Author Topic: Water and Terrain in Eccentric Orbits  (Read 1155 times)

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Offline Steve Walmsley (OP)

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Re: Water and Terrain in Eccentric Orbits
« Reply #15 on: September 17, 2021, 04:27:39 AM »
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.
 

Offline serger

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Re: Water and Terrain in Eccentric Orbits
« Reply #16 on: September 17, 2021, 05:35:14 AM »
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.
 

Offline db48x

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Re: Water and Terrain in Eccentric Orbits
« Reply #17 on: September 17, 2021, 12:06:37 PM »
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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Online nuclearslurpee

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Re: Water and Terrain in Eccentric Orbits
« Reply #18 on: September 17, 2021, 12:37:53 PM »
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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Offline Migi

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Re: Water and Terrain in Eccentric Orbits
« Reply #19 on: September 17, 2021, 10:30:22 PM »
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.
 

Offline Garfunkel

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Re: Water and Terrain in Eccentric Orbits
« Reply #20 on: September 18, 2021, 02:34:22 AM »
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.
 

Offline nakorkren

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Re: Water and Terrain in Eccentric Orbits
« Reply #21 on: September 18, 2021, 07:30:43 AM »
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.
 

Offline Blogaugis

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Re: Water and Terrain in Eccentric Orbits
« Reply #22 on: September 20, 2021, 03:12:20 PM »
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...