I've still got some wonky worlds in my sector

[Stattick]

X416000, temperate.

So, it's small. It has virtually no atmosphere. Yet it has almost Earthlike amounts of water? I could understand if it was a frozen world, but on a temperate world, that would be liquid water. Why wouldn't the water either evaporate to maintain something resembling an atmosphere, or evaporate out into space if the gravity wouldn't be strong enough to hold an atmosphere?

Now, my knowledge of planetary science is limited and dubious at best, so maybe this make some sort of sense that I'm not seeing. Or maybe it's just broken. Who knows something about this sort of thing that feels like schooling this ignorant knucklehead?

 

[Elysianknight]

Hydrographics is 2d6-7, plus 4 for size with a minus 4 for atmo 1. Therefore the max possible is 5, so somewhere your maths went wrong?
Also not sure if you get the -6 for roasting day temps (from atmo 1 mods)

 

[Stattick]

Hydrographics is 2d6-7, plus 4 for size with a minus 4 for atmo 1. Therefore the max possible is 5, so somewhere your maths went wrong?
Also not sure if you get the -6 for roasting day temps (from atmo 1 mods)

"Somewhere my maths went wrong" wouldn't surprise me a bit. I "rolled up" the sector with a spreadsheet I designed, which may have possibly had some errors in it. I rolled it up with the quickstart rules. Then, after getting the corebook, retroactively applied as much of the changed rules as possible. If I wasn't already playing in this sector, I'd have just started over from scratch... A 5 would make a little more sense, while even lower would make more.

Perhaps the "atmosphere" is mostly valley hugging water vapor in the day that settles to turn to frost at night? The "oceans" would freeze, at least partially at the surface, at night as well, and then thaw in the day. The world would be constantly loosing water to evaporation that could be "blown" away by the solar wind. Yet, with the insulating power of the water, I could possibly imagine stuff living in the sea.

 

[Daneel Olivaw]

Maybe most of the water is in oceans below the surface, heated by tidal forces from a parent planet (as in Jupiter's effect on Europa) and "temperate" refers to the subsurface climate.

 

[Gee4orce]

The world gen rules definitely throw up some real oddities - but that's no bad thing because half the fun is trying to interpret them. If they were completely realistic then, let's face it, almost all worlds rolled up would be very minor variations of what we see in the solar system (because that's still really all we have to base our ideas on - the extreme extra-solar worlds that have been discovered so far are really extreme oddities). I suppose the key saving grace of the system is that its' supposed to represent the most habitable planet in the system, not your run-of the mill planetary body.

As for your world - the average temperature might be temperate - but taking mars as inspiration, the hydrographics UPP probably means that all that water is locked up in frozen polar / tropical ice caps, where it's considerably colder.

 

[EDG]

That is a problem because the pressures at which Trace atm are defined (0.001 to 0.09 atms) severely restrict the conditions in which liquid water is allowed to exist. At the low end, it basically can't exist on the surface - it goes straight from solid to gas state (as is the case on most of Mars). At the high end, liquid water is stable up to about 320K (50°C ish). But also, the thinner the atmosphere, the more extreme the day/night temperatures will be because the atmosphere won't be able to trap and redistribute the heat.

TBH I don't think it makes a lot of sense as it stands - if all that water is liquid then the atmosphere should be thicker, and if all that water is solid then it can't really be "temperate". So I'd suggest changing the temperature to Cold or Freezing (in which case it'd be a world in the middle or outer zones of the system).

 

[Maedhros]

Is it possible to have Temperate conditions on an ATM 1 world?

ATM 0 or 1 worlds have "wildly fluctuating" temperatures between boiling and freezing...

 

[EDG]

Is it possible to have Temperate conditions on an ATM 1 world?

ATM 0 or 1 worlds have "wildly fluctuating" temperatures between boiling and freezing...

Atm 0 worlds will (if they're in or within the habitable zone). Atm 1 worlds will also have the extreme fluctuations (between day and night sides) if they're at the low end of the pressure range. At the higher end of the Trace range the temperature extremes are a little more moderated by the thickness of the atmosphere.

 

[Rikki Tikki Traveller]

Temperate is the AVERAGE temperature. The Moon is Temperate: Boiling during the day and Freezing at night, perfectly Temperate.

Don't let the Temperature fool you. Also, read the section in the TMB about Atm 0 and 1 with regards to temperature.

And you are right, the rules don't account for temperture in the other rolls. A temperate world with a Trace atmosphere will not have water (it might have a bit of ice at the poles, but that is it). You are going to have to hand massage the numbers.

Either raise the atm code or lower the hydro code or lower the temperature. Your choice.

 

[Supergamera]

You might have something other than pure water for your hydro content. Water with a high salt content, or maybe an ocean of ethylene glycol, might be more stable on such a planet, and help to moderate the temperature without freezing or boiling off.

 

[kristof65]

Is it possible this is a world in transition?

Lots of underground ice that has just recently been exposed, and is gassing off, leading to a thin atmsophere?

I don't know if that's even possible, just throwing it out there.

 

[Stattick]

You are going to have to hand massage the numbers.

Either raise the atm code or lower the hydro code or lower the temperature. Your choice.

Alrighty, no problem. I just wanted to make sure that this wasn't a workable planet and I wasn't seeing it. I'll have to remember to highlight it and the other similar ones for alteration (I found at least 2 more that were virtually identicle). When you know how to use it, conditional formatting in Excel is your friend - just define what you want to find, and turn it red in that wall of numbers.

 

[Maedhros]

You might have something other than pure water for your hydro content. Water with a high salt content, or maybe an ocean of ethylene glycol, might be more stable on such a planet, and help to moderate the temperature without freezing or boiling off.

Introducing solutes into water will decrease the melting/vaporization point, so that might not help.

Binding the water in hydrous minerals (e.g. brucite Mg(OH)2, Gypsum CaSO4*4H20, various clays/micas, etc.) might help if you view Hydrosphere as mole fraction

What about having a meters-thick layer of hydrocarbon on top of the water? Would that prevent excessive sublimation/evaporation?

 

[EDG]

There isn't really any liquid stable at those pressures that could form naturally and be stable on the surface in big enough volume in that atmosphere (for one thing, liquid oceans would make their own atmosphere as molecules evaporated from the surface).

 

[Stattick]

I'll just make 'em frozen worlds.


I've been thinking about it, and I think the problem stems from the temp rating. If there wasn't a temp rating that said that this was a "temperate" world, there wouldn't be a problem with the hydrology. The temp system looks/feels like it was just sort of tacked on at the last minute...

There is a listing in there for modifiers to temp based on whether a planet is at the hot or cold edge of a star's habitable zone, yet no mechanic to actually determine the planet's position in the habitable zone. In other words, it's a mechanic that basically says, "Yeah, go ahead and hand wave it if you want." :roll:

As if I needed to get permission to change it in the first place. :lol:

 

[EDG]

Actually if you look at the playtest version (at least the 3.2 one, which is what I have a copy of here) they did have a load of modifiers to temperature based on the orbital zone. But that's not in the final version (beyond a relatively slight DM +/- 4 tacked on at the end). I guess they thought that adding orbits and stuff would complicate the worldgen (especially given nothing else mentioned orbits, and there was no way to generate the orbits either).

 

[Stattick]

Ok...

So what do others generally do with Earthlike worlds that rolled up as "uninhabited"?

I'd think that those would be the first worlds colonized. Although I suppose that there could be native life there that makes the world too inhospitable to humans (like landing back in the Jurassic for instance).


On the other hand, if the life is too inhospitable (assuming it's not lethal microbs or bugs), I think I'd just engineer an extinction level event to kill off the nasty megafauna, let's say a comet nudged in the right way, and then set up a colony a couple of generations later.

 

[Vile]

Maybe the DNA just twists the wrong way?

 

[kristof65]

So what do others generally do with Earthlike worlds that rolled up as "uninhabited"?

Various things that can be done:

- Disappearing colonies (Think Roanoke VA). I think captainjack has a write up for such a world around here.

- some sort of electromagnetic interference/radiation that makes the planet inhospitable to technology and/or long term inhabitance

- recently completed terraforming, it won't be long before the world is opened up to colonization.

- "private" world used by nobility, corporations, etc.

- primitive near-sentient species

- periodic solar events wipe out life on the planet every 10 to 200 years or so. Local fauna and flora have adapted, and it "re-populates" quickly.

- An Ancient device buried in the core slowly drives sentient life crazy if they stay too long.


Keep in mind that while a world may be "officially" earth like and unihabited, the reality might be quite different. Think of the Firefly movie Serenity where the world has been terraformed, but it's habitability is covered up to cover up a greater crime.

 

[Supergamera]

So what do others generally do with Earthlike worlds that rolled up as "uninhabited"?

A few examples from other fiction:

- Planet is irradiated from the extinction-causing war caused by the previous residents.

- Lousy weather makes it unpleasant or dangerous, including
- Rains for 7 years straight
- Seasonal, constant hurricane-strength winds
- Occasional megastorms

- Unpleasant ecosystem, like one based on regular planet-sweeping firestorms.

- Planet is in a highly eccentric orbit - it's nice now, but will be too hot/cold in another 100 years.