Aurora 4x
C# Aurora => C# Mechanics => Topic started by: Steve Walmsley on September 16, 2021, 07:15:58 AM
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I'm about six years in my test campaign for v2.00 and I've discovered 48 systems, which means I have already encountered several challenges in dealing with eccentric orbits.
As an example, I've found what would looks like an amazing planet. Great mineral resources and a diameter of only 3200 km, making it easy to terraform. However, it has an eccentricity of 0.61 and it orbits between 6m and 26m km from the M3-V primary. So far I have added 0.37 atm of atmosphere, including 0.06 atm of water vapour.
Alexandria-A II Survey Report
Duranium: 2,320,076 1.00
Neutronium: 21,670 0.50
Tritanium: 5,921 0.90
Boronide: 1,584,327 0.80
Mercassium: 8,861 0.90
Vendarite: 1,618,984 1.00
Uridium: 375,773 0.90
Corundium: 1,380,521 0.60
Gallicite: 1,446,752 0.70
The temperature ranges from -78C to 122C over a 23 day orbit, which has two effects. Firstly, the water is frozen, liquid and vapour at different points of the orbit, with a knock-on impact on albedo and water-related colony cost. Secondly, the dominant terrain changes multiple times per orbit.
Given the above, I am wondering whether to change hydrosphere type and dominant terrain to be fixed for the entire orbit unless the environment changes via without terraforming. If I do make them fixed, I also need to decide the parameters. For example, should the dominant terrain be possible across the whole temperature range, or based on the average temperature? If average, should that be based on a straight (min/max) / 2 or take into account that planets will spend more time at the min temp due to orbital speed.
Hydrosphere would have to be based on some sort of average because there is no single state that could exist across all possible temperatures. Or maybe I invent a fourth state for water, that can be applied in that case and has its own effect on colony cost and albedo.
Also, does the year make a difference. This planet has an orbital period of 23 days, but others could be years or decades.
Finally, leaving things as they are is also a reasonable option. In this case, colony cost would reach 2.00 at certain points in the orbit due to the water evaporating. I would have to bring the temperate range down, accepting a lower temp at the minimum to bring the max temp within the liquid water range. Terrain changing regularly only affects ground combat and surface-to-orbit. Invasions would have to be staged in the best 'season' for the attackers.
I'm laying all this out to spark discussion :)
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Would it make sense to add some inertia to the hydrosphere type or have larger hydrospheres provide some inertia to planet temperatures?
It's probably not very realistic to have planetary sized bodies of water swap from frozen solid to steam and then back again in a matter of days.
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Maybe make it possible to spacemaster/technology mumbo-jumbo the orbit into more stable one?
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Would it make sense to add some inertia to the hydrosphere type or have larger hydrospheres provide some inertia to planet temperatures?
It's probably not very realistic to have planetary sized bodies of water swap from frozen solid to steam and then back again in a matter of days.
Interesting idea. In the past, the change from liquid to vapour was instant because it was always the result of terraforming and therefore likely to be permanent. Maybe the change should be gradual in the same way as condensing (0.1 atm per year). That would solve the problem of drastic changes in short orbits while leaving the option of different conditions in long orbits.
Liquid to ice and back is less of an issue because it only affects albedo and doesn't introduce a sudden 2.0 colony cost (and I already include albedo changes in the min/max temperature and min/max colony costs). I could perhaps track the percentage of water that is frozen, rather than having separate states, but in reality the water to ice process happens quite quickly so probably not worth it.
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Would it make sense to add some inertia to the hydrosphere type or have larger hydrospheres provide some inertia to planet temperatures?
It's probably not very realistic to have planetary sized bodies of water swap from frozen solid to steam and then back again in a matter of days.
I think this is a good solution, having a sort of inertia for the hydrosphere and climate type which can be tied to the body size. This seems like an approach that is not too difficult to understand for players but allows slower transitions (a planet with a 100-year orbit that changes its climate over those 100 years would be cool!) but not unrealistically rapid shifting of the terrain class every five days. After all, flora and fauna take time to grow, live, and die, 23 days is not enough time for such an ecosystem to adapt but 100 year cycles may be, certainly some interesting life forms would evolve under such conditions.
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Terraformers/Tugs that can change planetary orbit! :)
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I think it's very strange to have dominant terrains changing from Taiga/Forested/Jungle to Desert and so on every 23 days or even less (no type of forest is capable to rise so fast!), and there will be no arbitrary point for every pair of terrains transition time. So I think the only way with eccentric orbits is to unite those terrain types, which differences are only biological. More so that I think there are strange things, too, that:
1. Some strange significant difficulties with biome for TN-equipped armies capable of garrisoning every airless frozen or venusian stone-burning hell without tension;
2. We can choose planetary dominant terrain based on biome types, nearly equally presented in Earth (and really there are more tundras, savannas, steppes and deserts on Earth comparing to temperate forests, and the only thing Temperate Forest is common - in the past - it's for those countries our technological civilization was born in historically).
So I think Terrain Type might reflect only geological types like [Flat, Rifty, Mountainous, Volcanic] with a (potentially changeable) type of Oceanic where there is nearly no dry land to make any of those types relevant.
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As for terrain, it'd make sense if the planet just kept one based on it's average temperature. It makes sense to assume that the landscape has come to some sort of stable state after undergoing the same cycle for millenia. As for which average, just pick one you're already displaying on the system view so you don't have to display another one :-)
Counterpoint: On a planet with long cycles it'd make sense if the vegetation changed enough to turn a rift valley into a jungle rift valley for a decade or two and then died off again as the long winter approaches. But one can argue that using the mintemp+maxtemp/2 average instead of the "longer in the cold part of the orbit" average favors higher temps and therefore the more vegetated terrains, representing such cases with temporary vegetation better.
The main argument for not changing the terrain is not introducing more complexity than is needed or easily understandable. For one key planet having such a mechanic may be neat, but for a hundred other rocks that change some part of themselves over the course of their orbit you're probably just going to sigh that this weird interaction threw you a wrench in the works again.
The water changes on your planet in particular are egregious, and I'm also in favor of keeping them in one state. We already have tide-locked planets that may have several states of water on them at the same time, and much like with the terrain, it stands to be reasoned that there is some stable and predictable water cycle the planet has developed.
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As for vegetation... There is no option to have any sort of soil on anoxic planet. No life - no sod - no soil. There will be plenty of rocks, sand and mineral dust, yet to have a soil or even clay (except on oceanic abyssal flat) - you need at least thousands of years of ubiquitous terrestrial vegetation.
So I think it will be cool to have this feature: a boolean field Soil Layer, possible for the same planets that have oxygen, mandatory for homeworld planets, can be erazed with backing (I'd say average surface temp 1000C), cannot be restored during playtime, mandatory for <1.50 CC.
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As for vegetation... There is no option to have any sort of soil on anoxic planet. No life - no sod - no soil. There will be plenty of rocks, sand and mineral dust, yet to have a soil or even clay (except on oceanic abyssal flat) - you need at least thousands of years of ubiquitous terrestrial vegetation.
So I think it will be cool to have this feature: a boolean field Soil Layer, possible for the same planets that have oxygen, mandatory for homeworld planets, can be erazed with backing (I'd say average surface temp 1000C), cannot be restored during playtime, mandatory for <1.50 CC.
Two things: If you can't create a soil layer, how could you ever fully terraform Mars and other planets?
And what about alien biologies? Even if they'd be incompatible with human/Earth biology, large alien plants could still provide the cover that the terrain modifiers represent.
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Liquid to ice and back is less of an issue because it only affects albedo and doesn't introduce a sudden 2.0 colony cost (and I already include albedo changes in the min/max temperature and min/max colony costs). I could perhaps track the percentage of water that is frozen, rather than having separate states, but in reality the water to ice process happens quite quickly so probably not worth it.
Does this mean adding ice will lower albedo in 1.14/2.0?
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Liquid to ice and back is less of an issue because it only affects albedo and doesn't introduce a sudden 2.0 colony cost (and I already include albedo changes in the min/max temperature and min/max colony costs). I could perhaps track the percentage of water that is frozen, rather than having separate states, but in reality the water to ice process happens quite quickly so probably not worth it.
Does this mean adding ice will lower albedo in 1.14/2.0?
Water to turning to ice and vice versa already changes albedo in v1.13.
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Does this mean adding ice will lower albedo in 1.14/2.0?
Water to turning to ice and vice versa already changes albedo in v1.13.
I was refering to
Yes, although I probably should change it so that adding ice reduces Albedo.
which I haven't seen mentioned in any of the Changes Lists.
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I don't know the exact math, but shouldn't atmospheric pressure have an insulatory effect regulating the extreme temperature radiation. I know on a daily scale this is important in comparing min/max day/night temperatures between earth, Mars and mercury, and I would assume the effect would be present though likely not as strong for longer time scales for orbital eccentricity.
Could maybe even add another -isium type gas that reduces temperature variation.
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What about just adding a new environment/hydrosphere for sufficiently eccentric planets? IE on that planet instead of swapping back and forth between them it would just say Environment: Extreme Variations and Hydrosphere: Seasonal?
My concern with giving inertia to the hydrosphere is that it might complicate terraforming. Hydrosphere changes albedo, which normally isn't an issue since it shifts instantly, so if you're adding greenhouse gases to a planet at some point you'll get a message the hydrosphere has melted and that bumps the temperature up further. But if there's a delay, that could mean terraforming too quickly would result in you getting the planet up to a pleasant temperature, then the hydrosphere melts and the temperature jumps past the high end of tolerance.
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What about just adding a new environment/hydrosphere for sufficiently eccentric planets? IE on that planet instead of swapping back and forth between them it would just say Environment: Extreme Variations and Hydrosphere: Seasonal?
My concern with giving inertia to the hydrosphere is that it might complicate terraforming. Hydrosphere changes albedo, which normally isn't an issue since it shifts instantly, so if you're adding greenhouse gases to a planet at some point you'll get a message the hydrosphere has melted and that bumps the temperature up further. But if there's a delay, that could mean terraforming too quickly would result in you getting the planet up to a pleasant temperature, then the hydrosphere melts and the temperature jumps past the high end of tolerance.
If I add inertia it would only be between liquid and vapour. See my answer a few posts above on this topic.
I been considering a different hydrosphere state, but I think there are too many variations. For example, a planet that is mainly liquid that loses it during a small portion of the orbit is very different from a planet that only has liquid for a small portion and both are different from the planet above with all three states within a few days.
At the moment I am leaning toward adding the same limit on evaporation as exists on condensation (0.1 atm per year), plus making the dominant terrain fixed if the orbital period is six months or less (unless terraformed). That dominant terrain would be based on all possible environmental conditions during the orbit.
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Two things: If you can't create a soil layer, how could you ever fully terraform Mars and other planets?
Mars - never fully, just to 1.5 point or smth like this (free to live in open, yet no open planetary scape agriculture).
Some other planets with their own long-lasting life - as usual, and yep, these planets with life and soil might be very, very, very valuable ones.
And what about alien biologies? Even if they'd be incompatible with human/Earth biology, large alien plants could still provide the cover that the terrain modifiers represent.
I don't think a plant can provide sufficient cover against TN-tech weapons and sensors. This thing is just torturing me with disbelieve.
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Would it make sense to add some inertia to the hydrosphere type or have larger hydrospheres provide some inertia to planet temperatures?
It's probably not very realistic to have planetary sized bodies of water swap from frozen solid to steam and then back again in a matter of days.
Interesting idea. In the past, the change from liquid to vapour was instant because it was always the result of terraforming and therefore likely to be permanent. Maybe the change should be gradual in the same way as condensing (0.1 atm per year). That would solve the problem of drastic changes in short orbits while leaving the option of different conditions in long orbits.
Liquid to ice and back is less of an issue because it only affects albedo and doesn't introduce a sudden 2.0 colony cost (and I already include albedo changes in the min/max temperature and min/max colony costs). I could perhaps track the percentage of water that is frozen, rather than having separate states, but in reality the water to ice process happens quite quickly so probably not worth it.
Temperature changes could be gradual as well. Planets heat up because radiation from their star hits them, and heat is simultaneously escaping the planet by radiating away. If more heat is radiating away than is radiating in, then the planet is cooling, otherwise it is heating up. One interesting quirk is that the amount of radiation emitted is proportional to the fourth power of the temperature, so hot objects radiate away heat faster than cold objects, all else being equal. (On the other hand, emission doesn’t really become an efficient process until you hot enough to glow in visible light).
With some interia in the temperature, the planet in your example would probably have a narrower range of temperatures. Especially since it spends a lot less time near the periapse, and more near the apoapse.
Perhaps For extra fun, you could actually implement the single–layer model, where the ground absorbs part of the incoming radiation and reflects the rest (due to albedo), the ground emits radiation, part of which is absorbed by the atmosphere. The atmosphere also emits radiation, some of which goes into space and some of which is reabsorbed by the ground. Normally you solve this for an equilibrium condition, but with an elliptical orbit the numbers wouldn’t always balance. You would need to track the atmospheric temperature separately from the ground/hydrosphere temperature, which could be a lot of fun. Plus you would get to decide what temperature new gasses from the aether are brought in at when terraforming!
Another thing you could do is to take into account the latent heat of the hydrosphere as it freezes and melts. As you know, water that is freezing stays at 0℃ the whole time. The heat that is in the water is emitted to the surroundings, but instead of dropping the temperature of the water, this causes a phase change instead. Likewise, when melting the ice absorbs heat but the temperature does not go up. If that planet has any significant amount of water, it would buffer the temperature quite a lot: as the planet heats out towards the apoapsis, the temperature of the ground, the hydrosphere, and the atmosphere would begin to drop. The hydrosphere would begin to freeze, dumping heat into the atmosphere and helping it to stay near 0℃. Thus the colony cost would not go up right away.
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Another thing you could do is to take into account the latent heat of the hydrosphere as it freezes and melts. As you know, water that is freezing stays at 0℃ the whole time. The heat that is in the water is emitted to the surroundings, but instead of dropping the temperature of the water, this causes a phase change instead. Likewise, when melting the ice absorbs heat but the temperature does not go up. If that planet has any significant amount of water, it would buffer the temperature quite a lot: as the planet heats out towards the apoapsis, the temperature of the ground, the hydrosphere, and the atmosphere would begin to drop. The hydrosphere would begin to freeze, dumping heat into the atmosphere and helping it to stay near 0℃. Thus the colony cost would not go up right away.
I like this idea because it would make terraforming even more interesting on these eccentric-orbit planets, since we can also choose to add more than the 20% minimum hydrosphere to create a water/ice buffer against temperature changes to maintain colony cost at a desired value. Gameplay wise this would be a fun and immersive mechanic.
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I doubt there are many life forms which can survive such large changes in temperature, regardless of atmospheric composition, so you could start by excluding any forest/jungle type of terrain.
I don't see it being inherently problematic if it changes from a hot desert to a cold desert, but the sudden appearance and disappearance of mountains or jungles would be.
So maybe the solution could just to be having a hot, medium, and cold environment types and it switches between them, depending on whether it passes through the 100 and 0 degree marks?
As for temperature inertia, the planet core has a fixed (for game timescales at least) temperature which would provide some sort of buffer to temperatures falling too much and changing too quickly. However that might be a factor you don't want to start adding just for the sake of it.
As a final note, any infrastructure for the colonists would need to be adapted to both extreme heat and extreme cold, is it worth having a minimum 3.0 colony cost for this? Adapting a house or car to cold weather and hot weather normally involve rather different designs, so if you want to incorporate both features into the same design it will be less efficient.
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Hydrosphere and/or atmosphere acting as a buffer that delays changes sounds like a good compromise to me.
The main argument for not changing the terrain is not introducing more complexity than is needed or easily understandable. For one key planet having such a mechanic may be neat, but for a hundred other rocks that change some part of themselves over the course of their orbit you're probably just going to sigh that this weird interaction threw you a wrench in the works again.
But that only really matters for ground combat, not for normal colony operations so having 100 rocks with such changes doesn't really matter that much.
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The idea of thermal inertia from the hydrosphere is really neat and I believe will help temper (pardon the pun) the more extreme environmental behavior possible from eccentric orbits.
Actual implementation could be as simple as creating a maximum temperature change rate based on the size of the planet, hydrosphere percent, and any other factors Steve wants to include such as distance from the star and brightness of the star.
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At this rate, I think I prefer some capability to create artificial spacial bodies/planets, with a fairly stable environment conditions...
Maybe even artificial stars too...
Still, I think there needs to be 2 simultanous states on worlds:
biological state - the state of plants and other beings alive...
elevation state - basically, how (un)even the planet is.
Biological can be unstable with how these planets end up being heated on one end, and cool down on the other.
Elevation should be pretty stable - if it was mountainious, it should stay like that for quite a while.
So, in this way, it can be pretty much that you are fighting on flatlands, the question basically is whether it is all frozen here,
or is it a napalmed hellscape, or perhaps somewhere in between...
The only question remains regarding the formula, is how to evaluate the fighting efficiency - since we have 2 variables instead of 1...