Main Page

Explain xkcd: It's 'cause you're dumb.
(Difference between revisions)
Jump to: navigation, search
(Happily, we')
(fix count and add explanation)
Line 4: Line 4:
 
<center>
 
<center>
 
<big>''Welcome to the '''explain xkcd''' wiki!''
 
<big>''Welcome to the '''explain xkcd''' wiki!''
We already have [[:Category:Comics|'''{{#expr:{{PAGESINCAT:Comics}}-3}}''' comic explanations]]!</big>
+
We already have [[:Category:Comics|'''{{#expr:{{PAGESINCAT:Comics}}-10}}''' comic explanations]]!</big>
 +
<!-- Note: the -10 in the calculation above is to discount subcategories (there are 7 of them as of ~~~~~),
 +
    non-comic pages (2 as of same date: [[List of all comics]] and [[Exoplanet]])
 +
    and the comic 404, which was deliberately not posted. Thus 7 + 2 + 1 = 10 -->
  
(But there are still {{#expr:{{LATESTCOMIC}}-({{PAGESINCAT:Comics}}-3)}} to go. Come and [[List of all comics|add yours]]!)
+
(But there are still {{#expr:{{LATESTCOMIC}}-({{PAGESINCAT:Comics}}-10)}} to go. Come and [[List of all comics|add yours]]!)
 
</center>
 
</center>
  

Revision as of 16:59, 20 November 2012


Welcome to the explain xkcd wiki! We already have Expression error: Unrecognised punctuation character ",". comic explanations!

(But there are still Expression error: Unrecognised punctuation character ",". to go. Come and add yours!)

Latest comic

Go to this comic

Solar System Questions
My country's World Cup win was exciting and all, but c'mon, what if the players wore nylon wings and COULD LITERALLY FLY?
Title text: My country's World Cup win was exciting and all, but c'mon, what if the players wore nylon wings and COULD LITERALLY FLY?

Explanation

Ambox notice.png This explanation may be incomplete or incorrect: 1) Explain "in the wrong places" re: Io's volcanoes.

This comic is a list of questions which Randall has about the Solar System, which at first glance may appear to be things that Randall would like to learn about. In actuality, most of the questions have not been satisfactorily answered or proven by anyone in the scientific community.

Question given Answer given by Randall (in Red) Comments
Why is the the Moon so blotchy? Lava The Moon is in synchronous rotation with Earth, which means that we always can see only one half of the surface of the Moon. And on that side we can see large lunar maria formed by lava from big volcanoes. This surface is very different to all other celestial bodies we know in our Solar system. The double "the the" could be a Randallism — intended or unintended.
Why are all the blotches on the near side? ... The nearside of the Moon is dominated by the blotchy 'seas' or maria, the far side by craters. Several explanations for this have been proposed, including an overabundance of impacts obliterating the blotches on the more exposed far side, different compositions of heat-producing elements, large collisions, or heat produced by the still-cooling Earth.
Did Mars have seas? Yes (briefly?) Recent explorations have confirmed there was once standing (and also flowing) water on Mars. Many rovers and orbiters on Mars give us the evidence on this early development of that planet, but it is still unknown how long such conditions existed in its history.
Was there life on Mars? ... One of the big mysteries, not yet answered.
What's Titan like? Cold, yellow, lakes + rivers (methane) The Cassini–Huygens mission confirmed the presence of lakes and rivers on Titan. The Huygens lander itself returned some very yellow images of a dry lake bed from Titan's surface.
What was Earth like during the Hadean? ... The Hadean was the first geologic era on earth, the planet had just formed and not much is known of that period of Earth. But since it was the time when Earth was formed it was mainly very hot with extreme volcanic activity, with the entire surface melted. This is why the era is named after Hades the ancient Greek god of the underworld.
Is the Oort Cloud a real thing? ... The Oort Cloud is a theoretical spherical cloud of icy planetesimal, maybe dust, and also larger objects at a distance of up to around 100,000 AU to our Sun. We can see similar clouds at other stars, but there is still no evidence that this cloud exists in our Solar System.
Why is the Sun's corona so hot? Something about magnets? The corona of the sun is hotter than it theoretically should be. The looping magnetic fields in this area could be responsible.
What are comets like? Precipitous The Philae lander is next to a cliff...
Where's Philae, exactly? ... ...but we're not sure which cliff.
What's Pluto like? [Soon!] The probe New Horizons may be about to answer both of these questions, as it will reach its closest approach to both Pluto and Charon just eight days after the release of this comic.
What's Charon like?
Why don't we have in-between-sized planets? ... There is a size-gap between the rocky terrestrial planets up to Earth size and the gas giants very much larger than Earth in our Solar System.

There are many known exoplanets (planets in other solar systems) filling in the range between our rocky planets and our gas giants, known as Super-Earths

What's Ceres like? [Working on it!] The Dawn probe is currently exploring the dwarf planet Ceres and reveals unseen surface features.
Why is Europa so weird-looking and pretty? Ice over a water ocean Europa is a moon of Jupiter and the surface is basically thick pack ice covered in lineae.
Why is Io so weird-looking? Sulfur volcanoes (? in the wrong places?) The moon Io is also orbiting Jupiter and is close enough that tidal forces make it the most volcanic object in the solar system. The moon is mainly yellow but there a several other colors on the surface, for instance spots and streaks of bright red color that comes from sulfur which is ejected by the volcanoes.
Why are so many Kuiper Belt objects red? ... Many objects in the Kuiper Belt have a reddish hue. A possible explanation is that they are covered in organic molecules formed by the irradiation of their surface ices. The New Horizons probe might also shed light on this.
What are those spots on Ceres? ... The Dawn probe found some mysterious spots on the Ceres. These white spots are still not understood, but the mission is still running and we may figure out the source of the glowing white features.
What's in the seas under Europa's ice? ... The European ESA selected the mission Jupiter Icy Moon Explorer (JUICE) to Jupiter. The moon Europa is one target for that mission. But we have to wait, its launch target is 2022 and the arrival at Jupiter is planned for 2030. But that's not uncommon for missions like this, New Horizons or Rosetta did also travel approx. ten years to reach their target. And before such a mission can start many preparations have to be done.
Which of the other moons have seas? Several Depending on the definition of 'sea', other less obviously 'frozen water world' moons such as Ganymede may have subsurface oceans of liquid water or other substance liquid at the relevant temperature.
What are the big white things in Titan's Lakes? ... Lakes of Titan
What do Jupiter's clouds look like up close? ...
What's all that red stuff in the Great Red Spot? ... Great Red Spot
What's pushing the Pioneer Probes? Heat from the RTG Discussed as the Pioneer anomaly. RTG stands for Radioisotope Thermoelectric Generator.
What pushes spacecraft slightly during flybys? ... Several spacecraft experienced unexplained speed increases during Earth flybys. This is called the flyby anomaly.
Where are all the Sun's Neutrinos? Oscillating Solar neutrino problem
Why is there so much air on Titan? ... Titan has an atmospheric pressure 1.45 times that of Earth, but 1/7th of the surface gravity (that's less than Earth's own, practically airless, Moon). Hence the confusion! In fact, Titan actually has almost 20% more atmosphere (by mass) than Earth, and seven times more atmosphere across a given surface area!

Less influence from the more distant Sun probably helps retain more of the atmosphere's gasses (mostly nitrogen), and cryovolcanoes may replenish the methane fraction (which should by now have all been converted into the other hydrocarbons present) from subsurface reservoirs. But further studies are required to properly answer this question.

Why does the Kuiper Belt Stop? ... A reference to the Kuiper Cliff.
Why is Iapetus weird-colored? ... Iapetus is a moon of Saturn and has a white side and a dark side.
Why does Iapetus have a belt? ... Iapetus has a 13 km high ridge around most of the equator, and a number of 10 km high mountains where the ridge is interrupted.
What's the deal with Miranda? ... Miranda is the smallest of Uranus' five round satellites, and it's a bit rough around the edges and also has an unusually high orbital inclination that is difficult to explain. Also possibly a Firefly reference since Miranda is also the name of a planet in Serenity, a film basedion the Firefly TV series.
Did Uranus and Neptune change places? ... The Nice model is a theory of how our solar system formed, which suggested the possibility of Uranus and Neptune having swapped places before reaching their current positions. Work by Professor S. Desch also came to this result.
Did the Late Heavy Bombardment happen? ... Late Heavy Bombardment
Did life start before it? ... For some speculation on this topic, see [1].
Is Europa covered in Ice Spikes? ... Dr Daniel Hobley has put forward a theory that Jupiter's icy moon, Europa, has the right conditions to form ice spikes called penitentes of up to 10m in height.
Why haven't we built a big inflatable Extreme Sports Complex on The Moon? ... See, e.g., The Menace From Earth, a 1957 short story by Robert Heinlein.

The title text refers to the 2015 FIFA Women's World Cup which was won by USA a day before. The nylon wings and flying may be a reference to two passages from 3001: The Final Odyssey, one where Frank Poole tries out various wings while in an extremely low gravity environment, and one where he remarks while watching Swan Lake that Tchaikovsky could never have imagined a performance where the dancers were actually flying (due to aforementioned low gravity). This is also a reference to the last point on the list, because if we had such a stadium on the moon, maybe it would be possible to use such wings to make very long floating leaps.

Transcript

Questions I have
about the solar system
(some answered)
Why is the the Moon so blotchy? Lava
Why are all the blotches on the near side?
Did Mars have seas? Yes (briefly?)
Was there life on Mars?
What's Titan like? Cold, yellow, lakes + rivers (methane)
What was Earth like during the Hadean?
Is the Oort Cloud a real thing?
Why is the Sun's corona so hot? Something about magnets?
What are comets like? Precipitous
Where's Philae, exactly?
What's Pluto like? [Soon!]
What's Charon like?
Why don't we have in-between-sized planets?
What's Ceres like? [Working on it!]
Why is Europa so wierd-looking and pretty? Ice over a water ocean
Why is Io so weird-looking? Sulfur volcanoes (? in the wrong places?)
Why are so many Kuiper Belt objects red?
What are those spots on Ceres?
What's in the seas under Europa's ice?
Which of the other moons have seas? Several
What are the big white things in Titan's Lakes?
What do Jupiter's clouds look like up close?
What's all that red stuff in the Great Red Spot?
What's pushing the Pioneer Probes? Heat from the RTG
What pushes spacecraft slightly during flybys?
Where are all the Sun's Neutrinos? Oscillating
Why is there so much air on Titan?
Why does the Kuiper Belt Stop?
Why is Iapetus weird-colored?
Why does Iapetus have a belt?
What's the deal with Miranda?
Did Uranus and Neptune change places?
Did the Late Heavy Bombardment happen?
Did life start before it?
Is Europa covered in ice spikes?
Why haven't we built a big inflatable
extreme sports complex on the moon?


New here?

Feel free to sign up for an account and contribute to the explain xkcd wiki! We need explanations for comics, characters, themes, memes and everything in between. If it is referenced in an xkcd web comic, it should be here.

  • List of all comics contains a complete table of all xkcd comics so far and the corresponding explanations. The red links (like this) are missing explanations. Feel free to help out by creating them!

Rules

Don't be a jerk. There are a lot of comics that don't have set in stone explanations, feel free to put multiple interpretations in the wiki page for each comic.

If you want to talk about a specific comic, use its discussion page.

Please only submit material directly related to—and helping everyone better understand—xkcd... and of course only submit material that can legally be posted (and freely edited.) Off-topic or other inappropriate content is subject to removal or modification at admin discretion, and users posting such are at risk of being blocked.

If you need assistance from an admin, feel free to leave a message on their personal discussion page. The list of admins is here.

Explain xkcd logo courtesy of User:Alek2407.

Personal tools
Namespaces

Variants
Actions
Navigation
Tools

It seems you are using noscript, which is stopping our project wonderful ads from working. Explain xkcd uses ads to pay for bandwidth, and we manually approve all our advertisers, and our ads are restricted to unobtrusive images and slow animated GIFs. If you found this site helpful, please consider whitelisting us.

Want to advertise with us, or donate to us with Paypal?