explain xkcd - User contributions [en]

3078: Anchor Bolts

2025-04-22T06:17:06Z

BeeVee: /* Explanation */ typo

{{comic
| number = 3078
| date = April 18, 2025
| title = Anchor Bolts
| image = anchor_screws_2x.png
| imagesize = 381x326px
| noexpand = true
| titletext = The biggest expense was installing the mantle ducts to keep the carbonate-silicate cycle operating.
}}

==Explanation==
{{incomplete|Created by an AUTOMATIC SUBLIMATOR. Don't remove this notice too soon. Need to rephrase a section, see the talk page.}}

The comic displays a cross-section of a subduction zone, with an anchor bolt connecting the two tectonic plates. {{w|anchor bolt|Anchor bolts}} are used to secure an item in place, for instance to attach a building to its foundation. In earthquake prone areas, anchor bolts are often used to secure furniture so it will be less hazardous during a tremor.

{{w|Subduction}} is a geologic process in which two {{w|Plate tectonics|plates}} of planetary {{w|lithosphere}} converge, and one is dragged under the other. The Earth's lithosphere is divided into tectonic plates. They slowly move across the surface at a few centimeters per year, although the rate is nonuniform across plates. Where they collide, the denser plate gets dragged under the less dense plate, in a process called subduction. {{w|Earthquake|Earthquakes}} are common at subduction zones, and subduction can also lead to volcanic activity. An "anti-subduction anchor bolt" would effectively stop the process of subduction and the movement of plate tectonics as a whole.{{citation needed}}

A round head bolt is screwed in through both the oceanic lithosphere and the continental crust from the bottom up, with a plain washer on either side, and a wing nut tightened at the surface. Washers are present to prevent the bolt and the wing nut from sinking into the crust, by distributing the forces over larger areas. There are several concerns not addressed in the comic with such a design. The implication that the bolt is being screwed in from the mantle side would imply that a very large bolt head was operated from inside the mantle. (There are types of nut-and-bolt system that might be easier to deploy, such as {{w|toggle bolt}}s and {{w|Molly (fastener)|mollys}}. These would have the bolt head on the Earth's surface, rather than in the mantle, and use a spreading "nut" inside the Earth. They wouldn't require conducting enormous operations from below, "merely" a large hole bored from above.) As of the time of posting of the comic, {{w|Kola Superdeep Borehole|humans have not drilled a hole through a continental crust}}, still less deployed large vehicles in the mantle.{{Citation Needed}} In addition, the presence of wing nuts, fasteners that are designed to be able to be screwed in by hand, implies work done by a larger being that has appendages able to use the wing nut. The bolt itself would be a technological challenge, as well. It would need to be made to withstand the temperature of Earth's mantle, around 1000°C near the surface. At these temperatures, most commercial stainless steel used to manufacture bolts would experience noticeable strength losses. The bolt would need be around 50 km long. Moreover, as subduction zones move parallel to each other, the construction would have to withstand high shear forces, something that a bolt is rather unsuited to compared to other tools, such as rivets. On top of that, ways to alleviate stress must be sought out as if the bolt fails, it could produce a highly amplified earthquake.

In the short term, earthquakes and volcanic eruptions are typically bad for those living nearby, and thus ways to prevent them happening might reduce economic risks in those areas. However, volcanic eruptions deposit nutrients in the surrounding area, enriching soils. Volcanos also release gasses. The vents mentioned in the title text might replenish the nutrients and gasses, replacing the benefits of eruptions. Earthquakes sometimes trigger {{w|tsunami|tsunamis}}, which create or modify beaches, and redistribute nutrients from bays and estuaries across coastal plains. So, while the immediate effects of eruptions and earthquakes can be disruptive, they also enrich the environment. Areas at risk from these "disasters" are also attractive and enriched as a result of these same events.

When plates collide but do not subduct, they often uplift, thickening or raising the crust. The {{w|Himalayas|Himalaya}} mountains, are an example. Tectonic plates spread apart as new lithosphere is formed at ridges, most of which occur under oceans. If spreading continued, but subduction was prevented by the system of anchors pictured in this cartoon, there would likely be new areas of uplift. If positioned appropriately, the mantle ducts, mentioned in the title text, might slow or stop the spreading, reducing uplift.

The title text references the {{w|Carbonate–silicate cycle|carbonate-silicate geochemical cycle}}. Briefly, subduction and subsequent heating of the global crust restores carbon dioxide and silicate rocks to the planetary surface, countering the effects of carbonate deposition and silicate rock weathering. Anchor bolts sufficient to stop plate tectonics would also stop the carbonate-silicate cycle, leading to unexpected, and likely unwelcome, changes in the surface geosphere and biosphere. (Arguably, if the carbonate cycle alone could be paused, it might be a means of reducing the amount of carbon dioxide in the biosphere.) To restore the cycle by an unknown mechanism, "mantle ducts" have been installed as part of the planet-wide plate anchoring system. It is stated that the mantle duct installation was the most expensive part of the project, implying greater intellectual and technical challenges than the already-massive ones associated with anchor-bolt design and deployment.

This project would presumably render [[Beret Guy]]'s [[1388|Subduction License]] worthless.

==Transcript==
:[Panel shows Randall's usual illustration of a subduction zone: a tectonic plate subducting from the left side of the panel with water above it, and a mountain range forming on the right side of the panel on the other tectonic plate. Beneath each tectonic plate is the asthenosphere. The main difference between this image and others like it is that there is a bolt shown attaching the plates together in the subduction zone. The head of the bolt is shown in the asthenosphere below the subducting plate. There are two washers displayed, one between the bolt head and the subducting plate and one above the other above the upper plate on the side of a smaller mountain. A wing nut is positioned above this washer, with part of the bolt sticking out above the nut, higher than the tallest mountains in the panel]

:[Caption below the panel:]
:Good news: Geophysicists are '''''finally''''' installing Earth's required anti-subduction anchor bolts.

==Trivia==
In the [https://www.explainxkcd.com/wiki/images/archive/0/00/20250419063115%21anchor_screws_2x.png original version of the comic], the caption said "anti-subduction anchor '''screws'''" instead of "anti-subduction anchor '''bolts'''". The title of the comic was also changed, from "Anchor Screws" to "Anchor Bolts". The original comic image and title can be seen on an [https://web.archive.org/web/20250419024242/https://xkcd.com/3078/ archived version] of the [https://xkcd.com xkcd.com] site. The fastener illustrated is indeed a {{w|Bolt (fastener)|bolt}} (with a {{w|Wingnut (hardware)|wing nut}}), not a screw. A screw has a pointed end and is drilled into a hole that is smaller than the diameter of the screw; the pressure caused by its {{w|screw thread|thread}} and screw head binds two objects together. A screw does not need a nut to go with it.

A bolt has a flat end, and it goes into a hole that is larger than the diameter of the bolt; it needs a nut which, when fixed onto the bolt and tightened, together with the head creates the pressure that binds the two objects together. Because a nut is used to create pressure, "bolt" is a more correct term than "screw", although it is very common to talk of 'screws' for [[1474: Screws|screw-headed]] bolts which attach panels (with non-threaded holes) against a substrate which incorporates a 'nut-like' threaded hole within it (or a nut encapsulated and held non-rotating in the backing plate's recess), even though they are also flat-faced at the thread-end and not self-tapping.

Or, for a differently worded definition, {{w|Screw#Differentiation between bolt and screw|see here}}.

{{comic discussion}}

[[Category:Subduction]]
[[Category:Geology]]
[[Category:Comics edited after their publication]]

Talk:3077: de Sitter

2025-04-17T14:37:56Z

BeeVee:

the titletext still needs an explanation, but i'm not sure i get the connection to conformal field theory; i suspect it has to do with the explosive rate at which hyperolic space seems to "expand" when travelled through, as a pun on the club expanding at a similar rate? - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 07:01, 17 April 2025 (UTC)
[[Special:Contributions/162.158.90.137|162.158.90.137]] 07:21, 17 April 2025 (UTC) I think it's alluding to {{w|AdS/CFT correspondence}}, which I think is a string theory thing.

In hyperbolic space, parallel lines DON'T meet when extended, and in elliptic space they DO. Also, the rotation thing looks strange. In any of the basic geometries you have 360 degrees in a circle. The sum of angles in triangle will be different (smaller than 180 in hyperbolic space, larger in elliptic space). [[Special:Contributions/172.68.213.151|172.68.213.151]] 07:58, 17 April 2025 (UTC)
* Agreed. I went and changed it. Though technically, the stuff about parallel lines is still wrong. Parallel lines don't meet by definition, and spherical geometry doesn't have them. Maybe someone can add a better explanation? [[User:DanielLC|DanielLC]] ([[User talk:DanielLC|talk]]) 09:19, 17 April 2025 (UTC)

The yellow wood is a hyperbolic space.[[Special:Contributions/141.101.99.4|141.101.99.4]] 08:08, 17 April 2025 (UTC)

maybe a pun on "babysitters are not welcome here" [[User:Translated ORK|Translated ORK]] ([[User talk:Translated ORK|talk]]) 09:08, 17 April 2025 (UTC)

Fun Fact: the german version of Anti-de Sitter space in wikipedia refers to a [Randall–Sundrum model|https://en.wikipedia.org/wiki/Randall%E2%80%93Sundrum_model]

"...less than 180° in a full rotation"

Shouldn't this be either "...less than 360° in a full rotation" (or perhaps "...the angles of a triangle add up to less than 180°").

[[Special:Contributions/172.69.186.206|172.69.186.206]]

I've started to explain the title-text, but not well. I don't really understand either of these concepts.

I don’t really know how to explain it well, but the wikipedia page on these spaces says it’s negative SCALAR curvature. That is a different concept from what is currently being explained here. The intuitive dimension of curvature applies only to 2-dimensional spaces. In higher dimensions you can look at 2D-slices, and the curvature of those is called the sectional curvature. Scalar curvature is then something of an average of those. Notably, if scalar curvature is negative, that does not mean sectional curvature necessarily always is (though perhaps the higher symmetry of these spaces enforces this? I’m really not sure). The main way you can measure scalar curvature is by calculating the volume of a sphere of radius r – if the scalar curvature is 0 it’ll be the usual formula from Euclidean space, but if it’s negative, then for sufficiently small radii the volume will be bigger than expected (intuitively, more space gets crammed around each point). Feel free to incorporate this into the article.

I thought it might be a play on "housesitter" and the fact that anti and de can denote negatives, but I'm not sure how [[User:BeeVee|BeeVee]] ([[User talk:BeeVee|talk]]) 14:37, 17 April 2025 (UTC)

3018: Second Stage

2024-12-01T10:09:31Z

BeeVee: /* Explanation */ typo

{{comic
| number = 3018
| date = November 29, 2024
| title = Second Stage
| image = second_stage_2x.png
| imagesize = 740x272px
| noexpand = true
| titletext = Hmm, they won't do in-flight delivery, so let's order a new first and second stage to our emergency landing site and then try to touch down on top of them to save time.
}}

==Explanation==
{{incomplete|Created by a BLUE ORIGIN DELIVERY DRIVER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In this comic, two people have lifted off in a staged launch vehicle without their second stage installed. This is unlikely to happen in real life, because rocket launches are thoroughly planned and checked, and the lack of an entire stage would be glaringly obvious to anyone who is part of the project.

Staging in rocketry refers of the segmentation of a launch vehicle into distinct, separable modules, each one with an independent engine and fuel supply. This is practiced for two critical reasons: firstly, different engine designs work better at different altitudes, so you'd want to use one engine type deep in the atmosphere and a different engine once you get to space; and because, since you only need one of those engines at once, it'd be better to simply expend the first engine(s) and its fuel tank once you no longer need it. By getting rid of that useless mass, you can go farther using the same amount of fuel. A launch vehicle that does not employ staging is called an SSTO (Single-Stage-To-Orbit), but none of them have been successful due to the technical challenges.

As Pilot 1 calls to fire the second stage, Pilot 2 is initially confused and asks if a second stage was needed. Pilot 1 confirms that there was supposed to be a second stage, and thought that it was the Pilot 2's responsibility to install and confirm there was a second stage. When both pilots realize there is no second stage, Pilot 2, naturally, thinks he can order one on Amazon with same day delivery (though Amazon typically doesn't sell space ship stages - at least not with same day delivery [citation needed]). He then has difficulty picking an address zip code as they are likely traveling too high above the ground and too fast to be in a single postal area for long enough for the delivery to take place. The joke is likely poking fun at people who forget to pack certain items when going on road trips or vacation, and rely on Amazon to deliver replacements to them. There is also humor to be found in this rocket apparently being designed, built, and piloted by only two people-- in real life, the construction of a rocket, especially a manned one, involves thousands of people, and the pilots do not do the designing themselves.

The comic also alludes to a not-so-distant future when space travel is a much more mundane endeavor. If companies such as SpaceX succeed in their mass-production and launch cadence goals, one could imagine a scenario where rocket parts become standardized and easily replaceable-- similarly to how it is easy today to replace a car's tire or fill its fuel tank if you get stranded on a highway.

In the title text, Pilot 2 concludes that in-flight delivery won't be possible but proposes to have a new first and second stage delivered to their emergency landing site so they can pick them up and continue on their launch without stopping.

This is not the first time Randall discusses the idea of a mid-flight delivery. This [https://what-if.xkcd.com/149/ What If?] explanation attempts to answer if it possible to have pizza delivered to you, by a bird, while flying on a commercial airliner.

== Trivia ==
*The rocket, though apparently at least one segment short, appears to be substantially taller than the launch tower of the pad, which is a strangely incongruous detail. Unless the real rocket support is an angled back "hard spine" structure that has been rotated out of the way and down into the exhaust-flume/flame-trench quenching system. Since the voices are coming from what appears to be a separate module at the top of the rocket, it may be that the ''shell'' of the second stage is present, but not the hardware or fuel. Alternatively, propellant may have been loaded into the second stage, but engines were never installed.


==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A multi-stage rocket, with a capsule on top, is lifting-off the ground from a launchpad, at least two rocket nozzles are visibly producing a flame, and the pad is surrounded with smoke and/or steam from the blast suppression system. A voice comes from the capsule at the top.]
:We have liftoff.

:[The first stage separates from the rest of the rocket, part way through the roll-program. There are no obvious engines standing out from the 'second stage' (or extended payload trunk) lower shroud.]
:Main engine cutoff.
:Stage separation confirmed.
:We are go for second stage burn.

:Second stage?

:Yes.
:...What?

:[The first stage and the rest of the rocket are drifting apart in apparent freefall. No rocket is firing and the background does not seem to indicate that this view is beyond the atmosphere.]
:We were supposed to have a second stage?

:...Yes!

:Did '''''you''''' set up a second stage?

:I thought '''''you''''' were handling staging!

:Oh no.

:[They continue to drift apart slowly.]
:Okay, don't panic.
:Lemme see if we can order a stage online for same-day delivery.

:''Sigh''.

:Hey, what zip code should I put? Ours keeps changing.

{{comic discussion}}

[[Category:Space]]
[[Category:Rockets]]

3018: Second Stage

2024-12-01T10:08:50Z

BeeVee: /* Explanation */

{{comic
| number = 3018
| date = November 29, 2024
| title = Second Stage
| image = second_stage_2x.png
| imagesize = 740x272px
| noexpand = true
| titletext = Hmm, they won't do in-flight delivery, so let's order a new first and second stage to our emergency landing site and then try to touch down on top of them to save time.
}}

==Explanation==
{{incomplete|Created by a BLUE ORIGIN DELIVERY DRIVER - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In this comic, two people have lifted off in a staged launch vehicle without their second stage installed. This is unlikely to happen in real life, because rocket launches are thoroughly planned and checked, and the lack of an entire stage would be glaringly obvious to anyone who is part of the project.

Staging in rocketry refers of the segmentation of a launch vehicle into distinct, separable modules, each one with an independent engine and fuel supply. This is practiced for two critical reasons: firstly, different engine designs work better at different altitudes, so you'd want to use one engine type deep in the atmosphere and a different engine once you get to space; and because, since you only need one of those engines at once, it'd be better to simply expend the first engine(s) and its fuel tank once you no longer need it. By getting rid of that useless mass, you can go farther using the same amount of fuel. A launch vehicle that does not employ staging is called an SSTO (Single-Stage-To-Orbit), but none of them have been successful due to the technical challenges.

As Pilot 1 calls to fire the second stage, Pilot 2 is initially confused and asks if a second stage was needed. Pilot 1 confirms that there was supposed to be a second stage, and thought that it was the Pilot 2's responsibility to install and confirm there was a second stage. When both pilots realize there is no second stage, Pilot 2, naturally, thinks he can order one on Amazon with same day delivery (though Amazon typically doesn't sell space ship stages - at least not with same day delivery [citation needed]). He then has difficulty picking an address zip code as they are likely traveling too high above the ground and too fast to be in a single postal area for long enough for the delivery to take place. The joke is likely poking fun at people whom forget to pack certain items when going on road trips or vacation, and rely on Amazon to deliver replacements to them. There is also humor to be found in this rocket apparently being designed, built, and piloted by only two people-- in real life, the construction of a rocket, especially a manned one, involves thousands of people, and the pilots do not do the designing themselves.

The comic also alludes to a not-so-distant future when space travel is a much more mundane endeavor. If companies such as SpaceX succeed in their mass-production and launch cadence goals, one could imagine a scenario where rocket parts become standardized and easily replaceable-- similarly to how it is easy today to replace a car's tire or fill its fuel tank if you get stranded on a highway.

In the title text, Pilot 2 concludes that in-flight delivery won't be possible but proposes to have a new first and second stage delivered to their emergency landing site so they can pick them up and continue on their launch without stopping.

This is not the first time Randall discusses the idea of a mid-flight delivery. This [https://what-if.xkcd.com/149/ What If?] explanation attempts to answer if it possible to have pizza delivered to you, by a bird, while flying on a commercial airliner.

== Trivia ==
*The rocket, though apparently at least one segment short, appears to be substantially taller than the launch tower of the pad, which is a strangely incongruous detail. Unless the real rocket support is an angled back "hard spine" structure that has been rotated out of the way and down into the exhaust-flume/flame-trench quenching system. Since the voices are coming from what appears to be a separate module at the top of the rocket, it may be that the ''shell'' of the second stage is present, but not the hardware or fuel. Alternatively, propellant may have been loaded into the second stage, but engines were never installed.


==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[A multi-stage rocket, with a capsule on top, is lifting-off the ground from a launchpad, at least two rocket nozzles are visibly producing a flame, and the pad is surrounded with smoke and/or steam from the blast suppression system. A voice comes from the capsule at the top.]
:We have liftoff.

:[The first stage separates from the rest of the rocket, part way through the roll-program. There are no obvious engines standing out from the 'second stage' (or extended payload trunk) lower shroud.]
:Main engine cutoff.
:Stage separation confirmed.
:We are go for second stage burn.

:Second stage?

:Yes.
:...What?

:[The first stage and the rest of the rocket are drifting apart in apparent freefall. No rocket is firing and the background does not seem to indicate that this view is beyond the atmosphere.]
:We were supposed to have a second stage?

:...Yes!

:Did '''''you''''' set up a second stage?

:I thought '''''you''''' were handling staging!

:Oh no.

:[They continue to drift apart slowly.]
:Okay, don't panic.
:Lemme see if we can order a stage online for same-day delivery.

:''Sigh''.

:Hey, what zip code should I put? Ours keeps changing.

{{comic discussion}}

[[Category:Space]]
[[Category:Rockets]]

2286: 6-Foot Zone

2020-03-28T15:20:07Z

BeeVee: /* Explanation */ In France (and the UK, and perhaps others) the distance used is 2 m, so I updated the explanation

{{comic
| number = 2286
| date = March 27, 2020
| title = 6-Foot Zone
| image = 6_foot_zone.png
| titletext = Technically now it's a 34-foot zone.
}}

==Explanation==
{{incomplete|Created by 8 HORSES. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic is the 11th comic in a row in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus pandemic|2020 pandemic}} of the {{w|coronavirus}} - {{w|SARS-CoV-2}}.

This comic is about {{w|social distancing}}, a common practice to prevent the spread of the COVID-19 disease. It has been suggested to maintain 6 feet (i.e. 1.83 m - in countries with SI units it is ~1.5 m - France uses 2 m) of distance between yourself and other people, to prevent the transmission of respiratory droplets from you to others (or vice versa).

[[Randall]] takes this 6 feet of distance, and does calculations of the "area" of distancing, "border", population density, and "real estate value". With 6 feet of distance, these calculated variables are incorrect. Besides the radius of the body, only a radius of 3 feet has to be taken into account for a distance of 6 feet between two people. He finally culminates in determining the number of horses that could also fit in the space.

Randall's border length and approximate area calculations are based on a zone with an outside radius of approximately 6.8 feet or 82 inches (2.07 m), meaning that the person has a radius of approximately 0.8 feet or 10 inches (0.24 m).

The title text is a pun using the alternate definition of foot, noting that a human has two feet and a horse has four, so 8x4 + 2 = 34 feet.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Guide to the 6 foot Social Distancing Zone
:Profile image of person with 6 foot distance measurements on both sides
:Overhead image of person within a roughly circular shape extending 6 feet in all directions from the person. The dimensions of the person account for the non-circular shape.
:Approximate area: 145 square feet
:Border length: 43 feet
:Population density: 190,000 people/square mile
:Value at NYC real estate price per square foot: $195,000
:Maximum number of horses that could fit inside it with you, estimated using the dimensions in the US Forest Service Equestrian Design Handbook: 8
{{comic discussion}}

[[Category:COVID-19]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Animals]]

Talk:2009: Hertzsprung-Russell Diagram

2018-06-21T14:48:33Z

BeeVee:

How the heck is a lava cake more luminous than a campfire? {{unsigned ip|108.162.219.28}}
:It's Lava Lake, as in a large puddle of lava.[[User:Cgrimes85|Cgrimes85]] ([[User talk:Cgrimes85|talk]]) 15:45, 20 June 2018 (UTC)
:: Now the real question is, Why isn't lava cake included on the diagram?!?! [[User:Veleek|Veleek]] ([[User talk:Veleek|talk]]) 23:54, 20 June 2018 (UTC)
:This is the best misreading that I've seen in a while! [[User:Quantum7|Quantum7]] ([[User talk:Quantum7|talk]]) 07:56, 21 June 2018 (UTC)

As it's a logarithmic scale, is it more correct to say the plot been expanded to 1 on both axes? [[User:Cgrimes85|Cgrimes85]] ([[User talk:Cgrimes85|talk]]) 15:47, 20 June 2018 (UTC)

It seems Randall thinks an astronomer is about as bright as a lightbulb, probably due to the Hertzsprung-Russell diagram itself! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 15:52, 20 June 2018 (UTC)
:A daily food consumption of average human is about 100W when spread out over 24 hours
::It might actually be about that bright, but in the infrared spectrum. http://elte.prompt.hu/sites/default/files/tananyagok/InfraredAstronomy/ch01s04.html [[Special:Contributions/108.162.246.89|108.162.246.89]] 20:54, 20 June 2018 (UTC)
:But they are no where near as hot!
::You seem to overestimate the attractiveness of most lightbulbs. I've only seen a few that I would consider really hot.
[[Special:Contributions/172.69.198.10|172.69.198.10]] 20:57, 20 June 2018 (UTC)
:::And size; Remember that this type of chart is for comparing total luminosity to surface temperature, & although light bulbs get hot, they're usually nowhere near the surface area of an astronomer.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

While wattage is used as an informal proxy for bulb brightness, there is not a 1-to-1 relationship between power consumption and light output. Incandescent bulbs in the United States were commonly labeled with both watts consumed and lumens output to aid consumers in choosing efficient bulbs.
:"Were"? When? These days the lamp itself usually only states volts & watts, & you're lucky if even the box states lumens. My personal least-favorite is "60w equivalent" with no color temperature & no luminosity listed.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

{{w|Ivanpah Solar Power Facility|Ivanpah}} doesn't have a salt tank. Presumably he meant the boiler, and/or was confusing it with {{w|Crescent Dunes Solar Energy Project|Crescent Dunes}}.
[[User:Wwoods|Wwoods]] ([[User talk:Wwoods|talk]]) 17:29, 20 June 2018 (UTC)
:Thank you! That had me scratching my head. I bet he was thinking of Crescent Dunes. Should this be noted in the Explanation?[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

I understand the explanation, but what's the joke?

The title text says "The Hertzsprung-Russell diagram is located in its own lower right corner, unless you're viewing it on an unusually big screen." But it's clearly on the top left corner... Am I missing something? [[Special:Contributions/108.162.219.106|108.162.219.106]] 18:47, 20 June 2018 (UTC)

:Why would it be at the top left...? The diagram itself is not particularly luminous, so would not be at the top, and its apparent temperature is quite low, so it would not be on the left.

::The joke is that while these type of graphs are typically used for illustrating the output of stars in relation to their age; Randall has extended its range to apply it to planets, boats, whales, & astronomers. Most items in the lower right are neither very luminous (compared to the total luminosity of a star) nor very hot (as compared to a star) & certainly their output on either scale does not bear a reliable correlation to their age. Randall is once again weighing things with the wrong measuring stick, so to speak.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

Why is a blue whale considered more luminous than a campfire? Blue whales don't generate any light.
:It would if your took it out of the water (to reduce convective losses), but it would emit in the infrared. The 78 kW cited here would equate to 588 million kcal of krill per year. That's in the ballpark of other estimates I found (e.g. 490 million[https://www.washingtoncitypaper.com/columns/straight-dope/article/13041278/straight-dope-does-the-average-american-use-more-energy-than]). I agree that this is one of the more surprising facts to find on this chart. --[[User:Quantum7|Quantum7]] ([[User talk:Quantum7|talk]]) 08:10, 21 June 2018 (UTC)
:: Size counts for a lot of that. By ounce, a campfire would be hotter, but these graphs go by total, not per-ton of mass.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

In one of the interesting parts of this diagram not that many mundane objects (or at least smaller than earth objects) are much hotter than most stars (surface temperature)... Not mentioned now.--[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 20:33, 20 June 2018 (UTC)
:I'm beginning to think the Explanation should highlight the fact that these graphs go by total output, not output per kilogram or anything relative like that. Body temperature of a blue-whale is almost certainly higher than the average temperature of a cruise ship, but a cruise ship is *much* bigger, thereby almost certainly outputting more heat. That said, I'm pretty sure these charts are only supposed to go by ''surface'' thermal output, which could throw a lot of these listings way off. Anyone know what the ''surface'' temperature of a blue-whale is? I've never seen one shown in infrared.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

I think the current explanation is still taking some of the graph too literally, thereby missing some of the jokes. After all, Randall creates comics, sometimes using innuendo or subtlety to make a point. I still think some of the items on the graph are plotted using luminosity as a measure of "brightness" in the sense of smartness. No offense intended, but he must have had a reason for including France below the planets and the blue whale above the astronomer. Furthermore, the title text is likely talking about the actual HR diagram not being very "bright" in the same way the astronomer is in the lower-right corner of the graph, except when it is displayed on a jumbotron. If you're an astronomer, you might not like hearing this, but the meaning of the HR diagram is difficult to grasp correctly. To leave out any mention of smartness is likely missing the most significant jokes in the comic. Please feel free to disagree, but remember it's still just a comic! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 00:37, 21 June 2018 (UTC)

: More specifically to my point, this part of the explanation
:: "the title text notes that the screen displaying the diagram would probably be plotted..."
: is not correct. The title text states the diagram itself would probably be plotted in the lower-right corner, not the screen displaying it - the screen was only related to the second part of the title text! This IS the primary joke in the comic and likely why Randall is making fun of it in the first place. This is also likely the reason for the astronomer to ALSO be plotted in this corner - I doubt that is just a coincidence. Maybe Randall was too subtle for his point to get through to readers! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 04:37, 21 June 2018 (UTC)

: Just in case I'm also being too subtle, I think Randall is saying that the HR diagram is neat to look at (as in really cool) but also stupid (as in not very bright), putting it in the lower-right corner of itself (cool and dim)! There, I said it! [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 04:45, 21 June 2018 (UTC)

::I believe it is definitely about total luminosity & thermal output, ''not'' "brightness" as a measure of intelligence. France is below the planets because it has much less total surface area & thereby less luminosity than the planet itself. If the graph listed by average luminosity per square inch, France would be higher than Earth. There is no joke about intelligence here, only that total luminosity & total heat output are not reliably linked to the age of non-stellar scale objects.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

How come this diagram says an LED bulb is hotter than a lightbulb, and both are hotter than a campfire? That doesn't seem right. [[User:YM Industries|YM Industries]] ([[User talk:YM Industries|talk]]) 01:49, 21 June 2018 (UTC)
:The confusion is coming from the fact that the arrow at the top is pointing toward lower temperatures. I'm not sure if this is intentional, or if it is a mistake, but seems to be confusing a lot of people (including myself until I read the actual numbers)[[User:Probably not Douglas Hofstadter|Probably not Douglas Hofstadter]] ([[User talk:Probably not Douglas Hofstadter|talk]]) 03:09, 21 June 2018 (UTC)
:: I noticed that the arrow was pointing in a confusing direction, but LED bulb is to the left of the campfire. The diagram clearly says it's hotter. I'm very confused by this comic. [[User:YM Industries|YM Industries]] ([[User talk:YM Industries|talk]]) 05:22, 21 June 2018 (UTC)

: The location of the LED and Lightbulb temperatures may be related to the actual light source points of these objects (diode junction and wire filament) rather than the outer shells that we can touch. I don't know enough about their internal temperatures to say for sure, but that might explain their positions. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 05:05, 21 June 2018 (UTC)

:Worked it out, it's referring to the colour temperature. [[User:YM Industries|YM Industries]] ([[User talk:YM Industries|talk]]) 05:24, 21 June 2018 (UTC)
::Right. The color temperature of an LED bulb can be much higher than a blackbody of the same power and area because it emits in only a small spectral region.[[Special:Contributions/108.162.238.47|108.162.238.47]] 05:32, 21 June 2018 (UTC)
:::'''''A pun! That's another joke; Should definitely be noted in the transcript.''''' Also, if he ''were'' referring to internal temperatures, not surface temperatures, it would be the only place in this chart he seems to have done so. The other listings are consistent with surface temperatures, not average internal temps.[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 14:25, 21 June 2018 (UTC)

I'm pretty sure there shouldn't be a table in the transcript? I've moved it, but now the table needs to be filled and the transcript needs some work. [[User:Herobrine|Herobrine]] ([[User talk:Herobrine|talk]]) 03:10, 21 June 2018 (UTC)

Venus' temperature is correct. Randall is using planetary equilibrium temperature <ref>https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature</ref> [[User:Astronorn|Astronorn]] ([[User talk:Astronorn|talk]]) 04:56, 21 June 2018 (UTC)

Seriously, can we get a mention that this graph relates to ''total'' output by surface area, not relative output by mass or anything like that? Obviously per square inch, a campfire is much more luminous than a whale, but the whale gives off more radiation in total due to its greater surface area. The distinction seems to be a source of confusion a lot of people.

The France entry might relate to the fact that our commune here in France (Pessac, 33) now turns off its streetlights between 0100-0500; and there are many communes that do the same or use more sophisticated schemes, like motion sensors or partial extinction, and turning off lighted signage for shops, etc.. [[User:BeeVee|BeeVee]] ([[User talk:BeeVee|talk]]) 14:48, 21 June 2018 (UTC)