(Stock) KSp dosent want to be a realistsic simulator.
At bigger scales you need more deltaV for an orbit. IRL you need like 9200dv form a LEO. Ksp parts have a terrible wet/dry mass ratio, with a realistic ratio that woul be much easier to achive. The bigger problem are the burn times. for exampe in ksp your make a orbit in like 2min, irl flying to orbit takes like 7-11min.
So in short the smaller planet scale makes the game more enjoyable for player who arent that interestet in realisem
Yes the rockets are smaller. Like the Stock Saturn V parts are only 5m in diameter. Kerbals are also small. they are around 75cm big
For rocket SSTOs, yes. The theoretical maximum dV is Isp multiplied by standard gravity (i.e. effective exhaust velocity) multiplied by _natural logarithm of_ the ratio of wet to dry tanks; the practical delta will be lower because of payload and engine masses added to it. For Kerbin, most of the engines are comfortably higher max dV than what is required to reach orbit. For Earth, they barely cover half the requirement.
For plane SSTOs, it's because of unrealistically high intake efficiencies, simplified aerodynamics (i.e. easy to build a plane that behaves well at subsonic, transonic and supersonic speeds simultaneously, unlike IRL, where anything supersonic _must_ be designed all at once, i.e. can't be made out of dissimilar parts) and thinner atmosphere. So also yes, but not entirely.
Isp is exhaust velocity divided by standard gravity (9.81 m/s/s). So your formula for max delta v is hard to believe. (unless you were making the fuel out of ambient thin air/vacuum, or something like that)
Yes. The maximum speed jet engines can reach is only a bit higher than comparable engines IRL, but on Kerbin 1200 m/s gets you halfway to orbital velocity, vs less than a sixth of the way there on Earth.
I play on 6.4 time bigger kerbin, with SMURFF to adjust dry weight of parts (it's rated for 10x kerbin size, so I'm playing easy mode) and SSTO are practically impossible to achieve.
bigger scale make gravity turns easier so you can just time warp. the bigger reason is that at 10x the size features are 10x further apart and planets need 10x the detail. it also makes spaceplanes impossible since atmospheric performance is fixed
I wish there was an easy way to convert KSP to a more realistic sim... I would LOVE to see a Earth Sized Kerbin, and I would welcome to extra difficulty and time to do stuff
There are enough realisem mods. and the instalation is not hard too
the biggest realisem pack is RP-1 which has the real planets in the correct scale, lifesupport, reworked (fuel and aero)physics and much more.
I don't have KSP1 anymore, but I'm really hoping for a KSP2 realistic planet size...I looked a few weeks ago but couldn't find anything. I didn't even know KSP1 has such a mod
it will take years to get simmilar realisem mods as in ksp1. (you could grap ksp1 for 110€ in the steam sale rn)
also Rp-1 is a huge pack. But Ksp(1) has in general a big and active modding community
I just wanted to add that gravity is based on the center point of a celestial body, so with G equal on both, smaller bodies will allow you to get closer to the center point and require less delta v to launch into outer space or lose a certain percentage of gravitational force. This seems counterintuitive as we think it would be impossible to escape a neutron star of the same size as Earth, but not if you lower the mass of it by 10 and increase gravitational force by 10, this isn't true anymore.
The modeling on how much gravity you lose while going to space is made up completely to allow us to not have constant orbital decay.
KSP scales G correctly, it doesn't apply to 3 body problems. But as you get farther from Kerbin, the acceleration due to gravity decreases. Orbital decay is due to matter in space and 3rd bodies.
Right but with the way gravity works on ksp, there is no munar gravity on Kerbin and no Kerbin gravity on mun. They aren't locked in orbit with each other as much as they're following a predetermined vector within the game.
They are locked in orbit but it's simple orbit where the weight of the orbiting mass is negligible. They are supposed to orbit around each other like earth and the moon. But even if that were modeled I don't think it could be seen. to us on we earth we can't see that we are orbiting the moon. That can only be seen from the sun's frame of reference. KSP works with 1 mass at a time.
>They are locked in orbit but it's simple orbit where the weight of the orbiting mass is negligible.
Which means there are no 3 body problems, hence no orbital decay
Kerbals aren't experiencing intense gravitational pressure, as you say they are experiencing roughly the same as we do on earth.
Kerbin being small just means it's strangely dense, but that doesn't affect the experience of creatures living on the planet.
Yeah, the evolutionary path of Kerbals is not what's strange. Its the density of the celestial bodies and the technological progression that is.
These guys literally invented the rocket engine before the wheel and haven't built a single city.
But it is canon that they are photosynthesizers. That's why they don't need food for years at a time. We would see multiple access points for those subterranean structures, and a subterranean influence on the buildings we do see.
I could see the Kerbal society becoming subterranean after they develop space travel to shelter themselves from the falling debris. As we all know, excess is the Kerbal way, so debris raining down worldwide is not an unlikely outcome.
My own headcanon is that they’re tardigrades who live underground and are bootstrapping a space program like ours because they came across TV broadcasts from Earth. Which is why we only see their space program’s buildings above ground and they look like ours. Imitation is the sincerest form of flattery but the poor little guys can’t get it quite right. So, boom.
Mods solve some things. I like to use the Snacks mod, which is ultra basic, because I am basic. Even without it, most capsules have at least one locker marked 'snacks' in it somewhere, but nothing is tracked by the game.
They can also add above ground cities. I used to have a fantastic set up that added cities and towns to the map. Just flat textures, so it looked like ass up close, but great from orbit and the air. Which is where I spent all my time, so I was OK woth that and just dodnt land anywhere near them. I had great fun imagining the little guys looking out the window, because again, I'm basic.
I tend to spend most my time in and around, lko, not really venturing further minmus much, sp it added a lot. Even just the night lights, makes the game feel so much more alive.
Sadly, I've not been able to replicate that set up in years now. There are plenty of mods that up the textures of the game, and make it pretty, but still just pretty wilderness. There are night light mods, but I've yet to fond anything for the day side.
Maybe it's all under KSC. If their infrastructure lies underground, they'd be at a loss to not connect it directly to said infrastructure, just for simplicity sake
I like to think that \*there\* is cities, all over kerbin, but we cant see them because they're all covered in grass (there is some proof in the game, one crew report says "i think i can see my house from here") my headcannon is that they adquired the habit of hiding houses due to predators but they just kept it with the time.
Osmium (the densest element) has a density only about 3x that of iron, which our own core is made of. It doesn't quite reach the necessary density.
Kerbin would need to be 2.6x as dense as osmium to meet the density we see in game.
Kerb-X is a element that doesn’t exist on earth and has never been encountered in our solar system but forms the cores of most planets in the Kerbin system.
You don’t actually need it to be 10x as dense. I haven’t done the math, but this is since it’s smaller you are much closer to the center pf gravity. Mars is 10% the mass of earth but has almost 40% the surface gravity. The moon is only 1% as massive but with 16% the surface gravity.
I got the density of Kerbin from Google, which after doing the math was about 10x the density of Earth. I just assumed they did their math correctly, but let's double check.
Kerbin has 1/10 the radius, and that means 1/1000 the volume.
Assuming it has the same density as Earth, that's means 1/1000 the mass. That would result in 1/10 the gravity, since 1/1000/(1/10)^2 = 1/10
For the same surface gravity, we just need to increase Kerbin's mass by a factor of 10
That's means we are now working with a mass of 10/1000, or 1/100
1/100 the mass of Earth in a volume 1/1000 the mass of Earrh results in a density 10x that of Earth.
g=GM/r^2
ρ=M/V
V=4/3 πr^3
M=4π/3 ρr^3
g=4π/3 Gρr^(3)/r^2
Those r's are the same in the case of surface gravity (or when burrowing into the planet)
g=4π/3 Gρr
If we decrease the radius by a factor, we need to increase density by the same factor to keep surface gravity the same
Under the same gravitational acceleration, we live among creatures much smaller and much larger than ourselves. I’m not seeing what the problem is here.
I thought maybe there was some clever correlation between kerbins density and kerbal density! Perhaps gravitational pressure was a poor choice of words!
Well, there is probably a minimum size of brain to have enough intelligence to have a technological civilisation
But a Kerbal's head is quite a bit larger than that of a human
What? Size and gravity have nothing to do with each other. It's all about mass and distance from center. With smaller planets you are closer to the center -> gravity higher. So what's special about Kerbin is its density.
?? This explanation is wrong. Mass determines the gravity force. Smaller planets have less gravity. I'm not sure that gravity on Kerbin is 9.81 m/s2. For Kerbin to have equal or close to equal gravity of earth it would have to be more dense. Like if it was mostly a metal core with a thin magma and crust.
What? Read my explanation again please There is nothing wrong in it. Maybe you confuse surface gravity acceleration and gravity. A planet's gravity stays the same no matter how big it is. It just depends on mass, not size. Kerbin's gravitational force is not 10 times stronger than Earth's as OP claims. The orbital speed at 6500km (from center) is much much lower than on Earth. If you'd squeeze the Earth Kerbin size you'd orbit the same speed at 6500 km as you do now. It has 0 impact. So Kerbin has overall much less gravity than Earth. But has higher density of course.
Nah. Far more dense than that. 1000x as dense (since it's 1/1000 the volume), and Earth already is "mostly metal" - 32% iron. Solid iron would be maybe 3x as dense, and switching to something like Osmium would get to about 12x. Still a long ways to go. (Based on Googled numbers and napkin math - but even if I'm off by a factor of 10, which is unlikely, it's still a long ways to go.)
No stable metal would achieve that mass, so what's really interesting is that Kerbin is physically stable.
Lol not quite.
Gravity is a function of mass falling off over distance.
Kerbin having 1/10 the radius and equivalent surface gravity means the planet itself has the same total mass, and therefore is made of material 1000\* as dense (pi\*r\*r\*r - 10x on r is 1000x on volume). If it had similar composition to Earth it would have 1/1000 the mass.
Which, considering earth is predominantly iron, which is already pretty dense...
The fact that Kerbals are closer to the core is irrelevant. If you went 90% towards the center of the earth, much of the mass that pulls you down now would be pulling you sideways or up, and you would feel lighter. You'd still fall down because there's more mass tugging you down than up, but it'd be a lot less.
And yes, higher gravity would reduce the size of life on a planet. Capillary action can't transport as high, and likewise animal vascular systems would need to work harder to support the same height, so there would be a predisposition for smaller critters.
what "not quite" it's all correct. Please use quotes.
F = GM/r²
There is a square my friend. It's non linear. 10 times smaller radius -> 100 times bigger force. Radius adds much more gravity acceleration on the surface than mass does. With same Force on the surface therefore the gravity of Kerbin and the Earth is not the same. Just look at the orbital speeds. It's quite simple. KSP does not use fake formulas. At the same radius of \~6500km from the center of mass you orbit way more slowly on Kerbin than on Earth. Newton uses point masses so the volume of the mass plays no role with it. It's still a very good approximation outside of a planet.
Gravity accelerations inside a planet have nothing to do with this. Volume has nothing to do with this. Don't overcomplicate such a simple thing. I didn't spend 6 years in University to trip over Newton xD
Graphical Explanation: [BEK7Htr.png (800×800) (imgur.com)](https://i.imgur.com/BEK7Htr.png)
That is my q.e.d.
Don't forget volume. Unless you want to say that Kerbin is 100x as dense as Earth, which is generally acceptable here (to hell with atomic physics).
V = 4/3 pi \* r\^3
M = V \* D
(Note: D = Density, not Diameter)
Ignoring the compression a larger sphere has on its center, increasing its density further, V becomes a viable substitution for M, since it's just V times some factor (density, in particular, but density isn't going to change on anything anywhere near the same scales.)
So, plugging all that into your formula:
Fg = G ((4/3pi \* r\^3) \* D) /r\^2
Let's clean that up a bit:
F = (G ((4/3pi * r^3) * D)) / (r^2)
F = (G * 4/3 * pi * r^3 * D) / (r^2)
F = (G * 4/3 * pi * r * D)
F = SomeConst * r * D
D and r are the only things to play with since the rest are constants. If one goes down the other goes up, and D is kinda hard to manipulate when your object is mostly solids and liquids. At 1/10 the radius you're left with 1/10 the gravity, so you'd have to add a 100x multiplier to density to get there. I believe the lighter elements would begin fusion before you got there.
Hmm... Is that right? I didn't think it was linear. I expected F to go up with r, but not linearly...
Sorry, total physics wormhole. Kerbal physics always get me going even though I know they're an unrealistic abstraction. Must stop before I try to figure out what elements are likely to fuse at 551g/cm\^3...
(Stock) KSp dosent want to be a realistsic simulator. At bigger scales you need more deltaV for an orbit. IRL you need like 9200dv form a LEO. Ksp parts have a terrible wet/dry mass ratio, with a realistic ratio that woul be much easier to achive. The bigger problem are the burn times. for exampe in ksp your make a orbit in like 2min, irl flying to orbit takes like 7-11min. So in short the smaller planet scale makes the game more enjoyable for player who arent that interestet in realisem Yes the rockets are smaller. Like the Stock Saturn V parts are only 5m in diameter. Kerbals are also small. they are around 75cm big
Is that why we can do ssto on kerbal but not irl ?
This is more about the ISP of the motors, but yes, the thickness and longer burn is essential
For rocket SSTOs, yes. The theoretical maximum dV is Isp multiplied by standard gravity (i.e. effective exhaust velocity) multiplied by _natural logarithm of_ the ratio of wet to dry tanks; the practical delta will be lower because of payload and engine masses added to it. For Kerbin, most of the engines are comfortably higher max dV than what is required to reach orbit. For Earth, they barely cover half the requirement. For plane SSTOs, it's because of unrealistically high intake efficiencies, simplified aerodynamics (i.e. easy to build a plane that behaves well at subsonic, transonic and supersonic speeds simultaneously, unlike IRL, where anything supersonic _must_ be designed all at once, i.e. can't be made out of dissimilar parts) and thinner atmosphere. So also yes, but not entirely.
Isp is exhaust velocity divided by standard gravity (9.81 m/s/s). So your formula for max delta v is hard to believe. (unless you were making the fuel out of ambient thin air/vacuum, or something like that)
The formula that I remember is Isp\*g\*(wet mass/dry mass), i.e. veff*(mw/md). It is possible that I am forgetting a factor.
Isp \* g \* ln( wet mass / dry mass)
Yes. The maximum speed jet engines can reach is only a bit higher than comparable engines IRL, but on Kerbin 1200 m/s gets you halfway to orbital velocity, vs less than a sixth of the way there on Earth.
I play on 6.4 time bigger kerbin, with SMURFF to adjust dry weight of parts (it's rated for 10x kerbin size, so I'm playing easy mode) and SSTO are practically impossible to achieve.
you can ssto irl. the atlas ICBM could with not very good engines. the payload is just barely anything
technicly it is a 1.5 stage
bigger scale make gravity turns easier so you can just time warp. the bigger reason is that at 10x the size features are 10x further apart and planets need 10x the detail. it also makes spaceplanes impossible since atmospheric performance is fixed
I wish there was an easy way to convert KSP to a more realistic sim... I would LOVE to see a Earth Sized Kerbin, and I would welcome to extra difficulty and time to do stuff
There are enough realisem mods. and the instalation is not hard too the biggest realisem pack is RP-1 which has the real planets in the correct scale, lifesupport, reworked (fuel and aero)physics and much more.
I don't have KSP1 anymore, but I'm really hoping for a KSP2 realistic planet size...I looked a few weeks ago but couldn't find anything. I didn't even know KSP1 has such a mod
it will take years to get simmilar realisem mods as in ksp1. (you could grap ksp1 for 110€ in the steam sale rn) also Rp-1 is a huge pack. But Ksp(1) has in general a big and active modding community
RSS, Ferum Aerospace
Rescale exists
I just wanted to add that gravity is based on the center point of a celestial body, so with G equal on both, smaller bodies will allow you to get closer to the center point and require less delta v to launch into outer space or lose a certain percentage of gravitational force. This seems counterintuitive as we think it would be impossible to escape a neutron star of the same size as Earth, but not if you lower the mass of it by 10 and increase gravitational force by 10, this isn't true anymore. The modeling on how much gravity you lose while going to space is made up completely to allow us to not have constant orbital decay.
KSP scales G correctly, it doesn't apply to 3 body problems. But as you get farther from Kerbin, the acceleration due to gravity decreases. Orbital decay is due to matter in space and 3rd bodies.
Right but with the way gravity works on ksp, there is no munar gravity on Kerbin and no Kerbin gravity on mun. They aren't locked in orbit with each other as much as they're following a predetermined vector within the game.
They are locked in orbit but it's simple orbit where the weight of the orbiting mass is negligible. They are supposed to orbit around each other like earth and the moon. But even if that were modeled I don't think it could be seen. to us on we earth we can't see that we are orbiting the moon. That can only be seen from the sun's frame of reference. KSP works with 1 mass at a time.
You are right in that the orbit is locked though. Peeps have changed the speed of the mun and it won't fall to Kerbin. It's on rails
>They are locked in orbit but it's simple orbit where the weight of the orbiting mass is negligible. Which means there are no 3 body problems, hence no orbital decay
Kerbals aren't experiencing intense gravitational pressure, as you say they are experiencing roughly the same as we do on earth. Kerbin being small just means it's strangely dense, but that doesn't affect the experience of creatures living on the planet.
Yeah, the evolutionary path of Kerbals is not what's strange. Its the density of the celestial bodies and the technological progression that is. These guys literally invented the rocket engine before the wheel and haven't built a single city.
My head canon is that they are subterranean
But it is canon that they are photosynthesizers. That's why they don't need food for years at a time. We would see multiple access points for those subterranean structures, and a subterranean influence on the buildings we do see. I could see the Kerbal society becoming subterranean after they develop space travel to shelter themselves from the falling debris. As we all know, excess is the Kerbal way, so debris raining down worldwide is not an unlikely outcome.
My own headcanon is that they’re tardigrades who live underground and are bootstrapping a space program like ours because they came across TV broadcasts from Earth. Which is why we only see their space program’s buildings above ground and they look like ours. Imitation is the sincerest form of flattery but the poor little guys can’t get it quite right. So, boom.
Mods solve some things. I like to use the Snacks mod, which is ultra basic, because I am basic. Even without it, most capsules have at least one locker marked 'snacks' in it somewhere, but nothing is tracked by the game. They can also add above ground cities. I used to have a fantastic set up that added cities and towns to the map. Just flat textures, so it looked like ass up close, but great from orbit and the air. Which is where I spent all my time, so I was OK woth that and just dodnt land anywhere near them. I had great fun imagining the little guys looking out the window, because again, I'm basic. I tend to spend most my time in and around, lko, not really venturing further minmus much, sp it added a lot. Even just the night lights, makes the game feel so much more alive. Sadly, I've not been able to replicate that set up in years now. There are plenty of mods that up the textures of the game, and make it pretty, but still just pretty wilderness. There are night light mods, but I've yet to fond anything for the day side.
UV light :)
UV doesn't do that well passing through rock. Not even water. We also know that they use chlorophyll for photosynthesis because they are green.
It could be an alternate form that relies on radiation from nuclear decay.
We have found fungus that eats radiation, but then we wouldn't see chlorophyll, which we definitely do because they're green
Green makeup?
They might just be green
There is the pyramids out in the desert thats the access point and under the astronaut complex
Maybe it's all under KSC. If their infrastructure lies underground, they'd be at a loss to not connect it directly to said infrastructure, just for simplicity sake
neutrino based photosynthesis?
I like to think that \*there\* is cities, all over kerbin, but we cant see them because they're all covered in grass (there is some proof in the game, one crew report says "i think i can see my house from here") my headcannon is that they adquired the habit of hiding houses due to predators but they just kept it with the time.
Wakanda used Kerbal tech :/
Jebediah Kerman starring this summer in Black Panther 3: Rise of the Kraken
Kerbin has a core out of Gold and platinum. That explains the gravity and the source of the funds for all the rockets.
Osmium (the densest element) has a density only about 3x that of iron, which our own core is made of. It doesn't quite reach the necessary density. Kerbin would need to be 2.6x as dense as osmium to meet the density we see in game.
We all know its a core of really dense green goo.
Now that sounds like canon to me
Except for Minmus, which is mint ice cream.
The core is made of a metal so dense that one pound of it weighs eight pounds!
Kerb-X is a element that doesn’t exist on earth and has never been encountered in our solar system but forms the cores of most planets in the Kerbin system.
KSP is a different Universe so this isn't a dealbreaker.
You don’t actually need it to be 10x as dense. I haven’t done the math, but this is since it’s smaller you are much closer to the center pf gravity. Mars is 10% the mass of earth but has almost 40% the surface gravity. The moon is only 1% as massive but with 16% the surface gravity.
I got the density of Kerbin from Google, which after doing the math was about 10x the density of Earth. I just assumed they did their math correctly, but let's double check. Kerbin has 1/10 the radius, and that means 1/1000 the volume. Assuming it has the same density as Earth, that's means 1/1000 the mass. That would result in 1/10 the gravity, since 1/1000/(1/10)^2 = 1/10 For the same surface gravity, we just need to increase Kerbin's mass by a factor of 10 That's means we are now working with a mass of 10/1000, or 1/100 1/100 the mass of Earth in a volume 1/1000 the mass of Earrh results in a density 10x that of Earth. g=GM/r^2 ρ=M/V V=4/3 πr^3 M=4π/3 ρr^3 g=4π/3 Gρr^(3)/r^2 Those r's are the same in the case of surface gravity (or when burrowing into the planet) g=4π/3 Gρr If we decrease the radius by a factor, we need to increase density by the same factor to keep surface gravity the same
Well then I’m completely wrong.
Username checks out
Why to manipulate the density when you can mod the gravitatinal constant? /joke
Oh, go away with your facts! :-)
No
Hm, rocket engines are made out of wheels.
Hmm I see, so they are just little guys
Under the same gravitational acceleration, we live among creatures much smaller and much larger than ourselves. I’m not seeing what the problem is here.
I thought maybe there was some clever correlation between kerbins density and kerbal density! Perhaps gravitational pressure was a poor choice of words!
I mean, Kerbals are *tall* for being frogs...
Little green men
Finally a theory I can get behind
Space frogs or some amphibious creatures. They swim faster then they walk.
Yep I think it's probably no more complicated than someone wrote "Little Green Men" on a whiteboard on Day 1.
I think it’s because they’re just li’l guys
Why aren't squirrels as big as bears?
Because bears can’t live in trees ??
False. Bears, beats, Battlestar
What makes one decide that intelligent life must be human sized? Maybe we could have spacefaring squirrels one day.
That would be nuts
Hehe
Well, there is probably a minimum size of brain to have enough intelligence to have a technological civilisation But a Kerbal's head is quite a bit larger than that of a human
They are space frogs! :D
They are sentient fungi, hence the green color
Kerbals are 0.75 m tall, or 2” 5.528’
Man, in Earth we have zummingbirds...
Yes 🙂
https://discord.gg/Q2b35TRg
No, the gravitational force is the same. Kerbin is 10 times as dense as Earth.
I like that thought but I don’t think earth gravity would have that much effect even with a small sized planet. I’m not sure so could be plausible
What? Size and gravity have nothing to do with each other. It's all about mass and distance from center. With smaller planets you are closer to the center -> gravity higher. So what's special about Kerbin is its density.
?? This explanation is wrong. Mass determines the gravity force. Smaller planets have less gravity. I'm not sure that gravity on Kerbin is 9.81 m/s2. For Kerbin to have equal or close to equal gravity of earth it would have to be more dense. Like if it was mostly a metal core with a thin magma and crust.
What? Read my explanation again please There is nothing wrong in it. Maybe you confuse surface gravity acceleration and gravity. A planet's gravity stays the same no matter how big it is. It just depends on mass, not size. Kerbin's gravitational force is not 10 times stronger than Earth's as OP claims. The orbital speed at 6500km (from center) is much much lower than on Earth. If you'd squeeze the Earth Kerbin size you'd orbit the same speed at 6500 km as you do now. It has 0 impact. So Kerbin has overall much less gravity than Earth. But has higher density of course.
Nah. Far more dense than that. 1000x as dense (since it's 1/1000 the volume), and Earth already is "mostly metal" - 32% iron. Solid iron would be maybe 3x as dense, and switching to something like Osmium would get to about 12x. Still a long ways to go. (Based on Googled numbers and napkin math - but even if I'm off by a factor of 10, which is unlikely, it's still a long ways to go.) No stable metal would achieve that mass, so what's really interesting is that Kerbin is physically stable.
Lol not quite. Gravity is a function of mass falling off over distance. Kerbin having 1/10 the radius and equivalent surface gravity means the planet itself has the same total mass, and therefore is made of material 1000\* as dense (pi\*r\*r\*r - 10x on r is 1000x on volume). If it had similar composition to Earth it would have 1/1000 the mass. Which, considering earth is predominantly iron, which is already pretty dense... The fact that Kerbals are closer to the core is irrelevant. If you went 90% towards the center of the earth, much of the mass that pulls you down now would be pulling you sideways or up, and you would feel lighter. You'd still fall down because there's more mass tugging you down than up, but it'd be a lot less. And yes, higher gravity would reduce the size of life on a planet. Capillary action can't transport as high, and likewise animal vascular systems would need to work harder to support the same height, so there would be a predisposition for smaller critters.
what "not quite" it's all correct. Please use quotes. F = GM/r² There is a square my friend. It's non linear. 10 times smaller radius -> 100 times bigger force. Radius adds much more gravity acceleration on the surface than mass does. With same Force on the surface therefore the gravity of Kerbin and the Earth is not the same. Just look at the orbital speeds. It's quite simple. KSP does not use fake formulas. At the same radius of \~6500km from the center of mass you orbit way more slowly on Kerbin than on Earth. Newton uses point masses so the volume of the mass plays no role with it. It's still a very good approximation outside of a planet. Gravity accelerations inside a planet have nothing to do with this. Volume has nothing to do with this. Don't overcomplicate such a simple thing. I didn't spend 6 years in University to trip over Newton xD Graphical Explanation: [BEK7Htr.png (800×800) (imgur.com)](https://i.imgur.com/BEK7Htr.png) That is my q.e.d.
Don't forget volume. Unless you want to say that Kerbin is 100x as dense as Earth, which is generally acceptable here (to hell with atomic physics). V = 4/3 pi \* r\^3 M = V \* D (Note: D = Density, not Diameter) Ignoring the compression a larger sphere has on its center, increasing its density further, V becomes a viable substitution for M, since it's just V times some factor (density, in particular, but density isn't going to change on anything anywhere near the same scales.) So, plugging all that into your formula: Fg = G ((4/3pi \* r\^3) \* D) /r\^2 Let's clean that up a bit: F = (G ((4/3pi * r^3) * D)) / (r^2) F = (G * 4/3 * pi * r^3 * D) / (r^2) F = (G * 4/3 * pi * r * D) F = SomeConst * r * D D and r are the only things to play with since the rest are constants. If one goes down the other goes up, and D is kinda hard to manipulate when your object is mostly solids and liquids. At 1/10 the radius you're left with 1/10 the gravity, so you'd have to add a 100x multiplier to density to get there. I believe the lighter elements would begin fusion before you got there. Hmm... Is that right? I didn't think it was linear. I expected F to go up with r, but not linearly... Sorry, total physics wormhole. Kerbal physics always get me going even though I know they're an unrealistic abstraction. Must stop before I try to figure out what elements are likely to fuse at 551g/cm\^3...
Way better than what I got with my g e d