explain xkcd - User contributions [en]

Talk:1486: Vacuum

2023-03-06T17:12:53Z

Wilberforce:

This is obviously a reference to [http://en.wikipedia.org/wiki/Vacuum_energy Vacuum Energy].
The "Tremendous" part is because calculation based on quantum electrodynamics suggest it should be 100 order of magnitudes larger than measured (That is a "1" with 100 zeros after it). [[Special:Contributions/141.101.98.202|141.101.98.202]] 09:42, 13 February 2015 (UTC)
:AKA a googolplex -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 12:55, 13 February 2015 (UTC)
::No, that's just a googol. [[Special:Contributions/141.101.104.77|141.101.104.77]] 13:55, 13 February 2015 (UTC)

Wondering if this is a reference to Terramex [http://tvtropes.org/pmwiki/pmwiki.php/VideoGame/Terramex] {{unsigned|Stese}}

:My antivirus says this link is [[609|not safe]]. [[Special:Contributions/141.101.104.77|141.101.104.77]] 10:50, 13 February 2015 (UTC)
::I see what you did there. - Equinox [[Special:Contributions/199.27.128.120|199.27.128.120]] 17:03, 13 February 2015 (UTC)
:::can't speak to your antivirus, but I don't see any problem with the site (TVTropes) - it's a page about a video game called "Terramex" (which in summary is a game about adventurers finding a scientist that can prevent a meteor from hitting Earth) - no idea what that might have to do with vacuum energy, vacuum cleaners, living rooms, berets, or billiard balls, or even flying, but oh well -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 12:55, 13 February 2015 (UTC)
::::One of the methods of getting around in Terarmex is flight on a vacuum cleaner, as depicted in the last panel. ([[User:Stese|Stese]])

:::::You completely missed the point. xkcd comic 609 referenced TVTropes' addictive power. You can get trapped in the web of links all day. Therefore, 141.101.104.77 was simply joking that their antivirus had detected this, and warned them that the site was not safe. I understand not seeing the comic before, but the IP did provide a link to explain the joke. [[User:NealCruco|NealCruco]] ([[User talk:NealCruco|talk]]) 18:00, 13 February 2015 (UTC)

I tried to read this explanation, but couldn't because of xkcd 1240 [[Special:Contributions/141.101.98.63|141.101.98.63]] 10:23, 13 February 2015 (UTC)
I was expecting something related to February 14. You know, something about YouTube, IBM, ENIAC, Pale Blue Dot, Shoemaker, Hilbert, Catalan, etc. [[Special:Contributions/141.101.104.77|141.101.104.77]] 10:39, 13 February 2015 (UTC)

Isn't 'the universe is mine to command!' a quote from Aladdin?? {{unsigned|Atty70}}

:Yes it is a quote from Aladdin (by Jafar when he becomes a genie) [http://www.imdb.com/title/tt0103639/quotes]. It is also a quote from "insert your bond/sci-movie here" as it is the usual goal for any scientist that creates a lot of energy or a new weapon (only exception to this is in the real world with Einstein and the atomic bomb). Maybe something to add to the description (looking at someone with better english and story telling skills than I got) [[User:Aquaplanet|Aquaplanet]] ([[User talk:Aquaplanet|talk]]) 12:44, 13 February 2015 (UTC)

::One [http://en.wikipedia.org/wiki/J._Robert_Oppenheimer#Trinity actual quote] related to atomic bomb is not so different: "I am become Death, the destroyer of worlds." -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 17:20, 14 February 2015 (UTC)

faced?[[Special:Contributions/108.162.249.157|108.162.249.157]] 12:53, 13 February 2015 (UTC)

Has anyone found a calculation or example of how much energy would be required to run a "vacuum (in the space time sense) cleaner"? And what would it be cleaning exactly? [[User:Iggynelix|Iggynelix]] ([[User talk:Iggynelix|talk]]) 18:50, 13 February 2015 (UTC)

:I suppose it would clean a soft vacuum into a hard vacuum, so it would be cleaning particles. Which is kind of exactly what vacuum (in the household appliance sense) cleaner does, just on a larger scale. [[User:Shishire|Shishire]] ([[User talk:Shishire|talk]]) 20:57, 13 February 2015 (UTC)

Can we get that last panel as a tee shirt? {{unsigned|dragonkingofthestars}}
:I want one too. But i must say i found the idea of accidentially tapping vacuum energy with a vacuumer extremely far fetched. I mean it was obvious what beret gey was ''trying'' to do, but to let him succeed ?!? ;-) --[[User:Wilberforce|Wilberforce]] ([[User talk:Wilberforce|talk]]) 22:37, 13 February 2015 (UTC)
:Two words: [[1293|Soup Socket]]... [[Special:Contributions/141.101.98.192|141.101.98.192]] 01:26, 14 February 2015 (UTC)

Is supernatural powers for Beret Guy an official XKCD theme now? [[User:Djbrasier|Djbrasier]] ([[User talk:Djbrasier|talk]]) 04:26, 14 February 2015 (UTC)

"On an additional note, many scientific breakthroughs in history have been made because the person making them did not realize they were supposedly impossible ..." On an additional, additional note, the vacuum cleaner was invented based on a music hall demonstration of a cleaning machine that blew instead of sucked, and the person watching the demonstration got the idea that the machine would "suck" less if it sucked, if you get my meaning. https://en.wikipedia.org/wiki/Vacuum_cleaner#Vacuum_cleaner --[[User:RenniePet|RenniePet]] ([[User talk:RenniePet|talk]]) 12:14, 14 February 2015 (UTC)

The energy for black hole evaporation doesn't come from the vacuum state, it comes from the mass of the black hole itself. The explanation given on this page is incorrect. {{unsigned ip|173.245.53.125}}

In the game Final Fantasy V, the villain ExDeath (or depending on the translation X-Death, Exdeath, Ex Death, EXDeath and so) 's objetive is control the energy and power of the Void/Vacuum (depending on translation) to command the universe, spiler: He was unable to control the tremendous power and become Neo Exdeath (again spelling issue) who want use the void to make everything into nothing, also both as boss have a move called "Vacuum Wave" and in Dissidia they signature move is "Power of the Void" and in Dissidia 012 is "The laws of the universe mean nothing!", ultimately was defeathed by the hero(e)s. Funny that Barret guy want use the Vacuum/Void to acomplish what ExDeath fail to do with the Void/Vacuum. --[[Special:Contributions/141.101.103.216|141.101.103.216]] 06:22, 16 February 2015 (UTC)

Is this the same thing as 1404? I don't understand physics well enough to know if it does or doesn't. [[User:Djbrasier|Djbrasier]] ([[User talk:Djbrasier|talk]]) 15:44, 16 March 2015 (UTC)

now... TO UNLOCK THE TREMENDOUS POWER OF CLEANING BWAHHAHAHAHAHAHAHA[[Special:Contributions/173.245.54.5|173.245.54.5]] 13:55, 23 December 2015 (UTC)X=X+1

I challenge the statement that "spin-stabilised magnetic levitation" was a breakthrough invention, and would like to hear a few more of those "many" other examples. ;) --[[User:Wilberforce|Wilberforce]] ([[User talk:Wilberforce|talk]]) 17:12, 6 March 2023 (UTC)

532: Piano

2023-03-06T16:28:57Z

Wilberforce: /* Explanation */ another one

{{comic
| number = 532
| date = January 19, 2009
| title = Piano
| image = piano.png
| titletext = Good thing he didn't make it smaller, or it'd need someone three inches tall to play it.
}}

==Explanation==
This comic is the reverse of the [http://www.netfunny.com/rhf/jokes/old90/304.html "twelve inch pianist" joke] that appeared in the rec.humor.funny {{w|Usenet}} {{w|Usenet newsgroup|newsgroup}}.

In the original joke, a man found a genie in a bottle, and it is implied that he wished for a "twelve inch ''penis''," but the genie misheard him and instead granted him a "twelve inch ''pianist''." The crux is that the word ''pianist'' sounds similar to the word ''penis''; the joke also relies on the common trope of {{w|genies}} granting {{w|wishes}} (as in the tale of '''''{{w|Aladdin|Aladdin and the Wonderful Lamp}}'''''), sometimes with creative (mis)understanding or literalism as {{tvtropes|AnAesop|an Aesop}} to be wary about what you wish for, as well as the common stereotype that larger penises are more desirable.

In this comic, the opposite happens: Cueball wished for a "twelve inch ''pianist''" to play his miniature piano, but was misheard by the genie, implying that the genie instead granted him a "twelve inch ''penis''." Megan has understood this implication, and therefore wants to have sex with Cueball (in accordance with the aforementioned stereotype).

The title text suggests that if Cueball had made a smaller piano – and had thus wished for a smaller ''pianist'' – he would have instead received a ''smaller penis'', making him ''less'' desirable according to the stereotype.

Genies (or the magic lamps containing them) are mentioned in at least five other comics:
*[[152: Hamster Ball]]
*[[879: Lamp]]
*[[1391: Darkness]]
*[[2193: Well-Ordering Principle]]
*[[2741: Wish Interpretation]]

==Transcript==
:[Cueball is holding a box with an open lid. A miniature piano is inside. Megan is looking at it]
:Cueball: My hobby is making miniatures. Check this out — it's a fully-functional grand piano.
:Megan: Whoa — beautiful.

:[Cueball looks at the miniature piano.]
:Cueball: Sadly, I've never heard what proper music sounds like on it—the keys are too small to play.

:[Cueball closes lid to the piano.]
:Cueball: I once asked a genie for someone who could play it for me, but I think he misheard.
:Megan: ...are you doing anything later?

==Trivia==
For the record, pianist /'piənɪst/ and penis /'pinɪs/ are near homophones in English. This is because pianist has a different stress pattern than piano /pi'æno/. The vagaries of the English language.

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

Talk:1486: Vacuum

2015-02-13T22:37:54Z

Wilberforce:

Talk:1276: Angular Size

2013-10-13T13:24:54Z

Wilberforce:

What is the meaning of "football field" in panel #2? --[[User:Kevang|Kevang]] ([[User talk:Kevang|talk]]) 04:50, 11 October 2013 (UTC)
:I was wondering the same thing. Probably misplaced text. [[User:Irino.|Irino.]] ([[User talk:Irino.|talk]]) 05:49, 11 October 2013 (UTC)
::It does seem to be misplaced, but if that's the only glitch, this is the only panel without a unique reference object. "20 football pitches long" isn't all that easy to grasp. [[User:Jameslucas|jameslucas]] ([[User talk:Jameslucas|" "]] / [[Special:Contributions/Jameslucas|+]]) 09:09, 11 October 2013 (UTC)
:::The image is fixed by Randall. I did an update here.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 11:28, 11 October 2013 (UTC)
::::Well, that's a letdown. I'm surprised Randall didn't use Heathrow. [[User:Jameslucas|jameslucas]] ([[User talk:Jameslucas|" "]] / [[Special:Contributions/Jameslucas|+]]) 13:42, 11 October 2013 (UTC)

I haven't done any lookups or maths to check these, but give the size of these as "stars" in the sky, everything from panel 2 onwards seems to me to be an order of magnitude or two too large. [[User:Markhurd|Mark Hurd]] ([[User talk:Markhurd|talk]]) 05:17, 11 October 2013 (UTC)
: Not really. You see the stars and planets as points because their angular size is lower than your eyes' resolution. They have measurable (or, in case of really distant or small objects, computable) angular sizes. For stars etc. these angular sizes are really small - but Earth is quite big, so if you cut a portion of a sphere the radius of Earth corresponding to these small solid angles, you get sizable areas. I haven't checked Randall's math, but I'd rather believe his results. If it is non-intuitive for you consider the Sun and Moon example - when observed by naked eye, the Moon looks for you as being the size of a dime held up in your hand - and yet it's shadow during an eclipse covers quite an area of Earth's surface. It is true that sizes of some of these "footprints" are quite surprising compared to other ones. [[Special:Contributions/89.174.214.74|89.174.214.74]] 08:55, 11 October 2013 (UTC)
:: Definitely surprising. I'll put faith in Randall doing his math correctly, but still needed to check on a couple of these because they did elicit a "What? No. Really? Can't be." reaction. Using the formula described in the Explanation above, for Venus I get 12742 km (Earth radius) * 12104 km (Venus diameter) / 38000000 (shortest distance to Venus) = 2.03 km.
:: Hard to picture that something that is such a small dot in the sky is actually directly over such a large patch of ground. But there you are.
[[Special:Contributions/67.51.59.66|67.51.59.66]] 17:11, 11 October 2013 (UTC)
::: The question that sprung to my mind was, ''which'' distance is he using for the planets and asteroids, since those vary hugely depending on where objects are relative to each other along their orbits. Is he going with closest approach, maybe? Or the distance that we happen to be at just this instant? --[[User:Rmharman|Rmharman]] ([[User talk:Rmharman|talk]]) 21:42, 11 October 2013 (UTC)
::::I just checked for Deimos, and got to ~50 mio km, so that´d be the closest approach. --[[User:Wilberforce|Wilberforce]] ([[User talk:Wilberforce|talk]]) 13:24, 13 October 2013 (UTC)

Does someone know how to use LaTeX formulas? And if so, can they translate my formula into something more pleasing to the eye? [[User:Irino.|Irino.]] ([[User talk:Irino.|talk]]) 05:49, 11 October 2013 (UTC)

According to the wikipedia page, the M25 is 117 miles long. That sounds more like "37 miles across" to me. [[User:Kaa-ching|Kaa-ching]] ([[User talk:Kaa-ching|talk]]) 08:46, 11 October 2013 (UTC)
: it originally stated 15 miles, someone has fixed it now. Thanks! [[User:Kaa-ching|Kaa-ching]] ([[User talk:Kaa-ching|talk]]) 11:35, 11 October 2013 (UTC)

Neither the sun or moon, nor Messier 25 (declination -19°) can ever culminate in the zenith over London. :-( Admittedly, Townsville, Australia would be sort of overwhelmed by M25. --[[Special:Contributions/129.13.72.198|129.13.72.198]] 11:27, 11 October 2013 (UTC)
: M25 is a reference to the highway that surrounds London, not the Messier object, which is probably nowhere near the angular size of the moon. [[Special:Contributions/65.129.214.100|65.129.214.100]] 15:17, 11 October 2013 (UTC)
::Why would Randall choose London, if it wasn´t for the obvious disambiguity of the name M25? ----[[User:Wilberforce|Wilberforce]] ([[User talk:Wilberforce|talk]]) 12:33, 13 October 2013 (UTC)

Does anyone know why the exoplanet "HD 189733 b" is labled as "Permadeath" ? Same question for the other weird names in the same pannel (the "tilde on keyboard" one) ? [[User:Jahvascriptmaniac|Jahvascriptmaniac]] ([[User talk:Jahvascriptmaniac|talk]]) 11:32, 11 October 2013 (UTC)
: A reference to [[1253|Exoplanet Names]]. [[User:Squornshellous Beta|Squornshellous Beta]] ([[User talk:Squornshellous Beta|talk]]) 12:08, 11 October 2013 (UTC)

If you were looking from the center of the earth, as the situation suggests, wouldn't the M25 be reversed, east-to-west, as you look at the sun and the moon?--[[Special:Contributions/76.105.133.220|76.105.133.220]] 16:09, 11 October 2013 (UTC)
: I visualize it as looking down on Earth, with the "shadow" of the celestial object on top of the M25/soccer field/laptop/etc. [[Special:Contributions/67.51.59.66|67.51.59.66]] 17:02, 11 October 2013 (UTC)

Has anyone noticed that Voyager 1 and 2 look like viruses? Kind of funny considering they're next to E. Coli...
[[User:StelarCF|StelarCF]] ([[User talk:StelarCF|talk]]) 17:54, 11 October 2013 (UTC)

: Yeah, I thought that too. It's a happy thought. Why, you ask? Well, with vastly diminished (or - in the course of time - zero) output from RTG power sources, they're like weakened (or inactivated) viruses - that we've sent out to the rest of the Universe, to any other intelligent lifeforms that may find them. What does that remind you of?

: VACCINES! We've vaccinated aliens to the human condition :D To the Earthly condition even.

: [PS - that's a happy thought because I choose to interpret from a cross-contamination standpoint. Which, in this case, allows them to observe us in our own locale, and establish our intrinsic nature - before a two-way interaction with us, in 'shared space' :P, and observing us through the medium of those interactions.] [[Special:Contributions/220.224.246.97|220.224.246.97]] 18:46, 11 October 2013 (UTC)

Does "Explain XKCD" installation of MediaWiki has [http://www.mathjax.org/ MathJax] [plugin] installed for writing mathematics formulas? --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 08:15, 12 October 2013 (UTC)

Too bad he didn't do the Pleiades. I mean, instead of using the Vatican, he could have used something geeky: Bletchley Park or something (though that's probably not big enough). [[User:Homunq|Homunq]] ([[User talk:Homunq|talk]]) 14:11, 12 October 2013 (UTC)

Talk:1276: Angular Size

2013-10-13T12:33:50Z

Wilberforce: changed IP signature to real

What is the meaning of "football field" in panel #2? --[[User:Kevang|Kevang]] ([[User talk:Kevang|talk]]) 04:50, 11 October 2013 (UTC)
:I was wondering the same thing. Probably misplaced text. [[User:Irino.|Irino.]] ([[User talk:Irino.|talk]]) 05:49, 11 October 2013 (UTC)
::It does seem to be misplaced, but if that's the only glitch, this is the only panel without a unique reference object. "20 football pitches long" isn't all that easy to grasp. [[User:Jameslucas|jameslucas]] ([[User talk:Jameslucas|" "]] / [[Special:Contributions/Jameslucas|+]]) 09:09, 11 October 2013 (UTC)
:::The image is fixed by Randall. I did an update here.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 11:28, 11 October 2013 (UTC)
::::Well, that's a letdown. I'm surprised Randall didn't use Heathrow. [[User:Jameslucas|jameslucas]] ([[User talk:Jameslucas|" "]] / [[Special:Contributions/Jameslucas|+]]) 13:42, 11 October 2013 (UTC)

I haven't done any lookups or maths to check these, but give the size of these as "stars" in the sky, everything from panel 2 onwards seems to me to be an order of magnitude or two too large. [[User:Markhurd|Mark Hurd]] ([[User talk:Markhurd|talk]]) 05:17, 11 October 2013 (UTC)
: Not really. You see the stars and planets as points because their angular size is lower than your eyes' resolution. They have measurable (or, in case of really distant or small objects, computable) angular sizes. For stars etc. these angular sizes are really small - but Earth is quite big, so if you cut a portion of a sphere the radius of Earth corresponding to these small solid angles, you get sizable areas. I haven't checked Randall's math, but I'd rather believe his results. If it is non-intuitive for you consider the Sun and Moon example - when observed by naked eye, the Moon looks for you as being the size of a dime held up in your hand - and yet it's shadow during an eclipse covers quite an area of Earth's surface. It is true that sizes of some of these "footprints" are quite surprising compared to other ones. [[Special:Contributions/89.174.214.74|89.174.214.74]] 08:55, 11 October 2013 (UTC)
:: Definitely surprising. I'll put faith in Randall doing his math correctly, but still needed to check on a couple of these because they did elicit a "What? No. Really? Can't be." reaction. Using the formula described in the Explanation above, for Venus I get 12742 km (Earth radius) * 12104 km (Venus diameter) / 38000000 (shortest distance to Venus) = 2.03 km.
:: Hard to picture that something that is such a small dot in the sky is actually directly over such a large patch of ground. But there you are.
[[Special:Contributions/67.51.59.66|67.51.59.66]] 17:11, 11 October 2013 (UTC)
::: The question that sprung to my mind was, ''which'' distance is he using for the planets and asteroids, since those vary hugely depending on where objects are relative to each other along their orbits. Is he going with closest approach, maybe? Or the distance that we happen to be at just this instant? --[[User:Rmharman|Rmharman]] ([[User talk:Rmharman|talk]]) 21:42, 11 October 2013 (UTC)

Does someone know how to use LaTeX formulas? And if so, can they translate my formula into something more pleasing to the eye? [[User:Irino.|Irino.]] ([[User talk:Irino.|talk]]) 05:49, 11 October 2013 (UTC)

According to the wikipedia page, the M25 is 117 miles long. That sounds more like "37 miles across" to me. [[User:Kaa-ching|Kaa-ching]] ([[User talk:Kaa-ching|talk]]) 08:46, 11 October 2013 (UTC)
: it originally stated 15 miles, someone has fixed it now. Thanks! [[User:Kaa-ching|Kaa-ching]] ([[User talk:Kaa-ching|talk]]) 11:35, 11 October 2013 (UTC)

Neither the sun or moon, nor Messier 25 (declination -19°) can ever culminate in the zenith over London. :-( Admittedly, Townsville, Australia would be sort of overwhelmed by M25. --[[Special:Contributions/129.13.72.198|129.13.72.198]] 11:27, 11 October 2013 (UTC)
: M25 is a reference to the highway that surrounds London, not the Messier object, which is probably nowhere near the angular size of the moon. [[Special:Contributions/65.129.214.100|65.129.214.100]] 15:17, 11 October 2013 (UTC)
::Why would Randall choose London, if it wasn´t for the obvious disambiguity of the name M25? ----[[User:Wilberforce|Wilberforce]] ([[User talk:Wilberforce|talk]]) 12:33, 13 October 2013 (UTC)

Does anyone know why the exoplanet "HD 189733 b" is labled as "Permadeath" ? Same question for the other weird names in the same pannel (the "tilde on keyboard" one) ? [[User:Jahvascriptmaniac|Jahvascriptmaniac]] ([[User talk:Jahvascriptmaniac|talk]]) 11:32, 11 October 2013 (UTC)
: A reference to [[1253|Exoplanet Names]]. [[User:Squornshellous Beta|Squornshellous Beta]] ([[User talk:Squornshellous Beta|talk]]) 12:08, 11 October 2013 (UTC)

If you were looking from the center of the earth, as the situation suggests, wouldn't the M25 be reversed, east-to-west, as you look at the sun and the moon?--[[Special:Contributions/76.105.133.220|76.105.133.220]] 16:09, 11 October 2013 (UTC)
: I visualize it as looking down on Earth, with the "shadow" of the celestial object on top of the M25/soccer field/laptop/etc. [[Special:Contributions/67.51.59.66|67.51.59.66]] 17:02, 11 October 2013 (UTC)

Has anyone noticed that Voyager 1 and 2 look like viruses? Kind of funny considering they're next to E. Coli...
[[User:StelarCF|StelarCF]] ([[User talk:StelarCF|talk]]) 17:54, 11 October 2013 (UTC)

: Yeah, I thought that too. It's a happy thought. Why, you ask? Well, with vastly diminished (or - in the course of time - zero) output from RTG power sources, they're like weakened (or inactivated) viruses - that we've sent out to the rest of the Universe, to any other intelligent lifeforms that may find them. What does that remind you of?

: VACCINES! We've vaccinated aliens to the human condition :D To the Earthly condition even.

: [PS - that's a happy thought because I choose to interpret from a cross-contamination standpoint. Which, in this case, allows them to observe us in our own locale, and establish our intrinsic nature - before a two-way interaction with us, in 'shared space' :P, and observing us through the medium of those interactions.] [[Special:Contributions/220.224.246.97|220.224.246.97]] 18:46, 11 October 2013 (UTC)

Does "Explain XKCD" installation of MediaWiki has [http://www.mathjax.org/ MathJax] [plugin] installed for writing mathematics formulas? --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 08:15, 12 October 2013 (UTC)

Too bad he didn't do the Pleiades. I mean, instead of using the Vatican, he could have used something geeky: Bletchley Park or something (though that's probably not big enough). [[User:Homunq|Homunq]] ([[User talk:Homunq|talk]]) 14:11, 12 October 2013 (UTC)

1276: Angular Size

2013-10-13T12:31:56Z

Wilberforce: /* Explanation */ don´t tell me im the first to spot this.

{{comic
| number = 1276
| date = October 11, 2013
| title = Angular Size
| image = angular size.png
| titletext = If the celestial sphere were mapped to the Earth's surface, astronomy would get a LOT easier; you'd just need a magnifying glass.
}}

==Explanation==
{{incomplete}}
This comic is a comparison of the {{w|angular diameter|angular diameters}} (or apparent diameter) of various celestial objects at the surface of the earth relative to a vertex at the center of the Earth as diagrammed in the opening panel. The objects' scales are compared to actual objects on earth for comparison. Each size given is for the object at its closest approach to earth.

London's {{w|M25 motorway}} is around 60 km (35 miles) across, a {{w|soccer field}} is about 100 meters long, a {{w|Table tennis table|ping pong table}} is 274 centimeters long, a {{w|laptop}} is about 35 centimeters across, the {{w|tilde}} symbol on a keyboard is about 5 millimeters long, and a cell of ''{{w|Escherichia coli|E. coli}}'' is about 2 micrometers long.

A simple {{w|Intercept theorem|formula}} can be used to find the size on earth of a celestial object when the size of and distance to the object is known. This is done by taking the radius of the earth, multiplying by the diameter of the object, and dividing by the distance to the object from the center of the earth.

The space objects referenced in the panels are:

* The {{w|Sun}} and the {{w|Moon}}, and also the open cluster {{w|Messier 25}}, have approximately the same size (around 0.5 degrees of arc) when seen from the Earth.

* {{w|Mercury (planet)|Mercury}}, {{w|Venus}}, {{w|Mars}}, {{w|Jupiter}}, {{w|Saturn}}, {{w|Uranus}}, and {{w|Neptune}} are the other planets of the {{w|Solar System}}.

* {{w|Io (moon)|Io}}, {{w|Europa (moon)|Europa}}, {{w|Ganymede (moon)|Ganymede}}, and {{w|Callisto (moon)|Callisto}} are the main moons of Jupiter; {{w|Titan (moon)|Titan}} is the largest moon of Saturn; and {{w|Triton (moon)|Triton}} is the largest moon of Neptune. {{w|Ceres (dwarf planet)|Ceres}} and {{w|Pluto}} are {{w|dwarf planet}}s.

* {{w|Phobos (moon)|Phobos}} and {{w|Deimos (moon)|Deimos}} are the moons of Mars. {{w|Eris (dwarf planet)|Eris}} is another dwarf planet. {{w|R Doradus}} and {{w|Betelgeuse}} are giant stars, respectively around 180 and 640 light-years away. R Doradus is the star with the largest apparent diameter (other than the sun, of course).

* {{w|4942 Munroe}} is an asteroid [http://blog.xkcd.com/2013/09/30/asteroid-4942-munroe/ named] after xkcd author [[Randall]] Munroe. {{w|Proxima Centauri}}, {{W|Alpha Centauri|Alpha Centauri AB}}, {{w|Barnard's star}} and {{w|Sirius}} are nearby stars (all within 10 light-years from the Sun).

* {{w|HD 189733 b}}, {{w|Gliese 581 b}}, {{w|Gliese 667 Cc}}, {{w|82 G. Eridani#Planetary_system|HD 20794 c}}, {{w|Tau Ceti#Planets|Tau Ceti c}}, and {{w|KOI-1686.01}} are {{w|extrasolar planet}}s; the parenthetical names are references to the comic [[1253: Exoplanet Names]]. However, some of the planets' parenthetical names do not match the table in the previous comic. For example, HD 20794 c is called "Legoland" rather than "Moonchild" in [[1253: Exoplanet Names]]. The {{w|black hole}} at the center of our Galaxy is {{w|Sagittarius A*}}, a massive object containing a mass more than 4 million times of our Sun.

* {{w|Voyager 1}} and {{w|Voyager 2|2}} are space probes launched in 1977, and currently around 125 and 100 {{w|astronomical unit}}s away, respectively.

The title text is about astronomy would be much easier if the celestial sphere were mapped to the earth, should come as no surprise; essentially, it's equivalent to asking "what if the earth were a giant telescope." That is, although there's no actual optical setup which would enable such a mapping, an earth so mapped would be functioning as a giant telescope.

Approximate values for the mappings to the Earth sphere (based on mean Earth radius at 6,371.0 km):
{| class="wikitable sortable"
|-
! Panel
! Object
! Distance
! Diameter
! Size at Earth sphere
|-
| rowspan="4"| Panel 1
|| Sun
|| 149,600,000 km
|| 1,392,684 km
|| 59.3 km
|-
|| Moon Semi-major axis
|| 384,399 km
|| 3,476.28 km
|| 57.6 km
|-
|| Moon Perigee
|| 363,295 km
|| 3,476.28 km
|| 60.9 km
|-
|| Messier 25
|| 2100 ly
|| 19 ly
|| 57.6 km
|-
| rowspan="7"| Panel 2
|| Mercury closest approach
|| 92 million km
|| 4,879.4 km
|| 0.34 km
|-
|| Venus closest approach
|| 41 million km
|| 12.103.6 km
|| 1.9 km
|-
|| Mars closest approach
|| 56 million km
|| 6,792.4 km
|| 0.77 km
|-
|| Jupiter
|| 778,547,200 km
|| 139,822 km
|| 1.14 km
|-
|| Saturn
|| 1,433,449,370 km
|| 120,536 km
|| 0.54 km
|-
|| Uranus
|| 2,876,679,082 km
|| 51,118 km
|| 0.11 km
|-
|| Neptune
|| 4,503,443,661 km
|| 49,528 km
|| 0.07 km
|-
| rowspan="8"| Panel 3
|| Io
||
||
||
|-
|| Europa
||
||
||
|-
|| Ganymede
||
||
||
|-
|| Callisto
||
||
||
|-
|| Titan
||
||
||
|-
|| Triton
||
||
||
|-
|| Ceres
||
||
||
|-
|| Pluto
||
||
||
|-
| rowspan="5"| Panel 4
|| Phobos
||
||
||
|-
|| Deimos
||
||
||
|-
|| Eris
||
||
||
|-
|| Betelguse
||
||
||
|-
|| R. Doradus
||
||
||
|-
| rowspan="6"| Panel 5
|| 4942 Munroe
||
||
||
|-
|| Proxima Centauri
||
||
||
|-
|| Bernard's Star
||
||
||
|-
|| Alpha Centauri B
||
||
||
|-
|| Sirius
||
||
||
|-
|| Alpha Centauri A
||
||
||
|-
| rowspan="7"| Panel 6
|| HD 189733 b
||
||
||
|-
|| Gliese 581 g
||
||
||
|-
|| Black Hole at the center of our Galaxy
||
||
||
|-
|| Gliese 667 Cc
||
||
||
|-
|| HD 20794 c
||
||
||
|-
|| Tau Ceti C
||
||
||
|-
|| Koi-1686.01
||
||
||
|-
| Panel 7
|| Voyager probes
||
||
||
|}

==Transcript==
{{incomplete transcript}}

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