Tensile vs. Shear Strength
by Jeff
Image text: Although really, the damage was done when the party planners took the hole punch to the elevator ribbon to hang up the sign.
The Space Elevator is an idea about how to quickly move ships, people and supplies into orbit without the
The Tower of Babel was an ancient building built so that it would be a testament to man's ability and would go so high, it would have its top among the heavens. This is why the comic is referencing a "modern Babel" because the space elevator would have its top among the stars.
Tensile Strength is the maximum load that a material can support without fracture when being stretched.
Shear strength is the maximum shear stress which a material can withstand without rupture. The comic is making a pun on this because the Black Hat character is using "shears" or scissors to cut the elevator ribbon.
This comic is also referencing how at a Grand Opening, there is a "ribbon cutting ceremony". In the comic, there is a "ribbon cutting ceremony", however, the ribbon that is cut is not the ceremonial ribbon, but the space elevator ribbon.
Spirit
by Jeff
Image text: On January 26th, 2213 days into its mission, NASA declared Spirit a 'stationary research station', expected to operational for several more months until the dust buildup on its solar panels forces a final shutdown.
The title of the comic is a pun on the word "Spirit" because the name of the Rover is Spirit and in the comic, the rover is showing almost unwavering spirit as it goes about its mission for six years.
Gravity Wells
by Jeff
Image text: This doesn't take into account the energy imparted by orbital motion (or gravity assists or the Oberth effect), all of which can make it easier to reach outer planets.
This is awesomely epic. Click the image to see the full image in detail.
Sagan-Man
by Jeff
Image text: They laugh now, but within 10 years the city's entire criminal class will have quit to work on space research.
Carl Sagan is an advocate for science, space and SETI (Search for Extra-Terrestrial Intelligence). He wrote the book, Contact, which was later made into the movie by the same name.
This comic is parodying Spiderman, in which Peter Parker is bitten by a radioactive spider to become Spiderman. In this comic a radioactive Carl Sagan turns the person into "Sagan-Man".
The Search
by Jeff
Image text: I am so excited about the Kepler mission. This is the second most important thing our species has ever done, right behind inventing the concept of delivery pizza.
The Kepler mission is a NASA-led research mission in which a telescope was launched into orbit around the sun. The focus of the telescope is to find other "Earth-like" planets that could sustain life.
The comic is saying that our search for life is as futile as the ants searching a dozen floor tiles in someone's kitchen. If those ants were in my kitchen, they wouldn't have to go far before finding my sentient life and feeling the wrath of my spray can of RAID.
Additionally, the Kepler Nasa site looks like it is from 1996.
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.