: '''Bleep Bleep'''
:Voice (right): Urgh
:Voice (left): Your alarm is going off
:Voice (right): Huh?
:Voice (left): Make it stop.
:Voice (right) Urrgh

:[The panel is completely black, with white text. Small lines indicate from where the two voices are coming. Several small lines surrounds the last "sound" which is not spoken. The alarm noise is continued from the previous panel and continues over the top of the frame directly into the next panel.]
:Alarm: '''Bleep Bleep Bleep B'''
:Voice (left): Hit snooze.
:Voice (right): I'm ''trying''. I closed the alarm app and I can't... I'll just pop out the battery.
:Voice (right): Whoops!
:Clang

:[The lights have turned on so it is now a white panel with black text. The voice to the right came from Hairy with morning hair. He is leaning over the side of the bed, looking down the air vent through which he has dropped the phone. The other person to the left is not shown. The alarm noise (now coming from the air vent as visualized by the lines coming out of the vent) still continues from the previous panel and continues over the top of the frame directly into the next panel.]
:Alarm: '''eep Bleep Bleep Ble'''
:Off-Screen voice: Make it stop!
:Hairy: It... fell down the vent.

:[Hairy is sitting in his bed with a laptop. The person to the left is still off-screen. The alarm noise still continues from the previous panel and continues over the top of the frame out of the comic the the right.]
:Alarm: '''ep Bleep Bleep Bleep Ble'''
:Off-Screen voice: Can you brick it remotely?
:Hairy: Trying... I think I fumbled it into airplane mode?
:Off-Screen voice: The battery could last for weeks.
:Hairy: You know, maybe we should just move.

{{comic discussion}}

[[Category:Sarcasm]]
[[Category:Comics featuring Hairy]]

1515: Basketball Earth

2015-04-27T22:19:37Z

Eagle14: Minor grammar/punctuation fixes

{{comic
| number = 1515
| date = April 22, 2015
| title = Basketball Earth
| image = basketball earth.png
| titletext = How many points do you get for dunking every basketball in existence at once?
}}

==Explanation==
In this comic, [[Cueball]] is repeatedly attempting to make a comparison for the {{w|Earth}}-{{w|Moon}} system. We can guess that he means to say that if the Earth were the size of a {{w|Basketball (ball)|basketball}} (about 25 cm in diameter), the Moon, at the same scale, would be less than 7 cm in diameter, a typical size for other smaller balls in different sports.

Cueball handily illustrates this with two "balls" of the relevant sizes. At first you think that they just look like the Earth and the Moon. But they are invisibly suspended, and — as seems clear from the first row of panels — they are actually the real Moon and Earth shrunk to the relevant size, hence the title ''Basketball Earth''.

This would place Cueball and his "friends" in {{w|God}}-like positions, outside Earth. Maybe they are even in a different dimension, since they can stand and observe the system.

But, repeatedly, before Cueball can finish with this common type of comparison, he is interrupted and must begin all over again. We thus never learn what object he would have compared the Moon with. It seems, likely, however that he would use another ball for the comparison. And the best ball to use would be a {{w|tennis ball}}. See the same sort of comparison of Earth/Moon with basketball/tennis ball in this illustrative video that asks the question: [http://blogs.discovermagazine.com/badastronomy/2011/02/24/how-far-away-is-the-moon/ How far away is the Moon?]. From this it is also obvious that the system Cueball shows is not to scale with regard to that distance, which should be 7.37 m! This is not necessarily a mistake of the comic, since Cueball never claims that these two balls are in orbit or that they are even the real ones. He is just (in vain) trying to make a size comparison of the two, though perhaps further exposition and demonstration might take place after the size comparison. It is also possible that the moon is actually back in the background at the appropriate distance, further from the viewpoint of the comic than it seems.

A basketball has an average diameter of 24.6 cm (9.7 inches) vs. a tennis ball, which has an average diameter of 6.7 cm (2.6 inches). The ratio between the size of a tennis ball and the size of a basketball is 0.273, which is the same (to three digits) as the ratio given on the Wikipedia page for the Moon: ''Mean radius 1737.10 km (0.273 Earths)''. If he had used a {{w|Baseball (ball)|baseball}}, which is slightly larger, this would still be good enough for demonstrative purposes, as it would have been with an apple.

It is common to describe the relationship between very large (and very small) objects by analogy to common objects on a more human scale. Here is a similar example where someone has made a comparison of the sizes of the Solar system based on a [http://www.backwoodshome.com/articles/silveira60.html Sun the size of a basketball]. And here, coming from smaller scales, is an [http://www.infoplease.com/dk/science/encyclopedia/atoms.html#ESCI024ATOMS001 example] that states the following: "Imagine an atom magnified to the size of a football stadium. The nucleus of the atom would be the size of a pea in the centre of the stadium."

It is almost certainly not a coincidence that this comic was released on {{w|Earth Day}}, which is celebrated annually on April 22 to demonstrate support for environmental protection. This seems to be something that [[Randall]] cares about a lot, as he has made several comics demonstrating the need for the human race to begin taking better care of our globe. See, for instance, [[1321: Cold]] and [[1379: 4.5 Degrees]].

This comic clearly demonstrates four examples where the inhabitants of Earth did not take care of the well being of our globe, although here on a somewhat grander scale than what individuals can usually do. The typical case is that people did not do this out of bad intentions, but only because they were careless, curious, playful, or just plain stupid.

This comic may be seen as a spiritual successor to [[445: I Am Not Good with Boomerangs]] and its follow-up, [[475: Further Boomerang Difficulties]] in depicting various failed outcomes to the same opening panel.

===Interruptions===
The four interruptions are described and explained below. Each of the four attempts has its own row of four panels in the comic. It is clear from panels one and two in each row that the Basketball Earth is rotating quite fast compared to the time frame of the comic since the {{w|continents}} have moved considerably between frames. It is thus not necessarily the interrupters that have moved the Basketball Earth between frames two and three, except of course in the final interruption.

No matter how fast it rotates or whatever happens, we always see the Basketball Earth from the same side, as seen from far above the {{w|Atlantic Ocean}}. We can see the continents of the {{w|Americas}} as well as {{w|Africa}} and sometimes part of {{w|Europe}}, all of which are the borders for this ocean.

It seems most likely that Cueball starts all over every time, with a completely fresh and new Earth-Moon system, since they look the same regardless of the catastrophe befalling the prior Basketball Earth, and the interruptions—the second especially—would be difficult to reverse. We can thus suppose that there is still "normal" life going on for each Basketball Earth before the interruption. Most or all of this life would presumably perish for all of the last three cases.

====Black Hat====
In the first interruption, [[Black Hat]] comes in and is amazed by this cool floating globe. Of course, being Black Hat, he has to prod this nice globe with a digit. But by putting his finger into one of the oceans of this "real" Basketball Earth without a second thought, he apparently generates a {{w|megatsunami}} that rolls in over an unidentified city with skyscrapers, utterly dwarfed by a breaking wave.

This is similar to a scene in "{{w|Men in Black II}}" where K messed with a globe that actually is a small planet, and his finger become visible in the sky of its inhabitants. It is also reminiscent of {{w|Deep Impact (film)|Deep Impact}} in which a meteor strike causes exactly such a tsunami to hit the {{w|East Coast of the United States}}. Since Black Hat puts his finger down in the Atlantic Ocean, the tsunami would hit all bordering coastlines. Since the coast seems to be an eastern coast (assuming a vantage point of South --> North), and because Randall lives there, the city could be {{w|New York City}} or {{w|Boston}} or one of the other large US cities on the East Coast. Of course, the wave would also affect the coast line (far into land) for all the other continents.

====Megan====
The second interruption occurs when [[Megan]] arrives and pours liquid (perhaps water) from a sports {{w|water bottle}} onto the Basketball Earth, seemingly flooding its entire surface. This would cause {{w|List of flood myths|extensive flooding}}, almost certainly extinguishing all multicellular land-dwelling life. The most familiar analogous situation is from the {{w|Bible}} in the {{w|Genesis flood narrative}} about {{w|Noah's Ark}}. The deluge from Megan's bottle would also change the composition of the ocean and create enormous churn and pressure changes, with widespread or catastrophic effects even on multicellular marine life.

====Cat====
In the third interruption a cat walks into shot and then playfully attacks the Basketball Earth rolling around with it like it would do with a ball of {{w|yarn}} (see real life example in [https://www.youtube.com/watch?v=k1rTAI2aExI this video]).

The people living upon this Basketball Earth would experience cataclysmic events far greater than Blackhat's digital prodding caused, especially as the Basketball Earth is no longer suspended and was thus taken "out of its orbit" and will eventually hit the floor very hard. One way or another, that will surely cause (undepicted) disasters of tremendous magnitude.

====Ponytail====
In the fourth and final interruption, [[Ponytail]] uses Basketball Earth as an actual basketball. She comes running by Cueball, grabs the Basketball Earth, probably bouncing it off the floor while {{w|Dribbling#Basketball|dribbling}} towards the {{w|Backboard (basketball)|basketball hoop}} where she actually jumps in an attempt to {{w|Slam dunk|dunk}} the Basketball Earth. This would ''not'' be good for any residents of Basketball Earth; the combined pressure, movement, and impact damage from this simple sequence would surely kill off all complex life on Basketball Earth.

===Title text===
This simile-callback is continued in the title text with the idea that "every basketball in existence" (i.e., every basketball upon the Basketball Earth, as well as the Basketball Earth itself) is counted towards the score from a single dunking. Randall may have a good estimate of how many basketballs there are, perhaps through research for some [[what if?]] question or other research, but almost certainly assumes that there are no extraterrestrial basketballs ''not'' on Basketball Earth. But there might be some question about whether the Basketball Earth's own sub-scale basketballs fall within the regulations. If recursion exists, there would be an infinite amount of balls shot, but not scored, since it is illegal to have more than one basketball in play at a time according to basketball rules.

==Transcript==
:[Cueball is standing next to a floating Basketball Earth indicating it with his left hand. The continents are clearly visible as seen from above the Atlantic Ocean. This remains the same all through the comic, except that the Basketball Earth rotates a bit from frame to frame.]
:Cueball: If the Earth were the size of a basketball,

:[Cueball is now indicating, with his right hand, a small pockmarked moon (also floating), in the correct proportions (regarding size not for their distance) to the Basketball Earth, which is on his other side. Black Hat walks into the panel towards Earth.]
:Cueball: The Moon would be—
:Black Hat: Hey, cool!

:[Black Hat is touching the Basketball Earth with a digit.]
:Cueball: Um.

:[In the next scene we see a megatsunami on the verge of crashing down onto a coastal city with skyscrapers. The A's are cut of on each side of the panels frames, i.e. they begin outside and finishes outside the frame.]
:Aaaaaaaa

:[Back to Cueball standing with the Basketball Earth in the same position as the first panel.]
:Cueball: Let's try that again. If the Earth were the size of a basketball,

:[Same situation as when Black Hat walked in, except now it is Megan that walks into the frame towards the Basketball Earth holding a sports water bottle.]
:Cueball: The Moon would be—

:[Megan squirts the Basketball Earth with the liquid in her water bottle while Cueball just stands watching with the Moon behind him].

:[Megan just walks away while Cueball stares at his "water" Basketball Earth where the continents have disappeared completely beneath the liquid.]

:[Back to Cueball standing with the Basketball Earth in the same position as the first panel.]
:Cueball: If the Earth were the size of a basketball,

:[Same situation as when Black Hat walked in, except now he spots a cat coming into the frame from the left.]
:Cueball: The Moon— would…

:[While Cueball watches with the Moon behind him, the cat jumps at the Basketball Earth.]
:Cat: Mrowl!

:[Cueball continues to watch while the cat rolls around playing with the Basketball Earth as if it was a ball of yarn.]
:Cat: Rrrrr

:[Back to Cueball standing with the Basketball Earth in the same position as the first panel.]
:Cueball: If the Earth were the size of a basketball,

:[Same situation as when Black Hat walked in, except this time it is Ponytail who enters the frame at a run coming from the left.]
:Cueball: The Moon would, uh…

:[While Cueball watches with the Moon behind him, Ponytail has grabbed the Basketball Earth and is dribbling it out of the frame, still running.]

:[Zoom out from Cueball who continues to watch while Ponytail reaches a basketball hoop and jump towards it with the Basketball Earth, obviously in an attempt to make a slam dunk.]

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Animals]]

1517: Spectroscopy

2015-04-27T21:58:00Z

Eagle14: Some grammar/spelling fixes.

{{comic
| number = 1517
| date = April 27, 2015
| title = Spectroscopy
| image = spectroscopy.png
| titletext = Although right now I'm more excited about ESPRESSO's radial velocity measurements, so I'm listening to This Kiss, her song about measuring "centrifugal motion" on "a rooftop under the sky".
}}

==Explanation==
This comic mixes the method of using ''{{w|spectroscopy}}'' to detect {{w|oxygen}} on {{w|exoplanets}} (planets outside our {{w|Solar system}}) with [http://www.azlyrics.com/lyrics/faithhill/breathe.html the lyrics] for the {{w|Faith Hill}} song "{{w|Breathe (Faith Hill song)|Breathe}}" (listen to [https://www.youtube.com/watch?v=yCmsZUN4r_s "Breathe" on YouTube]).

From the lyrics:
:''I watch the sunlight''
:''dance across your face''
:''I can '''feel''' you breathe''
In the comic the word '''feel''' has been changed to '''see'''. The two first panels are one line in the song. The last line is from the chorus and is repeated five times during the song, although not right after the first two lines.

In the first and second panel the singer examines the spectra of a remote planet by ''watching the sunlight'' during the transit of the planet as this sunlight ''dances across the planet's face''. Finally we determine that breathable oxygen exists. Since we cannot (as Faith can) ''feel'' the planet we have to ''see'' it. And by doing this ''I can see you breathe''.

Measuring the light output of stars (spectra) we are able to determine a number of details of the star, including rotation, relative radial velocity, chemical composition, temperature, and to some degree, distance and size. When a planet, as pictured, moves between the star and the observer, then by looking at the spectrum received, the viewer is able to determine the contents of the planet's atmosphere from the specific wavelengths of light that are {{w|Absorption spectroscopy|absorbed}} in this. If it turns out that the atmosphere absorbs the lines corresponding to molecular oxygen (O<sub>2</sub>) this is a clear indication that the planet has large quantities of breathable oxygen (but {{w|Exoplanet#Abiotic_oxygen|not necessarily life}}). Since for most (though {{w|Anaerobic_organism|not all}})
forms of life as we know it to exist and breathe, there must be oxygen in large amounts in the atmosphere, it is clear why [[Randall]] would be interested in exoplanets with oxygen.

This comic came out four days after this article about [http://www.huffingtonpost.com/2015/04/23/nasa-nexss-search-for-life_n_7123788.html NASA's New NExSS Initiative]. {{w|NASA}} will search for signs of life on other planets, for instance by using "the light passing through the atmospheres of these exoplanets". And they "will study chemicals that have been detected on other worlds, such as oxygen and methane, to see if they were produced by biology".

The title text refers to determining {{w|radial velocity}} in the {{w|ESPRESSO}} program (Echelle SPectrograph for Rocky Exoplanet- and Stable Spectroscopic Observations). By noting that the radial velocity of the star changes slightly as the planet that orbits it moves around the star (centrifugal acceleration), the ESPRESSO program should be able to detect the masses of planets as they are moving towards the Earth in their orbit around their distant stars. The ESPRESSO program is so precise that it should be able to detect {{w|Terrestrial planet|planets as small as Earth}} and the other of the Solar systems inner planets.

Randall is now even more excited about ESPRESSO than he is about the oxygen levels, because it is now possible to detect these "very" small planets. So he is no longer listening to "Breathe", but to another Faith Hill song: "{{w|This Kiss (Faith Hill song)|This Kiss}}" (listen to [https://www.youtube.com/watch?v=dls_cBmUt7Q "This Kiss" on YouTube]).

From the [http://www.azlyrics.com/lyrics/faithhill/thiskiss.html lyrics]:
:''It's centrifugal motion''
:''On '''the''' rooftop under the sky''
The first line is part of the chorus and it is repeated four times. But not in connection with the second line, which is changed a bit, so '''the''' is changed to an '''a'''. Also the "on" is not part of the quoted line in the title text.

The song is not about measuring but, of course, about the (a) kiss. Since the ESPRESSO is part of the {{w|Very Large Telescope}}, it is located on the {{w|Cerro Paranal}} mountain in the {{w|Atacama desert}} in {{w|Chile}} at an elevation of 2,635 meters (8,645 ft.) above sea level. So it could be said that it is measuring on a rooftop under the sky. Although it is radial velocity it measures not {{w|Centrifugal force|centrifugal motion}}, the object it does measure will all be experiencing this {{w|fictitious force}} (also see [[123: Centrifugal Force]]), as the planets are in orbit around a star.

Randall has previously made [[:Category:Exoplanets |several references to exoplanets]] in his comics, most notable are the two comics with the same name: [[786: Exoplanets]] and [[1071: Exoplanets]]. The latter comic came out when there were exactly 786 exoplanets found. Today more than 1900 has been discovered (1915 as of Wikipedia on the release day of this comic), much more than twice that amount. And now they can find even smaller planets, and detect the atmosphere since the first exoplanet comic came out in 2010.

==Transcript==
:[A dark panel with a bright star in the center. To the left a planet (drawn as a new moon) approaches the star. Text is written above in white with two musical notes, one on each side of the text.]
:I watch the sunlight

:[Same image but now the planet {{w|Transit (astronomy)|transits}} the star. Small lines around the planet indicate the atmosphere, as seen from the light from the star passing through it. Text is again written above in white with two different musical notes, one on each side of the text.]
:Dance across your face

:[A white frame with a black line. It Is the spectrum of the planets atmosphere. Two distinct absorbtion peaks are visible. The first one is labeled with an arrow. Text is again written above, now in black, with two, again, different musical notes, one on each side of the text.]
:I can see you breathe
:Label: O<sub>2</sub>

:[Below the panels is the following caption:]
:'''Faith Hill on exoplanet spectroscopy'''

{{comic discussion}}

[[Category:Science]]
[[Category:Astronomy]]
[[Category:Exoplanets]]