RW-sized planets in our universe: what would they be like

[Dive]

So yesterday I've got a random shower thought: "Hey, while starting a colony in Rimworld you are free to choose the size of the planet's map, as well as the size of a cell on the map! I wonder how big of a planet you can generate!". As no shower thoughts shall be ignored and being a huge "What if" and XKCD fan, I've decided to dive into a small research to figure out what would it be like to actually have a Rimworld in our universe.

So, I thought it's a good idea to pick three different setups:
1) The smallest setup: 150x112 world map, a cell is 200x200 tiles.
2) The standart setup: 200x150 world map, a cell is 250x250 tiles.
3) The biggest setup: 400x300 world map, a cell is 400x400 tiles.

Next, i had to make a couple of assumptions:
1) A single tile on the game map is 1x1 m
2) The world map generated in game is only a half of the planet, either northern or southern.

Given that information it's not all that hard to figure out the planet's circumference. I just multiplied a cell's vertical size by the amount of cells the world map fitts in any vertical column, and then multiplied it by 4 to get the full circle, and knowing the circumference it's easy to figure out planet's radius. So that's what radius I've got:
1) The smallest: 14.2 km
2) The standart: 23.9 km
3) The biggest: 76.4 km
Knowing that I made a picture comparing these Rimworlds to our planet's only natural satelite:



Ok that's what a RW in the sky would look like. Kinda tiny, yeah.
That's it.



....or is it? I wouldn't be a "What-if" fan if I didn't get into that hypothetical situation a little bit more. What would it feel like to stand on a rimworld's surface?
Well first of all, the horizon would be closer. MUCH closer. A person of average height standing on the sea level sees Earth's horizon at ~4.9 km, compare that to the rimworlds.
1) On the smallest RW the horizon is at 570m.
2) On the standart - 735 m.
3) On the biggest - 1315 m.
Before I made the calculation I thought I wouldn't be surprised if the sniper rifle range is limited by the planet's surface bending down and hiding enemies below the horizon, but apparently I was underestimating the planet's size. But still, the horizon at 570 m would feel frighteningly close, you would probably feel kinda claustrophobic.

Now let's get into weird stuff, but first we need to make a few more assumptions:
3) People on the surface of a rimworld experience the same amount of free-fall acceleration as we do on Earth (~10 m/s^2)
4) The gravity constant is the same in RW universe
How do you experience the same gravity on a body that is much smaller than Earth? Well, the body should be massive. We know how big each planet is so we can calculate mass that a planet should have to produce enough gravity, it's respectively
1) 1.2*10^21 kg
2) 3.4*10^21 kg
3) 34.5*10^21 kg
That's a lot, but Earth is three orders of magnitude heavier, so still not really much. But if we divide the mass of a planet by it's volume we get that..

A spoon of the smallest rimworld weights almost 2 kilograms.

To be more specific, these densities I've got for all the planets:
1)Smallest 399 666 kg/m^3
2)Standart 238 734 kg/m^3
3)Biggest 74 604 kg/m^3

If rock chunks on a rimworld are made from the same material as the planet itself then it kinda surprises that they can be carried by a single person, because they probably weigh a few hundred tons
I think now we know enough.
Would you live on such a world? =)

PS Ok here is the last small bit of information for you. A trading ship orbiting rimworld 10km above the surface would be moving at
1) Smallest 898 m/s
2) Standart 1186 m/s
3) Biggest 2168 m/s

[attachment deleted due to age]

[Coenmcj]

What if it isn't the standard amount of gravity that we all know, being 9.8 Metres per sec per sec?
It most likely still follows the gravity constant, but what if it's something lower than the ~10, considering the planet's tiny sizes, something like ~6 or ~5 or lower?
It would certainly explain how they can carry some of the heavier objects with apparent ease, Like the mechanoids or rock chunks.

[milon]

Who says it must be of uniform density?  Wil McCarthy's Queendom of Sol series addresses the idea of compressed-core few-km celestial bodies with Earth-like gravity.  (Good series by the way, especially book 2.)

Also, moved to Off Topic. 

[Dive]

What if it isn't the standard amount of gravity that we all know, being 9.8 Metres per sec per sec?
It most likely still follows the gravity constant, but what if it's something lower than the ~10, considering the planet's tiny sizes, something like ~6 or ~5 or lower?
It would certainly explain how they can carry some of the heavier objects with apparent ease, Like the mechanoids or rock chunks.

That would not change much, a spoon of the smallest rimworld would weight 1kg instead of 2kg and that's still a lot.

Who says it must be of uniform density?  Wil McCarthy's Queendom of Sol series addresses the idea of compressed-core few-km celestial bodies with Earth-like gravity.

Maybe, but imagine the density of the cores, it would be even higher

[milon]

Exactly. Compressed cores with normal-density outer layers. The gravity would feel the same, but you'd still have to deal with the freaky horizon issues.

And if that's true, it means that rim worlds are manufactured.  Which, in the RimWorld universe, means that a transcendent world had something to do with it.  Dun dun DUN!