explain xkcd - User contributions [en]

3134: Wavefunction Collapse

2025-09-07T05:08:33Z

2607:F140:400:AF:748F:3D56:1EAF:BCC: /* Explanation */ Grammar fix

{{comic
| number = 3134
| date = August 27, 2025
| title = Wavefunction Collapse
| image = wavefunction_collapse_2x.png
| imagesize = 656x272px
| noexpand = true
| titletext = Wavefunction collapse is only one interpretation. Under some interpretations, graduate students also have souls.
}}

==Explanation==
{{incomplete|This page was created BY A SOUlFUl PARTICLE DETECTOR. Should the reference to unsolved problem be removed? Those comics are very different to this and the other two mentioned as it is three different things not three replies to one question. And cursed is not the same a wrong or chaotic!}}

This comic presents three possible responses to a common question posed by undergraduates upon confronting the {{w|Measurement problem|problem of measurement}} in quantum mechanics - does the apparently privileged role of subjective or conscious {{w|Observer (quantum physics)|observers}} in wavefunction collapse imply that human consciousness itself impacts physics? This question is sometimes phrased as: does the observation effect or quantum collapse prove humans have souls? These questions stem from a misunderstanding of what an "observer" in physics really is, a misunderstanding the comic depicts with a college student asking his professor about human consciousness.

The 'Bad' option shows Cueball telling his student that everybody has a soul, and their individual consciousness affects reality in some way. The 'good' option shows Cueball telling his student that consciousness doesn't play a role at all, and that it is 'just a physical measurement'. The 'chaotic' option shows Cueball apparently observing that the wave function collapses only when ''he'' looks at it, because he is special in some way (in this case, Cueball is a professor while Hairy is the undergraduate student).

That quantum states exist as probability density distributions, but are only ever observed in definite states, begs the question of how the quantum world transitions into the classical world. The (historically) most popular {{w|Copenhagen interpretation|interpretation}} posits that {{w|wave function collapse}} occurs upon the measurement of a quantum state, in which the multiple mathematically possible states resolve into a definite state, without explicitly defining precisely when this "collapse" occurs, or what defines "measurement;" in fact, when measuring, say, an electron in a superposition of two states, wavefunction collapse could occur at any stage from the electron interacting with the detector, to the detector recording the measurement, to the scientist observing the recording. A famous though experiment, {{w|Schrödinger's cat}}, takes this to the extreme: if a cat is placed a box with a decaying radioisotope that upon decay triggers a gas bomb that kills the cat, shouldn't this place the cat-bomb-isotope-box system into a mixed state that only undergoes wavefunction collapse upon opening and observing whether the cat is alive or dead? The Copenhagen interpretation is agnostic to this question, only confirming that the cat will have resolved into its alive or dead state at or before observation. The {{w|Consciousness causes collapse}} postulate endorsed by the "bad" panel -- unfashionable now, but taken seriously historically -- posits that the conscious observation is indeed what triggers wave-function collapse. The 'good' panel, rather flippantly, seems to endorse a more modern {{w|Quantum decoherence|decoherence}}-based interpretation - that every interaction inside the cat-box system is a "measurement" that destroys the superposition well before the human observer enters the picture. Finally, the `chaotic` option is far more radical and sollipsistic than the `bad` - it's not merely conscious observation that causes collapse, but PhD-holding and tenured consciousness.

Good, bad, and chaotic are likely references to the {{w|Alignment (Dungeons & Dragons)|alignment system}} in the role-playing game {{w|Dungeons & Dragons}}. In D&D, roles are characterized by their morality (good/neutral/evil) and their views about order (lawful/neutral/chaotic).

The title text continues the chaotic option. Graduate students are intermediate between undergraduate and professors. It is unclear whether graduate students can cause waveform collapse, and therefore have souls.

==Transcript==
:[Hairy is sitting behind a desk with one a hand on the desktop and the other in his lap. He is looking up at Cueball, who is standing in front of the desk. Hairy is asking a question:]
:Hairy: If the wavefunction only collapses when I observe it, does that mean my consciousness affects the universe?

:[Three panels follows showing three possible responses from Cueball. Each panel has a label above, written inside a small rectangle that is overlaid on the top left of each panel. Each panel shows the same zoom in on the top half of Cueball.]

:[Panel 1]
:Bad:
:Cueball: Yes. Quantum entanglement proves that we all have souls.

:[Panel 2]
:Good:
:Cueball: No. Consciousness plays no role here. Its just physical measurement.

:[Panel 3]
:Chaotic:
:Cueball: No. The wave function collapses when '''''I''''' look at it because I'm a full professor.
:Cueball: It won't collapse for an undergraduate.

{{comic discussion}}<noinclude>

[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Cueball]]
[[Category:Physics]]
[[Category:Religion]]

3131: Cesium

2025-09-07T05:02:46Z

2607:F140:400:AF:748F:3D56:1EAF:BCC: /* Attracting the attention of all of the above */ Corrected capitalization

{{comic
| number = 3131
| date = August 20, 2025
| title = Cesium
| image = cesium_2x.png
| imagesize = 588x298px
| noexpand = true
| titletext = Someday I hope to find a way to mess up a recipe so badly that it draws the attention of the International Air Transport Association, the International Mathematical Olympiad, or the NSA.
}}

==Explanation==

{{w|Cesium-137}}, or Cs-137, is a radioactive {{w|isotope}} of {{w|Caesium|cesium}} (officially spelled 'caesium', internationally). This comic was posted the day after the {{w|FDA}} posted an [https://www.fda.gov/food/alerts-advisories-safety-information/fda-advises-public-not-eat-sell-or-serve-certain-imported-frozen-shrimp-indonesian-firm advisory] about frozen shrimp sourced from an Indonesian firm because the shrimp were near materials contaminated with Cs-137 during shipment. A sample of breaded shrimp was [https://archive.ph/ri4tv confirmed to have been contaminated.]

Rather than being concerned about the potential health impacts, [[Megan]] and [[Cueball]] are curious about the technical details that led to this contamination. Cs-137 is normally a by-product of nuclear reactors and is occasionally used in {{w|Food_irradiation|food irradiation}}, along with other more common uses. Cueball and Megan cannot fathom how one could unintentionally contaminate shrimp with radioactive material, let alone with just one specific isotope. Cueball then comments that his biggest culinary screw-up attracted the attention of only his local fire department, likely because he set something on fire while cooking. A real-life example of seemingly-random contamination by Cs-137 was the {{w|Goiânia accident}} in Brazil.

The title text says that one of Cueball's (or possibly [[Randall]]'s) ambitions is to draw the attention of various organizations (the {{w|International Air Transport Association}} (IATA), {{w|International Mathematical Olympiad}} (IMO), or {{w|National Security Agency}} (NSA)) with a recipe he has butchered, either by accident or, more likely in his case, on purpose. Possessing and accidentally or intentionally releasing a radiation source like Cs-137 could get the attention of the NSA. Needless to say, it is difficult to imagine a cooking error that could be in any way brought to the attention of IATA or IMO.

A "[https://www.merriam-webster.com/dictionary/recipe recipe]" means a set of instructions for making something, typically from various ingredients. (Such as a prescription for a pharmacist, a chemical formula, or step by step instructions to perform a procedure.) Cooking recipes are a very common example of chemical processing instructions. To "mess up a recipe", in the sense of cooking it for oneself or a small group of others, would be unlikely to create a problem on a scale that an international agency would take note of. A recipe that was published for others to use could cause more significant problems if it led to harm to many people. This might involve ingredients that were poisonous, or preparation methods that were unsafe.
A particularly ill-considered thing is sometimes referred to as "a recipe for disaster". A number of these might be of interest to security agencies.

===How to attract attention===
====Attracting the attention of the IATA====
If the recipe is used in major airports and the recipe is contaminated with a drug, the pilots that consume it could experience vision loss or other problems, and if this recipe is widely used and normal people won't notice much besides minor side effects or negative effect was widespread enough where it affected very many flights, then this could attract the attention of the IATA in its primary role of a trade organisation. As a similar example, some airlines have mandated that the captain and first officer eat meals prepared in different kitchens in order to decrease the likelihood that they would both develop food poisoning severe enough to prevent either of them from being able to fly and land the plane. Not all airlines have these mandates, but a food poisoning incident like {{w|Zero Hour!}} would likely prompt IATA to institute this policy for all of its members, especially if it ended in a fatal crash. Variations of this concept could even fall under its guidances for how to transport hazardous goods.

Another possibility would be to cook a souffle so high and fluffy that it reaches airspace (like weather balloons sometimes do), or to sauté something that is very smokey, such as chili peppers, so that the smoke interferes with airspace (like the eruption of the volcano Eyjafjallajökull). Or rig up a pressure cooker to shoot pasta sauce out of its release valve. Or use the jet engine to pluck chickens. Rather than IATA, though, some of these may first and foremost be issues primarily investigated by the {{w|Federal Aviation Administration}}, instead, at least if occuring within the environs of the United States.

====Attracting the attention of the NSA====
There could be a secret code hidden in the ingredients of a recipe, and if the code affects the whole nation, this could attract the attention of the NSA. However, a much harder way is to have a similar incident with the shrimp, but at a much larger scale and possibly affecting a lot of different foods, if this threat is big enough, the NSA will investigate if there are people purposely doing this.

====Attracting the attention of the International Mathematical Olympiad====
A recipe to attract the attention of the IMO is much harder to imagine. Randall's best chance might be to cause an incident with some mathematically interesting property that inspires a math puzzle to be written about it. Another possibility is some person is trying to give answers to a person in the Olympiad by giving the person a recipe with the answers as a secret code inside, thus attracting the attention of the IMO. If mass food poisoning happens at math Olympiad it can also get some attention, though that would require working for IMO as caterer or at some restaurant near the location where Olympiad is held. However, these are most probably all on purpose or would be not allowed to be served for reasons unrelated to IMO and it would be very unusual to accidentally make these recipes. About a week prior to the publication of this comic, [https://www.independent.co.uk/life-style/math-question-viral-elementary-school-bobby-seagull-b2807395.html a botched "math exercise" about baking that lacked an actual question] went viral and was reported on by traditional media, but it happened at an elementary school, completely unrelated to the IMO.

Alternatively, Randall might find a way to develop a new form of geometry, topography, etc. which overturns long-held beliefs in mathematics. Accidentally doing something like that (say, proving [[2939: Complexity Analysis|P=NP]] or when like [[704: Principle of Explosion|Cueball derives his friend's mom's phone number]]) is common in XKCD.

====Attracting the attention of all of the above====
To attract the attention of IATA, NSA, and the IMO, it would be very difficult. You could make a meal that is fed to IMO participants, airline pilots, and has a secret national level code inside, that is slightly contaminated (to not raise suspicion beforehand). This would be very hard but possible and will attract the attention of all 3.

A pharmacy or chemical supplier messing up a chemical recipe and dispensing the wrong medication could affect people from the NSA, IATA and IMO, and thus attract attention from all three.

==Transcript==
:[Megan looks at a news story on her phone while talking with Cueball. Cueball is looking at Megan]
:Megan: There's a recall of frozen shrimp contaminated with cesium-137.
:Cueball: With ''what?''
:Megan: I know, right?
:Cueball: ''How!?''

:[Megan has put her phone away and she shrugs with her arms held out palm up, looking at Cueball.]
:Megan: No idea, but I bet it involved some expensive equipment. Those cesium sources aren't cheap.
:Cueball: Man.

:[Megan stands normally while Cueball holds a hand to his chin, looking down.]
:Megan: It's honestly a little inspiring to realize that it's always possible to screw up in a totally new way.
:Cueball: Yeah, the biggest agency whose attention '''''I've''''' drawn by messing up a recipe is the local fire department.

{{comic discussion}}<noinclude>

[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Food]]
[[Category:Physics]]
[[Category:Math]]
[[Category:Smartphones]]