explain xkcd - User contributions [en]

Talk:2418: Metacarcinization

2021-01-30T04:35:48Z

162.158.111.185:

Up until the moment I opened the video, I read every instance of "crow" in the comic and explanation as "cow"... Was a bit disappointed by the video! [[Special:Contributions/141.101.105.40|141.101.105.40]] 19:39, 29 January 2021 (UTC)

I think the crow in the video is actually a hooded crow (Corvus cornix) rather than a jackdaw... [[Special:Contributions/108.162.245.146|108.162.245.146]] 20:39, 29 January 2021 (UTC)

Good catch. [[Special:Contributions/172.68.129.134|172.68.129.134]] 20:58, 29 January 2021 (UTC)

I think the crow in the video needs more training. Seems she's not really sure how the sledding works. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 01:04, 30 January 2021 (UTC)

Coincidentally, I just heard about a pet/tame duck (called 'Duck') who is regularly bodysurfing with their human in Australia. No idea where crabs come into that. They've probably been eaten by the sharks, or poisoned/envenomated by almost every other creature in and around Australia. [[Special:Contributions/162.158.111.185|162.158.111.185]] 04:34, 30 January 2021 (UTC)

Talk:2418: Metacarcinization

2021-01-30T04:34:23Z

162.158.111.185:

Up until the moment I opened the video, I read every instance of "crow" in the comic and explanation as "cow"... Was a bit disappointed by the video! [[Special:Contributions/141.101.105.40|141.101.105.40]] 19:39, 29 January 2021 (UTC)

I think the crow in the video is actually a hooded crow (Corvus cornix) rather than a jackdaw... [[Special:Contributions/108.162.245.146|108.162.245.146]] 20:39, 29 January 2021 (UTC)

Good catch. [[Special:Contributions/172.68.129.134|172.68.129.134]] 20:58, 29 January 2021 (UTC)

I think the crow in the video needs more training. Seems she's not really sure how the sledding works. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 01:04, 30 January 2021 (UTC)

Coincidentally, I just heard about a pet/tame duck (called 'Duck') who is bodysurfing with their human in Australia. No idea where crabs come into that. They've probably been eaten by the sharks, or poisoned by almost every other creature in and around Australia. [[Special:Contributions/162.158.111.185|162.158.111.185]] 04:34, 30 January 2021 (UTC)

2415: Allow Captcha

2021-01-23T08:19:41Z

162.158.111.185: /* Explanation */ spelling

{{comic
| number = 2415
| date = January 23, 2021
| title = Allow Captcha
| image = allow_captcha.png
| titletext = To prove you're human, please click all the number pairs that appear together in your Social Security number.
}}

==Explanation==
{{incomplete|Created by a malicious design practice that already exists out there. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

Captcha is designed to prevent spambots from being able to post on websites by posing challenges that humans can easily solve but that spambots and other automated programs cannot solve. The original version (used in [[632: Suspicion]]) asked users to identify text that was rotated, warped, or otherwise modified in order to make it more difficult for automated programs to solve. Once automated programs got good at that, new captchas were put out that exploited the fact that computers tend to be bad at image recognition, e.g. asking the user to select only images that contain cats from a grid of images of cats, dogs, and other objects. This captcha appears to combine the two methods—with the additional hurdle that in order to pass the captcha, users must be able to not only read but also understand (i.e. know the definitions of words). However, if the goal is to allow humans but not computers to pass (although, as the next paragraph will describe, it is not), this is not a good method of differentiating between the two. Some of the words, such as allot, appear to be fragments of other non-verb words (like ballot), and other words are non-verbs that could be confused with verbs. The English language has no distinction between nouns and verbs by spelling, only grammatical usage, and many words in English are both nouns and verbs. On the other hand, any computer program that can accurately read text (and there are now many programs that can do so) would not get confused between ale and ail or between skew and askew and would be able to look up the definitions (including parts of speech) online, so this would not be effective as a captcha.

In reality, however, the window is merely disguised as a captcha in order to trick human visitors into allowing the website to install "a helper tool", which may be malware, on their computer. The fact that the top uses a similar shade of blue to the current version of reCAPTCHA (currently the most common brand of captcha), the top includes the phrase "to prove you're human", and the grid is similar to the grid used by reCAPTCHA—albeit 4×4 instead of 3×3. However, positioned to appear to humans as two reCAPTCHA boxes is a window asking viewers whether they want to allow or deny the website's request to install "a helper tool", which may be malware, on their computer. The idea is that because allow is a verb beginning with the letter A, human visitors would click on what they think is the box with the word allow in it but actually allow the website to install potential malware on their computer. The window attempts to disguise this by formatting many of the words in boxes as buttons and including other text in smaller font on other boxes as well. In addition, the captcha may be intentionally difficult so that users will be too distracted by wondering whether ail or ale is a verb and the like.
It should be noted that simply tricking humans would not necessarily be enough to install malware on their computer. First of all, while a person can select any part of a grid box in order to select that box, only clicking on the actual button that says allow will allow malware unto the computer. If a person clicks on another part of the supposed box, nothing will happen, so the person will likely take a closer look in order to see why the window is not being selected and then possibly realize that this is a trick as a result. In addition, in order for the user to install software, a second window may pop up requiring the user to type in an administrator password, which will likely startle the user. Also, the user's computer may have an anti-virus software that will prevent the computer from executing malicious code downloaded by the website.

Shady websites often use similar tactics to trick you into allowing notifications, including saying "[https://www.bleepstatic.com/swr-guides/c/click-allow-to-verify-that-your-are-not-a-robot/notification-subscription-page.jpg Please allow notifications to confirm you are not a robot]". This comic combines that with a traditional recaptcha to try and trick savvier users too.

Title text is a similar recaptcha thing trying to also do identity fraud at coords 3,3 and 4,3.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

{{comic discussion}}

2414: Solar System Compression Artifacts

2021-01-21T10:55:26Z

162.158.111.185: /* Explanation */ Did some rough but diligent estimations, for myself, and then couldn't imagine the 1AU 'pixels' could be a coincidence.

{{comic
| number = 2414
| date = January 20, 2021
| title = Solar System Compression Artifacts
| image = solar_system_compression_artifacts.png
| titletext = Most of our universe consists of dark matter rendered completely undetectable by our spacetime codec's dynamic range issues.
}}

==Explanation==
{{incomplete|Created by a MISSING PHYSICAL PHENOMENON LOST DUE TO HIGH COMPRESSION. More on the title text - Dark matter and dynamic range issues need to be explained in more detail. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

{{w|Voyager 1}} is a [[:Category:Space probes|space probe]] launched by the United States in 1977. Originally designed to study the outer planets of the {{w|Solar System}}, it is now several decades into an extended mission beyond Neptune.

When images are compressed by a {{w|lossy compression}} format (e.g. {{w|JPEG}}), visual artifacts are created. The Voyager probe has made history for passing many milestones of our solar system. Randall here is suggesting that the probe has passed the artifacts. This cannot be true, as the solar system does not have compression artifacts{{Citation needed}}. However, the slightly discolored regions often created by compression may be a metaphor for the region of space that that solar radiation prevents from being a complete vacuum. Voyager 1 has passed through numerous such boundaries, as mentioned previously in [[1189: Voyager 1]].

Compression artifacts are often caused by large changes in coloration over a short distance, and Randall could feel that the drastic change in coloration from bright sun to dark vacuum could be creating a compression artifact around the Sun, somewhat like the Sun looking blurry due to low video quality. However, there is no definite region where solar radiation stops, only a boundary where it fades to a level lower than that of radiation from other sources. Some compression methods result in compression artifacts that behave in the same way, fading as the distance from the color boundary increases but never completely disappearing. (They may become literally unnoticeable because hexadecimal color values are discrete, but the compression artifacts will persist as slightly different RGB values before rounding to the nearest integer.)

The 'solar system' in the snapshot appears to be a 4-bit greyscale-plane at a more pixelated level than the image given. It can be picked out as being in 16 'banded' levels from the brightest (solar disc?) to darkest (extrasolar expanse?), with irregular or non-trivial transitional edges but no obvious or dominant dithering or noise. The Voyager image (and track) is overlaid at finer resolution in the white 'line drawing' format.

The 'apparent pixels' seem to be at a resolution of close to the order of 1AU². A rough count of the pixelation boundaries from the craft to the leftmost edge, plus an additional allowance for the likely radius of the 'sun' (or, rather, its solar wind density, or similarly represented measure) still beyond the edge, is surprisingly close to to the 150 AU or so of distance that Voyager 1 is at, currently. (For perspective, the Earth is then ''by definition'' 30ish of the lower-resolution 'pixels' beyond the left of the image just (or within) one 'pixel' from the spot inhabited by the Sun itself. - The overlaid Voyager 'sketch' then stretches out over maybe a dozen such low-res pixels/AU, which is equivalent to slightly more than the radius of Saturn's orbit or the entire diameter of Jupiter's!

In the title text the mystery of the undetectable {{w|Dark Matter}}, which is makes up most of the mass in the universe, is explained since this dark matter is rendered completely undetectable by our spacetime codec's {{w|dynamic range}} issues.

==Transcript==
:[Irregular bands of gray are shown, shading from a white circular segment on the bottom left side of the panel to completely black on the right. The bands have pixelated edges. A small white space probe is shown just outside the last dark gray band, in the completely black are. A dotted line starting from inside the dark gray ending at the space probe indicated that it is moving to the right out of the gray area. Close to the white area there are many bands packed closely together and with hard to define edges. But there are five gray areas clearly separated from the white, with a tendency to be elongated towards the space probes direction.]

:[Caption below the panel:]
:Milestone: '''''Voyager''''' has passed through the streaming video compression artifacts that mark the edge of the solar system

{{comic discussion}}

[[Category:Space probes]]