Examining The Kerbol System as if it were a real solar system

[Darkday560]

I'll examine the Kerbol System as if it were a real solar system, and pose a few theories based off of said things being found or seen.

First off, Kerbol is small compared to Earth's sun. Kerbol has an equatorial radius of 261,600 kms, while our sun has an equatorial radius of 696,000 kms. That means the "habitable zone" is much smaller, and if Earth was placed into Kerbol's system, it would probably be a bit colder. Now, looking at this habitable zone which I find not very easy to define, it is either very large or the planets are smushed in all around the habitable zone. Proof of this lies on Eve, which is not close enough to the sun to be burnt by radiation or have the waters and atmosphere evaporate, and Laythe, who is so far out AND orbiting a gas giant and still not being frozen from distance. If Jool is technically inside the habitable zone, Eeloo has a chance to have life on it because it occasionally passes near jool's orbit. This I would assume means that Kerbol is producing waves of heat that keep Laythe warm while still not burning Eve and Moho to oblivion, or some strange forces outside of Kerbol are keeping the solar system to what it is.

Another thing is that Kerbol has no visible asteroid belts or comets unless created by the player. Instead infinite comets are found hurling themselves are Kerbin for whatever reason. This could be because of the Nemesis theory placed on our real life solar system, but edited a little. The endless asteroids flying at Kerbin could be a result of a red dwarf similar to Nemesis orbiting fast enough, far away enough, and in the right position that it orbits in a way that flings asteroids from the orc cloud to kerbin, making Kerbol a binary system. This star would have to be orbiting very quickly just inside, outside, or on the orc cloud for it to be able to fling asteroids constantly at kerbin.

I may update this in the future, but I need to go eat for now. Post your arguments and theories below!

[problemecium]

This is a bit of a redundant thread but I'll humor you.

- I see Kerbol as a white dwarf. For small stars, the actual diameter isn't nearly as important to the "habitable zone" as the surface temperature, and white dwarfs have a range of temperatures from Sun-like to piping superheated blue. A relatively cool white dwarf, perhaps with some accreted gas, could possibly have a similar size and color to Kerbol.

- Eve's surface pressure is much higher than Kerbin's or Earth's, making it easier to keep water a liquid - and that's under the assumption that Eve's oceans are water and not something like mercury.

- Laythe could easily be kept toasty by tidal heating considering its proximity to Jool. Europa has no atmosphere, so its surface is frozen, but it's commonly thought that underneath it has liquid water due to tidal heating from Jupiter.

P.S.: Oort Cloud. Not the "orc cloud" xD

[GoSlash27]

I'll examine the Kerbol System as if it were a real solar system, and pose a few theories based off of said things being found or seen.

First off, Kerbol is small compared to Earth's sun. Kerbol has an equatorial radius of 261,600 kms, while our sun has an equatorial radius of 696,000 kms. That means the "habitable zone" is much smaller, and if Earth was placed into Kerbol's system, it would probably be a bit colder. Now, looking at this habitable zone which I find not very easy to define, it is either very large or the planets are smushed in all around the habitable zone. Proof of this lies on Eve, which is not close enough to the sun to be burnt by radiation or have the waters and atmosphere evaporate, and Laythe, who is so far out AND orbiting a gas giant and still not being frozen from distance. If Jool is technically inside the habitable zone, Eeloo has a chance to have life on it because it occasionally passes near jool's orbit. This I would assume means that Kerbol is producing waves of heat that keep Laythe warm while still not burning Eve and Moho to oblivion, or some strange forces outside of Kerbol are keeping the solar system to what it is.

Another thing is that Kerbol has no visible asteroid belts or comets unless created by the player. Instead infinite comets are found hurling themselves are Kerbin for whatever reason. This could be because of the Nemesis theory placed on our real life solar system, but edited a little. The endless asteroids flying at Kerbin could be a result of a red dwarf similar to Nemesis orbiting fast enough, far away enough, and in the right position that it orbits in a way that flings asteroids from the orc cloud to kerbin, making Kerbol a binary system. This star would have to be orbiting very quickly just inside, outside, or on the orc cloud for it to be able to fling asteroids constantly at kerbin.

I may update this in the future, but I need to go eat for now. Post your arguments and theories below!

It could also be that the comets aren't concentrated around Kerbin, but rather that's the only place that allows us to spot them (that's where all of our deep space radars are).

Best,

-Slashy

[Streetwind]

One consideration that should be kept in mind when trying to look at the KSP solar system as if it was real is orbital stability in N-body dynamics.

Most of the orbits are actually decently stable for the time periods that people play in. Eeloo and Jool are in proper resonance, I believe (as Pluto and Neptune are), and as such shouldn't interfere with one another. Mun and Minmus are far enough apart and small enough to not affect each other noticably.

But the Jool system will fall apart rather quickly. First, Vall gets ejected with a swift kick in the behind from Tylo within a short few years. Over the next hundred years or so, Pol and Bop significantly change their orbits, and may also be lost to deep space. Laythe and Tylo remain more or less stable.

[FancyMouse]

P.S.: Oort Cloud. Not the "orc cloud" xD

It should be Ore cloud in Kerbol system

[Asharad]

But the Jool system will fall apart rather quickly. First, Vall gets ejected with a swift kick in the behind from Tylo within a short few years. Over the next hundred years or so, Pol and Bop significantly change their orbits, and may also be lost to deep space. Laythe and Tylo remain more or less stable.

I modeled the Kerbol System using the Universe Sandbox. Tylo quickly disturbed all moons in the Jool system causing them to be absorbed by Jool or Tylo. In less than a year, the only surviving moon was Tylo.

Eve and Kerbin are too close to each other, and their orbits begin to change slowly through the years. Something tugged on Ike and pulled it out of orbit, but I did not see why. The entire Kerbol system is a mess.

The density of the planets (25-45 g/cm^3) is higher than any substance known to man. In our universe, Jool would be solid rock of Unobtainium.

Edited May 27, 2015 by Asharad

[KerikBalm]

Proof of this lies on ... Laythe, who is so far out AND orbiting a gas giant and still not being frozen from distance. If Jool is technically inside the habitable zone, Eeloo has a chance to have life on it

Your Laythe example is already contradicted by Eeloo, which is frozen, and you also forget Val: Frozen.

Laythe has features suggestive of Cauldera, suggesting internal heat is responsible, and thus laythe is not useful for determining the habitable zone.

Duna has an atmospheric pressure that is sufficient to support water, but non is found, only ice caps.

So... conclusion: The habitable zone is inside of Jool.

Maybe if Duna had a thicker atmosphere, it would work.

[Findthepin1]

Laythe has supergreenhouse gases (maybe CFCs). Duna has no water albeit being closer in to Kerbol, because it's in an ice age and all the ice raises the albedo which lowers the temperature. Eeloo and Vall cannot have an atmosphere similar to Laythe's, to allow water on the surface, because they are too small to hold it there (see the last sentence in the second paragraph of Eeloo's page on the wiki). Minmus cannot be made of ice because I had a colony there and one of the thermometers read 278K, or 5C which water can evaporate at. Kerbin has no magnetic field, because it does not have a molten core. This deficiency of a molten core is evidenced by the seeming lack of plate tectonics there (mountains formed likely from impact craters, continents do not fit together, no volcanoes, no undersea trenches, etc). Laythe's and Vall's orbits around Jool (and Minmus' orbit around Kerbin) are also perfectly circular, meaning no tidal energy can be derived from orbital eccentricity. Tidal forces from other moons in their system will still affect them, and so will the gradual slowing of the day because of tidal locking (only on Minmus). Eve probably formed outside its current orbit, and Kerbin's influence put it where it is today.

In a couple of million years Eve's oceans will have evaporated and the pressure and temperature will have gone up there. Also, in a couple million years Moho will be tidally locked to Kerbol, its day is 123 days and its year is 102 days. Vall will become a dwarf planet. So will Bop. Minmus' orbit will become non-circular.

[Spartwo]

Also, in a couple million years Moho will be tidally locked to Kerbol.

Something I've always wanted.

[xtoro]

While this is interesting to read, I hope the OP realizes that it's meant to be playable, not realistic. Squad has said KSP is a game first and a simulator second. While Laythe may be frozen IRL, I'm glad it has water because it makes the moon more interesting.

[problemecium]

The density of the planets (25-45 g/cm^3) is higher than any substance known to man.

On Earth. White dwarfs have a density of 1 billion kilograms per m^3 (i.e. 1000 g/cm^3); neutron stars weigh on par with a fleet of battleships per teaspoon; and black holes, even if one assumes the event horizon is the "surface", have a density far higher than even that.

[tychodin]

This is a bit of a redundant thread but I'll humor you.

- I see Kerbol as a white dwarf. For small stars, the actual diameter isn't nearly as important to the "habitable zone" as the surface temperature, and white dwarfs have a range of temperatures from Sun-like to piping superheated blue. A relatively cool white dwarf, perhaps with some accreted gas, could possibly have a similar size and color to Kerbol.

except even the largest white dwarf would be about 50x smaller than Kerbol. Kerbol is something like a KV star, and as far as stars go, about twice as common as the Sun.

[KerikBalm]

Laythe has supergreenhouse gases (maybe CFCs).

*sigh* and you base that on what? is this some joke because you're also an anthropogenic climate change denier?

Duna has no water albeit being closer in to Kerbol, because it's in an ice age and all the ice raises the albedo which lowers the temperature.

Says who that it is in an ice age?

How do you know what the baseline icecap is for Duna?

Eeloo and Vall cannot have an atmosphere similar to Laythe's, to allow water on the surface, because they are too small to hold it there (see the last sentence in the second paragraph of Eeloo's page on the wiki).

Actually, all the planets except jool are too small to hold on to much of any atmosphere.

Kerbin has no magnetic field, because it does not have a molten core. This deficiency of a molten core is evidenced by the seeming lack of plate tectonics there (mountains formed likely from impact craters, continents do not fit together, no volcanoes, no undersea trenches, etc).

A molten core does not neccessarily mean plate tectonics are active. The topography of kerbin does have many ridges that cannot be impact formed.

While it doesn't have the obvious jigsaw puzzle look like we see on earth around the atlantic, I can't say with confidence anything about Kerbin.

Laythe's and Vall's orbits around Jool (and Minmus' orbit around Kerbin) are also perfectly circular, meaning no tidal energy can be derived from orbital eccentricity.

but they wouldn't be in real life, as they would alter each others orbits.

In a couple of million years Eve's oceans will have evaporated and the pressure and temperature will have gone up there.

Says who? you don't even know what Eve's oceans are.

A couple million years is a REALLY REALLY short time on the astronomical scale. The oceans on Venus lasted longer than that.

Also, in a couple million years Moho will be tidally locked to Kerbol, its day is 123 days and its year is 102 days,

More likely, it will end up like Mercury, which is not tidally locked, but has a spin orbit resonance.

Also... a couple million years is a really really really short time scale for this sort of thing.

Vall will become a dwarf planet. So will Bop. Minmus' orbit will become non-circular.

Yup, that is what the N-body simulations show.. I also seem to recall some question about the long term fate of pol

[Asharad]

On Earth. White dwarfs have a density of 1 billion kilograms per m^3 (i.e. 1000 g/cm^3); neutron stars weigh on par with a fleet of battleships per teaspoon; and black holes, even if one assumes the event horizon is the "surface", have a density far higher than even that.

I was talking about planets. Eve isn't a star but has star-like density.

"The densest transiting exoplanet known is COROT-3b, which has density of 26.4 g/cm^3" . There are debates, but most classify COROT-3b as a brown dwarf star.

The density of Eve is 85 g/cm^3.

The density of Jool is near Earth.

Actually, all of Jool's properties are near Earthlike, except for the green texture.

Edited May 28, 2015 by Asharad

[OhioBob]

According to Physics.cfg, the solar constant at Kerbin is 1360 W/m². From this we can determine that Kerbol's luminosity is 3.16×10²⁴ watts. Using the size of our Sun's habitable zone as a guideline, and adjusting for the difference in luminosity, we can estimate that Kerbol's habitable zone extends from roughly 10 million km to 20 million km. This is roughly from the orbit of Eve to the orbit of Duna.

The only planet with enough mass to have a thick atmosphere is Jool. Based on their mass and temperature, Eve, Tylo, and Laythe might be able to retain a very thin atmosphere of heavy gases (e.g. carbon dioxide). Although Kerbin is larger than either Tylo or Laythe, its warmer temperature makes it less likely to be able to hold onto an atmosphere.

[Findthepin1]

*sigh* and you base that on what? is this some joke because you're also an anthropogenic climate change denier?

Says who that it is in an ice age?

How do you know what the baseline icecap is for Duna?

Actually, all the planets except jool are too small to hold on to much of any atmosphere.

A molten core does not neccessarily mean plate tectonics are active. The topography of kerbin does have many ridges that cannot be impact formed.

While it doesn't have the obvious jigsaw puzzle look like we see on earth around the atlantic, I can't say with confidence anything about Kerbin.

but they wouldn't be in real life, as they would alter each others orbits.

Says who? you don't even know what Eve's oceans are.

A couple million years is a REALLY REALLY short time on the astronomical scale. The oceans on Venus lasted longer than that.

More likely, it will end up like Mercury, which is not tidally locked, but has a spin orbit resonance.

Also... a couple million years is a really really really short time scale for this sort of thing.

Yup, that is what the N-body simulations show.. I also seem to recall some question about the long term fate of pol

I would like to clarify that all I am doing is guessing. So is everyone else here. The planets in KSP with atmospheres can all hold their atmospheres because what matters is the gravity. They're really, really dense. You could theoretically have an object six inches across, with an unrealistic density that gives it about 9.81 meters per second squared gravity. It would be able to hold onto an atmosphere of 1 atm. That atmosphere would be much less massive than Earth's, but still 1 atm, as in Kerbin's scenario. As you say, it could also end up like Mercury. IF Eve's oceans are made of something similar to water, then they would begin to boil somewhere on the planet if its temperature were raised barely two degrees (Eve's maximum temperature is two degrees below the boiling point of water at 5 atm, assuming the Kerbals measure in Kelvin). That is a very risky environment. One particularly hot day at the equator over ocean could set off a runaway greenhouse effect (oceans evaporate, increase air pressure, air traps more heat due to higher mass/density/pressure, increase temperature, more oceans evaporate, etc). I was also assuming Duna was in an ice age because one of the devs once posted that Duna was inspired by something about Mars in an ice age, I regret assuming that now. Either way, the ice has an effect on Duna's albedo.

Also, I do not consider myself an anthropogenic climate change denier, I consider myself an anthropogenic climate change skeptic. This is because I am willing to listen to and consider people's opinions on either side of the debate, and when talking about the subject I try to make my points as logically as possible. It is possible that Laythe has CFCs or some other strong greenhouse gas. I do not dispute the existence of greenhouse gases or their effects, it was not a joke.

Edited May 28, 2015 by Findthepin1

[KerikBalm]

The planets in KSP with atmospheres can all hold their atmospheres because what matters is the gravity. They're really, really dense. You could theoretically have an object six inches across, with an unrealistic density that gives it about 9.81 meters per second squared gravity. It would be able to hold onto an atmosphere of 1 atm. That atmosphere would be much less massive than Earth's, but still 1 atm, as in Kerbin's scenario.

No, it is not surface gravity that matters. It is escape velocity that matters.

On Earth, a gas molecule moving at 8 km/s will be barely suborbital.

A gas molecule moving at <11 km/s will go on very very very eccentric trajectories around earth, but their perapsis will still intersect the top of the atmosphere.

A gas molecule moving at 12 km/s... is gone... that is over escape velocity.

Escape velocity for kerbin is about 3km/sec, orbital is about 2km/sec.

Even mars has a higher escape velocity than Kerbin (mars: 5 km/s)

You should easily be able to tell that some gases that Earth can hold on to, Kerbin would not be able to hold on to (assuming the same temperature).

Kerbin, having a lower escape velocity and warmer temperature (meaning the gas molecules will move faster) than mars, wouldn't hold on to its atmosphere nearly as well as mars.

Now, Eve's escape velocity seems to be about 4.5km/s... but its temperature much higher... it wouldn't even hold on to an atmosphere as well as mars did.

That leaves us with Jool as the only planet to hold on to an atmopshere

[Findthepin1]

Oh ok I understand it now

also at the end of the post *atmosphere*

[OhioBob]

KerikBalm is correct; it's escape velocity that is the key. The rule of thumb that I've heard is that the average speed of a gas molecule has to be no more than about 10% of the escape velocity to be retained over an extended period of time. If the average speed is much more than that, there will be enough molecules exceeding escape velocity that, over billions of years, the gas will slowly be lost. The average speed of a gas molecule is given by the root-mean-squared velocity, which is function of temperature and molecular weight. If we know the escape velocity and temperature, we can compute the minimum molecular weight molecule that a planet can hold onto. For temperature, we can use the sun's luminosity of 3.16×10²⁴ watts and calculate the black body temperature. I estimate the following minimum molecular weights:

[TABLE=width: 250]

[TR]

[TD]Jool[/TD]

[TD]3.3 g/mol[/TD]

[/TR]

[TR]

[TD]Tylo[/TD]

[TD]33[/TD]

[/TR]

[TR]

[TD]Eve[/TD]

[TD]35[/TD]

[/TR]

[TR]

[TD]Laythe[/TD]

[TD]39[/TD]

[/TR]

[TR]

[TD]Kerbin[/TD]

[TD]59[/TD]

[/TR]

[/TABLE]

Clearly Jool can retain a thick atmosphere. Tylo and Laythe might be able to retain some heavy gases, such as carbon dioxide (44 g/mol). Although Eve can theoretically hold onto heavier gases, it's closeness to the sun also means it must deal with a strong solar wind. I doubt Eve would retain an atmosphere. Kerbin really has no chance.

[KerikBalm]

Nor does Duna...

But I guess using those numbers, we'd conclude that their atmosphere (aside from no-chance Kerbin)is probably CO2.

Laythe's oxygen would be continuously lost to space, so it must be replenished... hydrolysis of water? that Hydrogen escapes... why hasn't laythe become dessicated?

O2 would be lost - MW 32

N2 would be lost - MW 28

Water vapor would be lost - MW 18

Helium - LOL, lost, even lost on Eart

Neon would be lost - MW 20

Methane would be lost - MW 16

Ammonia would be lost...

Carbon monoxide would be lost - MW 28

Argon would be retained by all exept Duna and Kerbin - MW 40

Krypton and Xenon would thus be retained (even though they are quite rare) by Kerbin (Duna?)

CO2 would be retained - MW 44 by all except Duna and Kerbin - its questionable for laythe, particularly as we should assume laythe is not in radiative equilibirum, but rather has significant inernal heat. - Although I'm not sure how much that affects the top of the atmosphere where the mean free path becomes significant (you can have hotter gases down low, because they'll collide with another gas molecule before escaping to space - you only need to consider the velocity at the "top" of the atmosphere)

So... Eve can have an Argon/Kr/Xe + CO2 atmosphere, Jool can keep everything except hydrogen (uh oh, that is most of the mass of a gas giant... I guess it is more of an ice giant).

Kerbin loses pretty much everything.

Laythe is questionable. Tylo should have some CO2... but even in game they remark that it is weird that it has nothing.

I'm surprised Eve can even hold on to a CO2 atmosphere.... but OK, I'll trust your math.

[KanadianCerbal]

Isn't a white dwarf the remains of a star after its expanded to critical mass? If this is true than wouldn't it mean that this Kerbol system is not the first? This could also explain the lack of a substantial Oort cloud, comets or asteroids, as whatever was left after the expansion and compression of "Kerbol 1" led to the reformation of the current Kerbol system.

[tychodin]

Isn't a white dwarf the remains of a star after its expanded to critical mass? If this is true than wouldn't it mean that this Kerbol system is not the first? This could also explain the lack of a substantial Oort cloud, comets or asteroids, as whatever was left after the expansion and compression of "Kerbol 1" led to the reformation of the current Kerbol system.

a white dwarf is the core of a star that has ceased fusion. there's no explosion for these stars (unless the white dwarf explodes later). they just go through a pulsational phase where they shed their outer layers and leave the core behind. and like i said earlier, Kerbol is far too large to be a white dwarf.

[KanadianCerbal]

a white dwarf is the core of a star that has ceased fusion. there's no explosion for these stars (unless the white dwarf explodes later). they just go through a pulsational phase where they shed their outer layers and leave the core behind. and like i said earlier, Kerbol is far too large to be a white dwarf.

Oh, thanks for telling me. I guess I didn't see your post earlier, sorry. And thanks for informing me on what a white dwarf is.

[OhioBob]

Nor does Duna...

I didn't put Duna on the list because after Kerbin it's not even close. The minimum MW for Duna works out to be 298 g/mol. Vall is actually next best with MW = 223 g/mol.

I'm surprised Eve can even hold on to a CO2 atmosphere.... but OK, I'll trust your math.

Being close to the sun, Eve obviously has a high black body temperature (327 K), but it also has the second highest escape velocity in the game (after Jool). The high escape velocity is what allows it to hold onto some heavy gases. If Eve where the size of Kerbin, then its minimum MW would be 69 g/mol.

[KerikBalm]

Being close to the sun, Eve obviously has a high black body temperature (327 K), but it also has the second highest escape velocity in the game (after Jool). The high escape velocity is what allows it to hold onto some heavy gases. If Eve where the size of Kerbin, then its minimum MW would be 69 g/mol.

Yea, well, I figured its escape velocity is still lower than mars, and it should be warmer...

Yes, Mars has an atmosphere... but not 5 atmospheres of pressure at the surface.

The atmosphere of Mars is barely there.... for most purposes, Mars has lost its atmosphere.

If Mars lost its atmosphere, I can't see Eve having much chance of retaining its thick atmosphere.