2336: Campfire Habitable Zone

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Campfire Habitable Zone
Oh no, my marshmallow became tidally locked!
Title text: Oh no, my marshmallow became tidally locked!


This comic plays on the concept of the astronomic "habitable zone" applied at the scale of people sitting around a campfire.

The habitable zone of a star is the range of distances in which a planet might support liquid water, and hence life in the only form that we currently know of (as an allusion to the "not too hot, not too cold, but just right" of the related children's story, the habitable zone is also commonly known as the "Goldilocks zone"). If the planet is too close to the star, then the amount of stellar radiation would be too great, causing the water to boil; too far from the star, and the planet doesn't have enough radiation, causing the water to freeze (although for life to actually exist, the planet itself must also have the right mass in order to maintain a life-compatible atmosphere and meet other such requirements). For our Sun, the habitable zone is estimated to range from about 0.38 to 10 astronomical units, where 1 astronomical unit is the distance from the Sun to the Earth.

Marshmallow toasting is a popular camping activity in which people place a marshmallow (a soft, sugary blob made of gelatin and covered in corn starch) on a stick and over/near a fire. As the marshmallow cooks, the inside becomes gooey while the outside becomes crispy (perhaps slightly charred and maybe even burned, depending on the toaster's preference), making it tastier via caramelization and the Maillard reaction.

In the context of the campfire, a similar "habitable zone" is posited by Randall to exist: a zone which is close enough to the fire such that the person can comfortably toast marshmallows, presumably on a stick of reasonable length (the ones in the comic seem to be about 1.5 times an arm's normal reach), yet far enough such that the person is not uncomfortably hot or even burned by either direct contact with the flames or by exposure to the radiant heat of the fire.

To demonstrate this hypothesis (with the habitable zones marked in green), Cueball is shown sitting outside the right habitable zone on the side of the fire. Even though he is able to toast his marshmallows on the fire due to his being close to it, he will have and is having part of his body scorched, as he is too close (fires can get really hot). Megan, also on the right, is well outside the habitable zone on the side away from the fire. Although not burned, the marshmallow on the stick she is waving will presumably not toast due to its being too far from the campfire. Ponytail, on the other hand, has found and is enjoying the medium between the plights of both Cueball and Megan by sitting entirely within her (the left) habitable zone, thereby both being close enough to the fire to be able to toast her marshmallows while also staying far enough away such that she will not be burned.

The title text introduces the concept of tidal locking, in which one astronomical body synchronizes its rotation with its orbit around another such that one side always faces the other body (e.g. the case of Earth's moon, which always presents the same face to the Earth). The joke here is that if a marshmallow became tidally locked to the fire, then one side would become more and more cooked, perhaps burnt, while the other side never became toasted at all. This also may allude to the instance in which a marshmallow has begun melting more than you realized and dripped down so far that it no longer responds to your rotation of the roasting stick (the solution to which is to cut your losses and pull the marshmallow out immediately, before it drops into the fire pit).


[A campfire is in the middle of the panel in a white area with two areas shaded green to the left and right of the fire. There are also two white areas outside of these green areas. Ponytail is sitting normally on the ground to the left of the fire, with her body fully inside the left green area. She is facing the fire and is holding a stick in both hands. The stick has a marshmallow on the tip and she is holding it over the top of the flames of the fire. Cueball is sitting to the right near the fire, only half inside the green are. He is sitting sideways leaning away from the fire, holding one hand to his head, while his other hand seems to be ready to support him as he is leaning further away from the fire. The arm closest to the fire and his head seems to be very hot as three small smoke-like lines rises from Cueball. Megan is crouching to the right of Cueball, far from the fire outside the right green area. She is supporting herself on one knee and one foot. She is also holding a stick in both hands with a marshmallow on it. She is holding the stick inside the green area to the right of Cueball far from the fire. Four small lines above and below indicates that she is waving the stick up and down. The camp fire is built up of several logs on top of each other, with big flames above it, with smaller flames hanging loose in the air above the main flames. A small dead tree is to the far left and small rocks/stones lie along the ground all the way from left to right interspersed with grass tufts. Below the scene there is a label from which two curved arrows point to the two green areas.]
Label: Habitable zone
[Caption below panel:]
Astronomers define the Campfire Habitable Zone as the region where you're far enough not to be burned but close enough to roast marshmallows.

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Amazingly how similar my aborted (edit-conflicted) edit matched what I found had gazumped me within the prior few minutes. Almost paragraph-for-paragraph on the same topic, with very similar details. Great minds think alike! (Fools never differ...) 01:58, 23 July 2020 (UTC)

Same thing happened to me. This was my first time trying to submit the main explanation. Barmar (talk) 02:11, 23 July 2020 (UTC)

Since the marshmallow's axis of rotation (i.e. the stick) is parallel rather than perpendicular to its orbital plane, it cannot be tidally locked in terms of its rotation. However, for the same reason, one side of the marshmallow, that which is closest to the end of the stick, does always face the campfire. 02:43, 23 July 2020 (UTC)

Take note of how Ponytail is toasting the Marshmallow above the fire with the stick nearly horizontal. In this orientation, the marshmallow typically becomes too gooey inside to maintain traction on a skewer or smooth stick. Rotating the skewer/stick becomes futile as the marshmallow spins relative to the skewer/stick but remains in the same direction relative to the fire, which will be with the heaviest part down due to the earth's gravity. In maintaining the analogy, the more massive side of the marshmallow is attracted to the fire... it has become tidally locked and cannot escape, preventing even toasting of the marshmallow. Dodgo (talk) 04:14, 23 July 2020 (UTC)

you cannot toast marshmallows on a single tip skewer, you need to use a marshmallow fork (which for linguistic reasons that escape me is called a fork despite having only two prongs). Care still must be exercised that the insides don’t become so gooey that the marshmallow falls off, but with a fork you can rotate and brown all sides evenly. 04:20, 23 July 2020 (UTC)
(A fork in the road has only two 'tines', or is liable to puncture a tyre if it was just a joke set-up. Four-pronged forks for general dining only became common in the early 1800s, and all kinds of contemporary forks, for given purposes, have three or two tines. The earliest forks were indeed just two-forked, as they do the basic job of doubly-impaling, whereas modern ones have to partly act as 'shovel', or even 'rake', so need more prongs. Though rarely >4.) 12:01, 23 July 2020 (UTC)
Tuning forks also only have two tines. 12:02, 24 July 2020 (UTC)

How long a stick would we need to roast marshmallows with the sun? Probably not Douglas Hofstadter (talk) 06:25, 23 July 2020 (UTC)

Don't know about marshmallows, but from a recent radio show (first item) I learnt that a (cylindrical, so marshmallow-shaped) burrito should be placed 60 million km sunwards. Assuming "no additional equipment", but plenty of other caveats. No discussion of how you get your snack back to you while still only cooked and before it cools down. Obviously marshmallows (on sticks, solving one issue) are a different prospect, but maybe start with that and experiment a few times? 12:23, 23 July 2020 (UTC)
Maybe this question could revive "What If?" and in addition to tackling "roasting" the marshmallow it could address how fast you'd have to retrieve it before it radiated away enough heat to no longer be "gooey" 12:30, 23 July 2020 (UTC)

Am I the only person thinking that Cueball left the habitable zone because Megan, trying to get her marshmallow to toast, has just poked him in the face with her stick? Angel (talk) 09:03, 23 July 2020 (UTC)

According to my research, not all campfires possess a habitable zone. A few are too small to roast marshmallows; some are large enough that you cannot comfortably stand within marshmallow-roasting distance; and others just had some of that colored-fire gunk thrown in them and you don't want to roast food over whatever that gives off. GreatWyrmGold (talk) 13:39, 23 July 2020 (UTC)

I doubt that. Since you can roast a marshmallow on a candle flame just fine I can't imagine a campfire(!) being too small for that. And as for the problem with too big fires it all depends on the length of the stick you are using. But again, we are talking about campfires - these are generally meant to be used for cooking. If you want to actually eat that marshmallow is indeed dependent on the stuff you are burning, on that I agree. Elektrizikekswerk (talk) 13:54, 23 July 2020 (UTC)

I've found that the habitable zone can get compromised by the smoke direction. 16:32, 23 July 2020 (UTC)

Is it too far fetched to think that "Campfire habitable zone" is a much more direct 1:1 reference on the term "Circumstellar habitable zone". According to the Wikipedia article the first scientific definition of habitable zone from Dole (1964) was the range of 0.72 A.U. to 1.24 A.U. If the same horizontal scaling is applied to the green zones in the comic, then the position of Ponytail pretty precisely corresponds to the distance of planet Earth, the position of Cueball pretty precisely corresponds to the position of Planet Venus and Meghans position quite well corresponds to the position of Planet Mars? Farnsworth (talk) 20:12, 23 July 2020 (UTC)

-- I think it's rather related to this https://www.sciencemag.org/news/2020/07/solar-images-reveal-campfires-sun 16:25, 27 July 2020 (UTC)

Please note: There may be a misspelling in this panel. See the claimed distinction between "marshmallow" (in the panel) and "marshmallow." https://www.askdifference.com/marshmellow-vs-marshmallow/ JDAddelston (talk) 14:36, 24 July 2020 (UTC) JDAddelston

I have looked at the current page, the image, and some way back in page history, and I only see "marshmellow" (noted within as incorrect) in that URL you give. Maybe I have missed the point, or it has changed without my noticing, in which case maybe you perhaps should clarify. (I also noted, while checking this, that one historic edit was for a couple of "-ise"->"-ize" changes. But I could point out other changes where international/anglicised usages could be americanized, if this is at all important.) 19:47, 24 July 2020 (UTC)

Can we delete the incomplete tag now? I think we have explained everything.--Some user (talk) 00:25, 26 July 2020 (UTC)

Some amateurish Googling indicates that the more craters on the far side of the moon are not because it’s tidally locked, but because volcanoes on the near side obliterated many. I’m removing the “as a consequence, the far side of the moon has many more craters caused by impacts“ assertion, but noting it here in case I’m wrong ... Miamiclay (talk) 14:57, 26 July 2020 (UTC) 14:49, 26 July 2020 (UTC)

Why does it say that the lines beside Megan's stick indicate that she is waving it? Surely they just mean she is shivering? 14:59, 12 September 2020 (UTC)

Why would only the stick be shivering, and not Megan herself? Nitpicking (talk) 10:41, 1 November 2023 (UTC)