Map Projections
by Jeff
Image text: What's that? You think I don't like the Peters map because I'm uncomfortable with having my cultural assumptions challenged? Are you sure you're not ... ::puts on sunglasses:: ... projecting?
This comic is takes all the different map projections, which is the way that the sphere that is the Earth is placed into a flat map, and makes assumptions on what type of person prefers that type of map projections. Not much to explain here as the different types of map projections are laid out and all the text below the map projections are jokes.
In the image text, the joke here goes to the familiar meme from CSI:Miami, in which the star, David Caruso starts on sentence, then puts on his sunglasses and then ends it with a corny pun. Naturally, there is a youtube video that has collected all of these one liners. This internet meme has been mentioned previously by xkcd in comic 626 and possibly others.
Sail
by Jeff
Image text: It only works a few times before you have to capsize the boat in a soap lagoon again.
In this comic, over the first 3 frames, it seems like Cueball is piloting a normal sailboat. However, in frames 4-6, it becomes obvious, that Cueball is actually using bubble solution for his sail instead. When the sail gets enough wind, it creates its own bubble.
As the image text says, you have to submerge the boat in soap again to get enough soap on the sail to blow bubbles again.
Occulting Telescope
by Jeff
Image text: Type II Kardashev civilizations eventually completely enclose their planetary system in a Dyson sphere because space is way too big to look at all the time.
In this comic, Professor Cueball is suggesting an "Occulting Telescope", which follows directly with the definition of an occultation (thanks Wikipedia!) which is an event that occurs when one object is hidden by another object that passes between it and the observer. This telescope sees a star, then positions a disc between itself and the star, occulting itself and Earth from the light from the star.
The reasoning for this maneuver is that Professor Cueball thinks there are too many stars (as he says in the last frame).
In the image text, The Kardashev scale (thanks Wikipedia!) is a method of measuring an advanced civilization's level of technological advancement. The scale has three designated categories called Type I, II, and III. These are based on the amount of usable energy a civilization has at its disposal, and the degree of space colonization. In general terms, a Type I civilization has achieved mastery of the resources of its home planet, Type II of its solar system, and Type III of its galaxy. One of the properties of a Kardashev type II civilization is the creation of a Dyson sphere around a planet to contain all its energy. And lastly, a Dyson Sphere (Wiki'ed!) is a hypothetical megastructure originally described by Freeman Dyson. Such a "sphere" would be a system of orbiting solar power satellites meant to completely encompass a star and capture most or all of its energy output.
This comic's image text says that the secondary benefit from a Dyson sphere is that it obscures (or completes the occultation of) all those pesky stars.
The General Problem
by Jeff
Image text: I find that when someone's taking time to do something right in the present, they're a perfectionist with no ability to prioritize, whereas when someone took time to do something right in the past, they're a master artisan of great foresight.
So, this comic is not at all about the salt. Crazy, I know! This is a lot about computer science, programming or other ways you can set up systems to do repeatable tasks. In the comic, instead of passing the salt, the person outside of the frame is building a system (mechanically?) to pass any condiment for the future. And as the image text says, they look like a perfectionist with no ability to prioritize, but the next time Cueball asks for a condiment and the system immediately passes it, they will look like (from the image text) a master artisan of great foresight.
MTV Generation
by Jeff
Image text: If you identified with the kids from The Breakfast Club when it came out, you're now much closer to the age of Principal Vernon.
This one is pretty straightfoward, so let's just do some definitions.
MTV is Music Television, it is a TV channel is the US and elsewhere that when it started in the 1980s used to show music videos. Now it only shows crappy reality TV.
The Breakfast Club is an iconic movie from 1985 in which 5 very different teenagers spend a Saturday detention together at the school. Principal Vernon was obviously, the principal in the movie and was the overseer of the detention.
This comic is one of the rare appearances of the White Hat character, who is seen much less than the Black Hat character.
November
by Jeff
Image text: November marks the birthday of Charles Schulz, pioneer of tongue awareness.
This comic is an homage to Charles Schulz the creator of the comic Peanuts, who was born on November 26, 1922. Here's the comic in question by Schulz with Black Hat playing the Linus role, in a way and Cueball, the Lucy role. In both comics, when you start thinking about your tongue, you can't stop thinking about it. Similar in the way that if you start thinking about your breathing, you stop breathing unless you consciously think to breathe.
(ed note: And now I can't stop thinking about my tongue and have to think to breathe...)
This link also indicates that Schulz's comic is not completely about tongue awareness, instead has deeper meaning about one's existence in the world.
Alternative Literature
by Jeff
Image text: I just noticed CVS has started stocking homeopathic pills on the same shelves with--and labeled similarly to--their actual medicine. Telling someone who trusts you that you're giving them medicine, when you know you’re not, because you want their money, isn’t just lying--it’s like an example you’d make up if you had to illustrate for a child why lying is wrong.
This comic means nothing without the image text, so make sure you read it. Well, not nothing, but the image text gives it context.
Homeopathy is scientifically similar to a placebo because the medicine is so diluted. Xkcd has worked on this subject before, here's comic 765.
In this comic, the money quote in the actual comic that is not about books but about medicine is "Holding a book prompts the mind to enrich itself".
The Important Field
by Jeff
Image text: I hear in some places, you need one form of ID to buy a gun, but two to pay for it by check. It's interesting who has what incentives to care about what mistakes.
This comic is a commentary on how serious websites take the email address form, in this case to the ridiculous, asking for your email address twice to prevent a mistype, but only asking for the missile target coordinates once. Lots of websites make you type your email address twice, because having your correct email address is very valuable to these companies so they can send you "exclusive offers" and other spam to get you to buy things.
I'm not sure whether or not the claim in the image text is correct, can any one verify?
Delta-P
by Jeff
Image text: If you fire a Portal gun through the door of the wardrobe, space and time knot together, which leads to a frustrated Aslan trying to impart Christian morality to the Space sphere.
This comic was posted late and now I'm late and I'm at work so I can't do as much explaining as I usually do, but I'll do my best. That's also why we have the best comment section on the Internet.
The basic idea of the formula and the comic are based on the books and movies of the Lion, the Witch and the Wardrobe in which a giant wardrobe contains a portal to a world known as Narnia. In the comic, someone connects an anchor to the wardrobe and throws it into the ocean which means that a steady stream of water at a velocity of 200 m/s will flow into Narnia.
The White Witch, the antagonist in the books and movies apparently won't know what hit her according to the caption.
The image text references the video game "Portal" in which you fire a portal gun into walls and etc to make "portals" that can open holes in other places so that you may portal through.
The image text also references the fact that CS Lewis wrote the Lion, Witch and Wardrobe books as a thinly veiled allegory of Christ's crucifixion with Aslan, the Lion in the title, playing Christ's part. (Spoiler alert! Sorry!)
This is a classic xkcd based on the intersection of literature, math and video games.
Everything
by Jeff
Image text: I wanna hold your hand so I don't fall out of your gyrocopter.
In this comic, the first three sentences are a bunch of statements that you would find in a birthday or anniversary card from one person in a relationship to another. In this case, all the statements are in the negative. However, by the last frame, a positive greeting card statement is used, but is continued below, which makes it less of a greeting card statement and more match up with what is going on in the background.
In the background, Cueball is gathering a lot of different sort of random things, including a crane, what appears to be a bomb and the top of a manikin. He takes two more piles of stuff and creates some sort of super tank with huge wheels, a mounted gun, satellite dish and crane. It appears to be running as there is exhaust coming out of the top of the machine.
In the image text, a gyrocopter is a very small ultralight helicopter.
UPDATE: Thanks to the commentors, I missed the outline of a female character on the tank in the last frame. So take what I've said up there and reverse it. Cueball is the character speaking, not some separate 3rd party about Cueball.