3185: Sauropods

2025-12-26T11:08:45Z

Tyylk: /* Explanation */

{{comic
| number = 3185
| date = December 24, 2025
| title = Sauropods
| image = sauropods_2x.png
| imagesize = 317x424px
| noexpand = true
| titletext = Vertebrae Georg
}}

==Explanation==
{{incomplete|This page was created by an explainxkcd user who created 3184 pages. Don't remove this notice too soon.}}

This comic attempts to correct people on the skeletal structure of {{w|sauropod}} dinosaurs, claiming that most individuals actually had short necks and tails, and the "queen" of the colony had an enormous number of vertebrae, possibly resembling a snake with legs. The idea is that paleontologists misconstructed the skeletons, averaging the vertebrae out between all specimens, instead of giving most of them a single queen.

In reality, most of the animal species that have {{w|eusociality|colonies with queens}} are fairly small insects, particularly termites, ants, bees, and wasps; with {{w|naked mole-rat}}s as a famous exception. No sauropods or other reptiles are known to do so. Also, while queens are often larger specimens than their workers or drones, they always share the same general anatomy. The comic suggests however that regular sauropods have a vastly different anatomy than their supposed queens.

Additionally, it is obviously impossible that a single sauropod could have a neck anywhere near that long; it would collapse under its own weight. Insead, the comic shows it looping around several times without issue. In fact, (all) sauropods already have substantial skeletal adaptations just to accommodate their {{w|sauropoda#Necks|elongated necks}}.

The title-text references {{w|Spiders Georg}}, an internet meme character who allegedly eats over 10,000 spiders a day, skewing the average, creating the factoid that "the average person swallows 3 spiders a year."

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}

:[Top panel: A sauropod with a normal long neck and tail, crossed out with a large red X.]
:[Bottom panel: Two sauropods with very short necks and tails, with a green check mark drawn in between and an eel-like supposed "sauropod queen" situated above them, who is predominantly composed of sauropod necks winding off both sides of the panel, with a single head and tip of the tail visible. The sauropod queen and the sauropod on the left look at each other.]
:[Caption below the comic:]
:Thanks to modern paleontological reconstructions, we now know that most sauropods had short necks, and all those extra vertebrae belonged to the sauropod colony's queen.

{{comic discussion}}<noinclude>

[[Category:Biology]]
[[Category:Dinosaurs]]
[[Category:Comics with color]]

2561: Moonfall

2024-12-06T07:10:16Z

Tyylk: /* Realistic analysis of the scenario */

{{comic
| number = 2561
| date = December 29, 2021
| title = Moonfall
| image = moonfall.png
| titletext = Novel ideas and cool explosions are both good, but what I really want from a movie is novel ideas ABOUT cool explosions.
}}

==Explanation==
[[Megan]] asks [[Cueball]] if he is excited for the release of the movie ''Moonfall''.

''{{w|Moonfall (film)|Moonfall}}'' was released in February 2022, a couple of months after this comic. Its director, {{w|Roland Emmerich}}, is known for blowing up things in his movies (see for instance [https://www.gq.com/video/watch/explosions-the-roland-emmerich-supercut the Roland Emmerich Supercut]), as well as for factual inaccuracies in his work (mainly the scientific implausibility of his many disaster movies like ''{{w|Independence Day (1996 film)|Independence Day}}'', ''{{w|The Day After Tomorrow}}'' and ''{{w|2012 (film)|2012}}'').

The [https://www.imdb.com/title/tt5834426/plotsummary basic premise] of ''Moonfall'' is that a mysterious force manages to knock the moon out of its orbit, leaving it on a collision course with the Earth. This is scientifically preposterous (see [[#Realistic analysis of the scenario|analysis]] below), making it potentially 'cringe-worthy' for someone who prefers {{w|hard science fiction}} where things are more grounded in established scientific facts and theories. Cueball states that a story based on good science can potentially serve as a novel window into what the real world may look like someday—or, as he puts it, "expand our ideas of what's possible."

But Cueball then goes on to imply that he's still looking forward to the movie because his less critical side is still excited by things like cool spaceship noises and smashing moons into things. Sometimes you just want to [[311: Action Movies|get lost in mindless action]], even if it's less 'mature' than a well-thought-out meaningful plot. Megan then sums things up by playing off Cueball's wording from the previous panel, saying she's excited to "expand our ideas on how much stuff can explode at once." Given the scale of ''Moonfall'''s premise involving a potential planetary-scale collision, as well as the director's tendency to use gratuitous visual effects and explosions in his movies, it seems reasonable to conclude that the movie will likely contain quite a lot of stuff exploding at once.

In the title text Cueball continues by explaining that while novel ideas and cool explosions are good, what he really wants from a movie is novel ideas about cool explosions. So new ways to explode things, or ideas about exploding more things at once. Or both!

[[1536: The Martian]] contains a similar discussion of an (at the time) upcoming movie, in particular ''{{w|The Martian (film)|The Martian}}''. In that case, however, the subject of the comic was the movie's high scientific accuracy and lack of huge explosions, rather than the other way around.

===Realistic analysis of the scenario===
For the moon to fall from the sky, it would have to stop orbiting. Most forces applied it to will simply change the way in which it is orbiting, making the orbit more elliptical, larger or smaller. To stop it from orbiting entirely, a 'braking' force would need to be applied in the opposite direction of its travel, to halt it.

The moon's mass is about 7.34767×1022 kg and its speed about 1.022 km/s, so the energy needed to stop it is ½''mv''2 or about 3.8364×1028 joules. That's about the energy of 1 trillion large nuclear explosions, centered on the leading-most point of the moon's surface. In theory, a precisely-oriented stellar body could strike the moon to do this, for example, if something the mass of Ceres impacted at 16km/s. This would be dramatic. {{Citation needed}} It would, however, be below the Moon's gravitational binding energy, which, since the Moon is densest near its center, is much greater than 3Gm2/5r = 1.2x1029 joules, so the Moon would not be immediately entirely destroyed. It is, however, about the right amount of energy to liquify the entire Moon, if it takes an average of 450kJ/kg to melt the lunar rock, then it comes out to 3.3×1028 J to liquify the Moon. Whatever the exact details of the impact are, it would be bad for the Moon, and it is implausible that it would result in the Moon falling into the Earth.

Less counteractive energy could make the Moon change orbit to one with a {{w|perigee}} below the surface of the Earth, close enough to (partially) enter the atmosphere or merely bring it down beneath the applicable {{w|Roche limit}}. These scenarios would be only technically less catastrophic, and whether the Moon fragments from the initially applied force, the stresses of its nearest (non-contact) distance to Earth or actually survives largely intact until there is a more direct physical interaction, the precise degree of the effect might be practically academic.

==Transcript==
:[Cueball and Megan walking to the right]
:Megan: Are you excited for ''Moonfall''?
:Megan: Or cringing?
:Cueball: Well...

:[Closeup on Cueball]
:Cueball: I like when stories are grounded in good science because it's exciting to expand our ideas of what's possible.

:[Zoomed back out to Cueball and Megan walking to the right. Cueball has his palms raised]
:Cueball: But I also support giving Roland Emmerich as much money as he wants to make cool spaceship noises and smash moons into things.
:Megan: Excited to expand our ideas of how much stuff can explode at once.

{{comic discussion}}

[[Category: Fiction]]
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring Megan]]
[[Category: Comics featuring real people]]

explain xkcd - User contributions [en]

3185: Sauropods

2561: Moonfall