2952: Routine Maintenance

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search
Routine Maintenance
The worst was the time they accidentally held the can upside down and froze all the Earth's magma chambers solid.
Title text: The worst was the time they accidentally held the can upside down and froze all the Earth's magma chambers solid.

Explanation[edit]

Ambox notice.png This explanation may be incomplete or incorrect: Created by an ONCOMING LETHAL DUST CLOUD - Please change this comment when editing this page. Do NOT delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

This comic is almost certainly a reference to chapter 9 of the book The Little Prince by Antoine de Saint-Exupéry. On the first page the following quote can be found: "On the morning of his departure he put his planet in perfect order. He carefully cleaned out his active volcanoes."

A recommended routine maintenance step for many electronics, such as desktop computer towers, is to remove the buildup of dust on a regular basis. This can help prevent the electrical components from overheating, and lengthen their lifetime. To make this job easier, safer, and cleaner, there exist cans of high-pressure gas, as depicted, which force through high-flow gas to displace the dust. (Attempting to do this with air from the lungs would be less effective, may add unintended moisture to the electronics, and could result in a face-full of dust.[citation needed])

The comic suggests that a similar maintenance step is performed on the Earth itself, blowing gas into the Earth to force out the dust from its magma chambers. However, filling the atmosphere with dust would be unhealthy and fatal to living beings, so as a safety measure everyone would have to take shelter.

This may be a reference to one theory about the K-T extinction event — that a crashing meteor sent so much dust into the air that it killed off many plants and animals, including all non-avian dinosaurs, in a much wider area than that directly affected by the initial impact. Those lineages that chanced to survive the global effects must have been able to escape the worst of the disrupted ecosphere while the worst of the atmospheric effects subsided, and were then able to exploit various newly vacant (and/or changed) environmental niches. (This would include our own mammalian ancestors, and the avian dinosaurs that led to todays birds; some of them may, perhaps, have survived by already being more inclined/suited to living in burrows.) However, this dust cloud would have lasted longer than the 48 hours suggested in the comic.

The image suggests that the "routine maintenance" for Earth would involve using the Hawaii hotspot (possibly via its most active volcano, Kilauea), as the point to insert the high-pressure gas, causing volcanoes to erupt in Iceland, the Aleutian Islands or the Kamchatka Peninsula, the Andes, and elsewhere; the two geographically-indeterminate plumes may represent Italy and Indonesia.

The title text mentions using the can upside-down, and this freezing solid the magma chambers. Pressurized canisters of "air", as with similar aerosol sprayers, contain a propellant gas that condenses into a liquid when compressed. When the spray valve is opened, the release of pressure allows some of the liquid to evaporate and take the place of the released gases, or become some of the gas subsequently released (or all of it, if its purpose is not to spray other contents). The transition of the propellant liquid/gas from dense liquid to space-filling gas requires it to 'boil off', this process needing to pick up heat (or 'enthalpy') energy. Under typical operation, the cooling liquid/gas takes heat from the general mass of the can itself as it tries to attain thermal equilibrium. As a result, the can (and the expelled gases) will be cooled a little. Then (ultimately) heat will also be taken from anything touching or surrounding the slightly cooled can and its spray. This is precisely how a purposeful refrigerant acts, either as a one-time process or as a reversible cycle where re-pressurizing a suitable gas can 'release' heat (the heat/enthalpy of condensation) at the 'hot side' of a refrigerator, returning the gas in the system to liquid that it can later let boil again and cool the 'cold side' of the refrigerator.

It is not normally useful for such a can to allow the liquid propellant-in-waiting to exit the container, as it would waste its usefulness as a source of pressure once it does. But by holding the container the wrong way up (which way that is being dependent upon its design, and intended use...) the pressurized contents push the liquid out via the nozzle's stream. The now exposed propellant is now free to evaporate into the air at atmospheric pressure, typically much lower than the constraints it had within the can, after landing directly upon whatever the can was sprayed at. The resulting demand for heat energy (much more rapid than normal, and likely concentrated upon a much smaller target than the can itself represents) produces a greater localized drop in temperature and can lead to freezing nearby liquids (which may or may not be intended/useful). Of course, the total 'cooling effect' of such a can does not change, depending upon how it is (mis)used, it merely changes the extent (and lifetime) of application, and how extreme the temperature change may be within a much more limited 'liberation' of its cooling ability.

Spraying "canned air" with the can inverted is a party trick used to very quickly cool beverages, being able to bring them down from room temperature to ice cold in seconds if performed correctly.

Some spray cans are designed to freeze objects, e.g. to help in plumbing repairs or finding overheating electronic components. Freeze spray is also used in medical applications. These require careful use to avoid unintentionally (or intentionally!) damaging exposed skin or objects that can be damaged by local temperature differences, such as glass.

Given the location of the planetary-scale dust-busting 'air canister', it may be considered confusing which 'way up' is the correct orientation, given that Earth-gravity would be pulling the contents sideways (however that changes what the nozzle ends up ejecting from the can itself). But such a large can would also have its own significant internal 'can-centric' gravity that possibly (depending upon how full of still-liquid propellant it is) exceeds that of the Moon, possibly letting all the denser liquid hold itself into the centre of the canister, even against the nearby Earth's gravity. Being significantly closer to the Earth than the Moon is, this can could also be a far greater influence upon Earth's own tides (not alluded to in the comic), making the dusting of the atmosphere or the freezing of some of its magma secondary issues to the sheltering population. But if magma froze to the extent of disrupting or disabling the Earth's magnetic field, this "secondary" issue could quickly become primary, even existential.

Three comics after this one Randall released 2955: Pole Vault, where the Earth is being punctured by the tip of a pole vaulting stick causing the Earth to burst like a ballon. That idea seems to be similar, but opposite the one from this comic. With so few days between the releases there might have been some similar thoughts behind the creation of both.

Transcript[edit]

[The nozzle of a gas duster can is pointing into a hole on the Earth's surface in the Pacific Ocean around where Hawaii is located. This point is on the left side of the depicted Earth, so north America is centered on the drawing, with the top of South America visible beneath it. Greenland and Iceland and the most eastern part of Russia is the only other land visible. The trigger on the can is pressed as an arrow indicates and lines around the nozzle indicates that air is pushed out of the can. This results in dust clouds being released from at least five spots of the Earth, three of these are on the visible side of Earth and the volcanoes that erupts are visible, one only the top of the volcano can be seen and the last only the cloud can be seen. Other volcanoes could be erupting on the other side of the Earth without there being any visible clouds from this vantage point. The visible eruptions are in the Aleutian Islands or Kamchatka Peninsula, on Iceland and in the Andes. The one where the volcano can be seen is in Asia, most likely Japan, and the other where only the cloud can be seen is most likely in Europe, perhaps near the Mediterranean ocean. The can has a label with several lines of text, most of it unreadable. But there is a large label on it and a readable text below this:]
Dust-Off
Compressed air
[Caption below the panel:]
I know routine maintenance is important, but I hate how we all have to take shelter for 48 hours every year while they flush out the Earth's magma system for cleaning.


comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!

Discussion

Ooooh, if this were only true... All the "Nobody tells me what to do" stubborn people would have died out years ago, and Covid would have been a LOT shorter! :) Added an initial explanation, all I found here was a basic transcript.

The vent off of Alaska is poking out, is there a volcano around there? Feels a little north to be Mount Fuji, but I have a suspicion most if not all are supposed to be actually volcanos... NiceGuy1 (talk) 04:12, 29 June 2024 (UTC)

Russia's Kamchatka Peninsula (the long "teardrop" hanging below the Siberian Peninsula) is very volcanically active. The others look like reasonable places to expect volcanoes - I've added a couple of lines. 172.68.64.207 05:25, 29 June 2024 (UTC)

Is the image SUPPOSED to be that tiny? It's not even 800 pixels! 141.101.109.166 05:46, 29 June 2024 (UTC)

Should the direction of up/down actually being away/towards the planet due to gravity and not the panel's up/down direction be addressed in the explanation? 172.71.31.150 13:34, 29 June 2024 (UTC)

The current explanation says that cans of compressed air are pressurized with a propellant gas. This seems unlikely to me, but it's not impossible... it's just that I'd expect a can of compressed air to be only that, without needing a propellant. What I'm seeing in a quick search on-line supports that. Do cans of air/propellant exist? BunsenH (talk) 16:09, 1 July 2024 (UTC)

It would be impractical to have just normal air, compressed. A typical spray can cannot hold the pressures needed to have significant (i.e. useful) amounts of compressed 'normal air' (still gas, but a lot of it... think, basically, of a cylinder of Nitrogen gas, because air is mostly that anyway). And 'typical air' doesn't readily liquify (the way of concentrating it without necessarily extreme pressure), not without applying/maintaining extremely low temperatures.
On the whole, regular mostly nitrogen plus significant oxygen plus some CO2 and a host of trace gases would never practically fit in a handy spray can such as you could hold (and, probably, afford to use) as an alternative to any pumped compressed (or fan-blown) air in 'trivial' tasks such as just blowing a tiny bit of dust off of a mobo.
What the 'air' is, in such cans, is probably (mostly) whatever handy liquid-adjacent gas is usable as an actual propellant. As you only need the 'general gas', you might as well just put propellant in the thing (one that works well) and nothing else. (Unlike things like air-fresheners/bug-spray, which need the 'freshener'/insecticide as well. There's no advantage to reducing the propellant to fit 'air' in, which would soon be so diluted by gasified propellant that you'd basically have no 'air' left).
The listed possible gases in a gas duster are the likes of butane, propane, 1,1-difluoroethane, 1,1,1-trifluoroethane or 1,1,1,2-tetrafluoroethane, with the first two being flammable (so would be problematic in some circumstances) and the rest being more inert but still not being 'safe' if improperly used. Or abused.
I don't actually have a can, at hand, or I'd check its stated ingredients (and warnings). I probably am more likely to (carefully) blow dust away with my own breath, or get the vacuum cleaner out with a suitable attachment. In fact, I've used very few, ever, though I probably first did back in the early '80s (which means it might even have been basically an example (or mix) of a CFC gas, before the problems with that became 'a thing'), as part of a cleaning kit sold to service my BBC Micro. 172.70.86.35 17:44, 1 July 2024 (UTC)
The popular 'can dusters' are NOT compressed air (oxygen/nitrogen mix) despite the label -- air cannot stay liquid at room temperature, it is high above the critical points of both nitrogen and oxygen. Many of such dusters don't display ingredients, but have a prominent FLAMMABLE warning sign! It is a propane/butane mix most of the time, maybe some CFCs in old ones. You could make a flame torch out of them! so be careful, turn off your device and provide very good ventilation. Best use it outdoors or on a patio, etc. -- 172.68.159.20 18:04, 1 July 2024 (UTC)
I was looking at this product, which claims to be VOC-free. But when I dug into its SDS, I saw that it's based on 1,1-difluoroethane. "Non-flammable product. However, content in liquid form is flammable." BunsenH (talk) 22:38, 1 July 2024 (UTC)

The image looks SO much like a first-draft storyboard for 'Spaceballs'. These Are Not The Comments You Are Looking For (talk) 02:15, 2 July 2024 (UTC)

Given that a second one is apparently in the making... Maybe Randall knows more than we would guess. Elektrizikekswerk (talk) 06:53, 2 July 2024 (UTC)

I'm thinking that the 'tidal' effect of the can is probably going to start tearing both earth and can apart, so it's unlikely to become secondary to losing magnetic field.172.70.90.176 08:57, 2 July 2024 (UTC)

Why isn't the Yellowstone Hotspot on the map? -- Cwallenpoole (talk) 19:31, 2 July 2024 (please sign your comments with ~~~~)

Are there any actual magma vents, currently, in Yellowstone? From what I recallz and without checking, there are geysers (which are seeps of water driven up by the thermal conduction from the hot rock) but no 'eruption' points that might readily release dust-busting gas as well. (That might, in fact, be the problem. If magma pressure builds up there, it'll take a while to fracture the surface and vent, erupting massively, as opposed to a relatively slight eruption in a currently active/semi-active volcanic zone like Iceland/etc, being locally disruptive but not so bad if not confounded by glacier-topping or whatavyer...) 172.70.162.185 20:46, 2 July 2024 (UTC)


I added an explanation that this is almost certainly a reference to the book The Little Prince, in chapter 9 there is a detailed explanation of how important it is to clean out volcanoes. satur9nine 19:33:25, 02 Jul 2024 (UTC)

I have just made this Category:The Little Prince and added this and five other comics to it. --Kynde (talk) 10:50, 7 July 2024 (UTC)