Sysgen Topics*: Planets (day 6)

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Re: Sysgen Topics*: Planets (day 6)

Postby Cralis on Wed 26 Aug 2009 15:01

crucis wrote:
Cralis wrote:By request: Planet Types. Makes sense, no? I have them defined elsewhere (like the rules) but to make sense of these results I should have included them. So here they are!

I'm not going to repeat T, ST, G, V, H, B, or F because they are as defined in the ULTRA rules. Although currently H/F are the same as hot or frozen O1 worlds, and B is O2 worlds. (Hot, Frozen, Barren).


Actually, "currently" in Ultra, O1 = Cold and O3 = Hot, according to W6.06.


Blah, I used my notes. Probably a hold-over from Classic Starfire. But yeah, your right. I'll note it for the conversion.

crucis wrote:
cralis wrote:What's the real difference between Type A and Type K? Also, I don't see any Type K planets in the "DETERMINE FINAL PLANETARY TYPE" Tables. (And a tangential note on those tables, in the mass 1 planetary type subtable, there's a type O3 entry that I suspect needs fixing.)


I've read where "experts" think that such "desert planets" would be essentially uninhabitable for humans due to the lack of plant life to produce oxygen. And not that I'm outright asking for this, but you might want to think about how such "desert" planets are able to sustain their atmospheres (whatever its composition may be). After all, if you were to go dump a major population on such a world, might that population not place some rather severe demands on a very limited and potentially non-reproducing, critical life-sustaining factor.


That would be part of the rules. What you've mentioned is already considered, and the only O/N atmosphere would likely be if there were any bodies of water. The other types don't even require water to be present (although it would be, in small amounts, probably underground).

PS. The difference between A and K is the temperature. Type-A have normal earth-like temperatures but insufficient atmosphere. Type-K planets have sufficient atmosphere, but they are too hot.

crucis wrote:
cralis wrote:Type-N/SN: Ocean
These are Type-T or Type-ST worlds where the vast majority of the planet is covered with water (> 90%). These worlds will pretty much only have oxygen-based atmospheres simply because solar evaporation will create most of the atmosphere from the water.


Interesting. However, I think that you missed an opportunity, code-wise here... I suspect due to inertia. I edpect that you created the N/SN codes while the old O# codes still existed. However, now that H/B/F have replaced the O# codes, I would suggest using O and SO instead of N/SN, since "O for Ocean" is a solid mnemonic.


It has for years been generally accepted that "N" is an ocean world. I don't remember where I saw the proposed nomenclature - it was an international astronomy website - but I originally found it in a ST:NG technical manual and it had the address.

crucis wrote:
cralis wrote:Type-GI: Gas/Ice
These are Type-G planets that have a different chemical composition. These will have more noble gases and other gases than simply H/He, although H/He is usually still a big part of their atmosphere. Otherwise, other than color, these are pretty much the same.

Type-I: Ice
In this version the Type-I worlds are going to be Ice or Rock/Ice worlds like Pluto. They aren't as common, as most of what ULTRA calls Type-I will be Type-GI instead.


Exactly how is this version of a Type I world different from a Type F world? I see the Type F world as fitting this description to a "T".


Type-F worlds are entirely rocky. Type-I worlds are entirely or mostly ices, probably methane, ammonia, carbon monoxide, along with water ice. Similar to Triton, except more ice less rock. Type-Is were speculated way back when they thought Pluto (and other KBOs) were thought to be mostly water ice, methane ice, ammonia ice, etc., with a very small core. However, more recently they are beginning to think it is mostly water ice with a small radioactive rocky core. Either way in about 6 years we'll get some solid evidence.

crucis wrote:BTW, a potentially interesting planet type that you've overlooked, but actually made provision for in the above rules is the Type P ... Pre-Biotic planet. In the "RESIDUAL GEOTHERMAL HEATING", you use stellar age to help determine planetary temp. But you could also use this same stellar age to set habitable planet types as "pre-biotic", if the age was in the "Young" or perhaps "Aged" groups.


This is taken care of under my NPR rules.

crucis wrote:Oh, something else... Immediately under the "ATMOSPHERIC THICKNESS" header, you list the progression of atmosphere thinknesses as "vacuum -> very thin -> thin -> average -> thick -> dense -> massive". However, there are no "average" atmosphere thicknesses listed in the tables. They always seem to progress from thin to thick.


Ooops no idea how that slipped in there. Average doesn't exist. Fixing it after this post.

And in the "HABITABILITY FACTORS" table, I'd replace "Uninhabitable" with "Deadly". (Ultra uses the term "Death" environment, but I think that "Deadly" is a better use of the language. "Death" is a noun, "Deadly" is an adjective... and I think that an adjective works better and sounds better in this circumstance.)


Well, I'm tempted to move all the habitability stuff to the NPR section because it is a subjective value. What is habitable or deadly to one type of race, is the opposite for another. Etc.
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Re: Sysgen Topics*: Planets (day 6)

Postby Crucis on Wed 26 Aug 2009 16:23

Cralis wrote:
crucis wrote:
cralis wrote:Type-N/SN: Ocean
These are Type-T or Type-ST worlds where the vast majority of the planet is covered with water (> 90%). These worlds will pretty much only have oxygen-based atmospheres simply because solar evaporation will create most of the atmosphere from the water.


Interesting. However, I think that you missed an opportunity, code-wise here... I suspect due to inertia. I edpect that you created the N/SN codes while the old O# codes still existed. However, now that H/B/F have replaced the O# codes, I would suggest using O and SO instead of N/SN, since "O for Ocean" is a solid mnemonic.


It has for years been generally accepted that "N" is an ocean world. I don't remember where I saw the proposed nomenclature - it was an international astronomy website - but I originally found it in a ST:NG technical manual and it had the address.


Bah. I don't care about "international" standards. I care more about Starfire standards and using good, memorable mnemonics. And the only thing memorable about SN is SuperNova. O/SO for "Ocean" makes much more sense.



crucis wrote:
cralis wrote:Type-GI: Gas/Ice
These are Type-G planets that have a different chemical composition. These will have more noble gases and other gases than simply H/He, although H/He is usually still a big part of their atmosphere. Otherwise, other than color, these are pretty much the same.

Type-I: Ice
In this version the Type-I worlds are going to be Ice or Rock/Ice worlds like Pluto. They aren't as common, as most of what ULTRA calls Type-I will be Type-GI instead.


Exactly how is this version of a Type I world different from a Type F world? I see the Type F world as fitting this description to a "T".


Type-F worlds are entirely rocky. Type-I worlds are entirely or mostly ices, probably methane, ammonia, carbon monoxide, along with water ice. Similar to Triton, except more ice less rock. Type-Is were speculated way back when they thought Pluto (and other KBOs) were thought to be mostly water ice, methane ice, ammonia ice, etc., with a very small core. However, more recently they are beginning to think it is mostly water ice with a small radioactive rocky core. Either way in about 6 years we'll get some solid evidence.



I'm not fond of changing Type I to Type GI. For one thing, in many fonts that "GI" looks like a G followed by a small "L". Perhaps Type IG might be better for Ice Giant.

Regardless, I really see no reason to not merge the above Type F and Type "I" into a single Type F with the assumption that some Type F's are more rocky and some are more "Icy".


crucis wrote:BTW, a potentially interesting planet type that you've overlooked, but actually made provision for in the above rules is the Type P ... Pre-Biotic planet. In the "RESIDUAL GEOTHERMAL HEATING", you use stellar age to help determine planetary temp. But you could also use this same stellar age to set habitable planet types as "pre-biotic", if the age was in the "Young" or perhaps "Aged" groups.


This is taken care of under my NPR rules.


Seems to me like it belongs right here, with the rest of the planetary type rules...

crucis wrote:Oh, something else... Immediately under the "ATMOSPHERIC THICKNESS" header, you list the progression of atmosphere thinknesses as "vacuum -> very thin -> thin -> average -> thick -> dense -> massive". However, there are no "average" atmosphere thicknesses listed in the tables. They always seem to progress from thin to thick.


Ooops no idea how that slipped in there. Average doesn't exist. Fixing it after this post.


Why shouldn't there be an "average" atmospheric density? It makes plenty of sense to me. Going from thin to thick is what seems "wrong" to me. :|

And in the "HABITABILITY FACTORS" table, I'd replace "Uninhabitable" with "Deadly". (Ultra uses the term "Death" environment, but I think that "Deadly" is a better use of the language. "Death" is a noun, "Deadly" is an adjective... and I think that an adjective works better and sounds better in this circumstance.)


Well, I'm tempted to move all the habitability stuff to the NPR section because it is a subjective value. What is habitable or deadly to one type of race, is the opposite for another. Etc.


I wouldn't move this to NPR rules as this is an issue for more than just NPR's. It probably belongs with the colonization rules, since that's where population and habitability issues interface.
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Re: Sysgen Topics*: Planets (day 6)

Postby krenshala on Wed 26 Aug 2009 21:03

Personally, I don't like the ST, or for these, SN (or SO) names. My take is it should be the type and the mass listed. The only difference between type T and type ST is the mass ... so I list it as a type T, mass x. If you already know the planetary types, you don't have any confusion this way, and it removes the need to come up with a "special" name for that Mass 1 (or Mass 0) habitable world you just created in the latest system -- its just a T1 (or T0) instead of the more "standard" T2 or T3 world. :)

Matt, overall I like the concept, though there are a number of things I think should be done (slightly) differently. The biggest change I'd make is the density/diameter tables. A quick check of Wikipedia lists densities from 5.515 g/cm^3 (Earth) down to 0.687 g/cm^3 (Saturn) with most being in the 1.2 to 2.7 range. I'm assuming you are using kilometers for the diameter value?

I've some other comments, but my brain isn't working well enough right now (bad storm rolling through Austin right now, any my sinuses act like barometers :cry: ) so I'll save them for later. I will post some data I gather, however, as it might help explain my thinking above:

blargh! i can't figure out tables in BBCode :(
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Re: Sysgen Topics*: Planets (day 6)

Postby Cralis on Thu 27 Aug 2009 00:27

Some of the values have changed over time (mostly other planet's data, and not by a lot admittedly), and a few others were suggestions made by Ed. I mostly have just copied that diameter/gravity/density stuff straight from his original suggestions for those sections.

I have always intended to go back over all this stuff someday (for the tenth time) but I have brought this to the SDS table for the purposes of discussion. Any research you do will be greatly appreciated :-)
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Re: Sysgen Topics*: Planets (day 6)

Postby Crucis on Thu 27 Aug 2009 14:36

Heya, Matt, where did you get the temp ranges for the various planet types or how did you derive them?

I did the BB temp for Venus and it didn't jibe with the temp for Type V planets in your table. (It was cooler than the listed temp range.)
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Re: Sysgen Topics*: Planets (day 6)

Postby Cralis on Thu 03 Sep 2009 02:30

I answered Fred's question via chat, for everyone else the answer is that the temperature ranges are based on planets here in the solar system, and then higher and lower ranges are based on known values for certain common elements to change form (for example, metals to liquid form) with some rounding involved. I know that some of these temperatures could probably use some adjusting, and as mentioned before I'm working on redoing the entire thing. Future topics of discussions I guess :-)

NOTE: Added the missing Greenhouse / AEA table. Thanks to Fred for pointing out I was missing something.
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Re: Sysgen Topics*: Planets (day 6)

Postby Crucis on Fri 04 Sep 2009 13:47

Matt, there are still some minor errors in the planetary data.

1. In the list of mass 1 planet types, there's an entry for Type O3. What's an O3 planet? There's no mention of an O3 planet type anywhere else in this entire post. (I'm thinking that you may mean Type H, but am by no means certain.)

2. The planet type M column in the atmosphere type table is missing the die roll values between 81-96.



There may be others as well that I haven't noticed yet...
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Re: Sysgen Topics*: Planets (day 6)

Postby Crucis on Sun 06 Sep 2009 00:06

I was thinking about the Blackbody Temp formula ( Temp = K * (SUM [L / (g * a^2)]) ^ 0.25; where a = radius of the planet's orbit in LM, from the star), when it occurred to me that there is a rather serious problem with the SUM'ing portion of the formula.

The SUM'ing portion of this formula exists to merge the effects of the various stars' luminosities in a poly-star system. However, the formula as written implies that the planet's orbital distance "a" for the orbit around its own star is used in each "L/(g* a^2)" term. This is simply wrong. Let me explain why in not mathematical terms.

Let's assume that we have a relatively distant binary, for an extreme example, wherein each star is a Sol-like G2 type star with a luminosity of 1, and comp B is 2 StMP away. And you have planet X orbiting component A at, say, 10 LM. Now, while comps A and B both have L=1, it should be patently obvious that comp A will have a vastly greater thermal impact than comp B on planet X.

Back to the math... I contend that the "a" value for comp B's contribution to the L/(g*a^2) should actually be equal to 2 StMP (720 LM), since that is pretty much the average distance of planet X from comp B.

About the only time that "a" should be equal for a planet in a binary system, is if the planet is orbiting both stars in a very close binary setup.

=======


On a very related point, while I can see that this SUM'ing part of the formula is technically correct, I contend that in nearly all poly-star systems, it is generally going to be pointless, unless comp B is amazingly close to comp A. Of course, if you're talking about a close binary where the planets are orbiting both stars, then the SUM'ing part of the formula is important. Otherwise, it's probably a waste of time unless comp B is less than 100 LM from comp A (and then the impact is still only about 1K additional degree of temp.

Of course, if this is in a sysgen program, it's no big deal, as long as the "a" distance is correctly defined for each component, as I described above.
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Re: Sysgen Topics*: Planets (day 6)

Postby Cralis on Sun 06 Sep 2009 00:32

Because it is a SUM, you calculate EACH star's value for a separately. And in that note I gave you the other day, you should have seen that he recommended you calculate a for the minimum and maximum values for each part of the orbit in relation to each star. Remember the "wouldn't this be better as an integral" comment I made? (and you said no, because most people couldn't do them)
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Re: Sysgen Topics*: Planets (day 6)

Postby Crucis on Sun 06 Sep 2009 00:44

Well, duh, to the calculating them separately...

But the KEY is that the 'a' value is different for each star!!!


And for even moderately distant component stars, the L/g* a^2 term will be entirely meaningless...
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