Locke and Demosthenes
by Mike
Image Text: Dear Peter Wiggin: This letter is to inform you that you have received enough upvotes on your reddit comments to become president of the world. Please be at the UN tomorrow at 8:00 sharp.
This comic references the Orson Scott Card novel Ender's Game. [SPOILER] In it, Ender's higher-than-average intelligence siblings, Valentine Wiggin and Peter Wiggin decide to make a move for power on earth by posting contrasting opinions of the Formic War on their version of the internet. They used the pseudonyms Locke and Demosthenes respectively and eventually coerced the trust of the entire planet by playing their posts against each other. This lead to Peter gaining control of the free world.
[EXTRA SPOILER] Peter is a borderline sociopath and kills that squirrel.
Wings
by Jeff
Image meta text: Please do not try any of this and die or get arrested.
This comic references Titan, a moon of Saturn which has 14% of earth's gravity. Because the gravity is less, it takes less lift to fly on Titan.
Also, the main character uses hot glue on his wings, similar to how Icarus of Greek Mythology flew too close to the sun with wings made of wax. Just like Icarus, the character falls after subjected to high levels of heat. In the comic's case, the heat was applied by a heat lamp from xkcd's resident troublemaker "Black Hat".
Asteriod
by Jeff
Image meta text: My Deep Impact/Little Prince crossover fanfic has been poorly received by the community.
Deep Impact is a motion picture from 1998 in which the protagonists have to blow up a asteroid that is headed to Earth. The Little Prince is a book by Antoine de Saint-Exupéry in which the Little Prince's home was on an asteroid.
In the comic, The Little Prince's asteriod home is headed towards Earth and the Deep Impact part of the fanfic lands the nuclear robot on The Little Prince's home.
Threesome
by Jeff
Image meta text: I wanted us to try finding an approximate numeric solution, but noooo.
For the three body problem, it is a math and astronomy problem about the gravity interaction between 3 different "bodies". Scholarpedia has this about the problem. "The [three body] problem is to determine the possible motions of three point masses m_1, m_2, and m_3, which attract each other according to Newton's law of inverse squares. ... While the two-body problem is integrable and its solutions completely understood, solutions of the three-body problem may be of an arbitrary complexity and are very far from being completely understood."
And obviously, with a threesome, there is literally three bodies. The comic is making a pun on that.
Kepler
by submission
Image text: Science joke. You should probably move along
This comic provided by Rik 't Hoff. http://www.facebook.com/profile.php?id=516678350
“Kepler” refers to Johannes Kepler, a German mathematician, astronomer and astrologer, best known for his laws of planetary motion. By observing our solar system each night at the same spot, Kepler was able to deduct that planets in the system do not move in a circular direction around the Sun, but rather in an oval way. As you can imagine, this observation was very monotone, and very time-consuming. Hence, if Kepler would have been a cleaner, he'd work consistent and “sweep” the same “area” every night.