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Asteroid Mission
Lander, this is Houston. There's been a request that you turn clipping back on and instead set the mass to 1kg. The theorists believe that will be pretty funny.
Title text: Lander, this is Houston. There's been a request that you turn clipping back on and instead set the mass to 1kg. The theorists believe that will be pretty funny.

    Explanation

    The comic shows the scenario of an asteroid on a collision course with the Earth, and the crewed space mission sent to prevent this, as as in the films Armageddon, Deep Impact and various other stories not dating from 1998. Typically, such fictional missions are sent to blow the offending objects up (or else the more realistic and practical option of ensuring that they are nudged away from the Earth-hitting course), but here they are apparently attempting to gain access to the asteroid electronically and implement a "noclip" command.

    This refers to noclip mode in video games: "A cheat that allows players to pass through normally impenetrable objects – walls, ceilings, and floors – by disabling clipping." In most multiplayer games this would be considered cheating and result in a ban. In others it may disable achievements, or requires explicitly and visibly enabling cheats. Often it functions from a built-in developer console, such as in Source games such as Half-life or Portal, where it was originally made available to shortcut some aspects of gameplay testing that was left in either as an Easter Egg or just by being forgotten. In other cases, though, it requires a third-party hacked client, such as in Geometry Dash, where the noclip mod in many clients allows the player to pass through obstacles without dying. By enabling noclip on an asteroid headed for Earth, the asteroid will no longer interact with Earth, thus saving it. The only issue, however, is that the astronauts can't get to the ship if they can't push against the asteroid! This error would be trivial if they were tethered to the ship or possess personal propulsion units to use once they are no longer able to stand on the asteroid, but the mission does not seem to have enough foresight to include either of these things.

    The title text suggests that rather than enabling noclip, the astronauts instead just reduce the asteroid's mass to 1 kg. If the asteroid is assumed to have a volume of about 1000 km3, this would reduce the density of the asteroid to 10-15 g/cm3 and the energy of the asteroid to a few kJ. This relatively small amount of energy would be rapidly dissipated by friction with the outer atmosphere, and then the asteroid would float in the upper atmosphere, probably until the solar wind blew it away. During this event, the asteroid would rapidly approach the Earth, looming large in the sky, presumably terrifying much of the world's population. This would be "pretty funny".

    Transcript

    [A news reporter is standing in front of an image of a rocket.]
    Reporter: The asteroid is headed for Earth, but a mission has been launched to intercept it.
    [Cueball and Megan are walking off a lander with some equipment.]
    [A laptop is on the ground, and Megan plugs a peripheral from the laptop to the asteroid.]
    [Cueball types into the laptop.]
    Console: >noclip on

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    This Week's Explanation for Improvement

    As part of the Explanation Improvement Project, each week the community selects one older, neglected, or otherwise stagnant explanation to expand and polish together. This week's pick is 380: Emoticon; please help us improve it! To get involved with the project, you can also nominate an explanation or vote on current nominations!

    Emoticon
    U+FDD0 is actually Unicode for the eye of the basilisk, though for safety reasons no font actually renders it.
    Title text: U+FDD0 is actually Unicode for the eye of the basilisk, though for safety reasons no font actually renders it.

      Explanation

      Welcome to This Week's Explanation for Improvement! Anyone is encouraged to help explain comic 380: Emoticon; click here to get started! If you are new to wiki editing, you can read our editing FAQ for guidance. Here are some suggestions for improving this explanation:

        Explain that Cueball is not called Rob in this comic because the username is a reference; consider moving this to a more prominent position rather than the last paragraph?
        Link similar comics that feature chat clients.
        Give an historical background about old chatrooms and requests for A/S/L, which are now uncommon.

      A basilisk, originating in Greco-Roman antiquity, is a legendary creature reputed to have the power to kill, or turn to stone, any living creature with a single glance (a useful idea for metaphor, as in Shakespeare's Richard III, in which a widow wishes her eyes, praised for their beauty by her husband's killer, were basilisks and could "strike [him] dead"). In this comic Cueball doesn't appear to be turned to stone, he simply appears to have died.

      Cueball, who goes by "NICKM", chats online with a user named "BSLSK05" via instant messaging. He quickly learns, much to his dismay, that he is chatting with an actual basilisk, who kills him by texting him a smiley emoticon (a colon and a closing parenthesis: :)), humorously suggesting that the basilisk's power can extend beyond actual physical eye contact and is effective even with a mere visual representation of a pair of "basilisk" eyes as keyboard characters.

      The username "BSLSK05" is, of course, the word "basilisk" without vowels and with appended numbers. The numbers are probably an arbitrary string of digits users add to their usernames when their initial choice has already been taken, since most systems disallow the same username for different users.

      Cueball's question, "A/S/L?", is an online texting shorthand for requesting information about someone, specifically their age, sex, and location. This was commonly used when first meeting someone online in text-only mediums, especially in determining how they might wish to continue to converse with their correspondent - whether it might lead to online flirting or finding some other interesting topic of conversation. However, in some contexts, the question was considered creepy, inappropriate or disruptive. For people who were only interested in talking with existing friends or talking about a specific topic, dealing with unsolicited private messages asking "A/S/L?" was generally an annoyance. Such people may have wished for a way to make the questioner go away, though most would not have resorted to petrification to do so.

      The term has fallen out of style since the comic, with the introduction of avatars, profile pictures, and other methods of presenting a user's identity up front. Modern dating sites such as Tinder have built-in algorithms that automatically connect people whose preferences match, skipping the basic introduction stage of a first-time interaction entirely.

      The type of chat system pictured may be Internet Relay Chat (IRC), the earliest popular system used for instant messaging, as most IRC clients share the use of formatting usernames with surrounding angle brackets and prefixing event messages with "-!-".

      The title text refers to the Unicode character at code point U+FDD0, which is a non-character — this specific one is permanently reserved for internal application processing rather than regular text, meaning no font sets support the character. If you attempt to render the non-character in a text field or editor, it would either not show up or would display as an empty rectangle (🯄) or an invalid/missing character box (�). Unicode does, however, have many characters for representing images and icons/symbols, such as ✉ (Envelope), ☎ (Telephone), ✏ (Pencil), ✂ (Scissors), ⚙ (Gear), ★ (Star), ancient Egyptian glyphs, and (most popularly) emojis. The title text claims that U+FDD0 is actually the character for the eye of a basilisk (which does not exist), but is not rendered by any fonts for safety reasons, because it may kill anybody who looks at the character.

      The myth of the basilisk has been adapted into many places in popular culture which the comic may be referencing, rather than the original myth directly. In this comic, Cueball is explicitly not referred to as Rob, if his username is to be taken at face value. This is because, in Harry Potter and the Chamber of Secrets of the novel and movie series Harry Potter, a basilisk is let loose in Hogwarts School of Wizardry. The character going by "NICKM" could refer to the character Nicholas de Mimsy-Porpington, also known as Nearly Headless Nick, a ghost who, in the story, becomes a victim of the basilisk's gaze. However, since he is a ghost and has already died, he is instead rendered immobile, or in the book, "petrified". Another possible reference is the Basilisk monster from the Dungeons & Dragons Monster Manual. Here, the Basilisk is a monster with the special ability "Petrifying Gaze".

      Transcript

      [Cueball sits at computer, typing. The computer screen reads as follows:]
      -!- Opening Chat with BSLSK05
      <NICKM> Hi!
      <NICKM> A/S/L?
      [The next panel is unframed, with two smaller frames within it.]
      <BSLSK05> :)
      [Cueball looks stunned, flies backward.]
      [The two smaller frames focus in on BSLSK05's emoticon, implying rotation to show a smile and two open eyes.]
      [Cueball at computer slouches in chair, dead, crossbones above his head.]
      [At the remote computer, a basilisk is looking at its screen, pleased with its endeavours.]

      Trivia

      The unicode character used as the eye of the basilisk, U+FDD0 did in fact kill at least one chat client, Konversation (and presumably any other Qt-based chat clients using QTextDocument). This was because U+FDD0 is one of the 32 non-characters located in the block “Arabic Presentation Forms-A” used "to make additional codes available to programmers to use for internal processing purposes". According to the Unicode FAQ they are reserved for internal (private) use.

      However, QT's UTF-8 encoder let it through anyway. But QT's qtextdocument uses U+FDD0 as text frame delimiter so when it is appended to a QTextDocument, counters run wrong and eventually it crashes.

      D-bus closes the connection and crashes the client when it encounters illegal UTF-8, and KDE's notification system works through d-bus.

      The problem was fixed after the xkcd "report" and Konversation now handles unicode normally.


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