Difference between revisions of "3136: Pull"
(We need to work on formalizing language.) |
|||
| (5 intermediate revisions by 4 users not shown) | |||
| Line 10: | Line 10: | ||
==Explanation== | ==Explanation== | ||
| − | [[Megan]] and [[Cueball]] are lying in the grass on an orb – | + | [[Megan]] and [[Cueball]] are lying in the grass on an orb – possibly a stylized Earth, though the large amount of curvature suggests a much smaller body. However, instead of the conventional frame orientation where gravity points towards the bottom of the image, the viewpoint is stationary outside the body while we see it slowly rotating, reminiscent of the alternate frame of reference apparently in use in [[2800: Down]]. Shown this way, we may have the intuitive feeling that the protagonists should fall off, and this makes a point how abstract gravity seems to be when it is carefully thought through, continuing with the theme of abstract reality seen in the previous comic, [[3135: Sea Level]]. |
| − | In the first panel, Cueball expresses that he doesn't like being stuck there, possibly because he wants to explore other worlds or because he finds Earth limiting. The alternative would be | + | In the first panel, Cueball expresses that he doesn't like being stuck there, possibly because he wants to explore other worlds or because he finds Earth limiting. The alternative would be "falling off", as in experiencing the {{w|Centrifugal force}} that results from the Earth's rotation – this would appear in the comic's perspective as both characters slowly "falling" away towards the right side of the panel. As this centrifugal effect is quite slight compared to the gravitational acceleration we're used to (0.34% of it at the equator), Megan and Cueball would have roughly three more minutes until they "fell" off-panel, assuming their position is of a mid-northern latitude typical to the US – unless they're able to fly under their own power now that they're no longer constrained by gravity, or unless the rest of Planet Earth also has its gravity turned off and violently explodes as a result. |
| − | In the second panel, Megan uses a more metaphorical sense of the word pull, she is attracted to lying on the grass doing nothing and blames her inability to get up and do things | + | In the second panel, Megan uses a more metaphorical sense of the word pull, she is attracted to lying on the grass doing nothing and blames her inability to get up and do things on gravity, using the topic of conversation as a punchline for a joke. This could also mean that if the pull (aka gravity) is less, she could get up more easily and get to where she wants to go. |
| − | Cueball replies that the pull might weaken over time. In a literal | + | Cueball replies that the pull might weaken over time. In a literal sense, gravity will not decrease significantly even in the long term and is likely not an actual obstacle to Megan getting up{{cn}}. [https://www.cbc.ca/radio/quirks/sept-1-2018-gene-editing-in-dogs-wildfire-prediction-zika-fizzles-and-more-1.4804892/is-earth-getting-heavier-or-lighter-1.4804900 Earth gains mass] from dust and meteorites but also loses mass, mainly due to escaping hydrogen and helium. The net effect of these is for Earth to lose about 50,000 tonnes per year; in the 5‑minute period Megan mentions, equivalent to 500 kg out of the Earth's mass of 5.972 × 10<sup>24</sup> kg, changing gravity by a factor of about 10<sup>-22</sup> (1 part in 10 sextillion). Locally, gravity can also change due to mass redistribution. The Earth's core is very slowly cooling, leading to decreasing radius and thus increasing gravity at the surface. Towards the end of its life, the Earth's water will be boiled off due to the expanding Sun, leading to a decrease in gravity. Metaphorically, Cueball seems to just be saying that so she will stay a bit longer. Megan agrees. |
| − | Fighting the gravity in the title text is reminiscent of the Ancient Greek story of {{w|Icarus}}, who fell down after flying too close to the Sun, where flying might be seen as fighting gravity. It might also just be a rephrasing of the truism "The higher you go, the longer the fall". On the other hand, "it's a long way down" may not refer | + | Fighting the gravity in the title text is reminiscent of the Ancient Greek story of {{w|Icarus}}, who fell down after flying too close to the Sun, where flying might be seen as fighting gravity. It might also just be a rephrasing of the truism "The higher you go, the longer the fall". On the other hand, "it's a long way down" may not refer to falling back to Earth, but rather falling off the Earth, if one were no longer "stuck" to it. In that case, "down" would presumably mean toward the Sun, the center of gravitational pull in the solar system – a very long way away. If one "defeated" ''all'' gravity, "down" would mean "away from the Earth into space" endlessly, unless one happened to collide with some object. |
| − | However, you could avoid this if you had a method of self-propulsion, which brings to mind Superman, who is a good example. He can "defeat" gravity and has some method of self-propulsion (which is, obviously, how he | + | However, you could avoid this if you had a method of self-propulsion, which brings to mind Superman, who is a good example. He can "defeat" gravity and has some method of self-propulsion (which is, obviously, how he flies). While humans don't have any natural means of self-propulsion while in a gravity free environment{{cn}}, they can use artificial methods (eg a jetpack). |
==Transcript== | ==Transcript== | ||
| Line 27: | Line 27: | ||
:Cueball: but I guess falling off would be worse. | :Cueball: but I guess falling off would be worse. | ||
| − | :[Cueball, Megan, and the surface are now rotated a little | + | :[Cueball, Megan, and the surface are now rotated a little bit from the first panel.] |
| − | :Megan: I wouldn't mind if it pulled a little less | + | :Megan: I wouldn't mind if it pulled a little less hard, though. |
:Megan: I have places to be. | :Megan: I have places to be. | ||
:Megan: I shouldn't just lie around in the grass. | :Megan: I shouldn't just lie around in the grass. | ||
Latest revision as of 14:50, 9 October 2025
| Pull |
 Title text: Be careful fighting gravity. If you win, it's a long way down. |
Explanation[edit]
Megan and Cueball are lying in the grass on an orb – possibly a stylized Earth, though the large amount of curvature suggests a much smaller body. However, instead of the conventional frame orientation where gravity points towards the bottom of the image, the viewpoint is stationary outside the body while we see it slowly rotating, reminiscent of the alternate frame of reference apparently in use in 2800: Down. Shown this way, we may have the intuitive feeling that the protagonists should fall off, and this makes a point how abstract gravity seems to be when it is carefully thought through, continuing with the theme of abstract reality seen in the previous comic, 3135: Sea Level.
In the first panel, Cueball expresses that he doesn't like being stuck there, possibly because he wants to explore other worlds or because he finds Earth limiting. The alternative would be "falling off", as in experiencing the Centrifugal force that results from the Earth's rotation – this would appear in the comic's perspective as both characters slowly "falling" away towards the right side of the panel. As this centrifugal effect is quite slight compared to the gravitational acceleration we're used to (0.34% of it at the equator), Megan and Cueball would have roughly three more minutes until they "fell" off-panel, assuming their position is of a mid-northern latitude typical to the US – unless they're able to fly under their own power now that they're no longer constrained by gravity, or unless the rest of Planet Earth also has its gravity turned off and violently explodes as a result.
In the second panel, Megan uses a more metaphorical sense of the word pull, she is attracted to lying on the grass doing nothing and blames her inability to get up and do things on gravity, using the topic of conversation as a punchline for a joke. This could also mean that if the pull (aka gravity) is less, she could get up more easily and get to where she wants to go.
Cueball replies that the pull might weaken over time. In a literal sense, gravity will not decrease significantly even in the long term and is likely not an actual obstacle to Megan getting up[citation needed]. Earth gains mass from dust and meteorites but also loses mass, mainly due to escaping hydrogen and helium. The net effect of these is for Earth to lose about 50,000 tonnes per year; in the 5‑minute period Megan mentions, equivalent to 500 kg out of the Earth's mass of 5.972 × 1024 kg, changing gravity by a factor of about 10-22 (1 part in 10 sextillion). Locally, gravity can also change due to mass redistribution. The Earth's core is very slowly cooling, leading to decreasing radius and thus increasing gravity at the surface. Towards the end of its life, the Earth's water will be boiled off due to the expanding Sun, leading to a decrease in gravity. Metaphorically, Cueball seems to just be saying that so she will stay a bit longer. Megan agrees.
Fighting the gravity in the title text is reminiscent of the Ancient Greek story of Icarus, who fell down after flying too close to the Sun, where flying might be seen as fighting gravity. It might also just be a rephrasing of the truism "The higher you go, the longer the fall". On the other hand, "it's a long way down" may not refer to falling back to Earth, but rather falling off the Earth, if one were no longer "stuck" to it. In that case, "down" would presumably mean toward the Sun, the center of gravitational pull in the solar system – a very long way away. If one "defeated" all gravity, "down" would mean "away from the Earth into space" endlessly, unless one happened to collide with some object.
However, you could avoid this if you had a method of self-propulsion, which brings to mind Superman, who is a good example. He can "defeat" gravity and has some method of self-propulsion (which is, obviously, how he flies). While humans don't have any natural means of self-propulsion while in a gravity free environment[citation needed], they can use artificial methods (eg a jetpack).
Transcript[edit]
- [Cueball and Megan lying on a surface with grass, and the surface is round. They are orientated sideways, slightly facing up.]
- Cueball: I don't like being stuck to this orb,
- Cueball: but I guess falling off would be worse.
- [Cueball, Megan, and the surface are now rotated a little bit from the first panel.]
- Megan: I wouldn't mind if it pulled a little less hard, though.
- Megan: I have places to be.
- Megan: I shouldn't just lie around in the grass.
- [Cueball, Megan, and the surface are now rotated a little bit more from the second panel, slightly facing down.]
- Cueball: Maybe the pull will weaken if you wait around a little longer.
- Megan: Good idea. I'll give it another five minutes.
Add comment 
Create topic (use sparingly) 
Refresh Discussion
Australia reference????? /s TheTrainsKid (talk) 05:41, 2 September 2025 (UTC)
I recently learned that earth has weird gravity effects caused by a big moon orbiting near the surface. These are probably also barely measurable, except e.g., big bodies of water --134.102.219.31 11:23, 2 September 2025 (UTC)
- I take it you haven't heard of Earth tides? [1] --Gorcq (talk) 11:54, 2 September 2025 (UTC)
- Perhaps you should follow the link in the comment you replied to... Yorkshire Pudding (talk) 13:00, 2 September 2025 (UTC)
- It's a real effect. It has been proven by neutron interferometry. (https://en.wikipedia.org/wiki/Neutron_interferometer) -- Lordpishky (talk) 02:30, 3 September 2025 (please sign your comments with ~~~~)
- Perhaps you should follow the link in the comment you replied to... Yorkshire Pudding (talk) 13:00, 2 September 2025 (UTC)
- Ya the hemispheres are kinda crazy《プロキシ》(XKCD中毒者) 13:07, 2 September 2025 (UTC)
So I'm not qualified to critique this, but, I think the comic is referencing an unsolved problem - is gravity constant over time? I'm not a physicist and I'm not conversant with the literature, but I think there is some debate on the matter. The line 'give it another five minutes' definitely seems like a humorous reference to the idea that the gravitational constant might change over age-of-the-universe timescales. Hence I suspect the description talking about earth's attraction specifically misses the point. --DW 2607:FB90:8FA9:E54A:5856:AACD:B913:6DD8 13:44, 2 September 2025 (UTC)
Judging from the amount of rotation, the conversation takes place over a period of several hours. -2603:8080:2AF0:F1E0:39BF:23FC:411E:363B 18:58, 2 September 2025 (UTC)
Someting seams wrong with the number in the statement "The net effect of these is for Earth to lose about 520 tons in the 5-minute period". I found that "Each day, around 90 tonnes of hydrogen and helium escape from Earth in the direction of space" https://www.snf.ch/en/2QLt6mvuU4hZj1yx/news/leaking-atmospheres-seal-the-fate-of-planets Maofgf (talk) 19:10, 2 September 2025 (UTC)
It should be "centripetal", not "centrifugal". Inquirer (talk) 20:40, 2 September 2025 (UTC)
- Centrifugal force is correct here. Centripetal force is the force keeping an object on a circular trajectory (in a fixed reference frame), in this case it is gravity. In the rotating reference frame, the object is stationary, as centripetal and centrifugal force cancel each other out. As soon as gravity stops, there is no centripetal force anymore. In the rotating reference frame, the object accelerates outwards by the centrifugal force (on a curve due to the Coriolis force); on an fixed reference frame, there is no force and it travels in a straight line. 2A02:1210:82E7:3100:37D6:4369:7925:6854 22:01, 2 September 2025 (UTC)
I'm completely failing to understand the stuff about "roughly three more minutes until they "fell" off-panel". What's that based on? BunsenH (talk) 20:57, 2 September 2025 (UTC)
This is disturbingMathmaster (talk) 21:58, 2 September 2025 (UTC)
Is the centrifugal effect at the equator truly exactly 0.34% of the gravitational acceleration at the equator? That seems like an astonishing mathematical coincidence, to be a ratio that is an integer over a small power of ten! 47.150.86.14 05:45, 3 September 2025 (UTC)
Proof Earth is a Katamari. VonAether (talk) 13:47, 3 September 2025 (UTC)
It's a long way down only if you don't have a method of self-propulsion, like Superman!2600:100F:B1BF:AAD5:F118:400C:2C92:2C67 12:43, 14 September 2025 (UTC) Add comment
