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Background:

There is an alien civilization, many billions of light-years from Earth. This civilization hosts itself on a large rocky asteroid with an artificial atmosphere and artificial gravity. In the past, this rock had been separated into five, with one large in the middle, and the other four orbiting around it. These rocks have relatively flat faces that the aliens have built their cities.

Edits: Each rocky area would comprise of one main city with a limited area of wild-life, think New York City with a small forest right after it. This rocky area would not be formed as a disc, rather a shape much like unformed clay with a slightly rounded, but mostly flat face. (NOT like a cube or, again, disc. Think ball with one part with a smaller radius.) This rock face would have to form naturally. Please note that these are aliens that have evolved to live on this rock. Aliens are to this rock as we are to earth.

QUESTION:

So... odd question, but is it possible that an asteroid/planet could form with a 'flat' face, and if so, how would I explain how it was created, other than magic! Also, I don't mean perfectly flat, more along the lines of a low-incline dome. Finally, would it be possible for smaller pieces of it to orbit it, or would that break the whole 'flat' thing.

Well done picture: See if this helps. Sorry, I don't have any better drawing tools.

Note:

This is going so well for my first question on this site!

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closed as unclear what you're asking by Mołot, Aify, DonyorM, sphennings, L.Dutch May 9 '17 at 8:56

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Also, are you planning for there to be surface gravity on your flat faced asteroids? Or is that provided by some artificial means? How big are your five planetoids? $\endgroup$ – kingledion May 8 '17 at 19:51
  • $\begingroup$ There's a big difference between the mass of a planet and an asteroid. Could you be more specific about the scale of your object? $\endgroup$ – sphennings May 8 '17 at 19:55
  • $\begingroup$ @kingledion known / observable does not mean there is nothing outside it. it only means we'll never see it. Probably. Not a problem when we are talking fiction. $\endgroup$ – Mołot May 8 '17 at 20:04
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    $\begingroup$ If there's artificial gravity you've already wiggled your fingers and said "magic". $\endgroup$ – sphennings May 8 '17 at 20:11
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    $\begingroup$ Possible duplicate of How can I prevent a cube world from going spherical $\endgroup$ – Aify May 8 '17 at 20:36
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It is possible to manufacture them, but there is not much point. You can melt down asteroids and make whatever shape you want, assuming it was not big enough to collapse under its own gravity in the first place. You get better use out of the material by building spheres or cylinders, plus they are a lot easier to make, and flat is only useful if you're organisms do not need gravity but still wants a flat surface (so nothing like multicellular life on earth) or you have cheap reliable artificial gravity. The only real reason to make them is showing off.

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    $\begingroup$ Actually showing off is a reason I would believe in. $\endgroup$ – Mołot May 8 '17 at 21:53
  • $\begingroup$ Thanks dude! I think I will likely have to re-write the whole thing, or just put in some hidden cheesy comment about it being "showing off". It's really supposed to be like the main space city in "Treasure Planet", but more like a rocky platform. $\endgroup$ – The Lord Char May 8 '17 at 22:48
  • $\begingroup$ @TheLordChar does your flat planet spin? If it does, then -- even with artificial gravity -- "stuff" will get hurled to the edges due to (yes, yes, ficticious) centrifugal force. $\endgroup$ – RonJohn May 8 '17 at 23:54
  • $\begingroup$ depending on how fast it spins. $\endgroup$ – John May 10 '17 at 0:45
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    $\begingroup$ @TheLordChar Physics is a bitch, isn't it? :) All these cool ideas, and every one of them have some "no fun" impact on your story... :( $\endgroup$ – RonJohn May 10 '17 at 1:29
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If you have asteroid/planet-sized Artificial Gravity, presumably you can use it to create a world that is any shape you want. At large scales, solid materials just follow the gravitational topography, so you'd just have to shape the gravity to control/shape the large-scale structure of your world.

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Sure, you could have an asteroid that was impacted by something in the past and fractured to have a flattish surface, fossil hunters do this fairly regularly when they hit rocks with hammers.

If your asteroid has a crystalline structure even easier to do.

A flattish surface is no less unlikely that Saturns moon Pan which as you can see from the NASA picture below looks like a classic UFO flying Saucer which has been continually covered with dust and ice for millenia (which it actually might be).

Pan

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  • $\begingroup$ The problem with this is that Pan was formed that way due to its gravity attracting particles from Saturn's rings to form the disk so it would have to be in a ring system. This also limits how big it can get because at one point the gravity of the planet it's orbiting will take away the particles it attracts. $\endgroup$ – Cameron Leary May 9 '17 at 20:54
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    $\begingroup$ @CameronLeary until it has been physically cracked open and proven that there is no derelict Flying Saucer inside I'm sticking with my theory of a stranded alien space ship covered in millions of years of dust and ice. $\endgroup$ – Kilisi May 9 '17 at 21:37
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    $\begingroup$ Don't forget the super secret alien rescue mission (some call it the Cassini probe but we all know that's not true) $\endgroup$ – Cameron Leary May 9 '17 at 21:43
  • $\begingroup$ Actually, that's perfect! I would still like to have some reasoning that it would form naturally. $\endgroup$ – The Lord Char May 10 '17 at 1:10
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Flat planets can't be created, because gravity pulls all the bits of the planet "in", and a sphere has the lowest mass-area ratio. (Rotation flattens them out a little, but not much.)

Asteroids are aggregated clumps of rock/stone that don't have enough mass to make gravity pull it into a sphere. That's why they're all lumpy and misshapen. But none are flat.

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