Editing 2952: Routine Maintenance

{{comic
| number    = 2952
| date      = June 28, 2024
| title     = Routine Maintenance
| image     = routine_maintenance_2x.png
| imagesize = 299x413px
| noexpand  = true
| titletext = The worst was the time they accidentally held the can upside down and froze all the Earth's magma chambers solid.
}}

==Explanation==
{{incomplete|Created by an ONCOMING LETHAL DUST CLOUD - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic is almost certainly a reference to chapter 9 of the book {{W|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 {{w|Gas duster|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 {{w|Hawaii hotspot}} (possibly <em>via</em> its most active volcano, {{w|Kilauea}}), as the point to insert the high-pressure gas, causing volcanoes to erupt in Iceland, the {{w|Aleutian Islands}} or the {{w|Kamchatka Peninsula}}, the {{w|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 {{w|Enthalpy of vaporization|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.

{{w|Freeze spray|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 {{w|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==
:[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:]
:<big>Dust-Off</big>
: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.

{{comic discussion}}

[[Category:Geology]]
[[Category:Volcanoes]]
[[Category:The Little Prince]]