explain xkcd - User contributions [en]

2982: Water Filtration

2024-09-16T10:28:55Z

172.70.91.99: /* Explanation */

{{comic
| number = 2982
| date = September 6, 2024
| title = Water Filtration
| image = water_filtration_2x.png
| imagesize = 593x467px
| noexpand = true
| titletext = You'd think the most expensive part would be the quark-gluon plasma chamber, but it's actually usually the tube to the top of the atmosphere to carry the cosmic rays down.
}}

==Explanation==
{{incomplete|Created by WATER. JUST PLAIN WATER. NOTHING DONE TO IT, JUST PLAIN WATER. POSSIBLY DRINKABLE. PLAIN H₂O - Do NOT <s>DRINK THE WATER</s> delete this tag too soon.}}
This comic seems to be a diagram of how well water is purified, a common set of procedures done to make said water safe to drink. However, this well water is "purified" through a series of increasingly unnecessary, expensive, and possibly hazardous steps, ending with producing "pure" water synthesized from hydrogen and oxygen (which have each been synthesized from subatomic particles) - before promptly undoing all of the work by re-adding raw well water and its original minerals and probiotics, (which is one way of describing chemical and biological contaminants) "for taste and to support immune health". In real life, groundwater generally only needs treatment for any contaminants (chemical or biological) known to be a problem based on the results of water testing or an incident, but adding the original water back in could be dangerous if the water has not been sampled recently.
A faucet is "a device that controls the flow of liquid, especially water, from a pipe", commonly known as a ''tap'' in many parts of the world.

{| class="wikitable"
|-
!Step
!Real Device?
!Used for water treatment?
!Explanation
|-
|Water softener
|{{Yes|Real}}
|{{Yes}}
|{{w|Water softening}} is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted bonding with calcium ions. Soft water also extends the lifetime of plumbing and appliances by reducing or eliminating scale build-up in pipes, fittings, reservoirs, and so on. The comic shows the water either being passed through some granulated material (presumably, {{w|ion-exchange resins}}) or into a precipitation chamber for lime (or soda ash) softening. This is one of the few steps in this process that arguably fits the comic title of "Water Filtration."
|-
|Reverse osmosis
|{{Yes|Real}}
|{{Yes}}
|{{w|Reverse osmosis}} is a common step used in modern water-purification systems. It relies on using osmotic membranes and high pressures to separate water molecules from dissolved solutes and biological substances. Interestingly, it would also act as a softening step, rendering the previous step potentially redundant, depending on the goals for each step. It's also overkill for most wells, as groundwater often needs treatment targeted to only a few contaminants, if any treatment at all. This is one of the few steps in this process that definitely fits the comic title of "Water Filtration."
|-
|Ultraviolet Sterilization
|{{Yes|Real}}
|{{Yes}}
|{{w|Ultraviolet germicidal irradiation|Ultraviolet sterilization}} uses UV lamps at short wavelengths to damage the DNA and thereby kill micro-organisms in the water. In the USA, this is an uncommon method of well water sterilization, as the pathogens most likely to be found in well water (as opposed to surface water) are generally much more responsive to chemical disinfection. Many wells don't even need a disinfection step; whether this well needs disinfection or not, this is hardly the most impractical step in this treatment train.
|-
|Autoclave
|{{Yes|Real}}
|{{Yes}}
|{{w|Autoclaves}} are essentially large pressure cookers that sterilize items and liquids through exposing them to a high temperature (~120°C or ~248°F) over tens of minutes in presence of water. By maintaining a high pressure, the boiling point of water goes up. This creates a very hot and humid atmosphere, making efficient heat transfer with all contents and inactivating all biological entities through this heat. They are commonly used in hospital and laboratory settings to sterilize plastics, glassware, equipment and solutions (like bottles of growth medium for bacteria) to be used in a sterile environment. The advantage of this method compared to dry heat (aka putting things in a 150°C-180°C oven until they are sterile) is that most lab plastics survive a passage at 120°C without melting. While difficult to streamline (as this technique is used for batches), it has the advantage over light-based methods that heat gets everywhere, and that instead of just damaging DNA, you also denature the proteins and other structures of microorganisms.
|-
|Condenser
|{{Yes|Real}}
|{{Yes}}
|This step condenses the steam generated by the autoclave back into water. This is a normal part of the process used in "traditional" water purification by distillation.
|-
|Regular osmosis
|{{Yes|Real}}
|{{No}}
|Regular osmosis (also known as "osmosis") is the tendency of a solvent (like water) to flow through a semipermeable membrane towards the side that has a higher concentration of dissolved molecules or ions. It therefore goes from a purer state to a less pure state, the opposite of filtration.
|-
|X-Ray Sterilization
|{{Yes|Real}}
|{{No}}
|{{w|Sterilization_(microbiology)#Ionizing_radiation_sterilization|X-ray sterilization}} is used to sterilize equipment, and may also be used as a cold method (in contrast to techniques like pasteurization) of eliminating germs and killing insects in fresh foodstuffs. Has also been used to sterilize postal mail.
|-
|Carbon Filter
|{{No|Fake}}
|{{No}}
|The water is passed through some volume of carbon - a riff on activated carbon filters, which ''are'' used in water filtration as seen later in the process. The exact {{w|allotropy|allotrope}} of carbon is not mentioned, so this could possibly be a graphite, carbon nanotubes, or even solid diamond "filter". This is one of the few steps in this process that definitely fits the comic title of "Water Filtration."
|-
|Neutron Source
|{{Yes|Real}}
|{{No}}
|A {{w|neutron source}} generates high-energy neutrons. High-energy neutrons are highly penetrating and will cause ionization events to occur due to collision with atoms in the water. This can potentially make the water more radioactive due to the generation of radioactive isotopes.
|-
|Activated Carbon Filter
|{{Yes|Real}}
|{{Yes}}
|{{w|Activated carbon}} is a form of carbon commonly used to filter contaminants from water and air, as it has a large surface area available to adsorb impurities on its surface. While this isn't a strange step to see in a water purification process, Randall makes a pun here with its proximity to the neutron source - the carbon has been '{{w|Neutron activation|activated}}' by the neutron source, and is currently radioactive. Water filtered through this may pick up radioactive isotopes from the filter. This is one of the few steps in this process that definitely fits the comic title of "Water Filtration."
|-
|Gamma Ray Sterilization
|{{Yes|Real}}
|{{No}}
|Similar to x-ray sterilization, this step uses {{w|Sterilization (microbiology)#Ionizing radiation sterilization|gamma rays}} to sterilize the water. Gamma rays can potentially irradiate the water through photodisintegration if their energy is higher than the binding energy of oxygen.
|-
|Cosmic Ray Sterilization
|{{No|Fake}}
|{{No}}
|Similar to the previous step, but this time using high energy {{w|cosmic rays}} to do so. This would be incredibly impractical, as cosmic rays are generally blocked by the atmosphere at high altitudes (as stated in the title text). Furthermore, their extremely high energy (shown to be in the exa-electron volt (EeV, or 1018 eV) range) would cause multiple high-energy particles to be created on impact with the water molecules, irradiating the water significantly.
|-
|Electrolysis
|{{Yes|Real}}
|{{No}}
|The water is broken down into hydrogen and oxygen gas using an electric current. Assuming the gas outputs of this process are pure hydrogen and oxygen gas, this *would* be an extremely effective sterilization tactic, seeing as no known organism or water pollutant is entirely composed out of hydrogen or oxygen gas. Along with the next step, this step may be a misguided attempt to "take the water apart and clean each part individually". The hydrogen is sent to the ionizer, while the oxygen is sent to the oxygen spallation step.
|-
|Oxygen Spallation
|{{No|Fake}}
|{{No}}
|Almost all oxygen in existence was originally created via {{w|stellar nucleosynthesis}}. Now, in this step in the purification, the oxygen is apparently broken down back into hydrogen via a fictional form of {{w|Cosmic_ray_spallation|spallation}}. While spallation can form lighter nuclei from heavier ones, there is no known process to convert oxygen back down to hydrogen. It is unclear what happens to the neutrons present in the oxygen nuclei - whether they are removed, used to create hydrogen isotopes or allowed to decay into protons and electrons (the components of yet more hydrogen, when properly reintroduced). The hydrogen formed here is merged with the rest of the hydrogen before being sent to the ionizer.
|-
|Ionizer
|{{Yes|Real}}
|{{No}}
|The hydrogen output by the previous step is made into a plasma with free electrons and protons (not bound into atoms).
|-
|Quark-Gluon Plasma Chamber
|{{No|Fake}}
|{{No}}
|The plasma output from the previous step is further energized into a {{w|quark–gluon plasma}}, such as the one found just after the Big Bang. This follows the theme of the previous steps, which all serve to break the water down into their elementary components. The incredible energies involved in doing so are unachievable by current technologies (current particle accelerators can form such a plasma for very short periods of time and involve a very small amount of matter), and serve to highlight the impracticality of this setup (as alluded to in the title text). The energies would also result in formation of lepton pairs from energy, which is presumably where the electrons from the previous step ended up.
|-
|Hydrogenation
|style="background:#FFFF9E;vertical-align:middle;text-align:{{{align|center}}};{{{style|}}}" class="table-yes"|Kinda
|{{No}}
|This process converts the quark-gluon plasma output in the previous step into elemental hydrogen, reversing the previous two steps. Presumably, this is done via {{w|hadronization}} and {{w|recombination}}; however, it is unclear how the {{w|baryon asymmetry}} needed to generate matter and not anti-matter is developed. The resulting hydrogen is split into 2 streams leading into the Nucleosynthesis and Reverse Electrolysis steps. In real life, {{w|hydrogenation}} is the process of adding hydrogen to unsaturated hydrocarbons.
|-
|Nucleosynthesis
|{{No|Fake}}
|{{No}}
|Part of the hydrogen produced in the previous step is converted into oxygen via 2 sub-processes. The hydrogen is first converted into helium and carbon through a combination of the {{w|proton-proton chain}} and the {{w|CNO cycle}} as per the labels on the step. The helium and carbon are then converted into oxygen through the {{w|alpha process}}. This step may also involve the {{w|triple-alpha process}}, seeing that the alpha process is typically only applicable to converting carbon into heavier elements owing to the lack of a stable element with eight nucleons. These steps normally occur in the cores of massive stars. It is not known how the oxygen is filtered from the extremely hot plasma of fusion products.
|-
|Reverse Electrolysis
|{{Yes|Real}}
|{{No}}
|This step is essentially a fuel cell, utilizing an electrochemical reaction to convert hydrogen and oxygen back into water and electricity.
|-
|Adding Well Water
|{{Yes|Real}}
|{{Yes}}
|A second pipe is linked to the first that simply feeds untreated well water into the pipes, partially undoing the entire process. Even if the well water is only a small portion of the faucet water, its presence has now made the now incredibly pure water impure. This act of putting well water into the faucet after treating it may be a riff on the cultural interest in "spring water" or "pure glacial water" that is said to have additional minerals or beneficial properties but is oftentimes not meaningfully distinct from properly treated tap water. "Local minerals and probiotics added" may be a reference to Coke's "Dasani" brand drinking water, which is purified by reverse osmosis, and then has a package of minerals added to create the flavor (pure water's actual lack of flavor can be perceived as an unpleasantly 'flat' flavor).

In addition, drinking only {{w|Tonicity|extremely hypotonic}} liquid intake can induce the body to expel more water than it took in (taking with it some essential minerals that are not being replaced) to try to maintain equilibrium of concentrations. This effect is not directly dangerous, but could exacerbate other bodily deficiencies in the long term and have the issues of greater than necessary liquid throughput than with 'normal' drinking water. The tendency for {{w|Sports drink#Categories|many 'sports' or 'health' drinks}} to hype the term 'isotonic' is based upon the idea that an ideal concentration of solutes can be added, in-between the opposing problems of having either too many ''or'' too few 'impurities'. The process does not include adding untreated (and probably also untested/unquantified) ground water, which could carry pathogenic organisms and chemicals, and appears to have no mechanism for ensuring what ''might'' be an acceptable level of re-blending for the circumstances.

Alternatively, it may be that the level of purity achieved by this setup is so overkill, and the cost per liter processed so high, that it's simply more efficient to treat just enough of the water to dilute the rest of the water to acceptable levels of contaminants. For example, it's common to use a partial bypass to supply water to the shower, since shower water does not need to be potable. Also, some well water systems are clean enough to not need any treatment at all and can be used straight from the well, and some water systems are only slightly high in a single chemical contaminant that can be addressed by blending the water, either with treated water or another source (treated or untreated). Perhaps the treatment process led to enough radioactivity that blending with the original source was required to address radiological contamination (either gross alpha radiation or specific radionuclides).
|}

The title text briefly covers the cost implications of the components. Various 'real' filter elements will have material or energy costs or both, in operation or to replenish their effectiveness, and the high energy input needed to disassociate hadrons into raw quark–gluon plasma (at bulk levels) would seem to require the most in terms of running the equipment. But it is pointed out that to ''ensure'' enough cosmic rays reach that particular phase of sterilization, there would have to be a pipe (not shown) leading out to the edge of the atmosphere to optimistically carry down such particles (due to also containing ''no'' air, i.e., keeping it out to negate the normal {{w|Air shower (physics)|shielding and dissipating effect}} of the atmosphere on cosmic rays). However, this pipe would not only be a flight hazard, but also to ensure that no air molecules get in, the pipe would have to be similar to a space elevator, which would wreak a lot of havoc on LEO and MEO.
Whether a one-off cost or needing regular replacement, the setting up of such a tubular structure (a vertical air-proof pipe perhaps somewhere between 100 and 10000 kilometers high) would be technically challenging and has not ever been actually accomplished. The conditions for a quark–gluon plasma, albeit in limited quantities, at least have been fulfilled at {{w|CERN}}, with its 27 kilometer airless pipe that goes round within a vast circular tunnel.

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

:[Header:]
:How Water Filtration Works

:[A system of various devices between water pipes is shown.]
:[Input:]
:Well water
:[Labels of various devices:]
:Water softener
:Reverse osmosis
:Ultraviolet sterilization
:Autoclave
:Condenser
:Regular osmosis
:X-ray sterilization
:Carbon filter
:Neutron source
:Activated carbon filter
:Gamma ray sterilization
:Cosmic ray sterilization [On the device: "EeV γ"]
:Electrolysis [H2O split into O and H]
:Oxygen spallation [O becomes H]
:Ionizer [H split into + and -]
:Quark-gluon plasma chamber [+ and - become QGP]
:Hydrogenation [QGP becomes H]
:Nucleosynthesis [H goes through "P-P CNO" and becomes He and C, then through "Alpha" and becomes O]
:Reverse electrolysis
:[Output after devices:]
:Pure water
:[Second input, mixed with pure water:]
:Well water
:[Label:]
:Local minerals and probiotics added for taste and to support immune health
:[Final output:]
:To faucet

{{comic discussion}}

[[Category:Chemistry]]
[[Category:Physics]]
[[Category:Engineering]]

Talk:2983: Monocaster

2024-09-10T08:51:32Z

172.70.91.99:

Unicycles aren't (or at least aren't usually) chain-driven. I might try to fix that if my phone stops being so slow that it feels like I'm using a 90s PC to do this. Maybe a restart will help. Rebooting in 10, 9, 8... [[Special:Contributions/172.70.91.76|172.70.91.76]] 07:46, 10 September 2024 (UTC)
:I just went in and Actual Citation Needed it (seeing lower comment, when editor reloaded this page for me, forcing me to rewrite, that may have changed now).
:*It doesn't look like a chain-drive. Could be hub-geared, but not the same thing.
:*Chain-drive to raise the rider (most of the mass) up higher will ''raise'' the CoG.
:*'Underslung' chain-drive (see 1880s example, [[1673: Timeline of Bicycle Design|here]]?) has problems. Pedals hitting the ground would be one of them, unless your wheel was indeed significantly larger...
:*...and if it is (perhaps for better off-roading?), this intrinsically pushes up the CoG. Perhaps you are trying to lower it slightly, again, then. But you can't bring the saddle (and crotch!) lower than the now higher top of the wheel. ("Timeline of Bicycles" version ecepted, assumed assymetric?
:Add to that a few niggles about the bicycle. Not sure if intended to be a Moulton-style one (wheels maybe the classic 17", frame totally wrong) or a roadbike-style-ish one (frame relatively Ok, as drawn by someone not fully adhering to the design, maybe confused by some MTB variations, but clearly not in the ~27" wheel range, give or take). Of course, wheels are neither concentric nor circular, so depends a bit on which bits of the 'circles' are right for the intended arc and which bits ended up more casually doodled. [[Special:Contributions/172.70.91.99|172.70.91.99]] 08:51, 10 September 2024 (UTC)

Hmm, Randall missed an opportunity to put a Penny-Farthing in there... though I'm not sure how that would have categorised given that it has two wheels of different sizes. --[[Special:Contributions/172.68.205.178|172.68.205.178]] 08:19, 10 September 2024 (UTC)

Re: unicycles, the COG thing doesn't look right either, but I was distracted by a (thankfully) now-deleted troll comment before and actually fixing the description is beyond my skills, especially on so little sleep.[[Special:Contributions/172.69.43.184|172.69.43.184]] 08:35, 10 September 2024 (UTC)

2972: Helium Synthesis

2024-08-16T14:45:09Z

172.70.91.99: /* Explanation */ Analogy is not to familial inheritances, but to company holding structures

{{comic
| number = 2972
| date = August 14, 2024
| title = Helium Synthesis
| image = helium_synthesis_2x.png
| imagesize = 740x312px
| noexpand = true
| titletext = Our lawyers were worried because it turns out the company inherits its debt from the parent universe, but luckily cosmic inflation reduced it to nearly zero.
}}

==Explanation==
{{incomplete|Created by a BIG BANG NUCLEOSYNTHESIZER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic explores the challenges of obtaining {{w|helium}}. [[Hairy]] is leading a company meeting with [[Megan]], [[Cueball]], and [[Hairbun]], who are discussing the recurring problem of {{w|helium shortage}}s, a real-world issue due to helium's limited availability on Earth. Helium is a non-renewable resource extracted from {{w|natural gas}} deposits, and its scarcity can affect industries such as medical imaging, semiconductor manufacturing, scientific research, and party balloon supplies.[https://www.marketplace.org/2023/01/19/heliums-been-rising-in-price-and-its-bringing-businesses-down/] (See also [[2766: Helium Reserve]].)

Hairbun suggests investigating the origin of helium. Cueball's research reveals that most helium in the universe came from {{w|Big Bang nucleosynthesis}}, which occurred shortly after the {{w|Big Bang}} when the first elements were formed. (However, 99% of the helium here on Earth has been produced from the {{w|radioactive decay}} of {{w|uranium-238}} and {{w|thorium-232}} — which in turn came from {{w|r-process}} {{w|Supernova nucleosynthesis|nucleosynthesis}} inside merging {{w|neutron star}}s;[https://svs.gsfc.nasa.gov/13873/] see [[2826: Gold]] — into {{w|alpha particles}} identical to temporarily ionized helium, with only the remaining one percent originating from the Big Bang.)

Hairy assigns the team to figure out how to recreate Big Bang nucleosynthesis, which is not actually possible for a contemporary business organization.{{cn}} Nonetheless, the team builds a machine capable of it. While one might hope they would realize activating it may carry risks of obliterating them, along with at least all the closest galaxies, that disadvantage seems to grimly escape their attention in the tightly-focused drive towards their ill-fated mission.

The final panels show the creation of a second Big Bang followed by the next 14 billion years of that new universe, culminating with the same characters in an identical meeting, presumably having arisen from the same series of post-Big Bang events as in the original universe. They are facing the same predicament: helium shortages are still a problem, and they still need a reliable source. That such an extreme solution didn't actually solve the problem shows the impracticality of their plan, suggesting that some problems are too complex or vast to solve through uncritical brainstorming by corporations.

The title text is a wordplay on the two concepts of {{w|cosmic inflation}} and {{w|monetary inflation}}. In economics, monetary inflation is the rate at which the cost of things increases over time (one can also think of this as the value of money falling). If a debt is arranged on favorable terms, such that the interest on it turns out to be less than this rate, the value of that debt reduces over time. Cosmic inflation is a theory in cosmology that describes the rapid expansion of the universe just after the Big Bang. The joke imagines the original company as having incurred a significant debt (perhaps as a result of the costs of building the Big Bang machine), which has now been inherited by its subsidiary. Somehow, thanks to the effect of cosmic inflation, this debt was diluted (perhaps ''physically'' across the effectively infinite vastness of space), reducing it to [https://www.accum.se/~ola/hitchhik.htm nothing]. (See also [[2688: Bubble Universes]].) This is not really how debt works. However, since all the companies in the new universe are presumably effective subsidiaries of the original parent company, perhaps each of them would have inherited a negligible portion of its debt.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Hairy sits on an office chair at the head of a conference table and has his hands on the table, with Cueball and Megan also at the table.]
:Hairy: These helium shortages every few years are such a pain.
:Hairy: Our company needs a reliable source of helium.

:[The same situation, but now Hairbun is also seen at the table on the left side of Cueball. Cueball holds a cellphone in his left hand, which Megan looks at.]
:Hairbun: Where does helium come from, anyway?
:Cueball: Hmm, apparently most of it is from "Big Bang nucleosynthesis"?
:Hairy: Well, let's figure out how to do that.

:[Hairy, Megan and Hairbun are working on a large machine labeled "Big Bang Nucleosynthesis," with Megan holding its wired control device in her left hand.]

:[Two panels depict another Big Bang, followed by various stages of cosmic development, including galaxies and planets forming, shown in white on a black background.]

:[The scene returns to the same conference room setup as before, with the characters in the same positions. Text at the top reads: "14 Billion Years Later."]
:Hairy: These helium shortages every few years are such a pain.
:Hairy: Our company needs a reliable source of helium.

{{comic discussion}}
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics with inverted brightness]]
[[Category:Cosmology]]
[[Category:Physics]]
[[Category:Recursion]]

2971: Celestial Event

2024-08-15T08:46:10Z

172.70.91.99: /* Explanation */

{{comic
| number = 2971
| date = August 12, 2024
| title = Celestial Event
| image = celestial_event_2x.png
| imagesize = 471x300px
| noexpand = true
| titletext = If we can get a brood of 13-year cicadas going, we might have a chance at making this happen before the oceans evaporate under the expanding sun.
}}

==Explanation==
{{incomplete|Created by a CURSED SHOP THAT APPEARS EVERY FOUR POINT THREE BILLION YEARS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic highlights the extreme rarity of witnessing multiple special events—{{w|aurora}}s, {{w|Solar_eclipse#Total_eclipse|total solar eclipses}}, {{w|Great_Comet|great comets}}, and {{w|Periodical cicadas|17-year cicada emergences}}—all occurring simultaneously in the same location. It calculates that such an event would happen only once every 4.3 billion years, a time span comparable to the age of the Earth. The comic was posted shortly after some people reported seeing auroras in conjunction with the {{w|Perseids meteor shower}}.[https://www.msn.com/en-us/weather/topstories/the-2024-perseid-meteor-shower-and-northern-lights-overlapped-in-a-rare-cosmic-display-see-photos-of-the-dazzling-event/ar-AA1oJKKC]

[[Randall]] estimates that total solar eclipses occur once every 350 years at a given location, a value close to the 320-year interval for his hometown of Boston, Massachusetts, based on [https://eclipse.gsfc.nasa.gov/JSEX/JSEX-index.html NASA's data.] The calculation assumes that these events occur independently and that their probabilities remain constant over time, leading to the improbable result. However, this is a simplification, as factors like orbital mechanics and atmospheric conditions are not entirely random. Randall also includes a 50% chance of clear skies, which further reduces the odds of witnessing all events together. The comic exaggerates the difficulty of this happening, emphasizing that these conditions align less often than Earth's lifespan, suggesting such a celestial spectacle might only occur once before Earth becomes uninhabitable.

The title text humorously suggests using 13-year cicadas instead of 17-year ones to improve the odds, reducing the interval to 3.29 billion years. This idea, along with the possibility of weather manipulation, reflects Randall's satirical take on humanity's desire to control or predict natural phenomena, even when the timescales involved are beyond human comprehension. Earth's oceans may evaporate in about a billion years [https://www.sciencedaily.com/releases/2013/12/131216142310.htm], adding a layer of urgency and humor to the idea of witnessing this "super-event" before life on Earth ceases to exist.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Approximate frequency in my area

:Active northern lights: 20 days per solar cycle

:A naked-eye "Great Comet": 2 months every 50 years

:Total eclipse: once every 350 years

:Clear skies: 50% of the time

:17-year cicada emergence: 2 months every 17 years

opening bracket

20 days over 11 years multiplied by

2 months over 50 years multiplied by

1 over 350 years multiplied by

one half multiplied by

2 months over 17 years

closing bracket to the power of -1

equals 4.3 billion years

:[Caption below the panel:]
:Every 4 billion years or so, my neighborhood gets to see a ''really'' spectacular show.

{{comic discussion}}

[[Category:Astronomy]]
[[Category:Solar eclipses]]
[[Category:Time]]
[[Category:Animals]]

2971: Celestial Event

2024-08-15T08:44:09Z

172.70.91.99: /* Explanation */

{{comic
| number = 2971
| date = August 12, 2024
| title = Celestial Event
| image = celestial_event_2x.png
| imagesize = 471x300px
| noexpand = true
| titletext = If we can get a brood of 13-year cicadas going, we might have a chance at making this happen before the oceans evaporate under the expanding sun.
}}

==Explanation==
{{incomplete|Created by a CURSED SHOP THAT APPEARS EVERY FOUR POINT THREE BILLION YEARS - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic highlights the extreme rarity of witnessing multiple special events—{{w|aurora}}s, {{w|Solar_eclipse#Total_eclipse|total solar eclipses}}, great comets, and {{w|Periodical cicadas|17-year cicada emergences}}—all occurring simultaneously in the same location. It calculates that such an event would happen only once every 4.3 billion years, a time span comparable to the age of the Earth. The comic was posted shortly after some people reported seeing auroras in conjunction with the {{w|Perseids meteor shower}}.[https://www.msn.com/en-us/weather/topstories/the-2024-perseid-meteor-shower-and-northern-lights-overlapped-in-a-rare-cosmic-display-see-photos-of-the-dazzling-event/ar-AA1oJKKC]

The events listed include total solar eclipses, which [[Randall]] estimates occur once every 350 years at a given location, a value close to the 320-year interval for his hometown of Boston, Massachusetts, based on [https://eclipse.gsfc.nasa.gov/JSEX/JSEX-index.html NASA's data.] The calculation assumes that these events occur independently and that their probabilities remain constant over time, leading to the improbable result. However, this is a simplification, as factors like orbital mechanics and atmospheric conditions are not entirely random. Randall also includes a 50% chance of clear skies, which further reduces the odds of witnessing all events together. The comic exaggerates the difficulty of this happening, emphasizing that these conditions align less often than Earth's lifespan, suggesting such a celestial spectacle might only occur once before Earth becomes uninhabitable.

The title text humorously suggests using 13-year cicadas instead of 17-year ones to improve the odds, reducing the interval to 3.29 billion years. This idea, along with the possibility of weather manipulation, reflects Randall's satirical take on humanity's desire to control or predict natural phenomena, even when the timescales involved are beyond human comprehension. Earth's oceans may evaporate in about a billion years [https://www.sciencedaily.com/releases/2013/12/131216142310.htm], adding a layer of urgency and humor to the idea of witnessing this "super-event" before life on Earth ceases to exist.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Approximate frequency in my area

:Active northern lights: 20 days per solar cycle

:A naked-eye "Great Comet": 2 months every 50 years

:Total eclipse: once every 350 years

:Clear skies: 50% of the time

:17-year cicada emergence: 2 months every 17 years

opening bracket

20 days over 11 years multiplied by

2 months over 50 years multiplied by

1 over 350 years multiplied by

one half multiplied by

2 months over 17 years

closing bracket to the power of -1

equals 4.3 billion years

:[Caption below the panel:]
:Every 4 billion years or so, my neighborhood gets to see a ''really'' spectacular show.

{{comic discussion}}

[[Category:Astronomy]]
[[Category:Solar eclipses]]
[[Category:Time]]
[[Category:Animals]]