How salty is Laythe?

[ZenithRising]

I think you mean water has a higher heat capability, over 4 times as much as air, meaning it can absorb >4 times as many Joules or calories per gram. It also has a much higher heat conductivity, 24 times higher, and that makes it far, FAR, less useful at insulating.

Science!

Yes, that is what I meant, thank you. As I recall now, air is actually a pretty good insulator as far as they go.

It might just be me, but if we have a conclusive temperature reading, using a thermometer, wouldn't it be irrelevant what exactly caused this heat? Well, warmth actually, but im not going to fuzz about that. Sun, Jool, tidal friction, doesn't really matter because we have experimental data, right? The only temperature-related reading we don't have is an ocean reading, since all we have are temperatures programmed for atmosphere.

Since we only have access to atmospheric temperature readings, but we need the oceanic temperature to answer the salinity question, we need to come up with a good estimate for the oceanic temperature. To do that, we really need to know where the heat is coming from.

Also, the only thing we have to reference the density of the planets is gravitational attraction. Is it possible to leave everything the same and just assume that the gravitational constant G is 10 times what it is in our universe?

Hrmmmm, I'm not sure at the moment how to check the numbers on this, but perhaps someone else could? That seems like a reasonable hypothesis. Perhaps I'll look it up when I have a moment.

Edited August 15, 2013 by ZenithRising

[Aqua667]

Other idea: Since Laythe has a thinner atmosphere, it has less air pressure. Lower pressure lowers water's boiling point, shouldn't it also lower its melting point too? Lower melting point means that Laythe's water could be liquid at a lower temperature.

[Hannu]

Hmm... ill have to send a science mission over to Laythe then.

Also, the only thing we have to reference the density of the planets is gravitational attraction. Is it possible to leave everything the same and just assume that the gravitational constant G is 10 times what it is in our universe?

In very rough level maybe, but for example star's evolution is very sensitive to values of physical constants. I am not an expert in astrophysics, but I have understood that if you would change strong interaction just few percents stronger, stars would live just few years (or all hydrogen would have reacted immediately after big bang) or if it would be weaker, normal sized stars could not produce nuclear reactions at all. I do not know is gravity as sensitive as strong interaction, but it has very significant role in stellar physics too and probably changes in order of magnitude would lead to some very unpredictable physics.

In my opinion other interesting idea would be, that physics is just little different and at least some elements around number 120 are stable (or have half-life in geologic timescales) and abundant in Kerbin's world. It is theoretically predicted, that some of them would have densities about 40000 kg/m^3. Some of them may also be liquid in normal temperatures and we can imagine that Eve's violet liquid is some chemical compound of ultraheavy element, which evaporates and rains down and colors everything with violet color. But it is also just oversimple pseudoscientific idea for gaming purposes. If you change some assumption in physics, even very small amount, all predictions of all theories change in very unpredictable and sometimes very dramatically ways.

[Hannu]

Other idea: Since Laythe has a thinner atmosphere, it has less air pressure. Lower pressure lowers water's boiling point, shouldn't it also lower its melting point too? Lower melting point means that Laythe's water could be liquid at a lower temperature.

No. Very high pressures (some tens of atms) can lower water's melting point significantly but between 10 bar and vacuum it is practically constant. But how about some (fictional) extremely efficient greenhouse gas in Laythe's atmosphere, which keeps temperatures near 270 K.

[ZenithRising]

But how about some (fictional) extremely efficient greenhouse gas in Laythe's atmosphere, which keeps temperatures near 270 K.

I think if we're going to to try and seriously get a semi-conclusive answer, we'll need to assume that physics in KSP works as close to real world physics as possible. Otherwise we'll just be speculating endlessly. Not that there is anything wrong with that, but personally I'm really excited to gather some evidence, crunch some numbers, and come to some conclusions.

I think our best bet for this purpose is to assume that all the elements involved are analogous to our own, but with 10x gravity (putting the problems that creates with star formation aside for now).

[lewille]

Science!

Since we only have access to atmospheric temperature readings, but we need the oceanic temperature to answer the salinity question, we need to come up with a good estimate for the oceanic temperature. To do that, we really need to know where the heat is coming from.

What about geological activity? Even oceanic (as there does not look like there are much volcanoes at the surface)?

Would that be enough to raise the temperature enough to have liquid water?

[Spyritdragon]

Some of them may also be liquid in normal temperatures and we can imagine that Eve's violet liquid is some chemical compound of ultraheavy element, which evaporates and rains down and colors everything with violet color.

If the extra mass would be there, that would also mean that whatever craft you splash down in Eve's oceans, almost all of it would float at the surface rather that staying partially submerged.

What about geological activity? Even oceanic (as there does not look like there are much volcanoes at the surface)?

Would that be enough to raise the temperature enough to have liquid water?

I think developers have mentioned that Laythe would be much more volcanic in a later update.

[Hannu]

If the extra mass would be there, that would also mean that whatever craft you splash down in Eve's oceans, almost all of it would float at the surface rather that staying partially submerged.

It is true, but I think that any imaginable explanations has some conflict to real physics. For example propellants' densities are 5000 kg/m^3. If liquid in Kerbin's oceans was water, half filled tanks should sink, but in game they float and can even carry some load.

I think developers have mentioned that Laythe would be much more volcanic in a later update.

I think if we're going to to try and seriously get a semi-conclusive answer, we'll need to assume that physics in KSP works as close to real world physics as possible. Otherwise we'll just be speculating endlessly. Not that there is anything wrong with that, but personally I'm really excited to gather some evidence, crunch some numbers, and come to some conclusions.

I think our best bet for this purpose is to assume that all the elements involved are analogous to our own, but with 10x gravity (putting the problems that creates with star formation aside for now).

Yes, but if we assume normal physics except 10 times larger gravitational constant, Jool's moons (and every other planet too) are far too small to have large scale geologic activity due to internal heat. And on the other hand Laythe have exactly circular, non-inclined and tidal locked orbit so that Jool's gravity does not change as a function of time. So there can not be tidal heating from Jool. Tylo and Vall cause some effects (or not, if we are too exact, because in KSP gravity has range limited to SOI), but probably too small to produce large scale volcanic activity. In our solar system medium sized Saturn's moons (for example Enceladus) have some cryovolcanic phenomena due to tidal energy, but temperatures are at least 100 C below water's freezing. Even if we take into account possible salinity and atmospheric greenhouse effect, it needs quite exotic explanations. Just assuming anomalous gravity constant is not enough.

[lajoswinkler]

It seems there's nothing to heat up Laythe, so the temperatures can not be accounted for, but the oceans can stay liquid even at mentioned low temperatures. There are other salts in existence, not just sodium chloride. Calcium chloride makes this pond stay liquid even below -30 °C.

Ammonia is far less abundant on solid objects in the universe than sodium/calcium chloride because of its volatility and the fact it's a gas in a solution. Brine constituents are likely to stay in one place for a long time because they aren't volatile and can be washed into the sea.

You need to remember that this is a game in alpha state of development.

[ZenithRising]

Success!

All right geeky Kerbonauts, I have successfully launched a science mission to Laythe (and Duna and Eve), and I have data to share. It actually clears up the question of Laythe's salinity pretty well I think. Let's get started!

The Mission:

I built Pandora I, a deep space probe with 7 identical detachable probe landers. Each lander weighed less than a ton, was fitted with every scientific instrument available, a parachute, and about 1000 delta-v worth of thrust and fuel. The plan was to launch from Kerbin, do a fly-by of Duna where I could drop off the first pair of probes and then slingshot my way on to Jool.

I reached Duna easily and detached the first pair of probes. Using their rockets, one was aligned for a temperate intercept path, and another a polar intercept path. It took a number of save reloads to get them landed on Duna with the thin atmosphere and those spindly probe struts, but eventually I did get them both down safely, and returning data. As a bonus I flew by some sort of crazy Mt. Doom on Duna's north pole.

Now unfortunately my gravity slingshot was terrible, and I ran out of fuel trying to normalize my orbit around Jool. Mission aborted.

Pandora II featured slightly more fuel, a slightly lighter payload and somewhat better flying. It got depressing close to Laythe, but due to an eccentric orbit around Jool was unable to actually reach her SoC. Mission aborted.

Finally, Pandora III was launched, this time with twice the fuel.

This mission attempted to slingshot around Eve, and dropped a couple of probes off on the way, which landed easily in the thick atmosphere. The slingshot was mediocre, basically just getting back the delta-v I lost going to Eve, but with the extra fuel I made it to Laythe, established a ~45° orbit, and began dropping off probes.

The probe landings required some reloads, but were all successful. Shifting Pandora III's orbit from 45° all the way to a polar orbit allowed me to establish landing sites at a variety of latitudes and altitudes around Laythe, both on the shoreline, and far inland (or as inland as you can get on Laythe). Also, I got one probe right on the little island in the middle of that huge impact crater. Effing A.

All of the exact data I collected can be found on a google spreadsheet here if people are interested: https://docs.google.com/spreadsheet/ccc?key=0AuvW-Ya0mDJDdFpXbHpweHhWd1o1azFiY3I3MXR5RlE#gid=0

General Things I Learned:

1. Time of year, time of day, and latitude do not matter at all for determining temperature in Kerbal Space Program. This was born out by all nine of my probes on three different bodies. For the purposes of crunching numbers and doing science on KSP celestial bodies, we should probably assume that the temperature readings then are a general average of all times of day, seasons, and latitudes.

2. Altitude and/or barometric pressure do matter for determining temperature in KSP. The higher and thinner the atmosphere, the lower the temperature. This was also confirmed by all nine probes. In fact, the correlation was strong enough across all three bodies that the formula "t = 48p - 34", where 't' is temperature, and 'p' is barometric pressure, will yield reasonably accurate answers on all bodies (within about %5).

3. There is a small glitch with the in-game thermometer when switching focus to a ship. For whatever reason, when you switch the thermometer always starts at 0°, and then begins to rise or fall to the actual temperature. The speed of the rise/fall is exponential, beginning fast, and slowing as it gets closer to the proper number. The time this takes seems to take about 60 seconds, regardless of whether the temp is 2° or 200°. So, when reading temperature data, make sure you always wait at least minute after switching craft focus to record the number.

Things I Learned About Laythe:

1. It's warm there! Relatively at least. While the temperature does drop below freezing at higher altitudes, anything below about 600m is above freezing. In fact, my warmest reading (pictured below), taken from an altitude of just 10m and a barometric pressure of 0.7979, was a balmy 4.59°. That's jacket weather! Ironically, this reading came from atop Laythe's northern ice cap. Latitude definitely doesn't affect temperature in KSP!

In Conclusion:

Due to Laythe's relatively warm temperatures at sea level, I cannot conclude much definitively about the salinity levels of her oceans. I can however conclude that no exotic substances or compositions are necessary to explain Laythe's largely liquid surface. It could be fresh water and we would still expect it to be mostly liquid. Given that information, my assumption is, lacking evidence to contrary, that the salinity levels are similar to those on both Kerbin and Earth.

Edited September 11, 2013 by ZenithRising

[halbert5150]

The thing I find amazing about this debate in this thread is that the very same debate raged for 30 years in regards to Titan. Obviously were not scientists with PHD's and so forth but the parallels are very interesting.

[Holo]

Well, that settles it. Laythe is being warmed somehow, now the only question is how.

[Traches]

How accurately is buoyancy modeled in the game? You could determine laythe's oceans' density with an empty fuel tank floating vertically-- put low-mass parts at equal intervals down the side to measure where the waterline is, work out the volume displaced, and divide the mass of the tank by that. That information would certainly allow you differentiate between ammonia and water, and if you make the assumption that it is in fact salt water you could estimate its salinity.

[Temstar]

Correct me if I'm wrong, but as pointed out Laythe doesn't have tides (at least not from Jool) because it's already tidal locked to Jool. So yes Jool's gravity still pulls on Laythe and the surface water layer will deform into a ellipsoid shape with two tidal bulges. But since these two bulges are stationary on the planet's surface instead of moving around like the moon-induced bulges on Earth there is actually no rise and fall of tides on Laythe.

Since the tidal bulges are not moving, no mechanical work is being done and there is no conversion of Laythe's angular momentum into heat via tidal heating. In fact in the dim past when Laythe was not tidal locked to Jool it would have had tidal heating from the tidal bulges moving around on the surface. The fact that Laythe is tidal locked to Jool nowadays is precisely because Laythe has lost enough angular momentum via tidal heating that it's rotation has slowed down to match it's orbital period and therefore no further energy can be extracted into heat the planet via tidal heating?

Of course other moons around Jool would pull on Laythe too, but surely those attractions are nothing compared to the overwhelming gravity of Jool itself and therefore don't deform the bulge enough to provide much heating effect?

[ZenithRising]

Is Laythe's orbit perfectly circular? An elliptical orbit would create some tidal forces, though not as much as rotation.

Also, if solar panels around Jool get about 50% power, we can probably assume that with KSP physics Laythe gets about half the heat from Kerbol that Kerbin does, and that solar radiation could easily be the heat source.

[CorruptDB]

Correct me if I'm wrong, but as pointed out Laythe doesn't have tides (at least not from Jool) because it's already tidal locked to Jool. So yes Jool's gravity still pulls on Laythe and the surface water layer will deform into a ellipsoid shape with two tidal bulges. But since these two bulges are stationary on the planet's surface instead of moving around like the moon-induced bulges on Earth there is actually no rise and fall of tides on Laythe.

Since the tidal bulges are not moving, no mechanical work is being done and there is no conversion of Laythe's angular momentum into heat via tidal heating. In fact in the dim past when Laythe was not tidal locked to Jool it would have had tidal heating from the tidal bulges moving around on the surface. The fact that Laythe is tidal locked to Jool nowadays is precisely because Laythe has lost enough angular momentum via tidal heating that it's rotation has slowed down to match it's orbital period and therefore no further energy can be extracted into heat the planet via tidal heating?

Of course other moons around Jool would pull on Laythe too, but surely those attractions are nothing compared to the overwhelming gravity of Jool itself and therefore don't deform the bulge enough to provide much heating effect?

Well, in the case of Jupiter's moon Io, the Laplace resonance combined with its eccentric orbit results in tidal heating. Laythe doesn't have any eccentricity but it is in a Laplace resonance with Vail and Tylo so maybe that is what is heating it.

[loknar]

Yes it is salty. But it is also sweet and spicy, so it compensates.

[liweih]

Will it be Vodka? XD

[Dooz]

Sence i guess i am not taking the ksp thermometer celsius sounds more acurate fahrenheit on the ksp thermometer most likey water because laythe seems to be 3 degrees celsius and tidal forces from jool warms laythe so water

[loknar]

Yes the oceans are Vodka. The Kerbals are very confortable in this environment because their DNA is close to olives. Their suits only need a twist of lemon.

[Brotoro]

Correct me if I'm wrong, but as pointed out Laythe doesn't have tides (at least not from Jool) because it's already tidal locked to Jool. So yes Jool's gravity still pulls on Laythe and the surface water layer will deform into a ellipsoid shape with two tidal bulges. But since these two bulges are stationary on the planet's surface instead of moving around like the moon-induced bulges on Earth there is actually no rise and fall of tides on Laythe.

Since the tidal bulges are not moving, no mechanical work is being done and there is no conversion of Laythe's angular momentum into heat via tidal heating. In fact in the dim past when Laythe was not tidal locked to Jool it would have had tidal heating from the tidal bulges moving around on the surface. The fact that Laythe is tidal locked to Jool nowadays is precisely because Laythe has lost enough angular momentum via tidal heating that it's rotation has slowed down to match it's orbital period and therefore no further energy can be extracted into heat the planet via tidal heating?

Of course other moons around Jool would pull on Laythe too, but surely those attractions are nothing compared to the overwhelming gravity of Jool itself and therefore don't deform the bulge enough to provide much heating effect?

Laythe is tidally locked to Jool, yes, so the tidal bulges produced by Jool stay in the same locations. But Laythe interacts with Vall and Tylo in the same way that Io, Europa, and Ganymede interact. These other moons will cause the eccentricity of Laythe's orbit to oscillate over time, and the orbit sizes to slowly change...so the synchronous rotations of the moons would get out of sync...and it is Jool (or Jupiter) constantly wrestling the moons back toward sync that causes the heating.