Timeline for Can a large hemispherical planet be stable? [duplicate]
Current License: CC BY-SA 4.0
27 events
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| Sep 26, 2019 at 15:22 | vote | accept | A Lambent Eye | ||
| May 16, 2019 at 22:13 | comment | added | Escaped dental patient. | @HDE226868 I think I get it. Complex, not entirely transparent system behavior, a bit like life then. ;-) | |
| May 16, 2019 at 22:09 | comment | added | HDE 226868♦ | @Hoyle'sghost No comments were deleted by mods; comments made through the close vote interface ("Possible duplicate of [X]") are automatically deleted by the system after the question is closed. | |
| May 16, 2019 at 21:14 | history | closed |
Gary Walker Morris The Cat Cyn Escaped dental patient. Dewi Morgan |
Duplicate of What if the earth were physically split in half?, Could you build a non-spherical structure that's >1000km long? [closed] | |
| May 16, 2019 at 21:12 | comment | added | Dewi Morgan | Also slightly related: worldbuilding.stackexchange.com/questions/56563/… | |
| May 16, 2019 at 21:10 | comment | added | Dewi Morgan | The short answer is "there are no other possibilities over the Potato radius": arxiv.org/pdf/1004.1091.pdf - a longer answer would have to include deliberately constructed objects. | |
| May 16, 2019 at 20:26 | history | edited | A Lambent Eye | CC BY-SA 4.0 |
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| May 16, 2019 at 20:16 | comment | added | RBarryYoung | All “large” bodies effectively act like liquids, that is they are 99% shaped by gravity (and momentum). They are NOT shaped by their internal static structure the way that smaller everyday solids are. The boundary between these behaviors is a radius of around 200 miles, IIRC. | |
| May 16, 2019 at 20:13 | history | became hot network question | |||
| May 16, 2019 at 20:12 | comment | added | JBH | Oh, and just because it sounds like fun, was the Earth or Earth-like planet having a similar lunar setup sliced longitudinally? In which case the half separating the fastest would eventually have to pass through the lunar orbit (bang!) or equatorially? In which case the moon does something... interesting.... | |
| May 16, 2019 at 20:11 | comment | added | JBH | What do you mean by stable? Would Earth, if this happened, be stable enough for life? Would its orbit be stable? Its rotation? Would the moon also need to be stable? Are you asking about two days later, when the other half is still nearby, or 10K years later, when the system has "restabilized" because it's original "stability" was disrupted by a celestial butter knife? What do you mean by "stable?" | |
| May 16, 2019 at 19:24 | history | edited | A Lambent Eye | CC BY-SA 4.0 |
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| May 16, 2019 at 19:15 | comment | added | A Lambent Eye | @GaryWalker A good find! I suppose it answers the question for an earth-sized planet, but I'd find it interesting to learn about other possibilities. | |
| May 16, 2019 at 19:10 | comment | added | notovny | A simple slice won't separate them, either. Cut Earth in half, and the two halves will smack back together. You'll need to do something to put some significant relative velocity ( at least enough lateral velocity to put them in orbit round each other) between the two halves and do it gently enough that your halves aren't torn to pieces by the acceleration. | |
| May 16, 2019 at 19:10 | review | Close votes | |||
| May 16, 2019 at 21:14 | |||||
| May 16, 2019 at 18:50 | comment | added | Theraot | Related: Could you build a non-spherical structure that's >1000km long? | |
| May 16, 2019 at 18:45 | comment | added | Starfish Prime | @MorrisTheCat "immediate collapse into smaller spheres" seems slightly dubious, except for geological meanings of "immediate",. That said, I wouldn't want to be anywhere near the cut edge. | |
| May 16, 2019 at 18:38 | comment | added | A Lambent Eye | @MorrisTheCat I am not ignoring it, I am uninformed concerning it, which is why I write these ignorant questions. Do feel free to write an answer and elaborate on it as much as you'd like. I will be thankful. | |
| May 16, 2019 at 18:37 | comment | added | Morris The Cat | @ALambentEye you're ignoring a whole bunch of physics here, mostly around gravity. It's not the earth's spin that keeps it from collapsing, it's the mass of the stuff underneath it being in hydrostatic equilibrium. Cutting the planet neatly in half removes that, and both halves would immediately collapse into smaller spheres. The only way this would work is if you're starting with something much smaller than we normally think of as a planet. The only astronomical bodies that are able to remain stable in a non-spherical shape are things less than ~50km across. | |
| May 16, 2019 at 18:36 | history | edited | A Lambent Eye | CC BY-SA 4.0 |
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| May 16, 2019 at 18:33 | comment | added | A Lambent Eye | @knowads I imagine a planet living a happy life when one day it is simply split in half and each half drifts away. According to my understanding of gravity, there are now two centers of gravity and each rotates faster now that there is less mass. Is that right? It certainly isn't a gas giant, but it might have a small atmosphere. | |
| May 16, 2019 at 18:14 | answer | added | Mathaddict | timeline score: 4 | |
| May 16, 2019 at 17:25 | history | edited | HDE 226868♦ | CC BY-SA 4.0 |
Edited title and tags.
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| May 16, 2019 at 17:13 | answer | added | HDE 226868♦ | timeline score: 13 | |
| May 16, 2019 at 17:09 | answer | added | L.Dutch♦ | timeline score: 1 | |
| May 16, 2019 at 16:51 | comment | added | knowads | Is this planet literally sliced in half? What is the gravitational center of this new body - is it the point from the old planet? Does it still rotate about the same axis? Does it have an atmosphere? | |
| May 16, 2019 at 16:44 | history | asked | A Lambent Eye | CC BY-SA 4.0 |