Is Laythe Possible IRL?

[HafCoJoe]

26 minutes ago, MinimalMinmus said:

My guess: Laythe has some very potent greenhouse gases around it, such as CFC (10000 times better than co2). This would be supported by the theory that Jool gets it's green with fluorine and chlorine.

It's also possible to create Ozone from electricity, and considering that Laythe is a giant tidally locked heap of water and air I doubt it would have any problem creating lightning. Also if the water is diluted with something with a lower freezing point that could explain why it isn't frozen at the equator.

[Nathair]

7 hours ago, Abastro said:

Actually there is a mechanism which produces oxygen on the atmosphere: UV rays breaking water vapors into hydrogen & oxygen gas.

This is quite common for planets getting runaway greenhouse effect, since they have relatively high water vapor concentration in its high atmosphere. The hot temperature causes water vapor to go up higher, where it's prone to bombardment of solar UV rays. The resulted hydrogen gas escapes the planet, while the oxygen gas falls to the bottom of the atmosphere due to its high molar mass.

 

The problem is not producing oxygen. Oxygen is the third most common element in the universe! The problem is in ending up with substantial free oxygen remaining in the atmosphere.

[Snark]

Moving to Science & Spaceflight, since this is purely a question about IRL astronomy and geophysics rather than about KSP itself.

[peadar1987]

Numbers time!

Edit: the numbers are wrong, updated, warmer version here: 

From wikipedia, the expected temperature of a planet with no greenhouse effect can be given by:

Where A_abs/A_rad is the effective area of the planet getting heated by the sun (0.5 for slowly-rotating bodies)

L is the luminosity of the sun

a is the albedo of the body, which is about 0.367 for earth.

Sigma is the Stefan-Boltzmann constant

Epsilon is the emissivity of the earth, here taken to be 0.612

D is the distance to the sun.

Plugging these numbers into Wolfram Alpha gives an expected surface temperature for an earth-like body orbiting Jupiter of 61K. Earth's own Greenhouse effect adds about 40K to the temperature, but even with that we're at -170 degrees celsius, well below the sublimation point of CO₂ under atmospheric pressure (-78 degrees celsius).

Even if your body is coal-black and absorbs almost all of the radiation from the sun, the average surface temperature only goes up to 69K.

Now, on earth, the variation between the average temperature and the maximum average temperature is about 25-30K, giving a maximum temperature on our pseudo-Laythe of possible 140K. We still have over 100K to make up before we even get to the melting point of antifreeze.

So the sun isn't enough...

What about tidal heating?

Well Jupiter gets about 54W/m² of solar radiation, which means that an earth-sized planet would get 54W*pi*r², or 6.8*10¹⁵W from the sun.

This calculates that Io generates about 6*10¹⁷W due to tidal forces, less than 1% of which is converted into heat (the rest just moves rock around). The tidal heating seems to depend on the radius of the planet, rather than its mass (which I found surprising), so an earth-sized body would experience about 3x the tidal heating as Io, giving a tidal heating of 3*10¹⁴W, an order of magnitude smaller than the solar radiation.

If we're being reeeally generous (and fudgey), increase this by a factor of ten, and just treat it as doubling the solar energy absorbed by the planet, I can still only manage to increase the expected average surface temperature to 80K.

I'm really struggling to see how we could make this happen. Jupiter is just too far out.

If anyone wants to play around with the values I've used, click here

 

Edited February 3, 2017 by peadar1987

[kerbiloid]

If Jupiter were on 1 AU orbit, and Earth were its moon, no problems with temperature.
Of course, all icy moons and rings were evapourated and dissipated billions years ago.

Main question: how should such big planet like Earth survive or form in such close proximity while Jupiter was forming.
Maybe if the Earth were formed in a triangle Lagrange point (like supposed proto-Moon relative to Earth IRL).

In KSP.
It's rather strange that a hydrogen giant Jool has no icy moons while its between icy planetoids Dres and Eeloo.
Looks like the Jool system got heated some time ago, all ice either evapourated or melted and formed the Laythe ocean. (As Laythe is enough heavy), So, only rocky moons survived.

Another strange thing is icy Minmus on the same orbit like wet Kerbin with icy caps and rocky Mun.
Probably, either Minmus appeared here not long ago (a captured iceteroid), or Kerbin is anomalously hot.

Maybe the key is Mun orbit (an ideal circle exactly in equatorial plane) and Kerbin ocean,
Maybe this means that Mun is a planetoid captured by Kerbin and tidally locked. And Kerbin is indeed beyond the habitable zone.
Say, while the Mun rotation is locked, the tidal bulges heat the Kerbin's equator melting ice and keeping the ocean hot. While the polar caps are far from bulges and stay cold.

All this means that temperature balance in KSP differs a lot from what we have in Solar System. And the planet system KSP has dynamical equlibrium. Once being heated, it slowly gets cold.
Probably that was one same event which heated Jool system and threw the Mun into Kerbin.
Either Kerbol was hotter, or a rogue star passed by (and also that's why Eeloo and Dres are before and after the Jool orbit.)

P.S.
Btw in 2012 Kerbol was reddish. I even thought it's a red dwarf.
Now it's yellow-white. Is it getting hotter?

Edited February 1, 2017 by kerbiloid

[Martian Emigrant]

A long, long time ago I read:

The long story short:

A man travel for 150 years (Ship-time) at relativistic speed and comes back to the solar system 3 millions years after his departure.

His ship (AI) and him can't find the earth and recognize the system.

The sun is a giant red star and there is no earth were it should be. All the planets are "Wrong".

They finally find that the earth as been moved and now orbit Jupiter.

The climate, inclination, seasons, life is all wrong. Civilisation as declined. The adventure begins.

 

ME

[PB666]

20 hours ago, A_name said:

Like the title says, would a planet with oxygen and liquid water be possible IRL, say, in orbit around Jupiter?

In our system, no. In the kerbin system. Consider that the density of Kerbin is 10 times that of earth, as with every other world. Its not clear what the solar output is but solar panels produce more energy, and yet kerbels don't die from sun exposure and grass grows, this indicates that the physics has been  contrived for the sake of game play. Consequently we need to reject the hypothesis on the lack of precedence and wait for confirmatory evidence within the visible universe.

In our universe, it is very unlikely that a planet one/tenth the volume of earth with the same mass and 10x density exists. It is unlikely that an earth-like planet could exist in orbit around Jupiter.

For several reasons.
Jupiter would likely make our persistent magnetic field unstable.
Jupiter creates a much greater potential of asteroid and comet strikes because:

   1. Its farther from sun and it drafts bolloids from outside the inner system, it is the major graveyard, this would bring oxygen in the form of ice, but it would also with lack of stable magnetic feild cause evolution of hydrogen.
   2. Oxygen has a dependency of living material, such life does not fair too well under bombardment, persistently. The constant bombardment would favors forms of life that could live both being frozen for years on end and also being resilient to extreme heat.

Jupiter's EM emission in the the photosynthetic part of its spectrum is minimal; and yet  the sun is so far away photosynthetic life would have to be far more energy efficient than life on earth. THere is a dependency of oxygen on both liquid water and life, so oxygen is not possible.

 

[Nathair]

5 hours ago, peadar1987 said:

So the sun isn't enough...

What about tidal heating?

And what about the radiogenic heating I mentioned above? There's also residual accretion heating and heating from core formation (gravitational heat) to consider. In a youngish body (and depending upon composition) these could contribute a significant amount to the planet's heat budget.

[CSE]

3 hours ago, PB666 said:

[...]
There is a dependency of oxygen on both liquid water and life, so oxygen is not possible.

 

If I understand it right, free oxygen is possible (maybe not realistic, but possible) provided that the other atmosphere and surface chemistry is already fully oxidized. So as long as we don't know any other constituents of Laythe than its oxygen and water, and provided the ore is composed of oxides, then we're still in the realm of possibility. Saved by ignorance, as it were.

Lovelock: A physical basis for life detection experiments.

Edited February 1, 2017 by CSE
typo

[PB666]

14 minutes ago, Nathair said:

And what about the radiogenic heating I mentioned above? There's also residual accretion heating and heating from core formation (gravitational heat) to consider. In a youngish body (and depending upon composition) these could contribute a significant amount to the planet's heat budget.

You need light to make oxygen, you need photochemistry. If you don't have some higher EM spectrum, not the type that cause atoms in molecules to wobble, but the type that cause electrons in a stable orbit to achieve a higher orbit, this unstable state allows the production of [H*] which then goes on to form H-C or H-Si or H-N, leaving the oxygen as a hydroxide free radical. Heat makes the atoms in a molecule wobble, but does not have the energy to place electrons in molecules in higher orbit. Thus if you are thinking about oxygen you need photochemistry.

Oxygen (diatomic) is the high energy state of oxygen. Its lower energy states are H20 and C02. These are the prefer state, heat will only force oxygen toward a lower energy state, that is heating hydrogen with oxygen will cause an expected reaction, heating carbon with oxygen will produce an expected reaction (Coal and Air is essentially this). Heat encourages the loss of oxygen from the system. If you then have a black body radiation source, in standard terms this means more low energy than high energy EM, which means the favor is toward degradation. The suns spectrum is abundant at the high end, this allows larger amounts of light in EM capable of producing much more complex photochemistry, without this we would not have life on earth as we know it or oxygen.

 

[Reusables]

8 hours ago, Nathair said:

The problem is not producing oxygen. Oxygen is the third most common element in the universe! The problem is in ending up with substantial free oxygen remaining in the atmosphere.

Oops. What I meant was free oxygen gas.

6 hours ago, peadar1987 said:

Numbers time!

From wikipedia, the expected temperature of a planet with no greenhouse effect can be given by:

Where A_abs/A_rad is the effective area of the planet getting heated by the sun (0.5 for slowly-rotating bodies)

L is the luminosity of the sun

a is the albedo of the body, which is about 0.367 for earth.

Sigma is the Stefan-Boltzmann constant

Epsilon is the emissivity of the earth, here taken to be 0.612

D is the distance to the sun.

Plugging these numbers into Wolfram Alpha gives an expected surface temperature for an earth-like body orbiting Jupiter of 61K. Earth's own Greenhouse effect adds about 40K to the temperature, but even with that we're at -170 degrees celsius, well below the sublimation point of CO₂ under atmospheric pressure (-78 degrees celsius).

Even if your body is coal-black and absorbs almost all of the radiation from the sun, the average surface temperature only goes up to 69K.

Now, on earth, the variation between the average temperature and the maximum average temperature is about 25-30K, giving a maximum temperature on our pseudo-Laythe of possible 140K. We still have over 100K to make up before we even get to the melting point of antifreeze.

So the sun isn't enough...

What about tidal heating?

Well Jupiter gets about 54W/m² of solar radiation, which means that an earth-sized planet would get 54W*pi*r², or 6.8*10¹⁵W from the sun.

This calculates that Io generates about 6*10¹⁷W due to tidal forces, less than 1% of which is converted into heat (the rest just moves rock around). The tidal heating seems to depend on the radius of the planet, rather than its mass (which I found surprising), so an earth-sized body would experience about 3x the tidal heating as Io, giving a tidal heating of 3*10¹⁴W, an order of magnitude smaller than the solar radiation.

If we're being reeeally generous (and fudgey), increase this by a factor of ten, and just treat it as doubling the solar energy absorbed by the planet, I can still only manage to increase the expected average surface temperature to 80K.

I'm really struggling to see how we could make this happen. Jupiter is just too far out.

If anyone wants to play around with the values I've used, click here

 

Calculate the greenhouse effect of Venus, it should be bigger than 30. So the temperature could be still near the freezing point of water even if it is placed on 5AU. So, it's not that far.

It's just not something earthy atmosphere can give.

3 hours ago, PB666 said:

For several reasons.
Jupiter would likely make our persistent magnetic field unstable.
Jupiter creates a much greater potential of asteroid and comet strikes because:

   1. Its farther from sun and it drafts bolloids from outside the inner system, it is the major graveyard, this would bring oxygen in the form of ice, but it would also with lack of stable magnetic feild cause evolution of hydrogen.
   2. Oxygen has a dependency of living material, such life does not fair too well under bombardment, persistently. The constant bombardment would favors forms of life that could live both being frozen for years on end and also being resilient to extreme heat.

Well, Ganymede retains some of its own magnetic field which is just a bit under the surface on the high latitude. Since the Earth is much bigger, magnetic field will be big enough to pull the boundary out of its surface/atmosphere.

Also, oxygen is not dependent on the presence of life, try searching exoplanets with oxygen. water vapor broken by either UV ray or cosmic rays produces oxygen gas on high atmosphere. A common planet in process of runaway greenhouse effect can experience it, as I said earlier.

EDIT: Look at the atmosphere part of Ganymede, it has tenuous oxygen molecule atmosphere caused by some radiation.

Edited February 1, 2017 by Reusables
Some more explanation after looking at the reply

[PB666]

3 minutes ago, CSE said:

If I understand it right, free oxygen is possible (maybe not realistic, but possible) provided that the other atmosphere and surface chemistry is already fully oxidized. So as long as we don't know any other constituent's of Laythe than its oxygen and water, and provided the ore is composed of oxides, then we're still in the realm of possibility. Saved by ignorance, as it were.

Lovelock: A physical basis for life detection experiments.

Planets are made of reductants, without reductants there cannot be planets. For example the earth is composed of an iron core, this core is not any type of iron in particular its molten and near molten iron as you might find in a rot iron smelter. If you take this  iron an place it in a solution a voltmeter and some mild oxidant like potassium permangenate on the the other side you will get a very nice current. Thats a redox reaction.

Oxygen reacts with
Iron
Sodium
Magnesium
Lithium
Potassium
Copper
Aluminum
Boron
Nitrogen
Sulfur

Just about everything that would hold a planet together oxygen reacts with.

So the question is why do we have oxygen on earth.

The reason is that the bioshere is a very thin layer and in this very thin layer Calcium is locked away as calcium carbonate, silicon is already oxidized to silicates, iron sank but what is exposed are iron oxides. So basically gravity drove the reduce metals down, and the lighter and more volatile substances stayed up. Life, photosynthesis split Oxygen off of CO2, and made wood, that then made coal, which is buried away from the oxygen where its stable for billions of years. As a consequence we have an excess of oxygen and a deficit of carbon. If we burn all the carbon then we deplete the oxygen and have an abundance of green house gas. There was in a period of our earth a time when iron could be found in the more soluble +1 and +2 oxidation states (as is sometimes found in hemoglobins and cytochromes) because the conditions within the cells reflect the early redox state of our world. As photosynthesis began the redox state of the oceans began to rise from below -500mV to the current state between 0 and 500mV. This rise in redox cause iron to precipitate from the oceans, and deep seas saw iron accumulate in huge deposits that we no harvest for iron. To make iron from these however requires the heating up and atomization of iron sometimes in the presence of coal to produce slag iron or steel. Without photosynthesis this would not have happened. Our oceans would have stayed a nice red color the sea floor would have been black with iron sulfides (dig down about 4 inches at the beach, not the smell and the black sands). The sulfate in seawater would have been far lower, the amount of lower oxidations states of sulfur would be much higher.  

Occasionally a coal vein or carbon sink undergoes subduction at a techtonic convergence, the material goes down, and as the heavies dissociate from the volatiles the volatiles work their way to the surface causing a specific form of volcanism common about 100 to 200 miles from the surface fault. There are periods in earths history were this has causes a spike of CO2 and altered the climate for 10s of millions of years before cooling down again. What cools the climate down is the activity of photosynthetic life this removes and deposits Carbon and increases O2 in the atomsphere. 

 

[CSE]

So is there something in the way that planets form which means there's always an excess of reductants, in contact with the atmosphere, over the atmosphere's oxygen, as there was in Earth's case? Is this true regardless of whether the oxygen arrives at initial formation or from cometary bombardment?

[PB666]

21 minutes ago, Abastro said:

Oops. What I meant was free oxygen gas.

Calculate the greenhouse effect of Venus, it should be bigger than 30. So the temperature could be still near the freezing point of water even if it is placed on 5AU. So, it's not that far.

It's just not something earthy atmosphere can give.

Well, Ganymede retains some of its own magnetic field which is just a bit under the surface on the high latitude. Since the Earth is much bigger, magnetic field will be big enough to pull the boundary out of its surface/atmosphere.

Also, oxygen is not dependent on the presence of life, try searching exoplanets with oxygen. water vapor broken by either UV ray or cosmic rays produces oxygen gas on high atmosphere. A common planet in process of runaway greenhouse effect can experience it, as I said earlier.

EDIT: Look at the atmosphere part of Ganymede, it has tenuous oxygen molecule atmosphere caused by some radiation.

Thats an oxygen dynamic though, because the atmosphere is so thin it can exist for a period but as so as you add heat and a reductant, time it will equilibrate to zero.

IOW there is an insuitable amount of oxygen to breath, conduct oxygen based life, etc.

SO the gedanken experiment is here, suppose we gave Jovian-laythe an atmosphere with earth like pressure (although at the temperatures you state, sorry that pressure will not hold up because gases start to sublimate and precipitate). But lets say there is an evil genious who constantly detonate atomic bombs in underground cavity heating the surface gases up so they stay up.

WHat kind of pressure can we expect for oxygen. Imagine an oxygen free radical, what are its potential mates -  we have iron, carbon, hydrogen, ect. So imagine you are going to form a dimer, whats going to get to it first, iron, carbon, sulfur. All of these reactions are pretty low kinetic energy reactions, the highest energy reaction is O, O reaction - this is because there is both a kinetic and thermodynamic problem. So for instance once O reacts with Carbon, its going to stay with the carbon for a very long time, in liquid it will exchange with water oxygen, but thats about it. So at a earth like pressure and temperature but no active carbon production, oxygen becomes oxides of metals, carbons or non-metalic substances. 

 

[Reusables]

1 minute ago, PB666 said:

Thats an oxygen dynamic though, because the atmosphere is so thin it can exist for a period but as so as you add heat and a reductant, time it will equilibrate to zero.

IOW there is an insuitable amount of oxygen to breath, conduct oxygen based life, etc.

SO the gedanken experiment is here, suppose we gave Jovian-laythe an atmosphere with earth like pressure (although at the temperatures you state, sorry that pressure will not hold up because gases start to sublimate and precipitate). But lets say there is an evil genious who constantly detonate atomic bombs in underground cavity heating the surface gases up so they stay up.

WHat kind of pressure can we expect for oxygen. Imagine an oxygen free radical, what are its potential mates -  we have iron, carbon, hydrogen, ect. So imagine you are going to form a dimer, whats going to get to it first, iron, carbon, sulfur. All of these reactions are pretty low kinetic energy reactions, the highest energy reaction is O, O reaction - this is because there is both a kinetic and thermodynamic problem. So for instance once O reacts with Carbon, its going to stay with the carbon for a very long time, in liquid it will exchange with water oxygen, but thats about it. So at a earth like pressure and temperature but no active carbon production, oxygen becomes oxides of metals, carbons or non-metalic substances. 

I think the tidal force ripping off the atmosphere is the bigger problem. IRL Laythe could have higher temperature from massive greenhouse effect, but tidal force would prevent it from retaining its atmosphere.

Besides, what happens if all of those materials is already oxidized? If it is ejecting water through heavy volcanism and water vapor partly dominating the atmosphere goes up to high atmosphere where it'it's decomposed. Maybe it can par with the ejected mantle substances, oxidizing it immediately.

(It can't just retain its atmosphere as stated above, but just a guess)

[PB666]

25 minutes ago, CSE said:

So is there something in the way that planets form which means there's always an excess of reductants, in contact with the atmosphere, over the atmosphere's oxygen, as there was in Earth's case? Is this true regardless of whether the oxygen arrives at initial formation or from cometary bombardment?

LIst the atomic oxidants. What is the frequency of flourine, chorine, oxygen, iodine, bromine.

What is their natural frequency in the universe, in our galaxy or in interstellar space.

The bond energy for double bonded oxygen is 119 kcal per mole, which is only slightly higher than O-H bond at 110 kcal permole. Thus the assumption is that oxygen exist between

::O*-O*:: state (unstable and prone to reduction) and ::O=O::. This is not the case for C02

See wikipedia:

Electronegativities and bond lengths

The C–O bond is strongly polarized towards oxygen (electronegativity of C vs O, 2.55 vs 3.44). Bond lengths for paraffinic C–O bonds are in the range of 143 pm – less than those of C–N or C–C bonds. Shortened single bonds are found with carboxylic acids (136 pm) due to partial double bond character and elongated bonds are found in epoxides (147 pm).^[5] The C–O bond strength is also larger than C–N or C–C. For example, bond strengths are 91 kilocalories (380 kJ)/mol (at 298 K) in methanol, 87 kilocalories (360 kJ)/mol in methylamine, and 88 kilocalories (370 kJ)/mol in ethane.^[5]

Carbon and oxygen form terminal double bonds in functional groups collectively known as carbonyl compounds to which belong such compounds as ketones, esters, carboxylic acids and many more. Internal C=O bonds are found in positively charged oxonium ions. In furans, the oxygen atom contributes to pi-electron delocalization via its filled p-orbital and hence furans are aromatic. Bond lengths of C=O bonds are around 123 pm in carbonyl compounds. The C=O bond length in carbon dioxide is 116 pm. The C=O bonds in acyl halides have partial triple bond character and are subsequently very short: 117 pm. Compounds with formal C–O triple bonds do not exist except for carbon monoxide, which has a very short, strong bond (112.8 pm). Such triple bonds have a very high bond energy, even higher than N–N triple bonds.^[6] Oxygen can also be trivalent, for example in triethyloxonium tetrafluoroborate.

 

The last part has relevance because in a very cold climate there is a preference to form CO bonds as these exhibit the greatest stability, and in such a cold climate once stability of this sort is reached it is maintained. Once you get into space where there are free radicals (e.g. plasma) and higher energy EM the stable state can be preserved, but when you are talking about kelvin in the double digit temperatures, sublimated C02 is the preferential state of volatile oxygen.

There is another problem in deep space, during the sedimentation of planets themselves, if the surface and mantle energies never reach a certain point, then the metal oxides from space will never preferentially undergo heat induced reduction and expulsion of volatile gases, which means for planets in the outer solar system you will find more oxides in the mantel than in the inner solar system.

 

I should point out this is the biggest problem with climate change that the earth faces. Fixation of oxygen is a very energy intensive process in mass, in the rawest calculations about 1/1000th of the energy that reaches the growing biosphere results in generationally stable bonds energy formation. The rest undergoes liberation as heat. Of course our chemist could find a more efficient way, but duplicating what life does is very difficult task, doing it better is more difficult also. Releasing the stored energy in Oxygen and Carbon reserves is relatively easy, returning that energy is difficult. It becomes appreciably more easy as CO2 levels rise, because the disequilibrium that favors destruction of O2 relaxes as O2 concentrations fall (O2 really is the driver of heterotrophic life on earth, not carbon). As O2 falls heterotrophs can still exist, but their rates of metabolism must fall. This then allows carbon fixation to increase stability under a variety of 'overgrowth' situations that will more likely result in coal formation. Unfortunately those situations exist under circumstances in which humans also have asphixiated.

Edited February 1, 2017 by PB666

[kerbiloid]

As I've read, huge amounts of pure oxygen should be released on the terminal phase of a core formation, right before the geological death of the planet.
That's because iron oxides decaying under pressure would release pure iron, pure oxygen and less oxidized iron.
So, that oxygen will raise up to the surface and make the last Earth atmosphere consisting mostly of oxygen. This will increase greenhouse effect and finish the remains of life on the Earth. (Bacteries and so).

Edited February 2, 2017 by kerbiloid

[Findthepin1]

Maybe it's temporary. Maybe Laythe was hit by something in geologically recent times that warmed it up a lot and now it's just cooling back down to normal. 

[WinkAllKerb'']

short version:

%%starsize+%%starage <=> %%planetdistance%%planetsize%%variousmendeileivtableelement%%atmosphere%%temperature%%liquids

if not totally accurate in all the details that's more or less the concept "primitive soup need liquid" not especially water

Edited February 2, 2017 by WinkAllKerb''

[Hannu2]

I think that oxygen rich atmosphere would be quite probable around ocean planet. Solar ultraviolet radiation breaks water molecules in upper atmosphere and light hydrogen escapes. Soil absorbs some amount of oxygen, but when most elements are oxidized to stable compounds, like on Earth when cyanobacteria began photosyntesis couple of billions of years ago, oxygen absorption ceases and it begins to accumulate in atmosphere.

If Jupiter had a large enough moon, like Earth, maybe it could have almost global ocean like Laythe and thick enough atmosphere to keep ocean at liquid state. A significant mass fraction of outer solar system moons are water (much more than Earth have). But certainly such an atmosphere would have too high pressure and oxygen partial pressure for humans.

[WinkAllKerb'']

@hannu being sizes (and their "compound") and pressure is something very versatile at atomic molecular scale // external biological membrane // darwin and all "life find a way" alike

human are not the sole model or option available even if human are often pleased to think so

Edited February 2, 2017 by WinkAllKerb''

[ProtoJeb21]

The real issue in getting a Laythe-like object IRL is size. Remember, everything in KSP is 1/10th their real size, except the Sun. IRL, Laythe will be scaled up to a 5,000 km radius, which is about 0.785 Earth radii. An object that size with an Earth-like composition will be around 45% the mass of our planet. This would be WAY too massive to form around a 1 Jupiter mass (318 Earth mass) gas giant. Moons that formed naturally around a gas giant will have at least 0.0001 times the mass of their parent planet. If Jool has the same mass as Jupiter, the most massive moon should be around 0.035 Earth masses. See the problem? Laythe would have to have formed around a much more massive planet, somewhere between 4 and 15 times the mass of Jupiter. It could acrete naturally or eat other moons to reach that mass. However, it is highly unlikely that Laythe will have a substantial iron core. I predict a mass of about 0.37 Earths for a mostly silicate-dominated moon with between 0.4% and 1% water.

Now to the problem of water. An ice moon could be left with 0.4-1% water ice if it had suffered multiple collisions with other large moons, like with what could've made Laythe so big. But that ice has to melt, obviously. All those collisions could've helped the moon keep warm for a longer amount of time and possibly cause more volcanism. This may lead to a significant greenhouse effect, putting too much volcanic gases in the atmosphere for Kerbals to breathe. It's most likely that a Laythe-like moon would thaw out as its parent planet migrated into the habitable zone.

Finally, there's the issue with oxygen. Life is the obvious choice for an answer, but I have an idea of how it can occur without the presence of microbes. First, this moon's atmosphere has to be at the right pressure to let just a bit of the water evaporate. Its sun must also be putting out more UV radiation than our sun, or a similar amount if the Laythe analogue is in the habitable zone. These two factors would cause some of the water to rise into the atmosphere and be broken into oxygen and hydrogen. Some of it could recombine to create water clouds and cause ocean-replenishing rain. Any leftover oxygen would be sparse, but detectable. Another reason why Kerbals won't breathe it.

[Reusables]

4 hours ago, Hannu2 said:

I think that oxygen rich atmosphere would be quite probable around ocean planet. Solar ultraviolet radiation breaks water molecules in upper atmosphere and light hydrogen escapes. Soil absorbs some amount of oxygen, but when most elements are oxidized to stable compounds, like on Earth when cyanobacteria began photosyntesis couple of billions of years ago, oxygen absorption ceases and it begins to accumulate in atmosphere.

It's improbable for cold planets like the Earth, though. Cold trap keeps the water vapor from getting higher by condensation and precipitation - clouds.

Nevertheless, I think it's obvious that Laythe can't retain its atmosphere due to the tidal force. It's simply too close to the Jool.

What will the orbital parameters be if Laythe is scaled up for IRL?

[magnemoe]

15 hours ago, PB666 said:

Planets are made of reductants, without reductants there cannot be planets. For example the earth is composed of an iron core, this core is not any type of iron in particular its molten and near molten iron as you might find in a rot iron smelter. If you take this  iron an place it in a solution a voltmeter and some mild oxidant like potassium permangenate on the the other side you will get a very nice current. Thats a redox reaction.

Oxygen reacts with
Iron
Sodium
Magnesium
Lithium
Potassium
Copper
Aluminum
Boron
Nitrogen
Sulfur

Just about everything that would hold a planet together oxygen reacts with.

So the question is why do we have oxygen on earth.

The reason is that the bioshere is a very thin layer and in this very thin layer Calcium is locked away as calcium carbonate, silicon is already oxidized to silicates, iron sank but what is exposed are iron oxides. So basically gravity drove the reduce metals down, and the lighter and more volatile substances stayed up. Life, photosynthesis split Oxygen off of CO2, and made wood, that then made coal, which is buried away from the oxygen where its stable for billions of years. As a consequence we have an excess of oxygen and a deficit of carbon. If we burn all the carbon then we deplete the oxygen and have an abundance of green house gas. There was in a period of our earth a time when iron could be found in the more soluble +1 and +2 oxidation states (as is sometimes found in hemoglobins and cytochromes) because the conditions within the cells reflect the early redox state of our world. As photosynthesis began the redox state of the oceans began to rise from below -500mV to the current state between 0 and 500mV. This rise in redox cause iron to precipitate from the oceans, and deep seas saw iron accumulate in huge deposits that we no harvest for iron. To make iron from these however requires the heating up and atomization of iron sometimes in the presence of coal to produce slag iron or steel. Without photosynthesis this would not have happened. Our oceans would have stayed a nice red color the sea floor would have been black with iron sulfides (dig down about 4 inches at the beach, not the smell and the black sands). The sulfate in seawater would have been far lower, the amount of lower oxidations states of sulfur would be much higher.  

Occasionally a coal vein or carbon sink undergoes subduction at a techtonic convergence, the material goes down, and as the heavies dissociate from the volatiles the volatiles work their way to the surface causing a specific form of volcanism common about 100 to 200 miles from the surface fault. There are periods in earths history were this has causes a spike of CO2 and altered the climate for 10s of millions of years before cooling down again. What cools the climate down is the activity of photosynthetic life this removes and deposits Carbon and increases O2 in the atomsphere. 

 

Agree on the first point, then photosynthesis started oxygen levels stayed low for a billion years as the oxygen reacted with the ground, oxygen levels just started reaching today levels 600 million years ago 
however existing coal is far newer think most is 250 million years or younger, amount of coal would be far less than the amount of oxygen too. Guess most of the original carbon ended up on the deep sea floor who went back in the mantle, remember that the oxidation phase was many times longer than it was since the cambium explosion of life, coal deposits are not stable on this time scale and life back then was mostly in ocean. Some carbon probably became rock too. 
I guess the atmosphere was thicker back then, extra co2 has been added by volcanoes and some water has split and only the oxygen was left but overall the setting is stable. 
 

5 hours ago, Hannu2 said:

I think that oxygen rich atmosphere would be quite probable around ocean planet. Solar ultraviolet radiation breaks water molecules in upper atmosphere and light hydrogen escapes. Soil absorbs some amount of oxygen, but when most elements are oxidized to stable compounds, like on Earth when cyanobacteria began photosyntesis couple of billions of years ago, oxygen absorption ceases and it begins to accumulate in atmosphere.

If Jupiter had a large enough moon, like Earth, maybe it could have almost global ocean like Laythe and thick enough atmosphere to keep ocean at liquid state. A significant mass fraction of outer solar system moons are water (much more than Earth have). But certainly such an atmosphere would have too high pressure and oxygen partial pressure for humans.

This is predicted, it require an star who is pretty large and have high temperature for more UV light. Earth has this effect but its not very important here as its too low.
So you could end up with an ocean planet getting an thick atmosphere with mostly oxygen and no life simply as its too hot for it. 

Wonder how far out an planet with say 10 bar pressure and mostly co2 would keep warm? You could use methane too but life would eat this and the temperature would drop. 
Issue is that life would probably also use up the co2, still the dense atmosphere would help a lot in it self. 
 

[peadar1987]

19 hours ago, Abastro said:

Calculate the greenhouse effect of Venus, it should be bigger than 30. So the temperature could be still near the freezing point of water even if it is placed on 5AU. So, it's not that far.

It's just not something earthy atmosphere can give.

19 hours ago, Nathair said:

And what about the radiogenic heating I mentioned above? There's also residual accretion heating and heating from core formation (gravitational heat) to consider. In a youngish body (and depending upon composition) these could contribute a significant amount to the planet's heat budget.

So I actually messed up the equation a bit. The actual expected temperature is 130K. For a really dark body you can get that up to maybe 160K. CO₂ starts to sublimate at about 190K, so if you added some heat from impacts or large scale vulcanism or something, you could a actually get a reasonably thick CO₂ atmosphere. Pulling the fudge of adding massive amounts of tidal and radiogenic heating, and doubling the amount of energy reaching the planet (an extremely optimistic case) raises the expected temperature to 170K. Turns out that adding to the energy flux has pretty rapidly diminishing returns, due to the fourth power in the Stefan Boltzmann law. Increasing the temperature a little bit increases the amount lost to space by a heck of a lot.

If you had a REALLY thick CO₂ atmosphere you could probably get enough of a greenhouse effect to maintain extremely salty or ammonia-rich liquid water at the surface.

New numbers here if you want to play with them.