Main Page
Welcome to the explain xkcd wiki!
We have an explanation for all 3221 xkcd comics, and only 69 (2.1%) are incomplete. Help us finish them!
Latest comic
| Little Red Dots |
 Title text: After a lot of analysis, I've determined that they're actually big red dots; they're just very far away. |
Explanation
The little red dots that the comic refers to are something of an astronomical mystery, discovered by the JWST telescope. They may be powered by very, very old black holes from 400-700 million years after the Big Bang, with the light from when they were young. The comic purports to give the responses of several different experts in unrelated fields when asked to identify them:
- According to the entomologists (scientists who study insects and related arthropods), they are clover mites (Bryobia praetiosa) — very small red arachnids.
- According to the computer scientists, they are stuck pixels — pixels that do not work properly, and are stuck to one single color (red in this case). This is a plausible concern, but presumably should already be handled through calibration processes.
- According to the dermatologists (doctors who specialize in skin disorders), they are cherry angiomas — harmless, non-cancerous skin growths made of clusters of dilated capillaries, appearing as bright red, smooth, or slightly raised spots.
- According to the graphic designers, they are colors of type Jasper (● #d73b3e) or Vermillion (● #e34234, sometimes called Cinnabar).
Quite obviously, all of these, if not completely incorrect, are fully unrelated to astronomy.
Part of the punchline is the shift in focus: instead of trying to identify the object, the designer is nitpicking the description of "red dot." Additionally, the graphic designer is also requesting Cueball's color settings, implying they believe the reason Cueball calls them "red" is due to poor display settings, and not due to using the common term for the color. There is a certain amount of insight here, as the JWST only observes orange to far-infrared light; this is to enable it to see very distant objects, whose blue and ultraviolet emissions have been redshifted into longer wavelengths. Converting observed wavelengths into rest-frame wavelengths is a process subject to error, and then falsely-coloring the object so that it may be visualized by human eyes is another such.
In the title text, Randall claims to have analyzed the "little red dots" and determined that they are actually very large but distant objects. This is, however, an obvious deduction, since the JWST telescope is only ever used to look at very distant objects in space[citation needed], and these 'dots' must therefore be very large just to be visible at all (due to the phenomenon of relative perceived size, where larger objects that are further away appear to be the same size as smaller ones that are closer to the viewer). The punchline here is that someone who has performed a lot of analysis would be expected to have a result that was not already obvious, but anyone looking at a telescope image of deep space would already be assuming that it depicts large objects very far away, not small objects close to the telescope.
The (possible) issue of a 'stuck pixel', except of a different hue, was previously visited in 1246: Pale Blue Dot.
Transcript
- [Caption above all the panels:]
- Astronomers asking researchers from different departments to help them identify the "little red dots" in JWST images:
- [In each panel, Cueball stands at the left of an easel. The easel is shown each time as having a black image with three red dots on it. At the right of the easel in each panel is a different character looking at the image on the easel and commenting on it. At the top of each panel is a caption indicating the type of researcher commenting on the image.]
- Caption: Entomologists
- Megan: Clover mites.
- Caption: Computer scientists
- Knit Cap: Stuck pixels.
- Caption: Dermatologists
- Ponytail: Cherry angiomas.
- Caption: Graphic designers
- Hairy: No, those are vermillion, or maybe jasper.
- Hairy: Can I see your color settings?
View comic discussionNew here?
Last 7 days (Top 10) |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
You can read a brief introduction about this wiki at explain xkcd. Feel free to create an account and contribute to the wiki! We need explanations for xkcd comics, characters, What If? articles, and everything in between. If it is referenced in an xkcd comic, it should be here.
- If you're new to wiki editing, see the explain xkcd:Editor FAQ for a specific guidance to this wiki and the more general help on how to edit wiki pages. There's also a handy wikicode cheatsheet.
- Discussion about the wiki itself happens at the Community portal.
- You can browse the comics from the list of all comics or by navigating the category tree at Category:Comics.
- The incomplete explanations are listed here. Feel free to help out by expanding 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 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 who repeatedly post such content will be blocked.
If you need assistance from an admin, post a message to the Admin requests board.
